Patterns and Perspectives in Environmental Science NATIONAL SCIENCE BOARD 1972 /CO. Patterns and Perspectives in Environmental Science Report Prepared for the National Science Board National Science Foundation 1972 **T V- < at UJ Q. % UJ 0 -.2 - 4 1 1 , 1 , 1 , 1 , 1 1 1 1 7 0 80 90 1900 10 20 30 40 50 60 7 3 YEAR The mean observed temperature variation for the northern hemisphere has here been adjusted for the time lag of the system, the warming effect of CO,, and the effect of both stratospheric (volcanic) and tropospheric dust. The dust effect ex- plains 80% of the variance of the adjusted temperature, with 63% due to strato- spheric and 17% due to tropospheric dust. The resulting curve shows what tempera- tures would be observed under conditions of direct solar radiation with cloudless skies, although some residual errors remain. (Compare Figures III-4, 8, and 9) 71 PART III — CLIMATIC CHANGE numbers and control of energy. Thus man can, and probably has, modified the climate of the earth. The Climates of the Past Century From late in the nineteenth century until the middle of the twentieth, the mean temperature of the earth rose. During this time the carbon dioxide content of the atmosphere rose enough to explain the global temperature rise — apparently the first global climatic modification due to man. At the same time, local production of particulate pollution was starting to increase rapidly due to mechanization and industrialization. By the middle of the twentieth century, these trends — amplified by a general population ex- plosion and a renewal of volcanic activity — increased the worldwide particulate load of the atmosphere to the point where the effect of these particulates on the global albedo more than compensated for the carbon di- oxide increase and world temperatures began to fall. The total magnitude of these changes in world or hemispheric mean temperature is not impressive — a fraction of a degree. However, the difference between glacial and non- glacial climates is only a few degrees on the worldwide average. Actually, it is not the mean tem- perature of the earth that is impor- tant, but rather the circulation pattern of the atmosphere. This is stronglv dependent on the temperature differ- ence from the tropics to the poles. The same man-modifiable factors that affect the mean temperature of the globe-albedo and carbon dioxide — even if applied uniformly over the globe — will have the effect of chang- ing the meridional temperature gradi- ent and thus the circulation pattern and resultant weather pattern. It is this change of pattern that is of prime concern. Dzeerdzeerski in the Soviet Union, Kutzbach in the United States, and Lamb in England have all pro- duced different kinds of evidence that the circulation patterns have changed in the past two decades. In turn, the local climates show change — some regions wetter, some drier, some colder, some warmer — though some remain unchanged. The most striking changes have been where the effects of the change are cumulative, such as the slightly changed balance between evaporation and precipitation in East Africa which has caused the level of great lakes such as Victoria to rise markedly. Another case is the balance between ice wastage and production that has changed enough in the last decade to bring drift-ice to the Icelandic shores to an extent unknown for a century. It would be most useful to know what the cumulative ecological effect of these local or regional changes might be. Since biological selection in re- sponse to environmental changes usu- ally requires a number of generations to show the total effect of the change, it is probably too soon to know the total ecological impact of the present change. Here we can only look to the past to see what is possible. The Lesson of History The advent of radiocarbon dating has given a new dimension to the study of the variety of paleobotany known as palynology. It is now pos- sible to put an absolute time-scale on the record of environmental change contained in the pollen assemblages recovered from bogs and lake sedi- ments. In the context of the present discussion, the most startling result is the rapidity with which major envi- ronmental changes have taken place. If we examine the most carefully studied and best-dated pollen profiles, we find that the pollen frequencies often show a quasi-exponential change from, for example, an assemblage that might indicate boreal forest to an assemblage typical of mixed hard- woods. Calling the time required for half the change to occur the half-life of the transition, it appears that such major changes in vegetation may have half-lives of a couple of centuries or less. (Greater specificity must await analyses with much finer time-resolu- tion than has been generally used.) Since the plants integrate the climate, the half-life of the climatic change must be shorter still! With the agricultural land use of the world still reflecting the climatic pattern almost as closely as the native vegetation did, a major shift in cli- matic pattern within a century could be disastrous. Unlike the past, migra- tion into open lands is not possible: there are none, and forcible acquisi- tion of agricultural land with a favor- able climate is not acceptable. Only in a few nations would a combination of regional variety and advanced tech- nology allow an accommodation to a major climatic change. What We Need To Know Faced with the possibility that we are well into a climatic change of ap- preciable magnitude, of man's mak- ing, there appear a number of ques- tions to which answers are urgently needed. Since in the past there have been rapid changes in climate due to natural causes, such as major changes in vol- canic activity, what is the probability of increased volcanism in the next few decades adding to the pollution of the atmosphere made by man and thus speeding up the present climatic change? How far will the present climatic change go? It appears that the change from a glacial climate to a nonglacial climate occurred with great rapidity. Would the opposite change occur as fast? What chance is there, on a rela- tively short time-scale, to control the sources of turbidity? 72 CAUSES Ol CHANGE If we have reverted to the climate characteristic of the early 1800's, what displacements in the world agricul- tural pattern will occur in the next decade? The answers to these and a host of related questions will require a much more sophisticated knowledge of cli- mate and the man-environment sys- tem than we now possess. Time is short and the challenge to science is clear. Environmental Change in Arid America One of the great controversies in ice-age paleoecology is how to explain the virtually simultaneous coast-to- coast extinction of large mammals in North America around 11,000 years ago. We know, for example, that ele- phants once existed even in the pres- ently arid lands of the West. Paleon- tologists have commonly recovered the bones of Mammuthus columbi in arid America, along with bones of other extinct large mammals, includ- ing horses, camels of two extinct genera, extinct bison, and ground sloth. Did the climate change suddenly? Fossil elephants and the like inevitably provoke visions of a wetter climate and a more productive ecosystem than today's arid land will support. But the fossil-pollen record has indi- cated otherwise. Fossil Pollen and Other Forms of Evidence The technique of fossil-pollen anal- ysis has proved of unique value in determining what the vegetation and, by implication, the primary produc- tivity of arid America must have been during the period when this region, along with the rest of the continent, supported large numbers of native large mammals. Pollen is a very popular fossil be- cause it is produced in quantity by certain plants and, thanks to its acid- resistant outer wall or shell, is pre- served in many types of sediments. Unlike fossils of larger size, pollen is usually dispersed evenly throughout a deposit rather than aggregated in one or a few distinct beds. Under relatively uniform sedimentation, as determined by closely spaced radio- carbon dates, one can estimate the intensity of the local pollen rain through time, as Davis has done in a study of vegetation history at Rogers Lake, Connecticut. Different vegeta- tion zones shed different amounts of pollen — a tundra much less than a forest, for example. This is revealed by the fossil pollen extracted through hydrofluoric-acid treatment of lake muds. In many deposits, especially in arid lands, absolute values cannot be esti- mated. The relative amounts of the dominant pollen types in a deposit can be compared with the pollen content of sediments presently being deposited in areas of natural vegetation. Literal interpretation of the relative pollen percentage cannot be made — i.e., 10 percent pine pollen does not mean that 10 percent of the trees in the stand were pines. But the pollen spectrum of all types identified in a fossil count can be matched, through computer programs or simple direct comparison, with the pollen rain of modern natural communities. This method works especially well in west- ern United States, where there are extensive areas of relatively undis- turbed vegetation. In this way, any major or increasing number of minor changes in vegetation through time can be detected. As opportunity allows, the fossil- pollen record can be compared with other forms of evidence. Macrofossil remains of plants, including seeds and leaves, are found in certain lake muds. They have been reported in remark- able abundance in ancient wood-rat middens of certain desert regions by Wells. The oldest rat's nests studied by Wells are over 30,000 years in age, essentially older than can be deter- mined by the radiocarbon method. The Climatic Record of Western America The fossil record of radiocarbon- dated deposits covering the last 30,000 years in western America indicates an initial cool, dry period becoming colder and wetter by 20,000 to 16,000 years ago. At this time, there were ponderosa-pine parkland and pinyon- juniper woodland at elevations about 3,300 feet below their present lower limits on western mountains. The fate of prairie, both short and tall grass- land, is unknown. The present prairie region was occupied by spruce in the north and pine in the south. This suggests that arid America, like other regions, was affected by the late Pleistocene cooling associated with ice advance over Canada. Around 12,000 years ago the cli- mate changed rather rapidly, becom- ing warmer and drier, until conditions were only slightly cooler and wetter than now. Modern vegetation zones have occupied their present positions, with minor fluctuations, continuously for the last 8,000 years. Thus, the record shows that the environment of western America in- habited by mammoth, camels, native 73 PART III — CLIMATIC CHANCE horses, and bison at the time of their extinction 11,000 years ago was not vastly different from what we know at present. Why, then, did the ani- mals die? Fossil pollen and other evidence from the radiocarbon dating of extinct Pleistocene faunas seem to indicate that no environmental defects will explain this phenomenon. One must look elsewhere. And the only new variable in the American ecosys- tem of the late-glacial period is the arrival of skilled Stone Age hunters. These events of thousands of years ago have major implications for mod- ern-day range management. Implications for Modern Range Management In part, the concept of the West as a "desert" is based on the fact that grass production is indeed quite low. But the dominant woody plants found across the one million square miles of western America — the creosote bush, sagebrush, cactus, and mesquite — do yield large amounts of plant dry- matter annually. Primary productiv- ity data on these western shrub com- munities are less abundant than one might wish. Nevertheless, such data as do exist indicate that shrub com- munities in southern Arizona may yield 1,400 kilograms per hectare a year, considerably more than adjacent grassland under the same climate (12 inches of precipitation annually). Observers have overlooked or writ- ten off this annual production, per- haps because it is often avoided by domestic livestock. Indeed, fifty years of range management in the West has been aimed at destroying the woody plants to make way for forage more palatable to cattle. The effort has been singularly futile and should be abandoned. The Future of Western Meat-Pro- duction — The dilemma faced by the range industry in arid America is that beef can be produced faster, more efficiently, and at less expense in the southeast or in feedlots. If this fact is accepted, one can make a case for keeping large areas of arid America as they are, at least until much more is known about primary production of the natural communities and until some value for Western scenery can be agreed upon. Some large, wealthy ranchers have already recognized this and have disposed of their cattle. More should be encouraged to do so. If a meat-producing industry is to be established in the marginal cattle lands in the West, it should be based on new domestic species, animals that are better adapted to arid environ- ments than cattle and that are adapted for efficient browsing rather than grazing. Potential New Domesticates — One obvious source for potential new domesticates is Africa, where arid ranges that barely sustain cattle are supporting thrifty herds of wilde- beest, kongoni, zebra, giraffe, and kudu. In size and general ecology, the African species bear at least general resemblance to the extinct Pleistocene fauna of the Americas. They did not invade the New World during the ice ages because they failed to range far enough north to be able to cross the Bering Bridge, the only natural method of intercontinental exchange open to large herbivores. Many natu- ral faunal exchanges of arctic-adapted herbivores did occur over the Bering Bridge in the Pleistocene. Some, but not all, of the invaders re-adapted to warmer climates of the lower latitudes. In summary: (a) Studies of fossil pollen and other evidence of the last 30,000 years reveal no environmental defects that might explain the extinc- tion of many species of native New World large mammals 11,000 years ago. (b) The only known environ- mental upset at the time of large ani- mal extinction was the arrival of Early Man. (c) The cattle industry of west- ern America is marginal, being main- tained for reasons of its mystique, not for its economics, (d) If a more pro- ductive use of the western range is desirable, experiments with other species of large mammals should be begun now, as indeed they have been on certain ranches in Texas, New Mexico, Mexico, and Brazil. 74 PART IV DYNAMICS DFTHE ATMOSPHERE-OCEAN SYSTEM 1. OCEANIC CIRCULATION AND OCEAN- ATMOSPHERE INTERACTIONS Oceanic Circulation and the Role of the Atmosphere The ocean circulation is one of the primary factors in the heat budget of the world. The circulation is impor- tant not only internally to the ocean but also to the overlying atmosphere and, indeed, to the climate of the entire earth. Together the sea and the air make a huge thermal engine, and it is not possible to understand either without having some compre- hension of the other. Any studies of ocean circulation must inevitably in- volve this coupling with the atmos- phere. The Present State of Understanding Studies of ocean circulation have progressed a long way in the past fifty years. Measurements of the characteristics of the ocean at great depths have produced at least a gen- eral sense of the major deep circula- tions. And extensive theoretical de- velopments over the same period have given us some glimmering as to why the circulations are what they appear to be. Ocean Variability — Both the ob- servational and theoretical studies have dealt mostly with a steady-state ocean or the long-term mean of an ocean. (See Figure IV-1) During the past few years, however, some data have been accumulated that allow us to speculate a bit about the variability of the ocean. Like mean circulation, variability is closely coupled to the atmosphere, and variations in ocean circulation may lead to, or stem from, variations in atmospheric phenomena. For example, one of the critical parts Figure IV-1 — SEA-SURFACE TEMPERATURE AVERAGE EMPERATURE IN C NORMAL COLDER- I I £ WARMER The figure shows sea-surface temperatures represented as deviations from global average values of the sea-surface temperature. The global average value for each 5° latitude band is marked at the right-hand edge of the world map. Note the extent of the cold equatorial water in the Pacific (from the coast of South America westward halfway across the Pacific) and the warm water west and north of the United Kingdom. 77 PART IV — DYNAMICS OF THE ATMOSPHERE-OCEAN SYSTEM of the heat engine is the Norwegian Sea, an area where warm saline sur- face water from the Gulf Stream is cooled by contact with the atmos- phere, made dense, and returned to the open Atlantic as dense deep water in such quantity as to create a recog- nizable subsurface layer extending throughout the Atlantic, Antarctic, Indian, and Pacific oceans. In this case, the power to drive this thermo- haline engine comes from heat ex- change with the atmosphere. Warming of the surface waters in low latitudes and cooling in high lati- tudes creates easily recognizable ef- fects on the circulation of the ocean. The effect of this exchange on the atmosphere is equally important, not just locally — in that the coast of Norway remains ice-free — but also in the larger sense of general effects on the world atmospheric climate. The budget of this heat exchange and the details of its various expenditures must be learned if the earth's climate is to be understood. Seasonal and nonseasonal variations of the heat exchange, and their causes and ef- fects, must be studied. The Gulf Stream is both a cause and an effect of this exchange. It would exist in any case as a conse- quence of the wind-driven circulation in the trade-wind and westerlies areas, as do, in a weaker form, its South Atlantic, North Pacific, and South Pacific counterparts. (The heat and water sink of the far North Atlantic requires a vaster flow in the Gulf Stream than in the other western boundary currents.) But variations in the strength of the Gulf Stream may be either causes or consequences of variations in heat exchange in the Norwegian Sea. Although the effects of these variations may be severely damped by the time the waters enter the immense reservoir of the abyssal ocean, there is no certainty that their effects on the far reaches of the ocean are negligible. Some of the most interesting varia- tions yet observed in the ocean are in the North Pacific, where bodies of surface water thousands of miles in diameter remain warmer or colder than their seasonal means for periods ranging from three months to over a year. Such features seem to be char- acteristic of the North Pacific. Thus, a typical map of surface temperature is not one that is very near the norm everywhere, with many small highs and lows; instead, the whole North Pacific may consist of three to five large areas of deviant temperature. Such features have been noted only in the past fifteen years. They are beginning to receive the attention of meteorologists, as well as oceanogra- phers, since their consequences for the atmospheric climate cannot be discounted in attempting to under- stand and predict the world's weather. Prediction — Our present under- standing of the ocean is barely suffi- cient to account for the major cir- culations in a general way. Some preliminary attempts are now being made to predict specific features of ocean behavior, most of them being based on the persistence of deviations from the mean. That is, if an area shows an abnormally high surface temperature in one month, this anom- aly is apt to endure or persist for several months more and to diminish to the norm slowly. Strictly speaking, this is not prediction but merely the extrapolation of a present feature. More ambitious predictions are being contemplated, but they are still in very early stages. Advances in Instrumentation Devices to measure ocean currents have improved greatly over the past ten years. They have been used to monitor changes in position of the Gulf Stream, to measure its deep flow, and to investigate some of the principal inferences about deep cir- culation in the Pacific and Atlantic oceans. Considerable improvement has also been achieved in instruments for measuring water characteristics. Moored buoys of various kinds have been developed for deep-water use within the past decade. They are used for monitoring certain character- istics of the ocean and atmosphere, including wind, air, and sea tempera- ture, subsurface temperature, waves, and, possibly, water velocity. These measurements can either be recorded and recovered by vessels or trans- mitted immediately by radio to ap- propriate shore bases. The future may see interrogation and retransmission of signals by satel- lite. The advantages of such monitor- ing stations would include relatively inexpensive operation (compared to weather ships) and the ability to gather data from regions that are out- side normal shipping lanes but may be extremely pertinent to ocean and weather studies. Deficiencies in the Data Base The data base for study of the ocean consists of measurements of water characteristics in various loca- tions and depths at different times and measurements of currents, waves, tides, and ocean depths. In some areas and some seasons, this data base is adequate for a long-term mean to be established; it is not continuous enough in time, however, to allow for adequate study of variations from the long-term mean. In other areas and seasons, the data base barely exists. High-latitude areas in winter have hardly been explored. Our knowl- edge of the deep arctic is extremely limited. Some few winter data are available from the antarctic region. The deeper parts of the ocean may be better represented in the present data base than the surface parts, since the deeper parts show less time-variation than the upper layers. Other parts of the data base in- volved in investigating ocean circu- lation include atmospheric-pressure observations and wind measurements, air temperature and the like. These, 78 OCEANIC CIRCULATION AND OCEAN-ATMOSPHERE ITONS too, are limited both in time and space. Major shipping lanes are fairly well measured in many seasons. Among the more systematically meas- ured areas are the North Sea, the California Current system, and the Kuroshio Current. But data from the areas that ships avoid, either because of bad weather conditions or because they do not represent profitable ship routes, are generally sparse. Not only is the arctic poorly represented even with atmospheric information, but also the South Pacific and large parts of the South Atlantic. Very few areas in the world are represented by a data base sufficient to allow for sea- sonal and nonseasonal variations. Numerical models of the ocean are also still in an early stage of develop- ment. What is Needed A proper understanding of air-sea interchange and of deep flow are among the most urgent tasks of oce- anic circulation research. We need to determine which data are critical, ob- tain them, and use them in mathe- matical modeling of the ocean. Topics of practical importance to man, re- quiring urgent study, include fisheries production in the world ocean; this is related to ocean circulation, since the latter controls the availability of plant nutrients. Better understanding of the Arctic Ocean is crucial to proper evaluation of its possibilities as a commercial route for surface vessels or subma- rines. Better knowledge of the deep circulation and the rates of exchange of ocean water — both from the sur- face to the bottom and from the deeper parts of one ocean to the deeper parts of another — is particu- larly important in the light of new concerns over contamination and pol- lution. While the ocean can act as a reservoir to absorb, contain, and re- duce much of the effluent now being produced, it is not of infinite capacity nor can it contain materials indefi- nitely without bringing them back onto the surface. Time-Scale — It is not possible to lay out a time-scale for many of the things that must be investigated. For the problem of describing the mean ocean, another ten or fifteen years might be sufficient. In that period of time, it would be feasible to collect the additional data needed without substantially expanding the facilities. In order to accomplish this, however, the various institutions capable of carrying out the requisite measure- ments would have to devote a greater part of their time to this subject — and this may not be desirable. Developing a data base to study the time-variable ocean is a different sort of problem. Since our under- standing of the nature of time-varia- tions is still in a primitive stage, we must first learn how to observe the phenomena and then begin a system- atic series of observations in the ap- propriate places. Progress has been made in learning how to do this from buoy deployments in the Pacific and Atlantic oceans. These are prelimi- nary, however, and must be greatly augmented before we can really un- derstand even the scale, much less the nature, of the anomalies being observed. Understanding of this kind usually advances step by step from one plateau to another, but the steps are highly irregular both as to height and duration, and a feasible time- scale cannot be estimated. Necessary Activity — On the one hand, the scale of the problems dis- cussed here suggests large-scale, large-area, heavily instrumented re- search carried out by teams of in- vestigators. On the other, the history of ocean circulation research has shown that some of the greatest con- tributions were made by individuals — e.g., Ekman transport, Stommel's westward intensification, Sverdrup transport. A balance is required be- tween large-scale programs compa- rable to the space program and indi- vidual small-scale projects. One of the first needs is to train people able to work on problems of both the ocean and the atmosphere. The two fields have been far too sepa- rated in most cases. People trained in mathematics and physics are avail- able, but the average student finds it difficult to acquire a working back- ground in both the oceanic and at- mospheric environment; indeed, many people trained in physics and mathe- matics have limited backgrounds in either environment, relying on theory without adequate knowledge of the structure of the two systems. On Predicting Ocean Circulation Nonspecialists tend to think of ocean circulation systems as being primarily a matter of geographical exploration. We are not going to dis- cover many new undercurrents, how- ever. Nor will simple-minded "moni- toring" of ocean currents teach us much. Twenty years of looking for — and not finding — relations be- tween changes in patterns of applied wind stress and the total transports of currents like the Gulf Stream where it passes through the Florida Straits warn us that the chain of cause and effect in the ocean is rather 79 PART IV — DYNAMICS OF THE ATMOSPHERE-OCEAN SYSTEM complicated and that the primary problem is to make more profound our understanding of the ocean as a hydrodynamical phenomenon. What We Know — and Don't Know It has been pointed out that there has been a really effective growth of understanding of ocean surface waves only in the last decade. And ocean surface waves are probably the most easily observable and dynamically linear of ocean phenomena. Internal waves and oceanic turbulence are not so easily observable, and treatments of these phenomena are a thin tissue of preliminary theory largely unsup- ported by observation. Studies limited to rather high-frequency phenomena actually represent the kind most nearly duplicable in the laboratory. There is a small body of theory concerning oceanic circulation, but it deals only with the climatological mean circulation. The role of medium- scale eddy processes in ocean circula- tion is completely unknown, although current measurements indicate that they can be very important — as, for example, they are in the general circu- lation of the atmosphere. A two- pronged development of mathematical modeling and fairly elaborate field in- vestigation is going to be necessary to develop much further our under- standing of the hydrodynamical in- teraction of these eddies and the mean circulation. (A working group of the Scientific Committee on Ocean Research of the International Coun- cil of Scientific Unions recommended a "Mid-Ocean Dynamics Experiment" (MODE).) Considering the three- dimensional detail of velocity struc- ture and its development in time that such a measurement program will entail, it seems clear that a major input from the engineering commu- nity will be needed.) Technological Limitations Oceanography is not presently competent technologically to tackle the tasks of measurement that are necessary in trying to tinravel the dynamical features of large-scale mo- tions. The difficulty is simply that one needs to map variables like velocity rather densely in large volumes (per- haps 2 miles deep and 300 miles on a horizontal side) for rather long pe- riods (perhaps a year) with sufficient accuracy that reliable statistics can be calculated for complicated functions like triple correlation products. Many different modes of motion are occur- ring simultaneously, and we need to be able to separate one mode from another in order to compute interac- tions. Therefore, a great variety of arrays of sensors need to be arranged in different configurations and on different scales for gathering the kind of data required from the ocean. Some test portions of the ocean will need to be heavily instrumented in a manner more sophisticated than pres- ent small-scale observational opera- tions can achieve. It is safe to say that solutions of problems of internal waves, the general circulation and eddy processes, and such important local processes as coastal upwelling are simply going to have to wait until major new instrumental arrays be- come available. There is a limit beyond which in- ferior technique cannot go. It needs to be made very clear what a helpless feeling it is to be on a slow-moving ship, with a few traditional measuring techniques like water bottles and pingers on hand, trying to keep track of a variable phenomenon like an eddy that won't hold its shape. A faint idea of the elusiveness of the phenomenon can be conveyed to any- one who has tried to pick up mercury with his fingers or who has watched a teacher trying to keep track of her pupils on an outing to a public park. But the ocean environment is so much larger, so much harder to see, that we don't bring many of "our children" home. Measurement in large-scale ocean physics illustrates this limit very well. Further theoretical devel- opment is simply going to have to wait upon adequate measurement technique. The theoretical difficulties are not serious; mathematical model- ing can be worked by machine once sufficient insight has been gained as to what is actually going on in the ocean. The Need for Mathematical Models Some advances in climate control, pollution evaluation, and numerical weather forecasting might be achieved simply by extending present land- based meteorological networks into the ocean by means of buoys. Per- haps a superficial knowledge of tem- perature on a coarse grid in the upper 100 meters of the ocean will be useful to meteorologists. But this will not provide the basis for a quantitative, rational, ocean-prediction system. In order to be able to predict the mechanism of the ocean it is neces- sary to have numerical-mathematical models that have been verified by comparison with actually observed case histories of oceanic motion. Be- cause there are several modes of such motion, these experiments or com- parisons have to be made on several different scales. But to date they have not been made. They are beyond our technical means. Actually, it is too early to try to design an oceanic monitoring system; some experimental measuring systems are needed first — aimed squarely at providing input for mathematical numerical modeling of the basic hy- drodynamical processes at work. Suc- cessfully tested models could evolve into successful prediction schemes. If sufficient resources were mus- tered to start a good crew of instru- ment engineers on a sample program of measurement, sufficient progress might be made in carrying out one sample comparison of theory and observation to catalyze progress on the other necessary experiments. One has the feeling that the science is locked in a dead-center position, and that a mighty shove is going to be needed to get it rolling. 80 OCEANIC CIRCULATION AND OCEAN-ATMO1 1 IONS Hydrodynamic Modeling of Ocean Systems Waves and currents in the ocean can be organized into many different categories depending on horizontal dimension and the time-scale of vari- ability. Some of these categories are strongly interconnected, others al- most independent. In Figure IV-2 an attempt is made at classification, along with an indication of the principal ways in which each phenomenon has an impact on human activities. (The emphasis in this outline is on ocean- circulation phenomena; surface waves, tides, and storm tides are treated only briefly, although thev are admittedly important subjects from the stand- point of practical disaster-warning systems.) Present Status Wind Waves and Tidal Waves — The numerical models presently used to predict surface waves are essentially refinements of earlier operational models developed by the U.S. Navy; they have proved valuable to ship- ping. New computer models, how- ever, allow a much more detailed in- corporation of the latest experimental and theoretical advances in the study of wave generation. Furthermore, or- biting satellites may soon be able to provide a good synoptic picture of the surface sea state all over the globe. Given an accurate weather forecast, computer models would then be able to predict future sea states. Indeed, it may turn out that the ultimate limi- tation to wave forecasting will involve the accuracy of the weather forecast rather than the wave-prediction model itself. Operational models for predicting tidal waves (tsunamis) have been de- veloped for the Pacific, where the danger of earthquakes is greatest. As soon as the epicenter of an earth- quake is located by seismographs, the model can predict the time a tidal wave will arrive. Such warning sys- tems are being developed by the National Oceanic and Atmospheric Administration (NOAA) and the Japanese Meteorological Agency. Storm Surges and Tides — Most of the research in developing numerical models to predict storm tides has been carried out in Europe, in con- nection with flooding in the North Sea area. In the United States, storm surges caused by hurricanes ap- proaching the Gulf Coast have gener- ated the most interest. The results of these model studies appear promising. Graphs and charts based on the model calculations may be used by Weather Service forecasters in mak- ing flood warnings. The models will also be useful in the engineering de- sign of harbor flood-walls and levees. In time, computer models will prob- ably replace the expensive and cum- bersome laboratory models of harbors now used by coastal engineers. Figure IV-2 — CLASSIFICATION OF WAVES AND CURRENTS Time-Scale Local Intermediate Global Short (minutes) Surface Waves (shipping, shore erosion, offshore drilling) Tidal Waves (tsunamis) (safety of shore areas) Intermediate (hours/days) Ocean Turbulence and Mixing (pollution, air-sea interaction Storm Surges (safety of shore areas, hurricane damage) Tides (navigation) Long (months/years) Near-Shore Circulation (pollution) Circulation of Inland Seas (Great Lakes pollution, polar pack-ice models) Circulation in Ocean Basins (long-range weather forecasting, fisheries, climatic change) The chart classifies waves and circulations as functions of time and distance. 81 PART IV — DYNAMICS OF THE ATMOSPHERE-OCEAN SYSTEM Ocean Circulation — Over the past decade, three-dimensional numerical models for calculating ocean circula- tion have been developed by the So- viet Hydrometeorological Service and NOAA. The methods used are sim- ilar to those of numerical weather forecasting. Given the flux of heat, water, and momentum at the upper surface, the model predicts the re- sponse of the currents at deeper levels. The currents at deeper levels in turn change the configuration of temperature and salinity in the model ocean. Although active work in develop- ing these models is being conducted at several universities, the only pub- lished U.S. calculations are based on the "box" model developed at NOAA's Geophysical Fluid Dynamics Laboratory. This model allows the inclusion of up to 20 levels in the vertical direction and a detailed treat- ment of the bottom and shore con- figuration of actual ocean basins. Cox's calculation of the circulation of the Indian Ocean is perhaps the most detailed application yet at- tempted with the NOAA "box" model. Using climatic data, it was possible to specify the observed dis- tribution of wind, temperature, and salinity at the surface as a function of season. The model was then able to make an accurate prediction of the spectacular changes in currents and upwelling in response to the changing monsoons that were measured along the African coast during the Indian Ocean Expedition of the early 1960's. Application of the Model to Prac- tical Problems — The numerical mod- els designed for studying large-scale ocean circulation problems can be modified to study more local circula- tion in near-shore areas or inland seas such as the Great Lakes. Thus, numerical models may be useful for the many problems in oceanography in which steady currents play a role. A partial list includes: (a) long-range weather forecasting; (b) fisheries fore- casting; (c) pollution on a global or local scale; and (d) transportation in the polar ice-pack. Needed Advances The Data Base — Standard oceano- graphic and geochemical data provide a fairly adequate base for modeling the time-averaged, mean state of the ocean. The data base for modeling the time-variability of the ocean is extremely limited, however. Infor- mation on large-scale changes in ocean circulation as well as the small- scale variability associated with mix- ing in the ocean have not been gath- ered in any comprehensive way. Future progress in ocean modeling will depend on more detailed field studies of ocean variability. Such studies will establish the data base for the formulation of mixing by small-scale motions which must be included in the circulation model. Information on large-scale variability will provide a means for verifying the predictions of the models. Technical Requirements — The most promising approach appears to be the different arrays of automated buoys that have been proposed as part of the International Decade of Ocean Exploration (IDOE) program. Coarse arrays covering entire ocean basins, as well as detailed arrays for limited areas, will be required. Another technical requirement for ocean modeling is common to a great many other scientific activities: the steady development of speed in elec- tronic computers and the steady de- crease in unit cost of calculations. Manpower Training — Numerical models of currents have now reached a point where they can be of great value in the planning of observational studies and the analysis of data col- lected at sea. The models can be used in diagnostic as well as predictive modes. This is particularly true of the buoy networks proposed as part of the IDOE. In order to do this, however, more oceanographers will need to be trained to use the numeri- cal models and to carry out the com- putations. This action will have to be taken quickly if numerical models are to have much signficance in IDOE programs. Application of Ocean Modeling in Human Affairs As pointed out by Revelle and others, a large fraction of the added carbon dioxide (CO-) generated by the burning of fossil fuels is taken up by the oceans. However, few details are known concerning the ocean's buffering effect and how long it will continue to be effective. The ability of the ocean to take up CO- depends very much on how rapidly surface waters are mixed with deeper water. More detailed studies of geo- chemical evidence and numerical modeling are essential to get an un- derstanding of this process. A start in numerical modeling of tracer dis- tributions in the ocean has been made by Veronis and Kuo at Yale University and Holland at the NOAA Geophysical Fluid Dynamics Labora- tory. Another urgent task is to make an assessment of the effect of CO- and particulate matter in the atmosphere on climate. Present climatic knowl- edge does not allow reliable quan- titative predictions of the "green- house effect" due to CO- or the screening out of direct radiation by particulate matter. Published esti- mates have been based on highly simplified models that treat only the radiational aspects of climate. But no climate calculation is complete without taking into account the cir- culation of both the atmosphere and the ocean. Some preliminary climatic calculations have been carried out with combined numerical models of the ocean and atmosphere. But greater effort is required to develop 82 OCEANIC CIRCULATION AND OCEAN-ATMOSPHERE INTERACTIONS more refined ocean models if these climatic calculations are to be reliable enough to be the basis for public policy decisions on pollution control. Time-Scale of Significant Ad- vances — Since published papers on three-dimensional ocean circulation models have only recently begun to appear, rapid development should continue for at least another five years along present lines. In that time, ocean models should have reached about the same level of development as the most advanced atmospheric numerical models today. Within five years, at least the feasi- bility of application of numerical modeling to small- and large-scale pollution studies, long-range weather forecasting, and hydrographic data analysis should be well established. Another five years will probably be required to work out standard pro- cedures for using numerical ocean circulation models in these applica- tions. Effects of Antarctic Water on Oceanic Circulation Except for a relatively thin (slightly less than one kilometer) warm surface layer in the tropics and subtropics, the ocean is basically cold and fairly high in dissolved oxygen content. Ninety percent of the ocean is colder than 8 centigrade, with an oxygen content generally from 50 to 90 per- cent of the saturation level. This warm surface layer, because of its high stability, acts as an impervious cap over the cold abyssal water, blocking renewal (by the usual tur- bulent transfer methods) of the oxy- gen that has been consumed by various biological processes. warm and low-oxygen-content cir- cumpolar deep water (CDW) slowly flows southward and upward. Even- tually, it reaches the near-surface layers at the wind-produced Antarc- tic Divergence. Here, the intense thermohaline alteration resulting from the sea-air interaction converts the CDW into "antarctic surface water" (AASW), which is cold (near freez- ing, —1.6° to —1.9° centigrade) and relatively fresh. Some of the CDW is converted by more intense thermohaline alterations due to ice formation into a fairly dense con- tinental shelf water. At certain times, this shelf water drops to the sea floor where, on mixing with additional CDW, it forms the "antarctic bottom water" (AABW); neither the times nor the exact locations of the vertical motion are adequately known. The AABW has worldwide influence. It reaches far into the northern hemi- sphere in the western Atlantic and Pacific oceans. Though we do not know how the shelf water is produced, three meth- ods appear to be likely: (a) sea-ice formation; (b) freezing, melting, or a combination of these at the floating Why, therefore, is the bulk of the ocean so cold and highly oxygenated? In studying the relationship of tem- perature to salinity in the cold abyssal waters of the world ocean, one is struck by its similarity to that found in antarctic waters. This suggests that the oceanographic processes oc- curring in antarctic waters influence, in a direct way, the physical and chemical properties of much of the ocean's abyssal water. One may think of the antarctic region as a zone in which the abyssal waters can "breathe," renew their oxygen sup- ply, and release to the atmosphere the heat received at more northern lati- tudes. The Antarctic Water Masses Figure IV-3 — ANTARCTIC WATERS AND THEIR CIRCULATION POLAR FRONT ZONE ANTARCTIC DIVERGENCE ZTlUE^NTARCTirr^ \ A /?/ "^AiTARCTIC IURFACI WATER h(>' ICE SHELF SS™E -^^7i~.., ^ f. * A ( \ S7"7^\5\- se*s^^ — r „rU" \L T-, rf ■ TTl^ rn -Ttn ^rwfn__ rmJL 383 3mm 771 1 526 5 9136 197 8 4399 1959 "h-i-JL hi M 1596 6 I960 1961 m-i n 759 2 J hTI rh-rTHT-rrl rfh. 30" 28 9° 278° 200° 100° o C 30° 289° mm 400 1962 1962 1964 1965 1966 1967 * A ■ V / . \ . ">*IR ^ We* fJy^' 1 V x."*^ — ' s^ 1 V — \ n 1 n urn ^rfKT 4Th-rr " , n-T tl 401 6 mm 712 5194 1432 8 i □ ! Q 100 28 9° 278° mm 500 400 300 200 100 The figure shows a time-series of monthly air and sea temperatures and monthly precipitation amount as measured at Canton Island from 1950 through 1967. 85 PART IV — DYNAMICS OF THE ATMOSPHERE-OCEAN SYSTEM two years' periodicity, especially dur- ing the 1960's; at other times the rhythms were less regular. The mechanism of the equatorial air-sea rhythms is illustrated in Fig- ure IV-5, which shows that a six- month, smoothed time-series of atmospheric pressure in Djakarta, Indonesia (6°S. 107 E.), exhibits the same long-period trends as the sea- surface temperatures measured at Canton Island and by ships crossing the equator at 165W. When the barometric pressure in Djakarta is lower than normal, the equatorial easterlies heading for the Indonesian low become stronger than normal; this automatically intensifies the Pacific equatorial upwelling and cools the sea surface. The parallelism of the time-series of Djakarta pressure and Canton Island sea temperature is thereby assured. If wind profiles are observed along the equator at two opposite phases of the air-sea rhythm, as exemplified by November 1964, with its cool ocean and aridity, and November 1965, with its warm ocean and abun- dant rainfall at Canton Island, it is found that in November 1964 the equatorial easterlies swept uninter- ruptedly from South America past Canton Island toward a deeper-than- normal Indonesian low, whereas in November 1965 they stopped short of reaching Canton Island. The equa- torial upwelling — a by-product of the equatorial easterlies — extended almost to Indonesia in November 1964, while being confined to a much smaller area east of Canton Island a year later. Concomitantly, the equatorial rainfall was confined to the neighborhood of Indonesia in No- vember 1964; the following year it expanded from the west to beyond Canton Island, while Indonesia suf- fered serious drought. The propulsion of the air-sea rhythms resides in the atmospheric thermally driven equatorial circula- tion over the Pacific, which has its heat source (by condensation) in the rising branch, and heat sink (by radiative deficit insufficiently com- pensated by scarce precipitation) in its descending branch near South America. The oceanic counterpart to this atmospheric circulation is, in part, the westward surface drift and Figure IV-5 — WALKER'S "SOUTHERN OSCILLATION" The diagram shows the similarities in trend ot the time-series of sea temperature and pressure measured at and near the equator in the southern hemisphere. The dotted curve that follows that for Djakarta is based on data from Singapore. The rapid oscillations of the sea-temperature curve measured at the equator in 1958 and 1959 result from more frequent ship crossings — and hence a greater density of short- period detail — rather than from any unusual natural activity. the subsurface return flow and, addi- tionally, the circulation consisting of an upwelling thrust at the equator and sinking motion to the north and south of the equator. These ocean circulations are wind-driven and in- trinsically energy-consuming, but they exert a powerful feedback upon the atmosphere by slowly varying the areal extent of warm water at the equator and thereby varying the ther- mal input for the global atmospheric circulation. In November 1964, when cool up- welling water occupied almost the whole Pacific equatorial belt, the at- mosphere received less heat than in November 1965, when the upwelling had shrunk back into a smaller east- ern area. Consequently, the tropical atmosphere swelled vertically from 1964 to 1965. This swelling was most conspicuous over the Pacific at 160 W. longitude. Moreover, the swelling of the tropical atmosphere had spread all around the global tropical belt between 1964 and 1965, a global adjustment that is inevitable, since pressure gradients along the equator must remain moderate. North and south of the swelling atmosphere in the tropical belt, the gradient of 200-millibar heights in- creased from November 1964 to November 1°65, which indicated increasing westerly winds in the globe-circling subtropical jet streams. This can best be documented in the longitude sector from the area of Pacific equatorial warming eastward across North America and the At- lantic to the Mediterranean. The corresponding change at sea level could be seen most dramatically over Europe, where the moving low- pressure centers abandoned their normal track by way of Iceland to Scandinavia and, instead, in Novem- ber 1965 moved parallel to the strengthened subtropical jet stream and invaded central and southern Europe. Other associated rearrangements involved the arctic high-pressure sys- 86 OCEANIC CIRCULATION AND OCEAN-ATMOSPHL tern, which in November 1965 was displaced toward northern Europe and, consequently, on the Alaskan side of the pole left room for the moving low-pressure systems from the Pacific to penetrate farther north than normal. So much for a description of the air-sea rhythms. Supporting evidence is available from a few other case histories. The motivation for con- tinued research on the equatorial air- sea rhythms is the desire to develop skill in forecasting climatic anomalies. Current Scientific Knowledge The data base is, unfortunately, scanty. As mentioned earlier, Canton Island is the only place where a continuous record of the near-equa- torial air-sea interaction was main- tained; even there, scientific knowl- edge of the air-sea rhythms, extending vertically to great heights in the atmosphere, must be based mainly on a study of the years from 1950 through 1967. Oceanographic cruises in the equa- torial belt have been few and far between in space and time. The EASTROPAC Program, a series of internationally coordinated cruises in the eastern tropical Pacific and trans- equatorial cruises in the mid-Pacific, sponsored by the U.S. National Ma- rine Fisheries Service (NMFS), Hono- lulu, has been the best oceanographic effort to date to explore air-sea in- teraction in the critical area where the air-sea rhythms originate. Eess sophisticated, widely scattered ob- servations are available from com- mercial ships. Those collected by the NMFS in Honolulu from commercial ships that ply the route from Hawaii to Samoa have provided a time-series of equatorial sea temperature at 165°W., together with the corre- sponding sea-temperature series at Canton Island. The two records agree rather well as far as the long rhythms are concerned. Organized reporting of sea and air temperatures from commercial ships crossing the east and central part of the Pacific tropical zone is in good hands with the NMFS in La Jolla, California; the monthly maps issued by that institution are at present the best source of informa- tion on tropical air-sea rhythms. The Status of Instrumentation ■ — An important technical improvement in the ocean data reported from commercial ships will come soon. Selected ships will be equipped with Expendable Bathy-Thermographs (XBT) to enable them to monitor the varying heat storage in the ocean down to the thermocline. Anchored buoys can provide the same information as XBT-equipped commercial ships and will have the advantage of delivery data for long time-series at fixed locations. The buoys that can be permanently fi- nanced should preferably be placed to fill the big gaps between fre- quented shipping lanes. Also, their locations should be selected where ocean temperatures are likely to vary significantly, for instance along the equator. Infrared radiometers on satellites can be adjusted to record sea tem- perature in cloud-free areas, but the accuracy of such measurements can- not quite compare with careful ship- or buoy-based observations. The great contributions of the satellites to tropical studies are — presently and in the future — the TV-mapping of cloud distribution, the temperature measurements of the top surface of cloud, and, under favorable condi- tions, the movement of individual clouds and cloud clusters. Fixed installations on tropical is- lands will continue to be important for research on ocean-atmosphere in- teraction. Aerological soundings, in- cluding upper wind measurements, are best done from islands; moreover, fundamental measurements like the time variations of the topography of ocean level can only be done with a network of island-based tide gauges. The latter job does not call for very expensive equipment, and the tide gauges can be serviced as part-time work by trained islanders; the aerological work, on the other hand, calls for a technologically skilled staff on permanent duty. Replacements for Canton Island as an aerological observatory would be relatively expensive, but yet cheaper than was Canton, if islands with stable native population were selected for observatory sites. The two British islands of Tarawa (l°2l'N. 172°56'E.) and Christmas (1°59'N. 157°29'W.) would be ideal choices. Mathematical Modeling — A crude modeling of an asymptotically ap- proached "steady state" of an equa- torial ocean exposed to the stress of constant easterly winds has been pro- duced by Bryan, of the Geophysical Fluid Dynamics Laboratory, NOAA. A corresponding, quickly adjusting atmospheric model of the equatorial circulation, such as observed over the Pacific, was described in 1969 by Manabe, also of the Princeton NOAA team. Presumably, the ocean and atmos- pheric models can soon be joined for a simulation of the equatorial air- sea rhythms. Even without mathe- matical formulation, the rhythm can be crudely visualized to operate as follows: The cooling phase of the rhythm begins when the equatorial easterlies of the eastern Pacific start increasing and thereby start intensifying the upwelling. This increases the tem- perature deficit of the eastern end of the oceanic equatorial belt com- pared to its western end. The asso- ciated feedback upon the atmosphere shows up in an increased east-west temperature contrast, which produces an increment of kinetic energy in the equatorial atmospheric circula- tion. This, in turn, feeds back into 87 PART IV — DYNAMICS OF THE ATMOSPHERE-OCEAN SYSTEM increasing upwelling and ocean-cool- ing over an increasing area. A corresponding chain reaction can he visualized for the phase of the rhythm characterized by decreasing easterly winds, decreasing upwelling, and increasing equatorial ocean warming. Hence, a slow vacillation between the two extreme phases of equatorial atmospheric circulation, rather than a stable steady-state equatorial circulation, becomes the most likely pattern. Simulation experiments are pres- ently being planned on a global basis, encompassing both ocean and at- mosphere; they will bring more pre- cise reasoning into the explanation of the equatorial air-sea rhythms and, hopefully, into the interpretation of their teleconnections outside the tropics. Both the Princeton team, un- der Smagorinsky, and the team at the University of California, at Los Angeles, under Mintz and Arakawa, are progressing toward that goal. Requirements for Scientific Activity Continued empirical study of the tropical air-sea rhythms, in past and in real-time records, should accom- pany and support modeling efforts of theoretical teams. The knowledge gained on tropical air-sea rhythms and their extratropical teleconnec- tions so far rests on the study of only a limited number of case his- tories. Much more can be learned by studying the whole sequence of years 1950-67, during which Canton Island was available as an indicator of the air-sea rhythms. These years include the International Geophysical Year period, which happened to exhibit some extreme climatic anomalies and also had better-than-normal global data coverage. Such investigations are relatively cheap. The main expense goes into the plotting and analysis of world maps of monthly climatic anomalies in several levels up to the tropopause. Such a system of climatic anomaly maps would be the empirical tool for tracking the mechanism of the tele- connections. Liaison with EASTRO- PAC and other post-1950 Pacific tropical oceanographic research would become a natural outgrowth of the "historical" study. The 1970's is to be the era of the International Decade of Ocean Ex- ploration (IDOE) as well as that of the Global Atmospheric Research Program (GARP). The study of trop- ical air-sea rhythms belongs within the scope of both of these worldwide research enterprises and, indeed, will serve to tie the two together. The ultimate goal of IDOE-plus-GARP should be to model the atmosphere and the world oceans into one com- prehensive system suitable for elec- tronic integration. That endeavor should produce meaningful progress toward climatic forecasting by the end of the 1970's. 88 2. ATMOSPHERIC CIRCULATION Modeling the Global Atmospheric Circulation An understanding of the structure and variability of the global atmos- pheric circulation requires a knowl- edge of: 1. The quality and quantity of radiation coming from the sun. 2. The atmospheric constituents — not only the massive ones, but also such thermodynamically active components as water va- por, carbon dioxide, ozone, and clouds as well as other partic- ulates. Furthermore, one must understand the process by which these constituents react with the circulations and their radiative properties — i.e., ab- sorption, transmission, scatter- ing, and reflection. 3. The processes by which the atmosphere interacts with its lower boundary in the trans- mission of momentum, heat, and water substance over land as well as sea surfaces. The behavior of the atmosphere cannot be considered independ- ent of its lower boundary be- yond a few days. In turn, the lower boundary can react sig- nificantly. Even the surface layers of the oceans have im- portant reaction times of less than a week, while the deeper ocean comes into play over longer periods. Hence, the evolution of the atmospheric circulation over long periods requires consideration of a dy- namical system whose lower boundary is below the earth's surface. 4. The interactions of the large- scale motions of the atmos- phere with the variety of smaller-scale motions normally present. If these smaller scales have energy sources of their own, as is the case in the at- mosphere, the nature of the interactions will be consider- ably complicated. In principle, mathematical models embodying precise statements of the component physical elements and their interactions provide the means for numerically simulating the nat- ural evolution of the large-scale at- mosphere and its constituents. Suc- cessful modeling would have potential applications in a number of areas: long-range forecasting; determination of the large-scale, long-term disper- sion of man-made pollutants; the interaction of these pollutants in in- advertently altering climate; the in- fluence of intentionally tampering with boundary conditions to arti- ficially modify the climate equilib- rium. No doubt there are a variety of other applications of a simulation capability to problems that may not yet be evident. Current Status Efforts to model the large-scale atmosphere and to simulate its be- havior numerically began more than twenty years ago. As additional re- search groups and institutions in the United States and elsewhere became involved, steady advances in model sophistication followed. These came from refinements in numerical meth- ods as well as from improved formu- lations of the component processes. Today's multi-level models account for a variety of interacting influences and processes: large-scale topographic variations; thermal differences be- tween continents and oceans; varia- tions in roughness characteristics; radiative transfer as a function of an arbitrary distribution of radiatively active constituents; large-scale phase changes of water substance in the precipitation process; interactions with small-scale, convectively un- stable motions; the thermal conse- quences of variable water storage in the soil; and the consequences of snow-covered surfaces on the heat balance. More recently, combined models have taken into account the mutual interaction of the atmosphere and ocean, including the formation and transport of sea-ice. Although many of these elements are rather crudely formulated as cogs in the total model, it has been pos- sible to simulate with increasing detail the characteristics of the observed climate — not only the global wind system and temperature distribution from the earth's surface to the mid- stratosphere, but also the precipita- tion regimes and their role in forming the deserts and major river basins of the world. Attention is beginning to be given to the simulation of climatic response to the annual radia- tion cycle. Detailed analyses of such simula- tions in terms of the flow and trans- formation of energy from the primary solar source to the ultimate viscous sink show encouragingly good agree- ment with corresponding analyses of observed atmospheric data. Such models have also been applied to observationally specified atmospheric states in tests of transient predict- ability. Even within the severe limita- tions of the models, the data, and the computational inadequacies, it has been possible to simulate and verify 89 PART IV — DYNAMICS OF THE ATMOSPHERE-OCEAN SYSTEM large-scale atmospheric evolutions of the order of a week. These advances give promise that, as known deficien- cies are systematically removed, the practical level of the large-scale pre- dictability of the atmosphere can converge on a theoretical determin- istic limitation of several weeks. Models have also been used in some, more limited applications. For example, an attempt was made to simulate the long-term, large-scale dispersion of inert tracing material, such as radioactive tungsten, which had been released at an instantaneous source in the lower equatorial tropos- phere. The results were surprisingly good. Only limited attempts have been made to apply extant models to test the sensitivity of climate to small external influences. The reason is that one normally seeks to detect departures from fairly delicately bal- anced states. It is often beyond the current level of capability to simulate an abnormal response that is com- parable in magnitude to the natural variability noise level. Observational Problems The present large-scale data base is essentially dictated by the extent of the operational networks created by the weather forecast services of the world. The existing network is hardly adequate to define the north- ern-hemisphere extratropical atmos- phere; it is completely inadequate in the southern hemisphere and in the equatorial tropics. For example, there are only 50 radiosonde stations in the southern hemisphere in contrast to approximately 500 in the northern. The main difficulties arise from the large expanses of open ocean which, by conventional methods, impede de- termination of the large-scale com- ponents of atmospheric structure responsible for the major energy transformations. This critical defi- ciency in the global observational data store makes it difficult to define the variability of the atmosphere in enough detail to discern systematic theoretical deficiencies. Furthermore, the data are inadequate for the spec- ification of initial conditions in the calculation of long-range forecasts. Recent dramatic advances in in- frared spectroscopy from satellites promise significant strides in defining the state of the extratropical atmo- sphere virtually independent of loca- tion. (See Figure IV-6) However, the motions of the equatorial tropical at- mosphere lack strong rotational cou- pling, making the observational prob- lem there more acute. Independent wind determinations may be needed as well as the information supplied by a Nimbus 3 (SIRS sensor) type satel- lite. It is not yet known to what ex- tent balloon-borne instrumentation or measurements from ocean buoys will be needed to augment satellite obser- vations, especially in the lower tropos- phere. This will depend on just how strongly the variable character- istics of the atmosphere are coupled. A more precise knowledge would per- mit relaxing observational require- ments for an adequate definition of its structure. Figure IV-6 — SIRS SOUNDING T 5 Id (T to UJ 1/4 is sufficient for stability, and Ri ^ 1/4 is neces- sary, but not sufficient, for instability. The entire process has been dem- onstrated by Thorpe in laboratory fluid experiments and by Woods in thin, hydrostatically stable sheets in the summer thermocline of the Medi- terranean Sea. Both of these experi- ments show the development of beau- tifully formed billows, or K-H waves which roll up into vortices and finally break. And both demonstrate the gen- eral validity of the critical Ri sC 1/4. Evidence from tlie AtmospJiere — Ludlam has observed the existence of the K-H instability mechanism in the atmosphere by the presence of billow clouds, but only rarely are the com- bination of cloud and stability con- ditions just right to produce the lovely roll vortices in the clouds that are seen in the laboratory and the sea. The observation of their com- mon presence in the atmosphere has awaited the use of ultrasensitive ra- dars capable of detecting the weak perturbations in refractive index (due to temperature or humidity perturba- tions) which mark sharp inversions. Using three powerful radars at Wal- lops Island, Virginia, Atlas and his colleagues first reported the radar de- tection of clear air turbulence at the tropopause; Hicks, Angell, Hardy, and others have reported K-H waves and turbulence in clear air layers marked by static stability, large wind shear, and small Richardson number. Undoubtedly the most striking evi- dence of the K-H process as a cause of WIT, and of its common occur- rence at interval fronts, are the ob- servations made possible by the use of a unique new ultrasensitive FM-CW (Frequency Modulated Continuous Wave) microwave radar at the Naval Electronics Laboratory Center, San Diego. This radar is capable of one- meter vertical resolution, roiij; hundredfold increase over that pre- viously available with radars of com- parable sensitivity. With this new tool, it has been reported that K-H waves are a virtually ubiquitous fea- ture of the marine inversion over San Diego at altitudes up to about one kilometer. Indeed, the atmospheric K-H waves observed in this manner are commonly as beautiful in form as those produced in the laboratory and observed in the sea. (See Figure IV- 10) It is worth noting that the unex- pectedly classical form of the waves, and their great frequency of occur- rence within the marine inversion, recommends the southwest coast of the United States as an atmospheric laboratory for studies of WIT. What the Data Show — The fact that the observed K-H waves are fre- quently restricted to exceedingly thin layers, sometimes only a few meters in depth, and rarely with amplitudes as large as 100 meters, explains why the previously available high-sensi- tivity radars of poor resolution could not identify them. In other words, the K-H wave structure was simply too small to be seen and the echoes appeared merely as thin, smooth lay- ers marking the base of the inversion. The new data also indicate that, though K-H wave activity may be in progress, the associated turbulence will not be intense unless the waves grow to large amplitude prior to breaking. This has been demon- strated by the erratic perturbations of the height of the radar-detected layer, indicative of moderate turbulence, which resulted from the breaking of K-H waves of 75-meter amplitude. In general, waves of significantly smaller amplitude appear not to pro- duce appreciable turbulence. Work now in progress shows that the turbulent kinetic energy following the breaking of the roll vortex of a K-H wave is directly proportional to the kinetic energy of the vortex im- 109 PART IV — DYNAMICS OF THE ATMOSPHERE-OCEAN SYSTEM Figure IV-10 — WAVES AND TURBULENCE IN THE CLEAR ATMOSPHERE Height (m) 400 - 300 - 200 1920 1930 TIME (PDT) AUGUST 6, 1969 (Illustration Courtesy of the American Geophysical Union ) Radar echoes from the clear atmosphere reveal a group of amplifying and breaking waves in the low-level temperature inversion at San Diego, California, as observed with a special FM-CW radar. Waves are triggered by the sharp change of wind speed across the interface between the cool, moist marine layer and the warmer, drier air aloft. They move through the radar beam at the speed of the wind at their mean height, about 4 knots, so that crests appear at succes- sive stages of development. In the second wave at 1919 PDT cooler air from the wave peak drops rapidly as the breaking begins. By 1929 PDT the layer has become fully turbulent, and the radar echo subsequently weakens. Note, too, the secondary waves near the crests at 1919.5, 1922, and 1926 PDT; these secondary waves give rise to microscale turbu- lence, which causes the echo layers to be detected. The resulting turbulence would be weak, as detected by an air- craft. Waves of this type occur regularly in the low-level inversion, and are believed to be similar to those which cause the severe turbulence occasionally encountered by jet aircraft at high altitude. mediately prior to breaking. The r.m.s. velocity of a vortex, Vrms = 0.707 Aoj = 0.707 A(tV/(z) (2) where A is the amplitude of the roll or wave, to its angular rotation rate or vorticity, and cV/cz the wind shear, thus provides a simple estimate of the expected turbulence; prelimi- nary tests support this hypothesis. Moreover, it is of particular interest that the high-resolution radar data provide direct measures of A and its rate of growth as well as of 5V/?z, the shear. Similarly, the turbulence intensity may be deducted from the r.m.s. perturbations in the echo-layer height subsequent to breaking. (As yet, the inherent doppler capability of the FM-CW radar, which would pro- vide direct measurements of both vertical motion and roll vorticity, has not been implemented.) Unresolved Problems — If Equa- tion (2) is validated by experiments now in progress, we may contemplate the prediction of WIT from measure- ments and predictions of maximum wave amplitude and shear. But this assumes that we shall be able to pre- dict the latter. At this writing, the relationship of the maximum wave amplitude to the thermal and wind structure of the environment is not understood. Present K-H wave the- ory is limited to small-amplitude waves and their initial growth rates; clearly, the theory needs to be ex- tended to finite-amplitude waves. But rapid progress is more likely to come from experiments in the real atmos- phere, such as those already men- tioned, which involve somewhat more complex wind and temperature pro- files and interactions than are likely to be tractable in finite-amplitude theoretical models. In this regard, it should also be noted that the critical Richardson number, Ri,- < V-i, which might be regarded as a predictor of WIT, refers only to the initial growth stage of K-H instability. Since the high-reso- lution radar shows breaking K-H waves with amplitudes as small as 5 meters (with negligible resulting tur- bulence) and as large as 100 meters (with appreciable turbulence), a seri- ous question is raised as to the verti- cal scales over which thermal stabil- ity and shear — and so Ri — need to be measured. Surely, the present data imply that Ri must be observed on scales of a meter or less to account for the small-amplitude waves. But it is not so clear that measurements with resolution of 10 to 100 meters or more, such as those available from present-day radiosondes, would be adequate to predict the occurrence of larger-amplitude waves. What, for 110 CLEAR \ . , lENCE example, happens to a growing un- stable wave in a thin stratum when it reaches a dynamically stable layer in which Ri is significantly greater than Vi ? We do not know. This is one of many important questions that needs to be answered by further re- search. Other aspects of the new radar ob- servations that are relevant to flight safety as well as to aircraft investiga- tions of WIT and to its predictability, are: (a) the sharp vertical gradations in turbulence intensity (i.e., some- times the turbulence is restricted to a stratum no more than a few tens of meters thick) and (b) the inter- mittancy of K-H waves and turbu- lence. It is not surprising that one air- craft experiences significant turbu- lence while the next one encounters none in the same region. While the radar observations demonstrate that the base of the inversion and subsidi- ary sheets within it are the seat of K-H wave activity, their breaking is self-destructive in that the shear and stability to which they owed their origin are decreased, and Ri thus in- creased above its critical level. Ac- cordingly, the breaking action acts as an escape valve to release the pressure for K-H activity, and turns the waves and turbulence off. On the other hand, the larger-scale atmospheric processes work to restore the initial conditions, and new K-H waves are triggered. All this speaks to the difficult ques- tions of aircraft experiments directed to observing the initial conditions for WIT, the energy budget involved, and, indeed, its entire life cycle. Pre- cisely where and when should the measurements be made and how are they to be interpreted in the light of WIT's great spatial and temporal vari- ability? Clearly, such experiments should preferably be conducted si- multaneously with a radar capable of "seeing" the waves and turbulence di- rectly. Prospects for Prediction — The prior discussion raises serious doubts as to the ultimate achievement of pinpoint forecasts of WIT in either space or time. While one may expect, eventu- ally, to be able to predict the medium- to large-scale processes that work to develop and sharpen internal fronts and shear, many presently unobserv- able small-scale phenomena (gravity waves, orographic lifting and tilting, convective motions, and such) will operate to reduce Ri to its critical value locally and trigger wave activity here and there. Accordingly, while we may expect significant improve- ments in the predictability of the heights of internal surfaces, and thus in the heights at which WIT is likely, and probably in the predicted in- tensity as well, the actual forecast will probably remain a probabilistic one for many years to come. We should therefore direct a good share of our attention to the remote-probing tools that are capable of detecting both the internal surfaces and the occurrence of waves and turbulence. As in the case of radar detection of thunder- storms, such observations are likely to provide the best short-term predic- tions of WIT for the foreseeable fu- ture. Instrumentation for Detecting WIT Although we have spoken exten- sively of the capability of ultrasensi- tive high-resolution radar techniques in detecting WIT, a few additional re- marks need to be made concerning actual warning devices. Ground-Based Devices — High- resolution FM-CW microwave radar is an obvious candidate for this task. At present, however, it is limited to a detection range (based on over-all sensitivity in detecting clear air in- versions) of about 2 kilometers. An increase of range to 15 kilometers is attainable with available state-of-the- art components. This would accom- plish the detection of clear-air WIT throughout the depth of the tropo- sphere. A network of such st, across the nation, with fixed, ver- tically pointing antennas, is econom- ically feasible. Fortunately, the sig- nificant internal fronts at which WIT occurs are horizontally extensive, so that detection of waves and turbu- lence at one or more stations would indicate the layers affected and the likelihood of WIT at the same height (or interpolated height for sloping layers) in between stations. (Note that we emphasize the need for observa- tions with a high degree of vertical resolution, capable of detecting the suspect layers and measuring the amplitude and intensity of breaking waves.) Airborne Radar — With regard to the use of high-resolution FM-CW microwave radar on board aircraft for purposes of detecting and avoiding WIT along the flight path, the 15- kilometer range capability would be inadequate to provide sufficient warn- ing even if a high-gain antenna of the required dimensions (10' to 15' effec- tive diameter) could be accommodated in the aircraft. Moreover, since the vertical resolution in such a use-mode would correspond to that of the beam dimension rather than the available high-range resolution, the radar could not discern wave amplitude and heights with precision. However, the use of such a radar in both down- ward- and upward-looking directions (from large antennas fitted within the fuselage structure) does appear feas- ible. Clear-air WIT could then be avoided by detecting the heights of internal surfaces and K-H wave ac- tivity above and below flight level and assuming continuity of layer slope. Whether or not such a system should be adopted depends on cost/ benefit/risk ratios. The installation of a $100,000 radar seems warranted when aircraft carry more than 200 passengers. Certainly, it should be adopted for experimental purposes in connection with WIT research. The potential benefits of airborne high- resolution radar to both military and commercial aviation could then be better evaluated. Ill PART IV — DYNAMICS OF THE ATMOSPHERE-OCEAN SYSTEM High-Resolution Acoustic Radar is another candidate for clear-air WIT detection from ground-based stations. Such radars have detected thin inter- nal surfaces and stable and breaking wave activity to heights of 2 kilo- meters. The potential to reach 15 kilometers in the vertical direction can probably be realized, although the effect of strong winds aloft on the refraction of the acoustic beam re- mains an open question. Unfortu- nately, acoustic radar cannot be used on board fast-flying aircraft because of the slow speed of sound and the high acoustic noise levels. Future Teclmologx/ — Finally, a real hope still remains for the develop- ment of a coherent laser radar (or LIDAR) sufficiently sensitive to de- tect the small background concentra- tions of aerosols in the high tropos- phere and capable of measuring turbulence intensity through the dop- pler velocities. Although a theoretical feasibility study of such a device in 1966 indicated that the then available LIDARs could not accomplish the task, more recent developments in laser technology may now make such a system feasible. The National Aero- nautics and Space Administration is presently conducting research and de- velopment along these lines. A Note on Acoustic Monitoring As is well known, the propagation of sound waves through the atmos- phere is strongly affected by wind, temperature, and humidity. The pos- sibility therefore exists that measure- ments of the propagation of sound waves could be used to derive infor- mation on important meteorological parameters. The potential of these methods has been analyzed and some experimental results published. It has shown that acoustic echoes can readily be ob- tained from the atmospheric turbu- lence and temperature inhomogenei- ties always existing in the boundary layer of the atmosphere. The equip- ment required is relatively simple; it involves a radar-like system in which pulses of acoustic signal, usually about 1kHz in frequency, are radi- ated from an acoustic antenna, with echoes from the atmospheric structure obtained on the same or on a second acoustic antenna. This field of acoustic echo-sounding of the atmosphere is very new and appears to hold considerable promise for studies of the boundary layer of the atmosphere — i.e., the lowest sev- eral thousand feet. Specifically, re- search is now being undertaken to identify its usefulness for the quanti- tative remote measurement of wind, turbulence, humidity, and tempera- ture inhomogeneity. If, as expected, the technique is shown capable of measuring the structure of the bound- ary layer and the vertical profiles of these meteorological parameters, it will represent a major breakthrough in remote measurement of the atmos- phere, which should be of great value to meteorological observations and research. Its primary application is likely to be in the monitoring of meteorological parameters in urban and suburban areas, for use by air- pollution and aviation agencies. In addition, it is already providing the research worker with totally new in- sight into the detailed structure and processes controlling the atmospheric boundary layer in which we live. 112 5. URBAN EFFECTS ON WEATHER AND CLIMATE Urbanization and Weather For centuries, man has speculated that major battles, incantations, large fires, and, lately, atomic explosions could affect weather, although he made no serious scientific attempts to modify weather until 25 years ago. Except for a few localized projects involving precipitation increases and fog dissipation, however, man's in- tentional efforts have yet to pro- duce significant, recognized changes. Rather, the major means whereby man has affected weather have been inadvertent — through his urban en- vironment. Growing Awareness of the Problem As long ago as 700 years or more, London had achieved a size great enough to produce a recognizable ef- fect on its local weather, at least in terms of reduced visibility and in- creased temperature. Since major ur- ban areas became prevalent in Europe following the Industrial Revolution, Europeans have directed considerable scientific attention to this problem of urban-induced weather change. Now that major urban-industrial com- plexes exist in many countries, world- wide attention has grown rapidly, particularly in the United States, where the growth of megalopolitan areas during the past ten to thirty years has brought with it increasing public and scientific awareness of the degree and, in some cases, the seri- ousness of urban effects on weather. Recent studies documenting signif- icant urban-related precipitation in- creases in and downwind of Chicago, St. Louis, and industrial complexes in the state of Washington have further focused scientific and public attention on the urban-weather topic and its considerable potential. Certainly, even the casual observer is aware that visibility is more fre- quently restricted in a major urban complex than in rural areas, and that this has come from smoke, other con- taminants, increased fog, and their additive, smog. Most Americans are now aware that the temperature with- in a medium-to-large city is generally higher at any given time of the day or season than it is in rural areas. This temperature effect has been rec- ognized and measured for many years, since its measurement, at least at the surface, is relatively easy. "Heat islands" for many cities of various sizes have been well documented. Urban areas also act as an obstacle to decrease winds near the surface, to increase turbulence and vertical motions above cities, and to create, occasionally, a localized rural-urban circulation pattern. There have been enough descriptive studies, further- more, to reveal that many other weather conditions are also being changed, often dramatically, by urban complexes. Although available re- sults indicate that urban-induced weather changes are restricted to the cities and their immediate downwind areas and have little effect on macro- scale weather conditions, the "urban flood" and advent of the megalopolis could conceivably lead to significant weather changes over large down- wind regions. Value Judgments — The question of desirability of the weather changes wrought by urbanization has only re- cently been considered. The fact that many of the urban-induced changes have occurred gradually has not only made them difficult to measure quan- titatively within the natural variabil- ity of weather, but has also made them less obvious and, therefore, un- wittingly accepted by the urban dweller. Now that urbanization is nearly universal, American citizens have suddenly become aware of many of the urban-induced weather changes. In general, such changes as increased contaminants, higher warm- season temperatures, lower winds, added fog, increased thunder and hail, added snowfall, and decreased visibil- ity are considered undesirable. Cer- tain urban-related weather changes are desirable, however, including warmer winters and additional rain- fall to cleanse the air and to add water in downwind agricultural areas. In summary, then, with respect to their effects on weather, urban areas sometimes act as volcanoes, deserts, or irregular forests; as such, they pro- duce a wide variety of weather changes, at least on a local scale, and these changes can be classed as bene- ficial or detrimental depending on the locale and the interests involved. Type and Amount of Weather Change The changes in weather wrought by urbanization include all major surface weather conditions. The list of elements or conditions affected in- cludes the contaminants in the air, solar radiation, temperature, visibil- ity, humidity, wind speed and direc- tion, cloudiness, precipitation, atmos- pheric electricity, severe weather, and certain mesoscale synoptic weather features (e.g., it has been noted that the forward motion of fronts is re- tarded by urban areas). (See Figure IV-11) The degree of urban effect on any element will depend on the climate, 113 PART IV — DYNAMICS OF THE ATMOSPHERE-OCEAN SYSTEM Figure IV— 1 1 —WEATHER CHANGES RESULTING FROM URBANIZATION Cold Warm Annual season season (percent) (percent) (percent) Contaminants + 1000 +2000 +500 Solar Radiation -22 -34 -20 Temperature +3 + 10 +2 Humidity -6 -2 -8 Visibility -26 -34 -17 Fog + 60 + 100 +30 Wind Speed -25 -20 -30 Cloudiness +8 +5 +10 Rainfall + 11 + 13 + 11 Snowfall ±10 ±10 — Thunderstorms +8 +5 + 17 The table summarizes changes in surface weather conditions attributable to urban- ization. Changes are expressed as percent of rural conditions. nearness to major water bodies, on topographic features, and city size and components of the industrial complex. Furthermore, the amount of effect on the weather at any given time depends greatly on the season, day of the week, and time of day. Thus, urban solar radiation is de- creased much more in winter than summer; is decreased on weekdays; and is decreased more in the morning than in the afternoon. Temperature increases resulting from the heating of urban structures are much greater in winter than in summer; hence, the average urban air temperature in win- ter is 10 percent higher than that in rural areas, whereas in summer it is only 2 percent higher. However, ur- ban temperatures during certain sea- sons and weather conditions can be as much as 35 percent higher or 5 percent lower than nearby rural tem- peratures. It should be emphasized that op- posite types of changes in certain weather conditions are produced at different times. For example, fog is generally increased by urbanization, although certain types of fogs are ac- tually dissipated in large cities. Wind speeds are generally decreased, but they increase in some light wind con- ditions. Snowfall is generally in- creased by urban areas, but under certain conditions the city heat actu- ally melts the descending snow, trans- forming it into rain. Current Scientific Status Most studies of urban effects on weather have been descriptive and based on surface climatic data. Fur- thermore, only a few studies have at- tempted to investigate the causative factors and the physical processes in- volved in urban-produced weather changes. Without careful investiga- tions of the processes whereby urban conditions affect the weather, there is little hope for developing an adequate understanding and, hence, predictive capabilities. Data Base — The present data base is woefully inadequate for studies of most urban-affected weather ele- ments. Two-dimensional spatial de- scriptions of urban effects on weather elements are now adequate only for temperature patterns. Data for weather changes in the vertical are totally inadequate for temperature as well as for all other weather elements. Descriptive types of urban-weather studies based on existing historical records tend to be seriously limited in their spatial information. For instance, studies of urban-rural fog differences have typically been based on surface values from a point in the central city and one at the airport; although these may indicate a 30 percent difference, they fail to describe the horizontal distribution of fog over the urban or rural environs. Unfortunately, adequate descrip- tions of the surface weather changes are not available for most metropoli- tan areas of the United States. Study of the urban-weather relationships in the United States has been much more limited than that in Europe be- cause the surface weather-station net- works in and around American cities have been too sparse. Information useful for such practical problems as city planning can be developed for major U.S. metropolitan centers only on the basis of thorough comparative studies of data from denser urban- rural surface networks than currently exist around most American cities. Instrumentation — Satisfactory tools to perform needed monitoring and study of urban-induced weather changes are available. Major advances in the development of airborne equip- ment to measure meteorological vari- ables and aerosols provide the poten- tial for obtaining the vertical data measurements needed to develop time-dependent, three-dimen- sional descriptions of the weather ele- ments around cities. Field studies of the airflow and vertical temperature distributions at Cincinnati and Fort Wayne, Indiana, have used these new instruments and techniques in pio- neering research. Theory and Modeling — The basic theoretical knowledge and formulas exist for understanding the atmos- pheric chemistry and physics in- volved in urban-weather relation- ships. Ultimately, studies of the urban factors that affect weather elements will provide the inputs 114 URBAN EFFECTS ON ' IATE needed to model the urban-weather system. However, this will require three-dimensional, mesoscale numeri- cal models (not currently available) and computers (soon to be available) with the capacity to handle them. Practical Implications of Urban-Induced Weather Change Regional Planning — The factors that produce undesirable weather changes clearly need to be assessed, and hopefully minimized, in planning and building new urban areas and redeveloping old ones. For instance, the ability of large urban-industrial complexes to produce thunderstorms, heavy rains, and hailstorms in and downwind of the complexes has par- ticular importance in hydrologic de- sign for urban storm drainage and in agricultural planning. Pollution — Knowledge of the urban-induced wind and rainfall changes apt to occur with various weather conditions is also required for determining whether these changes will materially affect pollu- tion levels. The generally expected decrease in winds and poorer ventila- tion are certainly undesirable, but ur- ban-increased rainfall is beneficial in this connection. Such knowledge would also help in improving local forecasting, thus enabling man to do better planning of his outdoor ac- tivities. Weather Modification — Study of the exact causes of various urban- produced weather changes can also be expected to help man in his efforts to modify weather intentionally. In particular, the study of the conditions whereby urban complexes affect pre- cipitation processes could generate needed information about the weather conditions appropriate for seeding, the types and concentrations of ef- fective seeding materials, and poten- tial rainfall changes expected beyond the areas of known urban-related increases. Continuing disagreements over evaluation of man-made changes and the types of physical techniques and chemical agents of modification reveal the need for proper study of these aspects during urban field in- vestigations and analyses. The economic aspects of this prob- lem are hard to assess but are surely significant. Reduced visibility, more fog, and added snowfall directly and indirectly restrict human activity. The damages to health, property, and crops resulting from added contami- nants, less sunshine, higher tempera- tures, and less ventilation can be serious. National economic losses at- tributable to urban-induced weather changes are inestimable. Requirements for Scientific Activity The interactions of urban-produced weather changes with such matters as agriculture and hydrology, and with ecology, are only partly understood, since the inadvertent aberrations are frequently within the limits of natural variability of weather. For instance, the increase in crop yields resulting from urban-increased rainfall could be easily and accurately assessed, whereas the effect on crop yields of increased deposition of urban con- taminants into soils cannot currently be assessed without special studies. Our knowledge and understanding of the interactions of weather changes with man and society are almost totally lacking. The legal and social ramifications are barely understood, although the threats of damage to property, crops, health, and safety from such changes as increased con- taminants, more fog, less sunshine, and higher temperatures are now clear. Certainly, the responses to inadvertent weather changes provide an opportunity to study and assess potential human reaction to planned weather modification. The only means of fully assessing the urban- modification effect of each weather element in a given locale, however, is to measure all elements in three dimensions. Adequate measurement and under- standing of the interactions between urban factors and atmospheric con- ditions that produce, for example, a 10 percent rainfall increase in one urban complex should lead to rea- sonably accurate predictions of the precipitation changes in most com- parable cities where routine measure- ments of the urban factors exist or could easily be performed. Indeed, major projects to study the urban conditions that change weather ele- ments are sorely needed at several cities, each of which should be repre- sentative of basically different North American climates and urban com- plexes so that the results could be extrapolated to other cities. A min- imum national effort would consist of a thorough field project in one city that is representative in size and climate of several others. Such a project would be more meaningful if relevant interdiscipli- nary projects involving the physical and social sciences were conducted simultaneously. To achieve meaningful, three- dimensional measurements of weather and urban conditions will require marshalling of instrumentation and scientific effort to create dense net- works of surface instruments heavily supplemented by vertical measure- ments obtained by aircraft, balloons, and remote probing devices. The scientific skills, personnel, and fa- cilities necessary to explain and pre- dict most facets of this topic exist, but they have yet to be focused on it. Answers exist in relation to sev- eral basic questions concerning the urban-weather topic, but more con- centrated study is needed in the next five years. No serious effort has been made to describe the interac- tion between urban-induced weather changes and man, and this, too, is urgently needed. If performed, these studies should provide information adequate to modify some of the un- desirable weather changes within ten years. 115 PART IV — DYNAMICS OF THE ATMOSPHERE-OCEAN SYSTEM The Influence of Urban Growth on Local and Mesoscale Weather The fact that large human settle- ments change the atmospheric con- ditions in their immediate vicinity has been recognized for over a cen- tury. Up to very recently, however, it was considered that these influences were strictly local in character. Anal- ysis in depth has shown that this may not be the case at all and that urban influences on the atmosphere may well reach considerably beyond the urban confines. The causes for effects of towns on weather and climate are easily traced. First, human activities, especially combustion processes, produce heat. In some cities in northern latitudes during the winter this added energy may be a sizable fraction of the solar energy impinging on the same area. In recent years, airconditioning has also been adding heat to the air in summer by dumping the excessive indoor heat into the surrounding at- mosphere. The energy balance is further al- tered because urban surfaces replace vegetation of low heat capacity and heat conductivity with stony surfaces of high heat capacity and heat con- ductivity. These same urban sur- faces also alter the water balance. Rain runs off rapidly, diminishing the natural system of evaporation and evapotranspiration, not only fur- ther altering the energy balance by reducing evaporative cooling but also throwing great burdens on drainage and runoff systems at times of intense precipitation. Compact areas of buildings and dwellings also alter the natural air flow. They create considerable aero- dynamic roughness. This may cause changes in the low-level wind profiles up to several thousand feet in the atmosphere. Most important, probably, is the effect of cities on atmospheric com- position, not only locally but even for many dozens, if not hundreds, of miles downwind. Literally hundreds of different chemical compounds from industrial and combustion processes are blown into the atmosphere. The blind faith of the past trusted that friendly air currents would dilute and dispose of them harmlessly. Yet many of these admixtures have be- come semi-permanent residents of the atmosphere, where they undergo fur- ther chemical change through the im- pact of solar radiation and by inter- action with the water vapor in the atmosphere. Meteorological Changes and their Consequences Many of the meteorological altera- tions in urban areas have been quan- titatively assessed. Most of them are universally agreed to. In enumerat- ing them we proceed from the sim- pler to the more complex and, almost in parallel, from the noncontrover- sial to the controversial aspects of the problem. The Water Balance — It is per- fectly obvious that, by replacing the naturally spongy vegetative surface with impervious roofs, parking lots, and streets, any falling rain will quickly run off. Indeed, urban drain- age systems are designed to carry the waters rapidly into streams and rivers. The consequence is that flood waters may gather more rapidly and, in case of excessive rainfalls, not only increase crests but also cause rapid flooding of low-lying districts in ur- ban areas. The lag time of flood runoff may be cut in half by the impervious areas. Heat Islands — The excess energy production of a city and its altered heat balance, because of changes in albedo and heat characteristics of the man-made surface, creates one of the most notable atmospheric changes in urban areas. It has been given the very descriptive label "heat island." This term designates a tem- perature excess that covers the urban area. It is most pronounced in the sectors of highest building and popu- lation concentrations; on calm, clear nights it can reach or even exceed 10 Farenheit compared with rural surroundings. (See Figure IV-12) Re- cent experiments have shown that a single block of buildings will produce a measurable heat-island effect. At the same time, the reduced evapora- tion caused by rapid runoff and re- duced vegetation as well as this tem- perature increase reduces the relative humidity at the surface. Wind Circulation — The previously mentioned increase in surface rough- ness causes decreased wind speed at the surface. The heat island also induces wind convergence toward the urban area. In daytime, the highly overheated roof and black-top sur- faces create convective updrafts, es- pecially in summer. The updrafts induce a higher degree of cloudiness over the city and contribute to the release of showers over the city. At night, inversions of temperature form over the rural and suburban areas while temperature-lapse con- ditions continue in a shallow layer over the city core. This temperature distribution induces a closed circu- lation system within a metropolitan area, which in turn contributes to concentrations rather than dispersion of pollutants when the general wind circulation is weak. Solar Radiation — Pollutants act in an important way on the incoming solar radiation. The aerosol absorbs and scatters the solar radiation, af- fecting principally the shorter wave- lengths. This means that the long- wave ultraviolet radiation is radically weakened and its possible beneficial effects as killer of germs and activa- tor of vitamin D in the human skin 116 URBAN EFFECTS ON WEATHER AND CLIMATE Figure IV-12 — HEAT ISLAND EFFECT (Illustration Courtesy of the American Meteorological Society) The figure shows the isotherm pattern for 2320 PST on 4 April 1952 superimposed on an aerial photograph of San Francisco. The relation between the air tempera- ture measured 2 meters above the surface and urban development is evident. A temperature difference of 20°F. was observed on that calm, clear night between the densely built-up business district (foreground) and Golden Gate Park (left rear). are reduced or eliminated. At the same time, these actinic rays cause a large number of photochemical reactions in the welter of pollutants. Many of them lead to obnoxious sec- ondary products such as ozone, which irritates mucous membranes, and other equally undesirable products. They cause notable reduction in vis- ibility, which is not only aesthetically objectionable but often detrimental to aviation. Increased haze and fog frequency, compared with the natural environment, is a man-made effect, a fact that becomes impressive be- cause it is demonstrably reversible. In some cities (e.g., London) where the number of foggy days had grad- ually increased over the decades, a determined clean-up of domestic fuels and improved heating practices led to immediate reduction in the fog frequency. Precipitation — Much less certainty exists about both the local and more distant effects of city-created pol- lutants on precipitation. The already mentioned increased shower activity in summer has probably little or nothing to do with the pollutants. It is primarily a heat effect, with water-vapor release from combustion processes perhaps also playing a role. But we do have a few well-docu- mented wintertime cases when iso- lated snowfalls over major cities were obviously induced by active freezing nuclei, presumably produced by some industrial process. There is no in- contestable evidence that over-all winter precipitation over urban areas has increased, but most analyses agree that total precipitation over cities is about 5 percent to, at most, 10 percent greater than over rural environs, even if all possible oro- graphic effects are excluded. More spectacular increases observed in the neighborhood of some major indus- trial-pollution sources are probably the effect of sampling errors inherent in the common, inadequate rain- gauge measuring techniques. Even so, there is major concern about the very possible, if not al- 117 PART IV — DYNAMICS OF THE ATMOSPHERE-OCEAN SYSTEM ready probable, effects of city-pro- duced pollutants on precipitation processes. One of them can be caused by the high emission rates of minute lead particles from the tetraethyl-lead additive to gasoline. Some of these particles combine with iodine brought into the atmosphere primarily from oceanic sources to form lead-iodide. This compound has been shown to form very efficient and active freezing nuclei, which can trigger precipitation processes in only slightly sub-cooled cloud droplets. The lead particles are so small that they will stay in suspension for long distances and thus trigger precipita- tion at places far removed from the sources of the lead. Even more ominous could be the swamping of the atmosphere by condensation nu- clei. These are produced in urban areas in prodigious amounts in con- centrations surely two orders of mag- nitude higher than in uncontaminated air. There are literally hundreds of thousands of these nuclei in a cubic centimeter, and even the most hygro- scopic of them competes for the available moisture in the air. The more nuclei there are, the more likely it is that the cloud droplets that form will be very small because of the large number of competing centers around which condensation occurs. Small cloud droplets have more dif- ficulty in coalescing and forming rain than large droplets. Hence it is quite possible, although not proven beyond doubt, that in some urban areas or downwind from them a decrease in rainfall could occur. This is one of the effects requiring careful watch in future research. Atmosplieric Stagnation — When weather conditions favor slight winds and surface temperature inversions, air layers in metropolitan areas be- come veritable poison traps. These can lead to the well-known health- endangering pollution episodes. With a number of metropolitan areas in close proximity, a slight ventilation will waft pollutants into the next series of settlements within a few hours or days and aggravate the situ- ation there. This type of accumula- tion has not been adequately investi- gated either. But the whole area of the United States east of the Ap- palachians from northern Virginia to southern Maine may be affected by cumulative pollution effects. There are also other megalopolitan areas in the country that may need similar attention. Computer simulation of such atmospheric-stagnation periods has made some progress but is still severely restricted by the inadequacy of the mathematical models and the lack of sufficient actual observations. Many of the micrometeorological alterations brought about by urbani- zation have been well documented in a number of cities. They have re- cently been followed, stey by step, in a rural area that is in the process of becoming urbanized — the new town of Columbia, Maryland, where popu- lation density has increased from a few hundred to a few thousand in- habitants and will increase to a hun- dred thousand in the current decade. Many of the characteristic changes in temperature, wind, humidity, and runoff are already observable. This continuing study in a planned, grow- ing community may greatly further our knowledge of the micrometeoro- logical changes. Implications for Town Planning It is proper to ask whether we can turn this knowledge to use in future town planning and redevelopment of older cities. The answer is affirma- tive. Natural environments charac- teristically have a varied mosaic of microclimatic conditions, most of which are destroyed by urbanization. The detrimental effects are primarily introduced by compact construction with few interruptions, creating an essentially new surface of roofs at which energy interactions take place. In many urban areas, vegetation has been sharply diminished or even com- pletely eliminated. Reversal of this trend will bring about a desirably diversified pattern of microclimate. Two tall buildings with large green and park areas surrounding them are far preferable to the typical row house or walk-up slum configura- tion. The open construction charac- teristic of suburban areas has caused little climatic deterioration of the environment. Air pollution will remain a prob- lem. There is some merit in using tall stacks for the effluents from stationary sources. Appropriate loca- tion, predicated on the general re- gional airflow patterns, is indicated for industrial sources of pollutants. There is little substantive knowledge on possible amelioration of pollutants from mobile sources through highway routing, construction, elevation, or other engineering techniques. Con- trol at the source seems to offer the only tenable solution over the long run. Too little is yet known about the sinks of pollutants in urban areas, although shrubbery and insensitive plants seem to offer some help by intercepting particulates. Urban Effects on Weather — the Larger Scales The possibility that human activi- ties might be modifying large-scale weather patterns or even the global climate has received much publicity. The present state of atmospheric sci- ence does not allow either firm sup- port or confident refutation of any of the effects which have been pos- tulated. 118 URBAN EFFECTS ON WEATHER AND CLIMATE There is no doubt that cities modify their own weather by the local pro- duction of heat and addition of ma- terial to the atmosphere. "Material" includes water vapor (H_0) and car- bon dioxide (COu) as well as the gases and particulates commonly classed as pollutants. City tempera- tures exceed those of similarly ex- posed rural areas, particularly at night, but the most noticeable change is in the solar radiation reaching the ground, which is typically about 10 percent below that of upwind sur- roundings. In considering the extent to which effects on weather may overstep the city boundaries, it is convenient to look at three scales — local, regional, and global. "Local" refers to effects downwind of the city at distances up to about 100 miles; "regional" to subcontinental areas of the order of 1,000 square miles; and "global" to the whole world. Local Effects Local effects include deterioration of visibility and reduction of solar radiation, which are not in ques- tion. At 100 miles distance, in New England, one knows when the wind is blowing from New York City. This does not, in general, have repercus- sions on the other weather factors that are large enough to be estab- lished by examining weather records. If there are such effects they are small and probably lost in the general variance, although no very sophisti- cated search has been made — for example, among satellite cloud pic- tures — to verify that speculation. In two or three instances, it has been claimed that an increase of precipitation downwind of cities has been established. The best known example is at La Porte, Indiana, where an apparent considerable excess of precipitation over surrounding areas has been associated with industrial activity (particularly steel mills) in the Chicago and Gary, Indiana, areas. This seemed to be a clear-cut case, but the skill and/or objectivity of the one observer whose record estab- lished the effect has recently been questioned (with supporting evidence) by other climatologists. In the other cases that have been discussed, in- cluding recent claims of an increase of shower activity downwind of pulp plants in Washington state, the statis- tical evidence offered in support of the hypothesis of modification is less convincing than that for La Porte. Physically, there is doubt whether any precipitation increase that might occur would be an effect of cloud seeding by particulate pollutants or of the increased triggering of convec- tion by the heat and moisture sources of the city. The latter explanation is gaining favor. Regional Effects On the regional scale there is gen- eral agreement that atmospheric tur- bidity — a measure of the extinction of solar radiation — has increased over the past fifty years in western Europe and eastern North America, even in locations as remote from cities as can be found in these areas. Again, there is no indication that the reduction in solar radiation reach- ing the ground has had any effect on other weather elements. Such connections are extremely difficult to establish, for reasons which will be discussed later when we consider global effects. There is, however, one possible regional effect of pollution that is causing international concern, though it would not traditionally be con- sidered a "weather" phenomenon. This is the deposition in precipitation of pollutants transported hundreds of miles from their source, perhaps across international boundaries. The best-known case is the occurrence in Scandinavia of rainfall with an un- usual degree of acidity which has been attributed to the transport of pollutants emitted in Britain and Ger- many. A similar geographical and meteorological situation exists in the northeastern United States, where the situation might repay investigation. Persistently acidic rain or snow might have long-term effects on forest ecol- ogy and lead to reduced productivity in forest industries. The connection between the observation and its pre- sumed cause is simply the fact that no other explanation has been con- ceived. Statistical or physical links have not been demonstrated — in- deed, our current ignorance in the fields of atmospheric chemistry and microphysics precludes a convincing physical link. This is potentially one of the most serious of the currently unsolved scientific environmental problems. Global Effects The possible modification of cli- mate by industrial effluents has been under serious scientific discussion for more than thirty years and the ex- tent, nature, and intractability of the underlying problems is now becom- ing evident. It was postulated in the 1930's, and it is now clearly estab- lished, that the atmospheric COn con- tent is increasing as a result of com- bustion of fossil fuel. Radiative transfer calculations indicate that if the CO- content increases, and noth- ing else changes, temperature at the earth's surface will increase. No one ever seriously suggested that "noth- ing else changes," but it was noted that during the first forty years of this century recorded surface tem- peratures did increase. The connec- tion with CO:; increase was noted and extrapolated. There were prophecies of deluge following melting of the polar ice. However, by 1960 it was clear that surface temperatures were falling, and at the same time the continent-wide increase in turbidity was noted. (A global increase cannot be established because a network of suitable observations does not exist.) The obvious connection, on the hy- pothesis that solar radiation at the surface had decreased and nothing 119 PART IV — DYNAMICS OF THE ATMOSPHERE-OCEAN SYSTEM else had changed, was made. The extrapolators moved in, and there were prophecies of ice ages. Statistical and physical explana- tion of the problem of climatic change can be conceived, but each approach has fundamental difficulties. In the lirst case, existing series of climatic statistics based on instrumental read- ings are short — about 250 years is the longest reliable record. The stat- istics of these long series are not stationary; there is variance at the longest periods they cover. Historical and geological evidence indicates greater fluctuations of climate than the instrumental record. Statistics in- dicative of climate are not stationary. There can be no test of significance to separate climatic change that might be associated with man's activities from the "natural" changes associated perhaps with internal instabilities of the ocean-atmosphere system or per- haps with extraterrestrial change. The physical approach leads to sim- ilar conclusions, as Lorenz, in par- ticular, has pointed out. The equa- tions governing the ocean-atmosphere system certainly have innumerable solutions, and it may be that sets of these solutions exist with very dif- ferent statistics — i.e., that the earth may have many possible climates with its present atmospheric composi- tion and external forcing function. At most, changing the composition of the atmosphere (e.g., by adding CO2) might change the nature of the inevitable change of climate. Indicated Future Research Present activity is in two direc- tions— confirming and extending our knowledge of the changes of atmos- pheric composition due to industrial activity by monitoring programs, and developing physical models of the climate. This latter is one of the major scientific problems of the age, and we do not yet know whether it can be resolved to any useful extent. The requirement is for a model, sim- ilar to existing models of the global atmosphere and ocean but completely independent of any feature of the present climate. The most complex existing models incorporate a forcing function specified in terms of the cur- rent climatological cloud distribution and ocean surface temperature. The output of these models can, therefore, at best only be consistent with the existing climate. The requirement is for a model which will generate its own cloud distribution and ocean- surface temperatures. 120 PART V SEVERE STORMS 1. HURRICANES The Origin of Atlantic Hurricanes Atlantic hurricanes are uncommon events by comparison with the fre- quency of the storms that parade across the temperate latitudes of the United States each month. In terms of their deadly, destructive potential, however, they are, individually, the greatest storms on earth and the most important natural phenomena to affect the welfare of the United States. A single event may visit more than a billion dollars of damage and result in hundreds of lives lost, mainly due to drownings. In addition to carrying sustained winds that sometimes exceed 150 miles per hour and hurricane tides that may rise more than 20 feet above mean sea level, this massive atmospheric storm often carries with it families of tor- nadoes running ahead of the highest tides and strongest winds. For ex- ample, in Hurricane Beulah, which moved into the lower Texas coast in 1967, a total of 49 verified tor- nadoes was reported. The quest for a better understand- ing of the hurricane, for means of increasing the accuracy of forecasts, and, ultimately, for reducing the ex- tent of hazard has focused attention on the source regions of the seedling disturbances from which hurricanes grow, and on the environmental structure of the equatorial trough and the trade winds which control the forces promoting hurricane develop- ment. This quest has been greatly assisted by a new tool of observa- tion, the meteorological satellite, which maintains a continuous global surveillance of cloud groups produced by disturbances and storm systems. Surveillance and Prediction of Hurricane Seedlings On average, more than 100 hur- ricane seedlings move westward across the tropical Atlantic during the course of a hurricane season, June through November. These seed- lings are initially benign rain storms which move westward in the flow of the trade winds. Less than one-fourth of the seedlings develop circulation eddies with discrete centers of low pressure, and an average of only 10 per year intensify enough to sustain gale-force winds and earn a girl's name as a tropical storm. On aver- age, 6 of the 10 tropical storms reach hurricane intensity at some stage in their lifetime and 2 of these cross the U.S. coastline. For many years, meteorologists have known that some hurricanes seem to have their origin near the west coast of Africa. Not until the meteorological satellite provided daily information on storm systems around the globe, however, was it apparent not only that hurricane seedlings could be traced back to the African coastline in many instances, but also that they seemed to stem from a source region near the Abyssinian Plateau of eastern Africa. They march in great numbers across arid portions of Africa before reaching the Atlantic Ocean, where they begin ab- sorbing the moisture necessary to drive a vigorous storm system. A census of the hurricane seedlings that occurred in 1968 is presented in Figure V-l, which diagrams the sources and movement of disturb- ances and their evolution into tropi- cal storms. The parade of disturb- ances, mainly from Africa westward across the Atlantic and Caribbean, extends across Central America into the eastern Pacific. Approximately three-fourths of the eastern Pacific storms are spawned by seedlings whose origin is on the Atlantic side of Central America. It is noteworthy, however, that not all hurricanes form from seed- lings which had sources in Africa. Indeed, not all hurricanes form in the tropics. Almost every year one or two hurricanes develop from tem- perate-latitude systems. Typically, the trailing edge of an old worn-out cold front, while losing its temperature contrast, acquires a rich influx of moisture from the tropics. The proc- ess causes a circular storm to form and to develop the structural char- acter of the hurricane. Since this process frequently takes place in close proximity to a U.S. coastline, it poses a particularly challenging warning problem. Surveillance — The surveillance of hurricane seedlings and of hybrid disturbances that may become hurri- canes is done mainly by satellite cloud photography. Figure V-2, for example, shows a series of hurricane seedlings in the tropical Atlantic and a hurricane that is lashing the Texas coast — in this case, Hurricane Beu- lah, September 18, 1967. Two tropi- cal storms are also visible in the eastern Pacific Ocean. In such photo- graphs, the satellite looks down es- sentially on the exhaust product of the heat engine that generates the clouds. At present, inferences about the efficiency of the engine and the en- ergy that is being released must be drawn empirically and indirectly. However, second-generation satellites, and techniques for analyzing the movement of cloud segments from successive pictures, will soon provide more direct means of assessing the changes in horsepower that the heat engine develops. The tracking and prediction of hur- ricanes cannot be done with meteoro- 123 PART V — SEVERE STORMS Figure V-1 — A HISTORY OF HURRICANE SEEDLINGS The diagram shows areas of formation and decay of hurricane seedlings during 1968. Although the African continent appears to be important in the development of seedlings, some form in other parts of the Atlantic and the Caribbean. A hurri- cane may develop from any of the seedlings. Surveillance and tracking is much easier with satellites, but the question of why one seedling develops into a hurri- cane and another does not remains unanswered. TROPICAL STORMS Figure V-2 — HURRICANE BEULAH, 1967 BEULAH SEEDLINGS This cloud mosaic from September 18, 1967, shows Hurricane Beulah before it struck the Texas coast. The mosaic was compiled from pictures taken on eleven successive passes by the polar orbiting satellite, ESSA-3. Polar orbiting satellites pass over a given area twice per day, once during daylight hours and once at night. logical satellites alone. Judicious de- ployment of aircraft reconnaissance is also required to probe the storm center directly. The delicate balance of forces that usually exists within a hurricane and determines its destiny can be measured only by direct sens- ing, and the only practicable tool in sight for this purpose is the recon- naissance aircraft. Numerical Modeling — The prob- lem of modeling numerically the movement and development of hur- ricane seedlings, and especially the movement of full-blown hurricanes, is more complicated than that of modeling temperate-latitude frontal storms. The large-scale temperate- latitude storm derives its energy mainly from the sinking of large amounts of cold air, a process that can be described in terms of tem- perature contrasts on a scale of many hundreds of miles. The tropical storm, in contrast, develops in an environment where lateral tempera- ture constrasts are absent. 124 HURRICANES The release of energy in a devel- oping tropical storm involves a num- ber of links in a chain of actions, each of which must unfold in a timely and effective manner if the storm is to develop. First, the environment must be structured to support the spin that tries to develop locally in the wind circulation when pressure first begins to fall. Second, the en- vironmental winds must be able to distribute systematically the heat re- leased by the large cumulus clouds that spring up near the area of max- imum spin. It is the systematic dis- tribution of this heat, not its release per se, which generates fresh kinetic energy for intensification of the storm system. As the tropical storm intensifies further and approaches hurricane force, the system depends uniquely on a continuous flow of heat energy from the sea to the air. These proc- esses involve a subtle interaction be- tween the scales of motion charac- teristic of temperate-latitude storms and those characteristic of cumulus clouds only a few miles in diameter. This interaction is difficult to model, as is the flow of heat energy from the sea to the air. The primary purpose of project BOMEX (Barbados Ocean- ographic and Meteorological Experi- ment) conducted from May through July of 1969, was to gain better understanding of the exchange proc- esses across the ocean/atmosphere interface. The modeling problem, especially in connection with the tracking of undeveloped disturbances, is further complicated by the fact that in the tropics there is essentially a two- layer atmosphere, with disturbances in the lower layer sometimes travel- ing in a direction opposite to those in the upper layer. Because of all these complications, no model yet exists that can predict in real-time the moment and develop- ment of hurricane seedlings. A num- ber of diagnostic models have been produced which seem to simulate, in a research environment, many of the physical processes that occur during this development and that charac- terize the behavior of the full-grown hurricane. However, forecasting pro- cedures for tropical disturbances and storm systems still depend primarily on the identification, description, tracking, and extrapolation of the observed movement of the system. Present-Day Techniques — Fortu- nately, the digital computer provides the forecaster with rapid data- processing which enables him to as- sess the immediate behavior of storm systems and how this may reflect on the future movement and devel- opment potential. Because of the in- creasing use of machines for data- processing, it is now possible to make more extensive use of analogues to compare the present storm system with similar systems from historical records and thereby compute the probable movement and intensifica- tion to be expected. Figure V-3 is an example of one such method developed during 1969 at the National Hurricane Center. In this case, the computer is required to search historical records for all storms that were similarly located and whose characteristics were com- parable to the storm system for which a forecast must be made. From the historical record, a most-probable track for periods up to 72 hours is determined and a family of prob- ability ellipses is computed show- ing expected deviations from the most-probable track (50% and 25% probability areas). This family of ellipses is used to identify the area of the coastline to be alerted initially to the threat of a hurricane. Other more sophisticated tools, us- ing statistical screening techniques, are also used by the forecaster to guide his judgment in predicting hur- ricane movement. 105W Figure V-3 — PROBABILITY FORECASTS FOR HURRICANES 100W 95W 90W 85W 80W 75W 70W 35 N 30N 25 N 20N In this relatively crude warning technique, a computer searches historical data to find a hurricane situation with similar characteristics to the one under observation. It then prognosticates future positions for 12, 24, 36, 48, and 72 hours, as shown in the figure, based on the history of the earlier hurricane. The size of the proba- bility ellipses indicates the magnitude of error that is involved in the use of this technique. 125 PART V — SEVERE STORMS Development of still more sophis- ticated prediction models depends on a better means of observing the in- teractions between large and small scales of motion. The major emphasis of the Global Atmospheric Research Program's first tropical experiment, scheduled for the Atlantic Ocean in 1974, will be to describe and under- stand cloud clusters. The results of this investigation should provide valuable guidance in modeling the interaction between meso- and syn- optic-scale motions. For the imme- diate future, however, the emphasis will probably have to remain on development of numerical methods that will minimize errors in predict- ing tropical disturbances and storms. Unless vast resources are devoted to the problem, sophisticated prediction models are not apt to become avail- able in less than five to eight years, if then. The median error in predicting the landfall of hurricanes along a U.S. coastline continues to decrease slowly, although it varies from year to year. This progress is due not so much to advances in modeling hurricanes numerically as it is to the availability of better facilities to track and ob- serve disturbances at each stage of development and of modern tech- nology that provides rapid processing of data from the storm area and environment. These facilities permit us to apply diagnostic tools of rea- soning in an objective fashion, though we have only scratched the surface in the development of such tools. Apart from any progress that might be made in modeling the behavior of hurricanes, there is good reason to estimate that the median error for predicting hurricane movement near our coastlines, now about 110 nauti- cal miles for a 24-hour movement, can be reduced by 30 to 40 percent. This depends, however, on exploiting information from the meteorological satellite to obtain numbers — rather than impressions — concerning the physical character of the environment in which the hurricane or its seedling moves. Basic Understanding of the Hurricane System While much has been learned about the hurricane, its structure, and the energetics that cause a seed- ling disturbance to develop, there remain notable gaps in the funda- mental understanding of the hurri- cane system. The first is the puzzle of why so few hurricanes manage to develop from the abundance of seedlings that parade across the tropi- cal scene. Secondly, the hurricane is basically an unstable system varying in intensity from day to day and even from one six-hour period to the next, but the reasons for these varia- tions are not understood. The whole concept of weather modification in hurricanes may depend on a better understanding of the natural instabil- ities in this delicately balanced sys- tem. Answers to these questions will probably depend on a concerted pro- gram of field experimentation and numerical modeling. To pursue the problem only through numerical modeling is risky for the simple reason that, in so complex a system, the modeling problem becomes in- tractable unless there are extensive uses of approximations, parameteri- zations, and other mathematical sim- plifications which, while yielding in- teresting results, may only crudely simulate the real atmosphere. Ex- perience has shown that the best results come from a two-pronged program which, in step-wise fashion, produces a model for one facet of a development and then verifies the result of this simulation by field exploration in the real atmosphere. Prospects for Reducing the Hurricane Hazard Ideally, one would like to find some means to prevent all hurricane seed- lings from developing into severe storms while retaining the useful rainfall carried by these disturbances. Although many suggestions have been made for cloud-seeding or other cloud-modifying measures to curb the formation of hurricanes, none has comprised a physical hypothesis that has considered both the cloud proc- esses and the circulating properties of the cloud environment. It appears more and more likely that the formation of a hurricane is something of an accident of nature, at least with regard to the particular cluster of clouds in which the event occurs. In general, a storm center tends to form somewhere in an en- velope of rain clouds spread over hundreds of miles. But there is still no reliable means of predicting which particular cluster nature will pick to foster the growth of a storm center. Therefore, even if one knew precisely what modification techniques to ap- ply to a cluster of clouds (no more than 25 or 30 miles in diameter, for example) — and one does not know this yet — it would be impossible to know where to send the aircraft to conduct the seeding or take other preventive actions. Cloud Seeding: Project STORM- FURY — As for curbing the fury of the hurricane, it must be conceded that, at present, the only hope lies in identifying, and hopefully treading on, the "Achilles heel" of a delicately balanced storm system — its ability to release latent heat under certain circumstances. That is precisely what the Project STORMFURY hypothesis seeks to accomplish. While scientists do not yet fully agree on the benefits to be expected from systematically seeding hurri- canes or seeking in other ways to upset the balance of forces in the storm, those who have followed the STORMFURY experiments cannot help but be excited about the very encouraging results obtained in 1969 from Hurricane Debbie. If the same order of response from cloud seeding is obtained in one or two additional experiments, it will be possible to demonstrate beyond a reasonable 126 doubt that a significant reduction can be made in the destructive po- tential of hurricanes, including the damage due to hurricane tides, by strategic seeding of the eye wall. This is the most exciting prospect in all geophysical research and develop- ment, both because of the immediate potentialities for reducing property losses and saving lives in hurricanes and because the insight gained from this experiment should open the door to more far-reaching experiments aimed at modifying other threatening large-scale storms. A Report on Project STORMFURY: Problems in the Modification of Hurricanes Damage to property in the United States caused by hurricanes has been increasing steadily during this cen- tury. Hurricanes caused an average annual damage in the United States of $13 million between 1915 and 1924. By the period 1960 to 1969, this figure had soared to $432 million. Hurricane Betsy (1965) and Hurri- cane Camille (1969) each caused more than $1.4 billion in damage. Even after adjusting these values for the inflated cost of construction in recent years, there remains a 650 percent increase in the average annual cost of hurricane damage in less than 50 years. Since Americans are accelerat- ing construction of valuable buildings in areas exposed to hurricanes, these damage costs will probably continue to increase. The loss of life from hurricanes has been decreasing about as dra- matically as the damages have been increasing. This decrease in number of deaths can be attributed largely to improvements in hurricane warn- ing services and community prepared- ness programs. The reduction in loss of life is especially notable consider- ing that the population has been in- creasing in hurricane-vulnerable areas just as rapidly as the value of prop- erty. Figure V-4 illustrates the trends with time in damages and loss of life in the United States caused by hurricanes. When warnings are timely and accurate, lives can be saved by evacu- ating people to safe locations. Prop- erty damages can be reduced only by building hurricane-resistant struc- tures or by reducing the destructive potential of hurricanes. But the first solution may be quite expensive. Extreme destruction may result from any one of three different at- tributes of a hurricane: (a) the storm surge, associated ocean currents, and wave action along the coast; (b) the destructive wind; and (c) rain-created floods. The hurricane winds that Figure V-4 — HURRICANE LOSSES BY YEARS Millions of Dollars 16001 1400 1200 1000 800 600 400 200 DAMAGE ADJUSTED TO 1957-59 BASE DEATHS Number of Deaths 4000 - 3500 Hhn 3000 - 2500 2000 1500 1000 500 0"» "^ CT> ^=3- o~\ ^t at *=*■ ot ^" CT> i— i cm c\j co m ^3- m i/iiD ud Ot ^ Ot *=3" 0*1 — id m Kn iX3 iDoiDoinoiDomoui •HCNjfNjmro^-^miriiDUD oifficncncniTicriCTicricriai 0~i0~>O'lO">O"»O"»a">0">O'>O"l The bar graph shows the trends in loss of life and damage due to hurricanes. The damage figures have been adjusted to eliminate inflationary and other fluctuating trends in the cost of construction. 127 PART V — SEVERE STORMS sometimes approach 200 miles per hour may cause storm surges of 20 to 30 feet or so, the development of strong coastal currents which erode the beaches, and the onset of moun- tainous waves. Once the latter three elements are in being, they are far more destructive than the winds and are usually responsible for the greater damage. Their destructive power varies directly with the speed of the winds. Damage due to sea forces and to winds is concentrated along and near the seacoast; even the damage at- tributed to winds alone usually drops off drastically within a relatively few miles of the coast when a hurricane moves inland. Damage from rain- caused floods, on the other hand, may extend far into the interior and is particularly acute in mountainous regions traversed by the remnants of a hurricane. This is especially true in situations where rain-induced floods originate in mountains near the coast and arrive at the coastal plain before the ocean waters have receded. In view of the difficulty of building structures to resist all these destructive elements, efforts have lately concentrated on reducing the destructibility potential of hurricanes. If the present program for modi- fying hurricanes to reduce their in- tensity should prove effective, the potential benefit/cost ratio could be of the order of 100:1 or 1,000:1. It should be emphasized that the modifi- cation program has no intention of either "steering" or completely de- stroying hurricanes. The rainfall from hurricanes and tropical storms is an essential part of the water bud- get of many tropical and subtropical land areas, including the southeastern United States. The hope is to reduce a hurricane to a tropical storm by a reduction in the speed of the concen- trated ring of violent winds near the center, leaving the rainfall and total energy release of the over-all storm essentially unchanged. Details of the Project The groups active in Project STORMFURY, a joint effort of the U.S. Navy and the National Oceanic and Atmospheric Agency (NOAA), conducted experiments on hurricanes in 1961, 1963, and 1969. In each case, the objective was to reduce the maximum winds of the hurricane. The technique called for seeding a hurricane with silver iodide crystals in order to cause supercooled water drops to freeze and release their latent heat of fusion. In the earlier years, the experiments consisted of seeding a hurricane one time on each of two days. The results appeared favorable but were inconclusive, since the changes were of a magnitude that often occurs naturally in hurricanes. In August 1«60, the STORMFURY group seeded Hurricane Debbie five times in a period of eight hours on the 18th and 20th of the month, with no experiment on the 19th. Following the seedings, maximum winds at 12,000 feet decreased within six hours by 31 percent on the 18th and 15 percent on the 20th. The storm regained its original intensity on the 19th. While changes of this mag- nitude have happened in hurricanes on which there was no experiment, they have been quite rare. When one considers the entire sequence of events in 18-20 August, one can say that such a series of events has not happened in previous hurricanes more than one time in 40. Thus, while we cannot state that the Debbie experiments proved that we know how to modify hurricanes, the results were certainly very encouraging. Along with the experimental pro- gram, there has been an intensive effort to develop models which simu- late hurricanes. The best of these models now reproduce many features of a hurricane quite well. One devel- oped by Rosenthal has been used to simulate seeding experiments, includ- ing the one performed on Debbie. The STORMFURY experiment was simulated by adding heat at appro- priate radii at the 500 and 300 milli- bar levels (approximately 19,000 and 32,000 feet, respectively) over a pe- riod of ten hours. The amount of heat added was believed to be com- parable to the amount of latent heat that can be released by seeding a hurricane. Within six hours after cessation of the simulated seeding, the maximum winds at sea level decreased about 15 percent. The time-scale for the decrease in max- imum winds was roughly the same as that in the Debbie experiments. Evaluation of Results The net results of the various field experiments and the implications from modeling experiments give strong reason for believing that at least some degree of benefical modifi- cation was achieved in the Debbie experiments. Unfortunately, how- ever, we cannot say the matter is proved nor can we claim the results are statistically impressive at some high level of significance. The modeling results are most in- teresting and highly suggestive, but there are certain deficiencies in the model which require that one be cautious in interpreting them. First, a highly pragmatic parameterization of cumulus convection is used. Sub- stantial improvements in this area must await increased understanding of both cumulus convection and its interaction with larger scales of mo- tion. Second, the major simplifying assumption of circular symmetry used in the model precludes direct comparison between model calcula- tions and specific real tropical cy- clones. Real cyclones are strongly influenced by interaction with neigh- boring synoptic systems, and these vary markedly in character and in- tensity from day to day. When one looks at parameters other than the winds for further verification of seeding effect, either the data were not collected in Hur- ricane Debbie or insufficient data are 128 HURRICANES available from previous storms to provide a clear definition of the nat- ural variability of the parameter. These points can be illustrated by discussing the various measurements that should be made. The following are either assumed by the modification hypothesis or are implied by results from the modeling experiments: 1. In hurricane clouds, large quan- tities of water substance exist in the liquid state at tempera- tures lower than —4° centi- grade. 2. Introduction of silver iodide crystals into these supercooled clouds will cause the water droplets to freeze and release the latent heat of fusion. 3. If the heat is released in the annulus radially outward from the mass of relatively warm air in the center of the storm, it should cause a temperature change that will cause a reduc- tion in the maximum tempera- ture gradients in the hurricane. 4. A reduction in the mean tem- perature gradients must result hydrostatically in a reduction of the maximum pressure gradi- ent in the storm. 5. A reduction in the pressure gradients should cause a reduc- tion in the maximum winds in the storm. 6. The belt of maximum winds should migrate outward after the seeding has had time to affect the storm. This action presumably would be accom- panied by development of a larger eye, with the eye wall at a larger radius, or, possibly, a change in structure of the wall cloud. All of the above suggest certain measurements that should be made in the storm. If the changes in these parameters occur at the right time, in the right sequence, and with proper magnitudes, the cumulative evidence that the experiment was a success could be very convincing. Efforts were made to collect all of these data in Debbie. In some cases, however, the efforts were unsuccessful or the data do not permit conclusive deduc- tions. An aircraft was equipped to make measurements of the character and amount of water substance in the lower levels of the supercooled layer in Hurricane Debbie. While attempt- ing to make the first pass across the storm at the 20,000-foot level, a supercharger malfunctioned and the aircraft was no longer able to main- tain that high an altitude. There are, however, some qualitative observa- tions which suggest there was a change in character of the water substance from predominantly super- cooled water to a mixture of ice and water. These observations are not at the right level or of sufficient detail and quality to document incon- trovertibly that the seeding accom- plished a major transformation in the liquid-ice budget of the clouds. This should not be interpreted to mean that the seeding failed to accomplish the desired effect, however. There are just insufficient data to convince a skeptic that the effect was actually achieved. Very detailed and frequent obser- vations of the temperature, pressure, and winds were made along diameters across the hurricane at the 12,000- foot level. From these data we can compute changes with time in the parameters of their gradients at any point along the diameter. The changes in the maximum wind speed have already been mentioned. The changes observed in tempera- tures and temperature gradients are not conclusive enough to support the above hypotheses. On the other hand, if the release of latent heat was in the layers above 18,000 feet, one should not expect dramatic changes in the temperature and its gradient at 12,000 feet. We have in- adequate temperature measurements in the layer between 18,000 feet and 30,000 feet, since lack of properly instrumented aircraft precluded the acquisition of the type and quantity of data needed. Furthermore, results from the seeding simulation experi- ment conducted with the model sug- gested that the added heat is rapidly dispersed and dramatic changes in the temperatures are not likely to occur. The changes in the pressure and pressure gradients measured at 12,000 feet do give some support to the success of the seeding and some indi- cation that results conformed to the hypothesis. But the great amount of noise in the variations of this param- eter and lack of adequate knowledge concerning natural variations in hur- ricanes make it impossible to say the case is proved. Once again, the in- dications are positive but inconclu- sive. Intensive efforts were made to get continuous coverage of the structure of the storm by airborne radar and by the ATS-3 satellite. This was done with the hope that these data would reveal the nature and time of changes in the cloud structure that might be caused by the seeding. The radar pictures suggest that the eye size did become larger after the seedings; the changes in size even appeared to have a periodicity sim- ilar to that of the seedings: about an hour and a quarter after several of the seedings there was a rapid in- crease in the area encompassed by the wall cloud. One must be cautious, however, in placing too much emphasis on this evidence. The eye wall was pulsating during most of the time the STORM- FURY crews were monitoring it, so there were many changes in size, shape, and character of the eye be- fore, during, and after the seeding. There were also many problems with 129 PART V — SEVERE STORMS the data. No single radar monitored the storm during the entire seeding operation, and it was necessary to use various radars to obtain a con- tinuous time record of the eye area. After considering the many prob- lems of interrelating various radars, calibrating ranges, distortions, etc., one can only conclude that there is some evidence that the seeding did indeed affect the hurricane clouds around the eye in the manner hy- pothesized, but that the data are of such a heterogeneous nature as to be inconclusive in themselves. Pictures of Hurricane Debbie were taken by ATS-3 each day of the period, 17-21 August. Normally, processed pictures do not reveal much detail of the seeded areas. Although enhanced pictures were made along lines suggested by Fujita, they have not yet been developed. Work with a small sample of these pictures suggests that we will obtain some interesting information about changes in the cloud structure of the storm, though it is unlikely that these pictures will be adequate for determining with confidence whether the seeding had a major effect on the changes. Wind-field measurements did show that the radius of maximum winds increased following the seeding. Requirements for Future Activity The use of theoretical models to study the modification hypotheses was discussed in the previous section. Some deficiencies of the present mod- els were also mentioned. We should use the present models to learn as much as possible about the interac- tions and potential instabilities of hurricanes, but we should also con- tinue experiments to develop further information as to how well the mod- els simulate actual hurricanes. At best, they can do this only in a mean sense. We should also continue work to remove the restrictive assumptions; these relate to circular symmetry, interaction between the hurricane and synoptic-scale features in the environment, dynamics of cumulus clouds, and interactions between the hurricane scale of motion and circu- lations of smaller scale. The matter of parameterizing cumulus processes in the model must be re-examined and carefully compared with cumulus models and observations. A more closely spaced grid should be used in the eye-wall region. And, finally, the outer radial boundary (now at 440 km) should be moved outward and other outer boundary conditions investigated to make sure they are not determining or markedly affect- ing the solutions following the "seed- ing." When the field experiments are repeated, every effort should be made to obtain data that will permit veri- fying various steps related to the seeding hypotheses. These were dis- cussed in the preceding section. Fa- cilities and manpower are not avail- able at the present time to obtain all of these data. In summary, the present status of our scientific knowledge suggests quite strongly that techniques pres- ently available are adequate to achieve beneficial modification of mature hurricanes. Data from experi- ments and theoretical studies support each other, but in each case there are gaps in our knowledge which suggest we should be cautious in making extreme claims. What is clear is that we should repeat the Debbie- type experiments on other hurricanes as soon as possible to see if we can duplicate the Debbie decrease in wind speeds and to document details of the effects. We should continue our theoretical investigations to remove some of the limiting assumptions. With losses from hurricanes in the United States currently averaging over $400 million per year and loss of life still a threat, action should be taken as soon as possible. Since the prospects seem good that we can reduce the destructive power of hur- ricanes, the need for additional ex- periments becomes much more ur- gent. If present techniques are adequate for modifying a hurricane, it is quite likely that we can collect enough information during the next one or two years to justify application of the experiments to storms expected to affect the coastline. If present techniques are inadequate, we have several other approaches which should be explored. The time needed to develop and test better hypotheses or to improve and exploit the present hypotheses suggests that we should plan five to ten years ahead. The Scientific Basis of Project STORMFURY Project STORMFURY is concerned with the problem of devising ex- periments to modify hurricanes and tropical cyclones. Because the design and evaluation of such experiments depends essentially on understanding the structure and behavior of "nat- ural" hurricanes, the close associa- tion of the project with the National Hurricane Research Laboratory of the National Oceanic and Atmospheric Administration is appropriate. The impetus for such experiments arises primarily from the large potential benefits, in the form of reduced prop- erty damage and loss of life, which could be realized from relatively small modifications of the intensity or mo- tion of these storms. During the past decade, increased understanding of hurricanes, based on both descriptive and theoretical studies, has suggested at least two 130 HURRICANES possible avenues of achieving benefi- cial modification. Utilization of the approach with the sounder basis of scientific understanding has so far been precluded by logistic considera- tions. The second approach, which involves complex but feasible logis- tics, has been used in experiments on three hurricanes with encouraging but not yet definitive results even though the detailed physical basis for the approach is not completely understood. Present Scientific Status Special observational efforts and more intensive theoretical studies during the past twenty years have led to important advances in the understanding of the physics of hur- ricanes, but significant gaps remain to be filled. Preliminary efforts at constructing mathematical models of the hurricane have been encouraging, but serious defects remain. Data Base — For hurricanes in the mature stage and in dissipating stages over land, the descriptive data base is good in the qualitative sense. The principal data deficiencies consist of quantitative measurements of such items as: the distribution of water in all phases as a function of tem- perature in the storm; the fluxes of heat and water vapor from the sea to the air under the extreme condi- tions present in the hurricane; and the natural variability of various meteorological parameters in the inner regions of the hurricane as a function of time-scales ranging from an hour to a day or two. Basis for Modification — The most significant addition to our scientific knowledge of hurricanes in recent years has been the convergence of both theoreticians and empiricists on the concept that the hurricane is the complex result of the interaction of physical processes on several dis- tinctly different scales. It is now agreed that these storms, whose space-scale of a few hundred kilo- meters and lifetime of a few days typify the synoptic-scale of atmo- spheric systems, depend critically on microscale (1 to 10 meters) turbulent motions of the surface boundary layer for the addition of heat and water vapor from the sea surface, and on mesoscale convective clouds, pri- marily organized in the annular ring surrounding the eye, for release of the latent heat of water vapor as the primary driving mechanism of the storm. Furthermore, the combined processes on these scales are influ- enced by interactions with much larger scale systems of the atmos- phere. It is this dependence on microscale turbulence and mesoscale convection that has suggested the two avenues to modification. Reduction of the evaporation associated with the for- mer would certainly result in reduc- tion of hurricane intensity, but this approach to modification has been prevented by insurmountable logistic problems. Redistribution of the latent heat release associated with the latter through the use of cloud- seeding techniques shown to influ- ence the structure and dynamics of convective clouds is logistically feas- ible and has been employed in ex- periments on a small number of hurricanes. There are residual un- certainties and disagreements as to the correct seeding techniques and the interpretation of the experimental results. Theoretical models of the hurricane incorporating the various scales dis- cussed above with varying degrees of simplification have been developed. Results of computer simulations based on these models indicate qual- itative success in modeling the physi- cal processes responsible for the formation and maintenance of the hurricane. But significant quantita- tive uncertainties remain. Further- more, present models cannot con- tribute significantly to problems of hurricane motions. Interactions — Our present scien- tific knowledge and understanding of the interaction of hi other aspects of the atmospheric gen- eral circulation, with other environ- mental systems such as the ocean, and with man and society are qualita- tive and inadequate. For example, it is known that rainfall associated with hurricanes is often of consider- able economic benefit, but it can also lead to disastrous floods. We do not know how the atmospheric circula- tion would change if hurricanes did not exist. Nor is it decided who in society is to decide when and where hurricane modification should be at- tempted. Requirements for Scientific Activity Significant scientific controversy exists with respect to the following aspects of hurricane modification: 1. Can the effects of seeding ex- periments be unequivocally de- tected against the large natural variability of hurricanes? 2. How, exactly, does cloud seed- ing redistribute latent heat re- lease and how is this redistribu- tion responsible for decreases in hurricane intensity? 3. Are the present mathematical models and associated com- puter simulations of hurricanes sufficiently realistic to serve as indicators of differences in ex- pected behavior of natural and seeded hurricanes? 4. Are the amounts of super- cooled liquid water necessary if seeding techniques are to result in significant redistribu- tion of latent heat release ac- tually present in the correct portions of the storm, and is this water actually frozen by the seeding? The most urgently needed scien- tific advances fall into two categories: observations and theoretical model- 131 PART V — SEVERE STORMS ing. Observations are needed to document more thoroughly the nat- ural variability of hurricanes; to de- termine the distribution of water in all its phases in the inner portions of both natural storms and before, dur- ing, and after seeding in experimental storms; and to quantify further the interactions among physical processes on the various scales important to hurricanes. Theoretical models and associated computer simulations need: (a) to be improved in the way in which smaller-scale processes are treated implicitly through parameter- ized relationships; (b) to be gen- eralized such that the effects of in- ternal processes on the motion of the storm can be treated; and (c) to utilize improved observations as varying boundary and initial condi- tions for the models. Time-Scale — The urgency of sat- isfying these needs is undoubtedly relative. In terms of clarifying the scientific basis for Project STORM- FURY, the need is very urgent. To substantiate the encouraging, but inconclusive, results from past ex- perience and, thereby, provide a solid foundation for modification experi- ments on storms threatening inhab- ited coastlines, their importance can- not be overemphasized. These advances in scientific back- ground are needed within one to two years. Instrumentation and observa- tional platforms needed to fill most of the known gaps in the scientific data base for both natural and experi- mental hurricanes are available. Sim- ilarly, significant improvement in computer simulation is possible with existing computers. Legal Implications — The greatest potential policy problems associated with hurricane modification will arise from the legal questions that will be raised at both national and interna- tional levels when modification ex- periments are carried out on storms which shortly thereafter affect in- habited coastal regions or islands. When and if we are able to predict what will result from such modifica- tion attempts, who will make the decisions? A study of these problems is sorely needed. A Note on the Importance of Hurricanes Necessity Our understanding of the physical laws governing the behavior of the atmosphere has not advanced to the point where we can deduce from these laws that hurricanes, or any tropical circulation systems resem- bling hurricanes, must occur. It is just reaching the stage where we can deduce theoretically that systems of this sort may occur. Recent numeri- cal experiments aimed at simulating hurricanes have produced cyclonic circulations of hurricane intensity from initial conditions containing weak vortices. Other experiments aimed at simulating the global circu- lation have produced concentrated low-pressure centers within the trop- ics, but the horizontal resolution has been so coarse that it is impos- sible to say whether the models are trying to simulate hurricanes. Nevertheless, from our general knowledge of atmospheric dynamics together with the observation that hurricanes do occur and continue to occur year after year, we can safely conclude that hurricanes not only may but must occur if nature is left to its own devices. We could make a similar statement about other at- mospheric motion systems (e.g., tor- nadoes) that occur repeatedly. Such reasoning does not apply to everything that is observed in nature. It would be incorrect to conclude, for example, that a particular species of animal is necessary simply because it exists. If we should destroy all members of the species, there is no assurance that evolutionary processes would ultimately create the same species again. However, hurricanes are not a species; new hurricanes are not ordinarily born of old ones. On the contrary, they, or the weaker tropical disturbances that mark their origin, appear to be spontaneously generated when the proper distribu- tions of atmospheric temperature, moisture, wind, oceanic temperature, and probably certain other quantities occur in the tropics on a worldwide or ocean-wide scale. Strictly speaking, therefore, we should modify the statement that hurricanes are necessary by saying that they are necessary only if the larger-scale conditions characterizing the tropical environment are main- tained over the years. The absence of hurricanes in the southern Atlantic Ocean is presumably due to the local absence of favorable large-scale conditions, as is the relative scarcity of hurricanes in other oceans during the winter season. What If Hurricanes Could Be De- stroyed?— Assuming that the tropi- cal environment is favorable to the formation of hurricanes, the latter, in forming, will exert their own ef- fects on the environment. Hurricanes, by virtue of the active cumulonimbus clouds that they contain, are effective in transporting large amounts of heat and moisture upward to high levels. They may also carry significant amounts of heat, moisture, and mo- mentum from one latitude to another. In any event, they act to alter the environment; in the long run, their effect on the environment must be exactly canceled by that of other processes. Suppose, then, that nature is not allowed to take its course. Suppose 132 HURRICANES that we possessed the means, not for directly altering the large-scale con- ditions that favor the development of hurricanes, but for destroying each hurricane individually during its formative stages, soon after its initial detection. In the hurricane-free world that we would have temporarily cre- ated, the effects of hurricanes on the environment would no longer cancel the other effects and the environment would proceed toward a different state of long-term statistical equi- librium. Very likely, the new environment would be more favorable for the natural development of hurricanes than the old one. This would be true if one of the natural effects of hurri- canes is to remove from the environ- ment some of its hurricane-producing potential, as would be expected if the hurricane is an instability phe- nomenon. Perhaps a super-hurricane would then try to form to do the work of the ordinary ones that were suppressed; perhaps it would not. In any event, the task of artificially removing the hurricanes one by one, if such a task can be visualized at all, would become even more difficult than it had originally been. Beneficial Effects The most frequently cited bene- ficial effect of hurricanes is probably the rainfall that they supply to certain areas, with its obvious value to agri- culture. A familiar example of such an area is the southeastern United States, where a fair fraction of the total annual rainfall is supplied by tropical storms. Yet even if this region were deprived of all its hur- ricanes, there would still be ample rainfall left to support other crops not presently raised in this region. This leads us to suggest that the principal beneficial effect of hurri- canes may be to help preserve the climatic status quo — a status quo which the hurricanes themselves have helped to create. To appreciate the value of preserv- ing the status quo, let us suppose that two regions of the United States, each possessing a reasonably satisfactory climate, could somehow suddenly ex- change climates with one another. The climatic statistics of the United States as a whole would then be unaltered. Yet the average climate of the United States would be worse, because the climate would be "worse" in each of the two regions in question. That is, the new temperature and rainfall regime in each region would presumably be unfavorable to the plant and animal life existing there, especially to the crops, and very likely also to many aspects of human culture. The new climates would favor new flora and fauna, and after a sufficient number of years those in one region might become effec- tively interchanged with those in the other. But during the period of adjustment there would be a net loss. Since hurricanes exert a modifying influence on the larger-scale tropical environment, a further effect of hurri- canes is to help preserve the climatic status quo throughout the tropics, even in those areas not frequented by heavy hurricane rains or violent hurricane winds. Here, too, the effect may be beneficial. Geomorphological Effects of Hurricanes The morphologic changes induced by hurricanes are concentrated along seacoasts and the shores of large estuaries. As they move inland, few major tropical cyclones encounter at- mospheric conditions necessary to maintain their destructive violence for as much as 100 miles. Only rarely are they capable of retaining their structures when crossing land areas, as from the coast of the Gulf of Mexico to New England or to the Canadian border. Hurricane Camille (1969) — shown in Figure V-5 — reached the Gulf Coast as the most intense hurricane ever reported, breaking records for barometric depression and wind ve- locities and bringing tragic devasta- tion to the coast of Mississippi. It retained its identity for an exceptional distance, causing excessive rainfall and flooding that did considerable damage in West Virginia and south- western Virginia the day after leaving Mississippi. And yet, Camille caused few morphologic changes of any con- sequence. It effected many short- lived, minor physical changes on is- lands in Louisiana and Mississippi, but in comparison with losses in hu- man and animal life and with destruc- tion of property, the physical changes were trivial. Effects of Differing Coastal Characteristics Morphologic changes resulting from hurricanes depend mainly on the physical characteristics of the coasts involved. Three examples will illustrate the relationships: Plum Island, Massachusetts, expe- rienced the impact of Hurricane Carol (1954). A detailed line of levels had been surveyed across the marshes behind the island, the coastal dunes, and the island's beach. This survey was completed the day before Carol arrived. On the morning following, the beach was broadened and reduced as a result of wave erosion to a level well below that determined by the instrumental survey. Three days later, however, most of the beach had been restored, and within a few days following its profile had re- turned essentially to its pre-hurricane condition. 133 PART V — SEVERE STORMS Figure V-5 — HURRICANE CAMILLE, 1969 Hurricane Camille on August 17, 1969, in addition to being very intense, covered an extremely large area as shown in this segment of a satellite picture from the geo- stationary satellite ATS 3. A geostationary satellite is fixed relative to the earth and so is able to photograph the same area once every 25 minutes. Camille was first observed as a large area of cloudiness over the Lesser Antilles. It was tracked for over a week before it hit the Mississippi coast with 190-mph winds and 30-foot tides. Even though adequate warnings were given, many people were killed as a result of coastal flooding. Mauritius, during the southern- hemisphere summer of 1960, felt the effect of Hurricane Alix, which passed close to its west coast in January, and the full impact of Hurricane Carol in February. Carol was accom- panied by the lowest barometric de- pression and most violent winds, as well as the greatest economic loss, ever experienced in the southwestern part of the Indian Ocean. The path of Carol was such that the 1,200 square mile area of Mauritius was completely covered by the passing eye of the storm. It happened that six months earlier a field party of the Coastal Studies Institute of Louisiana State Univer- sity had completed an intensive study of the vegetation, landforms, and beaches of the entire coast. Following Carol, field parties returned in 1960 and again in 1963 to assess changes. As a great number of photographs had been taken during the first visit, an opportunity was afforded for tak- ing subsequent photographs from identical positions with the original camera. Many individual plants were re-located, and their conditions were compared on a basis of pre-hurricane, a-few-months-later, and three-years- later investigations. The photographs and other comparisons demonstrated very minor physical changes, an im- mense upset in the exotic flora, and the rapid recovery of endemic vegeta- tion. Louisiana, in June 1957, experi- enced the direct impact of Hurricane Audrey, a storm that caused the greatest loss of life and property damage of any early-summer hurri- cane on the Gulf Coast. The coastal marshes were flooded to almost rec- ord depths of as much as 13 feet. The surge of sea water removed practically all beach sand and shell for about 100 miles along the coast of western Louisiana. Loss of this thin, protective armor exposed readily eroded marsh sediments to wave ero- sion, which was responsible for ac- celerated coastal retreat for as long as four years, after which effective beaches accumulated. In 1953, a field party had been engaged in the study of a coastal mudflat that began to form in 1947. The party had implanted 25 monu- ments as reference points for that number of surveyed cross sections. Most of these survived the onslaught of Audrey and were used to monitor coastal retreat at several-month in- tervals. The most spectacular geomorphic event related to the hurricane was the lifting, shifting, and deposition of two huge masses of mudflat sediment during the storm surge. These de- posits were separated by about 19 miles. The western mass had a max- imum length of 12,350 feet; the east- ern deposit, 11,350 feet. The respec- tive widths were 1,050 and 1,000 feet. Each overlapped the shore and ex- tended inland about 2,051 feet, with an original thickness of 11 inches. Several months later, after drying, each mass had formed a sharply bounded, dense sheet of gelatinous 134 HURRICANES clay up to 6 inches thick; they are permanent additions to the marsh deposits. Some Generalizations The three specific examples given here justify several generalizations that can be substantiated by many other case histories: 1. Catastrophic as they are from human, biological, and eco- nomic standpoints, in most in- stances hurricanes result in only minor and ephemeral geo- morphic changes, and these are confined to coasts. 2. A coast where durable rock is exposed to the violence of storm attack (Mauritius ex- ample) suffers negligible physi- cal change. 3. A coast flanked by deep water close to the shore (Plum Island and Mauritius examples) is af- fected mainly by high seas. Unconsolidated materials such as beaches and sand dunes ex- perience abrupt changes, but these last for only short periods of time. 4. A coast flanked by a broad, gently inclined continental shelf, with a long fetch across shallow bottoms, suffers changes associated with flood- ing (Louisiana example). Hurricane Carol (Mauritius) brought a storm surge that registered only about 33 inches above expected level on the tide gauge at Port Louis. The island is surrounded by deep water. Hurricane winds generated high seas along all shores, however, and it was these that accounted for physical and biological changes. Much the same experience was associated with another Hurricane Carol (Plum Island). At Plum Island, the 10- fathom isobath hugs the shore closely, and a depth of 50 fathoms lies only 6 miles out. In contrast, in southern Louisiana the 10-fathom isobath lies about 43 miles from the shore, and the 50-fathom depth lies some 118 miles out. Hurricane surges are low over open ocean and are not significant aboard ship, but they rise to 15 feet or more when their rate of forward advance is reduced by shear or friction, creating greater and greater turbulence and more vigorous internal waves as they travel across wide, gently rising bottoms, especially at shallow depth. Although not much coastal change ordinarily occurs when water attains a depth of more than 5 fathoms within a short distance, too much de- pendence should not be attached to this relationship. With gently in- clined bottoms, offshore surges may grow to proportions that create ex- tensive flooding. These surges con- tinue for long distances, both across shallow bottoms and adjacent coastal lowlands. Even in the extensive and shallow area east of New Orleans, local inhabitants identify channels in the marsh and cuts across linear islands as having resulted from hur- ricanes in 1915 and 1925. A popular resort on Isle Derniere, south of New Orleans and landward about 27 miles from the 10-fathom isobath, was wiped out with tragic consequences in 1856, when the position of the low sandy spit on which it was built was shifted westward. Hurricane Protection: Problems and Possibilities An individual hurricane arrives as a possibly catastrophic event, one that is likely to be considered unique in the minds of people affected. The fact is, however, that the storm is but one of a recurring series that reach the region at highly irregular inter- vals. Hurricane arrivals are as un- certain as those of impressive earth- quakes. Although the present state of the art does not justify exact fore- casts concerning either, except for short terms in the case of hurricanes, both meteorologists and seismologists recognize that there are definite hur- ricane- and earthquake-prone regions. Eventually, it may be possible to educate people living in them to recognize that they must protect themselves against potential catas- trophes. Most hurricanes reaching the United States originate either be- tween the Azores and Cape Verde Islands or else in the Caribbean. There is no evidence that any origi- nate within 6" of the equator. In most cases they are first identified in latitudes between 10 and 20° north. The shores of the Gulf and Atlantic coasts, from Brownsville, Texas, to Lubec, Maine, are every- where vulnerable to hurricane attack. Tracks are particularly concentrated near Puerto Rico and Florida, but extreme damage has occurred around all parts of the Gulf of Mexico and up the Atlantic seaboard at least as far as Cape Cod. Defense against events such as hurricanes, tornadoes, earthquakes, and destructive volcanic activity is most effective in places where dis- aster strikes most frequently. Cy- clone cellers have undoubtedly saved many lives in the American Middle West. The Japanese have done well in designing structures that withstand intense earthquake tremors. Practically all serious damage re- sulting from hurricanes is caused by human mistakes. Protective beaches are mined for sand, shell, or gravel. Sand dunes, among nature's most effective coastal protectors, are bull- dozed away to level land for building sites or even to enhance seascape views. A trip along any part of the Atlantic coast between Florida and Cape Cod soon after a hurricane will demonstrate gross variations in dam- age, depending on whether beaches or dunes had been altered seriously. Cities and towns suffer most, not only because they are concentrations of people and buildings but also from the fact that they have introduced 135 PART V — SEVERE STORMS many more "improvements" that de- stroy or upset natural conditions. In- tervening rural areas are left rela- tively untouched, particularly if their coastal sand dunes have been left in- tact. It is difficult to convince people that hurricanes bring most disastrous results to places near disturbed beaches and sand dunes, and that substantial buildings reduce losses of life immensely. Hurricane Camille evidenced tremendous contrasts be- tween the minor damage to substan- tial buildings and the destruction of shoddy structures, however nicely adorned. Great loss of life occurred in hotels and motels with inadequate framework, the buildings being held together mainly by wallboard or in- sufficiently bonded partitions of thin concrete blocks. Surges up to twenty feet high did relatively little damage, however, to buildings with adequate frames, whether of wood or steel. Trailer courts were wiped out, even several blocks back from the shore, while old homes with good construc- tion withstood the surge much better even where they were located on or near the Gulf of Mexico. While the number of seashore buildings anchored on effective pil- ings often increases for some years after a hurricane, this is not always true. After Hurricane Audrey, nearly all new houses were built on concrete slabs at ground level, following the dictates of a current style rather than in anticipation that the buildings will probably be flooded by several feet of seawater within a decade or two. People appeared to assume that Au- drey would be the last hurricane to strike the coast of southwestern Louisiana. The National Weather Service per- forms an invaluable service in pro- viding hurricane watches, alerts, and warnings, each of which becomes progressively more specific about time of arrival and width of danger- ous impact as the storm nears the mainland coast. But to what extent has public confidence been created? For some reason the people in a small but active community on Breton Is- land (east of the Mississippi River Delta) heeded a hurricane warning in 1915. The buildings in the commu- nity were totally destroyed, and have not been rebuilt, but every inhabitant was evacuated before the storm struck, without the loss of a single life. In 1957, on the other hand, few people heeded timely, adequate warn- ings of the approach of Hurricane Audrey toward the Louisiana coast. Many hurricanes had brought storm surges to the area, but all had been lower than the elevation of the higher land in the vicinity (about 10 feet). Hurricanes were an old story. Most of the people remained at home and were totally unprepared for vigorous surges that swept as much as three feet across the highest land in the vicinity, causing tremendous loss of life and property. On several occa- sions during the past thirteen years people have evacuated the region as soon as early warnings have been issued, but in no case did a dangerous surge occur. Will these experiences result in destroying confidence in warnings by the time that the next potential disaster appears? Awareness of danger is almost im- possible to maintain for disasters that recur a generation or more apart. Probably the most effective hurri- cane-protection measures result from legal actions, at state and local levels, such as the formulation and enforce- ment of adequate building codes, pro- vision for rapid evacuation, mainte- nance of reserve supplies of fresh water for domestic use, well-con- structed sanitary systems, and the availability of carefully planned health and emergency facilities. Needed Scientific Activity In their pristine condition, factors associated with the destructive effects of hurricanes are in reasonable equi- librium with those that resist geo- morphic change. Scientific knowledge about hurricane origins, mechanics, physics, and behavior slowly in- creases, as does knowledge concern- ing the destruction or alteration of shoreline landforms and the accumu- lation and transport of near shore sediment. The effects of upsetting natural environmental conditions may be forecast with considerable qualita- tive precision. In order to understand more com- pletely the relations between hurri- canes and their physical effects on coastal lands, the following suggested activities appear to be pertinent: 1. Accelerating the Weather Serv- ice's program of hurricane tracking and its ability to fore- cast the intensity and time of arrival of individual storms and to designate the coastal areas most likely to suffer. 2. Encouragement of studies by coastal morphologists to iden- tify areas where physical changes are imminent, with em- phasis on man-induced causes, in the hope that they may be- come expert in assessing the results of undesirable practices. 3. Creation, on a national level, of a group charged with moni- toring proposed activities of U.S. Army and other coastal engineers from the standpoint of assessing probable long-term changes that designs of de- fenses against the sea are likely to induce. This should be a cooperative, rather than strictly policing, activity. There is tre- mendous need for better com- munication between scientists and engineers. Scientists need to be better informed about en- gineering design practices, and engineers need better under- standing of the conclusions of basic scientific research. 136 2. TORNADOES Status of Tornado Research Tornadoes are among the smallest in horizontal extent of the atmos- phere's whirling winds, but they are the most locally destructive. Al- though they are occasionally reported from many places, it is only in the United States that very intense tor- nadoes occur frequently. A typical intense tornado accompanies an otherwise severe thunderstorm, lasts about 20 minutes, and damages an area a quarter of a mile wide along a 10-mile path toward the northeast. The maximum winds (never accu- rately measured) are probably be- tween 175 and 250 miles per hour, but damage is caused as much by a sudden drop of pressure, amounting in extreme cases to about 0.1 of the total atmospheric pressure, or 200 pounds per square foot. Especially when structures are poorly vented, roofs and walls are moved outward by the higher pressure within; then, as their moorings are weakened, they are carried off horizontally by the wind. During the past 15 years, about 125 persons have been killed an- nually by tornadoes. Average prop- erty damage has been about $75 million. These figures may be com- pared with estimated losses owing to lightning, hail, and hurricanes as shown in Figure V-6. The high tornado death rate in relation to property loss is attribut- able partly to our inability to warn effectively against impending torna- does. A tornado is a very destructive phenomenon, but it usually exists for only a short time and affects only the thousandth part of a region cov- ered by tornado-spawning thunder- storms. Extreme variability is an essential characteristic. Most tornado losses are associated with just a few storms that utterly destroy the struc- tures in significant portions of urban areas or in whole small communities. These events, sudden and never fore- shadowed more than a few hours in advance, leave the survivors stunned amid desolation; they call for a sud- den focused response, of a magnitude akin to that demanded in war, by the affected community and by state and national governments. Tornado Prediction We have noted that the typical tornado accompanies an otherwise severe thunderstorm. Severe thunder- storms are themselves hazards and demand public forecasts, and the possibility of tornadoes is usually indicated when severe thunderstorms are predicted. Our forecasts, which must start from a description of the present state of the atmosphere, are less specific than we would like. This lack of specificity is associated in part with a lack of knowledge, but also with observations that are too sparse to de- scribe atmospheric variability on the scale of tornado or thunderstorm phe- nomena. Thus, the extent of a severe thunderstorm is 10 to 20 miles and the lifetime of a storm system is generally about six hours. But the distance between first-line surface weather stations is about 100 miles, and between upper air stations about 150 miles. Observations are made hourly at the surface stations (more often under special conditions) but usually at only 12-hour intervals at the upper air stations. Therefore, even if our knowledge were otherwise adequate to the task, the observing system would limit us to indicating the probability of thunderstorms in regions much larger than the storms themselves. At present, tornadoes are fore- shadowed from one to six hours in advance, for periods of about six hours and in regions of about 25,000 square miles. About 50 percent of such predictions are correct, with the Figure V-6 — COMPARATIVE LOSSES DUE TO SEVERE STORMS AND HURRICANES Average Annual Ave rage Annual Property Type of Storm Deaths in U.S.* Damage in U.S.* Tornado 125 $ 75 million Lightning 150 100 million Hail — 150 million Hurricane 75 500 million *Based on data from 1955-1970 Loss of life is almost four times greater from severe storms than from hurricanes, while property damage is less than one-half as great. 137 PART V — SEVERE STORMS incorrect forecasts being nearly di- vided between cases without tor- nadoes and cases with tornadoes outside, but near, the predicted re- gions. It should be noted that the climatological expectancy of torna- does during six hours in a randomly selected 25,000-square mile area in eastern and central United States is only about one in 400. Plainly, then, present forecasts give evidence of considerable skill in identifying the meteorological parameters associated with severe storms and tornadoes and in correctly anticipating their development. Briefly stated, the storm-forecast- ing parameters are warmth and mois- ture in a layer about 5,000 feet deep near the earth's surface, with a cool dry region at intermediate levels, strong winds in the upper atmos- phere, and a trend toward intensifi- cation rather than diminution of these conditions. The prediction of all the necessary features is based on ob- jective techniques, rooted in statistical and dynamical evaluations and modi- fied by the judgment of experienced forecasters. Forecasts of severe storms and tor- nadoes one to six hours in advance are considered "watches." In view of the wide area covered by the forecast relative to the area likely to be affected, the public is encouraged by a "watch" merely to remain alert to further advisories. The forecasts are disseminated by teletype from the National Severe Storm Forecast Center in Kansas City, Missouri, to local offices around the country. Oc- casionally, a local National Weather Service office may issue a modified local forecast which takes special account of peculiar local conditions. Since subscribers to the teletype service include most elements of the communications media, storm indi- cations are quickly brought to the attention of the radio and TV public. Tornado Warning Severe storms are observed as they develop by Weather Service offices, local government authorities, and private persons. When the Weather Service, through its own action or a report by a private observer, becomes aware that a severe storm or tornado exists, a warning to communities in the extrapolated path of the storm is issued by teletype, or immediately by radio and television if the situation warrants. The public in the threat- ened communities may be warned by various actions of local authorities, including the sounding of sirens. The few minutes' warning thus provided is credited with a twofold reduction in loss of life. The greatest loss of life from a tornado is often to be found in the first community visited by a storm, downstream locations having the benefit of longer warning time. These days, observer reports are valuably augmented by radar ob- servations. The primary radar net- work of the National Weather Service has stations spaced 200 to 250 miles apart. When severe storms threaten, the radar screens are monitored con- tinuously. The more intense echoes are associated with heavier precipita- tion and a greater likelihood of hail, strong straight-line winds, and tor- nadoes. Severe tornadoes are often associated with a hook-shaped ap- pendage on the echo. Thus, the forecaster's observation of the intense radar echoes provides a continual check on visual sightings and damage reports, and provides for timely warnings to communities lying in the projected path of a storm. Tornado Research Observations — Accurate descrip- tion of tornado vortices and of the atmospheric conditions preceding and accompanying tornadoes is essential for improved understanding and pre- diction of tornadoes, and for the possible development of practical means for influencing tornadoes ben- eficially. But scientific observation of tornadoes is made difficult because of their random occurrence, brief duration, small size, and great vi- olence. In an attempt to study tornado vortices directly, the National Severe Storms Laboratory has maintained a network of 30 to 60 conventionally equipped surface stations during the past seven spring seasons in an area where tornadoes are relatively fre- quent. Only two of the stations, however, have been directly affected by the winds of a tornado vortex during this period. The network den- sity would have to be increased by a factor of 100 to obtain detailed data on the wind distribution in tor- nado vortices. For detailed informa- tion on the vortices, therefore, we are forced to rely on chance observa- tions, engineering analysis of dam- aged areas, eyewitness accounts, and on the results of efforts to obtain data remotely by photography and by indirect probes such as radar. Our information indicates that the tornado is characterized by an inner region where the winds decrease to- ward the center, as in solid rotation, and an outer region where the winds fall off with increasing distance. Many other tornado features are highly variable. The tornado cloud, presumed to be the surface of con- stant reduced pressure at which the well-mixed subcloud air is cooled to saturation, varies in size and shape. In some photographs it appears as un- commonly smooth, suggesting lami- nar flow, in others as highly irregular, suggesting strong turbulence. Such differences are quite important from the point of view of tornado dynam- ics. Since the less fierce waterspouts are usually cylindrical and smooth- walled, we are led to search for sig- nificant variability in surface rough- ness or atmospheric conditions over land to account from the apparent variability of turbulence and shape of tornadoes. The electrical properties of the tor- nadoes also appear highly variable. Finley's report on 600 tornadoes, pub- lished in 1882, lists the observation of thunder and lightning in 425 asso- 138 TORNADOES ciated rainstorms. In 17 cases, lumi- nosity of an apparently electrical origin was noted in the tornado fun- nel itself, while in 49 cases the ab- sence of any electrical indication in the cloud was specifically reported. More recently, interest in electrical theories was stimulated when Jones reported unusual 100-kHz radiation from a tornadic storm. Vonnegut presented an electrical theory of tor- nadoes; Brook has reported on the magnetic anomaly observed during touchdown of a tornado near Tulsa; and Weller and Waite have proposed that tornadoes are associated with intense electromagnetic radiation at television frequencies. On the other hand, Gunn measured the electrical activity of the tornadic storm that devastated Udall, Kansas, on May 25, 1955, and found it to be "more or less typical of exceptionally active storms." Rossow has measured mag- netic fields over numerous water- spouts and found little disturbance. Kinzer and Morgan located the posi- tion of sferics sources in the tornadic storm in Oklahoma on June 10, 1967, and reported no obvious connection between areas of cloud lightning and tornado locations. In a sense, the tornado itself is only an important detail of the circulation and energy balance of the larger thunderstorm. By virtue of its larger size and greater frequency, the typical parent thunderstorm lends itself much more to detailed examination. There- fore, present research is concentrated on identifying details in atmospheric structure associated with formation of tornadic and non-tornadic storms, with the variable behavior of different storms that form in the same general area, and with the evaluation of the way forces manifested in the storm environment combine to produce ma- jor features of the in-storm motions. To this end, experimental networks of closely spaced surface and upper air stations are used along with quan- titative radar and specially instru- mented aircraft. We have learned that severe and enduring tornadoes form near the small low-pressure areas associated with the hook-shaped radar echo marked by the arrow in Figure V-7. Within the last decade the combina- tion of observations and data gath- ered by many sensors at one place has taught a great deal about major features of thunderstorm circulation and, indeed, has revealed important but hitherto unidentified distinct storm classes. Mathematical Modeling — All present-day mathematical models of weather represent extreme simplifica- tions of the natural phenomena. We are still especially far from simulat- ing realistically and in combination the many factors associated with the development of local storms. Most adequate for their purpose are the models of atmospheric be- havior on the scale oi culation and large weathe In use at the National Mcteoro Center in Washington, D. C, such models predict the general patterns of horizontal wind, moisture, and vertical currents; they provide useful guidance to the thunderstorm fore- caster, who combines their indications with his knowledge of the distribu- tion of features specifically associated with local storms — and with his judgment — to forecast the probable location of storms. Models that fore- cast directly the parameters known to be important to thunderstorm de- velopment are just beginning to come into operational use. Some incorpo- rate both dynamical and statistical methodology and provide somewhat more detailed spatial distributions over the United States than has been available heretofore. Figure V-7 — RADAR VIEW OF A HOOKED ECHO The picture is of a Plan Position Indicator (PPI) presentation of a severe storm over Oklahoma City on May 26, 1963. Range marks denote intervals of 20 nautical miles. North is toward the top. The radar is located at the center of the range circles. The arrow points out the location of the tornado. 139 PART V — SEVERE STORMS Local convective phenomena are significantly affected by a greater variety of processes and factors than widespread weather, and are corre- spondingly more difficult to model realistically. To date, we have some two-dimensional models that incor- porate simplified formulations of pre- cipitation-related processes and of entrainment. These show some skill in predicting, for example, the maxi- mum height to which a cloud tower rises with specified ambient condi- tions. The most comprehensive of today's models, however, is probably less detailed by a factor of at least 100 than one that would illustrate significant features of the asymmetric horizontal and vertical structure. Today's mathematical models of the tornado itself treat cylindrically symmetric cases. At the edge of knowledge, we find steady-state mod- els such as Kuo's, which appears to describe essential features of observed tornadoes in terms of an unstable vertical stratification and an ambient field of rotation. The fact that these features are often present when tor- nadoes are absent, however, serves to emphasize that we still have very far to go in our modeling and observing to identify the factors responsible for concentrating angular momentum in the developing tornado. Experiments — The control of pa- rameters afforded by laboratory con- ditions recommends the experimental approach to identification and analy- sis of factors responsible for the growth of tornadoes. Such experi- ments have been conducted for many years, often in conjunction with theo- retical investigations, and realistic- appearing vortices have been pro- duced in various liquids and in air under a considerable variety of ex- perimental conditions. The very ease with which tornado-like vortices can be produced experimentally has made it difficult to progress much beyond theoretical implications regarding the development of swirling motion in converging fluid at the base of a ris- ing column, and the important influ- ence of boundaries. Concurrent with the recent devel- opment of numerical analysis of large-scale atmospheric circulations, however, has come appreciation of the importance of similarity both in theoretical and experimental model- ing. Similarity in flows on different scales is said to exist when the ratios of various quantities involving inertia, viscosity, rotation, and diffusion are the same. Considerations of similar- ity, and increased attention to such natural observations as are available, are leading to design of models more revealing of the effects of natural conditions. Thus, Turner and Lilly have con- structed physical models of vortices driven from above to simulate the convection in a cloud, and have found rising motion in the vortex core with descending motion in a surrounding annulus. Ward, noting that no tor- nado vortex can be indefinitely long, has ingeniously separated a fan from the vortex it creates in controlled in- flow beneath. In this model, his con- trol of the inflow angle and depth of the inflow layer represent the most important influences in the creation of a vortex, its intensity and diameter, and, in contrast to earlier models, the development of a central downdraft. The problems of developing theo- retical and experimental models in- dicate the importance of observations on even gross characteristics of tor- nado circulations. Is the flow upward or downward in the funnel core? How is tornado behavior, such as funnel-skipping, related to the rough- ness of underlying terrain? What is the wind inflow angle and air pres- sure at various distances from the visual funnel? How does the wind vary with height in the vicinity of tornadoes? If we could better answer these questions for atmospheric cases, we could design experiments accord- ingly, and rationally extend our search for influential parameters of the flow. Comments on Investigational Techniques We have surveyed observational, theoretical, and experimental aspects of tornado investigations. The vari- ety and complexity of processes im- plicit in tornado development and maintenance, and the rarity, relatively small scale, and intensity of the natu- ral phenomena have been sources of great difficulty. Let us briefly con- sider the helpful technological ad- vances that may reasonably be antici- pated and whose development should be encouraged. Emerging Observational Tech- niques — With regard to observa- tions, no available prototype tech- nique seems practical for measuring details of the distribution of velocity and other parameters in a tornado vortex. With the encouragement of severe-storm study programs, how- ever, greater numbers of observations — including useful motion pictures — should become available, and we may reasonably expect an opportunity in the next few years to extend the im- portant study of the Dallas tornado of April 2, 1957, made by Hoecker and his colleagues. Emphasis should be placed on ob- serving the circulations around severe storms, since it is certain that the intensity of a storm and the occur- rence of tornadoes is greatly con- trolled by the storm environment. In addition to encouraging existing pro- grams having this objective, we may put special emphasis on two emerg- ing tools. One is meteorological doppler radar, which in units of two or three can map the distribution of precipitation velocity with unprece- dented detail. The development of an improved doppler capability would have value both for fundamental re- search and for research on an im- proved warning system, the latter by providing bases for evaluating the distinguishing features in a storm velocity field characteristic of an im- pending tornado. Doppler capabil- ity for clearer tornado identification 140 \DOES needs to be assessed. Although some meteorological doppler radars are presently in use and other systems are under development, the pace of work seems slow. The second emerging technique is satellite infrared spectrometry, which is providing new detail on the vertical thermal stratification of the atmos- phere at intervals of about 30 miles. Further development of the satellite system should result in better analy- sis of severe thunderstorm precursor conditions over the United States and refinement of our forecasting ability. Computers — With regard to mathematical modeling, greater real- ism will be possible as computers become larger and faster and as theo- retical models are revised in light of observations and experimental re- sults. Of course, many techni-socio- logical forces are already encouraging the development of improved com- puters. We may emphasize here that no conceivable computer can ever solve meteorological problems in such a way that careful scientists will not be an essential part of problem preparation; indeed, theoretical in- terpretation of data from observa- tional and experimental programs will be increasingly required to de- velop reasonably posed mathematical formulations. Physical Models — With regard to physical modeling of thunderstorms and tornadoes, the difficulties inher- ent in modeling significant atmos- pheric processes such as condensa- tion and precipitation, in diminishing the effect of container sidewalls to levels consistent with the atmos- phere's lack of sidewalls, and in simulating the vertical density gra- dient and diffusion processes charac- teristic of the atmosphere will con- tinue to represent serious obstacles. These problems have been less seri- ous with respect to interpretation of the more essentially two-dimensional flows representative of atmospheric circulations on larger scales. Never- theless, experimental methods should continue to be important for testing tornado hypotheses and suggesting new lines for observational and theo- retical study. The General Status of the Operational System for Severe Storm Prediction and Warning Present-day severe-storm forecasts are immensely valuable, but we wish they were more precise and more ac- curate. Although numerical methods have been used for forecasting large- scale weather patterns for over ten years, the development of mathemati- cal models relevant to the smaller scale of local storm complexes is still in its infancy. Basic improvements in the quality of severe-storm fore- casts depend on the development of new understanding of storm struc- ture and dynamics, the interaction between severe local storms, and the larger patterns of air motion that establish the general conditions favorable for storm development. As previously indicated, such improved understanding can be expected to evolve only as the insights provided by more detailed observations are assessed by careful scientists with the aid of more powerful computers. Eventually, methods will be devel- oped combining such detailed data as that provided by radar and satellites with other weather parameters in dynamical storm models; appropriate ways to use such detail in operational forecast preparation should then be- come clear. At present, we can strive to hasten the preparation and distribution of such forecasts as we have. To this end, hand analysis of patterns signifi- cant to local storm development is being significantly replaced by com- puter techniques. The radar network, which is the backbone of the system used for severe-storm warning, also lends itself to significantly advanced automation. Displays like that shown in Figure V-7 can be replaced by contour-mapped echo representa- tions. (See Figure V-8) A correspond- ing digital array can be pro< simultaneously (see Figure V 9) as a basis for automatic preparation and dissemination of extrapolation fore- casts. In midwestern United States, the Weather Service is presently starting to develop an operational test of advanced radar systems in order to evaluate the probable costs and benefits of various system de- signs for nationwide application. Prospects for a Measure of Tornado Control The energy production involved in one severe local storm is comparable to the total power-generating capacity of the United States. Thus, the control of severe-storm phenomena clearly requires an ability to direct far greater amounts of energy than those locally applied by man at pres- ent. This will depend on developing knowledge of how to modify the processes by which nature's supply is utilized. For example, silver iodide and a few other chemicals are used to stimulate the freezing of water drops that otherwise remain liquid during cooling to temperatures somewhat below their melting point; the arti- ficial release of the latent heat of fusion thus achieved can raise the air temperature enough to enhance sig- nificantly the growth of some clouds and to hasten the dissipation of others. Conceivably, this kind of process could be applied to alter na- ture's choice for rapid growth among a host of nearly identical clouds. Other means for modifying torna- does might involve alteration of the earth's topography and roughness to decrease the probability of tornadoes over inhabited areas, and the direct application of heat at a point in time and place where such application would beneficially modify the course of subsequent events. It must be plain from the foregoing discussion, however, that we are still very far from having a reasonable basis even for estimating the likelihood that such efforts could ever be successful. 141 PART V — SEVERE STORMS Figure V-8 — CONTOUR-MAPPED PPI DISPLAY The figure shows the PPI-scope of the 10-centimeter WSR-57 radar at the National Severe Storms Laboratory in Norman, Oklahoma on April 26, 1968. Differences in shading indicate intervals of a factor of 10 in received echo power. From such an electronic display it is possible to determine the most dense part of a storm. Range marks are at intervals of 20 nautical miles. North is at the top of the figure. 142 ADOES Figure V-9 — CONTOUR-MAPPED DIGITAL DISPLAY Imp saasa* .zzii« _ 999983 22222 996872 998996 250 9879971 _iW 8679982 2 34 2S6 97799731 979999421 11 1133432122222 ■1??3344A32222 122 .1123*5543221222 - - 12356465321 1234556666532 — 122J34S47Z644556J2 1234466777654444322 2234 6r666t.5S4133 332 258 -260 262 264 96b99942 -92989462- 9B877742 9a66B973 26o lb* 9bB8998622 97789976 33 270 272 274 -2X»- 9669998644 8e678B8765 97678877 75 9777B8 7773 278 -28J- 9777778B73 9777779862 9767777763 9997787552 967777o6 32 956677»621 233466665554443221 23446776555444332 2 344556 77 7665413332 22 -22455544774455*33222222— ■.3566 466665 5443322221 12 345c 66 77644433 2121 123345566553333322 22 3444455554333222^ 12223444566654322221 1222333 445554432,21V 11 11 12222333455554322 — U4A 122222333*5543221- ^4^ 26o 2B8 290 9577776622 -2A2 957677B721 122 11222223455543221 1221111122222 345*43221 11122234443221 2222443322 U 221 122345532221 .32 23 34 5'i 22 i — 294 -29»- 298 3w0 302 2-04 94577665 9447777..21 222 9776984222333321 905544455664222 97'i44ii>S5>»443 — 310 -312- 99455466 5556641 99-554487347643 99455554 335541 99476765435538 — 99676663234422 997774.H3-.33l 318 320 J22 324 J26 999843442233 609954*4 3555 996754543333 990655>54442 99876555 5532 99987*6664 330 999855f763 221 -3»2 0986766762 222J-. 134 9989977752 2222. -43* 99909765 53 r- 22 — H- 22 i. 22 22 3443 21 -222 344424 12224542 2-25552 — 2 2465 3 2 34J5 42 111 2 3455552 - 24464653 22345666211 W345555443222 11 — I- 2234555555E4322 -234*4* 55**543 32 22 22233444*544433221 2333333333444432221 2233344 44 3334*3 2222 -222233-433332 34 3221 338 9999976322 22 -449 9<999853 22 1. 342 344 9998»873 j»9J»99*94 999999851 2222 2223334333323321 — 223344*43333333«.a21 2344433332333322221 123 555555 555*32222211 122333455543322222211 .2222344*3233322222-1, 222 222i2333333333222. -.-2-1-1233333322 32222 2^2 33443322 222 21 21111222222 12 11 11 22222222 2221 3*6 OOOOBOOO, 2763 350 9999986852 432 352 9999987h652 22 22 354 99999997642222 2*4 -356 99977998421 1*4 358 99967998 32 21 996677752 99556985 22 a 9958998722 122 — 8 ~»9»999762 10 99699753 -12 999877661121 2222 3333344332221 12 i2 2 3 33 22 2 1 1222 12221 22-2-2+ -2-222222211 12-24- 222222222221 1223333322222222 112222222211 12211 14 11221 111. -11222221 221111 14 -L6- 999865^5 1222 9999,it»*2332 18 -088 999933j3233 111 2222 -221 222 2222221 .22221^12222122 .12222222 11 222i221 . 22 1222 1222222222222221 . 2222222222222233313222223222 - -^. -22221- 1122*22223222222221 221 . 222 11 ■.22222231322 11222 112233333 332 33 J* 1222222333333222 .22464*322i 11222 22222322222^2222222222 ^2222i222A2233 32 33222-221 .1222232222212t22222 11 2111222222 2221 The figure shows a digital version of the data shown in Figure V-8. The successive horizontal lines represent 2° steps of azimuth. These are noted in the leftmost column. The vertical lines represent 20-nautical-mile intervals, the dots at the top and bottom of the diagram represent one-nautical-mile intervals. Successive digits on the map represent factors of seven in the echo intensity. 143 TART V — SEVERE STORMS Tornadoes — Their Forecasting and Potential Modification A tornado, also called cyclone or twister, is defined as a violently rotat- ing column of air, pendant from a cumulonimbus cloud, and nearly al- ways observable as a funnel. The shape of a funnel varies from a cone to a rope; its lower end does not always touch the ground. A con- firmed small tornado could be char- acterized by a damage area of 10,000 square feet, while the swath of a giant tornado covers more than 30 square miles. Thus, a giant tornado could be 50,000 times larger than a tiny one in terms of potential damage area. The annual tornado frequency changed from a minimum of 64 in 1919 to a maximum of 912 in 1967, which represents a ratio of 1:14. This does not mean that tornado frequency increased by at least one order of magnitude. Instead, reporting effi- ciency — related to the reporting sys- tem, urban development, population density, and such — probably in- creased the apparent tornado fre- quency. It is preferable, therefore, to evaluate the potential danger of tor- nadoes according to damage areas rather than their number of occur- rences. Damaging Tornadoes When a tornado warning is issued, the general public will be looking for the nearest storm shelter for protec- tion of life. Statistics show, however, that 50 percent of the total tornado damage area is produced by only 4 percent of the tornadoes. This means that half of the potential damage area can be warned efficiently if the top 4 percent of tornadoes are pre- dicted with great accuracy. If the top 10 percent of tornadoes can be pre- dicted, their damage area would cover 75 percent of the total damage area. Although these statistics do not sug- gest that only large tornadoes should be predicted to the neglect of others, accurate prediction of large tornadoes would be of great value to local residents. Small Tornadoes — The origin of large, long-lasting tornadoes seems to be quite different from that of the tornadoes at the small end of the size spectrum. Small tornadoes and water- spouts are so similar in dimension and appearance that the former can be regarded as waterspouts traveling over land. These small storms, al- though they make up a large number of all storms, are very difficult to predict. They may form within a local shear line associated with growing cumulus clouds that may or may not become thunderstorms. Small torna- does last only a few minutes, leaving a damage swath of only a few miles. Hook-Echo Tornadoes — Large tor- nadoes frequently last 30 to 60 min- utes. Furthermore, in many cases several tornadoes of similar size and intensity appear one after another, thus forming a family of large torna- does. When radar pictures of proper gain and of low elevation angles are examined, almost all tornadoes in such a family are related to a thunder- storm echo with rotational character- istics— i.e., a rotating thunderstorm is a spawning place for one to several large tornadoes. When the view is unobstructed, a rotating thunderstorm can be photo- graphed at large distances as a bell- shaped cloud with an over-all diame- ter of 5 to 25 miles. The same cloud would appear in a plan-position- indicator (PPI) radarscope as a "hook echo," with an eye at the rotation center and several echo bands spiral- ing around the eye-wall circulation. Despite the fact that a family of tornadoes comes from a rotating thunderstorm, not every rotating thunderstorm or hook echo spawns a tornado during its lifetime. It is likely that only a maximum of 50 percent of hook echoes spawn tornadoes — usually large ones. Hook-echo torna- does are responsible for more than half of the damage areas caused by all tornadoes. Detecting Large Tornadoes — The above evidence leads to the conclu- sion that large tornadoes spawn from mesoscale vortex fields identified as rotating thunderstorms, hook echoes, or tornado cyclones. The outermost diameter of such a vortex ranges be- tween 5 to 25 miles. The eye, sur- rounded partially or totally by a hook- shaped echo, rotates at the rate of 20 to 40 miles per hour at its outside edge and is 1 to 3 miles in diameter. The central pressure of a tornado- bearing mesoscale vortex or tornado cyclone is only 2 or 4 millibars lower than its far environment. An imprac- tically large and expensive network of barograph stations would be re- quired for detecting tornado cyclones. Unless a doppler radar network be- comes available in the future, PPI- scope pictures in iso-echo pres- entation with better than one-mile resolution will provide the only means of detecting tornado cyclones within some 10 minutes after their formation. Early detection of tornado cyclones is the key to a warning within a narrow zone in which there is a chance of tornado formation. Such an alley is only 5 miles wide and 50 miles long on the average, while a tornado watch area extends 50 x 100 miles, some 20 times larger than one alley area. Maximum Tornado Windspeed Windspeed is an important pa- rameter, necessary for the design of tornado protective structures. When settlers first experienced the impact of tornadoes in the Midwest, they estimated maximum windspeed to 144 be in excess of 500 miles per hour. Some even estimated a supersonic speed. Damage investigation since then has reduced general vvindspeed esti- mates to between 300 and 500 miles per hour. If these maximum-speed estimates are accurate, they would, where combined with the storm's pressure reduction, make it impossi- ble to construct tornado-proof struc- tures at reasonable cost. Fujita's study of tornadoes during the past ten years, however, has now led to the conclusion that the maxi- mum windspeed of tornadoes is much less than previously thought. Maxi- mum rotational windspeeds, as esti- mated from scaling motion pictures and characteristic ground marks, are about 200 miles per hour. The trans- lational motion of the storm must be added to the right side and sub- tracted from the left side of the rotat- ing core. If a tornado travels at its average speed of 40 miles per hour, the maximum combined speed above the frictional layer would be 240 miles per hour. Some tornadoes, such as the ones on Palm Sunday, 1965, traveled eastward at 62.5 miles per hour. For these storms, the maximum combined windspeed would be 260 miles per hour. Inside the boundary layer, the gust speed must be added to the mean flow speed, which de- creases toward the ground. Under the safe assumption that the peak gust speed could overpass the de- crease in the flowspeed toward the ground, a maximum gust speed of 300 miles per hour seems to be quite reasonable. Thus, one has: Maximum rotational speed. . . .200 mph Maximum traveling speed 70 mph Maximum gust speed 300 mph It should be noted that the higher estimated speeds were obtained by assuming the cycloidal ground marks were produced by one rotating object. Fujita's study has indicated that there are 3 to 5 spots which produce cy- cloidal marks. Thus, the speed for any one tornado of a family must be reduced bv one-third to one-fifth. Minimum Pressure Inside Tornadoes As in the case of tornado wind- speed, in earlier days pressure reduc- tion at the center of tornadoes had been overestimated to be a near vacuum or 2,000 pounds per square foot. Since then, meteorologists have tended to agree that the pressure re- duction at the storm center is between 200 and 400 millibars. It should be noted that a building will suffer also from differential pres- sure from its form resistance. A 300 miles per hour wind will produce a positive stagnation pressure of about 90 millibars at its windward side. Over the roof, however, the pressure may be negative, with the result that the roof is lifted. (The lifting force cannot be estimated unless the com- plete shape of the building is given and a wind-tunnel test is performed.) Potential Tornado Protection and Modification As a result of more recent wind- speed and pressure estimates, criteria for designing tornado-resistant struc- tures have now become feasible. Such structures could be expensive, al- though future designs and improved material could reduce costs to a level where at least public buildings in a tornado alley could be built to with- stand tornado wind and pressure. Tornadoes vary in both shape and size. The most commonly observed four shapes are: Cone shape: Large tornadoes drop down in the shape of a cone; as the storm develops, the tip of the cone reaches the ground. Column shape: A tornado or a large waterspout takes the shape of a large trunk. Chopstick shape: Thi shape of weak tornadoes and waterspouts with small diame- ters. Rope shape: When tornadoes be- come very weak, they change into a rope which often extends miles in a semi-horizontal direc- tion. Although tornadoes have such different shapes, all tornadoes and waterspouts are characterized by a core circulation surrounded by a cir- cle of maximum wind. Outside this circle, the tangential windspeed de- creases in inverse proportion to the distance from the circulation center. Chopstick- or rope-shaped tunnels may be considered axially symmetric. When the core diameter increases, as in the case of the cone and trunk shapes, there are several spots of strong suction around the edge of the core; thus, they are no longer axially symmetric. These spots of strong suction rotate around the funnel at the speed of the funnel rotation. Three ways of modifying tornado windspeed may be considered. They are: (a) a reduction of the circulation energy; (b) an increase in the core diameter without changing the circu- lation intensity; and (c) reduction of the windspeed near the ground. Reducing the Circulation Energy — This possibility depends on the counteracting energy that can be cre- ated artificially. The total kinetic energy of a tornado is on the order of 107 kilocalories, which is just about 1/1,000 of a small, 20-kiloton atomic bomb. The energy of even the largest of tornadoes is comparable only to 1/100 of the energy in a small atomic bomb. Atomic bombs obviously can- not be used to modify a tornado. We might however, investigate such power sources as an artificial jet in order to learn more about how the relatively small and concentrated en- ergy of a tornado might somehow be dispersed. 145 PART V — SEVERE STORMS Increasing the Core Diameter — This definitely reduces the maximum tornado windspeed that occurs just outside the core. Modification of hur- ricanes through eye-wall seeding is based on the similar principle in which the release of latent heat around the eye wall will literally ex- pand the eye diameter, thus reducing the extreme pressure gradient around the eye. In the case of tornadoes, it might be possible to cool the lowest portion of the core circulation. If we inject water droplets into the core at a certain level between the ground and the cloud base, they will evapo- rate as they slowly centrifuge out, thus cooling the core to increase the descending motion inside the core. The lower portion of the core will then expand, reducing the maximum windspeed. Contrary to older reports, a tor- nado cannot suck up a body of water beneath its core. Investigation of ground marks has revealed that the suction power of a tornado is weaker than a suction head of a household vacuum cleaner placed closed to the surface. It is, therefore, necessary to deliver a large amount of water in drop form into the core. Reducing Windspeed Near the Ground — This could be achieved by constructing a number of deflectors to the west and southwest of an im- portant structure such as an atomic power plant. The deflectors should be oriented in such manner that they change the southeast winds on the advancing side of a tornado to a northeast wind or possibly to a north- northeast wind, thus creating a flow converging toward the tornado cen- ter. The net effect of the convergence will be to reduce the speed near the surface. Design of deflectors should be made through aerodynamic calcu- lations and a wind-tunnel test. Other Activity Methods of estimating tornado windspeed should be explored and tested whenever feasible. Direct measurement is desirable if "maxi- mum wind indicators" are to be de- signed to stand against tornado wind. Measurement of object motion inside the tornado does not always give the air motion. Especially when an explo- sion of a structure is involved, the initial object velocity is likely to be overestimated. The designing of a low-priced "minimum-pressure indi- cator" for placement over the area of expected tornado paths is also recom- mended. Basic research on tornado modifi- cation also needs to be carried on through various model experiments and theoretical studies. Furthermore, although the probability of tornadoes is small, some important structures must be protected against severe destruction. Tornado Forecasting and Warning Tornado frequency within the United States varies from 600 to 900 per year, with the major concentra- tion through the Central Plains. Ninety percent of all tornadoes have a path-length between 0.5 and 50 miles and path-width between 40 and 800 yards. The median tornado has a path-length of 5 miles with a path- width of 200 yards. The median destructive period is less than 30 minutes. Less is known about tor- nado velocity profiles, but one can estimate that 90 percent of the peak speeds are between 100 and 225 miles per hour, with a median peak velocity of 150 miles per hour. Unfortu- nately, the upper limit appears to be around 300 miles per hour. Thus, the problem is to forecast the occurrence of a rare meteorologi- cal event which has median dimen- sions of one square mile over a 30-minute period, and to forecast it sufficiently far in advance to allow effective use of forecasts by all in- terested parties. There should be suitable differentiation for tornado classes based on width, length, and peak velocity. None of the above is possible at this time for areas of less than several thousand square miles and for more than one hour in advance. Matters Contributing to the Forecast Problem Data Network — The average dis- tance between full-time surface re- porting stations is 100 miles. Reports are made every hour, oftener when special criteria are met. Unless the special report is taken and trans- mitted near a free time-period in the teletype schedule, it is quite probable that the report will be delayed 10 minutes in reaching the user. Thus, the spacing and frequency of reports taken with the standard data network is not adequate to fully describe the severe weather events taking place within the confines of the data net- work. The average distance between upper air stations is 150 miles — and slightly more than that in the areas of high tornado incidence. Rawin- sonde releases are scheduled only every 12, and on occasion every 6, hours. But the 1200 Greenwich Mean Time (GMT) release is made in the Midwest at 6 a.m. Central Standard Time (CST), a minimum thunder- storm period, while the midnight GMT release is made at 6 p.m. CST, a maximum thunderstorm period. Ef- fectively, this produces only one use- ful report per day per station. These reports are not adequate to fully de- scribe the temperature, moisture, and wind patterns within the tropo- 146 ,DOF.S sphere. This is due partly to their spacing and frequency and partly to errors inherent in the equipment. In addition, there are data voids in the areas surrounding the United States, such as the Gulf of Mexico, the Atlantic waters adjacent to the east coast, and portions of Mexico and Canada. All of these contribute to serious lateral boundary prob- lems, the most pressing being the Gulf of Mexico. Texas, Louisiana, Mississippi, Alabama, Florida, and Georgia are all high-incidence areas for destructive tornadoes, and the lack of any direct meteorological data over the Gulf of Mexico has made objective analysis and prediction dif- ficult. To augment the conventional sur- face and upper air networks, use has been made of radar and satellite photographs. The processing and display of either method is still in its infancy; considerable experimenta- tion will be required to obtain con- tinuous readout of radar- and satel- lite-produced information. At present, neither the radar nor satellite output is woven into conventional analyses in a systematic and objective manner. Forecast Methods — Present meth- ods are largely subjective, drawing heavily on case studies and the ex- perience of the individual forecaster. This is slowly being replaced by objective, computer-oriented methods, partly dynamical and partly statisti- cal. (See Figure V-10) Considerable improvement is needed for either method. The most promising avenue for dynamical methods concerns the development of a fine-mesh primitive equation model for multi-layers. Such a model would be of limited value at this time because of the data limita- tions noted, but it will become in- creasingly important as the average spacing between stations is reduced. The statistical approach involves a search for predictors through the use of multiple-screening regression tech- niques. It has not been possible to gather all of the possible predictors Figure V-10 — SEVERE WEATHER WARNING TIME OF ECHO 2 EST. VEL. AT2115CST=:256/23 CLOSEST DIST. 3 SIGMA APPROACH AIRPORT AND DIR. TIME LIMITS 2139 CUSHING 12.5 N 2125 2154 2148 STROUD 23.5 N 2131 2205 2148 PAWNEE 12.4 S 2131 2205 2152 HOLDENVILLE 18.0 N 2133 2210 2200 ATOKA 21.3 N 2140 2221 2217 BRISTOW 25.2 N 2152 2242 The table illustrates an experimental severe weather warning of a thunderstorm cell moving from 256° at 23 knots. The warning gives the time of closest approach to airports near the forecast path. It also gives the distance and the direction of the echo from the airport. Finally, it estimates potential error of the forecast in terms of the time period of closest approach. This warning was prepared auto- matically by a computer using statistical properties of radar echoes such as those measured in Figures V-8 and V-9. along with tornado occurrences, so this approach will require further work. Research and Development — Com- paratively little research on forecasts is being performed in this country. In allied fields, considerable research and development is under way on hail suppression, doppler radar, LIDAR (light detection and ranging), and remote-sensing techniques. Im- proved equipment and techniques will have application to the warning prob- lem. Modeling Several theories have been ad- vanced to explain the Great Plains tornado. These theories do not, how- ever, explain the hurricane-induced tornado, the western U.S. tornado, or the waterspout. A great deal more work is needed in modeling tornado formation. Prediction Techniques The same problems apply to the warning as to the forecast. A vast majority of reported tornadoes do not come close enough to any of the reporting stations to be detected, ei- ther visually or by instruments. Radar Detection — The radar net- work is being expanded throughout the United States, using 10-centimeter radar. This is effective to 125 nautical miles in defining severe thunder- storms capable of producing torna- does, but even a highly skilled radar operator cannot clearly identify a tornado by radar or give a 15-minute forecast that a certain cloud will produce a tornado. Certain charac- teristic shapes provide some informa- tion on the probability of tornadoes, but the pattern is not present for every tornado. Instrument Detection — There are no mechanical methods at this writ- ing that can make an objective dis- tinction between the pressure fall or rise produced by a strong squall line and that produced by a tornado. Even if there were such a device, the spacing required to insure its useful- ness would be prohibitively expen- sive. Volunteer Spotters — Most warn- ing is based on a combination of 147 PART V — SEVERE STORMS radar detection and visual spotting, warning is a function of the spacing is needed on "steering methods" for usually performed by volunteers. of the spotters. tornadoes once they are known to This gives uneven results at best, exist. No work at all has been done since the ability of the spotter is as To be of maximum value a warning to determine how long a tornado will much a function of his zeal as any- should be as specific as possible with be in contact with the ground once thing else. The timeliness of the regard to area and time. More work it has been detected. 148 3. HAIL Hailstorm Research and Hail Suppression Hailstorms belong to those atmos- pheric phenomena whose life history originates and terminates in the mesoscale range — i.e., their size ranges from about 1 to 100 kilo- meters. Phenomena of this scale pre- sent great difficulties for observation and description, and the means and instrumentation for that purpose are only now being developed. Radar, the oldest tool of mesoscale observation, has been somewhat dis- appointing when quantitative data are required. A system that combines airborne radar with data derived from the aircraft's doppler navigation sys- tem has proved to be a powerful tool for storm studies. The radar helps to delineate the precipitation echo of the storm while the doppler system provides the wind vector at flight level. Thus, on circling the storm, the line integrals for divergence and vorticity can be solved, and these yield the inflow into the storm throughout its life history. The improved means of storm ob- servation have de-emphasized the classical approach to storm research. This approach attempts to find, through observation and deduction, one valid storm model that satisfies all hailstorms. The last such model was derived by Browning from radar observations of one storm in England. It was characterized by a slanted updraft and an echo-free vault — i.e., an area where the main updraft speed was concentrated and where, due to the high updraft speed, no large particles accumulated that would cause radar reflections. Hailstorm Characteristics Nowadays we know that hail- storms appear in many manifesta- tions. The energy source is always the latent energy of condensation, but in the exploitation of that energy the vertical wind profile appears to assume an important role. Over the Great Plains of the U.S., hailstorms usually travel from west to east. They can grow and form new cells from the leading (eastern) edge or from their trailing (western) edge; thus, they can actually grow from the rear. It appears that their updraft is usually upright and not slanted even under conditions of strong wind shear; more and more, they are re- garded as aerodynamic hindrances in the large-scale atmospheric flow re- gime, with the wind going around and over the storm. Thus, the up- draft tower may be eroded on the outside by the horizontal wind but remain undisturbed in the interior. The air intake into a growing cell is of the order of 10 cubic kilometers per minute. High wind velocity in the anvil level appears to be the mechanism that prevents early decay of the cell, since precipitation and liquid water are carried away from the cell and, consequently, do not fall back into and "suppress" the updraft. It has been shown that hailstorms occur with special frequency in jet- stream regions of the United States, Europe, and India and that the com- bination of convective storms and jet stream can produce a very efficient and abundant precipitating cloud sys- tem. There are indications that the effectively producing hailstorm is characterized by high latent instabil- ity, inflow from the right rear quad- rant, and strong wind shear aloft. Very poorly understood is the way hailstorms become organized. As yet, we do not know under what condi- tions many small storms or a few big ones form, what causes the storms sometimes to align themselves in rows and sometimes to form in clus- ters. It has been speculated that differences of surface temperature be- tween sunlight and shadowed areas may cause local seabreeze-type cir- culations which contribute to the organization of inflow areas. Some conditions lead to self- enhancement of storm intensity. For example, when the storm moves over its own precipitation area and en- trains moist air, the base level is lowered, which in turn increases the buoyancy. This will increase the in- flow into the storm, which then leads to an increased diameter of the up- draft column. This causes an increase of updraft speed for the same latent instability because the ratio between buoyancy forces and drag forces has shifted in favor of the buoyancy force. Theoretical Studies Theoretical studies of the dynamics of storms extend in two general di- rections: Analytical Studies — These studies deal with the influences of buoyancy and water-loading on updraft speed and radial divergence when the buoyancy term is compensated by the weight of the cloud and precipitation water. Essentially, this research aims at appraising the existence of an "accumulation level" of cloud water in the upper regions of the storm. According to Soviet scientists, the accumulation level is characterized by a high liquid-water content, since the local derivative of the updraft speed 149 PART V — SEVERE STORMS versus height is negative (£<•) above that level and positive below it. As long as the maximum updraft speed is greater than 10 meters per second, water drops will neither de- scend below the accumulation level nor ascend much above it. Therefore, liquid water may become trapped at a certain layer and provide conditions for the rapid growth of hailstones. While the existence of such a level is possible, the rapidly increasing water-loading will, for continuity rea- sons, cause a strongly divergent flow that discharges the accumulating wa- ter content radially in a short time. Numerical Studies — Several at- tempts are under way to expand one- or two-dimensional numerical cumu- lus-cloud models into convective storm models. Even two-dimensional models, however, are much too prim- itive for the simulation of a phe- nomenon as complex as a hailstorm. The best model to date appears to be a time-dependent, two-dimensional model developed by Orville; however, even this model puts severe strains on computer capacity and memory. There can be no question that these attempts are only first steps and that much research and data collection is required to make them realistic. Microphysical Studies Microphysical studies aim, partic- ularly, at an explanation of hailstone structure and the application of hail- stone features to explain the condi- tions under which it has grown. It is hoped that hailstones can be used as aerological sondes which even- tually may reveal their life history and, consequently, the environmental conditions inside the hail cloud. (See Figure V-ll) Here the investigator is confronted with complexities related to greatly varying growth conditions of ice due to accretion of supercooled water. The most thoroughly conceived the- ory has been developed by List from actual growth conditions in a hail wind tunnel. However, List gives consideration only to the accretion of supercooled cloud water; ice struc- tures resulting from the accretion of a mixed cloud (ice crystals and water droplets) or of aggregation of smaller hail or graupel have not been studied. The following general statements may be made with caution: Hailstone Structure — Most hail- stones show a hail embryo in their Figure V-1 1 — STRUCTURE OF HAILSTONE EMBRYOS At the heart of almost every hailstone there is a distinct growth unit 5-10 millimeters in diameter known as the embryo. The illustration shows the three most common types: (1) Conical embryos consist of opaque crystals larger than 2 millimeters in diameter, indicating formation between -20C and 0 C. These embryos fall in a stabilized position, blunt end downward, so they collect droplets on only one surface. This category represents about 60% of the hailstones studied. (2) Spherical embryos of clear ice (25% of the hailstones studied) consist of large crystals or a single crystal, indicating growth in clouds with temperatures above -20 C. Many of these embryos have cracks caused by the freezing of internal liquid water. (3) Spherical embryos of opaque ice (10% of the hailstones studied) have crystals of intermediate size and air bubbles showing no particular arrangement. They may have had a more complicated origin than other embryos, involving partial melting and refreezing or even collection of snow crystals. Because they tumble as they fall, they collect droplets equally on all surfaces. 150 HAI! growth center. This embryo is conical or spheroidal. It can be opaque or clear ice. It is usually well recogniz- able against the shell structure of the remaining stone. One may conclude that the life history of a hailstone can be organi- cally subdivided into two major pe- riods: (a) growth in a hail embryo during the development cloud stage of the hail cell, and (b) growth in a hail shell during the mature-hail-cell cloud stage. It is conceivable that the former occurs during the de- velopment phase of the cumulonim- bus or hail cell, the latter when the penetrative convection has been es- tablished and a strong supporting updraft has formed. Environmental Growth Condi- tions — On the basis of List's theory it is possible to derive four environ- mental growth conditions from typi- cal hailstone properties: 1. It is unlikely that hailstones are usually grown in the high water content of an accumula- tion level; if that were true, one should observe soft, spongy hailstones much more fre- quently. 2. It can be shown that hailstones with many alternating layers of clear and opaque ice may have grown at high levels in the cloud; at these levels, small altitude variations cause large variations of the growth con- ditions. 3. Hailstone structures that are homogeneous over a large part of the shell indicate that they have grown in an updraft with continuously increasing updraft speed. 4. The natural hailstone concen- tration is of the order of 1 to 10 per cubic meter. This con- centration effectively depletes the cloud water content, as was shown in 1960 by Iribarne and dePena, which gives hope that hailstones could be made smaller and less damaging through a slight artificial in- crease in the concentration of about two orders of magnitude. Amounts of seeding material needed to accomplish this are moderate. Hail-Suppression Experiments The problem of hail suppression is economic as well as scientific. One of the questions to be answered is: Does agriculture suffer sufficiently from hailstorms that prevention is necessary? Some people believe that, as long as we have a farm surplus and pay farmers for not planting certain crops, we do not need hail suppression. While this may be true now, in coming years we may need every bushel of farm crop for our food supply. This appears to be a good time, therefore, to begin a hail- suppression research program. Re- search must be emphasized, since too little is known about the hail mechanism to permit a realistic hail- suppression program to be conceived. Also, little is known about the rela- tive damage that is done by hail, water, and wind during a storm. The research phase need not be completed, however, before modifica- tion experiments can be thought of. On the contrary, the problem should be considered as a field program in experimental meteorology, where a well-conceived experiment with hail clouds is carried out with the poten- tial of observing a cause-and-effect relationship. Some hail clouds are more suited to such an experiment than others; for example, hail clouds growing from the rear edge should have a basically simpler structure than hail clouds that grow from the leading edge. Such clouds are also easier to observe, as they are not usually obscured by an overhanging anvil. The National Hail Research Ex- periment (NHRE) attempts to ac- complish exactly this ba research objectives and suppression operations — namely, to use aircraft, radar, and surface networks for a thorough study of the hailstorm simultaneously with a well-designed aircraft seeding program to which the storm's reaction is observable. The latter program cannot be conducted entirely without statistical control. Hail Suppression: Soviet Union Much information has been ob- tained from the operational hail- suppression experiments in the Soviet Union, specifically in the Caucasus. Several books have been published, and exchange visits between Soviet, American, and Canadian scientists have taken place, with many fruitful discussions, although it has not been possible to obtain a clear appraisal of the validity of the claims made by Soviet scientists. It appears that two major efforts are under way in the Soviet Union which differ basically in the means of delivering the seeding agent into the cloud. In one, guns and shells are used; in the other, rockets. While the guns have greater range and altitude and deliver 100 to 200 grams of the seeding agent (Agl or Pbln) by ex- plosion of the "warhead," the rockets can carry a larger amount of the agent and deliver by burning a pyro- technic mixture (3.2 kg). The rockets are somewhat more versatile in de- livery either on a ballistic curve through the storm or vertically inside the cloud when descending by para- chute. One of four current projects in the Soviet Union is carried out through the Academy of Sciences of the Georgian S.S.R. in the Alazani Valley of the Caucasus, with Kart- sivadze as the chief scientist. Another is conducted by the Hydromete- orological Service in Moldavia by Gaivoronskii and others. The third, and largest, project seems to be conducted by the High Altitude In- 151 PART V — SEVERE STORMS stitute of the Hydrometeorological Service in Nalchick, under the di- rection of Sulakvelidze. This proj- ect consists of hail-suppression ex- peditions in the northern Caucasus, Azerbaidjan, and Armenia. The fourth is also in the Georgian S.S.R. and is under the direction of Lomi- nadze. Rockets are used in the first two projects; guns are used exclu- sively in the last two. The Ministry of Agriculture furnishes the hardware and crews for the field projects. Scientific Bases — All of these ef- forts are based on the validity of the relationship N ( Ns ) RS = R where Rs is the mean-volume hail- stone radius after seeding, Rn is the mean-volume hail- stone radius without seed- ing, Nn is the hailstone concentra- tion without seeding, and Ns is the seeded hailstone con- centration. A physical justification for the validity of this relationship was given by Iribarne and dePena and con- firmed more recently by List and Lozowski. The most important find- ing of this theoretical work is that the water content of a hail cloud becomes effectively depleted by a small number of hailstones, of the order of 10 per cubic meter, so that even modest artificial increases of their concentration by two orders of magnitude can be expected to de- crease their size sufficiently to prevent damage. It is this recognition that brings hail-suppression experiments into the realm of physical realization and economic benefit. All experiments in the Soviet Union seem to be designed in similar fashion: hail forecast, radar analysis, identification of the hail-spawning area in the cloud, and delivery of the seeding agent into the hail cloud. Forecasting skill has been developed to the degree that special experiments can be carried out to prevent the development of impending hail, while others are conducted to stop hail al- ready falling. Reported Results — Soviet scien- tists state that more than one million hectares (3,900 square miles) were protected in 1966. Hail damage in the protected area was 3 to 5 times smaller than in the unprotected area, which means that the cost of pro- tection amounts to barely 2 or 3 percent of the value of the crops involved. For 1966, the total ex- penditure for protection was 980,000 rubles, and the computed economic effect was a saving of 24 million rubles. Gaivoronskii and others have also reported on hail-suppression experi- ments in Moldavia, near the Bulgar- ian eastern border. These experi- ments utilize "Oblaka" rockets, a type that has a caliber of 125 milli- meters, weighs 33 kilograms, holds 3,200 grams of PbL- as a pyrotechnic mixture, and delivers a total of 3 x 1016 nuclei at -10° centigrade. Maximum range and height are 12 and 9.5 kilometers, respectively. The authors state that, in 1967, only 551 hectares out of 100,000 hectares of crop were damaged compared with 4,784 hec- tares in the control area. A similar effort with rockets is being carried out by Kartsivadze. Evaluation — It appears from the literature that the work in the Soviet Union is already past the research phase and well into the operational stage. As tests in the research phase were not randomized, however, a firm statistical significance has not been established. It is possible that the discovery by Changnon of the oc- currence of individual, short hail- streaks rather than long hailswaths may invalidate some of the conclu- sions made by the experimenters. Thus, a hailstreak may terminate by itself, rather than as a result of the seeding action, before reaching the boundary of the protected area, and since there are no means of knowing this beforehand such a case is counted as a positive seeding result. These conditions clearly point to the great complexity of designing a randomized experiment that would yield a unique result in a relatively short time. There can be little doubt that the basic approach of the Russian sci- entists, to treat each hailstorm as an individual case, is appealing; at the least, it eliminates the great uncer- tainty of the diffusional process from surface generators to the storm. Hail Suppression: Switzerland The GROSSVERSUCH III hail-sup- pression experiment was conducted in Switzerland from 1957 to 1963 in the Canton Ticino. The experimental area appears to have been larger than the canton, since generators and rain- gauges were distributed over roughly 10,000 square kilometers, but the size of the area instrumented with 24 surface Agl generators (type un- specified) was only a minor part of about 4,000 square kilometers, one- half of which were in Italy. After many years of careful freezing-nuclei measurements in and downwind from Agl generator sources it was concluded that, in order to be effective, seeding from the ground must be concentrated in the regions and at the moment in which storms form. It would appear, however, that the analysis should only be performed for the area coin- ciding with the generator network. Since this was not done, conclusions reached in the experiment — to the effect that "there is little doubt that seeding has been very effective in in- creasing the number of hail days" — seem to be not entirely valid. Hail Suppression: France French efforts in operational hail suppression are also continuing. Des- 152 HAII. sens gives a 22.6 percent decrease of hail falls as an average over the eight- year period since the experiment be- gan. The French scientists are using surface Agl-acetone generators, of which 240 are distributed over 70,000 square kilometers. The generators are lighted 6V2 hours before the expected outbreak of hailstorm activity in or- der to load the air sufficiently with good freezing nuclei, which may not normally be possible. The operations in Switzerland (GROSSVERSUCH III) can be re- lated to those in France in regard to the density of the generator network. The results for GROSSVERSUCH III show an increase of the number of days of hail (and an increase of rain amount per seeded day), while Des- sens reports a decrease in hail dam- age. Of course, "days of hail" and "hail damage" are two parameters that need not be directly proportional. Hail Suppression: Kenya Final results are available for the hail-suppression experiment carried out from 1963 to 1967 in Kericho, Kenya. It was based on the firing of Italian antihail rockets from 13 firing positions within the Kitumbe Estate. In 1968 the rocket network was expanded to neighboring estates to a total of more than 30 stations. The rockets contain 800 grams of TNT and no Agl; their burst occurs at 2,000 to 2,400 meters above ground or at about the +2° cen- tigrade level. Rocket-firing begins when hail starts falling and continues until hail stops. In Kitumbe nearly 5,000 rockets were fired during 60 hail storms. Because of the consistency of the reduction of damage on Kitumbe dur- ing both periods, it seems unlikely that this was due to chance. (See Figure V-12) Five mechanisms have been suggested to explain why the experiment should work: (a) cavita- tion, (b) shock-induced freezing, (c) freezing due to adiabatic expansion, (d) introduction of ice nuclei, and (e) introduction of hygroscopic nuclei. Continuing Experimentation — Pre- liminary results have been obtained from continued experiments over tea estates in Kericho. Seeding was done at cloud base with pyrotechnic de- vices dispersing between 6 and 30 grams of Agl per minute; 247 seed- ing flights were carried out on 225 operational days. In the first season, 58 hail reports from within the tea groves were obtained from 670 seeded cells, against a historical background of 360 hail reports from 686 nonseeded cells. Damage per hail instance was 2,929 pounds with seed- ing and 7,130 pounds without seed- ing. The great frequency of storms seems to make this area an excellent natural laboratory. Hail Suppression: Italy The effort in Italy proceeds along two avenues. The first approach is scientific in character and entails a study of the hail phenomenon rather than of hail prevention. The project is carried out by the Institute for Atmospheric Physics of the National Research Council. The second ap- proach has been developed by farmer associations and the Ministry of Agriculture and Forests. The largest effort is that of exploding rockets inside the clouds when the hailstorm is overhead. The rockets carry 800 grams of TNT to altitudes of 1,000, 1,500, or 2,000 meters. In 1968, 96,000 of these rockets were fired in Italy. Plans are being made through the National Bureau of Elec- trical Energy for a project employing ground-based silver iodide burners of the type used by Dessens in France. Hail Suppression: United States In the United States, plans for a National Hail Suppression Field Test proceed slowly, while theoretical and applied research on the structure of hailstorms and the hailstone mech- anism progresses more rapidly. Proj- ect HAILSWATH, a loosely coordi- nated field experiment, was organized in the summer of 1966 in Rapid City, South Dakota. Twenty-three institu- tions participated in this endeavor, whose outstanding purpose was to explore the feasibility of a large joint operation involving, at times, as many as 12 aircraft. Hailstorms were seeded with dry ice and silver iodide according to a target-control area approach on 10 experimental days, but the results lack statistical sig- nificance. A review of various hail-suppres- sion projects in the United States makes it apparent that American hail-suppression activities can hardly be called successful. Figure V-12 — HAIL SUPPRESSION AT KERICHO, KENYA July 63 Sept 65 Control to to Period Aug 65 Sept 67 All estates without rockets 20 22 24 Kitumbe 18 3 4 Other rocket firing estates 24 22 11 The table shows the decrease in the average loss per hailstorm in kilograms per hectare at Kitumbe estate compared with other estates in the nearby area. 153 PART V — SEVERE STORMS Current Status of Hail Prevention Hail losses in the United States, including damage to property and agricultural crops, have been esti- mated at $200 million to $300 million annually. While damage from hail- storms can occur in nearly every state, major hail losses are concen- trated in a belt extending from west- ern Texas through the High Plains into Alberta, Canada. Most property owners respond to the hail risk by buying insurance, since damages by hail are typically covered in a homeowner's compre- hensive policy. However, insurance coverage is less satisfactory for agri- cultural crops, because of the high premiums required in regions of high hail hazard. Crop hail insurance pre- miums in the Great Plains can range up to 22 percent for a standard policy. During a period of crop surpluses, it may be debatable whether crop losses from hail justify any substan- tial research effort. However, from the point of view of the effects of hailstorms on society, and consider- ing the trauma of a hailstorm loss and the fact that destruction of prop- erty by hail is a net economic loss, investigation of artificial hail preven- tion deserves attention. In regions of high hail hazard, it appears likely that an ability to re- duce hail damage by as little as 5 or 10 percent would provide a net eco- nomic benefit. It is anticipated that hail reduction of 50 to 75 percent should be possible, with a resulting higher net economic benefit. Data Base: Large-Scale Field Experiments Attempts to prevent hail by cloud seeding were initiated shortly after the early experiments of Schaefer and Langmuir in the late 1940's. The projects were based mostly on the concept of reducing hailstone size through increases in the number of hailstone embryos. Silver iodide was the most common seeding agent and was frequently released from net- works of generators on the ground. The early projects in this country suffered from numerous handicaps, including a lack of knowledge of cloud processes and of resources for any significant evaluation studies. The early hail-suppression projects in the United States were conducted for commercial sponsors and em- ployed little or no statistical design. Some randomized experiments using ground-based generators were car- ried out in Argentina, Switzerland, and Germany. They yielded evidence that silver iodide could affect hail- storms, but that the effect could be unfavorable as well as favorable. Throughout the 1960's, under- standing of hail-formation processes was advanced through a number of extensive observational programs of hailstorms in the United States and abroad. The work carried out in the Soviet Union during this period is especially noteworthy, but observa- tional programs carried out in north- east Colorado also deserve mention. Improved understanding of hail growth processes led to more sophis- ticated systems for treatment. Seed- ing was increasingly carried out from aircraft and represented attempts to influence specific parts of a hail- bearing cloud rather than attempts to increase ice-nucleus concentrations throughout large volumes. This lo- calization of the seeding treatment reached its apex in the development in the Soviet Union of a system to introduce seeding agents into special regions within a cloud by means of artillery shells. There is increasing evidence that the seeding treatment used through- out the 1960's has been effective in eliminating hail from certain storms and reducing hail damage in other instances. Review of the evidence from a number of hail-prevention projects leads to the conclusion that the projects were successful in some instances. More recent results indi- cate substantial success in hail pre- vention in the United States, East Africa, France, and the Soviet Union. Indeed, a leading Soviet scientist is quoted as saying that "the problem of hail control is successfully solved." Mathematical Modeling During the past five years, sub- stantial advances have occurred in mathematical models of cumulus clouds. An ability to create realistic mathematical models of hailstorms would provide the basis for a better understanding of hail-formation proc- esses and mechanisms for hail pre- vention. Initial cloud-modeling attempts utilized relatively simple one-dimen- sional steady-state models. These simple models were helpful as fore- runners of more complex models which now simulate realistically the life history of a large rain shower. In addition to modeling the dy- namics and life history of the large cumulonimbus clouds, greater atten- tion has been given to the mathemati- cal simulation of individual hailstone growth. Early efforts at development of a mathematical formulation of hailstone growth are being continued. More recent work has given greater insight into the hailstone growth process, and shows that the primary region of hailstone growth appears to be in the higher and colder parts the hail-bearing clouds. (See Figure V-13) This information, derived from the mathematical analysis, is consistent with field observations. It is of particular importance since it 154 HAIL implies a basis for success in hail prevention by cloud seeding through the mechanism of drying out the re- gion of the cloud in which hailstones form. Although unresolved problems re- main concerning the position of hail growth with respect to the updraft maximum and the liquid-water con- centrations in hail-growth regions, a picture is beginning to emerge of a physically reasonable system for hail growth and hail prevention that is consistent with observations ob- tained from field projects. Prevailing Scientific Controversy There is no general agreement on the effectiveness of hail-prevention techniques. Skepticism concerning the claims of success in the Soviet Union and concerning the reality of ap- parent reductions in hail damage on hail-suppression projects in this coun- try loomed large in the development of current plans for hailstorm re- search in the United States. This is illustrated by the following extract from a planning document for the National Hail Research Experiment (NHRE): . . . This document i tirely concerned with a discussion of the need to complete success- fully a Hail Suppression Test Pro- gram, since it appears to us that a National Hail Modification Pro- gram is now premature. We must first determine if hailstorms can indeed be modified, and then learn if it is worth the effort. This point of view (that so little is known about hailstorms that the primary hail research effort should be so directed) is in conflict with the point of view that current knowledge Figure V-13 — A MIDWEST THUNDERSTORM Temp Height (°C) (kml -55 -50- •10 -40 -30--8 -20 12 10 20-. -10- 0--40 -37 The figure shows a single, mature convective storm of the midwestern U.S. which is apt to produce hailstones. A temperature and height scale are along the lefthand margin. Note the base of the cloud at 3.7 kilometers. The vertical wind speed profile is plotted over the cloud and indicates a maximum wind speed of 19 meters per second near the middle level of the cloud. If the maximum speed of the updraft exceeds the terminal velocity of the largest stable droplet, an accumulation zone of supercooled water forms because of the chain-reaction mechanism triggered by droplet breakup. The heavy line in the center section of the cloud is the 35-decibel contour as seen by radar. The accumulation zone is within this area. It is this area into which seeding material should be placed to be effective. 155 PART V — SEVERE STORMS provides a valid basis for initiating programs for application of current technology to hail prevention. Requirements for Scientific Activity Instrumentation — Current hail-re- search plans call for a substantial effort to develop sophisticated instru- mentation to attempt to obtain the detailed life history of hail-bearing clouds. This is considered necessary to create a complete physical model of such storms. Development of the instrumentation for this task will require a major effort. The NHRE five-year program involves large ex- penditures for radars, specialized air- craft, and large numbers of field personnel. The instrumentation and equip- ment required for a more modest effort at suppressing hail in a pre- designated target area would be less. Such an approach could provide a means of testing various hail-suppres- sion techniques, would provide a basis for attaining knowledge to an- swer extant scientific questions, and would also partially satisfy the view that attempts should be made to apply current technology without fur- ther delay for scientific investigation, which should continue concurrently. Applied Technology — Develop- ment of hail-suppression technology involves not only basic research, as is being planned under the current NHRE effort, but also efforts to apply the technology. Needs for basic research on hail appear to be covered adequately in present plans for NHRE. However, efforts in the development and application of hail- suppression technology are badly needed. An advantage of having several applications projects under way si- multaneously is that they can provide additional testing opportunities and opportunities for learning. An essen- tial requirement for optimum learning is to have a number of untreated cases, randomly selected, reserved as "control" cases. In several locations, local groups primarily concerned with applications and benefits from weather modification projects have agreed voluntarily to forgo treat- ment of a limited number of storm situations to provide such control cases. This willingness sets the stage for an opportunity for increased learning. However, local groups that have organized to apply hail-suppression technology have sometimes expressed the opinion that the scientific com- munity is more interested in perpetual programs of research than it is in ap- plication. Such groups may be in- clined to proceed on their own with premature operational programs that involve not only improper techniques but also foreclose future opportuni- ties for associated research efforts. It is, therefore, rather urgent that steps be taken to develop mechanisms for cooperation with such local groups while the opportunity to re- serve some untreated control cases still exists. If local groups begin hail- suppression programs from which they believe benefits are being ob- tained, the opportunity for coopera- tion and continued learning will disappear, since pressures will exist for treatment of all cases. Approximate Time-Scale — If the present NHRE program begins its activities on schedule in 1972, it should produce useful inputs to hail- suppression technology within ap- proximately five years. In addition, if steps are taken to work with local groups, useful inputs to hail-suppres- sion technology can also be antici- pated within three to five years of the start of such programs. Considering the time-scale for both basic research and applications pro- grams, it should be possible to obtain adequate knowledge to carry out hail- reduction efforts economically and routinely by the end of this decade. 156 4. LIGHTNING Basic Processes of Lightning About 2,000 thunderstorms are in progress over the whole earth at any given time. These storms produce a total of about 1,000 cloud-to-ground and 500 intracloud lightning dis- charges each second. It follows that there are over S million lightning discharges each day to earth, and about 5 times as many discharges within the clouds. Lightning is essentially a long electric spark. (See Figure V-14) The total electrical power dissipated by worldwide cloud-to-ground lightning is roughly equal to the total annual power consumption of the United States, about 500 billion watts. On the other hand, the energy from a single lightning flash to ground is only sufficient to light a 60-watt bulb for a few months. It is the high worldwide rate of lightning flashing that provides the high power levels. The electrical energy that generates lightning is transformed to sound energy (thunder), electromagnetic energy (including light and radio waves), and heat during the discharge process. The radio waves emitted by the hundreds of lightning dis- charges per second provide a world- wide noise background. The level at which many communications systems can operate is limited by this back- ground noise level. The radio waves emitted by a single close (say, closer than one mile) lightning discharge can also cause malfunction of sensi- tive electronic systems (particularly solid-state systems) such as are used in modern guided missiles. The heat generated by the lightning channel sets forest fires, ignites flam- mable materials, and can be a cause of individual death. Of the over 8 million discharges that hit the earth daily, very few cause damage. For example, most lightning to wooded areas does not cause forest fires. Still, there are about 10,000 forest fires a year in the United States at- tributable to lightning; and about 2,000 rural structures, roughly half of which are barns, are destroyed by lightning-induced fires each year. Lightning strikes about 500 U.S. commercial airliners per year. Most Figure V-14 — LIGHTNING (1) This photograph shows a normal cloud-to-ground lightning flash near Mount San Salvatore. Lugano, Switzerland. Note how the streamers from the main lightning strokes branch downward. (2) In this photograph, a tall tower on Mount San Salva- tore has triggered a lightning flash. Note how the streamers branch upward, indicat- ing a reverse situation from the normal lightning flash. 157 PART V — SEVERE STORMS strikes produce little if any damage, the lightning being confined to the plane's metal skin. Sometimes, how- ever, potentially serious structural damage, such as the melting of large holes, does occur. There have been two cases of the total destruction of aircraft which the Federal Aviation Administration has attributed to igni- tion of the aircrafts' fuel by lightning. The most recent case was that of a Pan American Boeing 707, which exploded over Elkton, Maryland, in December 1963 after being hit several times by lightning. In addition to the radio waves and heating effect produced by lightning, the direct electrical effects of light- ning are often deleterious. They can, for example, result in the disruption of electrical power, as is often the case when lightning strikes a power- transmission line or a power station. Direct electrical effects can also result in malfunction or destruction of criti- cal electronic equipment in aircraft and missiles. A spectacular example of the foregoing was the lightning- induced malfunction of the primary guidance system of the Apollo 12 moon vehicle. Further, individual deaths from lightning, about 200 per year in the United States, are pri- marily due to electrocution. Control of Lightning What can we do to control light- ning? Are there possible harmful consequences of such control? Let us look at the second question first and attempt to answer it by two examples. Suppose technology were advanced enough that we could stop lightning from occurring. What would the result be to forests and the at- mosphere? 1. If there were no lightning, would the incidence and de- structiveness of forest fires de- crease? In many cases, forest fires would be less common, but those that did occur would be more destructive. Lightning- induced forest fires and the forests have lived together in some sort of equilibrium for a a long time. (The oldest ar- cheological evidence of light- ning is dated at 500 million years ago.) There is now some evidence to indicate that fre- quent forest fires will keep a forest floor clean so that the fires that do occur are small and will not burn the trees. Further, in some cases, rela- tively clean forest floors may be necessary for the germina- tion of new trees. For example, Sequoia seedlings can germi- nate in ashes but are suppressed under a thick layer of needles such as would cover an un- hurried forest floor. Thus, it is not obvious that blind control of forest fires is desirable. 2. If the frequency of lightning were diminished, would there be an effect on the atmosphere? Nobody knows. Lightning cur- rents and other electrical cur- rents flowing in the atmosphere during thunderstorms deliver an electrical charge to the earth. An approximately equal charge (a balancing charge) is thought to be carried from the earth to the ionosphere in areas of fair weather by the ambient fair- weather electric field between the earth and the ionosphere. Changing the lightning fre- quency might upset this charge- transfer balance with a result- ant effect on the fair-weather field. The change in the fair- weather field might trigger further reactions. The study of the effects of light- ning on the environment is in its infancy. The control of lightning is not necessarily desirable unless the full consequences of that control are evaluated. Now, let us look at lightning con- trol. When "control" is mentioned it is reasonable to think either of (a) stopping lightning or (b) harnessing its power. To harness appreciable power from lightning would require a worldwide network which could tap energy from a reasonable fraction of the world's total discharges. Even if science were to devise an efficient way to tap energy from a lightning stroke (which it has not yet done), the construction and maintenance of some sort of worldwide network ap- pears at present to be impractical. On the other hand, stopping lightning from a given storm, or at least de- creasing its frequency, is certainly a practical goal, and some initial steps in this direction have been taken. For example, it has been experi- mentally demonstrated, although not to the satisfaction of everyone con- cerned, that cloud seeding can some- times decrease the number of light- nings produced by a thundercloud. Understanding of Lightning A number of photographic, elec- trical, spectroscopic, and acoustic measurements have been made on lightning. From these we have a reasonably good idea of the energies, currents, and charges involved in lightning, of the electromagnetic fields (radio waves, light, and so on) generated, of the velocities of propa- gation of the various luminous "streamer" processes by which the lightning discharge forms, and of the temperature, pressure, and types of particles comprising the discharge channel. In short, we have available both an observational description of how lightning works (e.g., the dis- charge is begun by a luminous leader which is first seen at the cloud base and moves toward ground in steps, as shown in Figure V-15) and most of the data needed for routine engi- neering applications (e.g., power-line design and lightning protection). A good deal of what we know about lightning has been determined in the United States in the past fifteen years. However, the total number of U.S. researchers primarily studying 158 NFNG Figure V-15 — THE INITIATION OF A LIGHTNING STROKE WA WW//////////////,. (Illustration Redrawn with Permission. BEK Technical Publications, Inc. Carnegie. Pa) The drawing shows the initiation of a stepped-leader from a cloud base. The time involved is about 50 millionths of a second. As the downward-moving leader gets close to the ground, upward-moving discharges meet it. A return stroke then propa- gates from the ground to the cloud. The time for the return stroke propagation is about 100 millionths of a second. Propagation is continuous until the charges are dissipated. lightning at any given time during this period has been only about ten, of which perhaps half have contrib- uted to our understanding of light- ning. As an example of the general lack of scientific interest in lightning phenomena, the first technical book on lightning was not published until 1969. While we have available a number of observational "facts" about light- ning, we do not understand lightning in detail. Areas of particular igno- rance are: (a) the initiation of light- ning in the cloud and (b) propaga- tion of lightning from cloud to ground. Unfortunately, these are just the areas in which a detailed under- standing is essential if lightning con- trol is to be practiced. It is important to know what we mean by a "detailed understanding." A "detailed understanding" implies a mathematical description or model of the lightning behavior. The mathe- matical model is adequate when it can predict the observed properties of lightning. The mathematical model can then be used to determine the effects on the lightning of altering various parameters of the model. For the case of lightning initiation, these parameters might be the am- bient temperature, ambient electric field, number of water drops per unit volume, etc. The predictions of the mathematical model must be tested by experiments. The results of these experiments can suggest changes in the model or can verify its validity. It follows that experi- ment and theory must advance to- gether to achieve a complete descrip- tion of the lightning phenomenon. The physics of lightning initiation and propagation is exceedingly com- plex. Some idea of its complexity can be gauged by noting that the proc- esses involved in electrical breakdown between a rod and a flat plate in the laboratory (an electric spark) are at present only vaguely understood. It appears that, despite about thirty years of experimental work, a real understanding of the laboratory spark will not be available until a mathe- matical description of the spark is forthcoming. Only recently have digital computers become available in a sufficient size that a mathematical solution to the spark problem is in principle possible. The Future Significant progress in our detailed understanding of lightning could probably be made in the next ten to fifteen years, although given the pres- ent level of scientific activity and ability in the lightning area, it is unlikely that this will be the case. Lightning research has been neither glamorous enough nor quantitative enough to attract the attention of many good graduate students or senior scientists. Several excellent ex- perimentalists are presently working in the lightning area, and their work needs to be continued and enlarged. More important to the goal of de- tailed understanding of lightning, however, is the need for mathemati- cally oriented scientists to become involved in the problems of lightning initiation and propagation. The mathematically oriented scientists and the experimentalists should work closely together in both the construc- tion of suitable mathematical models and in the planning and analysis of experiments. In studying lightning, the time- scale on which meaningful results can be expected is relatively long. From an experimental point of view, the necessity of staying in a given location for a long enough time to observe enough lightning to be able to compile statistically significant re- sults determines the time-scale of any particular lightning research pro- gram — generally, several years. The mathematical approach to lightning is exceedingly complex and thus must also take place on a time-scale of several years. With a coordinated work force of perhaps five senior 159 PART V — SEVERE STORMS theoreticians and fifteen senior ex- perimentalists (assuming, of course, that these researchers are equipped with the necessary skills), one might expect significant progress in our detailed understanding of lightning in the next ten to fifteen years. There is certainly no assurance of success in any lightning research. It is clear, however, that a successful effort to understand lightning must be a long- term effort. Reduction of Lightning Damage by Cloud Seeding Lightning is an important cause of forest fires throughout the world and especially in North America. In an average year, about 10,000 forest fires are ignited by lightning; in a severe season, the number may rise to 15,000. The problem is particularly acute in the western states, where lightning ignites over 70 percent of the forest fires. Here, hundreds of fires may be ignited in a single day, many of them in remote and inac- cessible regions. These peaks in oc- currence, along with existing heavy fire loads, tax fire-suppression agen- cies beyond reasonable limits of man- power and equipment. Fire-suppres- sion costs can be very high; direct costs may approach $100 million per year while losses of commercial tim- ber, watersheds, and other forest resources may be several times this amount. In addition to loss of human lives, lightning fires constitute a growing threat to homes, businesses, and recreational areas. Potential Modification Techniques What steps could be taken in weather modification to alleviate the lightning-fire problem? The most ob- vious is to reduce the number of cloud-to-ground discharges, particu- larly during periods of high fire danger. Those characteristics of dis- charges most likely to cause forest- fire ignition might be selectively mod- ified to decrease their fire-starting potential. Also, the amount of rain preceding or accompanying lightning could be increased in order to wet forest fuels and thus decrease the potential for fire ignition and spread. A Seeding Experiment — The large losses in natural resources each year caused by lightning-ignited forest fires has prompted the Forest Service of the U.S. Department of Agricul- ture to perform a series of experi- ments in the northern Rocky Moun- tains which are aimed at reducing fire-starting lightning strokes by massively seeding "dry" thunder- storms over the national forests. Following is a summary of results of the studies of lightning-fire ignition and lightning modification. The first systematic program of lightning modification was conducted in western Montana in the summers of 1060 and 1961. This two-year pilot experiment was designed to test the effect of seeding on lightning frequency and to evaluate lightning- counting and cloud-seeding methods in mountainous areas. Some 38 per- cent fewer ground discharges were recorded on seed days than on days when clouds were not seeded. Intra- cloud and total lightning were less by 8 and 21 percent, respectively, on seed days during the two-year period. Analysis of these data by a statistical test showed that, if seeding had no effect, differences of this magnitude would occur about one in four. Also, the experiment con- firmed the need to develop a contin- uous lightning-recording system that could resolve the small-scale details of individual lightning discharges. Subsequently, a continuous lightning- recording system and improved cloud- seeding generators were developed. Building a Data Base A new lightning-modification ex- periment was begun in 1965, with the first phase to last for three sum- mer seasons. The objectives were to gain additional information on the frequency and characteristics of lightning from mountain thunder- storms and to determine if there is a significant difference in the occur- rence and character of lightning from seeded and unseeded storms. It was not designed to confirm or reject a single mechanism by which lightning is modified by seeding. Rather, a primary objective was to build a body of observations of lightning from both seeded and unseeded storms and to use these data to build appropriate hypotheses and models for testing in future experiments. Appropriate statistical tests were in- cluded in the design of the experi- ments as a basis for evaluating dif- ferences attributable to treatment. Analysis of data on the basis of the life cycle of individual thunder- storms occurring in 1965-67 (14 no seed, 12 seeded storms) gave the following results at the given level of significance for two-tailed tests: 1. Sixty-six percent fewer cloud- to-ground discharges, 50 per- cent fewer intracloud dis- charges, and 54 percent less total storm lightning occurred during seeded storms than dur- ing the unseeded storms. 2. The maximum cloud-to-ground flash rate was less for seeded storms. Over a 5-minute inter- val, the maximum rate averaged 8.8 for unseeded storms and 5.0 for seeded storms; for 15- minute intervals, the maximum rate for unseeded storms aver- aged 17.7 as against 9.1 for seeded storms. 160 3. There was no difference in the average number of return strokes per discrete discharge (4.1 unseeded vs. 4.0 seeded). The average duration of dis- crete discharges (period be- tween first and last return stroke) decreased from 235 mil- liseconds for unseeded storms to 182 milliseconds for seeded storms. 5. The average duration of con- tinuing current in hybrid dis- charges decreased from 187 milliseconds for unseeded storms to 115 milliseconds for seeded storms. Inferences The results from the seeding ex- periments to date strongly suggest that lightning frequency and char- acteristics are modified by massive seeding with silver iodide freezing nuclei. While the physical mechanism by which massive seeding modifies lightning activity is not fully under- stood, there is evidence that the basic charging processes are altered by the seeding. Further, it has been established on the basis of direct measurements that hybrid discharges (lightning strokes that contain a con- tinuing current) may be responsible for most lightning-caused forest fires. Thus, a substantial reduction in the duration of the continuing-current portion of the hybrid discharge may have a large effect on the ability of an individual discharge to ignite fuels or to cause substantial damage. This change in the nature of the discharge may be more important than a change in the total amount of lightning that is produced by the storms. 161 PART VI PRECIPITATION AND REGIONAL WEATHER PHENOMENA 1. DROUGHT The Causes and Nature of Drought and its Prediction Drought is one of the manifesta- tions of the prevailing wind patterns (the general circulation). A few spe- cial remarks may clarify this mani- festation, and suggest further work necessary to understand and predict droughts. Virtually all large-scale droughts (like the Dust Bowl spells of the 1930's or the 1962-66 New England drought) are associated with slow and prevailing subsiding motions of air masses emanating from continental source regions. Since the air usually starts out dry, and the relative hu- midity declines as the air descends, cloud formation is inhibited — or, if clouds are formed, they are soon dissipated. The atmospheric circulations that lead to this subsidence are certain "centers of action," like the Bermuda High, which are linked to the plan- etary waves of the upper-level wester- lies. If these centers are displaced from their normal positions or are abnormally well developed, they of- ten introduce anomalously moist or dry air masses into certain regions of the temperate latitudes. More im- portant, these long waves interact with the cyclones along the polar front in such a way as to form and steer their course into or away from certain areas. In the areas relatively invulnerable to cyclones, the air de- scends, and if this process repeats time after time, a deficiency of rain- fall leading to drought may occur. In other areas where moist air is frequently forced to ascend, heavy rains occur. Therefore, drought in one area is usually associated with abundant precipitation elsewhere. For example, precipitation was heavy over the Central Plains during the 1962-66 drought in northeastern United States. After drought has been established in an area, it seems to have a tend- ency to persist and expand into ad- jacent areas. Although little is known about the physical mechanisms in- volved in this expansion and per- sistence, some circumstantial evi- dence suggests that numerous "feedback" processes are set in mo- tion which aggravate the situation. Among these are large-scale inter- actions between ocean and atmos- phere in which variations in ocean- surface temperature are produced by abnormal wind systems, and these in turn encourage further development of the same type of abnormal circu- lation. Then again, if an area such as the Central Plains is subject to dryness and heat in spring, the parched soil appears to influence sub- sequent air circulation and rainfall in a drought-extending sense. Finally, it should be pointed out that some of the most extensive droughts, like those of the 1930's Dust Bowl era, require compatibly placed centers of action over both the Atlantic and Pacific oceans. In view of the immense scale and complexity of drought-producing sys- tems, it is difficult for man to devise methods of eliminating or ameliorat- ing them. However, given global data of the extent described previ- ously, and the teamwork of oceanog- raphers, meteorologists, and soil scientists, it should be possible to understand the interaction of con- tinent, ocean, and atmosphere suf- ficiently so that reasonably accurate estimates of the beginnings and end- ings of droughts are possible. Ability to predict droughts would be of tremendous planning value. Unfortunately, encouragement for drought research comes only after a period of dryness has about run its course, because the return of normal or abundant precipitation quickly changes priorities to more urgent matters. Without continuing in- depth drought studies, humanity will always be unprepared to cope with the economic dislocations induced by unpredictable long dry spells. It has long been known that the general circulation of the atmosphere is such that alternating latitude belts of wetness and dryness tend to domi- nate the world system of climates. (See Figure VI-1) In connection with droughts, the important belts are: 1. The equatorial belt of wetness associated with ascending cur- rents in the zone where the trade winds from the southern and the northern hemisphere meet; 2. The subtropical belt of dryness associated with descending air motions in the so-called sub- tropical anticyclones; 3. The mid-latitude belt of wetness associated with traveling de- pressions and storms that de- velop in the zone of transition between warm and cold air masses — i.e., the "polar front." While the equatorial belt of wet- ness is more or less continuous around the world, the subtropical belt of dry- ness is disrupted by monsoon-like winds in the warm seasons and by polar-front disturbances in the cold season. As a result, rainfall is gen- erally adequate along subtropical east 165 PART VI — PRECIPITATION AND REGIONAL WEATHER PHENOMENA Figure VI-1 — ANNUAL WORLDWIDE PRECIPITATION I Over 80 inches annual mean rainfall I j\ I I -Mi 4I.I In SO in hi", [^] From 10 to 40 inches j Under 10 inches The map shows annual precipitation over the world compiled from land-station data and some ship and island observations. Isopleths over the ocean areas, which show large "dry" patches off western continental coastlines, are best guesses. coasts (e.g., Florida), while dryness typically prevails along subtropical west coasts (e.g., southern California) and in adjacent continents. Finally, the mid-latitude belt of wetness will be disrupted where mountain ranges (e.g., the Rocky Mountains) provide shelter against rain-bearing winds from nearby oceans. Between the semi-permanent cli- matic patterns, which do not change perceptibly, and the rather lively short-term patterns associated with traveling disturbances and storms, there exist regimes of long-lived anomalies superimposed on the gen- eral circulation. These anomalies are quasi-stationary or move very slowly, and their duration and intensity may vary within wide limits. Anomalies of this kind are always present, and when their duration and intensity ex- ceed certain limits of dryness, they become recognized as droughts. Most national weather services have estab- lished definitions of drought; al- though these are useful for record- keeping, administrative actions, and such, they do not reflect scientific principles. In the following, the word drought will be used in the meaning of an extensive period of excessive dryness. Research Findings There is some indication that cer- tain time-lag relationships exist. For example, Namias found that many summer droughts in the United States appear to be associated with changes in the upper atmosphere that begin to develop in the foregoing spring. There is a need here for more research to determine whether reliable two- way statistical relationships exist and are applicable to independent sets of data; if this should prove to be so, techniques for predicting the onset of individual droughts might be devel- oped. 166 DROUGHT The factors that determine the dur- ation of droughts have not been well explored and no predictive capability exists. The droughts that have re- ceived most attention are those that have affected agricultural operations — i.e., late spring and summer droughts. Some of these have been unable to survive the hardships of the winter following, but others have shown a tendency to recur the next spring or summer, and these pro- longed droughts are of great interest economically as well as scientifically. There is evidence to indicate that drought-producing systems tend to develop in families (rather than as in- dividuals), though each member may not qualify as a drought according to official definitions. For example, Namias found that drought-producing anticyclones over the agricultural heartland of North America have companion anticyclones on the Pacific as well as on the Atlantic. Drought- producing anticyclones in the lower atmosphere appear to be associated with distortions of the flow patterns through deep layers. Our knowledge of these conditions is meager; much firmer information could be provided through special analyses of existing data. Although an official drought may cover a relatively small region, the associated atmospheric processes must be studied in the context of the gen- eral circulation of the atmosphere, in- cluding the principal sources of heat and moisture. The Causes of Drought The above-mentioned findings — that drought-producing systems tend to occur in families and that individ- ual droughts may span one or more annual cycles — are of considerable scientific significance and hold out hope of progress toward prediction. These findings point toward the phy- sical processes that create the large- scale anomalies of which droughts are manifestations. Since extraterrestrial influences can safely be ruled out, it is clear that the forces, or energy sources, that bring about these anom- alies must develop within the earth- atmosphere system itself. Further- more, since an individual drought in middle and high latitudes (where the annual variation is large) may outlast an annual cycle, it is plausible that the underlying energy sources are rooted in the equatorial belt (where the an- nual change is small). Bjerknes has recently produced se- lected analyses that indicate, with a high degree of certainty, that the gen- eral circulations of the atmosphere in middle and high latitudes respond readily and significantly to energy in- puts resulting in variations in the ocean-atmosphere interactions in low latitudes. Of special importance is the transfer of heat and moisture from the oceans, and the freeing of latent heat by condensation in the air. The major site of interactions resulting in varying inputs of energy is the equa- torial belt from the west coast of South America to beyond the date line. Significant impulses can also be traced to the Humboldt Current, the Indian Ocean, and other areas. Bjerknes found that the upwellings of cool water, resulting from the vary- ing convergence of the trade winds, undergo changes that may be large at times, and these affect the rate at which energy is supplied to the atmos- phere in the equatorial belt. These in- puts are, in turn, exported via upper air currents as various forms of energy to the mid-latitude belt, where they bring about distortions of the flow patterns, dislocations of the storm tracks, and regional anomalies of different kinds. Of particular in- terest in connection with droughts is the tendency for more or less sta- tionary offshoots from the subtropical belt of dryness to disrupt the mid- latitude belt of wetness. Bjerknes' findings are of great interest and raise hopes for progress in long-range pre- diction and other applied areas. Research Aspects — It is clear from the foregoing discussion that our knowledge of drought is fragmentary and that much work remain done before adequate descriptions of individual or typical droughts can be provided. An individual drought must be recognized and described as a member of a family of anomalies, and its characteristics must be related to the evolution of these anomalies. Un- doubtedly, such descriptive studies will lead to greater insights into the underlying general mechanisms as well as the many local or regional factors that determine the severity of droughts. In the past, research on droughts has been conducted on an ad hoc basis, with emphasis on local or regional conditions. A concerted effort, making full use of available data and data-processing facilities, seems justified in terms of national re- quirements as well as available talent. Although the broad aspects of the causes of droughts appear to be un- derstandable on the basis of Bjerknes' findings, much work remains to be done to relate the evolution and the characteristics of atmospheric anom- alies to specific variations in the ap- propriate ocean-atmosphere interac- tions. Empirical studies should be matched with construction of models to simulate the behavior of the atmos- phere in response to observed or in- ferred ocean-atmosphere interactions. It is clear that the research oppor- tunities in this general area are highly promising. Data are available to sup- port analyses of many cases, with ex- tensions to longer time-spans. The present recognition of a need for im- proved understanding of our environ- ment and better management of our natural resources is likely to stimu- late application. The research is likely to appeal to young talent in several disciplines. And the research is likely to provide important inputs to the co- operative schemes of the International Decade of Ocean Exploration and the Global Atmospheric Research Pro- gram. 167 PART VI — PRECIPITATION AND REGIONAL WEATHER PHENOMENA The Prediction of Drought The National Weather Service is- sues monthly general forecasts of large-scale patterns of temperature and rainfall, and from such forecasts the likelihood of onset of drought dur- ing the month concerned may be in- ferred in general terms. At the present time, no specific techniques for pre- dicting drought exist. It is possible that a study of time-lag relationships for large areas could provide useful guidance. It is possible, too, that run- ning analyses of the conditions within the Pacific section of the equatorial belt and related studies of the re- sponses of the mid-latitude atmos- phere would provide useful prediction aids. Finally, the results of the above- mentioned studies are likely to be considerably sharpened through nu- merical experiments with dynamical simulation models. 168 2. PRECIPITATION MODIFICATION Artificial Alteration of Natural Precipitation The scientific basis of all efforts to modify precipitation artificially rests on manipulating the rates of reaction of natural precipitation mechanisms Our qualitative understanding of nat- ural precipitation mechanisms is in rather good shape. (See Figure VI-2) But our knowledge of the quantitative aspects of these processes is generally quite poor. There are several reasons for this state of affairs: 1. The process rate coefficients are inadequately known. 2. Several of the processes are competitive, so that small initial differences may give one of them an ever widening advan- tage. 3. The initial and boundary condi- tions are known to be important but are poorly understood and difficult to measure. Figure VI-2 — PRECIPITATION PROCESSES CONTINENTAL NUCLEI WATER VAPOR nucleation condensation ICE NUCLEI WATER VAPOR nucleation deposition MARITIME NUCLEI WATER VAPOR CIRRUS SEEDING NARROW CLOUD SPECTRA slow broadening by coalescence heterogeneous freezing SECONDARY ICE PARTICLES SECONDARY ICE PARTICLES ICE CRYSTALS - nucleation condensation BROAD CLOUD SPECTRA vapor deposition i SNOW CRYSTALS—- clumping SNOWFLAKES heterogeneous freezing "" _ FROZEN DROPS J X ICE PELLETS coalescence t DRIZZLE riming clumping SECONDARY ICE PARTICLES RIMED CRYSTALS RIMED FLAKES continued coalescence riming t GRAUPELS heterogeneous freezing wet and dry riming with drops and crystals partial melting I BRIGHT BAND RAIN SLEET (WARM) GRAUPELS HAIL SNOW GRAINS melting RAIN RIMED FLAKES SNOW PELLETS GRAUPELS ] * ^ partial melting I BRIGHT BAND continued coalescence SNOW ■ melting ■ GRAUPELS RAIN SNOW PELLETS SMALL HAIL ^ heterogeneous . freezing SLEET RAIN (WARM) In this flow chart, the precipitation process is seen to begin with water vapor and one of several different types of nuclei. Through various processes, the nuclei obtain vapor and grow. The final form of the precipitation depends on the environ- ment through which the precipitation falls. The various forms of precipitation that are observed in nature are listed at the bottom of the chart. By tracing their path upward through the chart, it is possible to determine the conditions necessary for their production. 169 PART VI — PRECIPITATION AND REGIONAL WEATHER PHENOMENA 4. There are several feedback loops whereby a change in the micro- physical character of a cloud parcel, as a result of precipita- tion development, feeds back into the energetics of the cloud and thereby alters the boundary conditions in which the precipi- tation processes operate. These feedback loops are largely unex- plored. They range in scale from the release of heat of phase change, causing a small cloud parcel to accelerate upward, thereby increasing its conden- sate load, to large-scale, long- range effects whereby a major change in the cloud system at one point induces adjustments in the atmosphere tens or hun- dreds of cloud-diameters away. Natural Nuclei and their Relation to Weather Modification Almost all U.S. efforts to change precipitation through cloud seeding (whether to increase, decrease, or re- distribute either rain or snow) rest on the observation that the normal be- havior of a cloud can be altered through the introduction of large numbers of suitable nuclei. There are two types of natural nuclei, serving two different func- tions, in natural clouds: 1. Cloud nuclei (small soluble par- ticles of the order of 0.1 to 3 microns in diameter), which serve as condensation centers for liquid cloud droplets. 2. Ice nuclei (probably clay min- erals about 1 micron in diam- eter, although the exact nature of these particles is still in ques- tion), which serve as centers of initiation of ice particles either by freezing drops or directly from the vapor. Ice nuclei are necessary for snow production. Snow generated aloft may melt inside a cloud on its way to the ground and land as rain. Rain may also be initiated by a few specially favorable cloud nuclei acting through an all-liquid process. The relative importance of the two known precipitation mechanisms is not fully worked out. However, it appears that the all-liquid process is more important in warmer seasons and in maritime air masses, whereas the ice-crystal mechanism is probably more important in colder seasons and in continental weather events. The ice-crystal mechanism of pre- cipitation development was the first precipitation process proposed. It ap- peared to explain most available ob- servations until the late 1940's, when meteorologists began to make meas- urements inside clouds and to examine them with radar. The all-liquid pre- cipitation mechanism was essentially unknown before about 1950; even to- day its relative importance is not clear. The common occurrence of super- cooled clouds was taken as evidence to show that concentrations of nat- ural ice nuclei were often insufficient for effective precipitation production. Proponents of seeding thus argued that, through the addition of artificial nuclei, one could enhance the effi- ciency of the ice-crystal mechanism and thereby increase rain at the ground. Technology quickly provided effi- cient tools for releasing large numbers of artificial ice nuclei. Present-day seeding generators, burning an ace- tone solution of silver iodide (Agl), yield effective ice nuclei concentra- tions of about 1013 to 1014 crystals per gram of Agl at —10° centigrade, increasing to about 101'' crystals per gram of Agl at —20° centigrade. This means that a single gram of Agl, if completely and properly dispersed, would be capable of seeding 100 cubic kilometers. Technology has not yet, however, produced adequate tools for measuring the concentrations of nat- ural ice nuclei. A more realistic, more scientific ap- proach to cloud seeding for altering precipitation is beginning to emerge. This approach recognizes, and at- tempts to relate, several interdepend- ent factors: 1. There are two known precipita- tion mechanisms, only one of which depends on ice nuclei and only one of which is readily accessible through present-day seeding technology. 2. The concentrations of natural nuclei, both cloud and ice par- ticles, and the internal structure of clouds of any given type differ importantly from time to time and place to place. For example, a substantial differ- ence between cloud spectra in maritime and continental cumuli is recognized as due to differ- ences in the cloud nuclei; ba- sically, it is this difference in drop spectra that gives mari- time clouds their propensity for warm rain. As a consequence of such differences, natural clouds differ markedly in their response to seeding. Not all responses to seeding are desirable. To give an ex- ample, Project WHITETOP found that Agl seeding of summertime cumulus clouds in Missouri may have decreased the rainfall by as much as 40 to 50 percent on days with south winds. 3. The development of precipita- tion takes considerable time, in many cases about the same as the lifetime of the cloud parcels that nurture the precipitation development. Thus, most seed- ing efforts attempt to alter the time required for precipitation development relative to the life of the cloud, or, alternatively, attempt to extend the life of the cloud by activating feed- back loops between changes in cloud microstructure and cloud 170 PRECIPITATIO I ' ICATION energetics. The seeding of small cumuli over Florida and over nearby ocean areas aims at complete glaciation of the clouds to secure the maximum release of latent heat of fusion, which in turn might cause greatly expanded cloud devel- opment. 4. The optimum number of ice particles (hence the seeding re- quirement, if any) depends in a complex way on the detailed nature of the cloud and the de- sired end product. For example the Bureau of Reclamation project in Colorado aims at regulating the number of snow crystals in the clouds to be the minimum required in order that their combined growth rate just uses up the liquid water of the cloud by the time the cloud reaches the crest of the moun- tain divide. A lesser number would permit cloud liquid water to pass over the divide and be evaporated. A larger number, and slower growth, might result in individual crystals being too small to fall out before crossing the divide. Requirements for Scientific Cloud Seeding The modern approach to cloud seeding is to couple the treatment method to the end object through specification of the target cloud and a knowledge of the intermediate phys- ical processes. To accomplish this re- quires elaborate systems for real-time measurement of deterministic meteor- ological factors, and real-time com- puter modeling of the physical proc- esses of the clouds to permit objective decisions as to when, where, and how to seed. Data Base and Related Technology — The data base on which to develop a scientific approach to cloud seeding is uneven. In some areas it is fairly good, in others almost totally lacking. The physical properties of cloud and precipitation particles, and the par- ticle-interaction coefficients, though incomplete, are sufficient for most purposes. Given an initial specifica- tion of cloud properties, one can make usable estimates of the growth of a limited number of precipitation par- ticles contained therein. Once the pre- cipitation particles become sufficiently numerous to interact appreciably, or in the ever present case of the inter- action of cloud drops, the bottleneck is not so much the lack of physical data as one of computer capability and mathematical devices to allow one to keep track of the large number of pos- sible interactions. A more serious difficulty is the gen- eral lack of data on the internal micro- structure of clouds as a function of cloud type, season, geography, and meteorological situation. Instruments for measuring ice and cloud nuclei are essentially laboratory devices and really not suitable for routine field use. Only recently have tools been developed for routine measurement of cloud-particle spectra. We have many measurements of nuclei and cloud- particle spectra from research proj- ects, but we still lack appropriate con- cepts for generalizing them in ways to permit useful extension to the un- measured cloud situation. Interactions and Downwind Effects — The feedback loops between the physics of particles inside clouds and the energetics of those clouds is al- most totally unexplored. One can per- ceive a definite effort in this area in cloud physics today. Important ad- vances are likely to come quickly in terms of the interactions inside single clouds. But the equally important problem of interaction between clouds and cloud systems on the mesoscale seems much more difficult. Such in- teractions are well known for the case of natural clouds. One should suspect them — indeed, there are signs point- ing to them — in the case of clouds altered by seeding. For example, measurements on Project WHITETOP indicated strongly that changes in rainfall due to seeding were accom panied by changes of opposite sign 50 to 100 miles downwind. Water and Energy Budgets of Clouds — An area of general meteor- ology of great importance to cloud seeding, and still inadequately ex- plored, concerns the water and energy budgets of clouds and cloud systems. Seeding to change precipitation pre- sumes to alter the water budget of the target cloud system, yet studies of the water and energy budgets of mesoscale weather systems are almost totally lacking. Braham carried out such a study for thunderstorms in 1952. A study of the water budget of the winter storms involved in the Bu- reau of Reclamation seeding project in Colorado is presently under way. Virtually no other mesoscale weather system has been so studied. The rea- sons for this are primarily the inade- quacy, for this purpose, of data from the National Weather Service and the great cost of obtaining additional data specifically for such studies. Yet cloud seeding can never be soundly based until we know in considerable detail the water budgets of both the natural and treated storms. Looking to the Future The preceding paragraphs are con- cerned mainly with topics in physical meteorology concerned with seeding clouds to alter the amount of precipi- tation at the ground. There are a number of other matters that must be resolved before such seeding can be adequate for public purposes. Some of these are scientific in nature, others are issues of economics, sociology, and public policy. Unanswered Questions — Among the most important issues to be faced are four unanswered scientific ques- tions: 1. Under what specific meteoro- logical conditions (including mi- crophysics and energetics of clouds) will a particular treat- 171 PART VI — PRECIPITATION AND REGIONAL WEATHER PHENOMENA merit technique result in a pre- dictable cloud response? 2. Which of the various possible cloud responses would be useful to society, in what ways, and under what conditions? 3. Given that a useful cloud re- sponse can be predicted from a particular treatment of some specific set of initial cloud con- ditions, are our abilities and tools for diagnosing the occur- rence of these conditions suf- ficient to permit exploitation of such treatment? In what time- space scale? In what economic framework? 4. What is the proper division of resources between : (a) basic research, where the sought-for end product en- hances knowledge about clouds and their physical response to seeding; (b) pilot projects, where the chief objective is assess- ment of the economics of a particular cloud-modifi- cation scheme; and (c) field operations, where the principal aim is to maxi- mize the field of a changed weather element? Projected Scientific Activity — Be- cause of the complexity of the at- mosphere and our limited knowledge about modifying it, it is likely that the skill in recognizing seeding op- portunities can be developed only from the results of a number of care- fully designed experimental projects aimed at testing seeding hypotheses in various types of weather situations in different parts of the country. Project WHITETOP and the Bureau of Reclamation Upper Colorado Pilot Project are examples of what these projects might look like, each of which will require from three to ten years. Until such studies are carried out, scientists will probably be unable to specify how much precipitation can be changed, under what conditions, and how often these conditions oc- cur. Technology is already at hand and scientific principles of experi- ment design are known. We must, however, be prepared to accept dis- advantages as well as advantages to the underlying population. Economic and Social Implications — The interactions of cloud seeding with society are clearly enormous, but they are hard to detail because we lack firm information as to how much and how often precipitation can be modi- lied, and also because most studies have emphasized the scientific as- pects with little regard for the eco- nomic, social, and political issues. Since there are few places in the United States where the economy is tied to a single economic enterprise, almost any change in precipitation is likely to disadvantage some while working to the advantage of others. We sorely need studies to learn the full scope of public cost and public benetit of changes in weather. We can start by using the natural vari- ability of weather and determine just how a departure of weather from long-term normality works its way through the economy of a region. Such studies — involving the collec- tive effort of sociologists, economists, and meteorologists — should be en- couraged. Even with such knowledge, one comes ultimately to the thorny is- sues of how we decide when and where to practice weather modifica- tion, and how the disadvantaged are to be compensated. Will insurance companies, for example, "pay off" in a region of cloud seeding if evidence develops that increasing rainfall also increases hail? The Status of Precipitation Management Research and operational weather- modification programs since the late 1940's have served to identify proce- dures that appear related to precipi- tation increases. At the same time, these results have indicated areas where real understanding and com- petence are insufficient. A number of cloud-seeding tech- niques have been developed. Ground- based seeding with silver iodide (Agl), whose crystal structure re- sembles that of ice (see Figure VI-3), is the most common technique, espe- cially for winter storms in moun- tainous terrain. The seeding ma- terial is carried aloft by vertical motion resulting from the instability of the air or from the lift due to the mountain barrier. One remaining fundamental problem involves diffu- sion of the seeding material. Proper seeding procedures require (a) that the proper number of nuclei reach the effective level in the cloud, and (b) that the effect of the seeding will be felt in the desired location on the ground. The diffusion process is a rather complex function of vertical temperature distribution and the three-dimensional wind field. Airborne seeding with silver iodide or crushed dry ice is frequently em- ployed with summer convective storms. The primary limitation of aerial operations is whether or not the aircraft can fly in weather condi- tions where seeding will be effective. Various experimental designs and statistical evaluation procedures have 172 PRECIPITATION \ Figure VI-3 — LATTICE STRUCTURES OF Agl AND ICE The models show the crystal structures of ice and silver iodide (Agl). In the model of Agl, the white spheres are iodide ions and the black spheres silver ions. Although the crystal structures of both molecules are similar, the lattice constant of Agl is 1.5% larger than that of ice. Partial compensation for the difference can be made by coprecipitating silver bromide (AgBr) with Agl and substituting Br for as many as 30% of the I atoms in the Agl crystal structure, which will produce a unit cell up to 0.5% smaller than that of pure Agl. been used. In retrospect, some of them were inadequate. Nevertheless, the early programs did show that cloud seeding has a tremendous po- tential. While the bulk of the activity in precipitation augmentation involves seeding clouds with artificial nuclei, other procedures have been proposed and are being studied. Modification of radiation processes is an example. If a large area (several acres or more) is covered with asphalt, the increased heating of the air immediately over the area can lead to strong convective currents, sufficient under some cir- cumstances to stimulate the precipita- tion process. Another possibility in- volves increasing the humidity high in the air so that more water would be available for the natural precipita- tion processes. Several ideas have been offered for extracting water from coastal stratus clouds. The obvious goal for weather- modification research, considered as a whole, is to find the best system for any given situation. However, the wide variety of conditions under which clouds and storms occur, cou- pled with the different types of to- pography over which these clouds develop, show that several, perhaps many, procedures must be available to get the best results from every situation. It is unlikely that the real world will ever see a truly "best" system for all conditions. A reason- able procedure, short of finding the absolute "best" way, is to put the available techniques, equipment, and instrumentation together in such a way that, under the existing condi- tions, the desired effect is maximized. In other words, optimize the available systems. What Constitutes a Precipitation Management System? A true precipitation-management system, even a crude and inefficient one, will have four major compo- nents: (a) a component to analyze present and expected water needs and water sources, as well as the anticipated effects of precipitation management on such factors as the economy and ecology of the area in question, and arrive at a decision to employ precipitation-management techniques; (b) a component to recog- nize a weather situation where the application of precipitation-manage- ment techniques would result in the desired effect and also, hopefully, those situations in which the result would be deleterious; (c) j compo- nent to select the proper treatment material and delivery system for the situation at hand; and (d) a com- ponent to assess the actual results of the treatment in terms of useful water on the ground, economic benefits and disbenefits, and environmental con- sequences. Analyzer Function — The first ac- tivity of an operational system is to determine when the application of precipitation-management techniques could contribute to the resolution of a water problem of a particular area. After the specific need is defined, the various potential sources of addi- tional water (e.g., the atmosphere, water mining, re-use) are examined to find the best way to fill the need. The effects of the application of precipitation-management techniques on the economics, ecology, and so- ciology of the area are examined. Another important consideration is whether or not the increased pre- cipitation would fall where a sub- stantial portion of it would eventually be usable. There are also legal ques- tions that must be looked at, such as ownership of the land being af- fected, ownership of the moisture being withdrawn, licensing and in- demnification procedures, and report- ing procedures. When all the available informa- tion has been considered, a decision is made. Precipitation-management techniques may be inappropriate for a variety of reasons, or they may be the only techniques available. Usu- ally, however, precipitation manage- ment will be used in addition to other methods of acquiring additional water. Recognition — Once a decision has been made to use weather modifica- tion in the solution of a problem, treatable situations must be identi- fied. Many of the necessary condi- tions for successful weather modifica- tion are known, at least qualitatively, but we do not yet know if these are sufficient conditions. 173 PART VI — PRECIPITATION AND REGIONAL WEATHER PHENOMENA One important factor in determin- ing whether or not a given weather situation is treatable is the number of natural nuclei. Nuclei are needed to convert vapor into liquid; other nuclei are needed to convert liquid into ice. The presence of ice crystals is con- sidered critical to precipitation for- mation in most clouds that occur in the middle latitudes. If liquid drop- lets are present at temperatures below freezing, a nuclei deficit is implied. Such a deficit in an otherwise suitable cloud can be overcome by the addi- tion of artificial nuclei. The addi- tional nuclei will convert some of the droplets into ice crystals, which will grow at the expense of the liquid droplets until they are large enough to fall out, thereby initiating or in- creasing precipitation. There are few routine observations of natural nuclei numbers, and most counts are made at the surface, not aloft where the clouds are. We have only rather crude notions of how many nuclei are needed in any given situation. Some of the other factors of im- portance in the treatability of a weather system are temperature structure, wind, liquid water content of the cloud, and cloud-droplet size spectra. Again, we have fairly good qualitative understanding of the role of each factor, but we do not com- pletely understand all the links in the physical chain of events leading to the desired result of the modification attempt. In addition, some of the pertinent factors are difficult to meas- ure. Still other factors may be im- portant in cloud treatability, but our knowledge of them in real cloud situations is too meager even for qualitative statements. In some situations, theory and em- pirical evidence have been united in mathematical models. These models simulate the atmosphere and can predict the response of the cloud to a given treatment. While the models available today are comparatively crude, they play a valuable role in enabling scientists to recognize treat- able situations. Treatment — After a situation is identified as treatable, the appropriate materials and techniques must be chosen. The most frequently used materials for weather-modification ac- tivities are Agl and dry ice, but many other substances have been used ex- perimentally (salt, lead iodide, cal- cium chloride, and a host of organics including metaldehyde, phlorogluci- nol, urea, and 1,5-dihydroxynaph- thalene). The temperature at which each of these agents becomes effective is fairly well known (see Figure VI-4), as is the particle-size requirement (for Agl, on the order of 0.1 micron). Clouds can be classified into two categories, cold and warm. Cold clouds are those with temperatures wholly or partly at or below 0° cen- tigrade. Warm clouds are those ev- erywhere warmer than 0U centigrade. Materials that affect cold clouds rarely have any effect on warm clouds. Thus, the treatment material must be matched to the situation. The object is to change the size and/or state of the cloud particles. Precipi- tation from warm clouds can be in- creased if the small droplets can be turned into big droplets. Hygroscopic materials should be effective in warm clouds. They are, in fact, being used experimentally, though it has proved difficult both to get the material ground to a small enough size to stay in the cloud long enough to be effective and to keep the particles dry until they are released to the atmosphere. Once a few drop- lets large enough to begin to fall are formed, coalescence should keep the process going until precipitation falls out of the cloud. Hygroscopic materials should also be effective in cold clouds, but mate- rials that initiate a phase change are more efficient. Some cold-cloud agents, such as dry ice, simply cool the air and the vapor and liquid in it to a temperature at which tiny ice crystals form spontaneously. This process is effective at air tempera- tures a few degrees below freezing Figure VI-4 — TEMPERATURE DEPENDENCE OF NUCLEATING AGENTS Substance Effective Temperature °C Carbon Dioxide 0 Agl -4 PbL, -6 Cud -7 Loam-Rugby, N.D. -8 NH4F -9 v2o5 -10 Loess-Hanford, Wash. -11 Cdl2 -12 Soil-Baggs, Wyo. -13 I2 -14 Ash-Crater Lake, Ore. -17 Dust-Phoenix, Ariz. -18 Kaolin-Ga. -23 Diatoms -31 Spores -36 The table lists some of the more prominent substances that are used as nucleating agents and the temperature at which they become effective as nuclei. 174 PRECII I or lower. Other materials, such as silver iodide, are known to be effec- tive, but why they work is not clearly understood. The crystal structure of Agl is quite similar to that of ice, and this was thought to be the rea- son for its effectiveness. Recent stud- ies suggest that pure Agl is a rather poor nucleating material, and that it must be contaminated with some other material to be useful in weather modification. Different methods are needed to deliver the various materials to the cloud. Dry ice is dropped into clouds, usually from an airplane. The size of the dry-ice pellets depends on the vertical thickness of the cloud. Silver iodide can be released from the air or from the ground. Ground releases rely on the horizontal and vertical airflow to carry the material to the cloud. One major problem is to confine the effects of treatment to a desig- nated target area. The point on the ground where the effects will be felt is determined by the point of release of the material, the concentration of the material at the release point, the diffusion of the material (a function of the three-dimensional wind field), the time required for the material to become effective once it is in the cloud, and the time required for the altered cloud characteristics to show up on the ground. The usual pro- cedure involves assumptions about mean values and average times, with reliance on the skill of the operator to integrate the various factors sub- jectively. Several mathematical mod- els have been developed that predict the area of effect; as these models, and the data they use, improve, tar- geting procedures should also im- prove. Despite the uncertainties in how the material works, how much is needed, and where and how it should be released, present capabilities are sufficient to warrant a certain number of operational precipitation-modifica- tion programs. In these cases, the areas to be affected are relatively small and the objectives sufficiently narrow so that the uncertainties can be taken into account in the program designs. Evaluation — The final phase of a functioning weather-modification system is evaluation of the results. Evaluation techniques include the standard statistical approaches: target vs. control; treat vs. no treat; ran- domized crossover, and so on. Both parametric and nonparametric statis- tics are used. A few new variations have been considered but are not being used except experimentally. Given a suitable experimental design, existing statistical evaluation pro- cedures are acceptable for programs that go on for several years and in which the evaluation can wait until the end of the program. Full evaluation includes not only the amount of precipitation produced but also the economic consequences of the activity and the effects on the social and biological environment. Current Scientific Status Large quantities of data at or near the earth's surface have been gath- ered from experimental areas. Upper- air data are generally insufficient in terms and frequency and density. Because most weather-modification activities are rather small and inde- pendent of one another, data gather- ing is not standardized with respect to time of observation, duration, precision, or reliability. Some of the data from commercial programs are not readily available. Perhaps the greatest limitation of the present data base is the scarcity of measurements of some of the important factors in precipitation augmentation, such as natural nuclei counts. Lack of suit- able instruments is, in part, respon- sible for this situation. Extra-Area Effects — While scien- tists have not had the quality data they would have liked, significant advances have occurred in the past few years. One interesting phenom- enon was recently recognized: In major field programs for increasing rain, changes in the precipitation pat- tern well outside the designated tar- get areas have been noted. The changes were patterns of negative and positive anomalies, but the in- creases were more substantial than the decreases. This suggests that some sort of dynamic effect is caused by cloud seeding, resulting in an average precipitation increase over a very large area. These effects are sometimes felt upwind and laterally as well as downwind of the target area. In at least one experiment, the precipitation of an entire area was increased, with target-area precipita- tion significantly greater even when compared with the precipitation-in- creased controls. How universal these effects are and under what conditions they occur are not clearly understood. The importance of this phenomenon in evaluation is obvious. The Significance of Cloud-Top Temperature — One of the most im- portant discoveries of the 1960's was identification of the importance of cloud-top temperature on the effec- tiveness of cloud seeding. Stratifica- tion of data by temperature indicates large precipitation increases from seeded winter orographic clouds when the temperature at or near the cloud top is between about — 15 and — 20° centigrade. When the temperature is — 25 or colder, precipitation de- creases from the same kind of clouds are observed. This suggests that suf- ficient natural nuclei have a negative influence on the precipitation process. Figure VI-5 summarizes some of the above data. Technological Improvements — Im- portant advances have been made in finding seeding materials other than silver iodide and dry ice. Many organic and inorganic materials have been studied in the field and in the laboratory. Several of the organics have been found superior to silver iodide in many respects, including cost, and work is progressing on 175 PART VI — PRECIPITATION AND REGIONAL WEATHER PHENOMENA Figure VI-5 — OPTIMUM SEEDING CONDITIONS Dn Figure Vl-5(1) Stat. Meth. Scale Change Sample Size Stratificati' Climax 1 Climax II Wolf Creek Climax 1 Climax II Wolf Creek -35 thru - •26 NP1 NP2 -31 -22 -46 -25 -15 -22 S32, N34 S18, N17 S43, N61 -25 thru - ■21 NP1 NP2 - 1 - 5 + 6 - 1 +22 +23 S53, N56 S23, N32 S57, N63 -20 thru - ■11 NP1 NP2 + 100 >+200 >+200 >+200 >+200 >+200 S35, N41 S20, N17 S64, N69 on Figure VI-5(2) Stat. Meth. i Scale Chanj ?e Sample Size Stratificati Climax 1 Climax II Wolf Creek Climax 1 Climax II Wolf Creek 0 to <0.7 NP1 NP2 <-50 <-50 <-50 <-50 -20 -24 S24, N21 S15, N12 S33, N33 0.7 to < 1.3 NP1 NP2 + 11 + 8 + 5 + 16 -14 -15 S76, N86 S36, N42 S58, N81 1.3 to <2.0 NP1 NP2 + 53 + 100 >+200 >+200 >+200 >+200 S20, N24 S10, N12 S73, N79 on Figure VI-5(3) Stat. Meth. Scale I Change Sample Size Stratificati Climax 1 Climax II Climax 1 Climax II 0 thru 11 NP1 NP2 +16 0 - 2 + 4 S25, N27 S15, N17 12 thru 16 NP1 NP2 +49 +20 + 9 +53 S27, N21 S16, N13 17 thru 21 NP1 NP2 <-50 -38 <-50 -20 S28, N28 S9, N12 22 thru 27 NP1 NP2 >+200 >+200 >+200 >+200 S26, N25 S12, N13 28 thru 43 NP1 NP2 -40 -39 -32 -32 S14, N30 S9, Nil The table presents stratified data from three sets of experiments in an effort to show what factors are important in seeding in Colorado during the winter. The optimum conditions are summarized as follows: (1) the 500 mb temperature should be between -11° and -20°C; (2) the computed vertical gradient of potential con- densate in the 700-500 mb layer should be 1.3 to 2.0 g/kg/100 mb; and (3) the 500 mb windspeed should be between 22 and 27 mps. The probability of each of these events has been computed, but is not presented here. making them suitable for operational use. Closely connected with new seed- ing materials are advances in delivery systems. Increased understanding of diffusion processes now puts posi- tioning of generators, either airborne or ground, on a more objective basis. New devices for producing nuclei permit more efficient use of nuclei material. Advances in radar tech- niques, coupled with improved under- standing of cloud characteristics and dispersion properties, permit safer and more effective use of aircraft in seeding operations. The use of rocket- launched, pyrotechnic seeding de- vices is receiving considerable atten- tion. Modeling — Mathematical models play an increasingly important role in both research and operational precipi- tation-augmentation programs. They are used operationally in recognizing treatable situations, in choosing par- ticular clouds to seed, in specifying the position of mobile generators so that the effect will be felt in the target area, and in specifying the area of effect from fixed generators. These models, developed from the basic laws of physics, are usually relatively simple, and can be run on moderate- size computers in near real-time. More sophisticated models have been used only for research pro- grams, in part because present- generation computers are not capable of handling them in the time-scale needed for operational use. The value of these models lies in suggesting effects to look for in the field and in suggesting factors to be studied in more detail. Three types (scales) of models are currently available: (a) microphysics models, which con- sider the formation and growth of water droplets and ice crystals; (b) dy- namic models, which consider motions and processes within the cloud (see Figure VI-6); and (c) airflow models, which consider cloud-forming proc- esses. None of these models alone is adequate to describe the complexities of precipitation augmentation; several attempts are being made, therefore, at combining or chaining them. Implications for Society Precipitation augmentation is be- coming an active partner with the other components of the water-re- sources system. In many parts of the nation, it may prove to be the most economical and socially acceptable method to increase usable water supplies. 176 PRECIPITATION Mi ': Figure VI-6 — SIMULATED EFFECT OF CLOUD SEEDING 10 p 1 1 1| 1 1 1 1 1 1 1 1 1 1 1 ii i| n 1 1 1 " 1 1 1 1 1 1 1 1 m i| m 1 1 1 1 1 1 1 m 1 1 1 1 1 1 1 1 1 1 1 1 " 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 9 U 6 - 5 4 r 3 - 2 1 CLOUD ICE / — s ll 1 1 1 ll II I ll 1 1 1 1 1 1 1 1 ll 1 1 1 1 1 HAIL(GRAUPEL) I m ■ I ■ n i I i i i i 1 i i i i I i l i l I l i l l I l l l I t n ir 0 12 3 4 KILOMETERS 10 11 12 13 14 15 16 17 18 19 20 io um|nu|inn minimum ii mnn|i ii hhii|ihhihhhihh mm i|in i|in i|m ipn i;m it 9 - 4 3 2 1 0 0 1 2 KILOMETERS 1 1 1 1 1 1 1 i 1 1 1 1 i i i i 1 1 i i 1 1 i i i i I i i t | [ i i i i 1 1 i 16 17 18 19 20 The two diagrams demonstrate a silver iodide seeding experiment done on computer- generated clouds. The numerical model simulates the growth of cumulus-type clouds forming over a mountain ridge in a domain 20 km wide and 10 km high. The general environmental airflow is from left to right. Clouds have formed to the left in the model and grown to form an anvil present at 7 km. The upper diagram shows the non-seeded case; the bottom, the seeded case. Seeding is simulated by changing all cloud liquid to cloud ice and the rain to precipitating ice at -10°C instead of — 25°C in the natural (non-seeded) case. The hail (or graupel) shown is in concen- trations greater than 1 gm of hail per kg of air. Rain is in concentrations greater than 1 gm per kg. These results demonstrate the effects of overseeding — less rain and less hail come from the seeded cloud since the large amounts of cloud ice that form are carried aloft and downwind in the anvil. 177 PART VI — PRECIPITATION AND REGIONAL WEATHER PHENOMENA Furthermore, precipitation augmen- tation affects other natural resources besides water. For example, an in- crease in precipitation will have an effect on the natural plant and animal communities in and around the target area. Extra water on the soil may bring additional lands into grazing capability, but it may also hasten the leaching of nutrients. The availabil- ity of additional water may cause changes in man's use of the land. He may change the kinds of crops he grows. He may reap greater harvests from smaller acreage. None of these effects, however, is expected to be large. Potential Benefits — The interac- tions between man, his institutions, and precipitation augmentation are important. The direct benefit of addi- tional precipitation is that it helps to assure an adequate supply of water for municipal, industrial, and agricul- tural uses. Secondary benefits include the generation of low-cost electricity and assistance in abating air and water pollution. Relatively small op- erational projects for water supply and power generation have existed for years. What is needed is an in- tegrated program in which many benefits can be realized from one ac- tivity. Potential Liabilities — Precipitation augmentation does have associated liabilities. A few people object to any deliberate tampering with nature, some on moral or religious grounds/ others simply on aesthetic grounds. Some of those who live or work in the target areas of augmentation op- erations could suffer financial loss, especially where the economic bene- fits are derived some distance away from the target area. Increased pre- cipitation in the form of snow could decrease the growing season and the tourist season. Erosion could increase slightly — although, alternatively, in- creased vegetation from the addi- tional moisture could cause erosion to decrease. Undesirable plant life may increase in certain areas. Increased snow could raise snow-removal costs (although an estimate made for the Colorado Rockies indicates no such effect for a 10 to 20 percent snow increase). Potential liabilities exist, at least in theory, in the possible extinc- tion of a few species of flora or fauna and in the modification of river chan- nels. The net value of precipitation augmentation must include determi- nations of the relative importance of man, nature, and their interaction. Legal Issues — Precipitation man- agement raises a variety of legal is- sues. Who owns the water in the atmosphere? How should losses re- lated to precipitation augmentation be compensated? How should opera- tions be regulated? How should the money to pay for operations be ac- quired (taxation by water district, state tax, federal funds, etc.)? Should research projects be treated differ- ently from operational projects with respect to liability? When water needs in one state can be helped by precipitation augmentation in an- other, who makes the decisions? Normative Issues — There are some reputable scientists who believe that, while seeding does affect certain cloud characteristics, there are too many conflicting results from cloud- seeding experiments to say that ob- served precipitation increases from seeded clouds were caused by the seeding. But the majority of scien- tists who question precipitation aug- mentation ask not "Does it work?" but "Should we use it?" In other words, precipitation augmentation, while far from perfected, is con- sidered by such scientists to be an operational reality. Precipitation aug- mentation today is thus in a position similar to that of nuclear power plants several years ago. Discussions center largely on the risks to people and the environment and on eco- nomic feasibility rather than on sci- entific capability. Answers to these questions await interdisciplinary stud- ies of real and hypothetical situations. Requirements for Scientific Activity The practical objective of current precipitation -augmentation research is the development of a precipitation- management system. The system in- cludes more than the ability to analyze water needs, recognize op- portunities, treat opportunities, and evaluate results. A fully developed system includes the ability to specify the results of treatment in advance with a high degree of confidence. It includes the ability to specify the areas that will be affected by the treatment, as well as the ability to assess beforehand the environmental consequences. Such systems need to be developed and thoroughly tested. To provide solid answers to the many unanswered questions of pre- cipitation augmentation, some im- proved instrumentation must be ac- quired. Some sort of standard nuclei counter is needed. Radar systems specifically designed for weather modification are needed to replace the surplus military equipment now be- ing used. A variety of airborne and surface remote-sensing devices would be useful. Especially needed are de- vices for determining the moisture distribution in the air from the sur- face to about 18,000 feet. Cloud- particle samplers are needed for cloud physics measurements. Several versions are available, but none pro- vides the scientist with all he needs to know. Accurate recognition of treatable situations is not yet a purely objective procedure. Better definition of the essential weather conditions is needed. Factors such as moisture flux are not easily measured on the scales needed for precipitation-augmentation proj- ects. Mathematical models and the computers to run them should be an integral part of the recognition sys- tem. Improved instrumentation will be needed to acquire the data for the system. The search for more effective treat- ment techniques must go forward. 178 PRECI Figure VI-7 — CONCENTRATION OF ICE NUCLEI IN A CITY The diagram shows the concentration of ice nuclei observed in Seattle. Washington, from 1 July to 3 November 1968. The scale gives the numbers of ice nuclei per 300 liters of air active at — 21 °C. The concentrations measured in the city were six times greater than the concentrations of nuclei measured at two unpolluted non- urban sites. From the plot of the concentrations on the wind rose, it is possible to deduce that there are sources of nuclei SW and SSW of the sampling site, which was in the northeastern part of the city. Analyses show that man-made sources of ice nuclei dominate over natural ones. Just what effect these nuclei have on the microstructure of clouds, and the development of precipitation, is not known, although studies in a growing number of cities seem to show that precipitation increases downwind of industrial areas. Less expensive and more readily avail- able materials are needed. Seeding materials that have beneficial side effects (such as fertilizing character- istics) or no side effects are desirable. More precise delivery techniques are needed so that the results of the treat- ment can be properly targeted and so that the optimum effect can be achieved. Better specification of the extra- area effects recently discovered is necessary for both targeting and eval- uation. The causes of the extra-area effects need to be understood so that the recognition and treatment systems can take the effects into considera- tion. Inadvertent modification of clouds by atmospheric pollutants is another vital but little understood issue. (See Figure VI-7) In some situations, inadvertent modification can be controlled. In others, it cannot be controlled but can be considered as a factor in the precipitation-aug- mentation system. Similarly impor- tant are the interactions between two or more neighboring augmentation projects. Advanced studies of both the posi- tive and negative interactions of pre- cipitation augmentation with other systems need to be carried out. Fac- tors in the natural environment will be affected by changes in precipi- tation. Short- and long-term con- sequences must be assessed from scientific, economic, and cultural view- points. The studies should not be limited to just the more obvious is- sues, such as ecological effects. The studies should consider the entire environmental system, which in- cludes man. Increasing interest in the environ- ment by both the scientific commu- nity and concerned citizens' groups argues for a more deliberate study of the environment as a system. Much literature has been circulated recently suggesting our impending doom if the quality of the environment con- tinues to deteriorate. Other studies have shown that severe water short- ages will be widespread by the year 2000. While some of these state- ments may not be rigorously based on fact, they do suggest the impor- tance of early development of a tech- nology that can play a role in en- hancing both the quality and quantity of the water portion of the envi- ronment. How rapidly the fully devel- oped precipitation-augmentation sys- tem described above can be made available is in part a function of the level of effort. The first such system could be operational by 1975. This system will be effective for win- ter orographic storm situations in sparsely populated, high-elevation areas. Shortly thereafter, a similar system for convective clouds could be operational. Through evolutionary processes, systems for other cloud situations, and improved versions of the first, could be available by the 1980's. 179 PART VI — PRECIPITATION AND REGIONAL WEATHER PHENOMENA 3. FOG Modification of Warm and Cold Fog The principal impetus for the de- velopment of methods for modifying fog has come from civil and military aviation. Despite improvements in instrument-landing techniques, dense fog over an airport severely restricts or prevents aircraft landings and takeoffs. Such occasions, even if they last only a few hours, impose sub- stantial financial penalties on the air- lines, cause inconvenience and loss to the traveling public, and delay or abort military missions. Dense fog is also a serious hazard for marine and surface transportation. (See Fig- ure VI-8) On the other hand, fog is beneficial in certain forested regions in which the fog-drip from the trees supplies significant moisture. The time- and space-scales of fog and its frequency of occurrence are all small enough that no large-scale changes of climate appear likely even if all fogs were to be dissipated. However, the climate of certain local areas with a high incidence of fog would certainly be changed if the fog were eliminated. Cold Fog Modification of supercooled, or "cold," fogs by seeding them with ice nucleants has developed to the point of operational use at a number of airports where such fogs are rela- tively frequent. The scientific basis for modifying supercooled fogs is well established; the remaining prob- lems involve the engineering of reli- able and economical operational equipment and procedures. Nucleants — Cold fogs are seldom supercooled by more than a few de- grees centigrade and, therefore, the Figure VI-8 — A DRIVING HAZARD The photograph shows a section of an interstate highway running through the valleys of central Pennsylvania. The valley in the foreground is clear, with excellent driving conditions. Once the driver enters the gap between the valleys, however, visibility begins to decrease until it reaches near zero. Although a local phenomenon, this condition causes many accidents each year. ice nucleants must have the highest possible threshold-activation temper- ature. Dry-ice pellets and liquefied propane, carbon dioxide, and freon have typically been chosen to meet this condition. Silver iodide is not expected to be effective above — 5 centigrade. Consideration should be given to the use of certain organic nucleants such as urea and phloro- glucinal, which have been reported to have relatively high activation temperatures. Dispensing Methods — To be effec- tive, the nucleants must be distrib- uted fairly uniformly through the volume of fog to be modified. The earliest, and still the most effective, procedure is to distribute dry-ice pel- ets from aircraft flying above the fog; vertical distribution is assured by the rapid fall of the pellets through the fog. Nucleants in the form of fine particles or liquefied gases must be introduced directly into the fog, which may involve hazardous flight levels. The costs of aircraft seeding and the limited storage life of dry ice have led to the development of ground-based dispensers. Liquefied refrigerant gases are commonly used, often with fans or blowers to dis- tribute the resulting ice crystals through the fog. Fog is almost always accompanied by a wind drift, and the location and timing of the seeding operation must be selected so that the clearing moves over the airport at the desired time. This requires timely wind ob- servations, precise navigation for airborne seeding, or extensive arrays of fixed seeding dispensers. A wind shift during the operation may cause the clearing to miss the airport. Cost Considerations — Operational successes in the clearing of cold fog 180 have been reported by the U.S. Air Force in West Germany and Alaska, by Orly Airport in Paris, and at several commercial airports in north- western United States. Cold fog at most American airports is so infre- quent, however, that the standby cost of a cold-fog modification system probably cannot be justified. (It should be noted that the ice fogs that form in cold regions such as Alaska cannot be modified by seeding with ice nucleants.) Warm Fog Warm fog is much more common than cold fog. Many methods have been proposed over the years for modifying warm fog, but those that have shown significant success all in- volve the evaporation of the fog drops. The evaporation may be achieved by heating the air, by dis- tributing hygroscopic particles in the fog, or by forcibly mixing the fog with the drier and/or warmer air above the fog layer. Heating was employed at military airfields in England during World War II with considerable operational success. This so-called FIDO (Fog In- vestigation and Dispersal Operation) method was further developed at Ar- eata, California, after the war, and an operational system was installed at Los Angeles Airport. Moderate suc- cess was claimed, but the method was abandoned because of the large amounts of fuel required and the psychological and safety hazards of operating aircraft between two lines of flames. The fundamental unsolved prob- lem of thermal-fog modification is the uniform distribution of heating throughout the fog. In a typical fog, heating sufficient to raise the air temperature by about 1° centigrade will cause the fog to evaporate in a short time. Arrays of point heat sources, particularly linear arrays, can be expected to lead to convection, non-uniform heating, escape of heated air aloft, and horizontal convergence of fog near the surface. The U.S. Air Force has had some success using jet aircraft on either side of a runway as heat sources. Further engineering developments aimed at providing reasonably uniform heating by means of blower-heaters specifically de- signed for the task may be worth- while in view of the basic attractive- ness of thermal-fog modification. Hygroscopic particles introduced into fog grow by condensation, thereby reducing the relative hu- midity and leading to the evaporation of the fog drops. This transfer of the liquid water to a small number of larger solution droplets leads to an improvement in visibility in the fog. More complete clearing occurs as the solution droplets fall out under the action of gravity. Hygroscopic particles act something like ice crys- tals in a cold fog, with the important difference that the equilibrium vapor- pressure over the solution droplets rises rapidly as the droplet is diluted, approaching that of pure water. To minimize the total quantity of hygroscopic material required to modify a fog, the hygroscopic parti- cles should be as small as possible, consistent with the requirements that they be large compared to the fog drops and that they fall out of the fog in a reasonable time. Since the solution droplets become diluted as they fall, the deeper the fog the larger must be the initial size of the hygroscopic particles. When the depth of the fog is more than a few hundred meters, accretion of the fog drops by the solution becomes an im- portant mechanism in the lower por- tion of the fog. Mathematical models of the modi- fication of warm fog by hygroscopic particles have been devised and used to guide field experiments. The the- ory of the growth of hygroscopic particles and the evaporation of fog drops is well established. Reasonably adequate information is available on the drop-size spectra and liquid water content of natural fogs. Tur- bulent diffusion is arbitrarily intro- duced on the basis of a few estimates of the eddy-diffusion coefficient in fogs. However, these mathematical models are static in that they do not model the natural processes that form and dissipate fog. Dynamical models must be developed that incorporate these processes. Among other ad- vantages, such models should yield the characteristic time of the fog- formation process. It seems evident that any artificial modification must be accomplished in a time that is short compared to this characteristic time of fog formation. This is of the utmost importance in the design of fog-modification experiments. In field experiments, hygroscopic particles have been released from aircraft flying above the fog. The usual assumption that the trailing vortices uniformlv distribute the par- ticles in the horizontal is highly questionable. Failure to achieve uni- form distribution of the seeding par- ticles is probably one of the principal causes of unsatisfactory modification experiments. A non-uniform distrib- ution can be countered only by in- creasing the total amount released to insure that there is an adequate con- centration everywhere. A closely re- lated problem is the marked tendency of the carefully sized hygroscopic particles to emerge in clumps. Imag- inative engineering design is needed to solve these problems, and nothing is more important at the present time. Air Mixing — Mechanical mixing of the warmer and/or drier air above a relatively thin fog layer will usually cause the fog to evaporate. The U.S. Air Force has produced cleared lanes by utilizing the strong downwash from helicopters; this technique is effective only in shallow fogs, how- ever. The cost/effectiveness ratio is probably large, but it may be justified for certain military purposes when the helicopters are available. 181 PART VI — PRECIPITATION AND REGIONAL WEATHER PHENOMENA Summary In summary, the modification of cold fogs with ice nucleants is an operational success, and further en- gineering improvements are to be expected; but there are only a few regions where the frequency of cold fogs is sufficiently high to justify the expense of a permanent installation. Warm-fog modification by heat or by seeding with hygroscopic particles is achievable in the relatively near future. The requirements for success are more adequate numerical models of fog and, most importantly, imagi- native engineering design so that the assumptions made in the experi- mental design can be realized in practice. However, it remains true today, as thirty years ago, that the total cost of warm-fog modification will be high enough to discourage its extensive application. Some recent benefit/cost figures are shown in Fig- ure VI-9. Figure VI-9 — RESULTS OF FOG-SEEDING PROGRAMS Air Cancellations Diversions Station Delays Avoided Avoided Avoided Cost Benefit Benefit^ Cost Los Angeles* 60 Hrs. 22 60 $63,000. $129,790. 2.1 Seattle* 50 21 50 34,500. 96,481. 2.8 Salt Lake City 50 50 27 5,800. 63,650. 11.0 Spokane 25 73 25 4,000. 28,141. 7.0 Medford 7.5 35 15 1,200. 14,970. 12.5 Boise 1 — 2 2,600. 2,157. 0.8 Omaha 6 1 — 2,300. 2,988. 1.3 Des Moines Total 3.5 2 204 "179 300. $118,300. 1,793. $339,970. 6.0 2.9 203 Hrs. *Cold fog; all other stations are warm fog case; The table lists the operational benefits versus costs experienced by United Airlines during the winter of 1969-70. Benefits have been calculated as monies that would have been spent were fog dispersal not available or unsuccessful. Cost of delays were computed from crew salaries, aircraft maintenance, and fuel and oil costs. Diversion costs included alternate ground transportation, meal and hotel costs, and overtime charges for ground personnel. Not included were intangibles or incomputables such as maintenance dislocation, ferrying equipment, need for reserve aircraft, and mispositioning of flight crews when flights were diverted. Also not included is the cost of customer inconvenience when fog disrupts operations. It is of interest to note that benefits were twice the costs of the program at Los Angeles even though fog was successfully dispersed in only 32% of the cases. Fog Dispersal Techniques To assess the present state of fog- dispersal techniques and define the work to be done, it is necessary to consider three types of fog. Ice Fog This type of fog is an increasing problem for aviation and other forms of transportation in a few high-alti- tude localities. Comparatively little research has been done to develop economical methods of combating ice fog. The only technique available at present is the brute-force method of applying heat to evaporate it. Fur- ther research is required to assist in the development of more efficient means of thinning or dispersing this type of fog. Supercooled (Cold) Fog In the contiguous United States, approximately 5 percent of the dense fogs that close airports to opera- tions are of the cold type. In more northerly latitudes, the percentage is higher during the winter. Other forms of transportation are equally affected when visibility drops below one-half mile, but the economic im- pact is probably not as great as it is on aviation. Dry-Ice Dispersing Techniques — Dispersal of cold fog by seeding crushed dry ice from light aircraft is an operational reality at approxi- mately a dozen airports in the United States. Some of these programs have been established each winter since 1962. The physical changes that 182 occur are well understood, stemming from the research of Schaefer, Lang- muir, and Vonnegut in 1946. Al- though the dry-ice technique is theoretically effective in converting supercooled water to ice crystals only at temperatures colder than —4° cen- tigrade, operational experience has demonstrated unequivocally that this technique is effective up to 0 centi- grade through proper sizing of the dry-ice pellets and proper control of the seeding rates for the conditions prevailing. This method of dispersing cold fog is about 80 percent effective. The failures that do occur are primarily related to operational problems such as miscalculating wind drift, which results in the cleared area moving off target. Occasionally, too, the tech- nique is stretched beyond the capa- bility of the physical reactions to take place, typically in supercooled fog decks whose upper layers are several degrees warmer than 0 centigrade. Ground Dispensing Methods — Be- cause of such operational problems and the complex logistics that are required in dispersing an airport fog by means of aircraft, a ground dis- pensing system, which employs essen- tially the same physical principles, is more desirable. Liquid propane has been used effectively as the seeding agent; it has reached a degree of sophistication in France, where con- trol of supercooled fogs at Orly Air- port is completely automated through the use of seventy fixed dispenser heads deployed around the target area. Liquid propane has been used operationally to combat cold fogs in the United States, but, primarily for economic reasons, the technology has never been developed beyond the use of a few portable dispensing units. Researchers have suggested that liquid propane and other cryogenics, in addition to providing the cooling mechanism, also alter the fog drop- lets through a clathration process. Since this latter process may increase the effectiveness of liquid propane in fog temperatures several degrees warmer than 0° centigrade, further investigation is warranted. Many air- ports are subjected to dense winter fogs with characteristic temperatures slightly warmer than freezing. De- velopment of this clathration process would pay off in benefits at many airports that cannot support the more expensive warm-fog dispersal programs. Warm Fog Since all but about 5 percent of the dense fog that closes airports and cripples other forms of transporta- tion in the populated latitudes is of the warm type, it would be expected that there has been some preoccupa- tion with measures to alleviate the warm-fog problem. Formal research into fog physics and development of laboratory techniques for dispersing fog have, however, been under way less than forty years. Out of desper- ation, some brute-force methods for evaporating fog have been under- taken where economics was not a factor. Houghton's work at the Massachu- setts Institute of Technology in the 1930's was the first formal research aimed at fog dispersal. A number of other studies on warm fog were subsequently undertaken by federal military and civilian agencies, but until the 1960's none of the fog- modification concepts was applied to routine commercial or military activi- ties. Economics, problems of logistics, or deleterious effects on the environ- ment were the deterrents. Modern Techniques — At least one installation of a refined thermal sys- tem for evaporating fog at a busy airport is planned for 1972. Other thermal methods that utilize energy more efficiently are under develop- ment. All of these systems are expen- sive and will probably be limited to application at major airports or other sites where the economic pressure of fog paralysis is high. For two years, warm fog has been regularly dispersed at a few U.S. air- ports through chemical seeding tech- niques that had been partially con- firmed by fog physics research and laboratory testing. This approach is feasible, and is producing economic benefits exceeding costs of the pro- grams by a factor of about 3 to 1; but it is considered in the developmental stage because aircraft dispensing is required. For full reliability and opti- mum benefit/cost ratios, a ground dispensing system must be developed that will use the most effective mate- rials. A number of promising con- cepts have been conceived and some have been laboratory tested. Further development work is required, but success will depend on better basic knowledge of fog makeup than we have today. Basic Warm-Fog Physics — Suffi- cient knowledge of fog physics exists to disperse warm fog with heat. The more attractive and economically feasible approaches to warm-fog dis- persal, which do not employ heat, require more basic physical knowl- edge in order to develop the most efficient system. Recent research involving the use of hygroscopic materials as seeding agents has provided some much- needed knowledge about fog, but there are still some baffling blind spots. This new knowledge came fif- teen years after successful feasibility tests were conducted, using the same principle, but which were not con- tinued because of logistic problems. It is hoped that another long delay will not develop before we can ex- plain, for example, why polymers, surfactants, and other substances, when diffused properly, produce posi- tive results, apparently through a strong ionization process. Supersatu- rated solutions of nontoxic materials with endothermic properties, and the electrogas-dynamic principle, are promising dispersal materials and techniques which require further de- velopment, as does research on the physics of fog. 183 PART VI — PRECIPITATION AND REGIONAL WEATHER PHENOMENA 4. TROPICAL WEATHER Monsoon Variations and Climate and Weather Forecasting The monsoon area extends from western Africa to northeastern Aus- tralia, being bounded to the north by the great mountain ranges of southern Asia. In the southern hemisphere it encompasses southeastern Africa and northern Australia but does not ex- tend beyond the equator over the central Indian Ocean. (See Figure VI-10) Its peculiarity, distinguishing the area from all others, is the marked difference in prevailing surface wind directions between winter and sum- mer. Winds blow predominantly from continent to sea in winter and from sea to continent in summer. Thus, in general, since moist air covers the continents in summer and dry air in winter, the summers are usually wet and the winters dry. Over the northern hemisphere this pattern is significantly distorted by the huge, elevated mass of Himalaya- Tibet which, through its thermo- mechanical effect on the atmospheric circulation, supports the vast perma- nent deserts east of 70° E. longitude, insures that India, Burma, and Thai- land experience arid winters and very wet summers, and keeps China rela- tively cloudy and moist throughout the year. Except for destructive winds asso- ciated with relatively rare tropical cyclones in the China Seas and Bay of Bengal, the attention of meteor- ologists in the monsoon area is focused on only one phenomenon — rain. Accurate long-range forecasts for agricultural planning, or short- range forecasts for irrigation or of floods would be invaluable to the economy of every country in the area. But rainfall variability on every time- Figure VI-10 — MONSOONAL AREAS 160° 140° 120° 100° 80° 60° 40° 20° W 0° E 20° 40° 60° 80° 100° 120° 140° 160° 180° 60° 40° 20° N 0° s 20° 40° 60° 60° 40° 20° N 0: s 20° 40° 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1^ 1 1 ■ — ■— . ^^^ -OX * 1 1 1 1 1 1 \ ) r7 r \ ** s •a 1 i i i i i 1 1 1 I 1 ? - 160° 140' 120° 100° 80° 60° 40° 20° W 0°E 20° 40° 60° 80° 100° 120° 140° 160° 180° The map delineates the regions of the world that are monsoonal — i.e., where the prevailing wind direction shifts at least 120 degrees between January and July. By sharpening the definition according to principles developed by Ramage, it is possible to define the true monsoon area as that included in the rectangle shown covering large parts of Asia and Africa. and space-scale — from inter-annual to diurnal and from intercontinental to mountain/valley — render clima- tology of limited use in providing the necessary planning information. Status of Tropical Meteorology Long-Range Forecasting — Most existing work was done in India and Indonesia before World War II. Mul- tiple-regression equations based on lag correlations were first used in the lQ20's to forecast seasonal rain- fall. Unfortunately, performance was disappointing — droughts and floods were never anticipated and predictor/ predictand correlations proved to be most unstable. Apart from a modest continuing search in India for new correlations, little effort is now being made. Unless the deterministic forecast methods to be tested in the Glo- bal Atmospheric Research Program (GARP) perform much better than even their most optimistic proponent expects, there is little chance of use- ful developments in forecasting sea- sonal rainfall extremes. Short-Range Forecasting — For the past fifty years the practice of tropical meteorology has been distorted (usu- ally unfavorably) by uncritical graft- ing of hypotheses and techniques developed in middle latitudes. As one scientist has observed: We have again and again ob- served very reputable and highly specialized meteorologists from higher latitudes who were deter- mined to solve the problems of tropical meteorology in a very short time by application of mod- ern scientific methods and use of new scientific resources such as 184 computerization. Then, after a few years, they find out that the thing doesn't quite work this way and the tropics cannot be approached by the methods used to solve prob- lems in higher latitudes. Training of Tropical Meteorolo- gists — Almost e'very professional me- teorologist in Burma and Thailand holds an advanced degree in meteor- ology from a foreign university, and yet their contributions to knowledge of even their own country's meteor- ology has been miniscule. In part, this is because many monsoon-area meteorologists have received inten- sive training in other countries, espe- cially in the United States and the United Kingdom, but almost never by teachers with any experience in, or appreciation of, monsoon meteor- ology. In this country, even the tropical meteorologists who instructed them, confidently and quite unjustifi- ably, would extrapolate their tropical oceanic experience to the continents. Numerical forecasting is the latest invader from the higher latitudes. Since some of the training received in other countries is at last beginning to seem relevant, everyone with access to a computer is trying out the models. Despite the fact that none of the models has demonstrated any weather forecasting skill over the Caribbean and around Hawaii, and despite the fact that problems of grid-mesh size are even more critical over the continents than over the oceans, resources which can ill be spared are being squandered on the latest fad — on the unsupported and unjustified assumption that numeri- cal forecast techniques have already significantly improved on subjective analysis and forecasting in the tropics. The machine churns out reams of charts — while professional meteor- ologist positions remain unfilled. In the monsoon area, the best aid to local forecasting is the cloud pic- ture from an Automatic Picture Transmission (APT) satellite. But the only way to use this information intelligently is through hard, subjec- tive evaluation, and this is so un- fashionable that a computer is often considered more desirable than an APT read-out station. A monsoon- area meteorologist, after intelligently and deliberately studying a detailed climatology and a sequence of care- fully analyzed synoptic and auxiliary charts (including APT pictures), can forecast consistently better than chance and significantly better than a numerical model. A statistical pre- diction should always be available to him. He should modify that predic- tion only when he discovers a sig- nificant change trend in the charts. When in doubt, stay with statistics. This may seem obvious, but such down-to-earth advice is rarely given during academic instruction. Training Facilities in the Tropics — If training in middle-latitude institu- tions is so inadequate, what about indigenous programs? In Asia, the Royal Observatory, Hong Kong, is a good but small cen- ter of research, emphasizing urban pollution and hydrological planning. Useful, practical, and theoretical studies are being pursued in the People's Republic of China. The In- stitute of Tropical Meteorology in Poona, India, is conducting good cli- matological studies but is also un- critically applying numerical forecast models developed in Washington, D.C., and Honolulu. The program in the University of the Philippines, launched with some fanfare three years ago, has apparently made no progress — an expensive faculty waits for enrollments but is ignored by meteorological services in the region. The Department of Geography in the National University, Taipei (Taiwan), has done good work, particularly on the effects of typhoons, while the Department of Oceanography in the University of Malaya (Kuala Lumpur) has made a promising beginning with useful climatological and synoptic studies. Apart from a small department of meteorology in the University of Nairobi, in Kenya (which has turned out at least one promising scientist), and, possibly, some activity at the University of Ibadan, in Nigeria, nothing much seems to be happening in Africa. Australia largely neglects monsoon meteorology except for a small in-house effort in the Regional Meteorological Center, Darwin. Over-all, the U.S. military interest in southeast Asia has contributed more to meteorological research and to improvement in meteorological training in the monsoon area over the past five years than any other factor. Research conferences spon- sored by defense agencies have pro- duced significantly more than just military benefits. One spin-off was the World Meteorological Organiza- tion training seminar conducted in December 1970, in Singapore. Summing up, short-range monsoon weather forecasting can be improved, but there is little chance of improve- ment stemming from the BOMEX ex- periment in the Atlantic (see Figure VI-11) or from continued training of monsoon-area meteorologists in insti- tutions with little understanding of, or interest in, the peculiar problems of monsoon weather. More can prob- ably be done by supporting the efforts in Taipei, Hong Kong, Kuala Lumpur, and Nairobi, particularly in the direc- tion of temporarily assigning out- side experts (perhaps on sabbatical leaves) to these places. The experts might even learn something from the experience! Scientific Communication — One other serious problem is that research into monsoon meteorology is pro- vincial. Investigators have seldom been aware that in other monsoon regions similar problems have been under study or even solved. Insuffi- cient scientific communication partly accounts for this. The only widely distributed journals are published in middle latitudes. Regional journals or research reports are often well dis- tributed beyond the monsoon area but poorly distributed within it. 185 PART VI — PRECIPITATION AND REGIONAL WEATHER PHENOMENA Figure VI— 1 1 — ARRAY FOR BARBADOS OCEANOGRAPHIC AND METEOROLOGICAL EXPERIMENT (BOMEX) 60,000 Ft • SAINT MARTIN ! N0RTH ■ ^ - RAINIER 500 W /j GILL 0 OCEANOGRAPHER ADVANCE II . -r ' v t ... Z/T" SO Ft • GUADAL0UPE i R0CKAWAY ^ _^ 0 BUOY TRITON LAUREL TRADE WINDS 1 Array will be oriented at right angles to Mean Trade Wind UNDAUNTED fT^ I X, / / ,*U. . ttW^BMr DISCOVERER r BARBADOS MT MITCHELL i~.. ™*aBiB^ tug KJ O • TRINIDAD • Land Based Station O Current Stations Thermistor Array Moorings The deployment of instrument platforms for BOMEX is shown in the diagram. This figure represents the consequence of designing a group of experiments of sufficient scope and precision to test hypotheses and obtain useful new data from an intermediate-scale system. The event is unique in human history. This experiment was participated in by the Departments of Commerce, Defense, Interior, State, and Transportation, the National Aeronautics and Space Administration, Atomic Energy Commission, the National Science Foundation, National Center for Atmospheric Research, and more than 10 universities. Basic Concepts The general character of the mon- soons and their inter-regional varia- tions reflect the juxtaposition of con- tinents and oceans and the presence or absence of upvvelling. However, without the great mechanical and thermal distortions produced by the Himalayas and the Tibetan Plateau, the vast northern-hemisphere deserts would be less desert-like, central China would be much drier and no colder in winter than India, while even over the Coral Sea winter cloud and rain would be uncommon. Within the monsoon area, annual variations are seldom spatially or temporally in phase. Even if these variations were understood and their phases successfully forecast, accurate day-to-day weather prediction would not necessarily be achieved, for the climatological cycles merely deter- mine necessary conditions for certain weather regimes; synoptic changes then control where and when the rain will fall, and how heavily, and whether winds will be destructive. Synoptic-Scale Changes — Al- though not new, a most important concept is that of wide-ranging, nearly simultaneous accelerations or decelerations within a major vertical circulation. Causes are elusive, al- though the changes generally appear to be triggered by prior changes in the heat-sink regions of the vertical circulation. This is a field of truly enormous potential for numerical modeling, on a time-scale between synoptic and seasonal, in which fluc- tuations in radiation and in air- surface energy exchange might pro- duce profound effects. The concept both explains previous difficulty in maintaining continuity of synoptic analysis and demands that notions of day-to-day weather changes be examined and probably modified. Even during winter, fronts seldom remain material boundaries for long and air-mass analysis con- fuses more often than not. That synoptic-scale disturbances often appear to develop and to weaken in response to changes in the major vertical circulations might ex- plain why many of the disturb- ances are quasi-stationary. In turn, synoptic-scale vertical motion deter- mines the character of convection and the efficiency with which energy is transported upward from the heat source. Synoptic-scale lifting, by spreading moisture deeply through the tropo- sphere, reduces the lapse rate and increases the heat content in mid- troposphere. Thus, though it dimin- ishes the intensity of small-scale convection and the frequency of thun- derstorms, it increases rainfall and upward heat transport. Conversely, synoptic-scale sinking, by drying the mid-troposphere, creates a heat mini- mum there, hinders upward transport of heat, and diminishes rainfall. How- ever, the increased lapse rate favors scattered, intense small-scale convec- tion and thunderstorms. 186 In the monsoon area, the character of the weather, on the scale of indi- vidual clouds, seems to be determined by changes occurring successively on the macro- and synoptic scales. Rains set in — not when cumulonimbus gradually merge but when a synoptic disturbance develops, perhaps in re- sponse to change in a major vertical circulation. Showers, too, are part of the synoptic cycle. Individually in- tense, but collectively less wet, they succeed or precede rains as general upward motion diminishes. When synoptic-scale lifting is com- bined with very efficient upper-tropo- spheric heat disposal, the lapse rate may be steep enough to support in- tense convection. Then, a vast, "con- tinuous" thunderstorm gives pro- longed torrential rain. Many times this takes place within the common upward branch of two major vertical circulations. Needed Scientific Activity Many tropical meteorologists have striven to make their work appear as quantitative and objective as possible. This commendable aim has led to im- portant climatological insights. How- ever, in synoptic studies their quanti- tative results have usually been belied by nature's quantities. A numerical model which determines that air is massively rising over the deserts of Arabia has limited validity no matter how quantitative and objective it might be. Energy-budget computa- tions in which precipitation and evaporation are residuals, or must be estimated, have also had their day. Forecasting and research should be inseparable. The very few monsoon- area weather services that enable their forecast meteorologists to spend at least one-third of their time on research have thereby greatly en- hanced staff morale and their scien- tific reputations, to say nothing of im- proved forecast accuracy. Combined forecast-research programs could well be successfully directed to solving problems and to increasing the num- ber of recognizable models of synop- tic circulations. The area covered by synoptic analy- ses should be sufficiently broad for the major vertical circulations to be monitored. Then interaction with synoptic disturbances and consequent effects on rainfall could be detected and possibly anticipated. Mesoscale gradients within synop- tic systems and their diurnal varia- tions might be better understood were studies to combine information from weather radars and weather satellites. Ceraunograms could help bridge the gap between meso- and synoptic scales. Aerial probing of con- tinuous thunderstorms would likely illuminate the shadowy picture we now have of energy transformations. We should view the future of mon- soon meteorology with optimistic dis- content. Regional progress in under- standing and forecasting weather has been disappointingly slow. However, attacks are being vigorously pressed on problems of concern to the entire monsoon area. What is needed is the hitra-nrca exchange of people and ideas. Tropical Meteorology, with Special Reference to Equatorial Dry Zones The outlook for meteorological ob- servations in the tropics, as now programmed, is excellent for many purposes and far superior to the past. Much can be done with existing and prospective observations in the way of field experimentation and synoptic- statistical modeling. Ambitious proj- ects like special or worldwide net- works or expeditions, however, should be undertaken only if the necessary data base is really assured. Further- more, meteorology, as a discipline, is still far too self-contained; special efforts are needed to promote inter- disciplinary research. Four problems are particularly in need of concentrated research in tropi- cal meteorology during the 1970's: Water Supply — This age-old prob- lem is becoming aggravated by popu- lation increases in tropical countries, as elsewhere. The need is to find ways to assure an adequate water supply over the middle and long term — i.e., on a seasonal or annual basis. Several avenues of scientific development could be promising: First, it has become more than ever urgent to improve weather-prediction methods. Second, experiments for in- creasing precipitation artificially need to be broadened to see whether (a) such increases are possible at all on tropical land areas; and (b) enough water can be produced by man to make a significant difference. While not directly a part of meteorology, desalination of sea water and diver- sion of large rivers (e.g., part of the Amazonas in northeast Brazil) also offer possibilities for enhancing tropi- cal water supplies. Tropical Storms — Again, the prob- lem has both predictive and modifica- tion aspects. Prediction beyond 12 to 24 hours remains a large problem in the areas affected by tropical storms and hurricanes. The German Atlantic Expedition of 1969 has again raised the question of whether tropical storms can be "modified" and, in- deed, whether or not it would be wise to do so. It should not be overlooked that tropical storms in many situa- tions and many areas bring great eco- nomic benefits, even though news re- 187 PART VI — PRECIPITATION AND REGIONAL WEATHER PHENOMENA leases usually cite only the damage they cause. Role of the Tropics in the General Circulation — The role of the tropics in hemispheric or global circulation is known to be important. The long- term (five days or more) prediction models now being developed require a tropical data input that is not vet adequate. In particular, studies are needed of (a) how constant the tropics are as a source of energy and momentum, and (b) the appropriate way to include in the models the energy infusions into the atmosphere from more or less point sources ■ — i.e., from small-area cumulonimbus cloud systems. In addition, ways must be found to represent surface interface processes, not only evapo- ration and sensible heat transport, but also momentum exchange, espe- cially on the equator itself. Hemispheric Interchange — Any interconnection between the extra- tropical regions of both hemispheres must take place via the tropics. From the spread of various tracers or aero- sols, over a scale of weeks or months, we know that an exchange of air does take place. An understanding of these exchanges is particularly rele- vant to problems of air pollution. Actual pollution problems in the tropics are not likely to become severe because of the unstable strati- fication, although tropical countries are, of course, exposed to sedimenta- tion or washout of pollutants by pre- cipitation. In the longer view, how- ever, the ability of the air to transport pollutants across the equator requires serious study of the air exchange — its mobility, the magnitude of the exchange, preferred paths, and the like, with a view to eventual control of such transports. Needed scientific activity under each of these major categories is dis- cussed in the sections that follow. Tropical Water Supply Some parts of the tropics are sub- ject to recurrent, severe droughts. Those of northeast Brazil, which have led to large out-migrations of popu- lation and great economic and politi- cal instability in all of Brazil, are an example. These droughts, superim- posed on an average rainfall that is itself marginal for a tropical economy, have lasted from two to as long as nine consecutive years. The longer droughts have occurred in the more recent part of the climatological rec- ords, suggesting a secular drying out — a most unfavorable circumstance. Many scientific questions remain before such tropical droughts can be understood, much less controlled. The droughts (as well as the inter- mittent heavy rainfall years) must be related somehow to the anomalies of the northern- and southern-hemi- sphere general circulations and pos- sibly to some oceanic temperature distributions that do not follow di- rectly from anomalous surface trade- wind speeds and directions, as well as to associated surface divergences or convergences. But the controls that govern these relationships are completely unknown at present. Lack of data over the tropics, the southern oceans, and even the North Atlantic at lower latitudes has prevented any definitive study. Little adequate use has been made of such information as is available — surface temperature, pressure, and precipitation anomalies over wide areas, as well as recent findings on wind anomalies over the equatorial Atlantic. Data Base — New data are accumu- lating very fast for all parts of the tropics, eliminating the old excuse that lack of observations prevents progress. Data have been accumu- lating from the rapidly growing num- ber of commercial flights over tropi- cal areas. Programmed new satellite data are adding even more rapidly to the pile. An energetic attack on the discovery of the controls of equatorial dry zones and variable rainy seasons should be possible in the 1970's as a result of these new data. Once the controls are known, it will be possible to see whether prediction of the con- trol functions can be achieved with synoptic-statistical modeling tech- niques, although direct deterministic prediction does not appear in the picture for the foreseeable future. Cloud Modification — The ques- tion of cloud-modification potential in the tropics remains unresolved. Nonprecipitating cumulus congestus may be a preferred cloud form over many semi-arid tropical areas. But past efforts to study the possibilities of modifying such clouds have been rather sporadic. Early interest in Aus- tralia has lagged. A few serious cu- mulonimbus studies have been made in the Caribbean, but these relate to the atmosphere over open sea; since surface heat sources are much stronger over land, these oceanic ex- periments cannot be applied directly to the tropics, although they may be useful indirectly if they are successful in making cumulonimbus grow. Quite apart from modification ex- periments, it would be of value merely to learn the cloud composition at different locations in order to assess what might be termed the "stimulation potential." Even in this respect, knowledge has remained de- ficient. There exists on this subject a great need not only for scientists but also for adequate instrumentation (notably radar) and good technicians. Good radar technicians actually avail- able for meteorology are rare, and in tropical countries they tend to be either nonexistent or insufficiently skilled. The World Meteorological Organization has a large technician- training program, which merits sup- port. Tropical Storms Tropical storms are notoriously variable in frequency from year to year and region to region. (See Figure VI-12) Sometimes the connection with the general circulation is obvious, but not always. The role of hurricanes in the general circulation is not yet fully determined, and general-circulation research, with a focus on general cir- 188 Figure VI-12 — FREQUENCY OF TROPICAL CYCLONES North Atlantic Ocean 73 North Pacific — off west coast of Mexico _. 57 North Pacific Ocean, west of 170°E ..... . 211 North Indian Ocean, Bay of Bengal 60 North Indian Ocean, Arabian Sea 15 South Indian Ocean, west of 90°E 61 South Indian Ocean, northwestern Australia 9 The table shows the frequency of tropical storms per 10 years. The numbers are only estimates of the number of tropical cyclones to be expected, since, until recently, there have been no reliable statistics except for the Atlantic, where ship traffic has been heavy and island stations numerous for many years. Surveillance by satellites will provide worldwide coverage of tropical cyclones. dilations favorable or unfavorable to tropical storms, is definitely needed. Clearly, such storms are not mere nuisances. A single hurricane can re- place the function of the equatorial trough zone in the Atlantic for verti- cal transport of heat and moisture and their transmission to higher lati- tudes. Altogether, the true value of such storms — when, where, and under what circumstances needs to be stressed and measured. Coastal dam- age and associated flooding from hur- ricanes in areas such as southeastern United States usually receive the widest publicity. It is forgotten that, as these storms move slowly inland and turn into unspectacular inland rains, they have on occasion saved the cotton crop and even relieved water shortages of cities such as At- lanta. Lowered water tables over southern Florida and other areas, with their danger of salt-water intrusion into the water supplies of cities like Miami, can also be counteracted by hurricane precipitation. In terms of dollars, then, hurricanes can often bring benefits that are comparable to the damage they cause. Impact of the Tropics on World Weather Long-Period Trends — As the en- ergy and momentum source for the general circulation, the tropics are most likely to have an important im- pact over long time-scales (from months to years). The excess of energy acquired and held by the tropical oceans may undergo slow variations of possibly great impor- tance for long-period circulation anomalies. Bjerknes, for example, has speculated on the equatorial Pa- cific and its influence over large areas beyond the tropics. Expanded observational networks at sea and, again, satellite data now appear sufficient for empirical re- searches to begin on such aspects of general circulation. Theoretical modeling would also be useful to in- dicate how much variation in the tropics is needed to produce an even- tual circulation upheaval elsewhere. From models that have been run so far, it appears that the heat accumu- lations or deficits need not be very large. The intensity of the mean merid- ional circulation is also a matter for serious study. Data are marginally sufficient to calculate this circulation on a monthly, if not weekly, basis. Variations in the cell have hardly been considered at all; yet they would profoundly affect, among other things, the energy and momentum bal- ance picture, subtropical jet streams, stress in higher latitudes on the ground, and relations to the intensity of the Siberian winter high. Short-Period Fluctuations — Vari- able exchanges with the tropics may be responsible for the "index cycle" of the general circulation in the west- erlies on a two- or three-week scale. Prediction experiments now planned in connection with the Global At- mospheric Research Program (GARP) may or may not lead to an under- standing of such influences. Sepa- rate studies — using diagnostic data from the National Maritime Commis- sion and other hemisphere analyses and data storages — would also be of considerable value. Such studies could also investigate whether the exchanges are forced from higher latitudes, and in this way learn more about the mechanisms for the vari- ability of the atmospheric machine. For prediction equations, much em- phasis has been given to parameter- ization of cumulonimbus convection, since a few thousand cumulonimbus cover roughly 0.1 percent of the tropics at any one time. Much re- search on this subject is under way, although some dispute remains as to the form the research should take. GARP takes the view that a master tropical experiment must be con- ducted for final clarification. While a series of smaller projects might be inadequate for the problems to be solved, the master experiment may not succeed either, since experimental difficulty increases nonlinearly with the size of an experiment. Further- more, there is a deplorable tendency to ignore the results of past expedi- tions in writing the prospectus for new ones; in present planning, for example, such large undertakings as the German Atlantic Expedition and its results have been generally over- looked. Emphasis should not be placed ex- clusively on oceanic observations. Obviously, the oceans hold much of the key to world weather; but pre- dictive models should eventually be geared mostly for continental areas, 189 PART VI — PRECIPITATION AND REGIONAL WEATHER PHENOMENA where predictions are most needed. Continental models will necessarily differ from oceanic ones. Continents do not have surface-heat storage in the sense of the oceans, and frictional stresses as well as nuclei spectra for condensation and freezing are differ- ent. Oceanic research could thus use- fully be supplemented by research over land. Collaboration with exist- ing continental experiments, such as that of northeastern Brazil, could bring large technical rewards. Interhemispheric Communication In many ways, it appears that the center of the equatorial convergence zone separates the hemispheres mete- orologically as well as physically. Each has a self-contained energy and momentum budget, for example. If this picture were true for all time- scales, then the two hemispheres could be treated as independent of each other for all practical meteoro- logical purposes. No one really believes this, how- ever, although there is much doubt as to the time-scale on which inter- hemispheric mechanisms are impor- tant. Preliminary calculations based on data dating from the International Geophysical Year (IGY), in the 1050's, have not revealed any impor- tant connections; but then, the tropi- cal network of IGY was so deficient that it is impossible to treat these data as definitive. Here we see the danger of inadequate observational efforts. Better data are likely to emerge from superpressure balloons, World Weather Watch stations and satellites, and the buoys and other in- stallations of the GARP network. If these networks and data sources are kept up and expanded, a good start could be made during the 1^70's on resolving the questions relevant to the importance of interhemispheric communication for long-range weather changes. Irrespective of long-period weather control, an understanding of mass ex- changes across the equator is impor- tant to the prospects for worldwide pollution control. We know that mass exchanges across the equator occur, but we need to determine whether the drift of pollutants across the equator occurs with indifferent distribution in troposphere and stratosphere. If that is the case, nothing can be done to protect one hemisphere from the other, but there may be point-, or small-area, injections in preferred and stationary locations. If that is so, trajectory calculations toward these areas and measurements along them would at least permit warning of im- pending transports of particular pol- lutants at a high level. 190 5. DUST African Dust and its Transport into the Western Hemisphere Meteorologists have recently dis- covered that enormous quantities of dust are raised over arid and semi- arid regions of North Africa and in- jected into the trade winds over the North Atlantic. Outbreaks of dust from the Sahara take about one week to reach the Caribbean. The amounts of dust are highly variable in space and time, both from day to day and season to season, but the period of maximum dust transport across the Atlantic (June to early September) coincides with the Atlantic hurricane season. Dust outbreaks from Africa often appear on meteorological satel- lite photographs as a semi-transpar- ent or transparent whiteness that re- sembles thin cirrus clouds. (See Figure VI-13) In such outbreaks, surface visibility can be moderately reduced as far west as the Caribbean. African dust outbreaks and the hurricanes that also have their origin over Africa may be interrelated in some ways. While it is highly un- likely that African dust can cause wind disturbances to form into hur- ricanes or hurricanes to dissipate, there is enough observational and theoretical evidence to suggest that the two phenomena might affect each other indirectly or directly in a sec- ondary role. The dust's ability to directly influence hurricanes lies in its ability to affect the thermodynamics of cloud growth through its role as an ice or condensation nucleator. More indirectly, the dust can affect the energy balance of the tropics by its ability to block incoming radiation from the sun or outgoing infrared radiation from the earth's surface. Dust can also serve as a tracer of atmospheric air motion. There is some evidence that an enhanced dust transport accompanies the movement of wind disturbances off the west coast of Africa. The dust content of the air can be modified in the disturb- Figure VI-13 — DUST OVER THE TROPICAL ATLANTIC This satellite photograph was taken by the ATS-3 satellite on the afternoon of August 11, 1970. It shows a great cloud of African dust between 30° and 60° W. longitude just north of the Tropic of Cancer. ance either by being washed out in rain or by being evacuated to very high altitudes in the updrafts that accompany giant cumulus clouds. When it is transported to levels well above the 3- to 4-kilometer depth over which it is normally found, the dust can more readily affect the en- ergy balance and particulate concen- trations in other parts of the globe. Characteristics of Dust Transport Since 1965, quantitative measure- ments of windborne dust transport have been made on a year-round basis at a tower on the island of Bar- bados, in the lower Antilles. (Re- cently, two more such stations have been set up to measure dust in Ber- muda and Miami.) These measure- ments, made by scientists from the University of Miami, show that the airborne dust loading is highly vari- able from day to day, season to sea- son, and even year to year. Like hurricanes, the primary activity is in summer when the dust transport averages 10 to 50 times more than in winter, with the daily amounts vary- ing from about 1 to 40 micrograms per cubic meter. Variability — Air-trajectory analy- sis shows that the summer dust orig- inates over arid to semi-arid regions in the northwestern corner of the African continent, and is swept south- ward and toward the Caribbean by the strong northeasterly winds that exist in that sector during summer. The width of the dust-carrying air- stream is only 300 to 500 miles wide as it leaves the coast of Africa, and the depth of the dust layer is about 12,000 feet as determined by the depth of mixing over Africa. Al- though this flow of dust is more or 191 PART VI — PRECIPITATION AND REGIONAL WEATHER PHENOMENA less continuous, the variations in dust content of the air are often quite abrupt. Locally, the variation in dustiness can be due simply to a shift in the dust-laden airstream. In many in- stances, large increases in dust load- ing in the Caribbean can be tied to specific outbreaks of dust-storm ac- tivity over parts of North Africa. At other times, the increases in dust load- ing of the trade winds are attribut- able to the venting of the normally dusty air over the African continent by a favorable wind regime which brings air from deep in the interior of the Sahara into the Atlantic trade winds. In many cases, however, it is impossible to assign a cause to the dust outbreak or even to detect the variation of dust loading downwind from Africa without direct measure- ments. Visibility — The presence of Afri- can dust in the Caribbean can be seen as thick haze, with visibility reduced from 20 to 30 miles, in the case of no haze, to only between 6 and 15 miles. In exceptionally hazy areas of the Caribbean, the horizon resembles that on a dry day of the American Midwest or on a muggy day in a large city of the Northeast. Indeed, the dust loadings over the Caribbean are probably comparable to or greater than those that would be found over much of continental United States. Source — There is an abrupt change in the general source region of the dust between winter and sum- mer. After October and until May (with some rare deviations), the dust is ash-gray to black and is thought to originate over the sub-Sahara from the Cameroons through central Ni- geria and the Ivory Coast. In the summer, however, the flow of dust is primed by the strong northeasterly winds associated with the intense pressure gradient that exists between the low pressure of the central Sahara and the relatively high pres- sure along the western coast. Then, the dust is a reddish-brown color with a tinge of yellow. Particle Size — A surprising as- pect of the size spectra of the dust reaching the Caribbean is the rela- tively large fraction of the dust (5 to 20 percent) with particle sizes in ex- cess of 10 microns. In general, the higher the dust loading the higher is the fraction of dust in the larger size ranges. According to Stokes, settling- velocity particles in excess of 10 microns would settle out of the air before reaching the Caribbean unless they were raised to heights well in excess of 20,000 feet. Since the visible dust top is rather distinct at about 10,000-15,000 feet over the Carib- bean, and is directly related to the top of the turbulent mixing layer over the Sahara, which is at about the same altitude, one can assume that virtually all the dust falls from below 10,000-15,000 feet. Although a sub- stantial fraction of the dust un- doubtedly settles out before reaching the Caribbean, a certain fraction of all size ranges is prevented from being lost by the recycling of air (turbulent mixing) in the dust layer over Africa and in the trade winds. Vertical Distribution — Recent ob- servations of the vertical distribution of the dust show that the dust con- centration in the air downwind from the Sahara is greatest in the layer between the dust top and the top of the cumulus layer (say, 4,000 to 8,000 feet). In the lower layers, the trade- wind air may be air of non-Saharan (or partially Saharan) origin that flows southward to undercut the original dust airstream, being thereby enriched by mixing and by fallout from above. Possible Relation of African Dust to Tropical Disturbances A great deal of indirect theoretical and observational evidence exists to suggest that African dust may play some secondary role in the growth or suppression of tropical disturb- ances and the entire energetics of the tropical atmosphere. Conversely, some observations indicate that Afri- can disturbances have some effect on the movement of dust into the Carib- bean and that the behavior of the dust is at least superficially affected by the presence of these wave per- turbations. Dust as a Nucleator — It is well known that the size spectra and num- bers of condensation nuclei have a profound effect on the population of water droplets in clouds and the ability of the cloud to precipitate. These condensation nuclei are derived from various types of atmospheric aerosols — salt particles, dust, pol- lution, and the like. Much research has been done both in the laboratory and in the field, to determine the nucleating properties of various sub- stances and their relative importance in cloud growth. Similarly, the formation of ice crys- tals from supercooled water in clouds depends on the presence of foreign freezing nuclei and on the distribu- tion of existing ice crystals. Almost any substance will nucleate ice at some temperature, but only a rela- tively few types of substances are efficient in this capacity — i.e., are able to promote freezing at tempera- tures warmer than about —20° cen- tigrade. The best-known and most efficient type of nuclei air crystals is silver iodide, which has been used in cloud-seeding experiments. But silver iodide is not found naturally in the air in significant quantities. The most efficient natural ice nuclei are the clay minerals — notably kaolinite, il- lite, and montmorillite. These three minerals are abundant in the soils of North Africa and have been found to be a prominent constituent in the African dust. Since the haze top is near the freezing level, the dust could only be effective in freezing if it were entrained into large cumulus which protrude to heights well above the haze top. Until very recently the Atlantic trade winds were thought of in terms 192 of a maritime environment in which aerosol distribution was made up of sea-salt particles which provide the clouds with giant hygroscopic nuclei for condensation and with possible sites for freezing. The Barbados measurements, however, show that the bulk dust density in the air is greater than the expected concen- tration of sea-salt particles, even near the surface. Additional measure- ments made recently from aircraft near Barbados show that the ice nuclei were as high as 10; to 104 per cubic meter in visibly dusty areas, values that are comparable to those found over the continents. At other times, the ice-nuclei concentrations were found to be negligible in areas of dense haze. These measurements suggest that the ice nuclei are deacti- vated under certain conditions, pos- sibly by surface contamination with Aitken nuclei, water droplets, or some form of pollution. Such ambiguities in the physics of ice nuclei and the lack of aerosol measurements in the tropics preclude even an educated guess as to the effect of African dust on the growth of disturbances. At present, argu- ments can be made for either sup- pression or enhancement of cloud growth given an abundant supply of aerosols. Much more evidence is required to form a quantitative picture of how much dust is entering the convective clouds associated with the disturb- ances and what the distributions are of ice and condensation nuclei in the cloud environment and the popula- tion of ice crystals and water drops in the clouds. Additional aerosol and dust measurements need to be made along the African coast and by air- craft flying in the vicinity of African disturbances. A more detailed knowl- edge of the vertical distribution of dust and other aerosols should be sought in these flights. If efforts are going to be made to seed disturb- ances, it would be important to know exactly what the background seeding capacity of the environment is during a period of exceptionally high dust content in order to estimate the seed- ability of the clouds in these hazy areas. Aerosol measurements of any sort made over Africa itself would be most useful. Dust as a Tracer of Air Motion — Besides being an active participant in the condensation and energetics of cumulus clouds, the dust is useful as a tracer of air motions in the trade winds, thereby leading to an under- standing- of the dynamics of air mo- tion at low altitudes. Some tentative evidence exists showing that the dust transport off the African coast is much enhanced by the passage of an African disturbance south of the dust-producing area. Intensely hazy areas, visible on satellite photos, were concentrated immediately to the rear (east) of an African disturbance on two or three occasions in the sum- mer of 1969. In these particular dust outbreaks, the leading edge of the dust mass remained close to the axis of the easterly wave disturbance as it crossed the ocean and passed the island of Barbados. Statistics for the past three years show that the pas- sage of African disturbances by Barbados is accompanied by a sig- nificant diminution in dust loading just prior to its arrival and a marked increase, leading to maximum dust loading, immediately after passage of the wave axis by Barbados. It is not clear whether the disturbance actu- ally prevents the dust from passing the wave. Examination of radiosonde data shows that the temperature, stability, and water-vapor content of the air is singularly different in the dusty area. In general, air of high dust content is accompanied by a minimum of cloudiness. This is probably due to a more rapid subsidence of the strong northeasterly trades that are espe- cially susceptible to the raising of dust over the continent and to the increased stability at low levels found in the dusty air, rather than to an in- teraction of the dust with the clouds. Chemical, mineralogical, and analysis of the dust is another pos- sible method for determining the origin, composition, and seeding pos- sibilities of the dust. This has been done on a number of selected occa- sions using the Barbados dust sam- ples. The results so far are inconclu- sive, but they do show significant variations in quartz, calcite, iron, and other substances between winter and summer dust. In addition, the lead and zinc content of the summer dust is anomalously high, especially in comparison to the very low amounts of these elements in the winter dust. These two elements owe their abun- dance to industrial contamination, notably fossil fuels. Therefore, the air that carried the dust from the northwestern corner of the Sahara was likely to have been over indus- trial Europe immediately before its arrival over Africa; conversely, the winter dust is carried in an airstream of long-standing duration in the tropics. Measurement Techniques and Their Implications Radon-222 — Some indirect meas- urements of dust content can be made using radon-222 as a tracer of Sa- haran dust. Radon-222 is liberated from soils in large quantities and is mixed throughout the lower layers of the atmosphere in much the same way as water vapor and dust are mixed from their sources at the earth's surface. Unlike dust, how- ever, radon gas is not washed out by rain. This property (insolubility) can provide a means of studying the washout of dust and the later move- ment of Saharan air after it has passed through a cycle of cumulus convection. Thus, radon-222 measured in the high troposphere may be useful in tracing the outflow of dusty air from the tops of cumulonimbus and can lead to a substantiation of the theory that the high concentrations of ice nuclei and dust particles sometimes 193 PART VI — PRECIPITATION AND REGIONAL WEATHER PHENOMENA found in the upper atmosphere are of terrestrial origin. Radon measure- ments in the southern hemisphere south of the North Atlantic trade winds can provide valuable informa- tion on cross-equatorial flow and the flow of air across the Intertropic Convergence Zone. In one aircraft expedition made by a U.S. research team flying between Miami and Dakar, a high correlation was found between haze and radon activity. This relationship between dust and radon activity was substan- tiated in further aircraft flights made near Barbados in I^b® and by some measurements made on board the US5 Discoverer the same year. Radon was also measured south of the equa- tor on the flight. More such flights and expeditions are needed to expand our fragmented knowledge of dust transport. LIDAR — Another indirect method for estimating the vertical distribu- tion of dust is with LIDAR, which measures the back-scatter from a laser beam. However, back-scatter measurements are highly dependent on particle size and are extremely difficult to interpret in terms of dust distribution without supporting data to accompany them. Turbidity Measurement -- More useful than LIDAR in the study of dust is the measurement of turbidity from photometric measurements of skylight distribution and spectral at- tenuation of solar radiation. These turbidity measurements can also be compared with atmospheric back-scat- ter and albedo as determined from satellites. Atmospheric dust over the tropical Atlantic can have an im- portant effect on the energy balance of the tropics and, consequently, on the global circulation. Since the at- mospheric turbiditv is a function of the aerosol content of the air, the total incoming and outgoing radia- tion and the changes in absorptivity and emissivity on the vertical can af- fect the heating and the convective instability of the trade winds. There is some evidence that the growing pollution over the earth during the past few decades has resulted in an increase in atmospheric turbidity and a slight decline in worldwide tem- perature. An increase in turbidity at low latitudes can effect a decrease in worldwide temperature and a slowing down of the general circulation of the whole earth. At present there is some question as to the cause of the turbidity increase over the years. It may actually be due to natural causes such as volcanic eruptions or changes in dust content of the air rather than to industrial pollution. Since sig- nificant changes in dust loading from year to year do occur in the Atlantic trade winds (the amount of dust reaching Barbados in the summer of 1969 was double that in the previous four years of record), it would there- fore be useful to measure turbidity in the Atlantic trade-wind area on a yearly basis in order to determine the natural fluctuation in the components of the radiation balance there. African dust may thus influence tropical storm development indirectly, by means of its capacity to alter the long-term thermodynamics of the tropical environment. 194 PART VII WATER RESOURCES, FORESTRY, AND AGRICULTURE 1. WATER RESOURCES Estimating Future Water Supply and Usage Most estimates of water supply and usage have been couched in terms of average annual water supply and projected usage at some future date. For small areas within the scope of a single project or a system of proj- ects, water supply is sometimes stated as the mean flow available during the most critical dry period in the record. Such assessments have the virtue of simplicity and are reason- ably well understood by the layman. At the national level, a statement of mean water supply and mean usage is probably entirely adequate because water-supply problems are never solved at that level. At the regional and local level, however, use of the mean supply available and a projected future usage deprives the planner of the opportunity for strategic evaluation of alternatives. The planner is concerned with sup- plying water for a specific period of years into the future. It is virtually certain that the actual streamflows during this future period will not duplicate those of the historic past and that water usage at the end of the period will not precisely equal the forecast. Faced with such uncertainty, the planner would be wise to treat both variables in terms of probability. Only through a probabilistic treat- ment can he evaluate the risk of expanding water-supply facilities too fast, with consequent excessive costs and risk of losing future technologi- cal advantages, or of developing a system so slowly as to threaten a serious water shortage at some future date. Estimates of Water Supply The data base for estimates of water supply consist of approxi- mately 10,000 gauging stations oper- ated mostly by the U.S. Geological Survey; in addition, many thousands of wells provide information on groundwater levels. There may be specific local deficiencies in this data base, but on the whole it must be judged reasonably adequate. It is fortunate that this base exists, be- cause only time can remedy deficien- cies — from 30 to 100 years of record are required to describe statistically the characteristics of water supply. Qualifying Factors — Interpretation of existing data on streamflow and groundwater is complicated by the fact that few stations record virgin conditions. Regulation by reservoirs, diversion from streams, pumpage from groundwater, alteration of stream channels, vegetation-manage- ment practices, urbanization, and many other factors render available data series inhomogeneous over time. In some cases, the effect of man's activity is rather accurately known and appropriate corrections can be made. In most instances, however, only the sign of the change can be stated with accuracy. Synthetic Streamflow Records — The last decade has seen the devel- opment of hydrologic simulation us- ing both digital and analogue com- puters. Simulation is capable of transforming precipitation data into synthetic streamflow records. Simu- lation brings many thousands of precipitation stations operated by the National Weather Service into the data base and makes it possible to make streamflow estimates at sites where no gauging station exists. Be- cause precipitation records are gen- erally longer than streamflow records, simulation permits the extension of flow records at currently gauged sites. Similar development has taken place with respect to simulation of groundwater basins primarily through the use of analogue models. Al- though these models cannot perfectly reproduce historic streamflow or groundwater basin performance be- cause of errors in the data inputs and deficiencies in the models them- selves, errors in model outputs are generally random and pose no serious problem in probabilistic estimates of water supply. Simulation models also permit adjustment of observed flows or groundwater levels to virgin or natural conditions. It may be con- cluded, therefore, that we are now able to combine observed and syn- thesized data into a data base cover- ing a sufficient period of time to de- fine the mean and variance of water supplies with reasonable accuracy. Problems of Data Projection — The historic data base, observed or simu- lated, does not fully satisfy the need for projections of future water sup- ply, however. The water-supply planner is concerned with possible events over a specific period ranging from 20 to 100 years in the future. He is particularly concerned with the sequences of annual flows, be- cause a series of consecutive dry years will impose a much greater burden on his reservoir (surface or subsurface) than the same number of dry years dispersed over his plan- ning horizon. To meet this problem, the field of stochastic hydrology has developed during the 1960's. Stochastic Hydrology — In stochas- tic hydrology, generating functions derived from the estimated statistical characteristics of the historic record are used in conjunction with random numbers to generate many possible flow sequences. Thus, a thousand years of stochastic streamflow can be broken into ten 100-year periods, from which the planner can estimate 197 PART VII — WATER RESOURCES, FORESTRY, AND AGRICULTURE the probability that a proposed reser- voir will be adequate against any of these ten alternative futures. Streamflow is inherently more vari- able than precipitation and it is fair to assume that we know the statisti- cal parameters of precipitation with greater accuracy than those for streamflow. It follows that the stochastic generation of precipitation data should be a more certain process than stochastic generation of stream- flow data. Stochastically generated precipitation data can be converted to streamflow by deterministic simu- lation models, although the process would be substantially more expen- sive than direct stochastic generation of flow data, since deterministic simulation is inherently more com- plex and time-consuming. Preliminary work on stochastic generation of rainfall has recently begun, but fur- ther research should be encouraged. The Relevance of Climate — In addition to the stochastic properties of future streamflow, a number of other issues arise before the planner can be content with his projections of future water supply. The first of these is the question of long-term climatic trends. An abundance of data demonstrates the existence of such trends in terms of geologic time and in terms of periods as short as a few hundred years. However, no sound basis exists for predicting the existence of a trend and its conse- quences over the next century. Cli- matic trends could alter the water- supply outlook in arid and semi-arid regions, since the hydrologic balance is sensitive to small changes in pre- cipitation input or evapotranspiration outgo. Techniques that could iden- tify causes and project trends, even in an approximate fashion, would be extremely valuable to the water- resource planner. The Relevance of Human Activ- ity — In addition to natural climatic trends, future water supplies may be affected by man-induced changes, both intentional and inadvertent. Intentional changes include those brought about by land-management practices, vegetation management, de- salinating of brackish or saline wa- ters, or effective reclamation of waste water. The question that confronts the planner is "Will any of these become practically useful and if so when?" The issue is the evaluation of probable rates of technological advance. It will be seen that similar questions arise in the discussion of water usage. Inadvertent changes in water sup- ply may be brought about by urban- ization, which increases surface runoff and decreases infiltration to ground- water. If one can make reasonable projections of future urban growth, deterministic hydrologic models can project the alterations in streamflow and accretion to groundwater. More subtle are the effects of air pollution, urbanization, and changes in land use and vegetative cover as they may affect climate. These possibilities underline the importance of research on climatic change. Estimates of Water Use The problem of predicting future water use is far more complex than that of predicting water supply, if only because of the much larger number of components that must enter the forecast. It is convenient to divide the discussion of water use into the requirements for the several purposes to which water is most commonly applied. Before each of these purposes is discussed, how- ever, two general topics should be noted. General Considerations — First, the distinction between diversion and consumption should be underlined. For many purposes, large quantities of water are diverted for use but only a small fraction of the diverted water is consumed; the rest is returned to the environment — sometimes de- graded in quality. (See Figure VII-1) An outstanding example is the use of water for cooling in industry and power generation, which actually con- sumes very little water; most of the water used is returned to a stream or to the groundwater substantially warmer than when originally diverted. Because of the re-use aspects, dis- cussion of diversion requirements is confusing. Here we will consider only consumptive use. Consumptive use is defined as that portion of the water which is evaporated or com- bined in the product so that it is no longer available for re-use in the original source system. A second topic which deserves consideration on a general basis is that of population forecasting. For nearly all water uses, estimates of population and its geographic dis- tribution are fundamental. If prob- ability estimates of future water use are to be derived, they must begin with estimates of probable future population. Research has been done on the variance of population esti- mates as indicated by statistical eval- uation of historic predictions. A more fundamental study might ex- plore the uncertainties in each of the factors involved in population forecasting. The most difficult problem is the forecasting of local population by county or city units. Factors that do not enter national population fore- casting are involved in predictions of the distribution of population. Not the least of the factors that may affect future distributions is govern- ment policy concerning desirable population distribution. Some re- search on the optimal size of popu- lation concentrations may be useful. Is there a city size at which the unit cost of infrastructure is mini- mized? What are the advantages of population dispersal against increased growth of major metropolitan cen- ters? Domestic Water Use — The ques- tion of domestic water requirements depends largely on two issues. One 198 Figure VI 1—1 — DISPOSITION OF WATER DIVERTED FOR IRRIGATION Evapotranspiration from Crop Area Evaporation before returning Water Resource Pool The diagram shows schematically what becomes of water diverted for irrigation purposes in the U.S. The width of the stream represents the relative quantity of water moving in that path. Water is consumed by evaporation from various sources and evapotranspiration from irrigated areas. This reduces the water supply available for sequential uses. The non-consumptive paths such as seepage, runoff, and perco- lation return water to the resource pool, leaving it available for subsequent uses. This return water may improve or degrade the water quality depending on the initial quality of the water, the uses to which it has been put, and the particular character- istics desired by the sequential users. is the technology of water use. Plan- ners have generally assumed a slow increase in per capita water require- ments. It should not, however, be exceptionally difficult to redesign conventional plumbing fixtures and water-using appliances so that water- use rates are reduced without sacrific- ing the amenities of present users. The second factor that might sig- nificantly affect domestic consump- tion would be changes in life styles. A shift from dispersed single-family residences to multi-family residences would be the most significant change. Savings in water would be achieved through reduction in lawn and garden water requirements. Changes of this kind are probably closely related to technology through construction costs, transportation techniques, dis- position of leisure time, and public policy with respect to taxation. Sub- jects for research on the impact of technology on society in this area are abundant. Industrial Water Use — The aver- age values of industrial water use per unit of product produced are ex- tremely large in many industries. There are, however, many opportu- nities for reducing water use by re- cycling, recovery of by-products, and other techniques. Estimates of future industrial use are dependent on esti- mates of future industrial production and the extent to which water- conservation techniques are applied. Water in Agriculture — The largest water-using sector in the United States today is irrigated agriculture. In states like California, over 90 percent of the water use is for irriga- tion. Future agricultural water re- quirements are therefore extraordi- narily important. Unfortunately, they are difficult to assess. What are the future needs for food and fiber production? How much food and fiber will the United States produce for export? How much can food and fiber production in the humid eastern states be expanded? How can water- use efficiency in agriculture be im- proved? What is the possibility of breeding crop types requiring less water or capable of using brackish water instead of fresh water? To what extent will it be possible to raise crops in arid regions in controlled environment chambers? Will exten- sive, low-cost greenhouses in which water use can be carefully controlled become technically feasible? These questions all involve issues of tech- nical feasibility, extent to which efficiency of production can be im- proved, and time-rate at which these developments can be expected. Energy Production — The consump- tive water requirements for the pro- duction of electric energy are rela- tively small. A hydroelectric power plant actually consumes only small amounts of water evaporated from the reservoir surface. A thermal plant consumes the water evaporated in cooling the condensers. If predictions that power demands will continue to double every decade (thousand-fold increase in 100 years) prove accurate, however, the current relatively small use will grow rapidly into a major source of water consumption. Again, the projection of water re- quirements for power production raises mainly technological issues. What are the prospects for new types of thermal power producers for which cooling- water requirements are less? Are there possibilities of cooling methods that are less demanding on the water resource? Use of heated condenser water for irrigation shows promise of minimizing the "thermal pollution" of streams and improving the efficiency of irrigation. Not all thermal power plants can be situated close to potential irrigated areas, however. What other uses of waste 199 PART VII — WATER RESOURCES, FORESTRY, AND AGRICULTURE heat may be feasible? Is it conceiv- able that per capita power require- ments may be reduced by reducing power requirements in the home and industry? Can climate control be achieved? Will future urban centers require less energy and water for airconditioning? Navigation — Navigation is not an extremely heavy user. Evaporation losses from reservoirs from which water is released to maintain navi- gable depths downstream constitute the primary consumptive use. The quantity is probably so small that it deserves little consideration as com- pared with other demands on our water resource. However, it is appro- priate to ask what future transporta- tion technology may be expected. Will relatively slow, bulk transport by water continue to be a favored procedure? Will high-speed surface or air transport encroach on the market for bulk transport to the point where future expansion of navi- gation facilities may stop? Recreation — Like navigation, rec- reation is not presently a heavy con- sumer of water. Primary water use by recreation is evaporation from reservoirs constructed solely for wa- ter recreation or from an increased water surface area in reservoirs be- cause of projected recreation. It is unlikely that reservoirs will be built solely for recreational purposes in water-short areas. Recreation does not appear to be a factor of great uncertainty with respect to future water use. However, it may be ap- propriate to mention here the pos- sibility of evaporation suppression from water surfaces by the use of film-forming chemicals or covers. If successful techniques for evapora- tion suppression could be achieved, requirements for many of the uses discussed above could be reduced. Fish and Wildlife — It is currently accepted that the maintenance of fish and wildlife requires that a con- tinued flow be maintained. A sub- stantial part of this flow is eventually discharged into the oceans where it can no longer be used. Water re- quirements for this purpose are surely not well known. The mech- anisms by which a reduction in dis- charge into estuaries may affect marine life need to be established. This need derives from two com- peting aspects. We need to know how much water must be permitted to flow to the oceans in order to maintain fisheries for both economic and sports purposes, and the extent to which this fresh-water flow in- fluences other estuarine and oceanic resources. We also need to know the consequences of excessive flood flows through estuaries. Are such flows beneficial or detrimental? In addition to the consequences for fish- eries and wildlife, what are the effects of regulating streamflows to the ocean on sediment deposits in es- tuaries and harbors and on nourish- ment of beaches? In summary, probability estimates of water supply are limited only by hydrologic understanding, and solu- tions appear to be close at hand. Projections of water usage are heavily dependent on projections of new technology. Little effort has been devoted to this latter problem and, therefore, current projections of use are quite uncertain. Water Movement and Storage in Plants and Soils Since only five feet of soil can generally store fully ten inches of precipitation and since evaporation from soil and foliage returns to the air about 70 percent of our precipi- tation, these two factors represent a significant portion of the hydrologic cycle and a determinant of our water resources. (See Figure VII-2) Further, and less often noted, the relations of precipitation, evaporation, and stor- age will determine the escape of soluble substances such as nitrate from the region of roots and into groundwater and streams. Because the plant roots are inter- twined among the soil particles and water flows readily from one to the other, plant and soil — and, for that matter, the atmosphere as well — - must be analyzed as a continuous system. Then the components can be examined in order of their impact on the system, and the results used to improve our understanding and ability to predict the functioning of the entire system outdoors. Fortu- nately, our ability to cope with the entire system has been advanced materially in recent years. Total Evaporation Essentially, the soil-plant-water problem is to measure the extraction from the soil, conduction to the leaves, and then evaporation from the leaves. Some water may short- circuit this path and be evaporated from the soil or leach beyond the roots, but a lot — often most — takes the route of soil to plant to air. Evaporation from the Canopy — Recently, research has greatly im- proved our understanding of how water gets from the canopy of foliage to the atmosphere above. When evaporation from the canopy strata is viewed as a factor in an energy budget and evaporation and convec- tion are set proportional to tempera- ture and humidity differences, the evaporation (and the temperature and humidity of the air within the canopy microclimate) can be calculated from the weather above and below the canopy, the profiles of radiation and ventilation, the distribution of foliage area, and the boundary layer and stomatal resistance of the foliage. In 200 RCES Figure VII-2 — THE HYDROLOGIC CYCLE \d, EVAPORATION FROM THE SEA 367 Domestic and Industrial needs (Units of measure in cc) S — Surface Runoff P — Percolation U— Uptake R — Residual This is an idealized version of the water cycle. The numbers attached to the various processes are relative units of measure. Note that the truly important parts of the cycle are evaporation from the sea, precipitation, and evapotranspiration. 1956, Penman showed how evapora- tion from abundant foliage suffici- ently wet to have wide stomata could be calculated from the net all-wave radiation available above the canopy. The recent advance is, therefore, in understanding how foliage condition can decrease evaporation below Pen- man's potential and how the evapora- tion and consequent temperature and humidity within the canopy are changed. The total evaporation from the canopy, according to our new understanding, is affected profoundly by the leaf area and, more subtly, but still considerably, by the stomatal conductivity or porosity of the foliage for water. Future Observations and Experi- ments — This understanding has been arrived at by means of mathematical simulation. To make a substantial improvement in our understanding — or even to test our present under- standing — future measurements of evaporation from crops and trees must include observations of leaf area and porosity as well as weather and evaporation. Fortunately, since the invention of a simple, portable porometer by Wallihan in 1964 and the subsequent calibration of several modifications, porosity can easily be measured. Earlier hydrologic observations sug- gested that different vegetation con- sumed different amounts of water in evaporation. The simulators men- tioned above, along with experiments with sprays that shrink stomata, have now established that evaporation can be changed by modest changes in the canopy. During the coming years, therefore, one can expect a variety of experiments seeking the most effec- tive and least injurious ways of con- serving water in the soil through treating or modifying the vegetation. Microclimatic Measurements Turning to the distribution of evaporation, temperature, and hu- midity within the canopy — in con- trast to the sum of evaporation discussed above — one finds that a greater number of parameters can be effective. The changes in tem- perature and humidity along the path conducting water and sensible heat out of the canopy depend on the boundary layer around the leaf and the turbulence of the bulk air within the canopy. These two factors gen- erally are of smaller magnitude than the stomatal resistance and hence are relatively ineffective, we believe, in changing the sum of evaporation. However, when we turn to the distribution of temperature and hu- midity within the canopy — the mi- croclimatic question — these param- eters are influential. Scientists do not yet know how to measure them, however. Boundary-Layer Resistance — For- merly, this was estimated from a conventional fluid mechanics equa- tion, employing the square root of leaf dimension divided by wind speed. Recently, however, Hunt and 201 PART VII — WATER RESOURCES, FORESTRY, AND AGRICULTURE others have claimed that this estimate is greater than the true resistance within a canopy. Presumably, this question can be resolved by fluid mechanics, energy budgets, and the new porometers. Diffusivity Within the Canopy — This is harder to measure. At present it is estimated by measurements of radiation absorption and tem- perature and humidity gradients. The method is susceptible to error, produces estimates at variance with the wind speed and employs the very temperatures and humidities that one would like to predict. A new method of estimating diffusivities within the canopy is required but none has yet appeared. Microclimatic observation will un- doubtedly continue in the future. If the observations are to be most useful in testing and improving our under- standing, they should include the ver- tical variation in leaf area and poros- ity as well as radiation, temperature, humidity, and ventilation. Since this makes a formidable list of equip- ment and tasks before a complete, and hence worthwhile, set of ob- servations can be made, microclimatic and evaporation studies seem ideally suited as testing grounds for coop- erative or integrated teams of sci- entists. Horizontal Heterogeneities — The final remark concerning the aerial portion of the problem must concern horizontal heterogeneity and advec- tion. Chimneys and sun flecks among the foliage clearly render our ideal, stratified models unrealistic. There- fore, efforts to incorporate these heterogeneities into the analysis are welcomed, even if they only prove that the ideal, homogeneous model gives the same average evaporation and microclimate as the realistic model. The larger heterogeneities con- noted by "advection" are known to be important, justifying the term "oasis effect." Advection of carbon dioxide has already been treated simply in a photosynthesis model, and incorporating large-scale advec- tion into the existing evaporation models seems manageable and worth- while. Water Storage in Soil The transport of water to foliage from soil has not yet been mentioned. Relatively less can be said about it in a systematic way. As a comple- ment to the simulation of evaporation from foliage, we need a comprehen- sive simulator of this portion of the path of the water that will tell us how much water gets to the leaves and, more important, how stomatal resistance is modified. The simulator concerning soil and plant is more lacking in foundation than one con- cerning plant and air. Nevertheless, beginnings have been made by Cowan and Raschke. Gaps in Scientific Understanding — These primitive simulators reveal se- rious deficiencies in our understand- ing of (a) the relation between water potential in the leaves and stomatal resistance; (b) the conductivity of different root regions; and (c) the conductivity between soil and roots. This last matter includes the dif- ficult problem of root distribution through the soil profile. The actual storage capacity of the soil and rela- tion between potential and content seem fairly well established. The effect of changes of temperature in time and depth is yet to be coped with. New instruments usable in the field should help. The new porom- eters have been mentioned already, and the Scholander pressure chamber promises to reveal water potentials, even in roots. We are still left, how- ever, to search for root distributions. In the case of temperature differences, on the other hand, the problem is to improve our logic rather than our observations. The next problem is the escape of water from soil storage via a moist surface or by leaching rather than through vegetation. These two es- capes greatly affect the loss from the root zone of salts and nutrients that pollute the water below. Evaporation and land leaching from the soil have been measured carefully in bare soil, but the present challenge is to under- stand the parameters sufficiently well to estimate them when a canopy of foliage is also removing water. This is a fundamental problem of the movement and loss of water from a heterogeneous porous medium with a variable and heterogeneous tempera- ture. The research of the past has not brought us a lucid understanding of the system; at present, progress seems most likely to come from de- vising a better logical framework on which to hang our measurements. A Final Word The reader may have noticed that time has not been mentioned. That is, analyses or simulators of an in- stant only have been described. In- tellectual satisfaction and eventual utility requires that our understand- ing and predictors be extended through time, with the storage of plant and soil as parameters. 202 I A Note on Subsidence and the Exhaustion of Water-Bearing and Oil-Bearing Formations Virtually all rocks near the earth's surface are to some degree porous, and if water is available it fills the pores. In some rocks the pores are large enough and well enough inter- connected so that water can readily flow from volumes of higher pres- sure to volumes of lower; such rocks are called aquifers — water bearers. Other rocks have pores so fine and so poorly interconnected that water passes through them only slowly, even under high pressure-gradients; these are aquitards — water-retarders. Among the common rocks, sand- stones, conglomerates, cavernous limestone, and scoriaceous lavas are the chief aquifers; shales are the principal aquitards. Subsidence Where water has access to an inter- bedded series of aquitards and aqui- fers both are commonly saturated, but the aquitards are sufficiently im- permeable as to permit considerable pressure differences to exist between the several aquifers. When a well is drilled to any particular confined aquifer and water is withdrawn from it, the water pressure in the aquifer is decreased and the aquifer shrinks in thickness. The weight of the rocks overlying the aquifer, which had formerly been in part sustained by the pressure of the contained water on the base of the overlying aquitard, has become effectively greater because of the decrease in hydrostatic pressure; under the ef- fectively greater load, the aquifer yields elastically and the volume of its pores diminishes. Though Young's modulus for most sandstones is between 140,000 and 500,000 pounds per square inch, a significant pressure reduction in an aquifer several hundred feet thick can readily cause a subsidence of several feet at the surface of the ground. Such a subsidence may cre- ate serious problems in drainage, sew- age disposal, and utility maintenance. More important than simple elastic compression of the aquifers, how- ever, is the fact that the lowered pressure in the aquifers permits slow drainage into them from adjoining or interbedded aquitards. This per- mits the aquitards also to be com- pressed by shrinking their pore spaces. Thus, at the Wilmington oil field, in California, the loss of pressure in the oil sands after 1936, when production on a large scale began, led to a surface subsidence of more than 32 feet (see Figure VII-3) before recharging of the oil sands with sea water under pressure finally stabilized the surface. Of this subsidence, only about 10 feet could be attributed to elastic compression of the oil sands; the remaining 22 feet was almost cer- tainly due to de-watering of the asso- ciated shales. The cost of this sub- sidence was many millions of dollars, since the railroad terminals, docks, shipyards, drydocks, and power plants had all to be rebuilt, together with the streets, water, and sewer systems of a large part of the city of Wilmington. Similar subsidence caused by with- drawal of fluids under pressure has been noted at many other seaside localities: Lake Maracaibo, Vene- zuela; Goose Creek, Texas; Hunting- ton Beach, California; Redondo Beach, California. None caused as great a loss as that at Wilmington. It is possible for similar subsidence to pass unnoticed at areas inland be- Figure VII-3 — SUBSIDENCE IN LONG BEACH, CALIFORNIA (Illustration Courtesy of the Geological Society of America ) Superimposed on the photograph of the port area of Long Beach, California are contours of equal subsidence in feet as they existed in 1962. The subsidence in the upper right resulted from withdrawal of fluid from the Signal Hill oil field be- tween 1928 and 1962. The major subsidence in the foreground was due to with- drawal from the Wilmington oil field. 203 PART VII — WATER RESOURCES, FORESTRY, AND AGRICULTURE cause a definite reference surface is not obvious. Nevertheless, the failure of the Baldwin Hills Dam in western Los Angeles, with the loss of many lives and millions in property damage, was probably due to withdrawal of fluids from the underlying oil field. The subsidence of many feet beneath the city of Mexico was caused by withdrawal of water from the lake sediments on which the city was built; considerable expenditures have been needed to take care of drainage disposal. Two other areas in California have suffered large losses through with- drawal of water from beneath. In the Santa Clara Valley, pumping of water from a confined aquifer at depth has led to subsidence as great as 9 feet between 1934 and 1959 in the city of San Jose; subsidence has also been considerable farther north in the valley, including such important industrial areas as Sunnyvale. On the west side of the San Joa- quin Valley, dewatering of surficial sediments had caused the surface to subside as much as 23 feet by 1963 and forced alterations in the plans for the new irrigation system now under construction. Exhaustion of Groundwater Most of the agricultural produc- tion of the High Plains of Texas and eastern New Mexico tributary to the cities of Lubbock, Amarillo, and Por- tales depends on water pumped from the Ogallala Formation, of Pliocene age. The Ogallala is composed of gravel and sand that was deposited as a piedmont fan from the Rocky Mountains to the northwest. Erosion since its deposition has cut deeply enough to sever the connection with the mountain streams whose sedi- ments led to the formation. The result is that water pumped from the forma- tion is not being recharged from the mountains; the small amount of recharge that feeds into the under- ground reservoir is simply seepage from the overlying arid surface. Es- timates by the Texas Agricultural Experiment Station were that re- charge amounts to only about 104,000 to 346,000 acre feet of water for the Texas portion of the High Plains, whereas pumpage averaged 5 million acre feet during the period from 1954 to 1961. Obviously, the water table is sinking at a tremendous rate, ranging from 1.34 to as much as 3.72 feet per year, and the cost of pumping is rising accordingly. The water is being mined, just as literally as is coal from a coal seam, and a drastic change in the economics of the region is unavoidable. The Texas study projects the de- cline in irrigated acreage from 3.5 million acres in 1966 to 125,000 acres in 2015. Cotton production is ex- pected to decline from about a million bales in 1966 to 355,000 bales in 2015, of which 70 percent will be grown on dry land. At 1966 prices, the aggregate annual value of agricul- tural production is projected to de- cline 70 percent in fifty years. Drastic economic change is clearly in sight, not only for the farm operators but for suppliers of farm machinery, auto- mobiles, and other inputs into agri- culture. Urban decline is also in- evitable. Water is being mined at many other places west of the 100th merid- ian — notably in the Mojave Desert of California and many of the inter- montane valleys of the Basin and Range Province in Arizona, Cali- fornia, Nevada, Utah, and Oregon. In each of these, results comparable to the inevitable decline of the High Plains are foreseeable, though the rate of decline will vary from area to area. 204 2. FORESTRY Water Quality in Forests Lands classified as forest, approxi- mately three-quarters of them in private ownership (see Figure VII-4) make up almost exactly one-third of the total land area of the United States. A large portion of this is well supplied with precipitation, and the excess over that lost by evapotran- spiration is the source of much of the water reaching streams, lakes, and ground waters. Water issuing from essentially un- disturbed forests, even those on steep terrain or with thin or erosive soils, is ordinarily of high quality — low in dissolved and suspended matter except during major floods, high in oxygen content, relatively low in temperature, and substantially free of microbial pollutants. These qual- ities are desirable and highly visible to recreational users of these lands, and some are absolutely essential to fish such as trout and salmon. They are also highly important to down- stream users, whether agricultural, urban, or industrial. In addition to any legal rights these users may have acquired to water volume, they of- ten have built-in dependencies — aes- thetic, technical, or economic — on quality features; they are commonly prepared to resist any real or prospec- tive impairment, regardless of the interests of the owners of the lands from which the water comes or other social claims on its use. Nevertheless, these water-yielding lands are required for a variety of other goods and social purposes — timber, recreation in many forms, grazing and wildlife production. A very large proportion of public and private land is held especially for such uses, whereas only rarely is there any direct recompense to the landholder for the outflowing waters. Despite contrary advocacy, it will sel- dom be defensible to propose water quality as the exclusive goal of forest land management over large areas. Now, all uses, all manipulation of soil and vegetation, pose some poten- tial risk to water quality — sometimes major, sometimes trivial. Even wild- erness camping, construction of roads essential for adequate fire protection, or forest cutting or herbicide treat- ments to reduce transpiration and so increase water yield conceivably could affect water quality adversely. Ac- cordingly, conflict between absolutely unaltered water quality and other land uses will likely be inevitable at times, and may have to be resolved on economic or political grounds. Moreover, conflicts between compet- ing land uses — as forage versus timber, large game versus domestic animal grazing, industrial raw ma- terials versus scenic impact — may be resolved on grounds other than water quality. But there is abundant evidence — chiefly from U.S. Forest Service ex- perimental watersheds — to demon- strate that other uses of watershed lands either already are or can be made compatible with essentially un- impaired water quality. A variety of techniques and constraints will be needed, such as where and how roads are built, the nature and timing of silvicultural or harvesting practices, how recreationists travel and camp. Many of these are known already; others are under investigation; still Figure VII-4 — OWNERSHIP OF U.S. FOREST LANDS The diagram shows the forest ownership pattern in the U.S. in 1952. Federal, state, and local governments owned only 27 percent of the forest land. An additional 13 percent was under the control of forest industries. Such a situation makes forest management difficult because many private owners lack the incentive, knowledge, or interest to use approved forestry practices on their lands. 205 PART VII — WATER RESOURCES, FORESTRY, AND AGRICULTURE others must be devised. In a few fragile landscapes only limited ac- cess and use may be allowable. There can be no simple, universal prescriptions for reconciling conflict- ing uses with each other or with water quality. The land classified as forest comprises an enormous number of combinations of vegetation types, soil and bedrock characteristics, land- forms and slopes, and climatic re- gimes. The latter include variation in total precipitation, its distribution and intensity on the watersheds, and features such as snowpack accumula- tion. This great number of combina- tions prevents easy generalization of studies on one watershed to others with different soil, slope, or precipi- tation features. It also emphasizes the need for much better charac- terization data — climate, geology, hydrology, and soils — for many important watershed regions, for in- vestigation of predictive models, and for expansion of on-the-ground "adaptive research" aimed at convert- ing principles discovered thus far into locally feasible guides for day-to- day operation. Factors Affecting Water Quality To a considerable degree, water quality has always figured in a larger concern with the protective function of forest cover upon stream flow — that is, flood control, water yield, and watershed maintenance or im- provement. The same natural or man-induced features that make for low infiltration rates, rapid surface runoff, and reduced storage in the soil mantle also lead variously to higher flood peaks but reduced flows in low water periods, to surface ero- sion and channel cutting, to sedimen- tation of downstream channels and empoundments, and to high turbidi- ties and sometimes high contents of material swept from the soil surface. Thus, turbidity and sediment content are valuable indices of impairment or improvement of the protective function of watershed, in addition to being direct measures of water quality. Water "quality" is a nebulous fea- ture until described in terms of spe- cific attributes such as turbidity, or- ganic content, temperature, nitrate, phosphate, pesticide or other chemical content, and bacteriological quality. These are sometimes discussed as considerations of equal probability, hazard, and rank, but in fact, turn out to be far from equivalent in any respect. Temperature and Oxygen — Re- moval of trees or brush greatly in- creases direct radiation to small streams and materially raises maxi- mum temperatures in the warm sea- sons— up to 7 to 8 centigrade higher, according to some studies. Such increases may be unfavorable or lethal to desirable fish, especially to salmon and trout species which spawn in small headwater streams, and they also contribute to higher average temperatures of downstream waters. The physical basis of this effect is fairly straightforward, of course, and the temperature in- crease of small streams has been predicted quite accurately through use of an energy-balance technique. Experimental observations are lim- ited and there can be no generaliza- tion about the importance of this effect to quite different climate and ecological regions. Within the Pacific Northwest, however, knowledge of temperature increase and oxygen de- crease following removal of cover is sufficient to call for protection of spawning waters. A highly effective management remedy is to leave narrow strips of live vegetation for shade; such strips are also important safeguards against stream or bank disturbance by log- ging operations. Such remedies may entail substantial sacrifice of timber values, as well as higher costs for harvesting and regeneration, and ap- plication may well hinge on benefit/ cost analyses. Further, one can fore- see occasional instances of con- flict between retention of shade and decreased water temperature on the one hand, and efforts to increase low water flow through reducing vegetation in the riparian zone on the other. Pesticides — A number of plant- protection or plant-control chemicals have been applied to forest vegeta- tion, and the need for such agents will certainly continue even though particular classes of compounds, such as chlorinated hydrocarbons, are banned. Reduction of losses during major insect outbreaks, control of competing vegetation, and protection of new plantations or regeneration areas are three common situations in which use of chemicals might be essential to timber, recreation, or watershed values. In principle, any such materials might enter streams either by direct application from aircraft or sprayers, or after washing over or through the soil, or through gross spills and carelessness. The first of these is sometimes thought to be the major concern, although the latter is likely to be the most difficult to predict and control. For the most part, the compounds applied to forests will be similar to those used elsewhere in properties such as persistence, toxicity, mode of decomposition, and fixation or accumulation by soil, and will be subject to similar precautions. In some instances, however, there may be special problems of forest use aris- ing from difficulties of precise appli- cation on rough terrain, or to coarse or rocky soils, or to the possibility of rapid, short-distance transport into streams — as, for example, after treatment of riparian areas. Further- more, the quality standards applied to headwater streams may well be more stringent than tolerated else- where. But in all this it should not be forgotten that by far the largest frac- 206 I (RESTS tion of forested land is entirely un- treated with pesticides of any sort, and the greatest part of the remainder would be treated only at intervals of several to many years. For ex- ample, a single application of 2,4,5-T to control overtopping brush on re- generation areas probably would not be repeated within the life of the new stand. Numerous monitoring studies with insecticides such as DDT and its suc- cessor materials during the past two decades have demonstrated the mag- nitude of direct and secondary input into streams to be expected from broadcast aerial applications. These also indicate both the hazards of applying highly toxic or persistent materials in this way and the meas- ures required to avoid or minimize direct contamination of waters. Again, fewer though significant studies with ground and aerial applications of herbicides demonstrate that careful regulation of mode, rate, and season of application allows use even in streamside areas with no or minimal contamination. Since phenoxy and amitrole herbicides degrade fairly rapidly in the forest floor, confining application to places and seasons where overland flow will not occur within a month or two avoids possible runoff. But, plainly, continued systematic experiments with pesticides or other easily detected markers under a large variety of field conditions is needed to insure a high degree of predictabil- ity. Moreover, the increasing con- straint on the use of some materials is likely to place a high emphasis on development of nontoxic or easily decomposed materials, and on alter- native strategies of pest control. The Effects of Fire — Concentra- tions of dissolved solids in forest streams are normally low, and in- creases of any magnitude are usually associated with major disturbances or additions. From time to time concern has been expressed over the effects of fire, clearcutting or other destruction of cover, increased area of nitrogen-fixing vegetation, and forest fertilization. Unfortunately, at- tention is sometimes directed solely to maximum concentrations in the waters from the affected areas. When the aggregate of small watersheds forming a single forested drainage basin is viewed as a system over time, however, events affecting small areas and at long intervals, such as clearcutting in a sustained-yield for- est, necessarily have only minor in- fluences on the quality of large- volume streams issuing from the entire basin. In contrast, drastic large-area events such as a major wildfire or insect pandemic could increase outflow concentrations for a relatively brief period. Plant ash remaining after severe fires can temporarily raise the base content and alkalinity of streams from affected areas. Accelerated de- composition of organic matter in and on the mineral surface after fire may increase nutrient outflow, though this has not been demonstrated. These several changes are probably trivial, however, in comparison with more serious and long-lasting effects on water temperature, turbidity, and flow characteristics, especially if re- establishment of cover is long de- layed. But fires are of many kinds, and forest landscapes vary enormously in susceptibility to post-fire erosion. Turbid streams, floods, and disastrous mudflows are well-known conse- quences of fire in the steep brush- lands of southern California. (See Figure VII-5) There are many such landscapes with highly combustible vegetation where uncontrolled fire is a major hazard to watershed values, including water quality. Well-docu- mented case histories, as well as small-scale experiments, thoroughly demonstrate the flood peaks, gulley- ing, sediment transport, and channel tilling, as well as long-term impair- ment of water quality following severe wildfires on sensitive soils and slopes. Hence, research on fire be- havior and control, fuel reduction prescribed fire, and wildfire detec- tion and suppression are essential to maintenance of water quality. This point is too often overlooked, and efforts at economic analyses or "total social costs" fail to weigh the proba- bility— and overwhelming damage — of major wildfires against the costs and minor damages of roads or other measures that facilitate fire control. Disastrous effects on water quality from wildfire are far from universal, however. In some places, wildfire may be followed by significant sur- face washing or mass movement but part or all of the sediment comes to rest and is stabilized before reaching the streams. Furthermore, there are large areas of stable soils and slopes that resist detachment and maintain adequate hydrologic capabilities even after severe fires. Much remains to be learned about soil and water behavior following fire, and especially about mass move- ment on steep or unstable slopes, about the possibilities of adverse precipitation events in the interval before revegetation of newly burned surfaces, and about seeding or other measures to hasten such revegetation. The sheer magnitude and obviousness of the immediate post-fire conse- quences, the costs and complexities of long-term studies on large burns, and concern with newer threats to water quality tend to divert attention from quantitative studies of recovery processes. Nevertheless, present knowledge allows arraying likelihood and pos- sible extent of wildfire influences on a scale from none to very great, according to landscapes, fuel type, and fire characteristics. Such knowl- edge also allows use of prescribed fire, at times of low hazard, for a variety of purposes — preparation for regeneration, improvement of wild- life habitat, and, notably, reduction of accumulated fire fuels that would otherwise vastly increase wildfire hazards. In most of the southern 207 PART VII — WATER RESOURCES, FORESTRY, AND AGRICULTURE Figure VII-5 — EFFECTS OF FOREST FIRES The upper photograph shows an orchard near Santa Barbara, California. The single open storm drain was normally adequate to handle storm runoff. In 1941, however, the region enclosed by the dotted line was burned out in a brush fire. The lower photograph shows the debris deposited by the runoff of a single light rain after the fire. pine forests prescribed fire is actually a legacy from annual burning by Indian populations, and several stud- ies fail to show any deleterious con- sequences of its repeated use. Known or probable exceptions, however, are some areas of new forests planted on severely eroded lands, and some steep and sensitive soils. Again, some studies of "slash burning" for reduc- tion of logging debris in the Douglas fir region reveal that the soil cover is totally removed from only a small percentage of the burned area so that infiltration remains high and sedimentation negligible. But greater fire severity, or slopes on which mass movement occurs, increases the likeli- hood of soil movement into stream channels. Generally feasible alterna- tives to fire have not yet been found, but several interests — includ- ing smoke abatement, possible value of logging wastes, and fish manage- ment, as well as water quality per se — have encouraged such research. In some regions the predominance of alder and some other nitrogen- fixing shrub species can be increased by fires, disturbance, or silvicultural treatment. Stands of alders fix sig- nificant quantities of atmospheric nitrogen, and some fraction of this addition enters streams. The extent of such contributions and their even- tual effect on stream concentrations are unknown, except by order-of- magnitude estimates. However, these indicate that fixation per unit area over a period of some years must often exceed the nitrogen additions considered in forest fertilization pro- posals. Hence, consequences of these natural additions are of very con- siderable interest. Reduction of the forest cover by fire, wind, insects, and clearcutting causes an abrupt increase in surface temperatures and in mineralization of the organic matter. The resulting nutrient release may be followed by increased leaching of nitrates and as- sociated cations into streams. These effects are highly dependent on cli- mate and the quantity of surface organic matter, and on the rapidity with which a new cover of vegetation appears. The well-known studies at Hubbard Brook (New Hampshire), although artificial in some degree, served to focus attention on the maximum quantities of nutrients that may thus enter streams. Several other studies in regions of lesser organic accumulation and where natural re- vegetation is allowed, show only minor increases. A considerable number of experimental treatments and monitoring to study this effect further are now under way. Virtually no attention has been given to other forest management treatments which probably act in the same direction although at lower intensity. These are drainage of for- ested wetlands, broadcast burning, and site preparation by destroying vegetation and disturbing the soil. 208 FORF.STS The exact magnitude will be highly variable, depending on soil and cli- mate. The effects of all such treat- ments on nutrient release, like those of clearcutting, are temporary, self- limiting, and not subject to recur- rence on the same area within the foreseeable future. Though these nutrient changes may be conse- quential for vegetation on the treated area, estimates suggest that any in- fluence on water quality must be slight. The Effects of Fertilizers and Other Nutrient Sources — In recent years there has been a sharp increase in the number of experiments and op- erational trials using artificial fer- tilizers to increase timber growth and wildlife food supplies, and to develop protective vegetation on disturbed or eroded soils. Large-scale applications of nitrogen on timberlands, notably in the Pacific Northwest, have pro- voked concern that the added fer- tilizer would enter streams and lakes, increasing eutrophication and perhaps reducing quality of urban water sup- plies. Several lines of evidence, including lysimeter studies on fertilized areas as well as the "clean-up" of sewage and other waste waters applied to forest soils, demonstrate that forest ecosystems are highly efficient col- lectors and "sinks" for added nutri- ents. The capacity of such sinks ap- pears great due to the large biomass low in nutrient content, wide carbon- nitrogen ratios of forest organic mat- ter, and the high phosphorus-fixing capabilities of most mineral soils; but the details are poorly known. Again, the possibility of increased nutrient content in soil and vegetation result- ing from fertilization has raised the possibility of greater release follow- ing timber harvest. Such questions point to the need for far more precise characterizations of the "compart- ments" and "fluxes" of ecosystem models before these can have any predictive value. Present knowledge of the fate of nutrients entering the soil indicates that the more serious source of water contamination would be direct entry of the applied fertilizers into streams and lakes. This might occur either through the distribution into such waters during aerial application, or in consequence of surface washing at some periods of the year. The latter chiefly concerns the borders of streams and the associated system of "temporary" streams where over- land flow mass occurs briefly at pe- riods when the underlying soil is saturated. The extent of such channel expansion and its role in transport of dissolved or fine suspended mat- ter has been generally overlooked. Thus far, however, the forest land managers involved have been highly sensitive to water-quality considera- tions and have withheld application of nitrogen fertilizers in the vicinity of lakes or streams. In consequence, the tolerable upper limits of rate and distribution are as yet unknown. But several studies of fertilized water- sheds and monitoring of streams from fertilized areas are already un- der way and will warrant continued attention. Another important localized source of nutrient enrichment comes about through the high concentrations of recreational users at major camp- grounds, ski developments, and the like. Treatment of the human waste generated at such areas may or may not render the effluent waters "micro- biologically safe," but the nitrogen and often the phosphorus contents usually enter the streams. The result- ing nutrient load is susceptible to reasonably accurate determination, but the effects on the biology of headwater streams and the magnitude of such enrichment in comparison with other sources mentioned above certainly require study. This problem is only marginally a concern of "for- est management," but in the face of steadily increasing recreational de- mands the solutions are likely to be difficult or expensive. Among the options will be prohibition of such use, elaborate treatment plants or new technologies of waste or acceptance of altered water qu In any case, both the projection of recreational expansion and hydrolog- tcal data on the streams should be adequate for prediction of conse- quences when such recreational uses are being considered. Bacteriological Quality — Increas- ing recreational use is also a major threat to bacteriological quality of water from forested areas. Small numbers of hikers and workers, like small stock and wildlife populations, can use a large area without making much impact. But in forest areas heavily used by campers, hikers, or workers human waste treatment is commonly inadequate, primitive, or nonexistent, posing possible hazards to downstream users of untreated waters from such areas. Routine treatment offsets any such threats in urban distribution systems but the problem of reconciling health, aes- thetics, and recreational use remains. Sediment, the Pre-eminent Fac- tor — Concern with the varied as- pects of water quality, though nec- essary, sometimes deflects attention from sediment load, which is the major, most costly, and almost ubiq- uitous cause of impaired quality. Fine suspended matter, mineral or organic, as "silt" or "turbidity," imposes high treatment costs for urban and some industrial uses. It also clogs irri- gation ditches, destroys spawning grounds and bottom vegetation, and reduces recreational and scenic val- ues. Coarse materials fill channels and divert streams in flood, and often destroy the usefulness of flooded lands. Sediment movement into streams, together with flow rate and land- treatment effects, have been the main thrust of watershed research. As a result, the sources of fine and coarse sediments in forest watersheds are reasonably well known, as are the general relationships between sedi- ment production on the one hand, and 209 PART VII — WATER RESOURCES, FORESTRY, AND AGRICULTURE Figure VII— 6 — RELATION OF SEDIMENT PARTICLE- SIZE TO FLOW RATE hon "i r 10 i r PERCENT J I L_ 10 20 SAND 30 40 50 60 SILT 70 20 30 CLAY 40 The graph shows lines of best fit for measurements of sediment particle-size dis- tribution made from 1961 to 1964 in the Scott Run basin, Fairfax County, Virginia. There appears to be no change in particle-size distribution with time. The low-flow regimes show high concentrations of silt and clay. As the flow decreases and the speed slows, the silt particles — being heavier — drop to the stream bed, leaving the fine clay particles to become the greater portion of the load. As the flow increases, there is an increasing concentration of the larger, sandy particles. hydrological behavior and disturb- ance of vegetation on the other. (See Figure VII-6) On the majority of forest water- sheds, the principal cause of erosion and stream turbidity outside of flood periods is exposure or disturbance of the mineral soil surface. This may come about through any of a number of causes — excessive grazing, tram- pling by livestock or humans in large numbers, roads and skid-trail con- struction, and, as mentioned, some- times after severe fire. Current overgrazing and the legacy from even more severe overgrazing in the past poses severe problems in some low-rainfall forest areas of western United States. Reducing fur- ther damage by livestock, and occa- sionally by big game, is more of a political-economic problem than one of technical know-how. Repair of past damage, however, is handi- capped by the large area and low values of affected lands, the slow pace of natural recovery, and limited funds for both research and applica- tion of known principles. Increasing recreational uses — in- cluding human traffic on trails and campgrounds, development of roads, ski runs, facilities, and now the large numbers of off-the-road ve- hicles — create an array of new prob- lems for forest land management. Obviously, hazard to water quality is only one of these, though often significant. Less obviously, new kinds of use conflicts are being generated, and research in behavior and values is likely to be as important in ad- dressing these as is that in economics and watershed management. Contrary to popular belief, the mere cutting of trees, even com- pletely and over large areas, seldom leads to any surface erosion, espe- cially if regrowth occurs promptly. The critical factor determining whether logging operations will or will not influence stream turbidity is how the felling, skidding, and hauling are conducted. There is now a substantial body of research and experience in several forest regions demonstrating that the mechanical operations and necessary road con- struction can be carried on with minor or no impact on watershed values and stream turbidity. Several essential principles of road design, construction, and mainte- nance, as well as for protection of stream channels, have emerged that minimize soil exposure and arrest sediment transport. These principles are readily translated into practice in many landscapes, though the op- erational details and controls are known for only a few. In some steep mountains or slide-prone areas, how- ever, geological structure and topog- raphy impose unforeseen hazards and extremely high costs. Greater avail- ability of soil and geotechnical in- formation might reduce both, though the resources for providing informa- tion to large wildland areas are meager. In any case, cost factors as well as watershed considerations have dictated new attention to harvesting and transport systems, including the long-used aerial cable methods and feasibility tests with balloon and heli- copter logging. 210 FORESTS Hence, with the exception of fragile or very steep lands, our pres- ent levels of knowledge and tech- nology are generally adequate to minimize these sources of disturbance or reduce their consequences. This is true even though many elements — including lack of exact prescriptions, increased costs, momentum of exist- ing systems, and unawareness of long-run damages — may cause ac- tual practice to lag well behind the prospects demonstrated by research. Needed Scientific Activity As the foregoing indicates, a sub- stantial body of knowledge and application has been accumulated through "watershed" or "watershed management" research on forest areas. Extension of research results and at least qualitative predictions to similar landscapes can be made with some confidence. Greater cer- tainty, exactness, and extent of pre- dictions are possible simply through increased funding of existing re- search installations. Predictive mod- els and simulation relating streamflow to physical variables and precipitation are being explored by hydrologists. Success would bring extension to forest watersheds for which numer- ous data are available, and might call for new modes of examining factors controlling surface soil loss, bank erosion, or other sources of turbidity. Nevertheless, even within current concepts, there are enormous gaps in our knowledge of watersheds. Many large areas are poorly known in terms of exact climatic data, soil units, and the hydrologic behavior or response of watersheds to treat- ment. In some instances, the simple conceptual models derived from study of soil in the laboratory or agricul- tural field bear little resemblance to the behavior of wildland soils, es- pecially those on very steep slopes. Much greater efforts at watershed characterization and in study of the actual functioning of small soil- geomorphic "systems" under field conditions are badly needed. Such work is not entirely lacking (see Figure VII— 7), but the investigators so employed are few and the number of mixed-discipline investigative teams far fewer, especially in the light of the large areas involved. Three examples illustrate such needs : 1. Only within the last decade has it been recognized that fire on the steep California brush- lands not only destroys the protective cover of vegetation and litter but also imparts a non-wettable quality to the soil itself, apparently through con- densation of heat-volatilized substances from the litter. The result is reduced entry of rain- fall, increased surface flow, and erosion. This complexity has required new research proaches, and calls for revision of existing notions of infiltra- tion in both burned and pro- tected soils. 2. Hewlett's variable source area concept of water outflow, al- luded to earlier, is still novel and its consequences for water quality are only now being ex- plored. In certain landscapes it seems to provide a mechan- ism for direct overland trans- port of surface materials to streams without passing through the soil filter, a pos- sibility usually overlooked. 3. Again, assessments of land- scape stability, normal sedi- ment loads, and tolerance of man-made disturbance are com- monly based on short time periods and assumptions of Figure VII-7 — EFFECT OF LAND USE ON SEDIMENT YIELD AND CHANNEL STABILITY Land use A. Natural forest or grassland. B. Heavily grazed areas. C. Cropping D. Retirement of land from cropping. E. Urban construction. F. Stabilization G. Stable urban Sediment yield Channel stability Low Relatively stable with some bank erosion. Low to moderate Somewhat less stable than A. Moderate to heavy _ Some aggradation and increased bank erosion. Low to moderate Increasing stability. Very heavy Rapid aggradation and some bank erosion. Moderate Degradation and severe bank erosion. Low to moderate Relatively stable. The table shows various land uses and their effect on the relative sediment yield from the surrounding landscape as well as on the stability of stream channels. The most severe sediment problems occur during urban construction, when covering vegetation is removed and the flow regime in channels is changed by realignments, increases or decreases in the flow, or obstructions placed in or alongside the natural flowway. 211 PART VII — WATER RESOURCES, FORESTRY, AND AGRICULTURE gradualness. But the geologic processes that shape the steep lands are often violent and er- ratic. Landslides, avalanches, massive floods, and abrupt changes in stream cutting and deposit are normal incidents in the down-wearing of steep mountain slopes. Since hazard is often unsuspected and fre- quency is on a larger scale than laymen reckon with, such events often appear as "ac- cidents" or are attributed to the wrong causes. It is clear that man's activities in some susceptible landscapes decades and centuries ago have increased the frequency or severity of such events and triggered self-accelerating erosion of unstable slopes. Now, landslides and slips associated with road con- struction are a continuing problem as roads are extended into steep remote areas. Hence, there is need for much better understanding of soil and geomorphic processes on vulnerable steep lands with a view to characterizing hazards and devis- ing measures of avoidance or control. Such research concerns not only forest management operations but equally highway construction, ski- slope developments, powerline clear- ance, mining, and all other activities that change stream courses, slope loading, or the stabilizing effects of vegetation. Factors Relating Forest Management to Water Quality Water derived from forested wa- tersheds is generally the highest- quality water found under natural conditions although, contrary to pop- ular opinion, water from pristine forest streams is frequently unsafe for human consumption. Under nat- ural conditions, water quality is a function of: Geology and Geochemistry — Par- ent materials and the products of their weathering influence mineral content. Topography — Elevation, exposure, and steepness influence the form of precipitation, time and mode of de- livery, evaporation rates, water tem- perature, infiltration opportunity. Climate — Climate influences or determines the amount and form of precipitation input and the time and mode of delivery of water; indirectly, it influences sediment and organic content, rate of weathering, soil de- velopment, and vegetative cover. Soils — Type and depth of soil mantle are significant factors in wa- ter quality determination, especially in surface water. They influence the rate and amount of infiltration and percolation and, consequently, quality and amount of groundwater recharge, the rate and amount of erosion, and, thus, the sediment and chemical con- tent of surface water. Soil influences biological activity and nutrient cy- cling processes and is a determining factor in type and density of vegeta- tive cover. Biota — Includes animal and plant forms. Animals, from soil bacteria and microorganisms to large wild- life forms, play a significant role in determining water quality. Similarly, vegetative forms from lowly mosses through forests exert an influence on water quality. These combined in- fluences include bacteria, nutrients, organic matter, and sediment or tur- bidity content, hydrogen ion activity, suspended solids, and water tempera- ture. Natural Disturbances — Natural ca- tastrophes including forest fires, in- sect and disease depradation, earth- quakes, volcanic eruptions, landslides, avalanches, hurricanes, and tornadoes all influence water quality, often in a major way. The Role of Forests Forest vegetation influences and in turn is influenced by climate, soil de- velopment, geologic weathering, other biota, and natural disturbances. Ex- amples of some forest influences which directly or indirectly affect water quality include: 1. An ameliorating influence on local climate leading to lower water temperatures and lower evaporation rates and also, usu- ally, to greater transpiration rates and higher production of atmospheric oxygen. 2. A favorable influence in reduc- ing flooding levels, erosion, and consequent sedimentation production and turbidity in streams. 3. A favorable influence in the area of nutrient cycling; more nutrients are held in and on forest land. 4. High production of organic matter may produce short-term discoloration, and sometimes odors, in surface water. At the same time, this organic material has a very favorable influence on biotic activity in and on soil. 5. Forest vegetation, particularly deep-rooted types, tend to pro- vide optimum natural protec- tion against avalanching and landslides. 6. Forests generally consume more water than other vegetation; thus, less total water may be available downstream for dilu- tion. 7. Forests tend to buffer highs and lows of streamflow volume and the quality of this water. 212 FORESTS Impacts of Forest Management on Water Quality Other than changes brought about by the (usually rare, except for forest fires) catastrophic natural disturb- ances over which we have little or no control, the major changes wrought in water quality from forested water- sheds are those resulting from man's activities. Major disturbances and and activities due to forest manage- ment and man's activities include: fire, forest clearing or removal, timber harvest, road and right-of-way con- struction, cultural operations, insect and disease control, solid waste dis- posal, and recreational activities and developments. Forest Fires — Whether natural, deliberate, accidental, or incendiary, forest fires are generally conceded to have a deleterious effect on water quality. The degree of influence de- pends on the type and intensity of the fire, the time of year, and topo- graphic and soil conditions. Ground fires occurring on stable soils may produce only minimal deterioration in water quality, while intense fires on sensitive soils and on steep slopes may occasion serious damage. Effects on water quality may be due to in- creased water temperatures, increased ash, mineral, and organic content, as well as higher sediment and turbidity loads due to increased runoff and ero- sion. The effects may be restricted to a single season or year or they may last up to several decades. Fire used as a management tool — e.g., to effect deliberate ecological change, to control insects and disease, or for slash disposal — is ordinarily planned in areas and at seasons when damage to water quality would be minimal. Forest Clearing — Removal of for- est for agricultural land use, for urban or industrial development, or for vege- tative-type conversion (e.g., forest to grass) may completely alter the water-quality regime. Changes will be greatest during the period of maxi- mum disturbance. Following recov- ery, the water-quality regime will take on the characteristics of the new land-use pattern. In some cases — e.g., the conversion of pinyon juniper or chapparal forest types to grass — there may be an improvement in water quality from the sediment- turbidity standpoint. Timber Harvest — The effects of timber harvesting on water quality will depend on the intensity and type of harvest operation and on the man- ner of product removal. Light selec- tion cuts will normally have minimal or no effect, while clear cuts that open up large areas will tend to increase water temperatures and increase the potential for subsequent erosion and sedimentation. Contrary to popular belief, the removal of the forest crop itself ordinarily does not occasion serious damage except on very steep slopes or on unusually sensitive soils. The major damage is usually due to harvesting and removal methods — i.e., skid trails, log landings, heavy- equipment disturbance, and, espe- cially, road construction and inade- quate maintenance. On occasion, yarding areas or equipment servicing areas may provide a source of con- tamination as a result of oil, gasoline, or chemical spills. Road Construction — Road and right-of-way construction in forests is a major problem insofar as water quality is concerned. During and fol- lowing clearing and construction, substantial areas of raw roadbed and cut-and-fill slopes are exposed to ero- sion; frequently, large amounts of erosional materials are washed into stream channels. Damage can be sub- stantially reduced through road loca- tion, carefully supervised construc- tion methods, immediate rehabili- tation of exposed areas, and good maintenance practices. The same holds true for the construction of rights-of-way for power lines, pipe- lines, and waterways (surface or un- derground). Cultural Operations — In addition to the harvesting process, intensive forest management may i; or more cultural operations such as forest thinnings and cleanings. When such operations are done mechani- cally, little or no impairment of water quality should result. However, when chemicals such as sodium arsenate or 2,4,5-T are applied, caution must be exercised to keep such materials away from streams. Insect and Disease Control — To protect commercial and noncommer- cial forests, wilderness, and recrea- tion areas as well as forest parks from periodic disease and insect epidemics, control operations are essential. The most effective and most economic control methods have involved chemi- cals such as DDT. The environmental dangers inherent in chemical control methods, including water-quality de- terioration, have become increasingly apparent and controls have recently been imposed. In some cases, con- trolled light ground fires in forest areas have been applied to destroy vectors. Such operations have little influence on water quality if applied carefully under controlled conditions. Ecologic controls also have little or no impact upon water quality. Solid Waste Disposal — In har- vesting timber crops as well as in the primary conversion (sawmilling), relatively large volumes of solid waste in the form of slash, slabs, and sawdust need disposal. To accelerate new forest development, to destroy breeding areas and food for forest insects and disease pests, and to en- hance the forest environment it has been a common practice to burn the forest slash. While such practices have only minimal effect on water quality, they are being halted in many forest areas due to air-pollution con- siderations. Similarly, at primary conversion plants there are major problems in the disposal of sawdust, slabs, and edgings. Again, fire has been used as a primary method of disposal but is now being drastically reduced due to air pollution. Some of this waste material is being used 213 PART VII — WATER RESOURCES, FORESTRY, AND AGRICULTURE to produce secondary products such as compressed-sawdust fireplace logs. Recreation Activity and Develop- ment — Outdoor recreation activity and developments in forest areas are increasing many-fold each year and are contributing to water-quality problems. Some of the forest wilder- ness areas are now badly overused, and lack of sanitation facilities and overuse by horse pack trains as well as human trampling are locally lower- ing water quality. A major problem in many forest areas results from in- creasing use by four-wheel-drive ve- hicles and trail motorcycles which increase erosion and add to sediment problems in streams. Recreation de- velopments in the forest ranging from camp and picnic grounds and summer homes to large ski areas are fre- quently poorly designed or poorly maintained from the standpoint of sanitation; they, too, are contributing to water-quality degradation. Other Forest Uses — Special uses of forest land — such as grazing by domestic livestock, mining opera- tions, and summer colonies or com- munes of people living on forest areas — may contribute special prob- lems in water quality. In general, grazing by domestic livestock is de- creasing on forest lands; conse- quently, from this standpoint an improvement in water quality can be expected. In mining operations in- volving large-scale land, subsurface disturbance, and road construction, water-quality problems increase, sometimes markedly, both from the standpoint of erosion and attendant sediment production and in mineral content of both surface and ground water. Steps Needed to Improve Water Quality While the quality of water derived from forest lands is in general supe- rior to that from other types of land- scapes or land uses, there is degrada- tion in many areas. Action is needed to protect water quality where it is good and to improve that which is being downgraded. Water-Quality Standards — By fed- eral legislation each state has had to set water-quality standards. Unfor- tunately, in many areas the standards set for some streams are higher than natural, or "pristine," water. For vari- ous reasons, many states lack back- ground data on natural water quality. If realistic standards are to be set and observed, some additional monitoring of forested water-source areas is needed. Application of Available Knowl- edge — In many instances, degrada- tion of water quality is due to lack of application of principles already known to us. More rigid require- ments can be written into timber sale and road construction and mainte- nance contracts and then enforced. Where sanitation facilities are inade- quate around recreation sites or sum- mer homes, forced improvement or closure can improve water quality. Closure or zoning of forest areas to specialized uses such as four-wheel- drive vehicles can be helpful. Re- duced use of sensitive wilderness areas or elimination of horse traffic in such areas is likewise an available tool. Neio Research — In many in- stances, remedial measures will be conditioned by the availability of new research information. Examples in- clude: What is the human carrying capacity in parks and forest recrea- tion areas with respect to water quality? What type of chemicals, and in what concentrations, can be used to control insects, diseases, and weed species without impairment of water quality? What type and pattern of forest harvesting can be safely ap- plied? At what seasons of the year should we restrict forest use to pro- tect water quality? What type of mineral extraction activity is permis- sible and what kinds of safeguards are necessary? How can forest areas be used safely and beneficially in solid waste disposal — wastes from the forest itself (slash) and from in- dustries and municipalities? What is the impact of watershed management activity to increase water yields on the water-quality regime? What are the relationships between wildlife use and domestic grazing and water quality? 214 3. AGRICULTURE Global Food Production Potentials By the development and applica- tion of technology in food production the world can be well fed generally, even with its prospective doubling of population by the year 2000. The physical, chemical, biological, and en- gineering sciences must be used to develop production systems that will effectively utilize arable land, water, solar energy, energy from fossil fuel or other source required for mechani- zation of agriculture, improved seeds, livestock, fertilizers, pesticide chemi- cals and other pest-protection means, genetics, ecology, disease and para- site control in man and animals, social science relevant to industrialization of agriculture and urbanization of the world generally, and the building and use of scientific and technological capability in every country to meet its needs. A great deal of science basic to agriculture has happened because men wanted to find out why — why tillage was useful — why fallow was useful — why ashes stimulated new plant growth. Man learned by expe- rience; he knew even in ancient times that good seed, in good soil, well watered under a friendly sun pro- duced a good harvest. The major plant nutrients required have been known for more than a hundred years. Commercial manufacture of superphosphates began about 1850, although nitrogen did not become available in Germany until World War I and in the United States until 1925. Mined potash and sulfur sup- plement natural reserves. Current Scientific Understanding The theoretical scientific basis of plant nutrition is an essential and major portion of the science basic to agriculture and world food produc- tion. Soils of the world vary widely in their reserves of major and minor plant nutrients. Some of them con- tain toxic amounts of such minerals as molybdenum or selenium. Others are very deficient. Amendment de- pends not alone on mineral analysis but also on the physical nature of the soil and its ion exchange capacity. The ability of the soil to produce crops must be assessed locally, often repetitively. It has been estimated that there are potentially arable lands in the world equal in area to those now under cultivation — i.e., around 1.5 billion hectares. (See Figure VII-8) One of the recommendations of the Presi- dent's Science Advisory Committee on The World Food Problem was: "The agricultural potential of vast areas of uncultivated lands, particu- larly in the tropical areas of Latin America and Africa, should be thor- oughly evaluated." Water is a major factor in all food production. The science of hydrol- ogy, the technology of water manage- ment are basic to agriculture. Irriga- tion — with its concomitant problems of waterlogging or drainage, salinity Figure VII-8 — POTENTIALLY ARABLE LAND IN RELATION TO WORLD POPULATION Continent Population in 1965 (millions of persons) Area in billions of acres Acres of culti- vated land per person Ratio of culti- vated to potentially arable land (percent) Total Poten- tially arable Culti- vated Africa 310 7.46 1.81 0.39 1.3 22 Asia .. . 1,855 6.76 1.55 1.28 .7 83 Australia and New Zealand 14 2.03 .38 .04 2.9 2 Europe 445 1.18 .43 .38 .9 88 North America 255 5.21 1.15 .59 2.3 51 South America 197 4.33 1.68 .19 1.0 11 U.S.S.R. Total 234 5.52 .88 .56 2.4 64 3,310 32.49 7.88 3.43 1.0 44 The table shows the total area of the continents of the world, the part that is po- tentially arable, and that which is presently being cultivated. The cultivated areas include land under crops, temporary fallow, temporary meadows, lands for mowing or pasture, market and kitchen gardens, fruit trees, vines, shrubs, and rubber planta- tions. The land actually harvested in any given year is about one-half to two-thirds of the total cultivated land. Of the potentially arable land, about 11 percent of the total requires irrigation for even one crop. It is important to note that Africa. Australia and New Zealand, and South America cultivate significantly less than half of their potentially arable land. The continents where most of the land is being used are those where the population density is greatest. 215 PART VII — WATER RESOURCES, FORESTRV AND AGRICULTURE or leaching — poses added problems for hydrologists and engineers. But these areas of science and technology are useless unless they are used in adequate systems of agronomy, in- volving knowledge of soil chemistry, soil physics, plant physiology, plant genetics, and soil-plant-water rela- tionships in every microclimate where crop plants are grown. Science basic to optimal use of solar energy and science basic to effective use of fossil fuel or other energy source in crop production, transportation, and storage and proc- essing of food crops is essential. In many countries, fossil fuel must be imported while human labor is in oversupply. Since a man is equivalent only to about one-eighth horsepower, it is difficult, if not impossible, to use enough human labor at the precise time when planting, harvesting, or cultivation is required. Crop-Plant Genetics and Breeding — Genetic capacity of crop plants and livestock species for the produc- tion of food useful and acceptable to man is a first requirement. Comes then the question of whether native plants and animals developed in and adapted to the many niches of a local ecosystem are better suited to serve man's needs there than those intro- duced from other places? The answer is that, for subsistence agriculture, the native varieties have many advantages. Natural selection over many generations has enabled them to survive the pests and com- peting organisms of their area of origin. But often this adaptation en- ables them to survive with only a meager excess for man's use. When man brings a new seed from a far place, it often fails in the new location; but not always. If it hap- pens to be adapted to the new loca- tion it may thrive there in the ab- sences of the diseases and pests it has left behind. Thus, sunflowers thrive in Hungary and the Ukraine while they are little exploited in their native Kansas, where they are weeds beset with many enemies. So, too, soybeans thrive in Illinois — far from their native China. Figure VII-9 shows two other transplanted species. Selection, sometimes rather simple phenotypic selection, has developed crop plant variants used in various parts of the world that are often pre- ferred for organoleptic quality though inferior in productivity. "Baking quality" in bread wheat is not useful in macaroni wheats, for example. Phenotypic selection continues to be an important crop-breeding tool. Science basic to plant breeding has contributed (a) controlled methods of hybridization that have added yield to some crop plants, especially maize; (b) dwarfism, which has made possi- ble dramatic yield increases through response to heavy fertilizer and water applications without lodging, espe- cially in rice, wheat, and sorghum; (c) genetic disease resistance, espe- cially resistance in wheat to rust; and (d) selective breeding for photoperiod Figure VII-9 — TRANSPLANTED SPECIES HEVEA RUBBER (HEVEA BRASILIENSIS) I Area of Origin JHH| Area of Transplanted Species COFFEE (COFFEA ARABICA) | Area of Origin II Area of Transplanted Species "0 S J? The map shows the area of origin of coffee (Coffea arabica) and hevea rubber (Hevea brasiliensis) and the areas where, having been transplanted, they are now principally cultivated. In its place of origin, coffee is subject to native red rust (Hemilaea vastatrix), whereas in the New World, no native diseases exist. Hevea rubber is found in the New World only in the wild. In the Old World, where major production takes place today, there are no native pests. 216 AGRICULTURE response suited to latitude, especially important in such crops as soybeans, maize, and wheat. Each country must have capability for continued breeding improvement of the crop plants it produces. Plant pathogens, for example, often de- velop new strains virulent to plants genetically resistant to old pathogens within a new crop plant generation. Animal Science — Aside from the relatively few true vegetarians in the world, who abstain from milk and eggs as well as from flesh, animal protein foods are status foods. Elas- ticity of demand for animal protein foods in the developing countries, in terms of consumer income, is very high. As income permits, these peo- ple will demand and obtain larger amounts of animal protein foods. While this demand may divert some cereals from human to animal food, most animal protein foods in the developing countries are and will continue to be produced from forage and milling offals and other products, including garbage, rejected as human food. There is, therefore, a very real need for the development of research and technological capability based on the animal sciences in all countries of the world. Among the principal problems re- quiring attention is research and tech- nology for the control and eradication of animal diseases, parasites, and the arthropod and other vectors of some of the major diseases of animals and man. An abbreviated list of the prin- cipal diseases would include foot-and- mouth disease, rinderpest, bovine pleuro-pneumonia, East Coast fever, African horse sickness, encephali- tides, African swine fever, malaria, trypanosomiasis, and schistosomiasis. Schistosomiasis is a major restraint on the full realization of the benefits of irrigation in tropical countries. The snail intermediate host of this para- site thrives in irrigation ditches. Two hundred million people are afflicted. Research is developing, or has de- veloped, control methods for all the diseases listed. Immunization, isola- tion, and vector control are all im- portant for one or more of them. Large game herbivores seem to be genetically resistant to, or tolerant of, some of these diseases. Research on propagation and management of such species may give new sources of ani- mal food. Fisheries as Food Sources — There is a very wide area of fisheries biol- ogy, culture, and engineering essen- tial to the scientific basis for world food production. Quantitatively, fish- eries constitute and have potential for only a minor portion of the world's food needs. However, in many nations they represent a quali- tatively excellent and preferred source of protein and concomitant minor nutrients essential to human health and well-being. Methods of harvest, preservation, and processing of ma- rine and estuarine fish and shellfish and methods of culture and propaga- tion of estuarine, coastal, and anad- romous species can protect and in- crease these sources of high-quality human food. In many countries, including our own, pond culture of carp, trout, cat- fish, crayfish, frogs, and other edible fresh-water species have a substan- tial potential for increasing supplies of preferred, high-quality protein foods. Beneficial eutrophication — utiliz- ing animal wastes as nutrients in controlled aquatic ecosystems — of- fers substantial potential for increas- ing food production, recycling wastes, and enhancing the quality of the en- vironment. Knowledge of fish and shellfish nutritive requirements, their reproductive requirements, their dis- eases and parasites, toxins and con- taminants, both chemical and biologi- cal are areas needing research and technological, institutional, and per- sonnel capability in many countries. Arctic and antarctic food produ tion might be increased by national and international management of the harvest of food species and regula- tion of numbers of competing non- food species. Food Protection — Achievement of the important objective that our food supply shall be safe and wholesome requires a basis in many sciences and a highly varied set of technological capabilities that must be available in every country. Among the principal problems are: material toxicants (alkaloid and others); mycotoxins, resulting from certain strains of mold, potent in parts per billion, carcinogenic in test animals; botulinus toxin — food-poi- soning organisms such as Salmonella; insect infestations; and spoilage or- ganisms. Protection by controlled environ- ments, chemicals, cold, and steriliza- tion requires intimate knowledge of the physical and chemical nature of food products and the effect of meth- ods of protection on nutritive and functional value and on safety and wholesomeness. In India, the National Council of Economic Advisers has estimated that insects take 15 percent of the stand- ing crop and another 10 percent after it is harvested and stored. Losses from rats are also severe both in fields and storage bins. Use of plant- protection chemicals increased from six million acres in 1955 to a current 200 million acres. New Directions for Science The world is principally dependent for its food supply on a very small number of crop and livestock species. Wheat, rice, rye, barley, oats, sor- ghum, maize and millet, sugarcane, sugar beets; potatoes, taco, cassava, sweet potatoes; soybeans, cowpeas, beans, and peas; vitamins, in variety, a little protein of fair quality from 217 PART VII — WATER RESOURCES, FORESTRY, AND AGRICULTURE cole crops and other green and yellow vegetables, from fruits and nuts, cattle, buffalo, sheep, goats, pigs; chickens, turkeys, ducks, and geese. Research is heavily concentrated on crops of commercial importance. Re- search on such crops and their com- mercial production does not help the subsistence farmer who must trade his small surplus for the necessities of life — salt, needles, cloth — that he is unable to produce. We need social science to guide us to the as- similation of the subsistence farmer into commercial agriculture or to urban industry. Until recently, ap- plied research in most developing countries was poorly financed and completely lacking in relevance to the problems of local farmers. Even where research was directed at pro- ducing practical results, it was gen- erally concentrated on cash crops for export rather than on basic food staples. It is not enough to produce high yields of nutritious grain. In India, prices for fine-grain rice from old, low-yielding native varieties are vir- tually unrestricted while prices of the coarser high-yielding varieties are controlled. Total production is re- duced by diversion of acres from high-yielding to low-yielding varie- ties. The affluent pay for what they want; the poorer consumers become dependent on rationed supplies of low-quality grain. The Institutions — Industrialized nations of the world have — in in- stitutions widely varying in structure — produced, taught, and applied the scientific information that is the basis of agricultural technology. In the United States, federal-state coopera- tion among the U.S. Department of Agriculture (USDA) and state agri- cultural experiment stations in each of the states provides a useful means of coordinating research, teaching, and service. Agricultural research has had the objective of producing results useful in improving the productive capacity of the land, the efficiency of crop, livestock, and forest production, the use of agricultural products, and the welfare of rural people. This system, while close-knit, is not closed. Inputs from all the sci- ence of the world and important con- tributions to it are commonplace. Shall at Princeton, East at Harvard, and Jones at the Connecticut Agri- cultural Experiment Station at New Haven all contributed to the scientific basis on which hybrid corn was de- veloped. But so, too, did a hundred others in USDA and the state agri- cultural experiment stations who painstakingly identified and modified the genetic stocks and the ways in which they could be used effectively in producing commercial seed for every latitude in which corn is grown. Developing nations must have their own institutions for agricultural teaching, research, and service. They emulate the model on which our Land Grant College system was conceived. They may find other organizations better suited to their needs. In any case, they must have institutions of their own to produce, teach, and ap- ply the science and resultant technol- ogy basic to efficient agriculture in a coordinated manner. The Hazard of Drought In most of the world, where men till the soil or graze animals, drought is a recurrent phenomenon. Given the preponderance of agriculture as a source of livelihood in the world, drought emerges as the major natural hazard of geophysical origin for man in terms of areal extent and numbers of population affected, if not in the intensity of harmful effects. Because it is a recurrent phenomenon, human adaptation or adjustment becomes possible. Indeed, most agricultural systems involve some adaptation. This statement takes as its starting point a human ecological context for the discussion of drought adaptation, illustrates the process of adjustment with two examples from widely dif- fering societies, and concludes with suggestions for the development of certain lines of scientific endeavor that promise to broaden the range of drought adjustment available to agri- culturists. What is Drought? In this ecological context, drought is defined as a shortage of water harmful to man's agricultural activi- ties. It occurs as an interaction be- tween an agricultural system and natural events which reduce the water available for plants and animals. The burden of drought is twofold, com- prising the actual losses of plant and animal production and the efforts expended to anticipate drought, and to prevent, reduce, or mitigate its effects. Several important concepts follow from this definition of drought. First, for the purpose of this statement, only agricultural drought is being exam- ined; plant-water relationships that affect, for example, watershed yield are not considered. Second, drought is a joint product of man and nature and is not to be equated with natural variation in moisture availability. Natural variation is intrinsic to natu- ral process and only has meaning for man in the context of human inter- action. Third, the measurement of successful adaptation is in the long- term reduction of the social burden of drought, not simply in the increase in agricultural yield. The scientific 218 i TURE effort required to improve human adaptation to drought must meet the same standards of efficacy, technical feasibility, favorable cost, and social acceptance that should govern any adaptive behavior. Farmer Adaptation to Drought In at least three parts of the world, the problem of human adaptation to drought is under continuing, inten- sive study. Saarinen has studied farmers' perceptions of the drought hazard on the semi-arid Great Plains of the United States; Heathcote has studied pastoral and agricultural farming in Australia; and Kates and Berry have carried out pilot studies of farmer perception among small- holders in Tanzania. By way of illus- tration, the work of Saarinen and Kates can be compared directly, using farmer interviews from comparatively dry areas of the respective countries. The focus in Figure VII-10 is on actions, on alternative adjustment strategies to reduce drought losses. The two studies were carried out quite independently; therefore, it is Figure VII-10 — COMPARATIVE PERCEPTIONS OF FEASIBLE ADJUSTMENTS TO DROUGHT TANZANIA FARMERS If the rains fail, what can a man do? ADJUSTMENTS No. of Replies Percent of Total Do nothing, wait. 17 12.14 Rainmaking, prayer. 15 10.71 Move to seek land, work, food. 51 36.43 Use stored food, saved money, sell cattle. 16 11.43 Change crops. 9 6.43 Irrigation. 15 10.71 Change plot location. 4 2.86 Change time of planting. 0.00 Change cultivation methods. 1 0.71 Others. 12 8.57 Adjustments per farmer = 1.07 99.99 U.S. FARMERS If a meeting were held and you were asked to give suggestions for reducing drought losses, what would you say? No. of ADJUSTMENTS Replies Percent of Total No suggestions 16 8.25 Rainmaking, prayer. 2 1.03 Quit farming. 1 0.52 Insurance, reserves, reduce expenditures, cattle. 16 8.25 Adapted crops. 2 1.03 Irrigation. 46 23.71 Change land character- istics by dams, ponds, trees, terraces. 26 13.40 Optimum seeding date. — 0.00 Cultivation: stubble mulch, summer fallow, minimum tillage, cover crops. 78 40.21 Others. 7 3.61 100.01 Adjustments per farmer = 2.02 The table shows the replies received from farmers in Tanzania and the United States when questioned about what they were willing to do in case of drought. Some 131 farmers in Tanzania and 96 in the U.S. were queried. In Tanzania, farmers mentioned an average of only one possible adjustment whereas U.S. farmers could think of an average of more than two to overcome the drought problem. of considerable interest th I from differently phrased questions are comparable. The available ceived strategies for mechanized U.S. grain farmers are not intrinsically different from those of hoe-cultivator Tanzanians. The mix of perceived adjustments differs, however — more actions in total being proffered by the U.S. farmers, more of these related to farm practices, and more of these requiring high-level technological in- puts. Tanzanian farmers seem more inclined to pursue adjustments not directly related to agricultural prac- tices, and thus are more prepared to change their livelihood pattern than to alter their specific cropping be- havior. Thus, the major contrast that emerges is between a flexible life pattern with an unchanging agri- cultural practice as opposed to a more rigid life pattern with an adaptive agricultural practice. These behav- ioral patterns are suggestive of either alternative perceptions of nature it- self or of opportunity for mobility. The Tanzanian farmer seems willing to move with an uncertain nature; his American counterpart appears readv to battle it out from a fixed site. Broadening the Range of Available Adaptive Behavior A farmer or rancher faces the re- current, often perennial choice of plant or grazing location, of the tim- ing of plant and cultivation, of the appropriate crops or stock, and of methods of cultivation and grazing. In seeking to broaden the agricul- turist's range of choice of drought adjustment, the scientist offers his usual and somewhat paradoxical knowledge: We know more about plant-water relationships than seems evident from the application of our knowledge; but we know less about these relationships than we need to know in order to apply the knowl- edge widely. Data Base — - We could now pro- vide for many parts of the world much improved information on which 219 PART VII — WATER RESOURCES, FORESTRY, AND AGRICULTURE to base these decisions. To do so we would need to bring together the scattered record of climate, the frag- mentary knowledge of soil, the dis- persed experience with varieties and breeds, and the complex measure- ments of the impact of cultivation or grazing practice on available soil moisture. Within a framework of water-balance accounting, simulated traces of climatic data can provide probabilities of moisture availability directly related to specific varietal needs or stocking patterns. If these probabilities are used as appropriate weights in programming models, crop yields may be balanced against drought risk, desirable planting times determined, or the role of labor- or capital-intensive moisture-conserv- ing practices assessed. A special role for the use of such data is for the planned agricultural settlement. Wherever men are in- duced to move to new, often strange environments, greater drought risks are often incurred as a function of their ignorance. The dust bowls of the American West, the Virgin Lands of the Soviet Union, and the Ground- nuts Scheme of colonial Tanganyika provide tragic evidence of the uni- versal cost of learning about new environments even with, or perhaps because of, the application of consid- erable technology. Thus, much might be done for both the indigenous and pioneer agriculturalist through the assemblage of the available data base, through the identification of missing information by systems analysis, through the filling of critical gaps by experiment and field research, and through the distillation of the final product in such form as to provide meaningful answers to the perennial questions of farmers, ranchers, and planners be they peasant or agro- industrial producers. Water-Saving Cultivation — A number of the critical gaps in our knowledge have already been identi- fied. For example, data on water- yield relationships in less than opti- mal conditions are difficult to obtain. We know for most plants how much water they need to survive and how much water they can use if water is readily available, but we know little about the trade-off between these two points. The breeding of new varieties has, to date, seemed to require more rather than less water for the high- yielding varieties; there seems little widespread exploration in breeding of the balance between yield and water need. Though some water-saving cultiva- tion methods are widely practiced, the actual effects of some measures are disputed, partly because these effects seem to vary greatly with soil, slope, rainfall, and cultivation prac- tice. For example, tie-ridging, a wa- ter-conserving practice in semi-arid tropical areas has a very mixed effect depending on the crop, soil, slope, and pattern of rainfall encountered. The proper timing of planting or grazing requires much more analysis. The probability of below-average rainfalls that might lead to drought is calculated in certain standard ways, usually involving the assumptions that rainfall events are independent and that the relative frequency or some mathematical isomorphism of historic events provides useful prob- abilities of future expectation. But neither of these approaches ade- quately forecasts the persistence of below-normal rainfall characteristic of drought conditions in temperate areas or the monsoonal delays asso- ciated with drought in tropical areas. Forecasts of persistence require knowledge of the climatic mechan- isms associated with the phenomenon and forecasts of monsoonal delay re- quire understanding of the associated weather systems. Irrigation — For a considerable part of the world, irrigation represents a crucial drought adaptation. But ir- rigation efficiency is notoriously low; the amount of water wasted prior to field application from conveyance, seepage, phreatophytes, or in misap- plication is very high. For all of these sources of water loss, the po- tential contribution from applied re- search is great. Nevertheless, in many parts of the world, water availability is far in advance of water utilization because farmers are slow to adopt the new system. It is with irrigation, as with the adoption of new hybrids or in the choice of any new adjustment, that the social sciences have a special role in bridging the technical isolation that characterizes much research and development and in placing such efforts into the ecological matrix of farmers' life styles, agricultural sys- tems, and socio-institutional settings. For many farmers, acceptance of ir- rigation literally means the accept- ance of a new way of life. Thus, the question is still wide open as to which farmers make the best settlers for the great new irrigation projects now on the drawing boards of many de- veloping countries. Or consider the achievements of the Green Revolu- tion. We are told that the rapid adoption of high-yielding rice and wheat, particularly in South Asia, will give needed breathing space in the critical Malthusian struggle for survival. But we are warned that such adoption comes at a cost of further stratifying rural society and intensifying existing trends that cre- ate classes of prosperous landowners and landless rural workers. An even more complex social interaction is found among farmers on the shores of Lake Victoria who seem to be shifting from drought-resistant millet to bird-resistant maize because their children, who formerly stayed in the fields at harvest time to protect the crops from bird pests, are now in school! All of the foregoing, the propen- sity to adopt innovations, rural class stratification, even bird pests, are factors capable of analysis, if not solution, within a framework of hu- man ecological systems analysis. But just as plant breeders have had to develop strategies of genetic change and varietal development capable of providing new strains quickly, so 220 AGRICULTURE must social scientists begin to de- velop analytic frameworks capable of accepting varied data and providing better, if not the best, answers. Priorities for Scientific Effort Priorities for scientific effort de- signed to broaden the range of choice available to those who are subject to recurrent drought can be listed as follows: 1. The assemblage and analysis of existing data in a systems context and its preparation for use in such form as to help answer the agriculturists' pe- rennial questions: where, what, how, and when to plant or graze? 2. A review of the relationship between the development of high-yielding varieties and their moisture requirements, with a view to developing cereal grains combining drought- resistance and higher-yielding qualities. 3. A search for simplified forms of systems analysis or critical- path analysis capable of iden- tifying crucial obstacles, needs, niches, and interactions in agri- cultural systems related to broadening the range of drought adjustment. 4. Improvement in the efficiency of irrigation water use. 5. Review and analysis of existing dry-land cultivation methods with a view to improvement and wider dissemination of moisture-conserving tech- niques. Research on climatic and weather systems is designed to provide better forecasts of per- sistence in temperate areas and monsoonal delay in tropical areas. The thrust of these suggestions is in application, to make more use of what is already known through synthesis and systems analysis or simply scientific review, to seek a marked advance through social sci- ence technique in the adoption of what we already know, and to seek selected new knowledge where the gaps in existing knowledge are great or the opportunities seem particularly rewarding. 221 PART VIII AQUATIC ECOSYSTEMS 1. COMPONENT RELATIONSHIPS Trophic Dynamics, with Special Reference to the Great Lakes Trophic dynamics is that kind of ecology which concerns itself with energy flow through the component organisms of an ecosystem. The ul- timate source of energy for any living system is, of course, the sun. Green plants, converting the sun's radiant energy into chemical energy, are said by ecologists to constitute the first trophic level within an ecosystem. All photosynthetic plants, regard- less of systematic affinity, are thus grouped together by ecologists be- cause they all perform this same basic function. Animals that subsist largely by eating green plants constitute the second trophic level, be they aphid or elephant. Their energy source is once-removed from the initial fixation of radiant energy. Although animals of this trophic level are referred to by ecologists as "primary consum- ers," the lay term "herbivore" is of- ten useful. Carnivores that prey largely upon herbivores of any sort constitute the third trophic level. There are usually no more than five trophic levels in an ecosystem because the inevitable loss of energy in the shift from one trophic level to the next higher means that the total energy contained in the bodies of organisms on the fifth trophic level is small relative to the first. This relatively small amount of en- ergy at the top level is disposed into a small number of large and usually widely dispersed bodies, since there is a tendency for the predators at the top levels to be larger than their prey. (See Figure VIII— 1) While the fifth level is often reached in marine ecosystems, in the Great Lakes it is not. Large lake trout feeding upon fish would be the top predators in the open-water com- munity. They operate on the fourth trophic level. Smaller lake trout often subsist largely on small crustacean herbivores; they would be assigned to the third level. Roughly speaking, about half of the living material in a large lake at any one time resides in the tiny cells of the numerous photosynthetic algae — the first level. In lakes as large and deep as the Great Lakes, the overwhelming pre- ponderance of life is found in the open waters — away from the shore and bottom. Yet it is still desirable to refer to this assemblage of life in the open waters as a "community," not an "ecosystem," because the open waters lack full representation of still a different trophic category — "reducers." Reducers is the term ecologists apply to the variety of bacteria and fungi that derive their energy from the complex molecules in the dead bodies and feces of other organisms of the system. Energeti- Figure VIII- 1 — TROPHIC LEVELS The figure illustrates an ecological pyramid showing various trophic levels. The higher the step in the pyramid, the fewer the number of individuals and the larger their size. In some environments, large animals circumvent some of the levels in the food chain. For example, man takes from all levels below himself, including that of the producers. 225 PART VIII — AQUATIC ECOSYSTEMS cally speaking, this biological reduc- tion is excessively wasteful, but the small molecules that result from this degradation can be utilized by the photosynthetic plants, and thus re- enter the trophic levels discussed above. It must be stressed, however, that a not inconsiderable amount of reduction of dead algae and the abundant feces of the animal plank- ton occurs as these sink slowly through the depth of the water. There is thus a recycling of biologi- cally active elements within the water body itself, not dependent upon the seasonal recurrence of full vertical circulation and the cool- season reintroduction of the accu- mulation of the products of reduction on the bottom back into the open- water system of temperate lakes. Contrasting Trophic Dynamics in Terrestrial Systems — Comparison of some of the basic attributes of the open water of a great lake, or of the ocean itself, with those of a well- developed terrestrial system such as a forest reveals some basic dissimilar- ities. The general features of trophic dynamics sketched at the outset ap- ply, of course, with equal validity to terrestrial and aquatic systems. The dissimilarities arise from the differences in the structure of the dominant green plants. Individual producers of the forest attain great size, each striving to spread its photosynthetic apparatus so that it may be fully exposed to the sun, unshaded by its neighbors. The trunk and branches by which each forest tree maintains its leaves in the sun provide, in the aggregate, a rigid three-dimensional framework in relation to which the other or- ganisms of the system dispose them- selves. The leaves are the food source for aphid and caterpillar, sloth and deer, tapir and gorilla. The per- manent woody plexus has made it possible for this variety of sizes of herbivores to evolve, each achieving a different way of exploiting the same food resource but each small in size compared with the green plant, some part of which each consumes. How differently the photosynthetic apparatus is disposed in the Great Lakes! Here the individual plants are tiny — microscopic solitary algal cells or clumps and colonies just vis- ible to the unaided eye (or, when dead or moribund, evident to both eye and nose as floating scum). The principal herbivores in the open wa- ters are small crustaceans, large com- pared to the individual algal cells that constitute their major food, but often too small to cope with large clumps of algal cells. To photosynthesize, the algae must be in the upper, lighted water layers. Under ice, algae are often concen- trated at the very top of the water, but in warm seasons they are swept around in the Langmuir spirals in- duced by the wind moving over the water's surface. When wind is strong and temperature low, the spiral currents may carry the algae too deep for adequate light to pene- trate. But during the warmer half of the year the myriad cells of the phytoplankton are slowly spiralled through the well-lighted, warmer layer of lake water. Quite unlike the forest situation, the green plants of the open water display no semi- permanent, three-dimensional pattern of structure in relation to which ani- mals can orient themselves and evolve special behavior patterns. The open waters provide no place to hide! One reason to stress the differences between these two kinds of commu- nities is that man, the observer, is primatively a member of a forest or grassland community, and some ecol- ogists have too much betrayed their experience of the forest in their in- terpretation of the dynamics of open- water systems. A part of this dif- ficulty of interpretation has been the tendency to expect, in essentially structureless open-water systems, the same kind of fine-grained adjust- ments of organism to environment that have evolved in the substratum- dominated terrestrial systems. Man-Induced Disturbances — The nature of the dynamic model of rela- tionships within the open-water com- munity of the Great Lakes is of more than academic concern. Man has seriously disturbed the biotic prop- erties of these lakes by his multi- farious activities. If the quality of these lakes is to be improved and continuously maintained at an im- proved level, a correct and complete understanding of the ecological inter- relationship is required. The overgrowth of the algae in Lake Erie is probably the most ob- vious manifestation of the disturb- ances that the biological communities of all the lakes have sustained to varying degrees. An algal over- growth, or, in ecologists' terms, an increased standing crop of the phyto- plankton, is a characteristic recent manifestation of lakes in Europe and North America on the shores of which large concentrations of human populations reside. The biological waste produced by the people of cities is biologically reduced, to varying degrees, into small molecules of biologically active elements such as nitrogen and phos- phorus. When these are flushed into lakes directly, or into their tribu- taries, they augment the natural sup- ply of plant nutrients. This "cultural enrichment" of lakes is cumulative. Once the simple com- pounds of nitrogen and phosphorus enter the lake in solution, they are quickly and effectively taken up by the green plants — the phytoplank- ton as well as the rooted water plants along the shore. Henceforth, these elements will reside in the complex molecules of organisms. They spend but little time in solution in the lake water; the amount of nitrogen and phosphorus that will escape through a lake's outlet, dissolved in the water, is remarkably small compared to that 226 COMPONI. ONSHIPS leaving the lake in the tissues of emerging insects or organisms other- wise removed from the lake. Approaches to Quality Management Management of lakes to maintain quality seeks two goals, both of which involve maximizing the rate at which the energy-rich compounds of nitrogen and phosphorus fixed in algae are passed to higher trophic levels. One goal is to reduce the standing crop of phytoplankton, thereby making the water more trans- parent; the second is to find an eco- nomical way to remove nitrogen and phosphorus from the lakes. The third trophic level in the open- water community is the lowest at which nitrogen and phosphorus are concentrated into packets of a size that man can manipulate and use. These "packets" are the bodies of the fish that eat the animal plank- ton; they can be fished from the lake and used directly as human food (as lake whitefish once were in large amounts) or they can be used as a protein source for animal nutri- tion (as alewives can be). We began this discussion of man- generated changes in lakes by sug- gesting that our conception of trophic dynamics within the open water is crucial to attempts to redress some of these biological imbalances. There are two alternate concepts of these relationships (to be sketched below). They differ in their relevance to achieving the two management goals set out above. The more recent for- mulations stress the role of predation by plankton-eating fish in control- ling the species composition of the plant and animal plankton. This con- cept offers hope that the two goals are not only compatible but might be achieved by the same manipula- tions of the system. On the other hand, the older concept — which stresses competition within a trophic level as the prime determinant of plankton composition — presents no simple dynamic model of relation- ships among the first three trophic levels. Attempts at management of disturbed lakes will, therefore, not only hope to achieve practical goals but also to test and extend the con- ceptual models. The Scientific Data Base In general, the data base for evalu- ating and extending knowledge of the trophic dynamic systems of the Great Lakes is inadequate. This dy- namic approach demands knowledge of the interrelationships of the ele- ments of the lake ecosystem, while all that is now available are unre- lated segments of data concerning various aspects of the ecosystem. Data on the seasonal changes in the physical and chemical parameters for more than a few stations at a time in any one lake have become avail- able only within the past decades. Attempts to relate these physico- chemical to biological changes have only been sporadic. Of the biologi- cal data, that on changes in the com- position of the fish stock is probably most nearly adequate. That on the plant and animal plankton, which comprise the bulk of the biomass, is spotty and inadequate. A recently published bibliography of the Great Lakes plankton studies lists over 400 papers, but, as the bibliographer added, The biology and ecology of the plankton remains poorly known. Most papers are descriptive and concentrate heavily on taxonomy and distribution of certain orga- nisms. Experimental work on the dynamics of Great Lakes plankton is urgently needed in light of rap- idly changing environmental con- ditions and fluctuating fish stocks. The last sentence makes the essential point: Significant studies of the trophic dynamics involve simultane- ous studies of physico-chemical pa- rameters, the phytoplankton, the zoo- plankton, the planktivorous fi the piscivores. Various bits of work done recently in Lake Michigan can be put together to provide some insight into the trophic dynamics of that lake. This has provided the reassuring informa- tion that changes in the composition of the animal plankton following changes in stocks of planktivorous fish (establishment of alewives, to be specific) have been precisely what would be predicted from knowledge of the dynamics of much smaller lakes. Furthermore, the time required for the changes to be manifest in the animal plankton of Lake Michigan is not inordinately greater than the time required in smaller lakes. This is not surprising, because the total size of the system should be less significant than the mean ratio of planktivore/zooplankter. Theoretical Formulations: Control from Above A recent theoretical formulation states that the composition of the first trophic levels in the open-water communities of large lakes is deter- mined in large measure by the selec- tive feeding habits of the planktivo- rous fish. The prey selections by the schools of zooplankton-eating fish directly determine the species com- position of the animal plankton. This indirectly affects the quantitative and qualitative composition of the phyto- plankton (algae, bacteria) because species of animal plankton differ in the effectiveness with which their populations can collect algae and other small particles from the lake water. Large crustacean zooplankters of the genus Daphnia play a crucial role in the indirect control of the first trophic level resulting from the selec- tive feeding of the third level. The large Daphnia are both the favorite food of freshwater planktivores and the most effective collectors of small particles (1-50 microns) from the 227 PART VIII — AQUATIC ECOSYSTEMS medium. When planktivore stocks are sufficiently high, the populations of large Daphnia are reduced to in- significant numbers. Since the smaller crustacean competitors that replace them (see Figure VIII-2) are less effective in collecting small algae, the algal populations will tend to in- crease, making the lake water less transparent. This theory, in essence, states that the composition of the open-water community is determined by the trophic actions of the highest (third and fourth) trophic levels. The for- mulation suggests a management concept for controlling the effects of the continued enrichment pollution of the Great Lakes. In essence, the plan would be to reduce planktivore pressure in such a way as to maxi- mize the populations of Daphnia which are most effective in removing algae from suspension. The plank- ton-eating fish could be removed by man through fishing. Removing the fish would remove some "packets" of nitrogen and phosphorus in the lake ecosystem at the same time as it permitted the proliferation of Daph- nia. The fish themselves, depending on their species, could be variously used as human food, animal food, or as a source of oils and other material for chemical manipulation. The stocks of planktivores could also be kept in check by introducing and manipulating stocks of piscivo- rous fish. For example, the introduc- tion of coho salmon into Lake Mich- igan is an attempt at controlling the burgeoning population of the alewife (Alosa pseudoharengus — originally a marine planktivore that, despite its abundance in many freshwater lakes, is still imperfectly adapted to the peculiarities of a freshwater exist- ence). While this method of con- trolling planktivores has the ad- vantage of permitting the nitrogen and phosphorus to be removed in large packets that tend to find greater acceptance as human food, the total amount of these elements that could be extracted from the fourth trophic level of the lake is at most one- seventh of that which could be re- moved via the third. It is thus less satisfactory as a means of decreasing the total amount of nitrogen and phosphorus from a lake than is re- moval of fish from the third (plank- tivore) level. The entire matter of the use of the fish removed from the Great Lakes as food for man or beast has been complicated by the fact that various stable and toxic chlorine- containing compounds such as DDT, DDD, DDE, and PCB's are concen- trated in the oil and body fat of the fish of both trophic levels. Theoretical Formulations: Control from Below In contrast to the concept of con- trol of the composition of the open- water community indicated above, the alternate concept — widely held a decade ago — still has adherents. The control-from-below theory en- visions the composition of the com- munity as being primarily determined by competition within each trophic level. In this view, the composition of the first level — phytoplankton — is determined by the particular con- figuration of physico-chemical con- ditions at the season in question. The species composition of the sec- ond level — zooplankton — is deter- mined primarily by competition among populations of the various species of crustaceans and rotifers that could occur within the lake for the kinds of phytoplankton thriving at that moment. Each species is most effective in collecting only a portion of the total range of sizes and kinds of algae available. The planktivores feed on whichever species of zoo- plankter is available at the time. It can be appreciated, therefore, that changing the intensity of plank- tivore predation upon the zooplank- ton would be expected, by the control-from-below hypothesis, to al- ter the total quantity of zooplank- ton — but not necessarily its specific composition. Since this concept does not consider that planktivore preda- tion has any pronounced effect on the species composition of the zoo- plankton, there is no theoretical basis for attempting to modify the com- position and standing crop of the algae by manipulating the stock of planktivorous fish. Requirements for Scientific Activity Examination of the simultaneous changes in the abundance of all the various species that comprise each trophic level is necessary to evaluate the alternative concepts of trophic- dynamics outlined above. This is an enormous task, even in the Great Lakes where the variety of species on all levels is very much less than it would be in an equal volume of the ocean. The greatest difficulties of enumer- ation and categorization are pre- sented by the extremely numerous small organisms of the plankton. Automatic methods of counting the plankton and categorizing them ac- cording to size must be developed. The Coulter method of counting and sizing particles by the drop in elec- trical potential that each generates while passing through a small aper- ture through which an electric cur- rent passes is not entirely satisfac- tory. This data must be stored electronically so as to be immediately available for use with data on phys- ico-chemical conditions, on the one hand, and data on the characteristics of the fish populations, on the other. In addition to methods of auto- matic data collecting, it will be nec- essary to make provision for the proper taxonomic assignment of spe- cies of the plant and animal plankton. This information, gathered from ali- quots, must be applied to the auto- matically acquired data on size categories. At present this is an operation that is tedious at best and nearly impossible at worst. 228 COMPO\i TIONSHIPS Figure VIII— 2 — EFFECT OF ALEWIVES ON ZOOPLANKTON 15 " 10 1942— WITHOUT ALEWIVES LENGTH 0-4 mm. = Cut Off Epischura \\ Yellow Perch DOMINANT ZOOPLANKTERS Diaptomus Cyclops 16 - 964— WITH ALEWIVES Leptodora 5 mm. Mesocyclops UPPER LIMIT 1.0 DOMINANT ZOOPLANKTERS The histograms show the distribution and composition of crustacean zooplankton (as well as one predatory noncrustacean) before and after a population of Alosa pseudoharengus (alewives) became well established. The arrows indicate the size and the position in the distribution of the smallest mature instar of each dominant species. Such larger zooplankton as Daphnia were present, but they represented less than one percent of the total sample count. The triangles denote the lower limit or cut-off point of the zooplankton consumed by the several species of fish indicated. Note that with the advent of the alewives, the size distribution of the zooplankton was depressed significantly to smaller species. 229 PART VIII — AQUATIC ECOSYSTEMS Seasonal changes as well as natural and man-induced changes in the fish stocks continually perturb the lake ecosystem. Continuous analysis of the perturbations of the plant and animal plankton should make it pos- sible to evaluate the concepts of trophic dynamics, leading to the de- velopment of techniques and concepts necessary for managing the Great Lakes so as to maximize both water quality and fish yield. The primary requirement is the assembly of a scientific staff together with the equipment and instrumenta- tion (ships and collecting gear) nec- essary for collecting extensive sam- ples. The samples should be converted into data as automatically as possi- ble. Taxonomic identification services should be established. Methods for data storage and rapid retrieval should be developed. Much could be done within five years toward the development of effective manage- ment concepts if a concerted effort were made along these lines. Effects of Artificial Disturbances on the Marine Environment The capability of predicting the specific consequence of a general disturbance of a natural community is basic to planning and evaluating environmental controls. Large sums of money and considerable effort could be saved if we could foresee the effects of a particular human activity. History has taught us what to expect from the destruction of forests and prairies. But we cannot now predict, with any confidence, more subtle disturbances or the long-term cosmopolitan consequences of drastic change. This circumstance is rapidly changing. Recent theoretical devel- opments have directed our attention to new ways of looking at the prob- lem. There is reason to believe that it will soon be possible to predict change, at least in relatively simple ecosystems such as exist in the sea. Ecological Generalities Few long-term studies have been made on the changes that occur in natural communities. We must there- fore rely more on theory than ex- perience. It is now recognized that there is a fundamental relationship between the number of species, the number of individuals of any spe- cies, and the stability of the environ- ment. For example, there are fewer species with relatively larger numbers of individuals in severe or unstable environments than in environments whose fluctuations are predictable. If the environment becomes more stable in time, the number of species increases. If the environment is dis- turbed in any way, the number of species decreases. Succession and Regression — Around the turn of this century ecologists recognized that, wherever a land surface was laid bare, it was colonized by species in a regular order. It was possible to predict, on the basis of previous observations, which species of animals and plants would appear first and which would later replace the earliest immigrants. This process of succession of one natural community by another con- tinues until a stable climax commu- nity is reached. However, succession is a reversible process. Any disturb- ance will drive the climax community down to a lower level of succession. The disappearance of species is also in a more or less regular order. If we had data on the changes in all natural communities, we could predict the consequences of a general disturbance using the principle of succession. In the absence of such studies, there may be another way of obtaining relevant data: There is evidence that natural communities are continually responding to local variations in the stability of the en- vironment. Small-scale disturbances drive down part of the system with- out appreciably affecting other areas. If this is the case, a community can be viewed as a temporal mosaic, por- tions of which are at different levels of succession. In this circumstance, the variations in species composition observed in space could be similar to those observed in time. If samples taken throughout a natural commu- nity at one time are placed in order of diversity, the array should simu- late the order of species appearance or disappearance in succession or regression. The Impact of Pollutants At least some of the changes asso- ciated with pollution resemble those observed in natural sequences. For example, the order in which marine species disappear as a sewage outfall is approached is often the reverse of the order in succession. Using this principle, we can take samples throughout an area, arrange them in order of diversity, and predict the changes that would occur in the vicinity of a proposed outfall. Some pollutants and other types of disturbances are probably specific in their effects upon communities, af- fecting some species more than oth- ers. Prediction in these cases will require knowledge of the physiologi- cal responses of particular species to the particular compound or disturb- ance. However, where the disturb- ance is general, as in pollution from domestic sewage or dredging, we should be able to predict the effects upon the community using the kinds of observations and samples now taken by ecologists. Prediction in Shallow-Water Com- munities— Simple communities, low 230 in diversity, are strongly influenced by stresses imposed by the physical environment. Complex communities, high in diversity, tend to be more stable and integrated. It should be easier to predict change in the sim- pler, physically controlled communi- ties than in the complex, biologically controlled associations. Marine communities in shallow water appear to be simpler than those in deep-sea and terrestrial environ- ments. Therefore, the planktonic and benthic marine communities in shal- low water offer the greatest oppor- tunities to test hypotheses concern- ing succession and the relationship between environmental stability and diversity. This is fortunate, since these communities are of great eco- nomic importance and yet suffer the greatest exposure to artificial disturb- ances. If we can perfect methods of prediction in shallow-water commu- nities in the next several years, there will still be time to develop the economic and political institutions needed to prevent the wholesale de- gradation of these important eco- systems. Needed Scientific Activity In the next several years we will need to perform field and laboratory experiments explicitly designed to test the growing body of ecological theory. For the purpose of develop- ing our prediction capability, we should perform such experiments in areas that are undergoing or about to undergo artificial stress. Ecological surveys are now com- monly made in connection with pro- posed reactor installations or sewage outfalls. While such studies vary tremendously in quality, most are worthless. Most are poorly designed without any regard to previous ex- perience or theory. It is not possible to generalize from the data obtained from most of these surveys because of the great differences in the meth- ods of sampling and analysis used. One of the most pressing needs in applied marine ecology is the devel- opment of high and uniform stand- ards for the performance of routine ecological surveys. Monitoring — At the state and na- tional level, it would be highly de- sirable to develop programs to moni- tor environmental events. We could maximize the use of data obtained from the study of artificial disasters if such studies were performed by highly trained teams of observers. High school and college biology teachers might be enlisted in this effort. It would not be difficult to cover the coastlines of highly popu- lated areas such as California. Cen- ters for environmental control could be established to train teams of ob- servers, to develop standards of per- formance, and to collate and analyze data. Such data would be of immeas- urable value in designing basic re- search programs and in developing environmental controls. Research and Training — On a long-term basis, we must continue to support basic research in population dynamics. In shallow-water commu- nities there is a particular need to place more emphasis on larval re- cruitment. Our understanding of the temporal changes in benthic marine communities is severely limited by riONSHIPS our lack of knowledge ecology. It is essential to expand research and training in systematic biology. Systematics remains as the founda- tion of nearly all ecological research. Yet our attempts to attract talent and support in these areas are feeble. The major museums of this country should be the focal points of this effort, but they are suffering decay and neglect. Scientific Preserves — In the long term, it is important to establish large scientific preserves to serve as stand- ards of environmental quality, as natural laboratories, and as sources of larvae for the maintenance of species elsewhere. We must begin this program as soon as possible, for few areas remain suitable for these purposes along our coasts. In conclusion, there is reason to believe that we will have a limited capability of predicting changes in natural communities within the com- ing decade. This capability will be greatly expanded by the rapid devel- opment of ecological theory and the performance of critical experiments in natural communities. To achieve these goals, we should increase basic research in systematic biology and population dynamics, establish scien- tific preserves, and develop programs to monitor environmental events. If we begin now, we may be able to halt the degradation of the marine environment as early as 1990. If we do not begin now, we will reduce the natural communities along our coasts to a level where their contribution to our economy and general welfare will be trivial. Marine Flora and Fauna in the Antarctic The environment of the antarctic seas is less variable than that of temperate latitudes with respect to temperature and salinity, but the quality of light throughout the year may be quite different because of the long periods of light and dark and the winter ice cover. In many parts of the antarctic, especially near the con- tinental margin, the temperature of the ocean water is near 0" cen- tigrade or below, and nowhere in the regions known as "antarctic" — that is, south of the Antarctic Con- vergence— are surface waters warmer than 1.0° centigrade. In deeper water the temperature is almost constantly around —1.8° centigrade. As the Canadian biologist Dunbar has pointed out, a cold constant tempera- ture is not a limiting factor for the 231 PART VIII — AQUATIC ECOSYSTEMS development of life, and the antarctic seas are rich and immensely produc- tive, at least near the surface and at shallow depths. Marine Life of Special Interest to Man Oxygen and nutrients are high in these cold waters, as might be ex- pected from the abundance of life in them. Two centuries ago man drew heavily on the stocks of seals of the sub-antarctic islands; more recently, he has reduced the stocks of blue whales to such low levels that it is no longer economical to pursue them. Recently there have been discus- sions of utilizing the vast populations of the krill, Enphausia superba, which are the principal food of the blue whales, the Adelie penguins, and several kinds of fishes. It is esti- mated that the total populations of krill are equal to all the rest of the fisheries of the world, at least in gross tonnage, or about 60 million metric tons. However, the krill occurs in patches and the small size of the individuals poses difficult processing problems. Also, the animals are "tender" — that is, they must be processed immediately. For these reasons, immediate extensive use of this resource appears unlikely. Among other significantly abundant fishes are representatives of the family Nototheniidae; these are currently being fished on an experimental basis by the Soviet Union. There seems to be less fisheries potential in the shallow-water or sea- bottom life, which is often abundant and varied but lacks the extensive beds of large bivalves found in arctic waters. Large seaweeds are abundant around the sub-antarctic islands and near the shores of the Antarctic Peninsula, and invertebrate popula- tions are large in the vicinity of McMurdo Sound and the Soviet base in the Davis Sea. Most of the as- semblage consists of such organisms as sponges, bryozoa, and echino- derms, of little potential commercial value. The bottom fauna is of con- siderable theoretical interest because of its apparently stable or slowly changing composition, at the same time combined with a diversity of components comparable to that of the Indo-Pacific coral reef environ- ment. The rates of turnover or replace- ment of the antarctic fauna have yet to be worked out in the detail neces- sary for rational harvest of the fish- eries stocks, but the unfortunate his- tory of the blue whale suggests that our relations to the fishery resources of the antarctic will be governed pri- marily by socio-economic rather than ecological considerations. That is, we will simply fish until stocks are so reduced that it becomes unprofitable to expend the effort and funds neces- sary to keep the catch up. Examples of Adaptation The adaptations and peculiarities of the flora and fauna of the shallow waters near the antarctic continent are of great scientific and theoretical interest. Two of the most interesting concern the adaptation of fishes to water that is below freezing by the production of a sort of natural anti- freeze substance (according to one researcher) or to a higher concentra- tion of salt in the blood (according to another); other fish adapt to the low temperature and high oxygen by de- veloping the ability to function with- out hemoglobin. The disagreement between deVries, who finds that cer- tain fishes may resist freezing because of a protein containing carbohydrate in their blood, as contrasted with Smith's observation that this is ef- fected by increased salt, should stim- ulate more intensive and critical work on the blood of antarctic fishes. The adaptations of the Weddell seal, the southernmost mammal, are of particular interest. This animal is capable of diving for periods of more than 40 minutes to depths of 400 meters (about 1,200 feet), can swim under water for at least two miles, and has excellent sense of direction under water. A thorough understand- ing of the physiology of this mammal will help us to understand the prob- lems of diving, which is an increas- ingly significant activity in man's ex- panding use of the sea. Status of Scientific Activity At the present time there is con- siderable interest in the nature and significance of diversity in the sea — that is, whether a high ratio of differ- ences to total numbers of all kinds or abundances is related to a situation that may be in equilibrium or indica- tive of a long-established condition, or whether, conversely, a low pro- portion of different kinds of species indicates recent, temporary, or chang- ing conditions. Many pollution pro- grams are predicated on the idea that diversity may be associated with stable and presumably favorable or optimum conditions. As yet we lack adequate data to ascertain whether or not diversity exists and what it may signify, especially for situations at the bottom of the sea. The benthic environment of the antarctic should provide us with use- ful information on this controversial problem because it appears to be a comparatively unchanging environ- ment with a rich variety of species. The problem will require a more in- tensified level of field ecological work on a year-round basis than is being done at present, at least by U.S. re- searchers. It is in this area that theoretical formulation and mathe- matical modeling (already being at- tempted for situations in other re- gions) would be most appropriate, but we still lack the data base. For example, we are still unable to evalu- ate data concerning diversity in dif- ferent regions of the antarctic. Physiological aspects seem to be much better in hand; a concerted attack on some of these problems is 232 COMPONENT RLI.ATIONSHIPS under way by a group on board the R. V. Alpha Helix. Instrumentation — We are reason- ably well equipped, especially in physiology, to undertake antarctic studies, although details of apparatus can always be refined. One problem that seems to plague divers in partic- ular is the vulnerability of photo- graphic equipment in the cold antarc- tic waters; various kinds of seals continue to break down and put cameras out of commission. We need some functioning under-water photomonitoring systems for the dangerous antarctic waters in order to obtain information under winter conditions near the bases. Manpower — Our principal re- quirement is interested manpower in order to expand field ecolog grams in the next five years b duce data relevant to theoretical ideas in ecology at a scale to keep up with such work elsewhere. Obvi- ously, there is need for some sort of ecological monitoring to help us check on the worldwide deterioration of our environment. In the antarctic, this activity would also provide data of basic and theoretical importance. Systems Approaches to Understanding the Oceans and Marine Productivity The ability of man to affect the biological character of the near shore regions is universally recognized; polluted harbors and lagoons turn blue water to green from enhanced production of algae. Man's ability to add potentially significant quantities of manufactured materials, some of which are biologically active, has been acquired only recently, and rec- ognition of this ability has been startling to scientists and laymen alike. Nevertheless, this unpleasant news is true, with DDT providing the most spectacular and potentially harmful example recognized so far. However, large quantities of an indus- trially useful class of chemical com- pounds, polychlorinated biphenyls (PCB), are also being added to the sea. The DDT experience suggests that the marine ecosystem is highly vul- nerable in two areas: (a) the micro- scopic plants or phytoplankton that form the basis for the biological productivity of the sea, and (b) the reproductive stages of marine ani- mals, beginning with those grazing on the phytoplankton and extending as far as the birds. The phytoplankton, as the green plants of the sea, are intimately in- volved not only with the production of food organisms in the sea but with atmospheric processes as well — for example, the production of oxygen and the absorption of carbon dioxide. The optical qualities of the sea sur- face also are strongly influenced by the amount of phytoplankton pres- ent. Preliminary experiments and ob- servations suggest that the range of sensitivity of marine phytoplankton extends to concentrations as low as one part per billion, coinciding nicely with man's current capacity to add exotic materials to the sea. Figure VIII— 3 illustrates this sensitivity. The role of the ocean as a source of food, especially of protein, and as a means of livelihood for fishermen needs no elaboration. Large-scale changes in the level of production of phytoplankton or in species composi- tion are certain to be reflected rapidly in the populations of fish. Other eco- nomic and health considerations arise in connection with the pollution of the sea near bathing beaches. The Status of Simulation Modeling From the foregoing discussion, the marine ecosystem appears as a com- plex biological system interacting with its immediate physical environ- ment and with the atmosphere. The use of high-speed digital computers in conjunction with simulation models of oceanic productivity and of sub- units such as coastal regions and upwelling areas is now possible; it offers the only real hope of obtain- ing predictive capacity for this im- portant ecosystem. Although the many observations of plant productivity made in the past twenty years have yielded re- liable general patterns, the dynamics of marine production is poorly un- derstood. The simulation model approach has been discovered by biological oceanographers relatively recently, largely as a result of the U.S. effort in the International Bio- logical Program. One interdiscipli- nary group involving meteorologists, physical oceanographers, biological oceanographers, and fisheries experts is engaged in the construction of a series of simulation models of upwell- ing regions, where a disproportion- ately large share of the world's fish- eries resources are located. This group appears to be the only one engaged in a serious program of this nature. The relatively strong field of the- oretical physical oceanography has provided a mathematical basis suf- ficiently sound to enable at least one computer simulation model of the Pacific oceanic circulation to be built, with the result that all known cur- rents appear with approximately the correct transport rates. Such models can provide the necessary hydro- dynamic base for ocean ecosystem models. However, a large part of the theoretical formulation necessary for biological modeling has never been developed to a satisfactory degree. Recently, a considerable amount of productive research has been car- ried out in which the sea is examined from the viewpoint of continuous culture theory, the latter studied in- tensively for industrial and sewage 233 PART VIII — AQUATIC ECOSYSTEMS Figure VIM— 3 — SENSITIVITY OF PHYTOPLANKTON TO INSECTICIDES 100 r- O 0.01 0.1 1 10 100 1.000 INSECTICIDE IN WATER (ppb) The left-hand charts show the uptake of ' 'C by phytoplankton as a function of the concentration of several insecticides. At concentrations greater than one part per billion (ppb) in three of the four species studied, the reaction in uptake is great. The right-hand charts show the effect of adding 100 ppb of DDT and endrin to water containing several types of phytoplankton. The insecticides were added each day for 7 days and solvent was added in equal volume to the controls. The insecticides significantly reduced production in three of the four species under investigation. treatment applications. Through this line of research, some of the results of the intensive activity in biochem- istry and molecular biology are being incorporated into biological oceanog- raphy, and satisfactory calculation models for the absorption of nutri- ents by phytoplankton are being de- veloped rapidly. Since phytoplankton production is limited in most regions of the sea by the rate at which nutrient-rich waters from below are brought to the surface by hydrologi- cal processes, the equations linking phytoplankton production and basic hydrological parameters of the ocean circulation are virtually at hand. From this point on up the food chain, the situation deteriorates. Little useful information exists on rates of grazing by the zooplankton, the small animals intermediate between most fish and phytoplankton. At this level, animal behavior must be taken into consideration and reproduction pat- terns become important. Although general patterns are known, the de- tails remain to be filled in and are largely lacking for modeling pur- poses. The structure and behavior of some fish populations is better known as a result of the pressure of economic value, and simulation mod- els have been developed that are use- ful in the management of specific fisheries. These models, however, are not linked in their present form to the food chain supporting the fishery. Efforts are currently under way to form this link, using the Peru an- chovy fisheries as a basis. In some of the advanced simulation models, the response of fishermen to various regulation regimes is taken into con- sideration. Future Requirements A library of simulation models of oceanic productivity is needed to deal with the problems posed by man's intervention. Some models should be designed to give large- scale coverage without great detail — for example, models of each of the 234 COMP( I \riONSHIPS major oceans. Others are required for specific coastal regions and, fi- nally, for specific estuaries. Within a geographic class, models will be needed for specific purposes in addi- tion to at least one base model pri- marily describing plant-environment effects. The addition of such models to the tools presently available to managerial personnel and policy- makers at the international, national, and local levels could be one of the most important steps to be taken in the near future. Although it is difficult to predict the amount of time required to build these models, some of them should be operational within the next five years. Obviously, the potential dan- gers inherent in an inaccurate or incorrect model are great, and it is absolutely essential that careful con- sideration be given to validation, a step that is almost certainly more dif- ficult than building the model. If the models are to be useful, provisions must be made for collect- ing the required input data. Although it is not usually possible to specify these requirements with accuracy un- til the models are built and running, intelligent guesses can nevertheless be made; and if serious modeling ef- forts emerge, they should be made available to the various environ- mental monitoring programs such as GNEM (Global Network for Environ- mental Monitoring) at an early date. The potential of the simulation mod- els for the detection of anomalous conditions should not be overlooked; perhaps it is not too early to propose the use of simulation models for monitoring to GNEM and other plan- ning groups. Monitoring possibilities are especially attractive at the local level. For example, the deviation of the pattern of the phytoplankton plume produced by a marine sewage outfall from that predicted by a vali- dated model might be used to indi- cate that a toxic compound of a certain class had been introducd into the collection system; the approxi- mate quantity might be indicated as well. The resources for carrying out the necessary research and computer pro- gramming are severely limited at present. However, the progress in simulation modeling made by mete- orologists, especially at N (Na- tional Center for Atmospheric Re- search), is immediately useful, and the interests of young oceanographers and graduate students are highly com- patible with such a program. Given an environment amenable to interdis- ciplinary research, computer facilities, laboratory facilities, ship time, ac- cess to aircraft, etc., the work could be carried out with a good probability of success. Provision for training of students should, of course, be implicit in any such effort, since the intel- ligent use of any successful models will depend on the availability of qualified scientists of very high cal- iber. The highest priority should prob- ably be given to the development of ocean-wide models in view of the potential dangers inherent in the present situation, the virtual impos- sibility of applying any positive cor- rective action, and the long recovery time implied by the nature of the ocean circulation. However, the rap- idly increasing rates of coastal and estuarine pollution call for strong ef- forts in modeling of these systems, too. 235 PART VIII — AQUATIC ECOSYSTEMS 2. OCEANIC PRODUCTION Primary Plant and Animal Life in the World Ocean Aquatic Plants In the sea as well as on land, the primary producers of organic matter are plants. It is estimated that roughly 20 billion metric tons of carbon is fixed by photosynthesis in the sea each year. This amount of carbon fixed annually should not be confused with the total amount of plants, in terms of carbon weight, existing at any one time. Since the process of organic production takes place at a rapid rate in the sea, the average standing crop of plants is a small fraction of the annual produc- tion. This makes a sharp contrast to the plant production on land. The total quantity of terrestrial plants present at any one time is, on the average, much greater than the an- nual production. Potential Use by Man — Another striking difference between oceanic plants and terrestrial plants is in their size and distribution. The vast majority of plants in the sea are microscopic single-cell algae (see Fig- ure VIII— 4) in contrast to the grass, crops, shrubs, and trees that form the bulk of terrestrial vegetation. These small organisms, collectively called phytoplankton, are diffused over vast areas of the ocean. Even the great- est concentrations of phytoplankton, which occur in productive areas at certain times, are nothing compared with the density of plants in green land areas. The enormous expense of collecting these diffused, single-cell organisms from sea water makes har- vesting of marine plants for man's use completely uneconomical. Fur- thermore, many of the dominant spe- cies of phytoplankton have hard siliceous or calcareous skeletons that make them unpalatable to man. For these and many other reasons, the use of phytoplankton as an important source of food appears quite out of the question. There are various seaweeds and other large aquatic plants, some of which are used for food or for man- ufacturing industrial products. Most of them, however, are attached to the bottom and therefore confined to shallow inshore waters. The total yield (in wet weight) of these plants for all purposes from the world ocean is about 900,000 metric tons a year, or approximately 1.5 percent of the total landings of marine fisheries. More than half of this amount is harvested in Japan. Harvesting of large aquatic plants could be increased greatly, but its contribution to the supply of plant food as a whole would be insignificant. The Role of Phytoplankton — The infeasibility of using phytoplankton for food or other purposes does not, of course, affect their basic role in the economy of the sea. Animals can- not manufacture living substance from inorganic materials. They de- rive it directly by grazing on plants or indirectly by eating other animals that have eaten plants. Thus, the amount of carbon fixed by plants (measured by 14C methods) is widely used for evaluating the basic produc- tive capacity of the sea. On a global scale, it may be used for roughly estimating the potential harvest of the sea. Starting with the total fixa- tion of organic carbon and using various assumptions on the efficiency of energy transfer, one can theoreti- cally arrive at estimated harvestable outputs at different levels of the food chain. Estimates obtained by this method vary widely, depending on the assumptions used. Neverthe- less, they indicate a general range within which the potential harvest of the sea should fall, as well as the sources of inaccuracy inherent in this method. It has been demonstrated that, among the areas where intensive ex- ploitation of living resources has been taking place, areas of high primary productivities generally coincide with those of high yields from fisheries. Such primary productivity data by area are useful in a variety of ways. Used in combination with catch stat- istics in heavily exploited areas, they provide means to test the validity of various assumptions on the effici- ency of energy transfer, particularly when data on secondary production (i.e., zooplankton) are also available. They also indicate some of the areas that are grossly underexploited but in which abundant potential re- sources are likely to occur, as is the case with certain parts of the Indian Ocean, the tropical Pacific, and the South Pacific. When such informa- tion is combined with data on the forms of animals likely to be abun- dant in the respective areas, it will provide a substantial scientific basis for planning the exploration and ex- ploitation of such areas in order to extract greater amounts of animal protein material from the sea. Also, the differences in primary produc- tivity between areas are such (1:50) that there are many areas in the world ocean that could be written off, based on productivity data alone, as potential fishing grounds for large- scale industrial operations. Numerous measurements of pri- mary production have been made, but they are largely in the limited areas of the world ocean, and data are quite scarce for most other parts. It would be desirable to incorporate primary production measurements in 236 OCEANIC i HON Figure VIII— 4 — SOME PHYTOPLANKTON (Copyright 1965, Houghton Mitflin Company, Boston, Mass) The illustration shows drawings of some phytoplankton, enlarged about 400 times. Diatoms: 10. Chaetoceros decipiens 11. Ditylium brightwellii 12. Guinardia flaccida 13. Eucampia zoodiacus 14. Thalassiothrix longissima Dinoflagellates: 15. Peridinium depressum 16. Ceratium tripos 17. Ceratium furca 1. 2. 3. 4. 5. 6. 7. 8. 9. Asterionella japonica Rhizosolenia stolterfothii Rhizosolenia alata Grammatophora serpentina Coscinodiscus excentricus Biddulphia regia Biddulphia sinenis Lauderia borealis Skeletonema costatum as many oceanographic programs as possible, with particular a\.l:, paid to the usefulness of such data as a basis for evaluating the relative potentials of food production in dif- ferent parts of the world ocean. Zooplankton Since most oceanic plants are ex- tremely small, the typical forms of marine herbivores are also very small and planktonic, again making a sharp contrast to grazing animals on land. An enormous variety of small crus- taceans and other invertebrates, mixed with the young of larger an- imals including fish, form a commu- nity of herbivores and little carnivores collectively called the zooplankton. Although some species of larger an- imals, such as bivalves, anchovies, and sardines, also utilize phytoplank- ton to varying degrees, the herbivores of the zooplankton, particularly such crustaceans as copepods and euphau- sids, play an overwhelmingly im- portant role in converting plant material into animal material. The size of planktonic herbivores in adult stages ranges from less than one mil- limeter to over five centimeters. They have efficient filtering apparatus to collect phytoplankton. Figure VIII— 5 illustrates some of the zooplankton. Potential Use by Man — Aside from their ecological role as the main grazers in the sea, plankton animals give some promise of being harvested directly by man. Before going into the detail of this aspect, we must explain why man should want to take the trouble of harvest- ing these little animals. As organic matter is transferred from plants to herbivores, from herbivores to first- stage carnivores, and from first-stage carnivores to those of higher stages, there are large losses of energy or materials from respiration and de- composition. The food web in the sea is so complex that we have no simple methods of estimating an average loss at each stage of transfer. For the sake of simplified discus- sions, the efficiency of transfer from 237 PART VIII — AQUATIC ECOSYSTEMS Figure VIII— 5 — SOME ZOOPLANKTON (Copyright 1965. Houghton Miftlin Company, Boston. Mass! The illustration shows drawings of some zooplankton, enlarged about five times. Ostracods: 1. Gigantocypris mulleri: (a) adult with eggs, (b) and (c) two views of young and more transparent specimen 2. Conchoecia ametra 3. Cypridina (Macrocypridina) castanea Copepods: 4. Arietellus insignis, female 5. Gaetanus pileatus, female 6. Euchirella maxima, female one trophic level to the next higher level might be considered to be on the order of 10 percent, the loss being 90 percent. This means that the total production (hence potential yield) of zooplankton is much greater than that of small fishes feeding on zooplankton, and the latter in turn far exceeds that of larger fishes prey- ing on small fishes. Such small fishes as anchovies, sardines, and herring actually make up the bulk of the world's total catch of fish. As the exploitation of living ocean resources becomes more and more intensive, man will sooner or later look into the possibility of utilizing small planktonic animals, the abundance of which is enormous. On a very limited scale, zooplank- ton has been used for many years in some countries of Asia. In Japan, for example, brackish or inshore species of mysids (Anisomysis, Acan- thomysis, and N eomysis) have been used as materials for a traditional food called "tsukudani" and also as feeds for aquaculture. A deep-sea pelagic species of sergestid shrimp (Sergestes lucens), which grows to 40-50 millimeters, has long been processed into dried shrimp. In Southeast Asia (Malaysia, Thailand, Indonesia, and Singapore), shrimp paste manufactured from inshore species of sergestid shrimps, mysids, and other small crustaceans has been a popular food consumed in substan- tial quantities. The total amount of zooplankton now utilized, however, is negligible compared with the amount available in any part of the ocean. For large-scale harvesting of zoo- plankton, certain conditions would have to be met. It would not be economically feasible to harvest zoo- plankton indiscriminately. Harvest- ing must be done in areas where dense concentrations of larger forms of zooplankton occur, and special plankton fisheries must be developed for this purpose. Such concentrations of larger forms are found in many areas at certain times. 238 OCEA EDUCTION The Antarctic Krill — There is general agreement, among scientists, that one of the most realistic targets would be the exploitation of the enormous resources of antarctic eu- phausids (krills), particularly Eu- phausia superba. The species occurs only in the antarctic (i.e., south of the Antarctic Convergence), and is particularly abundant in waters off South Georgia and around Antarc- tica near the edge of the pack-ice. Vertically, it occurs to a depth of several hundred meters at larval stages, but adults are often found in dense concentrations in the surface layer, forming patches of various sizes and shapes. Sexual maturity is reached in about two years, with an average size of 50 millimeters. The krill is the most important food of whalebone whales migrating into the antarctic in the summer; it very often constitutes the entire stomach contents of whalebone whales caught there. Many other an- imals, including seals, birds, and fishes, also depend on the krill for subsistence. (See Figure VIII— 6) Although no reliable measurements are available, the total annual pro- duction of Euphausia superba might be as much as one-half of the total production at the level of herbivores. Based on the estimated amount of the krill eaten by whalebone whales in the antarctic when the whale stocks were large (they have been reduced greatly by overexploitation), the po- tential yield of Euphausia superba, when fully exploited, might be as high as 50 to 100 million metric tons, or roughly equal to the present total fishery yield from the entire world ocean. For some years, the Russians have been conducting experiments in the antarctic to develop methods of catching and processing the krill. They have used large surface trawls and pumps to collect the krill, which have then been processed into meal or paste, and oil. The krill meal has a reasonably high protein concentra- Figure VII 1-6 — AN ANTARCTIC FOOD CHAIN The diagram shows some of the major food chains found in the antarctic. Note that the chain to the whalebone whales is relatively direct; the organic material synthesized by the phytoplankton passes through only one intermediate animal, the krill (Euphausia superba), before becoming transformed into whale flesh. This direct change of plankton is extraordinary and a notable exception to the normally low efficiency of the conversion of organic material from the sea. 239 PART VIII — AQUATIC ECOSYSTEMS tion and the oil is rich in vitamins. The high proportion of unusable chitin (in the shell of the krill) and the rapid spoilage rate present tech- nological problems. But these prob- lems will be solved sooner or later, and the commercial exploitation of the antarctic krill might become a realistic proposition in the future. The Japanese have also shown some interest; research into the exploita- tion of the krill is now part of their national oceanographic program, al- though they have not done very much so far. There are many other areas in the world ocean where large concen- trations of euphausids (of sizes smaller than Euphausia sitperba) are found, but the possibility of exploit- ing them appears even more remote than in the case of the antarctic krill. The California Red Crab — An- other form of zooplankton that has attracted much attention is the Cali- fornia red crab, Pleuroncodes plan- ipes. The animal has a pelagic phase as well as a demersal (bottom- living) phase. The relationships be- tween the two are not well under- stood, although the pelagic phase appears to consist of relatively younger individuals. It is possible that the younger individuals can al- ternate between the two phases. In their pelagic phase, the crabs are capable of grazing on phyto- plankton, particularly larger diatoms. They appear in vast surface con- centrations in waters off Baja Cali- fornia and become an important item in the diet of a variety of predators — birds, tunas, and whales, among others. The red crab in the demersal phase also occurs in dense concen- trations. Two species similar to the Cali- fornia red crab are commercially utilized in Chile, but their concen- trations are found only on the bot- tom. The exploitation of the Califor- nia red crab for manufacturing meal for animal feeds has been suggested by many scientists. No experiments have been conducted, however, to test the commercial feasibility of catching and processing the crabs for this purpose. In summary, the potential of zoo- plankton as a source of animal pro- tein material is great, and man will go into this phase of exploitation of living ocean resources sooner or later. It is obvious that fisheries for zoo- plankton would have to be developed for specific forms of animals in specific areas. However, even for the species that appear most promising, such as the antarctic krill or the California red crab, much more work is needed both in developing the technology of catching and proc- essing and in understanding the ecol- ogy of the species involved, before their commercial exploitation becomes a reality. The Southern Oceans in the Production of Protein The antarctic oceans can be defined for the purposes of this discussion as the region between 60° and 65° S. latitude in the three months of sum- mer: January, February, and March. Such an area subtends 3 million nautical square miles of surface water. During the other nine months of the year, the weather and the extension of sea-ice obliterate this area as ex- ploitable for proteins by man. In- clusion of sub-antarctic waters would triple this area and extend its time of usability at least two months longer: December through April. This discussion involves only ani- mal proteins. There are no sources of plant proteins, unless some may be obtainable from the giant kelp Macrocystis. Protein Sources in the Antarctic Historically, this 3 to 9 million square nautical miles of surface water, and the water-column under the sur- face, have been rich in biomass of animal proteins. The waters in sum- mer have teemed with invertebrates, particularly the relatively small pe- lagic shrimp Euphausia and related genera. There have been many nest- ing birds, particularly on the sub- antarctic islands. Seals have been abundant from the ice-pack north to the sub-antarctic islands and elephant- seals on the sub-antarctic islands. Whales have been, in the past, the most conspicuous form of animal life, and in their abundance have supplied the whaling industry with the bulk of its raw materials, mostly oil, for fifty years, 1910-1960. The supply of whales is practically gone now, however. Fish have been found sporadically in immense shoals, but with such irregularity as to time and place that no fishing industry has grown up in antarctic and sub- antarctic waters. Species of Current Interest — With the demise of the whaling industry — which can return, but only after many years, and which never utilized the animal proteins to the fullest extent — and with the end, in the nineteenth century of the fur-seal- ing and elephant-sealing industry — which could have supplied proteins, but never did, only fur or oil — atten- tion is now being directed toward harvesting euphausid shrimp and 240 PRODUCTION fish. As yet, however, no one is able to predict the success or failure of attempts to exploit these supplies of protein food in southern waters. There have also been some explora- tory harvests of shrimp-seals ("crab- eater seal"), in order to obtain oil and hides and, possibly, meat. The dominant and incredibly abun- dant species of euphausid is the two- inch Euphausia superba, also known as krill. This species often concen- trates in such numbers that it colors the surface reddish and washes up on the decks of ships in heavy seas. It should be possible to harvest great quantities in slow hauls of tine- meshed nets — but what to do with them then? The amount of shell in relation to meat may prevent utilization for human consumption, but the shrimp could be ground into a meal for poul- try. As the shell is "soft," such a ground, dried meal might make a highly satisfactory protein additive to human food. The Soviets are the only group to have made exploratory harvests of Euphausia superba; what success they had or what they did with the shrimp is not clear. Among other invertebrates, there are considerable numbers of giant barnacles, mussels, and stone-crabs in sub-antarctic waters; harvest of these can be increased if transpor- tation to markets improves. None of them is important, however. Seals, particularly the ice-floe seal, or shrimp-seal, Lobodon carcinophaga and the elephant-seal Mirounga leonina are potential protein foods for animal consumption if the entire carcass, except for hide and fat, is ground and frozen in bags of 25 to 50 pounds. Such fresh meat-meal would then include all meat, bones, and entrails, and be nourishing as an additive in poultry food, and as a staple for fur-bearing animals. Populations of the southern fur- seals on sub-antarctic islands are growing steadily, to the point where limited harvest will be possible in a few years without damage to the stock. Here again, after hide and fat are removed and utilized, the entire carcass can be ground and frozen in bags and used as fresh meat-meal for poultry and fur ani- mals. Such controlled exploitation could also include the large southern sea-lion Otaria byroni. Exploitation by Man The Norwegians have already con- ducted postwar sealing in the ant- arctic, principally on the shrimp-seal. Fishing is under exploratory investi- gation now by the United States, by Germany in cooperation with Argen- tina, and probably by the Japanese and Russians. Also, some Chilean fishing boats are now operating out of Punta Arenas in the Strait of Magellan. The results of these investigations seem to have been negative in large yields per unit of effort. But mar- ketable fish have appeared off South Georgia Island in numbers in the past, and these concentrations for- merly gave a good yield to local whalers fishing for their own needs. More exploration might reveal some pattern of availability by species, locality, oceanographic conditions, and season. Whaling has been the only indus- try in antarctic waters, indeed in the entire antarctic area, land or sea, except for the nineteenth-century fur- and elephant-sealing, which was conducted largely on sub-antarctic islands. Whaling started in 1904 at South Georgia Island. From then until the worldwide depression of the early 1930's it grew in volume and geo- graphic coverage to a very high point — too high, as was evident even then, for maintenance of a suf- ficient stock for continued high yield. In the late 1930's, whaling again in- creased greatly. It shui - Hiring World War II, but increa from 1946 to 1960, and it was ous to most concerned people — all except the whaling companies — that the end was not far off. This end almost came in the late 1960's, and now the yield of whales is so low that whaling is conducted by two countries only, the U.S.S.R. and Japan, who harvest mainly the sei- whale, formerly an undesirable spe- cies because of its relatively small size (to 55 feet) and its relatively low yield of oil and meat. Some finbacks are taken, but the few remaining blue and humpback whales are completely protected. There has been some effort by the whaling industry in the past and present, especially by Japan, to save some of the proteins from whales, either in the form of refrigerated fresh meat, meat extract, or meat- meal. But the main product has been oil. The prognosis for whaling in the future is unclear. The industry may continue on a low scale, but surely it cannot grow as long as the popula- tions of fin- and sei-whales are held to low levels. Humpbacks may in- crease to visible and perhaps harvest- able numbers in five to ten years, but whaling from shore stations in lower latitudes on the winter-reproducing herds — same stocks — may then be undertaken. Estimates of the time it will take for the blue whale to recover run as long as fifty years. All whaling should cease for a while to allow even the fin- and sei-whales to recover. They could then yield a fair harvest while the humpback and blue whales also recover. And emphasis should be on meat as well as oil. Signs of Pollution — Contamina- tion of the antarctic waters is not now pronounced, although DDT has been found in the fat of some pen- guins and, perhaps, seals. The prog- nosis for the future is not good, 241 PART VIII — AQUATIC ECOSYSTEMS however, as is also the case with water and land environments for the entire world. In summary, we have the following potential sources of animal proteins in antarctic and sub-antarctic waters: 1. Whales — large source origi- nally, but much depleted by impact of man. 2. Seals — some depleted by im- pact of man, but others not; uncertain source. 3. Fish — not depleted, but uncer- tain as a source. 4. Euphausid shrimp — not de- pleted, and perhaps more abun- dant than before slaughter of whales, but uncertain as a source. 5. Other invertebrates — not de- pleted, but uncertain as a source. Geographic considerations point to utilization of animal proteins from antarctic and sub-antarctic waters by nations of the southern hemisphere — Australia, Chile and Argentina, and South Africa. Perhaps more of South America and Africa can also benefit. Hitherto, most of the oil and other by-products from whales of antarctic waters have gone to the mass of hu- manity in the northern hemispheres. But this need not continue. Scientific Aspects of North Pacific Fisheries The fisheries of the North Pacific have expanded dramatically, particu- larly in the past decade. This expan- sion was the result of increased utilization of the variety of living resources available and exploitation of new grounds (both in a geographic and bathymetric sense). There has been, particularly in the northeastern Pacific, a dramatic increase in yields as a result of Soviet and Japanese fishing operations in the Bering Sea and through the arc of the Gulf of Alaska southward to central Cali- fornia. Figure VIII— 7 shows a map of the world's fisheries. The growth pattern of fisheries in this area, as with many areas of the world, has changed during the past fifteen years. Fisheries may grow to maturity, exceed the productive capacity of the stocks, and collapse in a matter of a few years. Hence, man's utilization of the ocean's bio- logical potential suffers from an in- ability to cope with "pulse-type" fishing activities, lack of an effective organizational structure to implement management systems, and a rather shabby concept of the impact that selective fishing may have on the re- source community. In addition, po- tential interaction of fisheries with other demands on the ocean and its seabed (mineral exploitation, petro- leum, etc.) is not predictable. In summary, the existing prob- lems as they relate to North Pacific fisheries are: (a) how to optimize yields or dollars from what we are now using; (b) how to minimize multiple-use conflicts; (c) how to maintain the productivity of the sys- tem (avoiding degradation and prod- uct contamination); and (d) how to extract the rather extensive under- utilized biological material that in- habits this part of the ocean. Status of Scientific Knowledge Data Base — There is now a fair body of scientific information charac- terizing the fish and shellfish in the North Pacific Ocean. We have a rela- tively good understanding of the geo- graphic and bathymetric distribution patterns of the demersal forms, and we are beginning to have a fairly good grasp of the general magnitude of these resources. The North Pacific pelagic overshelf species are also rela- tively well known, as are their dis- tribution and behavior features. Our understanding of the distribution fea- tures and magnitude of the pelagic oceanic species is far less good. Knowledge of the types, distribution, and abundance of benthic inverte- brates, although far from perfect, is probably adequate to get some gross concept of their potential contribu- tion as food for man. By contrast, our knowledge of pelagic inverte- brates, even in the shallower waters, is quite poor; and we have only a rudimentary understanding of the community, their distribution, abun- dance, and the quantities that might be available as a food supply for mankind. We have fair information on sea- sonal and bathymetric migratory pat- terns for two dozen or more species of fishes in the northeastern Pacific, and perhaps no better in the western Pacific. However, from these data we cannot formulate a general model of the seasonal distribution patterns of biological matter. The specifics of such movement and migration on many species are absent. Our knowl- edge of the factors that influence behavior and gross distributional pat- terns of adults is also rudimentary, and we know even less concerning hydrological parameters that are criti- cal in determining survival of the young. The underlying processes for de- termining year-class strength, cyclic 242 OCEANIC PRODUCTION Figure VII 1—7 — DISTRIBUTION OF THE WORLD'S FISHERIES INDIAN OCEAN ^] COASTAL AREAS— About 50% ol Global Commercial Harvest s.^> UPWELLING AREAS— About 50% ot Global Commercial Harvest _| Less than 1% of Global Commercial Harvest INDIAN OCEAN The map shows the fisheries of the world today. Fish production in the future will depend on the responses of this system to exploitation and on the oppor- tunities that may derive from a better understanding of the system. One critical factor is the total fish production of the oceans, which has recently been estimated to be only four times greater than the 1968 catch, for corresponding species. Another is the vital role played in estuaries and along coastlines, where pollution threatens the nurseries of many commercial species. A third is the role of upwelling. Weather is important to the success of fishing, and further improve- ments in local weather forecasting await a better understanding of larger-scale meteorological phenomena. Altogether, the systems of air, water, and life are intimately interwoven in the production of fishery yields. dominance, and succession in the ocean communities are the subject of considerable rhetoric, most of which is rather fanciful. Hence, we have not been able to get a firm grasp of the relationship between parental stock and subsequent recruitment, nor have we been able to interpret the implications of environmental contamination (degradation) on early life-history phases of marine fauna. Knowledge of the environment that various groups of commercially ex- ploited fish and shellfish inhabit has improved considerably in the past decade, although it is descriptive in character. We can probably state that we now have a fairly firm esti- mate of mortality coefficients (mor- tality, growth rates, etc.) for repre- sentative species that are subject to commercial fishing. It is possible that we can generalize and make fairly good estimates for species for which these coefficients have not been estab- lished. Similarly, we are starting to get a fix on the response of single- species fisheries to the mortality re- sulting from man's exploitation. Limitations — By contrast, how- ever, the existing models are inade- quate to cope with multi-species or 243 PART VIII — AQUATIC ECOSYSTEMS community exploitation. The concept of optimizing yields from single species, although argumentative, is established in principle. But models are not yet available on which to base an aggregate species-management ra- tionale, and we haven't the foggiest idea of the possibilities of exploiting marine fishes on a range-management concept. Finally, although there is a good body of information relating to feeding patterns of fish, the tropho- dynamics, or energetics, of food-chain systems are still poorly understood and are, to a degree, rooted in mythology. Recent Additions to Scientific Knowledge — Considerable new in- formation on the distribution, mag- nitudes, and community aspects of demersal and benthic fishery re- sources has been compiled, particu- larly during the past decade for cer- tain areas of the North Pacific. Important among these are the recent Soviet works (four volumes) which provide life-history data and information on the dynamic aspects of the fish and shellfish resources of the Bering Sea and Gulf of Alaska. These volumes also include new con- tributions as related to benthic com- munities, some new descriptive ocean- ography, and an attempt to establish environmental-resource relationships. In addition, the recent contribution to the understanding of the Kuroshio Current should provide a basis on which to examine its influence on the adjacent fishery resources. The contribution of oceanography to fisheries in the past decade lies largely in describing the environment. This contribution must be tempered, however, by the fact that the de- scriptive features to date are too gross to deal effectively with some prob- lems, particularly those relating to survival of eggs, larvae, and young of species that are commercially utilized. Furthermore, the availability of theoretical formulation, including mathematical modeling, exceeds our empirical capacity to evaluate model- ing forecasts. Needed Scientific Advances The major scientific controversies concerning the North Pacific fisheries relate to (a) the total possible contri- butions of its elements to the food stream, (b) the importance of mari- culture vis-a-vis developing more effi- cient systems to utilize wild stocks, and (c) the character of relation- ships between adult populations and recruitment. Fisheries Management — Among the priorities for scientific advance is the need to develop management concepts and techniques for timely implementation of management. Fish- eries management has been and con- tinues to be largely remedial in character. We need to cope with the problem of pulse-fishing activities, examine it as a theoretical basis for utilizing ocean resources, and find mechanisms that will allow us to forecast trends sufficiently in advance of their manifestation to implement effective management. The concept must cope with managing aggregates as well as single species. The most critical scientific needs as regards management and use of North Pacific fisheries relate to de- riving the nature of the stock recruit- ment relationship, the reaction of multi-species fisheries, the prediction of environmental factors that bring about year-class fluctuations or other- wise influence stock recruitment rela- tionships, and a clear, fundamental understanding of the potential impact of persistent pesticides and other for- eign substances on the productivity of the total ocean food chain, as well as the potential contamination of the food sources. A number of fishery resources in the North Pacific appear to have been overexploited, resulting in loss of food potentials. This seems to have been the product of failure to find an effective means of implement- ing management decisions and the inability of existing monitoring sys- tems to detect important changes in sufficient time to react in a respon- sive manner. Resource Assessment — In addi- tion to the problems of managing exploited resources, there is a real need to evolve the fishing strategy that will allow us to use the full potential in the ocean. This may re- quire considerable information on the behavior patterns of species (a) in the natural state, (b) in response to exist- ing fishing gears, and (c) in response to physical or chemical stimuli that might be used for herding or aggre- gating marine life. One of the shortcomings is tech- nological instrumentation to carry out resource-assessment activities. Most of the classical methods are not really effective for the task. One of the real weaknesses of the data is that they do not provide contemporary infor- mation. The greatest success is likely to come from the development of sonar assessment techniques. Inte- gration of returned echoes, in con- junction with a means of identifying the target, could provide a reliable method for obtaining stock data over wide areas within reasonable costs. Acoustic holography offers some promise of fish identification detected at relatively close ranges. Impact of Pollution — Perhaps the greatest urgency relates to the area of the multiple demands on the ocean's environment. The hazards of pollution in the North Pacific and the potential contamination of the food resources therein are major questions that must be answered in the next decade. We are only beginning to consider the possible implication of man's multi-purpose needs on the ocean's environment. The whole field of pollution — ranging from persist- ent pesticides and other industrial chemicals to oil pollution and the like — obviously represents a danger which is not adequately understood. 244 PRODUCTION These dangers must include potential alteration of the environment as the result of the heat added as a by- product of generating electricity by nuclear means. The whole concept of the ocean's capacity to produce food for man and the technological capacity to use it is a subject of cur- rent discussion. The impact of loss of these resources or inability to de- velop their potential must be consid- ered in evaluating future food sources. We cannot assume that pollution problems will be resolved in time to maintain present biological produc- tion. Indeed, man's multi-purpose needs to use the water environment for transport, to exploit its mineral potential, to develop it for real estate and industrial pur] to use it to dispense his waste products in- crease the likelihood that we may ultimately degrade the general pro- ductivity of the sea. In this respect, the criterion of sublethal level of tol- erance is irrelevant if the accretion of pollutants continues. Time, in this instance, does not possess the infinite quality usually ascribed to it. Some Scientific Problems Associated With Aquatic Mammals The following list of problems as- sociated with aquatic mammals is made up mostly of broad, general problems. There are also many spe- cialized problems, such as diving physiology or the ecology of specific parasites. Pollution Hazards Effect of Pesticides, Petroleum, and Other Pollutants on Marine Mam- mals — The flow of pesticides and other chemical pollutants into the ocean is concentrated in marine mam- mals since they are at the top of the food chain. (See Figure VIII— 8) It is known that chlorinated hydrocarbons are in the tissues of marine mammals in every part of the world. The effect of the chemicals is not at all known. A possibility exists that the apparent high rate of premature births in Cali- fornia sea-lions is related to pollutants. Little is known about the effect of petroleum on marine mammals except that it reduces the insulating capa- bility of fur. This is lethal for sea otters and fur seals in the marine environment and for the furred fresh- water mammals such as otter, mink, muskrat, and beaver. Pollution of the types mentioned is continually increasing. Unless the hazards are understood, marine mam- mal populations can be reduced or lost before the potential effects of the hazard are realized. A variety of sampling experiments and tests with captive animals can be devised to show the effects of the pollutants. Conservation and Management of Stocks Management of World Whale Stocks to Preserve the Species and Restore a Resource — Short-term eco- nomic gain has been the overriding consideration in the exploitation of the large species of whales. Pursuit of this end has resulted in depletion Figure VIII— 8 — THE FATE AND DISTRIBUTION OF MARINE POLLUTANTS POLLUTANT Diluted and dispersed by MARINE ENVIRONMENT Turbulent mixing Ocean currents Uptake by fish Transported by Ocean currents Migrating organisms Concentrated by Biological processes Chemical and physical processes Uptake by phytoplankton Uptake by seaweeds Adsorption Precipitation Invertebrate benthos Zooplankton z Fish and mammals Ion exchange Accumulation on the bottom The diagram shows the various processes that determine the fate and distribution of pollutants in the marine environment. Under favorable conditions, the pollutants are diluted, dispersed, and transported by turbulent mixing, ocean currents, and migrating organisms. Unfortunately, the oceans are not mixed thoroughly and high concentrations of pollutants exist in local areas. In addition, there are biological, chemical, and physical processes taking place that concentrate pollutants and lead the pollution back to man. 245 PART VIII — AQUATIC ECOSYSTEMS of all of the large whales with the possible exception of sperm whales. Sufficient biological and statistical knowledge is now available to put a rational management system into ef- fect. In part, this may have been done. Continued studies are needed, however, to make certain that the quotas already in effect can be sup- ported by the whale stocks (to date, populations of large whales have been measured principally by catch effort) and to help in the establishment of new quotas and regulations. This will require a combination of biological, statistical, and diplomatic effort. International Study and Conserva- tion Agreements on the Ice-Seals of the Bering and Chukchi Seas — The expansion of commercial killing of ice-seals (ribbon-, bearded-, and harbor-seals — ringed-seals are little hunted) by the Soviet Union has resulted in depletion of the ribbon- seal population and has put an added strain on the subsistence living of the Alaska Eskimo. There is a need, agreed to in principle by the United States and the U.S.S.R., for rational harvesting of the ice-seals, arranged by an international agreement. Co- operation between countries increases the effectiveness of data collecting and reduces the effort required of each party. The knowledge needed to manage ice-seal populations is difficult to col- lect. Harvest quotas set on a trial- and-error basis may be used tem- porarily until more data are available. An International Policy on Exploit- ing the Seals of the Antarctic — World whaling and the harp-seal hunting in the North Atlantic yield less and less. As a result, nations such as the U.S.S.R. and Norway have begun to look at the seals of Antarctica as a source of leather and oil. An international policy covering quotas that can be killed, by species and area, is still incompletely formu- lated. Some effort has been devoted toward developing an international plan. This work should be continued even though the basic data for quotas is difficult to assemble and provisional quotas will need to be established at first. The main protection for antarctic seals is the hostile environment. An opportunity thus exists to exploit marine mammal populations in a rational way. The Conservation of Dolphins that are Killed in the Yellow-Fin Tuna In- dustry — The fishermen catching yel- low-fin tuna off Central America with purse seines use schools of dolphins as indicators of tuna. The tuna, for unknown reasons, are under the por- poise schools and follow along with them. The purse seine is set around the dolphins and catches both dol- phins and tuna. (See Figure VIII— 9) Observers estimate that five dolphins are killed for each ton of tuna caught. Fishermen would like to release the dolphins to use again in finding tuna but no effective way of releasing them has been devised. A solution to the problem will require further study of dolphin behavior and experiments in net design. Factors Affecting Distribution Mechanisms Used by Marine Mam- mals to Guide Migration — Some marine mammals make extensive an- nual migrations. A variety of specu- lative suggestions have been made on how the mammals are able to navi- gate regardless of weather conditions and daylight or darkness. In fact, however, little is known about the mechanisms used to guide migration. The process appears to be more so- phisticated than some of the theories might suggest. Discovery of these mechanisms would be of great bio- logical significance and also important in human navigation and communi- cation. The methods of investigation that will explain how accurate navigation over thousands of miles is accom- plished are not well worked out. A combination of approaches will prob- ably be necessary. Relation of Oceanographic Con- ditions to the Distribution of Figure VIII— 9 — A PURSE SEINE Cork Line Lead Line Purse Line Purse Ring & Bridle E Purse Weight Line F Purse Weight Block G Pursing Blocks H Purse Weight or Tom The sketch shows a purse seine being set. The net is placed in the water. The upper edge is kept afloat with buoys, while the lower edge sinks due to weight. The net is drawn around a large volume of water. It is possible to close off the bottom by pulling the net together, thus enclosing any fish within the volume. The entire seine — and all its contents — can then be picked out of the water. 246 OCEANIC PRODUCTION Marine Mammals — Oceanographic strated. Analysis of the accumulating population studies on mammals such conditions apparently have a strong data on ocean conditions can give as the northern fur seal that spends influence on the survival of marine a much better understanding of the many months at sea. Reasons for the mammals, particularly during their ecology of marine mammals than now great variation in survival of year first year. However, satisfactory cor- exists. Unless this can be done an classes cannot be found in the land relations have not yet been demon- impasse may have been reached in environment. 247 PART VIII — AQUATIC ECOSYSTEMS 3. ESTUARIES AND COASTAL ZONES The Relationship of Fisheries to Estuaries, With Special Reference to Puget Sound The total estuarine system of Puget Sound has historically provided food, recreation, and great aesthetic value to increasing numbers of people. Other major uses include shipping and waste disposal. Potential uses may involve oil exploration and drill- ing, utilization of other under-water nonrenewable resources, provision of more land and living space by modifi- cation of shallow water areas, and, of course, a great increase in food pro- duction through development of vari- ous types of aquaculture or even through enlightened manipulation and control of the larger man-made vari- ables. It is the purpose of the follow- ing statement to point out the neces- sity for identifying existing and future goals and problems related to the fisheries of Puget Sound. There is at present no scientific basis for deciding how to optimize the fisheries of Puget Sound while giving, at the same time, full attention to the other existing and potential uses of the estuary. Interaction among the multiple uses of Puget Sound can be expected to be either detrimental or beneficial to the fisheries, but as yet the places and extent of interaction are poorly known, the future signifi- cance of interaction is unpredictable, and therefore the opportunities for planned control are severely limited. Types of Information Needed To achieve a scientific basis for action there must first be an accept- able definition of the goal or goals being sought. That is, what benefits does man expect to realize from an estuarine system: food, recreation, tourism, industry, . . . ? For the pur- pose of this statement it is presumed that viable sport and commercial fisheries (both fish and shellfish) are accepted goals and that they are so strongly desired that any factor which significantly affects them should be identified as fully as possible. Biological — The species of fish comprising the commercial and sport fisheries of Puget Sound are well known, and relatively good catch statistics are available for most of them. We have developed, and are continuing to develop, the capabilities to observe and record changes in fishery populations. Relationships be- tween various species of fish popula- tions, their environment, and the ultimate causes of change, however,' are not well understood at present. For example, what effect does exploi- tation at one trophic level (e.g., her- ring) have on the abundance of fish at a higher level (e.g., salmon)? Pre- dictions of changes in fish popula- tions are still in their infancy and in most cases will remain so until these causes for change are better under- stood. Important questions need an- swers in this area. For example, how does progress in serving industrial and residential development needs af- fect the nursery areas and food-chain organisms that support the desired fish and shellfish species intended for commercial and recreational harvest? Environmental — These are the en- vironmental problems currently af- fecting the fish and shellfish species and their fisheries in Puget Sound: 1. Physical degradation. (a) Marinas, breakwaters, docks, landfills (residential and industrial), log boom- ing, and sawmills. (b) Dredging, rechannelling of river mouths and estuarine areas. (c) Altered river discharge pat- terns due to man's activities. (d) Thermal power sites. 1) Heat discharge. 2) Screening of intake. 3) Use of biocides. 4) Radioactive uptake in food chain. (e) Litter pollution (disposal of garbage and other solid waste). (f) Bio-fouling (which has sometimes made gill nets in Puget Sound totally ineffec- tive). 2. Organic and inorganic degrada- tion. (a) Pulp-mill discharge. (b) Sewage discharge (including detergents and other house- hold wastes). (c) Chemical pollutants (alu- minum refineries, smelters, metal-plating). (d) Petroleum-product pollution (oil refineries and petro- chemical plants). (e) Toxicants from plastics manufacturing. (f) Agricultural wastes; organic and inorganic fertilizers. (g) Siltation and debris from logging activities. 248 ESTUARIES AND COASTAL ZONES 3. Possibilities for beneficial ef- fects from man's activities. (a) Planned addition and dis- persion of nutrients. (b) Selective warming by use of water discharged from power plants. (c) Control of unwanted species by manipulation of appro- priate variables. Political, Social, and Economic — How are diverse value measurements equated for the several benefits that may be derived from an estuary? What is the biological value of clean water? The aesthetic value? What is the value of a recreational fishery? Gaps in Existing Knowledge If the fisheries constitute only one of the values to be realized from an estuary, then satisfactory manage- ment of the entire system cannot be achieved unless there is a means of judging the other values and of expressing the possible interactions to be expected as the renewable and nonrenewable resources are har- vested. Relative values cannot be judged unless there is comprehensive knowledge available about the es- tuary. Descriptive Information — There is an immediate need for more descrip- tive information about Puget Sound. Patterns of water circulation need particular study, including the amount of fresh water in the system, amount and location of runoff, tides, winds, and density differences. Such infor- mation will be indispensable if the fisheries are to be protected from planned and unplanned disposal of waste in Puget Sound. It is entirely possible that the judicious addition of nutrients from domestic and agri- cultural sources might be accom- plished in a manner to enhance the productivity of the fisheries. The extent of nonrenewable resources (oil, sand, aggregate) within Puget Sound should be more fully known. Di- rectly or indirectly, their extraction could have a significant effect on the fisheries. Baseline Studies — To fill another large gap in existing knowledge of Puget Sound, comprehensive baseline studies of present conditions — chemi- cal, physical, and biological — are needed. Man-caused changes can hardly be evaluated unless a norm is known against which the devia- tions may be judged. Time-series studies of physical and chemical fac- tors are required, as well as deter- mination of the amounts and kinds of organisms and appropriate infor- mation on their condition. These basic studies would necessarily deal with each phase of an organism's life cycle in order to uncover, for particular species (e.g., English sole), the requirements while on the spawn- ing grounds, in the planktonic phase, in nursery areas, and as a growing juvenile and adult. It is also vital to learn how much deviation in habitat conditions a fish or shellfish can tolerate and to know the optimum preferred level of each important en- vironmental parameter. The lower trophic levels would also require de- tailed attention, inasmuch as they are indispensable to the continued har- vest of fish and shellfish. Economic Values — Until better economic measures are developed for evaluating the fishery resource, fish and shellfish species more frequently than not will continue to receive relatively low priority when com- pared to other competitive and detri- mental uses of the Puget Sound es- tuary. Figure VIII— 10 presents data for a similar situation in Corpus Christi Bay. Modeling Studies — After suitable data are at hand, a modeling study should be conducted. By this means the organic-matter budget of Puget Sound could be simulated. The prob- able role of organisms as indicators of a changing environment could be studied. Furthermore, a theoretical treatment could be expected to aid in establishing an effective long-term sampling plan and in implementing a reasonably good predictive ability concerning changes in fish popula- tions. Economic values and socio- political considerations must also be used in such a model if all areas of consideration for decisionmakers are to be included. Figure VII 1—1 0 — VALUE OF ECONOMIC ACTIVITIES IN CORPUS CHRIST! BAY Economic activity Dollars per acre per year Biological-aesthetic uses Tourist and local resident expenditure Commercial fishing 152 15 Total biological-aesthetic uses 167 Industrial uses Oil, gas, and shell Cooling water Transportation savings in shipping Effluent disposal savings 130 10 64 1 Total industrial uses 205 Total dollar yield 372 The chart gives an estimate of the dollar value of major activities in Corpus Christi Bay during 1958. No one user was predominant, so no claim could be made for predominant right to use of the bay on economic grounds. Note the small dollar value of commercial fishing and the large value of aesthetic and mining uses. 249 PART VIII — AQUATIC ECOSYSTEMS Acquisition of Needed Information Existing federal, state, and private agencies are fully capable of gather- ing and interpreting all the technical data that may be pertinent to an understanding of fisheries problems as related to the estuarine features of Puget Sound. The accumulation of certain types of basic data can proceed at once; for example, water circulation, life history and ecological studies of selected fish and shellfish, and tolerance of estuarine organisms (including ones at any level of the food chain) to induced environmental changes. But the full range of needed information cannot be anticipated un- til at least a broad definition of the desired goals has been achieved. Pub- lic participation in the selection of goals that are practical for the present and future management of the Puget Sound estuary will necessitate clarifi- cation of the alternative uses of the estuary that are available and their resulting effect on the commercial and recreational fisheries in Puget Sound. Identification of alternative uses of the Puget Sound estuary be- comes, therefore, an immediate and pressing need. Once the needed information for achieving desired goals is at hand, the implementation of recommended ac- tions might well involve federal, state, local, private, and industrial groups. Communication between the involved agencies and groups is indispensable. Concerted action or unified jurisdic- tional authority must be established in order to assure appropriate execu- tion of an adopted plan. A variety of formal and informal schemes are presently used to achieve at least partial coordination between agencies with overlapping authority and re- sponsibilities relating to Puget Sound. A mechanism to guarantee consulta- tion between agencies is needed, as well as a method to provide for reg- ulatory actions that are consistent with respect to accepted objectives. Prospects for Aquaculture As a result of the rapid increase of interest in aquaculture, aquatic biologists and fishery biologists who are familiar with the inshore areas of the oceans have been besieged with questions from industrialists. These questions most often concern the costs of farming and the profit to be realized. Major Considerations There are no simple answers, for the factors involved are more com- plex than they might at first appear to be. A fishery biologist would need to possess the knowledge and skills of a variety of specialists to provide adequate answers. For instance, fish- ery biologists are rarely marketing specialists. They have traditionally been trained to manage populations of fish and shellfish from the stand- point of providing a maximum sus- tainable yield in terms of numbers of fish or weight of fish from a partic- ular exploited stock. Only in recent years have fishery economists pointed out that a vital aspect of managing fisheries is the economic yield. Con- sidering costs to harvest and market value, fishery economists ask at what level of fishing can the maximum economic yield to the fishery be realized. To minimize costs it is often nec- essary to limit fishing effort, since harvesting is carried out by inefficient means because of restrictions on ef- ficient gear or requirements of more vessels and men than are needed to harvest the crop. Information neces- sary to determine the optimum eco- nomic level of harvesting stocks from many fisheries is still unavailable. The biologist is generally ill-pre- pared to present the type of infor- mation that industry is requesting for aquaculture. Unfortunately, the answer is very complicated, involving a host of variables. Species Selection — There are ques- tions the biologist is well qualified to answer, however, such as the feas- ibility of farming a certain few spe- cies. If he is asked about shrimp, for example, he can point out the extent of the available biological knowledge on this species and where difficulties may arise that will be costly to the investors. If asked about other species (for example, spiny lob- ster or the common pompano), he must reply that no one has reared these animals from eggs to adults and that a lot of basic research must be done before that species will be suit- able for farming from a biological standpoint, which is, in turn, many steps and years away from farming at any economically profitable level. Suppose, for example, that larval life of the spiny lobster turns out to last five or six months; then the cost of rearing the lobster through these stages can be so high as to be un- profitable. Furthermore, biological research, like everything else today, is ex- tremely expensive. To obtain what might seem to be answers to simple, straightforward biological questions can be very costly, and even then the answers obtained may pertain only to a certain set of conditions tested in the experiments; under an- other set of circumstances, the biol- ogist might find quite different results from his research. Location — In addition to the selec- tion of a farmable species, potential 250 ESTUARIES ANT AL ZONES profit also depends upon the choice of a suitable geographic area. It is becoming increasingly difficult to find large estuarine areas and water sup- plies that are unpolluted and that provide the necessary requirements for aquaculture. Any hope of estu- arine sea farming in many areas, especially those close to large cities, must be abandoned immediately be- cause suitable areas cannot be found, or, if they are available, are priced prohibitively. Areas away from large cities offer greater hope for aquacul- ture, but the cost of just the land investment can be substantial, espe- cially in sea farming. Feed — Aside from finding suitable locations, a number of other impor- tant aspects can greatly affect fish- farm production and, hence, profits. Feeding, of course, is high on the list. What feeds are required for the farmed species as young and adults is important in the profit equation. Do these feeds provide rapid growth and high survival? Research into nutrition requirements has resulted in foods designed specially for trout and channel catfish in freshwater. But for many of the animals considered for sea farming, biologists are unsure of what foods they consume in nature, let alone what is the most desirable food for these species in captivity. This important quantity in the for- mula must be solved before costs and potential profit from mariculture can be estimated. Manpower and Technology — What sort of personnel are available to operate a sea farm in a particular area bears on the potential profit. Some species require only rather menial tasks; others require skilled personnel or trainable persons. For example, mass rearing of microor- ganisms is a necessity. Again, until answers to these questions can be provided, the amount of profit pos- sible is only speculation. In many areas of aquaculture today technology is moving rapidly, thereby making speculation based on today's tech- niques of little value tomorrow. Market Information — Many re- ports in the past five years or so have produced abundant information on how many fish can be obtained from a certain amount of water in a particular time period. There is little freshwater farming and even less sea farming in the United States at the present time; therefore these fig- ures have been obtained in other areas of the world. Since they give some guidelines as to productivity they are valuable in themselves, but they must be examined carefully. What sort of market exists for the species? In some areas of the world very small fish are an important mar- ket item. In the United States this is not the case. Also, we might ask whether this high production is the result of some unusually fortunate combination of circumstances? For example, when we consider the ex- tremely high production of rafted mussels in the Bay of Vigo (Spain), where three-dimensional water use is practiced, we find that plankton is unusually rich. In some areas of Asia where human and farm sewage is used as fertilizer, production is extraordinary. At this time, in many of the developed countries, there would seem to be little hope of using fertilizers of this kind. It should be added that the time is probably ap- proaching when we will have to util- ize these wastes fully, but in a more sophisticated way, and fish farms are one logical place for doing so. The entire present and potential market for any particular species must be examined with care before the question of potential profit can be answered. This is obviously within the expertise of the market special- ists, not the biologists. The species considered now in the developed countries are those with high market demand and high price. However, if the species can be raised in large quantities, this picture can be altered greatly: they can become a popular consumer item and be available to a larger segment of the consumer population. Also, a number of other species are profitable to raise, but a lot of money would have to be on market promotion before the housewife would consider purchas- ing them. Conservation Laws — The status of conservation laws can greatly affect profit from aquaculture. These must be relaxed to give the farmer com- plete freedom to market any size of fish any time of the year. Put another way, the farmer must not have to try to fit his operation into a scheme of laws supposedly designed to con- serve stocks of wild fish. Two sets of laws concerning the same species should be in effect — one for the fishermen and one for the farmers. Conservation groups place restric- tions on certain times of the year for extended periods. It is during these times that a substantial profit can be realized by sea farmers, who can control their production so that they can harvest at times of peak demand. This is common procedure in the Philippines, where milkfish are harvested during the monsoon season when fishermen cannot fish. In Ja- pan, Fuginaga takes advantage of the great demand for live shrimp during their holiday season in order to ob- tain a premium price for his product. Technology — There are many other important considerations which prevent anyone trained in a particular discipline from being in a position to provide answers to questions con- cerning costs and profits in fish farm- ing. Engineering aspects of building ponds, sealing, and providing the necessary water flow are important facts needed for profitable aquacul- ture. Some corporation research and development personnel are visiting biologists as a means of keeping up on the trends in research and the feasibility of profitable aquaculture. They find that there is only a little commercial fish farming in the United States and that those operations that do exist are on a small scale. Even without the very formidable road- block of the reluctance of private business to disclose costs and profits to would-be competitors, there is no 251 PART VIII — AQUATIC ECOSYSTEMS long history of aquaculture in this country to permit estimates of aver- age cost or average profit. Current Research Activity The larger, more progressive cor- porations are doing more than asking questions of the biologists. They are paying for research on the biological and marketing aspects of aquaculture in order to judge whether their cor- porations should enter into these ventures. Despite the lack of economic data to justify large-scale aquaculture in developed countries, many facts and principles gained from biological re- search and from common sense serve as guidelines for anyone interested in fish farming. The developed coun- tries have the technology to farm their waters efficiently, but they lack the decades of experience that is available in Asia, for example. Aqua- culture in the developed countries must be a profit-making venture, and since markets for many of the species suggested for this are already present, or can be developed with little pro- motion, it would seem that it could indeed be profitable. In the devel- oped countries, too, there has been a boom in oceanic research. A con- siderable share of the results of this scientific research is applicable to mariculture. It is quite obvious that the greatest potential exists for those species that feed low on the food chain, such as some of the crusta- ceans and mollusks. Figure VIII— 11 shows one such scheme. Biologists who are trying to eval- uate the status and near future po- tential of aquaculture recognize that its maximum effort will be in the near shore waters where there is sub- stantial evidence of extremely high fertility. Of course, the matter of ownership and operating costs be- comes more complicated and costly as the distance from shore increases. In at least one United States oyster- farming operation, radar has been used to detect trespassers into leased or owned bottoms who may be help- ing themselves to the ingredients for a stew, from private stock. In Spain, Japan, and the State of Washington, scientists and sea farmers have clearly demonstrated that high oyster pro- duction is possible by using hanging cultures, thereby utilizing all three dimensions of the water. There is no doubt that more use can be made of effluents from electrical power plants, especially at the cooler lati- tudes where ponds or tanks using the warm-water effluent from gener- ating stations can greatly lengthen the growing period of fish and shell- fish. A number of research projects on mariculture are providing much- needed research results. At the Flor- ida Power and Light Company's new power plant, about forty miles south Figure VIII-11 —SCHEME FOR USING SE :WA GE IN AQUACULTURE 4 Detritus (feces pseudo feces) Feeders: sandworms microcrustacea IT 1 Sediment: coarse sand, fine clay, organic Seawater and Nutrients (artificial or sewage) 2 Phytoplankton (natural populations of unialgal cultures) 3 Filter Feeding Herbivores: oysters clams mussels scallops 5 Macroscopic and/or Epiphytic Algae 6 Browsing Herbivores: post larval lobsters, shrimp, and juvenile mullet \ \ / / \ 7 Carnivores: juvenile flounder and striped bass / The diagram summarizes a continuous-flow food chain that may be operated in various permutations and combinations depending on the desired result. The system consists of the following components: (1) Diluted (about 10%) sewage effluent as a growth medium for (2) a continuous culture of natural, mixed phytoplankton. which is harvested at the rate of 50% of the culture per day and passed through (3) suspended cultures (strings or racks) of filter-feeding bivalve mollusks (oysters, clams, mussels, or scallops), the phytoplankton diluted with filtered running seawater and so presented to a sufficient number of mollusks that almost all of the suspended algal cells are removed from the water by the animals. (4) Feces and pseudo-feces produced by the mollusks are deposited on the surface of the sand substrate of the animal culture tanks where this material is fed upon by sandworms, bloodworms, and/or other deposit feeders. (5) Water flowing through the mollusk compartment containing inorganic and organic nutrients regenerated by the animals is passed into an additional chamber containing macroscopic algae and/or epiphytic, filamentous algae which utilize the regenerated nutrients. (6) The epiphytic algae and asso- ciated microbiota serve as food for browsing animals such as juvenile lobsters, shrimp, mullet, or other suitable animals. (7) Although not part of a continuous-flow system, when steady-state equilibrium conditions are reached, animals from any of the above compartments may be fed to carnivores (juvenile striped bass, flounder, and lobsters are examples of readily available species) on a daily-ration basis, the success of this stage being dependent upon the operation of a large enough system to provide a constant supply of food over a sufficiently long period of time to the carnivores. 252 ESTUARIES AND COASTAL ZONES of the University of Miami's Institute of Marine Sciences, researchers are developing techniques to rear pink shrimp. There are seven ponds, which range from one-quarter acre to one acre, and a hatchery building wherein the stock is raised from egg to adult through the difficult larval stages. The questions that research- ers are asking is whether it is pos- sible to mass-produce pink shrimp with high survival and rapid growth rates on an economic basis, what is the best food for these shrimp, and what are the costs for food and labor. This research began a year or two ago, and progress has been grati- fying. Large numbers of young, es- timated at about 10,000, have been reared from the egg. Shrimp are also being raised to market size in ponds and fenced-off portions of a bay by a newly formed company, near Panama City, Florida. In this operation, between 10 and 20 million brown shrimp have been reared from the egg to post-larval stages. In a number of National Marine Fisheries Service Laboratories (St. Petersburg Beach, Fla.; Oxford, Md.; Milford, Conn.; Panama City, Fla.; and Galveston, Tex.), research on mariculture beneficial to industry is being carried out. At state universi- ties on the Gulf of Mexico and up the east coast of the United States, re- search is also being conducted on desirable species to provide industry with baseline information to allow them to carry out commercial opera- tions in sea farming. At the University of Miami's In- stitute of Marine Sciences, a graduate student has succeeded in rearing thir- teen species of marine fish up to their juvenile stages from eggs caught drifting in the sea. Sea trout and flounder are included in the list and should attract the attention of sea farmers. There is high hope for increased study of aquaculture, but much more research and investment will be nec- essary before the important answers are available for making decisions on the economic advisability of entering aquaculture on a large scale. 253 PART VIII — AQUATIC ECOSYSTEMS 4. DYNAMICS OF LAKES Lake Circulation Patterns Lakes are large bodies of water which would he mostly stagnant ex- cept for the "stirring" influence of wind on their upper surface. In rare cases, lakes are part of a river system and the flow of water through them drives a pattern of circulation, while small heated ponds can have their own thermally induced circulations. In most other lakes, however, includ- ing the North American Great Lakes, wind stress is the prime mover of any "circulation" (i.e., more or less or- ganized motions) and "mixing" (i.e., random motions leading to the dis- persal of an admixture). Man uses lakes for several pur- poses. Most important, perhaps, is the "aesthetic" use (building a house on a lakeshore), closely coupled to a "recreational" use (swimming, boating, etc.); lakes are also used as a source of food (fisheries), of fresh water supply, as a sink for waste materials (sewage), and for waste heat (power generation). Some lakes also serve as waterways. These uses conflict to some degree, and optimizing the use of, say, the Great Lakes is not a simple problem. For example, in many places around the Great Lakes, the only present alterna- tive to using the lakes as a waste-heat sink for power generation is to build cooling towers, which would increase the costs of power generation quite appreciably. At the same time, it is not certain whether or how far the discharge of large quantities of warm water into the Great Lakes would have undesirable consequences for some other use of these lakes. Conflicts between different lake uses are alleviated by lake "circula- tion" and "mixing." For example, none of the Great Lakes is in any sense "polluted" as a whole at pres- ent, although the water near the shores certainly is in many places. The difficulty is that the pollution is usually concentrated in an "in- fluence zone" near an effluent source, which is usually located at the shore. If all waste matter and waste heat discharged into a lake were mixed with its entire body of water, there would be far less interference with other lake uses — although there are clearly limits to the advantage to be obtained in this manner. The main cause of circulation and mixing in most lakes is the stress that the wind exerts at the air-water interface. The actual patterns of cir- culation are also determined by the shapes of the basins, the thermal (density) structure of the water, and, for large lakes, the rotation of the earth. The problem is basically one of physical oceanography (or physical "limnology," to be precise, although the behavior of lakes is usually dis- cussed in the oceanographic litera- ture). However, heat by solar radia- tion, evaporation heat loss (both af- fecting density structure), and wind stress are inputs the knowledge of which comes from meteorology. Evaluation of Current Knowledge Generally speaking, problems of a meteorological nature are better ex- plored than those of the oceano- graphic kind. Most existing knowl- edge on physical limnology was developed in connection with bio- logical studies, witness the highly authoritative Treatise on Limnology by Hutchinson. Indeed, several emi- nent workers in physical limnology started their careers as biological limnologists. Inevitably, then, the character of existing knowledge re- flects a certain bias toward problems of biological importance. For ex- ample, the annual cycle of tempera- ture distribution in lakes (which has a direct bearing on life processes) is well explored, while the dynamics of medium- and large-scale motions is poorly understood. "Meteorological inputs" are also better known. While it would be a gross exaggeration to say that the problem of predicting wind stress over a water surface is solved, we can make a much closer estimate of this stress than of the speed of the current produced by it. Wind Mixing — In greater detail, the "wind mixing" of the top layers of lakes, their yearly cycle of "over- turn," and similar "local" phenomena are fairly well documented, even if the basic mechanics of these processes (e.g., the formation of steep "steps" in the thermocline) are only now be- ginning to be investigated. Inspiring fundamental work in this area has recently been reported from the Med- iterranean and the Great Lakes and from laboratory simulation. These studies have been complemented by results obtained through computer modeling in connection with the nu- merical forecasting of ocean circula- tion. The small-scale structure of turbulence, of internal waves, their "breaking" and interaction with tur- bulence (leading to vertical mixing, particularly across the thermocline) are highly relevant to the mixing problem and are under investigation in a few places. Wave-Like Motions — Among the large-scale motions in lakes, the best understood are the "seiches," or regu- lar surface oscillations, usually started by bursts of wind. Perhaps the most prominent example is provided by the seiches in Lake Erie, which acquire economic importance due to their effect on the output of the Niagara power plant. 254 DYNAMICS OF LAKES Internal waves and seiches of large scale often play an important role in the circulation of moderate to large lakes. In the Great Lakes, it has re- cently been demonstrated that in- ternal waves dominate the flow regime during summer in the central portions of the lakes — i.e., away from the shore zones. It is generally assumed that the energy of these large internal waves is degraded into smaller-scale motions that produce mixing. But there is a complete ab- sence of information on how this degradation takes place; as a result, we don't know on what days to ex- pect or not to expect "good" vertical or horizontal mixing. Another completely obscure aspect of internal waves is the mass trans- port they cause. Individual particles execute back-and-forth motions in waves, often over a period close to 17 hours, but there is also a residual or "transport" motion on top of the wave-induced movements. The latter determines the bulk motion of any admixture to the lake, and next to nothing is known about it (in con- trast to actual, instantaneous current velocities, which have been measured frequently and in many places). In- deed, lack of information on mass transport in a flow regime dominated by wave-line motions (particularly in- ternal waves) may be said to be the greatest single "gap" in knowledge concerning circulation problems in lakes, particularly in the Great Lakes. Currents — Persistent currents are usually weak in lakes, including the Great Lakes, with the possible excep- tion of Lake Ontario, wherein the Niagara River plume may perhaps be classed a "current." Apart from this, the possibility exists that long, slow internal waves of the "Kelvin" type produce fairly concentrated currents with a lifetime of at least several days. Recent work has indicated the ex- istence of such quasi-permanent cur- rents near the shores of some of the Great Lakes, but the evidence is far from conclusive. Observed currents at moored stations in the shore zone of the Great Lakes show a greater degree of persistence than in the cen- tral portions of the lakes, but the spatial and temporal current structure is too complex to allow reliable gen- eralizations at present. Indeed, one of the main conclusions one may draw from recent work on coastal currents is that the details are too complex, and an experimental technique aimed at the determination of bulk mass transport in the shore zones (some appropriate tracer technique, for ex- ample) should provide more useful information than further direct cur- rent measurements, requiring the de- ployment of a large number of meters. Another important point is that current structure around the shores of the Great Lakes is different from place to place as well as from season to season — yet we know little about current or mass transport "cli- matology" even though this is most important in connection with the use of the lakes by man. Some turbulent diffusion experi- ments have been carried out in the Great Lakes recently, simulating sew- age outfall and warm effluent dis- charges. The data are mainly relevant to an initial phase of dilution (just after leaving the discharge), and even in this connection it is not certain that the diffusive properties deter- mined would be similar to those in other locations, where the current structure may be radically different. On large-scale mixing, data are quite scant, but what information there is appears to show that any effluents discharged in the shore zone tend to remain there for several days (a phenomenon termed "coastal entrap- ment"). Indeed, it is not at all clear what the physical mechanisms are by which coastal waters mix with the main body of the lake. There is little or no direct informa- tion on the connection between cer- tain conspicuous thermal features of the lakes (upwellings, the "thermal bar" during the warm-up period) and any current structures that may be associated with them. However, theory suggests that some strong cur- rents may accompany marked ther- mal features of this kind. It is also obvious that a sudden appearance or disappearance of upwelling along a shore has an influence on the water exchange between the shore zone and main lake mass. (See Figure VIII- 12) Similarly, the fate of heated effluent may be very different from that of effluent with no thermal effects, because warmer and lighter water may "slide out" over the rest of the lake and assume a flat lens-like shape. Such phenomena are known to occur in rivers and estuaries but no detailed observations in lakes seem to be available. Modeling and Instrumentation Mathematical modeling of circula- tion and mixing in lakes (specifically the Great Lakes, or at any rate lakes large enough for the rotation of the earth to be important in their dy- namics) is in its infancy, but some good first steps have been taken in the past twenty years or so. Numeri- cal modeling on the lines suggested by atmospheric work should be com- paratively easy (a two- or a three- layer model should be adequate), the main problem being to display the multitude of results in an intelligible form. It should be added, however, that no mathematical modeling has so far even been suggested for the main variable of practical interest, the total mass transport in the shore zone (due to currents and wave-like motions). The instrumentation available for experimental work in physical limnol- ogy has not kept pace with modern developments in other fields of sci- ence. One agency reported that it had a 40 percent useful return rate from its own moored current meters during the 1969 summer season — a completely unacceptable situation which is nevertheless quite universal. Available current meters are not suf- ficiently sensitive at low speeds; they 255 PART VIII — AQUATIC ECOSYSTEMS Figure VIII-12 — UPWELLING OF COASTAL LAKE WATERS ^ WIND ^ (1) »- -► »~ (3) > v V V V V J ? \ \ V O f V V ^ <> NEGLIGIBLE FLOW (4) 20- 40- 60- WINDERMERE NORTHERN BASIN 26 OCT. 1949 The circulation and upwelling produced by the stress of a steady wind on a small lake is shown hypothetically in sketches (1) to (3). In diagram (4) the actual thermal distribution is shown after 12 hours of wind stress. At the upwind end of the basin, the thermocline intersects the water surface. are not at all accurate in a wave zone. An important recent addition to in- strumentation has been the airborne infrared thermometer, which should be exploited more systematically in the future. Apart from this instru- ment and the fluorometer used in diffusion studies, we are still relying on crude, ancient devices quite un- worthy of the Space Age. Scientific Recommendations A most encouraging recent devel- opment is that many fluid dynami- cists previously in aerospace research are turning their attention to lake dynamics. This should be encour- aged to the fullest possible extent. The full understanding of the basic dynamics of lake motions (where di- rect effects of turbulence are un- important) should be well within the reach of fluid dynamicists today, and should also provide important in- sight into the somewhat less manage- able problem of ocean dynamics. Further, studies of internal zoaves and turbulence (including their interac- tion) also promise to be fruitful for the understanding of mixing proc- esses, particularly mixing through stable layers. At the same time, knowledge so gained is also relevant to certain atmospheric problems, no- tably to the understanding of clear air turbulence. Experimental studies of internal waves and turbulence are more easily done in a lake than 30,000 feet up in the atmosphere. From a practical point of view, the greatest urgency attaches to coastal- zone studies of mass transport, cur- rents, and diffusion. Present knowl- edge in this field is quite inadequate for even the crudest engineering de- cisions. For example, the cooling- water system for a large power plant next to one of the Great Lakes was designed on the basis of an under- estimate of "typical" current speeds by an order of magnitude; as a result, the cooling water in that plant now frequently recirculates from outlet to intake, raising the cooling-water tem- 256 OF LAKES perature, with deleterious effects on efficiency. Immediate and systematic work is required on the climatology of coastal currents at various loca- tions and in various seasons. Also, it is necessary to conduct a long series of large-scale diffusion experi- ments to define the likely "influence zones" of potential effluent outlets, again as a function of location around lakes, particularly the Great Lakes. Given the present dearth of knowl- edge, it would take perhaps ten years of concentrated effort to achieve some sort of consensus on the most urgent topics (climatology of currents and influence zones) that affect the most important of our lakes, the Grea' Lakes. It may take 25 years to build up a solid enough base of funda- mental knowledge (dynamics of cur- rents, mass transport, internal waves, turbulence, and mixing) for the con- struction of more detailed prediction models for long-term planning and "resource management." The Effects of Thermal Input on Lake Michigan Our concern for the environmental quality of the Great Lakes arises from their relatively closed condition. The lakes serve as channels for internal navigation, as highways to the world's oceans, as sources of water for cities and industries, including electric power, as recreational re- sources — and as sinks for the water- borne wastes from urban and agri- cultural land. As the multiple uses increase, problems appear. In spite of its large volume and generally good water quality, some parts of Lake Michigan — for example, south- ern Green Bay and some harbors near Chicago — are becoming grossly polluted; this is a development that the public is not prepared to tolerate any longer. The threat to environ- mental quality is a direct consequence of the multiple uses to which the lakes are put and of the rapid rise of population over the last century, particularly in the southern half of the region. With present agricultural practice and systems of waste disposal, the Great Lakes — whether we like it or not — are the receptacles of waste products of all kinds, some of them long-lived. They are becoming over- loaded beyond their natural capacity, in some places intolerably so. Is this an inevitable consequence of a large, highly industrialized civilization with a high standard of living? It need not be so, if we are willing to pay the price in regulatory planning and in dollars to maintain reasonable stand- ards of water quality and to work with nature rather than against it. It should be noted that water quality remains high in the northern part of Lake Michigan and in Lake Superior. This represents a national treasure that must be conserved and wisely managed for posterity. Heat Dissipation Projected to 1990 One form of waste is waste heat. This particular use of Lake Michi- gan's waters is expected to grow rapidly with growing power demands by industry and by home-owners and institutions seeking to improve their interior environments (e.g., through airconditioning). The question is whether the price we pay for this must include biological deterioration of the lake. It is perhaps not generally realized that some of the largest generating plants in the country already use Lake Michigan for cooling. The 1970 col- umn in Figure VIII— 13 indicates that the equivalent of 16,000 megawatts is added to the lake in the form of heat at present. According to a fore- cast by the Argonne National Labo- ratory, this figure is expected to be nearly doubled by 1975, when further large units (many of them nuclear generating stations) now under con- struction or being planned come into operation. Beyond that, projections of the increase are largely guesswork, but must presumably bear some re- lation to the projected rise in national demand, forecast as doubling every ten years up to 1990. If this demand is to be met, it will be done with larger units, mainly nuclear, and these need large heat sinks to operate at maximum efficiency. There are only three heat sinks with sufficient capacity: the ocean, the atmosphere, or (for the Midwest) the Great Lakes. The interest of power companies in Lake Michigan is, therefore, not sur- prising. Effect on the Lake Even allowing for improvements in thermal efficiency, heat dissipations from Lake Michigan for 1970, 1980, and 1990 are likely to increase at a rate that slightly more than doubles every ten years. (See Figure VIII-13) If these estimates are accepted as rea- sonable, we may calculate the orders of magnitude of the effect on the lake. This has been done in three ways in Figure VIII-13. A typical daily total of heat input from the sun in early summer is 300 of the units used in the figures (gram-calories per square centimeter of lake surface). The daily total heat output from power stations in 1990 is less than one percent of this, if spread over the whole lake surface. But this is, of course, unrealistic, bearing in mind that all the heat is injected near shore. 257 PART VIII — AQUATIC ECOSYSTEMS Figure VIII— 13 — THERMAL INFLUENCE OF ELECTRIC POWER GENERATION ON LAKE MICHIGAN 1970 1975 1980 1990 Power to be dissipated, in units of 1000 megawatts, as heat 16 28 37 75 Equivalent daily heat input, g-calories per cm2 of: (i) whole lake surface (ii) inshore strip (depth less than 10 m = 33 ft.) 0.57 7 1.0 12.5 1.3 16 2.6 33* Equivalent temperature rise °C, assuming a 10-day storage and complete mixing into: (i) whole lake volume (ii) inshore strip (depth less than 10 m = 33 ft.) 0.0007 0.14 0.0012 0.25 0.0016 0.33 0.0032 0.66 Equivalent evaporation increase as decrease in lake level (cm per annum), assuming all heat lost through evaporation 0.34 0.62 0.81 1.63J * 5-10% of a summer day's natural heat input into the t equals 1/20 ft., about 2% of natural evaporation, i.e., inshore strip. less than the annual variability. The table shows estimates of the effect of heat input into Lake Michigan due to waste heat from the generation of electric power. These effects are indicated in terms of an increase in lake temperature and an increase in evaporation. If we consider only the inshore strip of water (of depth less than 10 meters, or 33 feet), which covers 8 percent of the lake area, the picture looks different. In that case, the daily total input of heat from power stations for every day of the year by 1990 would be about 10 percent of the sun's input on a summer day. Temperature Rise — Another way of looking at the matter is to con- sider the temperature rise of the whole or part of the lake attributable to power-station inputs. This is a much more complicated and uncer- tain calculation, because of lack of knowledge of the rate of dispersion and of how long the heat stays in the lake before it is lost to the atmos- phere, or to space by back-radiation, or to increased evaporation. This re- tention time is a statistical estimate in any case; it is certainly greater than one day and probably less than 30, so a guess at 10 days seems not unreasonable. With that guess we find, again, that the effect on the whole volume of the lake is negligible but that the effect on an inshore water strip is appreciable. For ex- ample, the temperature rise of the inshore strip, based on these assump- tions (10-day storage and complete mixing into this inshore volume), would amount to 0.7 centigrade — i.e., a little over 1° Farenheit by 1990. These estimates do not, of course, take into account any major engi- neering changes or advances in de- sign leading to better thermal effi- ciency. The significant conclusion from this is that, because the heat input takes place at a number of point sources, there will be measurable temperature rises locally but the aver- age effect on the whole lake will not be substantial. It is with local effects, then, that we must be concerned. Natural Phenomena — The natural temperature regime of the coastal water is complex. In summer, there is sporadic upwelling of cold bottom water, depending on the stress of the wind over the whole lake, coupled with the effects of the earth's rota- tion. The temperature at near shore intakes (for example municipal water plants) can sometimes change by many degrees in an hour. Another phenomenon that adds to the complexity of coastal circulation, and which is not this time dependent on changes in the wind, is the so- called thermal bar. This is most marked in spring, when the shallow water near shore is warming up to temperatures above that of maximum density (4"C), while the offshore waters remain at their winter tem- perature below 4° centigrade. Where the warmer inshore and colder off- shore waters mix, a water mass is formed close to the temperature of maximum density. This mixture is heavier than the original inshore and offshore water masses from which it was formed, and it therefore sinks. This continually sinking water mass (a convergence) forms a temporary barrier to horizontal mixing between inshore and offshore waters. At the same time, the convergence is a rather efficient way of carrying water (and, therefore, heat) from the surface into the deeper regions of the lake. As the spring heating continues, the thermal bar migrates further and further offshore until, usually some time in June, the summer thermal stratification is established right across the lake. At times when the thermal bar is strongly established, water may be trapped inshore for several days or weeks. The effect of thermal discharges into that trapped water mass is a matter for conjecture. But it seems likely that situations 258 DYNAMICS OF LAKES could arise, at least on particular days in the year, when the thermal plume from an electric power station would travel along the shore for a long dis- tance with relatively little dilution, rather as a plume from a smokestack is visible for miles when there is a temperature inversion in the atmos- phere. Evaporation — Although we have emphasized the local, near shore ef- fects and minimized those offshore, there is one whole-lake consequence of larger thermal additions. This emerges when we consider the final fate of the added heat. A large part of it will be used in increasing evapo- ration above the natural level, al- though some will, of course, be lost by back-radiation and heat exchange with the atmosphere. If we make the worst assumption, from the point of view of water con- servation, that all the heat is lost through increased evaporation, the estimated power dissipation in Figure VIII— 13 can be translated directly into water loss. Tabulated as centimeters of water lost from the whole lake sur- face per year, the loss rises to 1.63 centimeters, or about l/20th of a foot, in 1990. Integrated over the whole lake surface, this is an impres- sive volume and, in fact, represents about 2 percent of the mean outflow of Lake Michigan, which is 46,000 cubic feet per second, and about 2 percent of the estimated annual na- tural evaporation. Some of this will, of course, be returned to the lake by later precipitation. It should be noted that the proportion of heat (and therefore water) lost through evapo- ration would be greater if cooling towers were used. Needed Research We need to be able to predict the local thermal effects with more pre- cision and, in particular, to study the way in which the hot plume disperses, paying particular attention to rates of diffusion. In Lake Michigan this should be much more than an engi- neering study through physical or numerical models. It should also in- clude an in-lake hydrographic study, because the current regime and conse- quent diffusion in the lake itself varies greatly. And we need to ex- amine not only the average long- term circulation patterns, but also the fluctuating circulation patterns asso- ciated with such temporary phenom- ena as upwelling, internal waves, and thermal bars. There are a number of mechanisms that sometimes tend to keep water near shore for days or weeks. This is not to say that the lake is not well mixed at other times; indeed, at least once a year, in Janu- ary, it is probably very thoroughly stirred. But we must also consider the consequences of rare types of cir- culation with minimal diffusion — for example, under extreme thermal-bar conditions — which may develop per- haps once every ten years. And then, of course, there are pos- sible biological effects. We clearly need surveys to identify biologically sensitive areas. We could learn much by carrying out some of these surveys near existing large fossil-fueled sta- tions. These have been operating for years, but no one seems to have re- ported major deleterious effects on Lake Michigan. We should certainly look and see if there are any; we should also try to differentiate be- tween true thermal effects and those arising from material wastes, looking also for interactions, harmful or bene- ficial, between thermal discharges and more conventional pollution. At the same time, there should be a thorough search of the literature. There is a large body of published material, including that from Atomic Energy Commission (AEC) labora- tories or AEC-supported work, on the effect of radioactive materials and thermal discharges on organisms. The public is clearly thirsting for knowledge on this subject, and anno- tated bibliographies would be most useful. We hear a great deal of loose talk about the harmful effects of radioactive and thern; urges, so we should at least know what has been done before we decide which research gaps need filling. Special studies should be made in the biological field. These should be concerned with concentration effects, already mentioned, and with the in- fluences to which aquatic organisms are subjected in a fluid in which, while the levels of radioactivity may be very low, they spend the whole of their lives. Engineers and others should be encouraged to collaborate in pilot studies leading to the beneficial use of waste beat. A number of ex- ploratory projects are already under way: irrigation of fruit orchards to avoid frost damage; fish culture; raising the efficiency of other waste- disposal systems. Finally, we come to planning and to the value judgments that planning entails. There is a great need for over-all regional planning, for ex- ample to decide on the siting of new nuclear power stations. They must avoid biologically sensitive areas (e.g., fish breeding grounds), they should not be grouped to aggravate the thermal effects, and if possible they should be placed where they could be useful. If, for example, waste heat could be used to keep the St. Lawrence Seaway open for a few more weeks in winter, that would permit overseas shipping lines to make one more run per year to the Great Lakes — a tangible benefit. With competent and imaginative research and planning and with in- telligent siting of power stations, it should be possible to enjoy the bene- fits of nuclear power without threat to other users or to our enjoyment of the Great Lakes. The research should include not only the study of near shore water circulation and the ecological consequences of the temperature rise, but also advanced engineering leading to beneficial uses of the waste heat. Design and plan- 259 PART VIII — AQUATIC ECOSYSTEMS ning must seek a high rate of heat last point has perhaps not been suf- generation. In view of the tendency dispersal by turbulence, avoid bio- ficiently stressed. Power stations will to build larger and larger stations logically lethal high temperatures, have a permanence and remain a away from population centers, it can prohibit construction in biologically safety responsibility far beyond the be argued that the threat to the sensitive areas (to be identified), and short design life of the reactors. They landscape is greater than the threat preserve landscape amenities. The will be monuments to our present to the lake. 260 5. LAKE EUTROPHICATION AND PRODUCTIV Fishery Deterioration in the Great Lakes Before human settlement, the wa- ters of the Great Lakes abounded in fish characteristic of large lakes with cold, clear water. But the fish popu- lations and the environment of the Great Lakes have undergone pro- gressive deterioration for more than a century. Degradation has acceler- ated at an alarming rate in recent years. Valuable fish such as Atlantic salmon, lake trout, whitefish, blue pike, and walleye comprised 80 to 90 percent of the production of the early fishery; but in recent years these species have contributed less than 5 percent of the catch from the lakes in which they are still present. (See Figure VIII-14) The Great Lakes, 64 percent of which lie within U.S. boundaries, cover 95,000 square miles and are the largest and most valuable fresh- water resource in the world. The fish populations constitute the great- est and most valuable renewable re- source of the lakes. Peak U.S. fishery production occurred around 1900, when 100 to 120 million pounds of mostly high-value species were taken annually. The catch subsequently de- clined. In 1963, it reached a low of less than 53 million pounds — com- posed primarily of medium- and low- value species (alewives, carp, chubs, perch, sheepshead, smelt, and suck- ers). Causative Factors Until recently, the causative fac- tors of this drastic change have been a subject of great controversy. It is now known that modifications of the drainage by agriculture, urbanization, and industrialization, and intensive, selective fishing for the most valuable species have caused major changes that led to invasions of new species and deterioration of water quality. The exact ways in which these in- fluences have affected individual spe- cies or groups of species are not yet completely understood. Careful re- view of the entire sequence of events within the Great Lakes and their drainage, however, is providing in- formation essential to the formula- tion of environmental criteria and elaboration of management plans that can be implemented to reverse undesirable trends and restore much of the value of the Great Lakes and their fisheries. Settlement of the Lake Ontario basin and the construction of the Erie and Welland canals were the events that initiated a chain reaction that has now upset the ecological balance of fish populations through- out the Great Lakes. As noted, Lake Ontario and the St. Lawrence River were once inhabited by an abundance of cold-water species dominated by the Atlantic salmon. Early accounts describe how the cutting of the for- ests and agricultural development increased water temperatures and lowered flows of streams in which Atlantic salmon spawned. Mill dams blocked spawning streams. Disposal of mill wastes in streams, as well as intensive fishing, also contributed to a sharp decline of Atlantic salmon during the mid-1800's. The salmon were scarce by 1880 and extinct by 1900. Repeated at- tempts to re-establish them have Figure VIII-14 — COMMERCIAL FISH CATCH: LAKE MICHIGAN 100 60 O o 40 - O 30 - LAKE TROUT - LAKE HERRING SUCKERS--/ / -" WHITEFISH / - YELLOW PERCH -^V/ £ s\ CHUBS / /-— — ^ carp ^-^\^y =— SMELT /"""^ -/"" ALEWIFE 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1898- 1910- 1909 1919 1920- 1930- 1935- 1940- 1945- 1950- 1955- 1960 1961 1962 1963 1964 1965 1966 1929 1934 1939 1944 1949 1954 1959 The diagram shows statistics of the commercial fish catch on Lake Michigan from 1898 to 1966. The degradation of the fish population is clearly evident; although the total catch returned to turn-of-the-century levels in 1966, almost all of it consisted of alewives and other low-value species. 261 PART VIII — AQUATIC ECOSYSTEMS failed. Even though a salmon fishery no longer existed and the problems of mill dams and pollution had been eliminated in most streams, the lower flows and warmer waters continued, indicating that removal of timber and agricultural development within the drainage had created conditions that made the region unsuitable for survival of the Atlantic salmon. Effects of Marine Invaders — Elim- ination of the Atlantic salmon, which was the major fish predator of Lake Ontario, created conditions favorable for the entrance of the alewife, which was the first and most de- structive marine invader. As the sal- mon were declining, the alewife was entering the Lake Ontario drainage via the Hudson River and the Erie Canal. By 1868, alewives had be- come abundant in the Canal and in the Finger Lakes, which drain into Lake Ontario. Large schools of small alewives were reported in Lake On- tario in 1873 — by which time the Atlantic salmon had been reduced greatly. The lake trout was another major fish predator in Lake Ontario, but it, too, was declining during this period, possibly due to heavy ex- ploitation. More recent experience in the other Great Lakes has shown that the small, landlocked alewives are unable to thrive when any of the Great Lakes is densely populated by larger fish predators. Without predators, how- ever, the alewife in Lake Ontario was able to increase rapidly; it had become the most abundant fish by 1880. Furthermore, by 1900, the ale- wife had greatly reduced or virtually eliminated all of the previously abun- dant small species of Lake Ontario that depended on plankton during at least part of their lives; as past studies have shown, the alewife has a strong competitive advantage over native freshwater fish that also feed on zooplankton. The alewife used the lake much less efficiently than native species, causing a reduction in the total amount of fish in the lake. The previously abundant native species had occupied all zones of the lake during the entire year. In contrast, the alewife ranged throughout the lake in dense schools but occupied different portions of the lake in vari- ous seasons; under its dominance, the vast deep-water region repre- senting 70 to 80 percent of the area of the lake was unoccupied by other species during most of the year. The parasitic sea lamprey was the second marine invader of the Great Lakes. It had free access to Lake Ontario via the St. Lawrence River but it did not become established in Lake Ontario until the 1880's. Con- ditions that made the lake unfavor- able for the Atlantic salmon appar- ently made it suitable for the sea lamprey. The inland ranges of the two species do not overlap — the Atlantic salmon favors drainages that have durable, cool streams suitable for its fall spawning, while the spring-spawning sea lamprey favors streams that become warm following the spring runoff. Once the Atlantic salmon, which fed on small fish, was eliminated, the sea lamprey, which feeds on large fish, became the dominant pred- ator; once established in Lake On- tario, it prevented any sustained re- surgence of lake trout, whitefish, or larger species of deep-water ciscoes (commonly called chubs by fisher- men of the Great Lakes). Thus, the combined effect of the invasions of the alewife and the sea lamprey was to reduce drastically the fishery pro- ductivity of Lake Ontario. If it were not for the Welland Canal, which provides a waterway that bypasses Niagara Falls and al- lows access to the upper lakes, the destructiveness of these marine in- vaders would have been limited to Lake Ontario. Both the sea lamprey and the alewife were able to nego- tiate the Welland Canal, however. The sea lamprey reached Lake Erie by 1921, was established in Lake Huron in 1932, Lake Michigan in 1936, and Lake Superior in 1946. The alewife first appeared in Lake Erie in 1931, Lake Huron in 1933, Lake Michigan in 1949, and Lake Superior in 1954. Neither the sea lamprey nor the alewife became a severe problem in Lake Erie, which had few suitable spawning streams for the lamprey and had substantial populations of predators to keep alewife abundance low. Conditions in Lakes Huron, Mich- igan, and Superior favored the lam- prey and alewives, however, and these lakes were to suffer fates sim- ilar to that of Lake Ontario. The influences of the lamprey and alewife occurred in the reverse order. As the lamprey became established in each of the upper lakes, it destroyed the lake trout that was the major fish predator of the upper Great Lakes. Loss of the lake trout was followed by establishment and rapid increase of the alewife population. In Lakes Michigan and Huron, the destruc- tion of large fish by the sea lamprey and small fish by the alewife became as severe as in Lake Ontario. Development of a chemical method of sea-lamprey control was first ap- plied in Lake Superior and prevented the complete collapse of the lake- trout population that had occurred in Lakes Michigan and Huron. Al- though present control methods have not been sufficient to permit restora- tion of significant spawning stocks of lake trout in Lake Superior, sus- tained introductions of hatchery- reared trout have held the alewife in check. The status of Lake Superior re- mains uncertain, however, as sea lam- preys are thriving; the sparser popu- lations resulting from the control measures have enabled the lamprey to reproduce more prolifically than ever. The remnant lamprey pop- ulations pose a serious threat to rehabilitation of a reproducing popu- 262 LAKE EUTROPHICATICN AND PRODUCTIVITY lation of lake trout and to the abun- dance of other large native species ■ — whitefish, lake herring, and larger deep-water ciscoes — as well as to the recently introduced coho and chinook salmon. In summary, the invasion of ma- rine species made possible by eco- logical disruption during settlement of the Lake Ontario basin in the 1800's has been a major contributing factor to substantial reduction of the fishery productivity of Lakes On- tario, Huron, and Michigan, and the ultimate effects on Lake Superior are still uncertain. Effects of Deteriorating Water Quality — The most serious threat to the biological stability and fishery productivity of the Great Lakes has been a progressive deterioration of water quality. During early settle- ment within the Great Lakes drain- age, organic pollution characteristic of nonindustrialized society fouled tributaries of the Great Lakes; it had virtually eliminated populations of river-run lake trout, whitefish, lake herring, walleye, yellow perch, and sturgeon by the late 1800's and early 1900's. These populations made up a major segment of the total fish stocks in the lakes and they have never recovered. More recently, there has been in- creasing evidence that a much more ominous type of pollution has ac- companied advanced industrializa- tion. This "new" pollution consists of discharges of complex chemical and physical wastes from advanced industrial, agricultural, and urban ac- tivities, and from massive releases of heated waste water from industries and power-generating plants. The combined effects of the "con- ventional" and "new" environmental contaminants cannot be described or their influences on aquatic life ex- plained by existing criteria or meth- ods. The mechanisms of their in- fluence on aquatic life are unknown, but the fact that they have had major detrimental effects on aquatic life is beyond question. Southern Green Bay, Saginaw Bay, Lake St. Clair, the Detroit River, and all of Lakes Erie and Ontario are polluted to the extent that they have lost virtually all of the "clean water" species that were once abundant in them. The sequence in which fish declined or disappeared and water quality deteriorated has been the same in all areas. The lake trout declined first, followed by lake her- ring, whitefish, sauger, blue pike, walleye, and yellow perch. The deep- water ciscoes are very sensitive to environmental degradation, but they decline late in the sequence because the deep waters are influenced later than shallow areas by contamination. Lakes Erie and Ontario have been the most seriously affected by pol- lution. These were the two most productive Great Lakes. The species of fish characteristic of large northern lakes were once extremely abundant in both lakes, but all are now greatly reduced, rare, or extinct. Since Lake Erie was not influenced greatly by the invasions of the alewife and sea lamprey, the loss of its valu- able species can be attributed pri- marily to the complex, yet poorly understood, effects on aquatic life of massive introductions of biological, chemical, and physical wastes of an advanced industrialized society. Lake Erie still has large populations of fish. Sheepshead, carp, and goldfish, which have little present value or use, abound in the lake and its bays. Present biological information shows, however, that populations of the more valuable walleye, yellow perch, and smelt appear to be in imminent danger of collapse. Fishery produc- tivity of the large central basin of Lake Erie has been reduced greatly in recent years by oxygen depletion in the bottom waters, which has made a major portion of the lake uninhabit- able by fish or fish-food organisms. The fish populations of Lake On- tario have been affected more se- riously than any other Kike. Early reductions of fish stocks due to in- fluences of the alewife and sea lam- prey have been compounded in recent years by additional reductions caused by the extreme deterioration of water quality in Lake Ontario, which is the ultimate recipient of all wastes entering both Lakes Erie and On- tario. The vast deep-water region of Lake Ontario is devoid of any valu- able and abundant species of fish. The native species that supported the most productive and prosperous fish- eries of the Great Lakes during the early and mid-lSOO's have all become greatly reduced or rare; many are extinct. The native species lost in Lake Ontario due to water-quality degra- dation — lake trout, whitefish, lake herring, deep-water ciscoes, deep- water sculpin — are the only kinds of fish that thrive in any of the large, deep lakes of the world. If the water quality of Lake Ontario cannot be restored so that it is again favorable for these species, the lake's fishery potential will be lost forever. If the water quality of the other deep lakes — Michigan, Huron, and Supe- rior — continues to deteriorate, their vast deep-water regions will also become fishery deserts. Status of the Environmental Science Development of an understanding of the precise causes of the biological degradation of the Great Lakes is in the formative stages, and is advanc- ing slowly in a few scattered problem areas. Existing techniques and gen- eral knowledge of present and poten- tial problems seem adequate to for- mulate a systems approach that could, when sufficient monitoring and research information become avail- able, describe and predict the biologi- cal interactions in the Great Lakes environment and relate biological re- sponses to activities of man in the lake basins. 263 PART VIII — AQUATIC ECOSYSTEMS A few cause-effect relations of en- vironmental degradation are under- stood — e.g., the cause of oxygen depletion in Lake Erie and its relation to the disappearance of blue pike and the diminution of other fish and fish-food organisms in the region of the lake affected. The relation be- tween excessive phosphorus and ob- noxious algae blooms in Lakes Erie, Ontario, and other scattered locations has been established. Lake Ontario is no longer suitable for lake trout because the clean, rocky spawning areas essential for its reproduction are covered by a fibrous mat. Studies of the effects of chemical and physical factors on biological productivity and stability are in pre- liminary stages for a few species. Some information is being obtained on the physical requirements for suc- cessful incubation and hatching of the alewife, the sea lamprey, and some species of the whitefish family. Thermal stresses and physiological responses that influence alewife die- off and abundance are under study. Problems of species interaction are incompletely understood and only a few are subject to adequate study at present. Information on selective feeding of the alewife and the result- ant effects on changes in the com- position of fish-food organisms gives clues to possible competitive advan- tages of the alewife that may explain the decline of various species when the alewife becomes dominant. There is some evidence that more complex feeding interactions and competition during certain life stages of smelt, deep-water ciscoes, and lake herring may have contributed to the sharp reduction of lake herring in certain areas of Lake Superior in the absence of alewives. The ability of the un- checked sea-lamprey populations to destroy a lake-trout population by eliminating all mature trout has been documented by detailed studies in Lake Michigan, but the relation be- tween lamprey-attack mortality of lake trout and other large native spe- cies is not known. Thus, the degree of lamprey reduction that will be required to restore substantial stocks of large species, as a step toward restoration of a favorable balance of all fish species, is still uncertain. Also unknown or uncertain are the relations of physical, chemical, and biological change to the declines of native species throughout the Great Lakes. These are the species or kinds of species that must be rehabilitated to restore the fishery productivity of the Great Lakes. To prevent dete- rioration of the lakes from pro- gressing to the point where biological and fishery restoration may be ex- tremely difficult or impossible, control of environmental degradation and un- desirable species must be undertaken before research on cause-effect rela- tions of the various factors of de- gradation can be completed. Never- theless, the research must be initiated expeditiously and pursued vigorously. The Need for Monitoring — A ba- sic requirement for research to gain a full understanding of the fishery environmental deterioration of the Great Lakes is a comprehensive moni- toring program to measure all aspects of the chemical, physical, and biologi- cal environment. The present data base and existing instrumentation and techniques are adequate to start development of a suitable monitoring system. Data from monitoring are needed to provide measures of the long-term trends and the frequency, intensity, and duration of short-term fluctuations in environmental factors. Particular attention should be given to physical and chemical contami- nants, and the measurement of changes in the composition and biomass of biological components of the environment. Meaningful moni- toring will require a full understand- ing of the sources and identity of all physical, chemical, and biological contaminants entering the lake. Research Questions — Environ- mental monitoring and the sources and identity of contaminants will provide the data that are needed to give clues for cause-effect relations that can be investigated by specific field and laboratory studies. What factors contribute to failure of hatch- ing or early survival of the previously abundant native species that must be restored? Precisely how might certain chemicals, such as pesticides and heavy metals, influence the physiol- ogy, behavior, reproductive process, or survival of various species of fish? What effects would massive releases of thermal wastes in various locations and by various methods have on eggs, fry, young, and adult fish, and fish-food organisms, in different sea- sons? These questions must be an- swered to provide suitable guidelines for maintaining the biological stabil- ity and productivity that might be achieved after the present environ- mental degradation has been halted and reversed in the most seriously affected lakes. Even under very stringent protec- tion, the Great Lakes will continue to be influenced by growing urbaniza- tion and industrialization within the drainage. These influences will un- doubtedly cause some uncontrollable changes (physical and chemical con- tamination, directly or indirectly re- lated to pollution or modification of the atmosphere) and accelerated en- richment. Change may continue to be too rapid for biological processes to accommodate to it. Thus, research will be required to determine the rate of change that can be tolerated and still maintain biological stability and fishery productivity in the Great Lakes. This information will be es- sential for possible future modifica- tion of the initial guidelines and standards that must be enforced im- mediately to "save" the Great Lakes. Need for Increased Understanding and Action It has been said that, for the aquatic ecologist, fish are the miner's canary. The reason why some spe- cies have disappeared is unknown, but deterioration of water quality 264 LAKE EUTROPHICATION AND PRODUCTIVITY that has an adverse influence on fish may signal a trend that could soon have detrimental effects on other life dependent on water, including hu- mans. Restoration of the Great Lakes for fish should also restore their value for all other uses. The essential measures that must be taken from the environmental standpoint to restore the lakes that have been severely damaged (Erie and Ontario) and reverse deteriora- tion of the others (Michigan, Huron, and Superior) are clear. The attack must be basin-wide, must be initiated expeditiously, and pursued vigor- ously. The plan must include: (a) improvement of land uses within the drainages that have direct or indirect influences on the lakes and their tributaries; (b) elimination of sources of physical, chemical, or biological pollution entering the lakes directly or indirectly; and (c) restoration of favorable and productive fish popula- tions within the lakes. Restoration of Environmental Con- ditions — Improvements within the drainage basin of the Great Lakes will require extensive restoration of vegetation and forests that were de- stroyed by wasteful land practices of the past century. This will improve the water quality and increase the stability of the flow of tributaries entering the lakes. Land-use prac- tices, both urban and domestic, must be modified and closely regulated to prevent toxic substances (pesti- cides and others) and fertilizers from entering the runoff of the drainages. (See Figure VIII— 15) No practice should be allowed that would influ- ence streams or rivers biologically, physically, or chemically in such a way that water conditions would be- come less favorable than those that might be expected from natural runoff. The most crucial problem of lake restoration is the elimination of all sources and kinds of pollution that enter the lakes. Any treated effluents or domestic and industrial wastes that are permitted to enter the lakes must be of equal or better quality than the waters in the lakes they enter. Effluent from waste treatment that cannot meet these standards should, after being treated to the highest degree possible, be diverted into drainages outside the Great Lakes basin. These effluents would be of higher quality than the water of rivers into which they would be diverted; thus, the practice of divert- ing them from the Great Lakes would have the dual benefit of preventing degradation of the Great Lakes and improving the water flow and quality in rivers of the north and central United States. Costs of water treatment (partic- ularly for industrial wastes) might be reduced greatly by the construction of inland waterways wherever feas- ible to permit reuse of water and provide channels for the diversion of treated waste waters from the Great Lakes basin. A number of proposals for the construction of such channels in the Great Lakes and central U.S. regions have already been made. It may, in fact, be neces- sary to divert excess water from the Great Lakes region to irrigate the arid south-central sections of the United States before the end of this decade. Present collective drainage- disposal systems are a move in this direction; but, unfortunately, they are not being planned to fit a basin- wide system and will probably have to be modified or rebuilt at great cost before the century ends. Figure VIII— 15 — THE EFFECT OF FERTILIZER ON NITRATE CONCENTRATIONS IN RIVERS 80 1 1 1 i 1 1 1 1 1 1 1 • 1945-1950 KASKASKIA ICKfi-lQfiA K/^KASKIA 1 70 - O 1945-1950 SKILLET FORK 1946-1961 SKILLET FORK — 60 - 50 - 40 - 30 - /- 20 10 n • • • i i T • O 1 * \ / ^, — - • _^_V* •. 1 1 1 1 1 1 i - 0\. U.S. HEALTH LIMIT J J Months The graph shows the difference in nitrate concentrations between two rivers in Illinois — the Kaskaskia River, which drains a heavily fertilized farming area, and the Skillet Fork River, which drains an area where little fertilizer is applied. The threefold increase in nitrate concentration for the Kaskaskia River between 1945-1950 and 1956-1968 follows the increased use of industrially fixed nitrogen fertilizers. 265 PART VIII — AQUATIC ECOSYSTEMS Release of heated waste water into the Great Lakes should not be per- mitted until studies have shown that the previously abundant native spe- cies will not be adversely affected. The only fish that can thrive in lakes the size of the Great Lakes are cold- water species, and all spend portions of their life cycle either near the shore or the surface of the lakes. Fish in the larval and juvenile life stages are the ones that usually live near shore or the surface and would be most sensitive to the influence of heat wastes in these regions. Their presence in these regions would be mostly during late winter to early summer, when thermal gradients would be the sharpest and possibil- ities of detrimental effects the great- est. Restoration of Fish Stocks — Cur- rent with restoration of more fa- vorable environmental conditions, steps must be taken to restore more favorable stocks. Sea-lamprey control now being conducted in Lakes Supe- rior, Michigan, and Huron must be intensified and extended to Lakes Ontario and Erie. Measures to reduce alewives should be intensified by introduction of large predators such as lake trout and salmon and by exploitation where necessary. The most critical requirement, while re- ducing alewife populations, is a con- current restoration of the small native forage species. This transition will require several decades and will re- quire careful measurement and close regulation of the kinds and amounts of fish introduced or removed from the lakes. Successful restoration of fish in Lakes Erie and Ontario will require sufficient improvement of water qual- ity to permit establishment of pre- viously abundant species. Control of sea lampreys and reduction of alewives in Lake Ontario should re- verse deterioration of fish stocks as water quality is improved. Restora- tion of Lake Erie will require the development of some method to re- duce the extreme abundance of sheepshead in the open lake and carp in the shallow areas to create condi- tions favorable for return of more desirable species. Present Urgency The need for immediate action to restore the environmental quality, biological stability, and fisheries of the Great Lakes cannot be stressed too strongly. At present, Erie and Ontario are the only lakes that have been measurably affected by water- quality deterioration throughout the entire lakes. One of the largest rivers in the world — the St. Clair-Detroit River system — flows through these lakes, and the water entering this river system from Lake Huron is still of high quality. Erie and Ontario are the smallest of the Great Lakes and have flushing rates (ratio of lake volume to volume of annual inflow) of approximately 3 and 8 years, re- spectively. Thus, if all wastes are prevented from entering Lakes Erie and Ontario, there should be initial improvement of water quality within 5 to 10 years and significant improve- ment of water quality and aquatic life within 20 years. The most urgent need, however, is to stop the environmental deteriora- tion of Lake Michigan. Degradation of Lake Michigan has approached the point that biological processes are being adversely affected. Once dis- rupted, it may not be possible to re- store the fishery productivity of Lake Michigan. Even with complete re- moval of all wastes from effluents entering the lake, or diversion of all effluents from the basin, the water from natural runoff into Lake Mich- igan would be richer than water within the lake. Consequently, Lake Michigan could not be flushed or "cleaned." (The only possibility for flushing Lake Michigan would be to divert a large quantity of water from Lake Superior and introduce it at the southern end of Lake Mich- igan.) The deterioration of Lake Michigan would hasten the deteriora- tion of Lake Huron. If this should occur, the present source of "clean water" essential for the restoration (flushing) of Lakes Erie and Ontario would be eliminated. Policy Requirements The techniques and instrumenta- tion are available and there is a cadre of scientific personnel knowledgeable about the broad biological problems and requirements for their solution on the Great Lakes. There is, how- ever, no U.S. organization with the specific mission or clear responsibility to conduct the studies or establish the guidelines that are necessary to assure the biological stability or maintenance of the over-all fishery productivity of the Great Lakes, other fresh water, or estuarine wa- ters of the United States. Also, the facilities are lacking for necessary further study. There is also no pro- vision in the scattered existing moni- toring systems for the comprehensive coverage of all physical and chemical parameters that would be required for biological studies, and biological and fishery monitoring are minimal in some areas and lacking in most areas. The Great Lakes are a national and international resource and must be managed as a complete system. There is no federal agency or com- bination thereof that can assume full U.S. responsibility, nor are there in- ternational agreements that can guar- antee full and effective joint interna- tional action. Of the several agencies and commissions with responsibilities concerning the Great Lakes, the Great Lakes Fishery Laboratory (U.S. Department of the Interior) and the Great Lakes Fishery Commission (U.S. -Canada compact) have the broadest experience and delegations of responsibility for studies and the greatest capacity to make recom- mendations concerning environmental quality — particularly concerning problems related to biological degra- dation and fishery resources. 266 LAKE EUTROPHICATION AND PRODUCTIVITY The Great Lakes Fishery Labora- tory has made evaluations of envi- ronmental quality and fishery re- sponses to environmental change ever since it was established in 1927. Its present laboratory facility and four research vessels constitute the great- est U.S. capability to provide guide- lines and criteria for Great Lakes fishery and environmental restora- tion. At present, however, its efforts are limited to partial studies on cer- tain sections of Lakes Superior, Mich- igan, and Erie, with token attention to Lakes Huron and Ontario. Resto- ration of the Great Lakes environ- ment will require full attention to all lakes, and will need much more than the present effort by the Great Lakes Fishery Laboratory and the fragmen- tary efforts of other U.S. Federal water-related agencies that have smaller capability and less compre- hensive Great Lakes responsibilities. The Canadian government has recognized fully the urgency for ac- tion on the Great Lakes. It has started the construction of a federal labora- tory on Lake Ontario which, when completed in 1972, will house 250- 300 scientists and will be capable of surveillance of all water-quality, bi- ological, and fishery aspects of the Canadian portion of the Great Lakes. An even more substantial facility would be required to meet the full U.S. commitment on the Great Lakes, since the United States has 64 per- cent of the Great Lakes within its boundary and contributes some 80 to 90 percent of the industrial, urban, and agricultural contamination enter- ing the lakes. Problems of Eutrophication in the Great Lakes One of today's pressing problems is to formulate and execute a man- agement program for the nation's freshwater resources. These re- sources are of tremendous value; they are used for water supply (do- mestic, industrial, agricultural), rec- reation, navigation, hydroelectric power, waste disposal, and food sup- ply. Only a few of the nation's fresh waters are used for multiple purposes, and these few will be short-lived if present practices are followed. The underlying cause for this situation is the use of these waters for waste disposal, which results in chemical enrichment, or eutrophication, jeop- ardizing all other uses and producing a general deterioration of the human environment. Therefore, the over- riding water-resource problem is not water scarcity but water management directed toward control of pollutants at the source and means of ameliorat- ing the eutrophic effects of existing polluted waters. Among the numerous water bodies in the United States and Canada, the Great Lakes are the largest in area and volume and rank as the most important single water resource in respect to economic, recreational, and aesthetic values. They constitute about 40 percent of the total surface waters of North America, possess a drainage basin of 295,000 square miles in which live nearly 40 percent of this country's population. Accord- ing to reliable projections, these lakes lie in the pathway of the most rapid industrial and urban development in the United States and Canada. Despite their great value, there is an astonishing lack of fundamental knowledge about the Great Lakes. This stems from their great size, international and national political fragmentation of their drainage basin, need for an interdisciplinary approach to their complex problems, and need for meaningful, total system studies of this mesoscale aquatic system. Furthermore, there has been little sense of urgency in establishing management procedures for these wa- ters because of the misbelief that this vast quantity of water is capable of receiving almost unlimited quan- tities of pollutants without producing harmful effects. Inland communities use streams entering the Great Lakes to transport their waste without real- izing that the lakes become the even- tual receptors of this waste. Less is known about waste assimilation in lakes, especially large ones, than streams, but we do know that the residence time for pollutants is much greater in lakes. In streams residence time is on the order of days or weeks, while in the Great Lakes it is decades or centuries. It is evident that the Great Lakes environment is danger- ously susceptible to pollution because most avenues of waste disposal in the drainage basin terminate in these lakes. Physically, the Great Lakes drain- age basin is one system; but politi- cally it exhibits a pattern of frag- mentation. This physiographic unit is shared by eight states in the United States and two provinces in Canada. The heads of these political units can speak only for their respective units. There is no unified plan or approach for the management or utilization of their waters or the solution of common problems in the drainage basin. Within the United States, a dozen or more federal agen- cies are charged with Great Lakes missions, each carrying out its mis- sion commendably but none con- cerned with the lakes as a complete system. Superimposed on this pat- tern are the efforts by each Great Lakes state to deal with these waters within the framework of its policies. Only the International Joint Com- mission attempts to represent the international interests of the United States and Canada; it, too, has a com- mendable record of accomplishments but its objectives are limited. 267 PART VIII — AQUATIC ECOSYSTEMS The Great Lakes Basin Commis- sion, established in 1967, could pro- vide a mechanism for initiating re- gional planning and management. But although the mechanisms, the technical and scientific knowledge, and the manpower and economic need exist for unified efforts in pollution abatement, water-resources management, and regional planning of the Great Lakes drainage basin, these efforts are lacking. This fact is of deep concern, because decisions are being made and priorities estab- lished in the absence of a unified or regional plan or an understanding of the Great Lakes as a total system. Status of Great Lakes Eutrophication Although eutrophication of the Great Lakes is a pressing national problem, it has received little atten- tion until recently. Our understand- ing of the processes accounting for the lakes' aging and eutrophication (chemical enrichment) is based pri- marily on studies of small lakes, and much of this information is not di- rectly transferable to the Great Lakes because of scale difference. In general, aging processes begin at the time of lake origin and go on until the lake becomes extinct through filling, ecological succession, and eventual transformation into a ter- restrial habitat. Nature or direction of aging is controlled by such natural forces as erosion and deposition, hydrological and meteorological proc- esses, chemical enrichment, biological productivity, and ecological succes- sion. The time-span of lake existence may vary from a few decades to many centuries depending on the rates of these controlling forces or processes. These natural forces, operating in the absence of man, will produce a predictable direction and rate of change for a given ecosystem. But man, through his activities (cultural forces), modifies the natural trends and rates. Therefore, man's major role in lake aging is that of deter- mining the rates of change, especially through chemical enrichment, com- monly referred to as eutrophication. The activities of man that con- tribute significantly to the process of lake eutrophication are: 1. Discharge of domestic and in- dustrial wastes into waterways. 2. Land-use practices that result in runoff carrying silt loads, fertilizers, farm-animal wastes, and pesticides. 3. Discharge of waste heat from nuclear and fossil-fuel power plants and industrial processes. 4. Discharge of pollutants into the air, which eventually enter wa- terways by precipitation and fallout. Our limited knowledge of Great Lakes eutrophication has been de- rived from a large number of isolated studies over several decades. There has been no attempt at a unified, multidisciplinary study of one lake or of the total Great Lakes as a sys- tem. The general trends have been identified but the mechanisms and rates are known only qualitatively. The general status of Great Lakes eutrophication may be summarized as follows: Each of the five Great Lakes has undergone measurable en- vironmental changes in the past fifty years. The lakes are now character- ized by: 1. An increase in chemical con- tent of water and sediments (phosphorus, nitrogen, calcium, sulphate, potassium, and chlo- rine); 2. An increase in biological pro- ductivity; 3. A change in species composi- tion of biota; 4. A decrease in concentration of dissolved oxygen; 5. A decrease in transparency; 6. Highly polluted conditions in inshore areas, harbors, and bays. Lake Erie is the most advanced eutrophically because of its shallow- ness, its southernmost geographic lo- cation, and its large pollution input from urban, industrial, and agricul- tural sources. Lake Ontario ranks second as a result of its position furthest downstream in the intercon- nected system of five lakes and its large volume of deep water. It, too, has received heavy pollution inputs from cities, industries, and agricul- tural activities. Lake Michigan ranks third, with conditions in its southern one-third being similar to those of Lake Erie; the northern portion is of high quality, resembling conditions in Lakes Huron and Superior. The latter two lakes and the northern part of Lake Michigan comprise about 90 percent of the total volume of the Great Lakes; they represent the last large volume of good-quality water in the United States. The data base for the Great Lakes is poor. It lacks uniformity of qual- ity, and is sparse or lacking in certain areas. Much of the usable data have been collected at irregular times over a period of fifty years. There are serious data deficiencies in the follow- ing areas: 1. Lake circulation, both open- lake and inshore; 2. Characteristics of thermal bars that form inshore and isolate the nutrient-rich river effluents for periods of several weeks; 3. Quantity, concentration, and form of chemical inputs from domestic, industrial, and land drainage sources; 4. Atmospheric input; 268 LAKE EUTROPHICATION AND PRODUCTIVITY 5. Role of lake sediments in the cycling and storage of chemical substances; 6. The precise residence time of water in each lake basin; 7. Utilization and cycling of nu- trients by biota; 8. Population dynamics of various communities; 9. Energy budget; 10. Water budget. Without more complete information in these areas, the eutrophication of the Great Lakes cannot be effectively controlled. Importance of Scale in the Design of Great Lakes Studies The matter of transferability of information and experiences derived from studies of small to large lakes requires careful evaluation before a Great Lakes eutrophication program is established. Although the funda- mental processes of aquatic systems, whether large or small, are basically the same, the mechanisms controlling these processes and the rates may vary importantly with water-body size. In the size-series of water bodies from small lakes to oceans, the Great Lakes represent the mesoscale aquatic system. The lakes are subject to essentially the same physical, chemi- cal, biological, meteorological, and geological conditions as the oceans and they possess both lacustrine and oceanic characteristics. Nevertheless, a direct transfer of information from small lakes to these large lakes is difficult for a number of reasons. Some characteristics that make the Great Lakes uniquely different from small lakes are: 1. Visible effects of Coriolis force on water circulation; 2. Distribution of upwelling and sinking according to relation- ship of current streamlines and the shore; 3. Discrete water masses which maintain distinct limnological characteristics; 4. Modifying effect on weather; 5. Large water volume in propor- tion to area of water surface and lake bottom; 6. Existence of a wide range of industrial and urban complexes, land uses, shore development, and water uses in the 295,000 square miles of drainage basin; 7. Each of the five lakes differs in size, morphometry, and lim- nological characteristics, but they are interconnected, result- ing in a flow-through or down- stream effect; 8. Residence time for water in a lake basin may exceed 100 years. Scale, then, becomes an important factor in designing studies on the Great Lakes. Two ways to meet some of the inherent difficulties are: (a) extrapolation of experience from small to large lakes, including labo- ratory-type studies as well as studies from scale enclosures (plastic bags, cylinders, etc.) and the experience gained from intermediate-size lakes; and (b) development of appropriate mathematical models (black-box mod- els, hydrodynamic models, produc- tivity models, etc.). Transfer from physical models (small lakes) could be facilitated by developing some kinds of transfer coefficients, analogous to Reynold's numbers. Plans for Action It becomes apparent that water- resource problems of the Great Lakes are large, diverse, and urgent. There is general agreement among scien- tists, engineers, political scientists, and socio-economists that the most fruitful approach to the solution of these problems is a direct study of the lakes through use of systems- analysis techniques and a well-de- signed program of data collection and analysis. There is also basic agree- ment that an effective program to control Great Lakes eutrophication must place primary emphasis on con- trolling nutrients and pollutants at source of entry and secondary em- phasis on measures to ameliorate the effects of these substances after en- tering the lakes. Modeling Efforts — Several organi- zations and research teams are devel- oping a set of linked systems-modeling studies that will use simulation as a research tool in conjunction with the study of the Great Lakes. The long- range objective of this effort is to construct a region-wide comprehen- sive model. Initial efforts are directed toward a water-quality model on a regional scale, a water-quality sub- system model for one or more sub- regions within the Great Lakes basin, and a regional economic-growth model. These efforts are too new to have produced tangible results, but this kind of thinking dominates pres- ent Great Lakes investigations. The organizations offering leadership in this approach are: the Great Lakes Basin Commission, with emphasis on regional models; the Council on Eco- nomic Growth, Technology and Pub- lic Policy of the Committee on In- stitutional Cooperation (CIC), with emphasis on water-quantity and water-quality models; the University of Michigan Sea Grant Program, with emphasis on comprehensive modeling of a subregion (Grand Traverse Bay); and the University of Wisconsin Sea Grant Program, with emphasis on modeling of Green Bay. Data Collection and Systems Anal- ysis — Two field-data collection pro- grams and related systems-analysis efforts that are under serious con- sideration will serve as examples of current thinking on Great Lakes in- vestigations. The first is a materials- 269 PART VIII — AQUATIC ECOSYSTEMS balance study of one of the Great Lakes, preferably Lake Michigan be- cause it lies entirely within U.S. boundaries, simplifying operational logistics and interdisciplinary study, or Lake Ontario, which is the object of the International Field Study on the Great Lakes of the International Hydrological Program. This would involve a study measuring the input from industrial and urban sources, land drainage, and the atmosphere. The output would include measure- ments of loss through outlets, reten- tion by sediments, removal of biota, and loss to atmosphere. Other as- pects of the study would be directed toward the dispersal of input ma- terials in the lake by currents and general water circulation, and the interaction between input materials and the biota. The major problem to be solved by this study is the assimilation capacity of the lake wa- ter — that is, the amount of material it can receive without deterioration in quality. The object would be to prevent inputs above the assimilation capacity, as well as to determine the costs for maintaining a given water quality. This would require estab- lishment of water-use priorities, a political decision yet to be made. Also, information on the kinds, quan- tities, and concentration of materials entering the lake would make it pos- sible to evaluate the relative impor- tance of a pollution source and to identify the sites where pollution- control measures would be most ef- fective. Moreover, it would produce high-quality information essential for predictive capabilities (modeling) con- cerning the nature and rates of eu- trophication, and it would serve as a model for studies of the other Great Lakes. A large part of the required data for this materials balance is presently being collected by several federal and state agencies and regional univer- sities conducting investigations on Lake Michigan and its drainage basin. Success of this study would require cooperation among these organiza- tions. The organizational structures, personnel, and facilities are in exist- ence; only a coordinated effort is needed. Such a study would not lessen the present need to deal with urgent local problems by federal and state agencies, but it would produce new and exciting possibilities for attacking pressing Great Lakes prob- lems on the basis of a total system and long-term planning. In the second example, the pro- posed study would focus on a major river system, such as the Grand River in the Lake Michigan basin, aimed at determining the impact of its dis- charge on the inshore lake waters receiving it, and alternative methods of reducing this impact. A materials balance of the river and the source of materials would be determined for the entire river. The accompanying systems analysis, among other things, would determine the benefit/cost im- plication of maintaining an acceptable water-quality standard and would pinpoint alternatives for solving the local water-resource problems. The impact of river discharge on the in- shore area would involve studies of currents, thermal-bar phenomena, and biochemical interactions. The significance of such a study is evident when it is realized that approximately 90 percent of the pollutants entering the lakes do so through river systems. This would serve as a model for at- tacking the problems of other major rivers entering the lakes. Expected Results — These sug- gested attacks on Great Lakes eu- trophication would identify rather specifically: the need for new instru- mentation such as automatic monitor- ing devices; the application of remote sensing methods to water-resource investigations; the prevailing socio- economic and political problems; and the need for an interdisciplinary ef- fort involving the cooperation of personnel from universities, industry, and government. It would also make possible reasonable estimates of costs involved in establishing a manage- ment program for the entire Great Lakes basin. The high rate of Great Lakes eutrophication argues for im- mediate action on the general prob- lems presented in this discussion. Pollution and Recovery in Lake Washington The city of Seattle lies between Puget Sound and the west side of Lake Washington. Early in this cen- tury, the lake was used for disposal of raw sewage, and unsatisfactory conditions developed. In the early 1930's, most of the sewage was di- verted to Puget Sound, and for a few years the pollution of the lake was considerably reduced. But Seattle was expanding and smaller towns around the lake were growing. In 1941, a two-stage biological sewage-treatment plant was established on the lake, and by 1954 ten such plants had been built. Another one was built on one of the inlets to the lake in 1959. In addition, some of the smaller streams were heavily contaminated with drainage from septic tanks. Studies of the lake in 1933, 1950, and 1952 showed increases in the content of algae and nutrients and decreases in the amount of oxygen in the deep water during summer. In 1955, a conspicuous growth of the alga Oscillatoria rubescens de- veloped. This event attracted atten- tion because this species had occurred 270 LAKE EUTROPHICATION AND PRODUCTIVITY early in the process of deterioration of a number of European lakes. Thus, it seemed to be a distinct harbinger of pollutional deterioration. Eutrophication — The problem is that sewage treated ("purified") by normal processes is relatively rich in nutrients, especially phosphate. As a result, when the effluent is put into a lake, it acts as a plant fertilizer and stimulates the growth of algae. While some increase in biological production may be favorable, overproduction of algae results in water of low trans- parency; large quantities of decaying algae also produce bad odor prob- lems. In such lakes, dissolved oxygen may be exhausted from the deep wa- ter by decomposition, and this elimi- nates many desirable species of fish (whitefish, trout, salmon). These con- ditions interfere with most uses of a lake — recreational, water supply, and fisheries. As long as the sewage is well treated, human health problems are not dominant, but some individ- uals are sensitive to algae and develop skin rashes or nausea when they are in contact with the lake. This effect of pollution, often called eutrophication, is common around the world. It is well documented by many studies. Lake Washington was thus exhibiting perfectly normal be- havior when its increase in the abun- dance of algae began. Public Action — Public concern over the sewerage situation had been growing in the entire Seattle metro- politan area. In 1955, the Mayor of Seattle appointed a Metropolitan Problems Advisory Committee to study sewerage conditions, among other things. The obvious beginning of deterioration of Lake Washington and the rather clear-cut predictions that could be made about its future condition gave focus to public con- cern. At the same time, it was recog- nized that unsatisfactory conditions also existed in Puget Sound and that a broadly based, coordinated program was necessary. As a result of the Committee's ac- tion, a campaign was organized by public-minded citizens' groups to de- velop a governmental organization to handle the problem (Municipality of Metropolitan Seattle, or "Metro"). An active informational campaign was carried out, mostly using infor- mation about the actual deterioration of Lake Washington and predictions about its future. After a certain amount of difficulty, Metro was passed on the second vote in 1958. A project of sewage diver- sion from the lake was started in 1963 and completed in 196S. The total cost of Metro to date is about $145 million, of which about $85 million is attributable to the Lake Washington part of the project. Results of Diversion of Sewage — With the first diversion of about a third of the sewage, deterioration of Lake Washington slowed, and further diversions were promptly followed by more improvement as measured by increased transparency of the water and decreased amounts of phos- phorus and algae. During late sum- mer of 1969, the deep-water oxygen conditions were more favorable than in 1933, phosphate was nearly down to the concentrations seen in 1950, and summer transparency was two- and-a-half times as great as in 1963. (See Figure VIII-16) It is important to realize that action was taken before the lake had de- teriorated very far, relative to the well-known problem lakes in Europe and the Midwest of this country. The condition of the lake changed conspicuously enough that there was no doubt about its reality, but action was taken early in the process. Generalizations from the Lake Washington Experience It is clear that Lake Washington responded promptly and sensitively to both increases and decreases in nutrient input. Lake Washington should not be regarded as unusual; many lakes are similar enough in their chemical characteristics that Figure VIII-16 — TRANSPARENCY MEASUREMENTS IN LAKE WASHINGTON Meters SECCHI 1- ^---■- •—- '"" ' 1963 "*"•.., 2- .1970 3 — 4- /■if A --"" \ \ \ \ / 1 \ \ \ \ 1971 1950 5- MAR 1 APR ' MAY ' JUNE JULY 1 AUG SEPT 1 OCT The graph shows observations of transparency made in Lake Washington from 1950 to 1971. The measurements are made with a Secchi disc, a 20-centimeter white disc that is lowered into the water until it disappears from view. 271 PART VIII — AQUATIC ECOSYSTEMS they would respond just as sensi- tively. These considerations are rel- evant to making predictions and to the development of plans for han- dling the pollution of the Great Lakes and others that are receiving effluent or are going to. If one is going to make a complete statement about the processes that control the productivity and abun- dance of organisms in lakes, he has to refer to the whole set of environ- mental variables: nutrients including (in addition to nitrogen and phos- phorus) carbon, such micronutrients as iron, copper, cobalt, and others. He has to discuss light penetration into lakes, the kinetics of photosyn- thesis, and a great many other things. But to take practical steps to improve the condition of a particular lake that has been polluted is another matter. It is not necessary to recapitulate the entire history of limnological investi- gation in that lake. We know a great deal already, and can make use of the general knowledge we have de- veloped from pure limnological re- search. A point of particular interest has to do with the relative importance of phosphorus (P) and nitrogen (Nj, a matter about which there has been some uncertainty. For practical con- trol, the proposition very often would be to ask what the effect would be of removing most of the phosphorus from the effluent. That is, to simplify a little, what would be the effect of heavily enriching with nitrogen? The answer to this has to lie in the condi- tion of the receiving water. If the natural waters, for geological reasons, are relatively rich in N, so that P is the primary limiting factor, phos- phorus enrichment is likely to in- crease production. The obvious thing to do is to find out which element is limiting in each particular case. A variety of techniques exist, ranging from bio- assay with lake-water samples to which nutrients are added through analysis of lake water and plankton for N and P. Some studies have shown that added P alone was enough or almost enough to account for the observed effect of sewage. Another rather new approach to this problem of diagnosis shows that in Lake Washington, before pollu- tion, nitrate was in excess in the sense that when phosphate approached zero during the spring growth of phyto- plankton, there was a distinct excess of nitrogen. After pollution with phosphorus-rich sewage, P was in excess in 1962. In 1962, then, Lake Washington might well have re- sponded to an increase in nitrogen which would have permitted the phosphorus to be used up. This point is easy to get mixed up. One must keep clear whether one is talking about the effect of adding an element or removing it. One does the first when trying to explain why a given lake has gone into nuisance conditions; one does the latter when thinking about how to improve the situation by removing something. In June of 1962, adding phosphorus to Lake Washington would not have increased algae because there was an excess. Removing phosphorus would have decreased algae. In the long run P is the more im- portant element in much of the world. But there are places where phos- phorus is relatively rich in the nat- ural water supplies. Goldman has proposed, for instance, that Lake Tahoe would be susceptive to ni- trogen enrichment. Also, there are some organisms that seem able to get along with much less phosphorus than others. If all this is correct, then for each case we have to identify a key ele- ment, limitation of which would im- prove the lake. One could theoreti- cally limit production by eliminating any essential element, but in fact there are very few elements that one can control. The single element that is most easily removed from effluents is phosphorus. So the question boils down to asking whether limiting phosphorus, either by removal from sewage or by limiting detergents, will be enough to make an adequate dif- ference. This means, too, that one must find out whether there is enough P from agricultural drainage into a given lake to make a difference. In Lake Washington, phosphorus has decreased much more than nitro- gen or carbon dioxide. (Sewage is relatively much richer in phosphorus than is the natural water supply to the lake.) The abundance of algae has decreased in very close relation to phosphorus, not in relation to nitrogen. (See Figure VIII— 17) This suggests that, in similar lakes, any limitation on the amount of concen- trated sources of phosphorus reaching the lake will be beneficial. That is, improvement should result in propor- tion to the removal of concentrated sources of phosphorus. Large changes could be made by reducing the phos- phorus content of detergents. In some places it may be worthwhile to install treatment processes to remove phosphorus from effluent. This discussion is focused on the eutrophication problem. Inflow of toxic wastes (lead, mercury, cyanide, herbicides, DDT, etc.) was not an important part of the Lake Washing- ton problem, but it evidently is a part of the Lake Erie problem. In every case of lake deterioration, one should find out if toxic wastes are important. Nevertheless, Lake Erie would prob- ably be measurably improved by lim- itation of sewage phosphorus. Char- acterizing Lake Erie as "dead" seems quite incorrect. Unsolved Problems Plenty of interesting problems re- main in studying the natural mech- anism of control of productivity and abundance of organisms in lakes. In particular, what is the relation between the rate of input of nutrients and the productivity of lakes? It is common to express the annual input 272 LAKE EUTROPHICATION AND PRODUCTIVITY Figure VIII-17 — MEASUREMENTS OF ALGAE, PHOSPHORUS, AND NITROGEN IN LAKE WASHINGTON 150 125 100 CD > Z 75 50 — 25 CHLOROPHYLL y &."" ** \ • • i * ~~"J? — • •**,, \ ♦ % ♦ A V '*•• — / * NITROGEN \ \ i i PHOSPHATE "*^\ 1 1 1 1 1 1 1962 1963 1964 1965 1966 YEARS 1967 1968 1969 The graph shows observations from 1962 to 1969 of the abundance of algae, and the concentration of phosphates and nitrates. Yearly values are percentages of the 1963 values of the concentrations. on an areal basis as kilograms per hectare or pounds per acre. But this is an imperfect and even misleading calculation. Obviously, the effect of a given input will vary with the depth and volume of the lake. That is, a given input will affect a shallow lake more than a deep one. Also, this calculation takes no ac- count of the fact that some of the influents are much more concentrated than others. It seems evident that a very concentrated source relative to lake water will mix in and raise the nutrient content of the lake, while a source with the same con- centration will merely displace an equal volume and not make a net increase. This is why sewage effluent is so important relative to any normal ground drainage: it can be 1,000 times as concentrated in phosphorus as the natural water. One could double the nutrient input of a lake either by doubling the rate of inflow at the same concentration or by doubling the concentration in the same inflow. The effects are likely to be quite different. Thus, we have to learn how to deal with the water budget as well as the nutrient budget, and to cal- culate the relative effect of influents of different concentration. From the general viewpoint of basic "pure science" limnology, this would im- prove our understanding of the com- parative limnology of productivity — why lake districts tend to have a certain uniformity and yet why in- dividual lakes in one region differ in productivity. Obviously, improvements in our understanding of these matters would be of tremendous practical impor- tance. In few situations can there be a clean, clear-cut, total diversion of sewage as with Lake Washington. Often one will want to know what would be the effect of making some percentage reduction in the phos- phorus content of sewage, or of di- verting some fraction of the effluent. There is also the question of the effectiveness of agricultural drainage, which has probably been exaggerated. Nevertheless, we could find out whether it would be worthwhile try- ing to modify agricultural practices in a watershed. Conversely, one might want to make a very precise adjustment of enrichment to maintain fish produc- tion at as high a level as possible without damaging the desired species or creating algal nuisances. The problem, then, is to improve the predictability of limnological con- ditions, especially the productivity and abundance of organisms. Demonstrably, Lake Washington has permitted a step forward in this direction, but we have a long way to go. Progress is more likely to be made by limnologists working with very broad questions than by any- body else working with very specific and limited questions on a purely practical basis. Progress will be faster and better if some more experi- ments can be carried out with real lakes. For example, Lake Erie might be regarded as a prime object for limnological experimentation. 273 PART IX TERRESTRIAL ECOSYSTEMS 1. COMPONENT RELATIONSHIPS Environmental Design All living organisms modify their environment and leave their imprint on it. This imprint leads to environ- mental change. The uniqueness of the human imprint is in its scale and tempo. Both by accident and by con- scious intent, man has been and con- tinues to be engaged in environmental modifications that are extensive, in- tensive, and rapid. His interventions in and manipulations of the processes of the planetary life-support system (ecosystem) have produced a set of complex problems — the problems of environmental design. The entire planet has become man's niche. He is reshaping the world. The natural ecosystem is being trans- formed into a human ecosystem. Just as the development of a natural eco- system can be characterized by a con- tinuum of serai stages ranging from primitive to climax (see Figure IX-1) so can the transformation of natural ecosystem to human ecosystem. A continuum of anthroposeres com- prises the stages of succession. The primitive stage includes a collection of shelters, a discrete cultural tradi- tion, and hunting and gathering to support subsistence. The most recent stage consists of an interlocking web of subsystems each of which includes the city, its satellite towns and vil- lages, a diversity of cultural tradi- tions, a complex of communication links to areas of agricultural produc- tion, pools of wild plant and animal genes, natural resources, depots for wastes, and recreational sites. In- creasingly, man is drawing on the resources of landscape and allocating them to the fulfillment of his own needs and requirements. Perhaps the climax stage will be the total trans- formation of the natural ecosystem to a human ecosystem. As the human population multiplies, this process of transformation accelerates. Man in- tervenes more and more in ecological Figure IX-1 — SERAL STAGES OF A DECIDUOUS FOREST MANAGED FOREST upto20t/ha BUILDINGS UNPRODUCTIVE OF CRYPTOGAMS FIELDS 5-25 t/ha This figure is a schematic diagram of the successional sequence in a deciduous forest. The rectangular areas indicate where man has arrested the successional sequence to create other systems. The numbers indicate annual dry-matter produc- tion in metric tons per hectare (1t/ha = 100g/m-). Cryptogams are plants — ferns, mosses, algae, and the like — which reproduce by spores and do not produce flowers or seeds. 277 PART IX — TERRESTRIAL ECOSYSTEMS processes that he does not fully comprehend. There are two reasons for the prob- lems of environmental design. First, man cannot, with any certainty, now foretell the consequences of the trans- formations in which he is engaged. Second, he cannot yet design alter- nate processes for his own ecosystem that will assure his survival. Some Specifics In his design of the environment, man seems to have locked himself into a course that will bring him to the climax visualized before he has developed the knowledge and skills for managing such a human ecosys- tem. This is the essence of the prob- lem. We shall examine briefly a few aspects in order to gain a per- spective on the decisions about en- vironmental design that man must make in the decades ahead. Urban Growth — From the view- point of environmental design, the city may be conceptualized as an empirical allocation of the landscape to accommodate high population den- sities in functionally effective con- figurations of structures, spaces, in- stitutions, and processes. Although the city gives the appearance of in- dependent existence, it is inexorably bound to its surround, for the city is a specialized consumer of resources. It is entirely dependent on a continu- ing inflow of biological and physical- chemical resources for its very ex- istence. These resources include foodstuffs, fuels, and a variety of raw materials. Its productivity can be measured in terms of diverse fabrications. The city has become the scene of some intriguing shifts of population. There is at once an outward migration of people from the central city to the suburbs and an inward migration of people from the country to the city. To accommodate these flows, urban sprawl has developed; the central city, which began to deteriorate, is being rebuilt to house greater popu- lation densities; and vast transporta- tion links have been constructed to carry workers between residence and place of work and to relate the city to its surround. The spread of the city has consumed large areas of pro- ductive agricultural land. The shift of population into high-density areas has sharpened the dependence of the city on the remaining agricultural lands and on the efficiency and effec- tiveness of the communication links with that managed landscape. Monoculture and the Shrinking Gene Pool — For relatively fewer and fewer persons to support the growing dependent populations residing in high-density areas, the productivity of agricultural lands must be con- tinually intensified. High produc- tivity demands that an increasing amount of the landscape be trans- formed from low-producing climax associations of a diversity of plants and animals to high-producing mono- cultures of domesticated plants and animals bred to provide for human needs and requirements and for re- sistance to pathogens and adverse weather conditions, particularly cold and drought. To assure that these managed lands are maintained as monocultures, they are protected from invaders by a variety of biocides toxic to the invaders but not toxic to the domesticated organisms or the con- sumers of the produce. Because the nutrients extracted from the soil by the domesticates are not recycled but diverted to the human consumers, the nutrients must be restored as chemi- cal fertilizers. To maintain the vigor and the resistance of the domesti- cates, they must be continually inbred with material from appropriate wild genes. As the demands upon the land- scape intensify, its transformation to managed agricultural systems spreads and the space that can be allocated to pools of wild plant and animal genes shrinks. As the stocks of wild genes diminish, the opportunity for invigo- rating the domesticates and for pro- viding new domesticates is reduced. Because man's food base is already rather narrow, an important decision in environmental design will be how to provide adequate space for reser- voirs of wild plant and animal genes. Conservation and Recycling of Re- sources — Reservoirs of wild genes represent only one decision in envi- ronmental design to conserve natural resources essential for the human eco- system. Because of their vital role in subsistence, steps must be taken to preserve the quality of lakes, rivers, estuaries, and zones of oceanic up- welling so that their biological pro- ductivity is maintained. Man also extracts other natural resources from the landscape. These resources pro- vide fuel to support his activities and materials for his fabrications. Be- cause the supply of these resources is finite, environmental designers must plan for their conservation, allo- cation among competing needs, and processes whereby essential materials may be recycled. Managing feedback in the emerg- ing human ecosystem is one of the most complex problems in environ- mental design. In the natural eco- system, organic detritus is fed back into the environment and recycled into new organic forms. Relatively little detritus accumulates in the en- vironment. Man adapted his methods of managing wastes to the processes of the natural ecosystem, but the scale and tempo of waste production have exceeded the capacity of natural feed- backs and the toxic nature of the human detritus has disrupted the orderly functioning of the organisms in the ecosystem. Man must now de- vise innovative processes to manage the rapidly accumulating detritus of the human ecosystem. Because the resources of the land- scape are limited, the decisions of environmental design for the alloca- tion of these resources among com- peting demands must include the 278 COMPONENT RELATIONSHIPS principle of multiple use. The most pressing demand that might best be handled by this principle stems from the time man has for leisure. A re- sponse to population growth is a shorter work period for each indi- vidual. As a consequence, there will be an increase not only in numbers of persons but also in the time avail- able to each person for constructively filling leisure time. Among the ways of using leisure time is to engage in any one of a number of outdoor rec- reational activities. The demand for this type of leisure outlet is already mounting and the pressure will not diminish. Therefore, in designing the environment it will be necessary to allocate to recreation a variety of re- sources that can fill these specific needs as well as the more general needs of the human ecosystem. Quantitative Analysis — The prob- lems of environmental design are problems of ecosystems analysis. Largely through the initiative of sci- entists associated with the Interna- tional Biological Program, a beginning has been made on the comprehensive and quantitative analysis of ecosys- tems. (See, for example, Figure IX-2) In order to be able to guide the transformation of natural ecosystems to human ecosystems, detailed quan- titative knowledge must be available of the processes and regulations of the planetary life-support system. Techniques must be in hand for com- prehensive surveillance and monitor- ing of appropriate physical, chemical, biological, and social indicators. Sim- ulation models of ecosystems must be available to study and predict the outcomes of alternative strategies in environmental design. In large part, these expectations can be fulfilled through analysis of ecosystems. Criteria for Environmental Quality — The quality of the environment is another facet of the problems of en- vironmental design. As the transfor- mation from natural to human eco- system proceeds, it will be necessary to preserve environmental qualities essential to the continuing productiv- ity and vitality of the biosphere and those adjunctive qualities that insure the habitability of the environment. At the same time it will be necessary to limit the accumulation of wastes in air, water, and soil and regulate the use of agricultural chemicals and food additives so as not to jeopardize the fitness of the ecosystem. The task of formulating criteria to serve as Requirements for Scientific Activity Figure IX-2 — A SYSTEMS MODEL FOR A GRASSLAND ECOSYSTEM Science is on the threshold of real- istically tackling these problems of environmental design. At the very least, the problems can be stated in broad perspective. That in itself is a start in the direction of formulating approaches to their solution. A-disciplinarity — These problems are a-disciplinary. That is, they re- late at once to no particular discipline yet involve many, perhaps all disci- plines. The major problems of the sciences concerned with environment make meaningless the traditional boundaries that have separated man's compartmentalization of knowledge and methodology. That science is on the threshold of tackling a-discipli- nary problems is evidenced by the increasing use of such phrases as in- terdisciplinary, multidisciplinary, pan- disciplinary, and problem-oriented configurations of diverse specialists. Apparently, some scientists are ready to leave their feudal baronies and join in innovative configurations specifi- cally focused on solving well-defined problems, however complex they may be. O extrinsic variable Q intrinsic variable — * mass /energy transfer ---» controlling influence j [ \ trophic/functional group of* variables HERB1V0RY ATMOSPHERE 6 RUN-OFF This diagram represents a significant step forward in the conceptual approach to the study of an ecosystem and has proved invaluable in the design of research, team organization, and analysis of data. Nonetheless, the level of sophistication shown here is well below that needed for application in practical problems. The complexities arising from the several hundred species and several thousand relation- ships are still overly simplified, as are the interactions of the system with human intervention. This figure is typical of the general level of modeling in all subfields of environmental science, and demonstrates the youth of the field. 279 PART IX — TERRESTRIAL ECOSYSTEMS guidelines for designing environ- mental quality has only just begun. In part, information on which to base these criteria will emerge from the analysis of ecosystems. However, more attention must be devoted to the biology of man, for he is the least systematically studied organism from the viewpoints of function and be- havior. Leisure Science — In terms of ful- filling man's needs and requirements, systematic studies must be under- taken of what has been called leisure science. The constructive and re- warding use of leisure time will be one of the central problems of en- vironmental design and scientists have just begun to look at this prob- lem area. The gamut of the problems of leisure includes the physiology, psychology, and sociology of leisure, recreational facilities and resources, and tourism. Implementation We have examined the problems of environmental design in broad per- spective. We have noted that there is a readiness on the part of scientists to become involved in the compre- hensive and complex tasks that must be undertaken for the solution of these problems. In particular, we have pointed to an emergence of such studies as ecosystems analysis, cri- teria of environmental quality, human biology, and leisure science. What might be done to implement the study of the problems of environmental design? Because the problems of environ- mental design are adisciplinary, it will be necessary to develop institu- tions wherein problem-oriented con- figurations of scholars can be brought together to work effectively and effi- ciently in teaching and research. The administration of these institutions is most important, for being able to manage adisciplinary work is just as relevant as knowing how to tackle problem-oriented studies. It can be argued, for example, that present-day crises are just as much managerial crises as they are environmental ones. These institutional formulations are being explored in the federal estab- lishment, in state governments, and at colleges and universities. Progress has been slow because traditional values and alignments are difficult to overcome. Innovation creates inse- curity among established feudal ba- ronies. Allocation of limited finan- cial resources between the old and the new strains both institutional for- mulations. Because there is a growing commitment to developing innova- tive problem-oriented institutions, it would seem most important that this commitment be realistically and re- sponsibly encouraged. Maintenance of the Biosphere, with Special Reference to Arid Lands For centuries, man has been im- posing unusual stresses on the eco- systems with which he comes into contact. Probably no other organism has so rapidly, and on such a world- wide scale, forced far-reaching changes on ecosystems previously in equilibrium. By removing particular species of plants, clearing land for crops, changing the balance between herbivores and their predators, alter- ing the patterns of water movement, or spreading poisons through the landscape, man has imposed his will on nature. But man's will has been short- sighted. Accustomed in most of the workaday world to see the results of his efforts in hours, days, or, at the most, in the interval from seedtime to harvest, he has not realized that ecosystems operate on a time-scale which, though short by evolutionary standards, is long by his own. It may take a generation or a century before the more far-reaching effects of his modification of ecosystems become fully apparent. In order to attain wisdom in his relations with natural ecosystems he must, consequently, develop long-sightedness — he must find means of predicting what the effect of his actions will be, not to- morrow, but next century. The arid lands constitute a part of the biosphere that is more vulnerable than most. The desert areas of the Near and Middle East stand today as a lasting reminder of man's ability to modify — albeit unintentionally — this part of his environment. It is only by an attempt to regard eco- systems as wholes, and to develop an understanding of their dynamics, that such dangers can be averted and wise use of these delicately poised areas can be assured. To do so requires a reversal of what has for decades been the main current of scientific endeavor. Analytical vs. Systems Approaches When man looks at and considers his surroundings, he feels impelled to divide them into discrete units which he can classify and name. His mode of thought is based on verbalized categories and is not adapted to con- tinuous variation and interrelation. Furthermore, just as giving something a name may tend to divert attention from the thing to the name one has given it, so categorization of one's surroundings diverts attention from the real whole to the categories into which it has been divided. Science has long been concerned mainly with these discrete entities 280 COMPONENT RELATIONSHIPS into which the environment has been divided — discrete in thought, though not in reality- And many of these entities have been so sundered as to be the subject of separate disciplines requiring quite different training. The meteorologist and the entomolo- gist, the bryologist and the hydrolo- gist are unlikely to come into contact, and unlikely to understand one an- other if they do. Yet weather and insects, mosses and streams are parts of a common over-all pattern within the landscape, and understanding of each considered in isolation is bound to be imperfect. Even within a discipline it has been usual to narrow the focus, so that one is looking at a particular organism, a particular function, a particular organ or tissue — perhaps the role of sto- mata in controlling transpiration, the function of kidney tubules, the en- zyme systems of glycolysis, or the mechanism of adsorption of ions on the surface of clay particles. This analytical approach in science — constantly subdividing one's cate- gories, and getting to know more and more about less and less — has had great success. But there is no doubt that its practitioners have found it difficult to see the woods for the trees. Over the past twenty years a reali- zation has been growing that this fragmented attitude is inadequate to the subject matter of scientific study. Science is recognizing the need to try to fit the pieces together again and return to the complex whole that is reality. One form of this newly prominent synthetic effort is what has become known as systems analy- sis, involving the application of math- ematical and computer techniques to the problem. Systems Ecology — Systems analy- sis applied to ecology ("systems ecol- ogy") views the ecosystem as a whole and examines processes within it as they depend on all the other com- ponents of the ecosystem — meteoro- logical factors, soil, plants, animals, and microorganisms. In the analytic approach, the photosynthetic rate of a leaf was viewed in isolation as de- pendent on the radiation impinging on it, and the temperature and hu- midity of the air around it. Perhaps the analytic approach delved even deeper, and the oxygen exchange of a chloroplast was viewed as a func- tion of the radiation of different wavelengths absorbed by the pig- ments and the ionic balance of the protoplasm in which it was embedded. In systems ecology, in contrast, the focus is broader, and attention is di- rected to the gas exchange of the vegetation as a whole, or perhaps to each of the populations of different species of which it is composed; changes in rate of this process are considered, not in a simpler system actually or conceptually isolated, but in their whole real-world context — affected by the general meteorology of the area, by the soil which deter- mines the supply of water and nutri- ents to the roots, by the animals exerting selective defoliation, polli- nating, or transporting propagules. In arriving at this overview, sys- tems ecology may indeed make use of the results of analytic studies covering parts of the system. But the process of synthesis will demonstrate processes and effects in the ecosystem that would never have been recog- nized if the partial processes had been considered only in isolation. Systems ecology does not avoid the need for simplification — ecosystems are indeed so complex that to think about them in their full complexity would be beyond human powers, even with any conceivable concentra- tion of mechanical aids. But whereas the scientific approach of earlier dec- ades has been by subdivision and isolation — what one might call a "vertical" simplification — systems analysis requires a "horizontal" sim- plification, in which all major com- ponents are considered but each is whittled down to the bare essentials. Models and Submodels Generally, the synthesis of partial processes into a representation of the ecosystem as a whole is conceived in terms of a model. The practical proc- ess of building and testing models is closely linked with the use of com- puters, both digital and analogue (or hybrid) — in fact, it is doubtful whether this activity would even have approached its present development without the availability of computers. Once a model is built, a computer program representing it may be writ- ten, and repeated operation of the computer program then simulates the behavior of the ecosystem, as simpli- fied in the model, under different sets of conditions. Empirical tests of this sort can then play a valuable part in improving the model, even where the analytical work involved in a direct approach would daunt a mathemati- cian. The process of model devel- opment using computer simulation consequently has a large "boot-strap- ping" component. Development of an ecosystem model is sometimes based on obser- vations of the ecosystem as a whole — changes in quantities within it, or rate of processes such as the move- ment of material from one part of it to another. It may take the form of a set of differential equations with coefficients to be estimated, perhaps subject to constraints. Alternatively, the model may be divided into a number of submodels, each of which can be studied separately and its best mathematical representation (again in terms of differential or difference equations) determined. Figure IX-3 is an example of one such submodel. The submodels are then combined, and the performance of the model as a whole studied. These two approaches may in fact arrive at a model of the same struc- ture, but the estimates of constants will differ. If they are of the same structure, the fit to the set of data used will be better with the first ap- 281 PART IX — TERRESTRIAL ECOSYSTEMS Figure IX-3 — MOSQUITO SUBMODEL WATER WATER VOLUME 5 EVAP TEMP y HIBER- NATING FEMALES ^ * EGGS M LARVAE -K Y, U PUPAE -DC ^f ADULTS V, MORTALITY The figure is a submodel, or subsystem, of the larger desert ecosystem model. This particular submodel is designed to elucidate how water level and temperature affect the production of mosquitos in desert playas. Note that water volume is important initially to the female and the laying of the eggs whereas temperature is important throughout all stages in the mosquito's life; temperature is also important to the effectiveness of the water volume. proach; but these data will them- selves provide no validation of the model. In general, however, the de- velopment of separate submodels as a first step is likely to lead to a more sophisticated total model, with greater variety in its content, than is likely to be attained by using trial and error to modify a complete model without subdivisions. On the other hand, the possibility that important elements of interaction between submodels de- veloped separately may affect their behavior when brought together is an ever present danger with this ap- proach, and must be examined by validation comparisons of model be- havior with that of the ecosystem as a whole. Data Base — Both approaches to ecosystem modeling, and modifica- tions of them, have been explored in recent years, and various simple mod- els have been developed for aquatic and terrestrial systems. Only excep- tionally, however, have the data been sufficient even for the construction of a model, let alone for testing it. The reason is that the data have usually been collected earlier, perhaps for a different purpose, and without reference to the particular type of model that was being built. Even where data were collected with model- ing requirements in mind, the de- velopment of the model has often indicated the need for data additional to those already collected. Standard Models — The problem of modeling does not need to be tackled afresh and independently for each new ecosystem that comes under scrutiny. There is a great deal in common in the general structure of relationships within different terres- trial ecosystems, even as diverse as tundra and tropical forest, though none of the species are the same and the balance of the various life forms and processes is quite different. Even between aquatic and terrestrial sys- tems, there are numerous analogies. Consequently, it may be expected that experience in modeling one type of ecosystem will greatly simplify the problems when a new type of eco- system is considered, though all pa- rameters may have to be estimated afresh. Moreover, the value of model de- velopment is not limited by national frontiers. Where the same landforms and biota occur on both sides of a frontier the same models can be ex- pected to represent the ecosystems there, so that a model for the Sonoran desert in Arizona should also apply to the Sonoran desert in Mexico. Even where different biota are in- volved in different countries, the gen- eral ecosystem structure as repre- sented in the model will often be the same, and only the constants and data used may need to be changed in order that the same models should be applicable. Terrestrial Systems — In general, the more successful models have been concerned with aquatic ecosystems; they are simpler, with fewer com- ponents, and limnologists are more accustomed to recording a wide range of data than are terrestrial ecolo- gists. Few terrestrial models cover more than a limited selection of eco- system components. In the arid lands, particularly, it is not possible to point to any complete ecosystem model based on well-authenticated data. The paucity of models for com- plete terrestrial systems does not indicate a similar lack for subsystems. Certain parts of terrestrial systems have been the subject of considerable modeling activity. Some aspects of meteorology, for instance, are well served in this way, as is hydrology. There are models for soil nitrogen cycling, for photosynthesis and plant 282 COM.XINrNT RELATIONSHIPS growth, and for predation. Many of these submodels, however, have only been claimed to apply in greatly sim- plified systems, and it remains to be seen whether they are also relevant in more complex natural systems. Uses for Models As for the use to which models can be put, it is easier to indicate pos- sibilities than to point to examples of their actual use. We will leave aside uses at the intermediate stages of the model-building process, where an imperfect model can itself, by the development of internal inconsisten- cies over a long computer run, or by sensitivity analysis of various param- eter estimates, point to ways in which it can be improved. The process of model building is indeed highly in- structive, and aids greatly in the de- velopment of insights into the func- tioning of ecosystems. Once a model has been built and validated, though, it can be used for purposes extrinsic to its construction. Experimentation — The model can, for instance, be used for experimenta- tion on scales that are impracticable in real life, and many sources of error inescapable in the field can be eliminated. Questions can be asked and answered, for instance, on the effects of competition between species under different meteorological conditions. Such questions could be included in a field experiment only by extending it over different years or different locations, where extraneous and irrelevant sources of variation would be introduced. Environmental Management — When the treatments postulated for the model are such as would be pos- sible in practice, this use of the model leads directly to its potential value as a management tool. The effects of any proposed manipulation may be explored far more quickly and cheaply than would be possible in the field, and, either by trial and error or by a formal optimization procedure, a choice can be made among a number of possible management strategies, once goals have been clearly defined. In the arid lands, for example, the management goals that might be set for particular areas could include prevention of soil erosion by wind and water; increased runoff of groundwater recharge; increased (or maintained) grazing capacity for domestic livestock; increased num- bers of wildlife (either for hunters or as an amenity); and even increased landscape values, insofar as they can be defined (good strands of flowering ephemerals following rain, or good growth of the more spectacular plants — Joshua tree, saguaro, palo verde — might fill this bill). The practicable management treat- ments would certainly include dif- ferent grazing practices (livestock type, density, and season, together with methods of stock control); shrub removal and/or seeding; wild- life control — by hunting permits, for example; introduction of exotics (plants and animals); and perhaps weather modification. The existence of a reliable model of the system, and a convenient computer imple- mentation, would enable the effects of any of these proposed treatments to be evaluated in terms of the selected goals (appropriately weighted if multiple); the whole could then be subjected to benefit/cost analysis. The arid lands of the United States are under heavy developmental pres- sure, which is likely to increase rather than decrease. The multiple-use con- cept often applied to them usually means multiple stresses. Yet manage- ment, except in limited fields, is per- force largely intuitive at present. Development of the management tools outlined in the previous para- graphs, accordingly, takes on the look of urgency where our arid lands are concerned. Needed Scientific Activity We should now examine what are likely to be the roadblocks restrict- ing progress in this direction — where and what sort of scientific effort will need to be expended to make these possibilities into realities. Monitoring — The range of eco- systems currently being monitored adequately to provide satisfactory tests of alternative models is far too small. It is of the greatest importance that the ecosystem models produced should be of high generality, even though of limited precision; it is far more valuable to be able to give ten- tative predictions over a hundred million acres than to predict accu- rately the course of events on a hundred acres. This means that ob- servational areas against which model results can be checked must be spread widely enough, and be numerous enough, to cover the variation over which generalization is intended. Moreover, the establishment of these monitored ecosystems for the purpose of validating models under development should be treated as a matter of some urgency. Their value largely depends on the period over which observations have been made, for long periods provide the most exacting test of models. There are a few sets of data already in exist- ence — largely collected by the U.S. Forest Service — extending back for decades; these are of the greatest value, even though only a limited range of variables was monitored. Field studies for the specific purpose of validating ecosystem models are also currently being set up under the International Biological Program. (See Figure IX-4) Many more such sets of data will be needed for the modeling work that lies ahead, and in each of them a wide range of variables should be recorded as a routine. Ecosystem Modeling — It would be premature to try to standardize ap- proaches to ecosystem modeling. The subject is not yet ten years old, and it is far too early to try to put it into a straitjacket. Several methods of modeling are presently under test; 283 PART IX — TERRESTRIAL ECOSYSTEMS Figure IX-4 — A MODEL VALIDATION STUDY Grams/ m- 40 ■— 36 32 28 24 20 12 4 - i FIELD DATA ■BHM SIMULATED DATA 160 200 1971— DAYS The graph shows the output of blue gramagrass biomass in g/m- as simulated by computer for the growing season of 1971. This simulation is one of the many outputs of the grasslands ecosystem model. Also plotted on the graph are actual field measurements of the blue grama production at the Pawnee site. Although there are differences in the curves, the over-all result indicates that the model is simulating the actual production. The differences can be explained, at least in part, by the fact that the abiotic variables that are an input to the model are not measured at the same location as the sampling point for the blue grama biomass. they should be given every encour- agement to develop independently (though with plenty of opportunities for contact) for some years to come. In the meantime, some new approach, not yet conceived, may well show itself superior to any. It is clear that modeling of abiotic parts of the ecosystem is considerably in advance of the development of submodels for the living components. More effort needs to be given to de- vising suitable forms for the latter submodels, and this will probably in- volve intensive experimental work on a variety of subjects. A good deal more thought needs to be given to the process of validat- ing models and comparing alterna- tives. Statistical considerations will clearly play an important part, but at present most statisticians avoid the subject. Techniques To Incorporate Diver- sity — Simplification is essential in the modeling of ecosystems; but the methods of simplification at present in vogue (in terms of compartments, trophic levels, and such) are unlikely to be the most fruitful. There is little doubt that the diversity of an eco- system is an important factor in its dynamics and stability, and means must be found to take this diversity into account in the model. The diver- sity or heterogeneity that is important may take various forms; first and foremost, the division of the biomass into species, each of which has dis- tinctive responses to the environ- ment and, consequently, distinctive niche requirements; second, variation within a species of genetic and ac- quired characteristics, including re- sponses to external factors and the timing of vital processes such as seed germination, metamorphosis, and reproduction; third, spatial dif- ferentiation and patterning, partly dependent on the inanimate substrate, partly developed through the dy- namics of the ecosystem itself. Such heterogeneity has mainly been incorporated in models by mul- 284 COMPONENT RELATIONSHIPS tiplying the number of distinct com- partments recognized; but this proc- ess cannot be carried very far. Until some more adequate technique is devised to deal with the various types of heterogeneity, the models devel- oped will be but a pale reflection of reality. Computers — Installations at the disposal of ecosystem modelers are often rather inadequate for the task. Modeling teams may be obliged to use rather slower machines, with limited storage, whereas ecosystem simula- tions are bound to be demanding both of space and time. Programming and model testing could be greatly facilitated by a shift from batch processing to interactive terminals, which are now available at few cen- ters. Digital computers are, in principle, far from ideal for the simulation of continuous processes. One would consequently expect a large hybrid computer to be appropriate for eco- system modeling; this may often call for an alternation of continuous and discontinuous operations, which could be performed, respectively, on the analogue and digital sections of a hybrid computer. Unfortunately, the programming of hybrid computers is at present far more difficult than that for digital computers, and facilities for remote-terminal programming do not exist. Hardware developments to meet this need are to be hoped for; in any case, it is important that the potentialities for ecosystem modeling of hybrid as well as digital computers should be fully explored. Interdisciplinarity — Continued em- phasis should be placed on the need for interdisciplinary training. Indi- viduals brought up within one of the traditional disciplines, with only limited and casual contact across the disciplinary frontiers, can contribute to a program in systems ecology only after extensive retraining, formal or informal. We need personnel with a broad training in the biological and earth sciences, who have developed expertise in certain aspects of mathe- matics and computer science. This is made more difficult by the rather narrow curricula of many universities. Energy Relationships in Ecological Systems Energy is essential for life, but since life itself is dynamic rather than static, energy flow must occur at all times. The earth ecosystem functions because of the flow of energy from a source, the sun, to a sink, outer space, after passing through the bio- sphere. The biosphere, which is that zone of soil, rock, water, and air containing organisms, is at an energy state, or thermodynamic level, that is compatible with life. This energy state is neither too warm nor too cold for life to exist and replicate. The thermodynamic level of the biosphere fluctuates greatly, with both random fluctuations and periodic cycles. Some portions of the bio- sphere (polar regions and upper troposphere or lower stratosphere) are relatively cold while other por- tions (tropical regions and thermal hot springs) are relatively hot. Nev- ertheless, life has evolved to occupy all of the earth's surface, some of the subsurface, and a good deal of the atmosphere. A part of our under- standing of the earth ecosystem and its many subsystems, including spe- cific biomes (see Figure IX-5), is to understand the passage of energy through the various components and the thermodynamic levels of each and every part. However, in order to understand and interpret the significance of en- ergy, of energy flow, and of a par- ticular thermodynamic state in the context of ecosystem analysis, one must understand simultaneously the life processes themselves. Ecology is that body of knowledge concerning the relationships between organisms and environment, organisms interact- ing with one another, and including the effect of man on the ecosystem. Ecosystems are those finite entities of the landscape which include the or- ganisms and the physical environ- ment. One must understand the physiological and biochemical re- quirements of each species in the ecosystem with respect to tempera- ture, energy, and such effects as photoperiodism, phototropism, and the like. The thermodynamic status of a plant or animal can be appre- ciated only in the context of its particular and specific physiological requirements. Life-Support Systems Primary productivity in the earth ecosystem is the result of photosyn- thesis. Each and every species of plant responds uniquely to environ- mental conditions — to the energy status, to gas concentrations of the atmosphere and water, to pollution, to disease, and so on. The entire food chain, web, or pyramid begins with primary production. A "natural" eco- system has many species of plants, each collaborating with the others to produce the total primary produc- tion of the system but each respond- ing in a special way to the variable conditions. Herbivores consume the plants and each herbivore responds to the variable energy status of the ecosystem in a unique way. Each species of herbivore will have its own physiological requirements and biochemical responses to temperature, light, moisture, gas exchange, pol- lution, and so forth. Energy is trans- 285 PART IX — TERRESTRIAL ECOSYSTEMS Figure IX-5 — MAJOR WORLD BIOMES I Tundra | Northern coniferous (Taiga), Temperate deciduous. and rain forest [>>i£] Temperate grassland [ 1 Chaparral and Desert § Tropical ram, deciduous, and scrub forest Tropical grassland and savanna, and Mountains (complex zonation) This map shows the distribution and location of the world's major biomes. Note that except in the rugged mountainous regions of North and South America, the distribu- tion of biome types tends to be along parallels of latitude. Such a situation suggests the importance of temperature and rainfall, both of which are strongly dependent on latitude. Studies of past climates and biome distributions also support this concept. ferred from primary producers to secondary producers, but the re- sponse of each herbivore depends on the daily and seasonal cycles of tem- perature, light, moisture, gas con- centration, and such. Carnivores and omnivores consume herbivores and primary producers to form higher levels in the food chain (see Figure IX-6), but again it should be empha- sized that each and every species responds in a unique manner to the energy state of the system and to cycles and fluctuations of energy, gas, minerals, moisture, and the like. Man is now affecting the life- support system of the planet earth to a serious degree. Man is consum- ing oxygen at a rate that may some- day change the concentration of this gas in the atmosphere, and at the same time man is affecting the pri- mary source of oxygen production through pollution and other means. Man is emitting to the atmosphere massive amounts of carbon dioxide (CO-); these directly affect plant productivity, since increased CO- in the atmosphere implies increased rates of photosynthesis. The in- creased atmospheric CO2 concentra- tions also imply potential changes of climate. The living, green, photosynthesiz- ing surface of the earth, with all its associated organisms, has evolved in synergism with the atmosphere. Each 286 COMPONENT RELATIONSHIPS Figure IX-6 — PLANT-MOUSE-WEASEL CHAIN SUNLIGHT 47.1 x 10* 46.5x10" -* GRASSLAND Grass Production Mouse Consumption Mouse Production >,170 - — 1,350 Import Mouse Population Increases 1,569 WEASELS Weasel consumption Weasel Population Increase 117 Decomposer Respiration Decomposer Production The diagram illustrates an actual energy-flow budget for a plant-meadow mouse- weasel food chain in an old-field habitat. Numerical values are in kilocalories per hectare. About 1 percent of the incoming solar energy is converted into plant tissue. Most of energy represented by this plant tissue is accounted for by respiration and decomposition. Of the remaining energy, the meadow mice consume only 2 percent. The weasels, in turn, utilize 30 percent of the available mouse biomass. Of the energy consumed in each stage of the food chain, the plants use 15 percent in respiration, the mice 68 percent, and the weasels 93 percent. This supports the suggestion that successive stages in food chains exhibit an increased utilization of the energy taken up. However, in this particular food chain, so little of the energy entering the system was eventually utilized in the conversion of weasel flesh that it would have been impossible for the habitat to support a secondary carnivore preying upon the weasels. Because of this tapering off of available energy in a food chain, food chains rarely exceed five steps and commonly have less. depends upon the other. The present composition of the atmosphere is the direct result of life on the surface, and life itself depends on the par- ticular character of the atmosphere. Ozone in the stratosphere, which screens the surface from the actinic ultraviolet rays of the sun, is a direct photochemical product of the oxygen that comes from plants. Carbon di- oxide and water vapor absorb and emit infrared radiation, thereby di- rectly affecting the heat balance of the earth, but these chemical con- stituents interact intimately with the green photosynthesizing surface. The atmosphere has a narrow semi- transparent spectral window that al- lows sunlight to flow to the earth's surface and some radiant heat to flow to space. It is this delicately balanced, unique system of life and atmosphere, in cooperation with the oceans of the world, which is the life-support sys- tem for man. Yet man persists in dirtying the atmospheric window and tampering with the energy flow, gas exchange, and life-support system itself. Energy Relations of Plants Energy exchange for plants is by processes of radiation, convection, transpiration, and photosynthesis. We now have excellent theoretical, math- ematical models to describe how a particular plant leaf is coupled to the climate surrounding it by means of energy exchange. The plant leaf will assume a particular temperature and a particular transpiration rate (the two dependent variables) as a func- tion of the total amount of radiation absorbed by the leaf, air temperature, wind speed, and relative humidity of the air (the four independent vari- ables). The plant's dependent vari- ables are coupled to the environ- mental independent variables by the absorptivity of the leaf to radiation, the size, shape, and structure of the leaf, and the internal resistance of the stomates to diffusion of water 287 PART IX — TERRESTRIAL ECOSYSTEMS vapor. We understand these matters well but still need much additional work in this area. It is the energy exchange for a leaf which drives all other processes critical to the life of the plant. The next part of the process, the gas exchange of carbon dioxide and oxygen release, is not well worked out. The chemical kinetics of photo- synthesis and respiration are rate processes which depend on light, temperature, and gas concentration and which are driven by the avail- able energy. In order to understand plant adaptation and response to cli- mate and environment, we must un- derstand the entire process of energy exchange, gas flow, photochemistry, thermochemistry, and physiological reaction. Each species of plant has a bio- chemical response which is enzyme- controlled. Some plants photosyn- thesize well at low temperatures and some at high temperatures, some at low light levels and some at high light levels, and so on. More knowl- edge is needed immediately concern- ing these enzyme-mediated processes. Schemes are needed to determine the basic biochemical response functions of chloroplasts and mitochondria within whole leaves as a function of leaf temperature, light intensity, and concentrations of oxygen and carbon dioxide. These measurements must be separated from the whole process which involves gas diffusion and the physical environment. The matter of photorespiration, which occurs in most plants, must be understood much better. We want to know precisely how it is that net photosynthesis productivity depends on the climate conditions of radiation, air temperature, wind speed, and hu- midity for each specific kind of plant. Only now are we putting together a complete model that incorporates in a self-consistent manner energy flow, gas diffusion, leaf morphology, anatomy, physiology, and biochem- istry. Such a model is essential if we are to understand primary produc- tivity, including the exchange of ox- ygen, carbon dioxide, water vapor, and other gases including pollutants. This is not only important for our understanding of ecosystems but also for our management of crops for food production. Energy Relations of Animals The energy budget of specific an- imals has been worked out for the first time only in recent years. From the particular properties of a specific animal we are able to predict the climate within which the animals must live in order to survive. Con- versely, for a given set of climatic conditions we can predict the met- abolic rate required for survival and this in turn puts limits on the avail- able food supply. Earlier work con- cerning the response of an animal to climate was highly qualitative and descriptive. (See Figure IX-7) Al- though useful, this is not sufficient, since we are dealing with an extremely complex response to a multiple set of variables all of which act simul- taneously. Our lack of good physiological knowledge for any particular animal is likely to be enormous. Informa- tion concerning metabolic rates, res- piratory moisture loss, evaporative water loss, and thermal insulation of animals is usually poor and inade- quate. This information is essential to an understanding of the energy balance of animals and their specific response to climate and environment. Figure IX-7 — ENERGY BUDGET OF A HORSE > INFRARED THERMAL RADIATION FROM GROUND The diagram depicts, simply and qualitatively, the multiple energy inputs and outputs that affect a horse. Although not quantified in the diagram, it is possible to describe each input mathematically so that the energy balance of the animal can be com- puted. The result can be used further as a part of a larger model describing the energy balance in a field or pasture where grazing takes place. 288 COMPONENT !■ \SHIPS Yet the ecosystem functions in the way it does because of the specific response of each and every animal in the ecosystem, the totality of which represents the food pyramid or web of life. Understanding of these mat- ters is critical to our understanding of climate and its effect on plant and animal communities of the world. Greatly improved physiological measurements of metabolic rates and water-loss rates as a function of environmental conditions are needed. It is necessary to know the values of radiation absorbed by the animal, air temperature, wind speed, and hu- midity during the course of any measurements. The conditions under which the animal was conditioned must be specified. In the laboratory, it would be particularly important that complete energy-budget analyses be done for each set of observations of the animal. In the field, careful observations are needed of metabolic rates and water-loss rates as well as of the microclimate conditions near the animal. These measurements are difficult to make, but must be done and can be done with the aid of telemetry and other modern methods. Systems Analysis On the one hand, mathematical analysis of the productivity of in- dividual plant leaves is now being done based on a holistic approach including the use of physics, chem- istry, physiology, and biochemistry. On the other, agronomists are work- ing out the energy and gas exchange of a community of simple plants — e.g., corn, wheat, or millet. A great deal of work is required to bridge the gap between these two ap- proaches. A given species has leaves that may occupy various parts of a plant canopy. The leaves forming one part of a canopy are in an en- tirely different microclimate than the leaves of another part, and the prop- erties of shade leaves are different from the properties of sun leaves of the same species. One can evaluate the individual leaves of each part of a canopy, apply the numbers game for all the leaves of a part of the canopy, and integrate over the entire canopy for productivity, respiration, total water use, and so on. This ap- proach will match up eventually with the approach of the agronomist to the problem of evaluating the whole stand. However, since the ecologist is interested in the role of various species within a stand, it is necessary to take this detailed approach. Competition and Phenology — The ecologist is interested in competition among the species of a plant commu- nity — competition for light, mois- ture, carbon dioxide, and nutrients, and maybe for wind and air flow, soil bacteria, and other factors. In order to understand competition one must understand the plant response to energy and gas exchange as they affect growth, flowering, seed devel- opment, and so on. A closely related topic is phenology — the response of organisms to time-cycles of climate. To understand phenology we need to understand the temperature of a plant as it responds to the climate of soil and air and to realize the significance of events throughout the season that may integrate into plant response. Studies of competition and phenology require good laboratory measurements and good field meas- urements. It is not so necessary to obtain an abundance of field data, however, as it is to analyze well and completely the field data obtained. Prediction — As we understand the specific response of animals to energy flow (radiation, convection, conduc- tion, evaporation, and metabolism), we can begin to work out the re- sponse of a set of organisms within a community. (See Figure IX-8) It is not sufficient to know the amount of energy transferred through the food pyramid from primary producer to primary, secondary, and tertiary con- sumers; it is also important to under- stand the energetics of each organism in the community and the response of each organism to all climate and edaphic factors. Furthermore, be- havioral studies of some animal pop- ulations often ignore or treat only cursorily the detailed environmental conditions. Animal behavior will of- ten respond to energy flow, as well as to other factors, in an intimate fashion. Despite an acute shortage of good physiological data for most animals, we can begin to simulate on the com- puter communities of plants and an- imals and their response to climate. We can set up simple experimental ecosystems in the laboratory or out- of-doors and check prediction from a model against observation. We need much better evaluations of en- ergy flow through various ecosys- tems, as well as evaluations of gas exchange and nutrient flow. The biome studies of the International Biological Program will add consider- able knowledge, but much remains to be done. Modern science has the capacity to do a much better job of analyzing energy flow through ecosystems and evaluating specific physiological re- sponse. Here is a magnificent oppor- tunity for a strong theoretical dis- cipline to be developed. It must be based on good physiological data from the plant and animal sciences. Theoretical development must be constantly checked by field observa- tions. 289 PART IX — TERRESTRIAL ECOSYSTEMS Figure IX-8 — RELATION BETWEEN FOOD INTAKE AND CALORIFIC EQUIVALENCE OF INVERTEBRATES Q O O 10» 5 2 10 ' LUMBRICIDAE ^^T •^r ORTHOPTERA« ^* DIPLOPODA ./^ • DIPLOPODA 5 ARANEA A 2 10" ISOPODA • J^RTHOPTERA ISOPODA • t^ ► ORTHOPTERA ICHYTRAEIDAE SOPODA «.^ ^ •isoDonA 2 10- ' ^^ ARAN - ^r ^ ^T • COLLEMBOLA ISOPODA • ^T ^r • ARANEAE 5 2 io-- ^f 5 Jf A P ACARIN 2 10 > vr • V\G ARINA io-= 10-' 10" 2 5 10' 2 5 log CALORIFIC EQUIVALENCE (cal indiv ') 10= The graph shows the relationship between food intake and calorific or heat equiva- lence of several invertebrates. This information was obtained from published material and synthesized to determine the mathematical relationship which then can be used in a numerical, computerized model to predict the amount of heat that is produced by a given amount of food. 290 A Note on Soil Studies COMPONFXT RLLATIONSHIPS Soil science in the United States is now scientifically stronger than ever before. Virtually each branch of the field is staffed with a sizable number of fundamentalists whose contributions are adding materially to an understanding of the soil sys- tem. Primary direction has been to- ward agricultural production, and results have been impressive. Labora- tories are generally well equipped with the most modern instruments. However, with each step toward increased specialization, we have fewer and fewer investigators who are capable of understanding in depth the entire soil system. Thus, we are developing more and more specialists working in highly technical corners with fewer and fewer investigators comprehending soils from the stand- point of the "field effect." Of course, this problem is not unique to soil science. Status and Needs In examining global soil resources, we find the subject fairly well docu- mented in the United States, Europe, the western sectors of the Soviet Union, and Australia. Through vari- ous international organizations we are getting a more complete picture of soil resources in other locations, such as Africa and South America; but even on these continents the picture is understood in at least gen- eral terms. Climate-wise, soil re- sources in the tropics, deserts, and the polar regions are not too well known. Strengthening the former two is more critical than the third, since congestion in the temperate climates is likely to bring increased population first to the desert sectors and then to the tropics, and only last, if needed, the polar regions. Water Quality and Quantity — Since water supply and water quality are of great importance not only for agriculture but for all of mankind, the major problem concerns the des- ert or desert-like areas. Water quality as well as quantity is related to cli- mate, substrate, soil, plants, and so on. The more arid the climate, the more acute the problem of quantity and natural quality of water. For example, drainage waters from desert areas are more likely to be charged with excessive salts for irrigation. Pollution and Soils — In the more densely populated areas (e.g., east- ern North America and Europe), the pollution problem is becoming acute. When potential pollutants enter the soil — whether they be industrial wastes, fertilizers, insecticides, or detergents, among others — we know very little of how they react. More emphasis should be directed to the study of organic matter, types of minerals, aeration, acidity, and so on, to learn how they affect the fate of potential pollutants. Stronger studies are needed on persistence adsorption, translocation, solution, and precipita- tion of potential pollutants in soils. If there is one area in which a team approach is needed, it is on the prob- lem of ecology and pollution. Wet Soil Areas — Since most po- tential pollutants entering the soil eventually find their way, in one form or another, to water courses, lakes, estuaries, coastal sectors, and the like, these locations are all materially affected. There are few soil and substrate studies being conducted in these critical low areas. Traditionally. our soils effort has been confined to farming areas and the growing of crops. Certainly, the problem of the soil system in low, wet areas and in the vicinity of lakes and shores needs to be strengthened. Soil classification in wet soil areas is weak; in general, little attention has been paid to these areas. Need for Balance Soil scientists are not now being used to full advantage in the United States. Virtually all ecological and environmental studies involve the soil system in some way. The soil is the link between the organic and inorganic worlds. But we see vir- tually all important soil research in this country being carried out under the aegis of agriculture, while soil studies dealing with ecosystems, a field currently as critical or more critical than agriculture, are poorly organized and poorly staffed. If we are going to master the pollution problems and problems of ecology and environmental control, then there must be a strengthening of undergraduate and graduate pro- grams in the subject of soil science in non-agriculturally oriented in- stitutions. Soil science should be programed — as are geology, hydrol- ogy, climatology, botany, and zool- ogy — as one of the natural sciences. It is not implied that the agricultural effort should be weakened; rather, the non-agricultural viewpoint should be strengthened. 291 PART IX — TERRESTRIAL ECOSYSTEMS 2. FOREST ECOSYSTEMS The Forest As An Ecosystem A forest is a natural or artificial vegetation unit encompassing many different tree associations and harbor- ing a multitude of other life forms which use it for food or shelter or both. Man has used the forest since his ascent to a dominant position, either for direct products or indirectly by destroying large areas and con- verting the land to other uses — mainly food production or urban de- velopment. Currently men consider forests and forest areas useful for the following purposes: wood and fiber production; forage production; water production; aesthetic values — with the many ramifications of this subject. In many instances, attempts to convert forests to other land uses have proved unwise, and large areas have gradually reverted to forest use or have been converted by planting of tree species; the species used were often different from the endemic populations and, therefore, the forest ecology has changed. Generalized Description of Forest A forest is best regarded as a system. As such, it is composed of subsystems, which can be defined in various ways, depending on the sub- ject under discussion. Here we prefer to consider two principal subsystems: (a) the abiotic, consisting of the non- living components of the soil on which trees and other green plants grow, the atmosphere surrounding and interacting with the living mem- bers of the system, and water and nutrient elements, which are in con- tinual movement through both biotic and other abiotic parts of the forest system; and (b) the biotic subsystem, consisting of living plants and an- imals. Trees are the dominant biotic fea- ture of forest ecosystems, constitute the framework of any structure it may possess, and affect importantly nearly all other components, biotic and abiotic. Shrubs, herbs, and non- vascular plants such as fungi, algae, mosses, and liverworts make up a smaller proportion of the total bio- mass of the forest system but play vitally significant roles in its dy- namics. Fungi and bacteria, for ex- ample, are the principal agents of decomposition, and all known tree roots function in symbiosis with my- corrhizal fungi in the uptake of water and nutrient elements. Insects, mam- mals, birds, and other animals are primary consumers of vegetational biomass manufactured by trees and other primary producers and, hence, affect the functioning of the system importantly; their numbers are af- fected by numerous predators and parasites. Where Science Stands Today To a large degree we are still in the descriptive stage of forest-eco- system understanding and, in some instances, not very far along in this stage. Most of the higher plants have been described and catalogued for most forests of the world. However, a multitude of other life forms exist and large numbers have not been identified; certainly their function is not understood, except for such com- mon forms as earthworms. The multiplicity of life forms exist- ing in forest soils is an example of the deficiency in our knowledge. As a more definitive case, if one looks at a tropical forest in detail one soon discovers that major spe- cies have been identified by indus- trious plant explorers but that our knowledge largely ceases at that point. Information on detailed inter- relationships, even those necessary to manage and predict the effects of common manipulations, is largely nonexistent in the case of tropical forests. For forests of temperate regions, which for the most part have been studied more by man and on the whole used more intensively, we presumably have better information. The complexity of our problems in these forests is reduced because spe- cies composition is simpler, especially as it relates to the dominant species. Thus, a northern coniferous forest may be almost a single-species forest whereas several hundred tree species may be found in a few square kilo- meters in many tropical forests. It is doubtful, however, that the same simplicity applies to all other life forms. In many instances, man has man- aged temperate and boreal forests rather intensively for relatively long periods of time to various ends — principally the production of wood. It is not surprising, therefore, that a considerable body of information has been built up relating to growth rates of certain important species in a given environment. In such cases, much is also known about the man- agement of water resources or the provision of forage for wild or do- mestic animals, and we have fre- quently acquired considerable prac- tical information on forest insect populations and diseases. Despite the relatively large amount of work on forests, the conclusions seem justified that much of it has been descriptive, on relatively small areas of a large forest resource, and so far has not materially enhanced our ability to make accurate predic- tions of important processes occur- 292 FOREST ECOSYSTEMS ring in forest ecosystems. For in- stance, we have no certain road to regeneration of a forest after natural or artificial removal, and many of the problems that develop in man- agement are still unpredictable. What We Need to Know An appraisal of present knowledge about forest ecosystems leads to the conclusion that we need to know more about the following subjects in order to understand these systems more thoroughly and make reason- ably accurate predictions. 1. Details of many life forms other than trees, especially those using the soils as a hab- itat; 2. Competitive aspects of forest life; 3. Dynamics of forest popula- tions; 4. Stability of forest environ- ments; 5. Forest growth and forest en- vironmental relationships; 6. Potential utility of different kinds of biomass produced in forests; 7. Total productive capability of forests with improvements man can add; 8. Aesthetic management of for- ests; 9. Method of coordinating and in- tegrating information collected on forests to answer some of the above questions and pre- dict results of forest changes — in other words, some kind of workable forest-ecosystem model. In a broad sense, lands devoted to various forest uses are considered to be within public control even though operated by private individ- uals. This seems to be particularly true of relatively large ownership, in contrast to the small acreages gen- erally referred to as farm woodlots. For example, game, fish, and recrea- tion are considered to be public goods on these private lands and, therefore, subject to some public control and management. In addition, of course, the United States is blessed with large areas of public forest land, managed by various agencies for a variety of purposes. In assessing the question of how research can do more for the public good in the management of these lands, we should probabl . look first at the purposes for which the land is to be used and the public good to be served. If a real public need is paper for education, or building material to improve housing of a large segment of the people, then one can make a logical argument for developing research programs that would make at least some of our forest ecosystems as productive in wood fiber as possible. On the other hand, if the best public need is served by setting aside most of the areas for recreational purposes, then we must develop pro- grams that would enable these lands to be used by large numbers of people but still maintain the recrea- tional and aesthetic aspect of the forest ecosystem. This is a more difficult task than most people realize and one which has had little investi- gation. For some reason, we have assumed that describing an area as a National Park or a Wilderness sets it up for permanent maintenance of its original state without undue prob- lems. In one sense, the problems imposed by large numbers of people on delicate forest ecosystems are more difficult to predict than uses for wood or water. Therefore, we must know enough about our forest ecosystems to set up the proper public use and then develop the information to manage them for that purpose. A Note on Hubbard Brook The study of interrelationships of forests, water, and minerals requires a special study vehicle that allows integration of information from sev- eral separate fields. As of now, re- search levels in the separate fields of forest soils and hydrology are reasonably adequate. Many forestry and conservation schools and federal and state agencies maintain person- nel and research facilities suitable to the study of these separate fields. But truly integrative research, which welds the expertise of various dis- ciplines and focuses it on a particular ecosystem, is relatively rare. The Hubbard Brook Study The Hubbard Brook Ecosystem Study was conceived and developed as a multidisciplinary study of single, well-defined watershed ecosystems, including both natural and man- manipulated ecosystems. The Hub- bard Brook Experimental Forest com- prises about 7,500 acres in the White Mountains of central New Hamp- shire, operated and maintained by the Northeastern Forest Experiment Station of the U.S. Forest Service. It is surrounded by a large, undis- turbed tract of the White Mountain National Forest, which consists of a series of discrete watersheds with similar northern-hardwood forest vegetation and a homogeneous bed- rock that forms an impermeable base. 293 PART IX — TERRESTRIAL ECOSYSTEMS The original goals of the Hubbard Brook Ecosystem Study were to un- derstand the energy and biogeochem- ical relationships of northern-hard- wood forest watershed ecosystems as completely as possible in order to propose sound land management pro- cedures. A small-watershed ecosys- tem approach was used to study hydrologic cycle-nutrient cycle inter- action in forest-stream-lake ecosys- tems. This concept provided an opportunity to deal with the complex problems of the ecosystem on an experimental basis. Integrated ecological studies of these small, watertight, replicated for- ested watersheds were begun in 1963 by Likens and Bormann in coop- eration with the U.S. Forest Service. The study has involved some 32 senior scientists from ten universities, one national laboratory, and three government agencies. The specific work ranges from studies of complete nutrient budgets, including measure- ments of inputs of cations and anions in precipitation and losses of cations and anions in dissolved and particu- late matter exiting the system, to studies of nutrient cycle-hydrologic cycle interactions, weathering rates, soils, litter accumulation and degrada- tion, biomass measurements, produc- tivity, nutrient turnover within the biota, phenology, energy pathways and relationships, and experimental manipulation (deforestation) of an entire watershed ecosystem. Figure IX-9 illustrates the results of one such study. In addition, a biogeo- chemical study of a small lake within the general drainage area of Hubbard Brook is under way. Computer simu- lation and systems-analysis proce- dures are being developed to facilitate understanding of the complex inter- relationship of these ecosystems. The results of the study to date have been described in numerous publications. The project has been endorsed by the U.S. National Com- mittee for the International Biological Program (IBP), and the study has been accepted as a part of the U.S. Figure IX-9 — ECOLOGICAL EFFECTS OF DEFORESTATION TRANSPIRATION REDUCED 100% EVAPOTRANSPIRA- TION 0.3X COMPLETE CUTTING AND HERBICIDE REPRESSION OF NEW GROWTH VELOCITY OF STREAM DISCHARGE UP, VISCOSITY OF STREAMWATER DOWN IN SUMMER RELEASE FROM INHIBITION BY VEGETATION? MICROCLIMATE WARMER, SOIL MOISTURE HIGHER IN SUMMER BIOTIC REGULATION OF EROSION AND TRANSPORTATION REDUCED OUTPUT OF STREAM- WATER 1.4X MOSTLY IN SUMMER ORGANIC MATTER TURNOVER ACCELERATED NITRIFICATION INCREASED 2.5X->100X ACIDIFICATION OF CATION EXCHANGE SITES CATIONS CATIONS ANIONS CONCENTRATION OF DISSOLVED INORGANIC SUBSTANCES IN STREAMWATER 4 IX OUTPUT OF PARTICULATE MATTER ca. 4.0X I NET OUTPUT— DISSOLVED INORGANIC SUBSTANCES 14.6X pH OF STREAMWATER 5.1 DOWN TO 4.3 TO DOWNSTREAM ECOSYSTEM The diagram summarizes some of the ecological effects of the deforestation of Watershed 2 in the Hubbard Brook Experimental Forest. The rates at which the processes are taking place are based on data obtained during 1966-68, and are expessed in terms of increases above those observed before the watershed was deforested. High nutrient concentrations, coupled with the increased amount of solar radiation, have resulted in significant eutrophication. This study is an example of how a known change in one component of an ecosystem can change the structure and function in another section of the same or related ecosystem in an unexpected way. program for the IBP and the Inter- national Hydrological Decade. The Value of the Small-Watershed Approach The small-watershed approach has already shown its power to draw together aspects of the fields of mete- orology, limnology, geology, soils, hydrology, biology, and ecology into one coherent study on the structure and function of an ecosystem. This type of approach is basic to advance- ment of knowledge of how landscapes really work. In turn, good land-use planning is dependent on knowledge of the structure and function of ecological systems. Although the hydrologic aspects of many types of watersheds, forested and otherwise, are under study, there are relatively few watersheds where comprehensive biogeochemical stud- ies are under way. This is a serious deficiency and should be remedied. Comparative small-watershed studies, where the watersheds are well de- fined, should be initiated in all major biomes where they are presently not part of IBP planning. Twenty to thirty of these studies scattered throughout the North American con- tinent in various biomes and involv- 294 FOREST ECOSYSTEMS ing undisturbed and man-manipulated ecosystems would be a modest start. Other Needed Activity Several other deficiencies are ev- ident when one considers comprehen- sive ecosystem studies. One of the major goals of ecosystem study is to improve our capacity to predict the behavior of ecosystems under various kinds of stress. Modeling, ecosystem analysis, and simulation of ecosys- tems are aimed at improving predic- tive capacity. Our capacity to meet these needs is growing haltingly, although there is a strong need for a centralized laboratory dealing with the mathematical aspects of ecosys- tem analysis. This lab could do research on its own and cooperate in modeling, analysis, or simulation of various ecosystem studies under way or planned. One of the great problems facing teams of scientists ana i forest (or other ecosystems) is physical and chemical analysis of thousands of samples of plant and animal tissue, air, water, soil, and the like. Service laboratories charged with these types of analyses and with the develop- ment of new sampling techniques would be of great utility in accelerat- ing and expanding studies of the many terrestrial and aquatic ecosys- tems that make up the continental United States. Tropical Forests Tropical forests now cover about 5 billion of the approximately 10.6 billion acres of the world that are still forested. These forests are among the most poorly known areas of the world, especially with respect to their ecology. This condition is particularly unfortunate because there is no other system with comparable productivity that covers more than a small fraction of the area occupied by the tropical forests. Because of our ignorance, these forests remain one of the most poorly used of the earth's resources. General Description of Tropical Forests and Soils Evergreen "tropical rain forest," the most productive of the tropical forests, is found in the lowlands where rainfall is high and where dry periods, if they occur, are very short. Evidence suggests that the forest itself appreciably increases its own rainfall through the water that evapo- rates from its canopy. Semi-decidu- ous and deciduous forests are found in areas with high humidity but dry seasons of several weeks to months. Dry seasons of several months permit development of a continuous, but relatively dry and less well-developed, forest; if dry seasons are longer, forests can exist only as patches, small groups, or single trees separated by grassland. The adaptive characteristics of tropical forests (and the problems from man's point of view) are largely the result of interactions between the rather uniformly high tempera- tures and the amount of rainfall. The physical character of most tropi- cal soils is such that both water and air can move through at least the surface layers relatively easily; thus, as long as the forest canopy is intact, rainfall does not cause much erosion. In over half the tropical land area, however, heavy precipitation has re- sulted in the solution and leaching away of almost all but the most resistant oxides of iron and alu- minum. Where leaching has been extensive, availability of plant nutri- ents and soil fertility is generally very low. Tropical trees are successful under these conditions largely because they have developed efficient mechanisms for nutrient cycling. This is accom- plished by the shallow root systems, which acquire minerals as fast as they are released from fallen leaves and branches during their rapid de- cay. Thus, the few minerals obtained from the soil and the rain per unit of time are not allowed to escape. Because of the efficiency with which minerals are captured following their release through decomposition of dead organic matter, the amount of minerals tied up in the vegetation frequently rivals — and for a few elements exceeds — the amount in the soil. (Even so, productivity of many tropical forests is limited by lack of some mineral nutrients; dis- covery of effective methods of pro- viding more of these minerals could greatly improve forest production.) Nutrient availability is higher in some of the younger volcanic soils scattered throughout the tropics be- cause there has not yet been time for complete leaching to take place. Some of the relatively shallow soils on steeper slopes are also richer than the deeper soils on level areas be- cause erosion keeps sending the most leached soil down the slope, permit- ting tree-root systems to penetrate to newer soil formed from the parent rock below. By temperate-zone stand- ards, however, even these relatively rich tropical soils are often of low fertility. Land Management in the Tropics Traditional native practice in tropi- cal forests is to cut some or all of the trees in a small area and then to burn them. Nitrogen supplies are 295 PART IX — TERRESTRIAL ECOSYSTEMS lost by this slash-and-burn method, but the ashes contain the other min- erals that had been held by the trees and thereby provide enough fertility for one or more years of primitive crop agriculture. After several years, so much of the mineral has been leached away that the land becomes too poor to crop and new land must be cleared. In some slash-and- burn techniques, additional trees are brought in (especially from the slopes) and burned on the cut-over areas along with the normal slash; crop production can then continue somewhat longer than usual because of the increased amount of fertilizing ash provided. In some areas, it is necessary to maintain a cover on the soil at all times if the lateritic soil is not to be destroyed by the combined effect of direct rain and sunlight. Shifting cultivation (slash-and- burn) techniques can work well enough to support low populations, but they require a great deal of land. Five to fifteen years of forest fallow are needed to allow rebuilding of the trees' mineral supply; this means that, at best, several times the area cropped must be available in order to provide continuous support of a farmer. Modern Techniques — In general terms, the methods of increasing yields are the same in the tropics as in temperate areas. Nevertheless, attempts to transfer temperate-zone ecology and agricultural practices di- rectly to the tropics have usually met with failure, occurrences which emphasize how much we have yet to learn. Techniques of replacing slash-and-burn methods with care- fully designed crop rotation (fre- quently including care to maintain continuity of a canopy) are now being developed. They show some promise, but a great deal more re- search is needed. Fertilizers can be very effective, but poor understand- ing of soils and of plant requirements means that the kinds and combina- tions of materials that would be most useful on each are unknown. Re- quirements and effective methods of application are generally not known for major nutrients or for trace ele- ments. Water-conservation (and erosion- inhibition) devices such as bunds, terraces, mulches, tie ridges, and so on are useful. Irrigation can be very effective, but there are usually un- considered costs associated with the use of dams and reservoirs. Perhaps the most important of the latter is the effect that dam-associated flood control will have on downstream lowland alluvial soil such as those along the lower Nile. Fertility of these soils has remained high, some- times in spite of millenia of intensive farming without fertilizers. This is because of the annual natural mineral input of the deposited flood silt. Comparative costs of maintaining fer- tility of these alluvial soils in the absence of flooding are unknown. Rebuilding Degraded Soils — If much produce (lumber, crops, etc.) is to be removed from an area, this will remove the nutrients incorpo- rated in the produce. Where the nutrient cycling is tight, as in tropical forest, crop removal can result in spectacular fertility-loss rates. Even if all the unused parts of the plant are returned to the mineral cycling, the fertility of the soil will decrease. Techniques need to be developed to replace these losses from crop re- moval and mineral leaching and to learn how to provide additional min- erals so that production can be in- creased. For example, many tropical soils have properties that are espe- cially effective in the making of added phosphorus and some trace min- erals. The extent of forest in many parts of the tropics, especially in the dryer areas, is being reduced by fire and by overgrazing by domestic stock. Grasslands are replacing forests and, partly because grasslands have less close minerals cycling than forests, the quality of these soils is being degraded. (See Figure IX-10) Activi- ties of man and his stock have already produced large areas of white-sand savannah which have very low pro- ductivity. Even if the influence of man and stock were removed, re- forestation would be slow because the soils have been so greatly damaged. Efforts must be made to learn how to counter the soil-degradation processes that have produced these areas and how to rebuild the soils that have already been degraded. Forest Management for Production Timber — Although tropical areas contain almost half of the world's forests, they produce only about one- tenth of the world's timber. Only about one-sixth of the tropical forest is being exploited for timber, in part because of the inaccessibility of about 60 percent of the forested acres. There are several reasons for this: lack of road networks and vehicles; poor markets, which means that building roads and buying vehicles for timber harvest is uneconomical; low levels of available technology; the fact that many tropical hardwoods are so heavy that they will not float, thus precluding use of rivers to float logs as is common in the higher latitudes; and the diversity of tree species usual in tropical forests. This diversity means either that many kinds of timber must be cut and marketed or that a great deal of effort must be expended to extract only the few species desired from an extensive and highly varied forest. Much research needs to be done on these problems. If clear cutting is practiced, or even enough trees are taken that the integrity of the canopy is destroyed, soil destruction can oc- cur and erosion may be severe. In some parts of the tropics, soil will, in effect, turn to stone when so ex- posed. In other areas, siltation from erosion following timber extraction of forest clearing has produced se- rious problems. For example, silta- 296 FOREST ECOSYSTEMS ORIGINAL WOODLAND- evapotranspiration continuous greater part of year Soil at Field Capacity ajsrasggggga W ^-?: i-V ,>!> 'X^'t'" - *-,*£,? ^^■'*^^#s'*^^'' ILayerof Saturated Soil 'lllllllllillilllllllllllllllll/lllllll/llililllllllli/, i Impermeable Layer* I The illustration shows the differences between a forested area and an unforested one in Rhodesia. In the forested area, the depth of soil and amount of water are sufficient to support the growth of trees. Evapotranspiration (a combination of water loss by evaporation from the soil and transpiration from plants) is in balance with the available water supply. Once the tree cover is removed, evapotranspiration is reduced, thus allowing the water table to rise and reducing the depth of usable soil. The net result inhibits crop growth. tion following poor forest-utilization practices has greatly decreased the life expectancy of reservoirs; it some- times causes problems by silting up irrigation channels and often reduces efficiency and causes damage to pumps through clogging and abra- sion. If the silt can be deposited on the cropland, it provides fertilization (but at a high cost). Research needs to be done to find out how best to crop the timber of these forests with minimal damage and promotion of minimal forest-regeneration time. The relatively little developmental work that has been done on intensive management techniques to increase the timber yield of tropical forests suggests that it will be possible, with more understanding, to raise produc- tivity to at least three times present natural levels. Under some circum- stances, natural productivity may be surpassed by twenty times — or pos- sibly even more. Much research will be required, however, if this goal is to be reached. Tree Monocultures — Biological mechanisms that operate to control populations of various plants and animals appear to be more prevalent and more effective in the tropics than in temperate and arctic zones. The high diversity of tropical forests may, in part at least, be a response to this condition. When attempts are made to grow monocultures of various tree species or other crops, therefore, tropical populations may be subject to particularly severe bi- ological attack. For example, it has so far proved impossible to establish successful rubber plantations in South America, the home of the Para, or hevea, rubber tree, because of disease problems. Under natural con- ditions, where rubber trees are widely scattered, disease is transmitted poorly because of the distance be- tween trees. The biological attack that many tropical monocultures suffer can be blunted or stopped in some instances, but the problems are frequently se- vere and a great deal of good research is needed for their solution. The problem has been partly overcome (or avoided) for some species by transporting them to parts of the tropics in which they are not na- tive — with great care taken not to transport simultaneously their dis- eases or insect pests. The highly productive rubber plantations in Af- rica and Southeast Asia, for example, were started with South American trees. This technique can doubtless be useful in the future, but it is of paramount importance that careful, thorough, and appropriate research precede it. Inadequate research could lead to release of species in areas where, in the absence of their natural biological controls, they would spread to become pests of major magnitude. This could produce a catastrophe that would dwarf the disaster that fol- lowed the release of prickly-pear cactus in Australia. By 1900, this cactus covered an estimated 10 mil- lion acres, and by 1925 it had spread to about 60 million acres; in half of this area, the cactus was so dense that neither man nor horse could enter. Looking to the Future Genetic breeding programs for most tropical plants, with a few out- standing exceptions, are not well developed or are not being carried on at all. With respect to forest trees and their yield, enough has been done with a few temperate species to dem- onstrate that programs of this kind can be of great benefit in increasing yield and decreasing inter-cropping interval. Tropical-tree yield can doubtless be greatly increased as well, and research and breeding pro- 297 PART IX — TERRESTRIAL ECOSYSTEMS grams should be greatly increased. An obvious problem is that breeding programs with trees progress slowly because of the amount of time re- quired for trees to grow to the point where they can reproduce. Because of their high productivity and even higher potential it might be possible to develop tropical for- ests as a major new food source. For example, leaf extracts of a number of species have a high protein con- tent and large amounts of digestible carbohydrate. Research is needed to determine the best methods of leaf collection and food extraction and how to handle the disagreeable aro- matic, gummy, or other substances that are often produced by tropical trees. Additional work will also be needed to determine how to package, advertise, and sell these products. Traditional food habits of most peo- ples are hard to change, even when such change could result in a distinct improvement in their nutrition. Some tropical trees have useful pharmacological properties. About half of the new prescriptions cur- rently written contain one or more plant products as a major active in- gredient. The tropics have been an especially rich source of these chemi- cals and there is no doubt but that further investigation will be very rewarding. Several other problems should at least be mentioned. One has to do with the use and misuse of resources provided by animals of the tropical forests in the form of meat, hides, pets, and experimental animals. An- other relates to the reservoir of dis- ease, disease vectors, and pests pres- ent in tropical forests. A third results from the interaction of vegeta- tion and the hydrologic cycle and on the effects of irrigation, each of which can produce appreciable effects on local (and perhaps distant) rainfall amounts. A fourth concerns the ef- fects of wartime defoliation on large stretches of forests and the problems involved in providing for their rapid recovery (or the development of really good alternative uses of the affected areas). Although it may not now be much of an immediate problem, the rate at which air pollution is increasing could pose a serious problem to parts of some tropical forests. As a result of efforts of many of the less developed countries (which are primarily tropi- cal) to industrialize, local air pollu- tion may increase rapidly. Many of these countries may be too poor to be willing to pay for unprofitable pollution-abatement programs and processes. A possible longer-term problem is related to the fact that tropical species generally are more sensitive to tem- perature fluctuations than are tem- perate species. This means that if man's various activities should cause either a warming or, as now seems more likely, a cooling of the climate, the tropical forests could be in real trouble. Removal of these forests could itself contribute to this cooling through resultant increases in albedo and in atmospheric dust. In either event, a useful ecological generaliza- tion is that species from stable en- vironments (as in the tropics) are more sensitive to temperature and chemical effects than are those from fluctuating environments (as in tem- perate zones). Finally, because of the magnifi- cence and complexity of the biologi- cal system that is represented by tropical forests, they will serve as excellent resources in the develop- ment of man's understanding of the ecological enterprise and as an area to which he can go for rebuilding and refreshing the human spirit. Efforts should be made to preserve parts of these forests, and to make them readily available for these purposes. Comparison of Temperate and Tropical Forests Whether we like it or not, feel it dangerous or laudable, the human race must prepare itself for a gigantic task: managing the earth's surface! This task is not, of course, the con- cern of any single nation or race, but it is obvious that the highly in- dustrialized nations of the northern hemisphere must take the lead in tackling the job before us, because they have the economic wealth, sci- entific manpower, and industrial force to begin to undertake the task. It is natural that we, as a people of the temperate zone, take our own environment, the deciduous forest or grassland biome, as a reference point in trying to understand other terres- trial environmental features. This way of thinking is sometimes dan- gerous, especially if we try to draw conclusions from management prac- tices in one area and transfer this concept to another. For present pur- poses, however, it is valuable to start from a few principles common to all productive areas of the world and elaborate the differences from these. The State of Scientific Knowledge The temperate zone has at least three very distinct forest formations in which the ecology, especially the sensitivity to human impact, is en- tirely different: deciduous forest; chaparral; and laurel forest. Tropical areas are even more complex in this 298 ^TEMS respect. One can distinguish among lowland tropical or equatorial rain forest, subtropical rain forest, sea- sonal forest, forest savannah, and tropical mountain forest. These for- est types all have some common and some unique features, which do not clearly separate themselves into tropi- cal or temperate; for example, ever- greenness appears in both regions. A selection of compositional, struc- tural, and functional criteria are com- pared in Figure IX— 11. Here, the dis- cussion will center on comparisons between temperate deciduous forests and tropical rain forests. Although we know a great deal about the properties of almost all existing vegetation types, we seem hopelessly confused about how much of each vegetation type exists in the world. The terminology for distinct types is weak, and the accounts of different authors conflict. Even in such apparently clear traditional groupings as forest, grassland, desert, and cultivated land there are many discrepancies about areal extent. Total land surface is always the same, of course — 147 million square kil- ometers. But statistics for various vegetation types gathered within the past fifteen years, including the offi- cial calculations of the Food and Agri- culture Organization, vary greatly. Thus, one can find the following estimates: Figure IX-11 — COMPARISON OF TEMPERATE AND TROPICAL FOREST 1 Land Type Square Kilometers (millions) Forest 38-50 Boreal Forest 12-23 Tropical Forest 15-20 Grassland 24-40 Tundra 6-7 Desert 14 Cultivated Land 14-17 a. Properties Predominantly evergreen leaf cover (yes or no) Height of stand (feet) Approx. leaf area index x ground surface covered Coniferous species present Functional annual sea- sonality (yes or no) and ruling force temperate deciduous no > 100 ~ 10 rare yes; forest temperature chaparral yes <100 5-12 present yes; temperature + rain laurel forest yes < 100 9 rare yes; temperature lowland tropical yes > 180 3-11 absent no rain forest subtropical rain yes > 120 8-15 rare yes, weak; forest rain seasonal forest yes/no > 100 10-22 rare yes; rain forest savannah no < 100 ? absent yes; rain + temperature tropical mountain yes <100 2-8 variable no forest ra re to present The table lists several properties of forest types and compares these within the temperate and tropical zones. Note the importance of temperature in the tempera- ture zone and that of rain in the tropics. Discrepancies are even greater with respect to subdivisions of the above- mentioned formation classes. Such uncertainty offers a weak basis for world management planning. A new plan must incorporate the evalu- ation of a new size inventory for whatever the management units might be. These units are fairly easy to establish along the biome concept, which coincides generally with the "zonal vegetation," "climax vegeta- tion," or "vegetation formation" of the phytogeographers. Classical Models — Any manage- ment plan requires a model. The "models" of the ecologically oriented phytogeographers have traditionally included the following categories: (a) altitudinal profile; (b) soil pattern and catena; (c) climatic (microclimatic) pattern; (d) species composition; and (e) successional series. The correlation between some of these properties is so significant that predictions can be made in the tem- perate zone and, to a lesser extent, in the tropics. The predictions are usually more reliable for plants than for animals; they are usually better for qualitative statements than for quantitative statements; and they are normally better for dominant species or factors than for the less important components. In the deciduous forest, the traditional models are already re- fined and commonly used for manage- ment practices. In the humid tropics, they are generally an order of magni- tude cruder; some are just being elab- orated. A generalized model of a suc- cession, including productivity data, is impossible to draw for the humid tropics with any degree of confidence. Knowledge of tropical and tem- perate-zone ecology is about equal almost everywhere. However, knowl- edge in certain geographical regions or with regard to certain factors may be more advanced in the tropics, and 299 PART IX — TERRESTRIAL ECOSYSTEMS the knowledge gained there shows reverberations and applications in the temperate zone. Mathematical Models — Modeling in the sense that it is used today with regard to systems analysis — i.e., mathematical or computer modeling — exists for partial processes in many cases in the temperate forest area, only rarely in the tropics. No entire ecosystem is yet completely under- stood and modeled in any biome. This work is just now being under- taken by several thousand ecologists working in different parts of the world. The Analysis of Ecosystems Pro- gram of the U.S. International Bio- logical Program has as its ultimate goal to provide the next generation of scientists with an ecosystems model that gives a satisfactory approxima- tion of the following structural and functional characteristics of the vari- ous terrestrial ecosystems: (a) pro- ductivity range; (b) turnover rates of matter and nutrients; (c) species di- versity; and (d) environmental pa- rameter ranges with special emphasis on energy, temperature, water and substitute levels of nitrogen, phos- phorous, potassium; and others. Fur- ther, the program will help us to secure sufficiently accurate data for the elaboration of a general ecosys- tems model that enables us to predict functional and structural responses of any given ecosystem to man-made or accidental changes. It will take several more years of intensive study to develop predictive models for population changes and chain reactions caused by the elimi- nation or introduction of species or groups of species. These "sensitivity investigations" may provide the most important results from present eco- systems studies. In many cases, changes are surprising and significant but apparent only after several years. It might be easier and quicker, there- fore, to study the effects of some interferences in tropical environments her than in temperate zones, be- cause development periods are shorter and uninterrupted by a rest period. Genetic studies have applied this principle successfully in many cases, and ecologists should do the same. The results of such studies in tropical areas will provide us with models that will help us to manage our own envi- ronment, especially in the southern United States. For some of the large-scale changes that man imposes upon the environ- ment, predictions are already possi- ble. Thus it is probably safe to predict that, in South America, large-scale traditional (temperate-zone) agricul- ture in the Amazon-Orinoco water- shed will fail, that the Rio Negro region will change from a black-water stream to a white-water system, that all sorts of unpredictable changes in the fauna will occur as a result of the removal of several natural environ- mental barriers, and that fantastic changes will follow in every respect. It is probably unsafe, however, to predict what would happen to the atmosphere if all the tropical regions of the world were cultivated. The data base is too slim for any reason- able prediction. We can only define certain areas that are likely to become problems: for example, the change of tropical air masses from an almost constant carbon dioxide level to an as yet unpredictable fluctuation; or the potential threat of airborne dis- ease originating in the tropics (espe- cially fungal diseases of plants) for plants, animals, and man. The at- tempt to establish large human settle- ments in the humid tropics of South America raises problems of unknown magnitude. For example, sanitary sewage disposal in an area saturated with water and at such a temperature level is a gigantic problem, and the prospect of industrial sewage is even more dire. Needed Scientific Activity The primary reason that ecology was previously the "Cinderella" of the biological sciences is the fact that an incredible number of species are ruled by an unwieldy number of forces, and the species in turn influ- ence the forces. The analysis of an ecosystem always seemed an unman- ageable task, even assuming that only the most important components were to be studied. The recent develop- ment of systems analysis, the teach- ing of team studies, and the ever growing computer capacities give us a more realistic chance for a valid ecosystem model. But all these tools are useless without a willingness of many scientists from several disci- plines to cooperate in one study and generate the necessary data pool for individual cases. Data Base — The data base for the prediction of human impact is com- pletely incomparable in deciduous and tropical forest areas. From the standpoints of an ecosystems mod- eler, the data base is totally lacking to unsafe or, occasionally, satisfactory in tropical areas and sometimes suffi- cient to unsafe in the deciduous forest areas. A general judgment is not possible because the knowledge nec- essary for the understanding of eco- systems is so different in the various disciplines. It is still necessary to conduct major investigations and col- lect a sound set of data if one cares about accurate models that are mean- ingful for management purposes. Instrumentation — The sensors and techniques to acquire the necessary data are generally adequate, though their reliability and durability are usually better in temperate zones than in the tropics. It is, of course, always necessary to develop new tools for the constantly changing tasks before us. For the elaboration of better and more complete ecosys- tem models, we foresee the need for simulators and analogue computers of larger dimensions. Many computing facilities today still have only the capacity to confirm the conclusions that people had drawn from hand calculations. How quickly progress will be made naturally depends on 300 FORES I the demands of scientists and the adequacy of public support. Ecosystem Models — The develop- ment of ecosystem models is pre- requisite to an adequate understand- ing of environmental problems. A single model is infeasible at the mo- ment, but we see this as a future goal. The development of a set of models is the immediate necessity as a base- line for application in both manage- ment and teaching. The set of models to be developed needs to include all of the classical models mentioned earlier, but better quantification is needed for many pa- rameters. Tropical areas need much more work for the elaboration of such models than temperate zones. Spe- cifically, the following sets of models — in the form of abstract mathe- matical equations, matrices, or proba- bilistic or stochastic statements — are needed for understanding and pre- dicting human impact on the bio- sphere or environment: 1. Global Level (a) Production capacity of vege- tation; responses to average levels of growth factors like radiation, temperature, wa- ter, nutrients, pollutants; utilization of vegetation by animals and man; (b) Optimal carrying capacity of the earth for men under various possible manage- ment practices; (c) Interaction of vegetation and the physical environ- ment; circulation of carbon, oxygen, and other sub- stances through atmosphere, biosphere, hydrosphere, and geosphere; quantity and rate (circulation speed) need to be investigated. 2. Biome Level (a) Production rate of vegeta- tion; (b) Utilization practices of ani- mals and other consumers; (c) Decomposition rate; (d) Reasons for homeostasis and the equilibrium level of forces that maintain it; (e) Efficiency of energy utiliza- tion; (f) Man's management prac- tices and their influence on the system's turnover rates. 3. Regional (Landscape) Level (a) Production, consumption, and decomposition in bio- cenoses; reactions to levels and specific fluctuation pat- terns of external and inter- nal forces like radiation, temperature, water, nutri- ents, pollutants, animal feeding, etc.; (b) Developmental patterns of species in space and time; (c) Qualitative responses of the regionally available species pool with regard to different environmental matrices; (d) Chemical diversity within the food web. Such a model can only be developed if comparisons are available from all contrasting biomes, although some biomes are more important than others for the development of a gen- eral model. For example, inclusion of a humid tropical forest is essential, since these forests represent either the absolute maximum, optimum, or minimum realized on earth for many of the ruling environmental forces. Turnover of matter and energy in the humid tropics is twice as fast as in the temperate area. Tropical areas contain at least 60 percent of the world's natural resources. Again, the humid tropics are especially suscepti- ble to human impact, since their soils and climate and orographic conditions are highly sensitive. This is especially true for modern agricultural tech- niques, utilization of high-yielding varieties, and constant shielding with pesticides and insecticides. 301 PART IX — TERRESTRIAL ECOSYSTEMS 3. FOREST ANIMALS Problems of Animal Ecology in Forested Areas Traditionally, the study of animal ecology in forested areas of the United States has been concerned only with species that are either in- jurious to man or to forests or are game animals of interest to the hunter. To these original concerns — i.e., the impact of animals on the forest and the availability of animals for man — we should now add two more: (a) the impact of man on forest animals, and (b) the needs of forest animals for suitable habitat. Large and small forest animals and birds affect man's aesthetics, eco- nomics, and, occasionally, his health. Furthermore, the greatly increasing pressure of man on the wildlife re- source of the forests has created seri- ous problems. Sometimes control of animal populations is necessary or desirable; this is true in the urban- suburban fringe as well as in na- tional parks and private recreation areas. At other times, the need is to promote the integration of forest wildlife into the urban and semi- urban scene, where the presence of wildlife provides an antidote to some of the stresses of urban living. The State of Animal Ecology Research Forest animals vary greatly in their adaptations, both to the type of forest and to the relative amounts of forest and open land that they require. Many forest animals are more accu- rately forest-edge animals; the white- tail deer is a prime example, and any consideration of white-tail habitat must involve the relative proportions of forest and opening. In addition, year-to-year differences in environ- mental conditions may have drastic influences on the animals. The im- pact of winter weather on the survival of the ruffed grouse is a case in point. Low temperatures, snow depth, and the conditions of the surface of the snow all play a part in the survival of the bird: that is, ruffed grouse can survive long periods of extreme cold provided that adequate snow is avail- able and uncrusted, so that the bird can penetrate into the snow for night roosting. With deer, light snow per- mits ready movement but deep snow restricts it. Similarly, environmental differences between locations influ- ence the behavior, feeding ability, and survival of an animal population. Data Base — A reasonably ade- quate base of data on forest animals already exists. This is particularly true for those animals important to the hunter and sportsman, such as the white-tail deer, ruffed grouse, wild turkey, and gray squirrel. Data are gradually accumulating on the life histories and behavior of various car- nivores, including the black bear, bobcat, coyote (in forest habitats, especially), and timber wolf, as well as on many smaller mammals, both predators and herbivores. Knowledge of gross food supplies for forest herbivores is readily avail- able, but more important are the data now being gathered pertinent to the calorie content of this food and to the fluctuation in mineral constituents — i.e., on the quality of the animals' food. Much data have been accumu- lated on browse for white-tail deer, lesser amounts of information on fruits and nuts. But there are sizable gaps in our understanding of the utilization of food and shelter. Little is yet known of the reasons why certain plant spe- cies are consumed in preference to others, nor are the changes in rumen flora of the white-tail deer under- stood. Virtually no information is available on forms of food materials like forest herbs and aquatics. We are just beginning to discover some of the nuances of the summer food habits of deer, the diversity of foods used (particularly herbaceous mate- rials), and the impact that summer food selection may have on deer habitat. Additionally, although we know that crossbills and finches use seeds of forest trees in quantity, we know little of the relationship of these bird populations to tree seed crops. Food selection, utilization, and availability are thus areas open to considerable work relative to most forest animals and birds. Instrumentation — The advent of radio telemetry has done much to in- crease knowledge of the home range and behavior patterns of a number of animals and birds. For example, movement patterns of owls have been studied in Minnesota and the hunting pattern of barred owls delimited. (The owl hunts in one area until prey populations have dropped — i.e., un- til hunting is unprofitable; it then moves on to another location and another and in time returns to the original spot when mice populations have again reached a suitable level.) Telemetry is also producing informa- tion on deer behavior as well as movement patterns for such animals as the grizzly bear and the timber wolf. The impact of radio telemetry on knowledge of animal behavior is al- ready great, but there is ample room for additional studies of movement patterns and even more opportunity for telemetry of physiological param- eters. Improvements are presently being made in the technology, and much information of value will likely be gained thereby. 302 FOREST ANIMALS In the field of habitat research, progress has also been made in im- proving sampling methods. Low- level, large-scale photography offers excellent opportunities for improving the analysis of wildlife habitat. Modeling — Mathematical model- ing has already shown some value and will undoubtedly be useful in clarifying many animal-habitat rela- tionships. Theoretical formulation of data in forest animal ecology has been relatively slow in developing, how- ever. The lack of suitable quantita- tive input has been one deterrent; another has been the slow develop- ment of modeling techniques. Needed Scientific Activity Habitat Research — The single most essential need in forest wildlife ecology is to relate or link the animal to its habitat in detail. Although con- siderable data are available, the link- ages are still far from clear. For example, what is the relationship between food availability and con- sumption, or between tree cover and energetics. Specifics are needed on the interaction of animals with abiotic environmental factors as well. Answers to such questions will re- quire both additional field studies and the use of mathematical models that can in turn be tested for accuracy by field investigation. They will also re- quire greater interest on the part of researchers themselves. In the Lake States, for example, despite the great importance of forest wildlife to the recreation industry as well as to the health of the forest ecosystem, very few individuals are engaged in forest- habitat research. With suitable additional input, con- siderable advances could probably be made within fifteen years in the link- ing of animal to habitat components - both food and shelter. Steady progress toward this end is highly de- sirable. Population stress and its un- derlying causes is another area of work that deserves attention. The study of animals as disease vectors, although not a major problem area, should be continued. Public Understanding — Despite re- maining gaps in scientific understand- ing, present knowledge of the ecology of the larger forest animals probably exceeds the ability of the land man- ager to use this information. Today's land manager is restricted by lack of popular acceptance of the basic prin- ciples of population dynamics and habitat. Like religion and politics, questions having to do with length of hunting season, bag limits, and status of animal and bird populations are not easily settled; nor are they always discussed rationally. For example, it is difficult to con- vince the public that changes in habi- tat and weather are usually much more effective in population control than is the two-legged predator. Thus, controversy always surrounds the question of whether or not female white-tail deer should be hunted. And yet the known reproductive cycle of the white-tail, its responses to weather conditions, the effect of severe winters on reproduction, and the normally high replacement rate all indicate that it is virtual! sible to exterminate deer save on a very local basis. Other fallacies in- clude (a) the idea that it is possible to "stockpile" populations of ruffed grouse by closing the season one year and thus have more birds the next, and (b) the concept of predator con- trol by bounty. Perhaps for these reasons, the Great Lakes Deer Group several years ago listed public understanding as among the most important of its problems; the group recommended motivational research to find out what creates public attitudes toward agency programs, a study that should include the sociology and psychology of deer-hunting and other factors re- garding the deer herd. In general, the most controversy results from a lack of understanding by a major segment of the public of the ecologi- cal requirements for animal devel- opment and of animal population dynamics. One may say with reason that there are no strictly scientific controversies in forest animal ecology, although there is some disagreement as to the relative impact of habitat and preda- tors on populations of certain game animals (specifically, the moose at Isle Royale) and on deer in the Middle West and elsewhere. The scientific base of understanding is far from complete, however, and as gaps in knowledge of the animal, of animal use of the forest, and of forest growth are filled and the information con- veyed to the public, scientific manage- ment of forest animals may become feasible. Wilderness as a Dynamic Ecosystem, with Reference to Isle Royale National Park The major problem of the status of man on earth can be approached in some degree through studies of other living things to assess the influences of density factors, behavioral homol- ogies, population dynamics, and other phenomena common to many species. Research in these plant-animal com- munities must produce a better under- standing of natural dynamics and life renewal in native types of forest, range, wetland, and aquatic habitats. 303 PART IX — TERRESTRIAL ECOSYSTEMS To these basic parameters must be added the complicating effects of hu- man culture on both man and hi? environment. Gross considerations suggest that the unguided technological culture in the hands of a rapidly increasing population is producing an unman- ageable complexity in human society and rapid deterioration in the envi- ronment and its component resources. If man is to endure on earth, the entire biosphere must be his ecosys- tem, preserved and kept productive through conservative use and under- standing management. Since man has never created an en- during, self-perpetuating ecosystem, he has much to learn from the study of natural processes. All conditions relative to human use and manage- ment are of interest and should be studied. However, the features of ecosystems that guarantee perpetua- tion are most clearly effective under primitive conditions. Thus, areas where primitive conditions are still operative are of special scientific in- terest. The least-modified communi- ties of living things are likely to be found on lands and waters set aside as "wilderness" or natural reserves of one kind or another. Isle Royale as a Prototype Ecosystem A roadless island of 210 square miles in northern Lake Superior ex- emplifies the kind of situation where fact-finding is possible under rela- tively undisturbed conditions. Isle Royale is a national park and may be visited by some 10,000 people during the tourist season from mid-June to early September. From the end of October to mid-May it is uninhabited except for a research group, using a small aircraft, that is present for seven weeks in February and March. Animal Populations and Associated Vegetation — Lying 15 miles from the nearest Canadian shore, the is- land is sufficiently isolated that it has not yet been colonized by certain mammals and birds found commonly on the mainland — especially deer, bear, raccoon, porcupine, and ruffed grouse. Lynx and marten disappeared from the island early in this century, as did coyotes in the mid-1950's. In the latter case, the advent of wolves about 1949 probably resulted in elimi- nation of the smaller competing canid. The fox does not appear to have been affected by such competition. The boreal forest and hardwood vegetation of Isle Royale was exten- sively burned over in the past cen- tury. Alteration of "natural" condi- tions by this human disturbance must be considered a matter of degree, since burning also took place in primitive times. The dynamics of forest successions is, in any event, significant. Early successional stages produce food and cover for such crea- tures as snowshoe hare and beaver, as well as browse for the moose. Thus, burning incident to drought cycles renews the habitat of many herbivores and indirectly supports their dependent carnivores. The mammal populations of Isle Royale have shown the instability that characterizes simplified animal communities. The moose illustrates this, since it reached the island in the first decade of the century, before its primary enemy, the wolf, was pres- ent. As a result, by the mid-1920's, moose had overpopulated and de- stroyed most of the available browse. In ensuing years, as a result of mal- nutrition and disease, moose died down to a low level. A fire in 1936 destroyed forest cover and initiated new brush-stage successions on about a third of the island. Moose were building up again when wolves crossed the ice and became estab- lished in the late 1940's. The Meaning of a Dynamic Wil- derness — In areas like Isle Royale, the U.S. National Park Service and other land-management agencies have been enabled to get a new view and concept of "wilderness" as a dynamic condition. Thus, a full spectrum of successional stages and habitat condi- tions enables a vegetation zone to support a wide variety of animal life. On any given site, animal life must change with maturation of the forest or other vegetation. In terms of land management, this means that agen- cies charged with the administration of natural areas must regard fire as a part of the primitive scene that should not be totally eliminated, even if this were possible. A strictly ap- plied policy of fire suppression would lead to the development of extensive monotypes representing the "climax," or stability phase, of plant life in a region. This would correspondingly reduce variety in both flora and fauna. Predator-Prey Relationships — Biological studies carried out by Pur- due University on Isle Royale over the past twelve years have been sig- nificant in revealing predator-prey relationships. The moose is the larg- est member of the deer family and the gray, or timber, wolf is its only effective natural enemy. In natural communities, large browsing and grazing animals depend in major de- gree on their predators for population control, the alternative being range damage and violent fluctuations in number. When it became known in the early 1950's that wolves had reached Isle Royale, it was evident that this was a situation in which nat- ural relationships of the two species could be studied. The major findings of the ensuing research program elucidate a mutu- ally beneficial relationship between predator and prey, an adjustment of relative stability that, by controlling the moose population, protects the habitat from over-use. As of mid- winter, an average population of 22 to 24 wolves is being supported by a moose population of about 900. The beaver is a secondary prey species furnishing 10 to 15 percent of the wolf's food. Numbers of the moose and beaver are limited by the wolf. As 304 1 ANIMALS in other large carnivores, wolf num- bers are self-limited largely through behavioral intolerances. Ordinarily there is one pack, most commonly around 15 animals, in which breeding takes place, and only one female will bear young. There has obviously been a high mortality among young wolves. The remains of more than 400 dead moose — nearly all wolf kills — have been examined on Isle Royale and their ages determined by tooth char- acteristics. On this basis, a composite life table and survivorship curve for the moose herd has been constructed. (See Figure IX-12) This illustrates a relatively high mortality of calves in the first year of life. In the next five years of its life, a moose evi- dently is at the peak of health and vigor, for it is seldom taken by wolves. From age 6 to the maximum age of 17 + , the moose is increasingly liable to be killed; the average adult taken is 9 to 10 years old. Correlated with advancing age and a higher mortality rate is an increasing in- cidence of physical disorders. The high selectivity for old and debilitated moose has been evident in the hunting habits of wolves. An Figure IX-12 — LIFE EXPECTANCY AND SURVIVORSHIP OF ISLE ROYALE MOOSE EXPECTATION OF LIFE IN YEARS 10 PERCENT MORTALITY 100 12 3 4 5 6 7 B 9 10 11 12 AGE IN YEARS 13 14 15 16 average of 12 moose have been ap- proached and brought to bay for every one killed. Vulnerable moose appear to be detected readily, while animals capable of strong defense are quickly passed by. In effect, the wolf culls the moose population and preserves a stock that can utilize the plant food supply most efficiently in producing new generations to sup- port wolves. Implications of the Isle Royale Findings This information reveals working mechanisms that confer durability on the ecosystem. It may be pointed out that population stabilization and turn- over rate in the wolf could only be studied where this species is protected from unnatural mortality. The natu- ral age structure of the moose herd and the selection effect of the preda- tor could be ascertained only where moose are protected from hunting and exposed to natural predation. Isle Royale National Park is perhaps the only area in the world where these conditions are met at present. The relationship of predator to prey has other, more direct, implica- tions, since big game herds are most commonly managed in the absence of effective natural enemies. The chief dependence in population limi- tation is on the gun and such factors as highway kill. Such artificial selec- tion will in time alter the direction of speciation and change the nature of such wild species as the deer. In the preservation of wild fauna and flora, for whatever benefits are to be realized, there are evident advantages in understanding the character and dynamics of the original associations in which living things developed. 305 PART IX — TERRESTRIAL ECOSYSTEMS 4. FOREST FIRE Research into Fire Ecology Fire is a useful tool in maintaining or modifying many vegetation types. Like all tools, however, it should be used in certain situations and not in others. For example, it should be used only where it can be controlled or where, if it escapes, the potential damage will be minimal or at least considerably less than the benefits. Some vegetation types can be im- proved by burning, others cannot. Still others, such as certain desert areas, support too little vegetation to carry a fire. Fire and climate are interrelated to the extent that a specific kind of cli- mate largely determines the kind of vegetation an area can produce. This, in turn, determines the fire-vegetation interrelationships — i.e., the readiness with which an area will burn, the effects of fire on modifying the plant cover, and the effects of this modifi- cation on the subsequent potential fire history of the area. Fire can have various interrelated beneficial effects on forests and grass- land as well as on many woodland (low-stature trees) and brushy areas. It may control undesirable woody species, thus promoting the growth of grasses and other herbaceous plants and, as a consequence, in- creasing the grazing potential. This modification often reduces soil ero- sion and runoff, since grasses provide a better close ground cover than many woody species. (See Figure IX-13) Other beneficial effects in- clude ease and economy of controlling accidental wildfires; soil fertilization from the ashes; control of ticks, poisonous snakes, and other undesir- able animals; control of fungi in the longleaf pine; creation of a better habitat for game animals, including turkeys, quail, and deer; reduction of excessive pine reproduction; main- tenance of profitable timber stands. Evaluation of Current Scientific Knowledge There is a rather large body of information on forest fire, much of it from foreign countries. In the United States, research is being carried on by the Forest Service at the Univer- sity of Washington, Seattle, and by the U.S. Forest Fire Laboratory in Mis- soula, Montana, among other places. Significant recent additions to scien- tific knowledge include the following: 1. Considerable theoretical work by Anderson and Beaufiat at the Forest Service's Intermoun- tain Research Station at Mis- soula. 2. Research on the practical as- pects of fire behavior by Coun- tryman, working out of the Forest Service Laboratory in Riverside, Calif. 3. Research on quantitative char- acteristics of fire in the desert grasslands by Claveran and Moreno at the University of Arizona, Tucson. 4. Research on fire temperature, development of mathematical formulations, and effect on mesquite and grasses being carried on out of Texas Tech University, Lubbock. 5. An analysis of fire ecology by Daubenmire. 6. An analysis by Batchelder of quantitative external factors such as air temperature, hu- midity, and wind in relation to fire behavior. 7. An analysis of fire in relation to the various vegetation types in the United States by Hum- phrey. 8. An aggressive and expanding program of research and dis- semination of information on Figure IX-13 — EFFECT OF FIRE ON MESQUITE SHRUBS The illustration to the left shows how mesquite chokes out grass under normal conditions. After a fire, the grass recovers rapidly while the mesquite recovers much more slowly. Controlled burning will eliminate the mesquite entirely and maintain the grassland. 306 FOREST FIRE fire ecology that has been car- ried on for several years under Komarek by the Tall Timber Research Station, Tallahassee, Florida. Despite the extent of the present data base, however, the entire sub- ject of fire ecology has been inade- quately studied. Three aspects that are particularly deficient are the re- actions of individual species to fire, the effect of repeat burns on species and vegetation types, and mathemati- cal modes of fire-ecosystem com- ponent relationships. Although a few data are beginning to accumulate that are serviceable as a base for both theoretical formulation and mathe- matical modeling, relatively little of the earlier research was suited to this approach. Currently, there ap- pears to be a trend in the direction of quantitative research and a continued increase is anticipated. Much more is needed. Status of Instrumentation — With a shift from qualitative to quantita- tive research, one progresses from minimal use of instruments to a need for instrumentation that is often expensive and highly sophisticated. Fire research today is moving in this direction, and, as a consequence, pro- posed investigations are requiring a budget for equipment that would have been unthought of only a few years ago. Remote-sensing and moni- toring equipment to obtain a variety of temperature and moisture meas- urements with time are particularly useful in these studies. Although much of the basic equipment is cur- rently available, refined techniques or specific situations will necessarily result in some modification or re- finement. Interaction with Other Environ- mental Systems — Despite the fact that most fire research has been of an applied nature — relating fire to noxious-plant control, forage produc- tion, timber yield, soil and water losses, and water yield — surprisingly little is known about the specifics of fire as it relates to other environ- mental systems. For example, many of our forests and grasslands can be improved for recreation and hunting by the judicious use of fire. These same areas can be rendered less li- able to destruction by wildfires when administered under a sensible pro- gram of controlled burning. Yet this relationship is almost completely un- explored. As the use of our wild lands in- creases consequential to the greater availability of leisure time and the need to escape from urban conges- tion, these lands are exposed to an ever increasing hazard of destruction from man-caused fires. The possibil- ity of reducing this hazard through a management-by-fire approach needs to be thoroughly investigated. In cities, we stress cleaning up poten- tial fuel in our fire-prevention cam- paigns; in forests, by contrast, we encourage accumulation of fuel to a point where an accidental fire can become a holocaust. Because of anti-fire propaganda and the inadequacy of research, there is considerable difference of opinion even in scientific circles on the bene- ficial and harmful effects of fire in most vegetation types. This contro- versy extends from the interpretation of historical records, through the long-time effects of previous fires and present fire-control policies on the "climax" vegetation, to the yield of such renewable natural resources as forage, game animals, timber, and water. Obviously, these differences of opinion must be resolvec lands are to be used most effective! and, in many instances, if we are to prevent their further deterioration or destruction. Requirements for Scientific Activity The principal needed scientific ad- vances are: (a) amplification of both qualitative and quantitative studies directed to specific vegetation types and individual species; (b) greater emphasis on man and his effect on the wildland environment as this af- fects the incidence of fires; (c) re- search on controlled burning as a means of pretreatment to control wildfires; (d) additional research on the generalities and specifics of fire (controlled and wild) as interrelated with all other aspects of specific ecosystems; and (e) extensive devel- opment of theoretical formulation, in- cluding mathematical modeling. The current scientific poverty of knowl- edge on this topic and the rapidly increasing rate of use of our wild- lands by man indicate a high degree of urgency for such research. Necessary significant advances could be made in a minimum of three years. Five years would be adequate to effect a more far-reaching breakthrough. In addition, many ecological studies require a long pe- riod of time to evaluate cause-effect relationships properly, and fire stud- ies are no exception. Aside from recovery time following a single fire, fire research often requires repeat burning at periodic intervals over a period of years. Studies of this sort should have a minimum duration of 25 years or more. 307 PART I\ — TERRESTRIAL ECOS\ STEMS The Role of Fire in Forest Management and Ecology Wildfires destroy vegetation and wildlife, may result in erosion and soil damage, leave unsightly vistas, are costly to suppress, and upset management plans and schedules. Thus, one of the most important tasks of the forest manager is to control wildfire, preferably by pre- vention. Only if the forest is free of wildfires, can management measures be applied as needed to yield the maximum amount of goods and serv- ices the forest is capable of pro- ducing. Prescribed fire, however, can be a useful tool for achieving these ends. It is often one of the measures that may be appropriate' in manipulating forest vegetation. But to use fire properly it must be fully controlled. Because of the great variation in climate, topography, soils, and vege- tation in the United States, a compre- hensive discussion of the role of fire in forest management and ecology would require much more space than is available here. This discussion will therefore be limited to the lob- lolly-shortleaf pine-hardwood forest type, which extends from Maryland to Texas through the middle South. It is the most important forest type in the southern timber economy and one in which the fire history encom- passes both substantially wild and prescribed fire. Ecology of Fire Fire was apparently the major fac- tor in maintaining extensive stands of pine long before the South was settled by man; it can probably be considered a natural ecological factor in southern pines. With the advent of human settlement and, later, ex- tensive logging, it became a frequent, almost annual occurrence over much of the region. Not until the organiza- tion of public forestry agencies and the establishment of permanent forest industries was the custom of indis- criminate annual woods burning brought under control. However, wildfire continues to be a frequent occurrence. Loblolly pine is the most prominent tree species in this type of forest. It usually occurs in relatively pure stands, being a serai species. On drier sites, shortleaf pine is often mixed with it, particularly in the western part of its range in Arkansas, Louisiana, and Texas. Pine is fol- lowed by deciduous hardwoods in the plant succession, and the pine stands characteristically have an un- derstory of hardwood tree and shrub species which eventually displace the pine unless a disturbance occurs that again favors pine. The effect of fire in loblolly pine stands is closely related to the bi- ological requirements and character- istics of the species and to the trend toward hardwoods in the plant suc- cession. The effect of fire on the succession depends on the age of the pine stand and on the intensity, fre- quency, and season of fire occurrence. Effect of Fire Intensity — Crown fires at any season of the year com- pletely destroy the pine stand. Fires of this type occur during periods of exceptionally high fire hazard, so that understory vegetation is also killed back to the ground. A burned soil surface is an excellent seedbed for loblolly pine, and the proportion of pine in the new stand depends on the supply of pine seed in the first year or two after the crown fire. Pine becomes established readily in the burned area, and the resulting stand is made up of pine seedlings and hardwood seedlings and sprouts. In one study, pine reproduction equalled hardwoods in basal area but not in number of stems nine years after a crown fire, showing that the pine stems were growing much faster than the hardwoods and would probably form the bulk of the dominant stand. Loblolly pine stands become fairly resistant to surface fires at about 10 years of age. Fire usually destroys younger stands completely but sur- face fires damage older stands very little. Furthermore during the dor- mant season such fires in older pine stands have very little effect on suc- cession. Litter is consumed and small stems are killed. The hardwood stems are quickly replaced by sprouting and the thin litter permits establishment of pine seedlings, so that conditions quickly become as they were before, except that hardwood stems are prob- ably more numerous. Effect of Season — In the loblolly pine range, wildfires are most likely to occur in spring, before growth begins, and in autumn, after leaf- fall. Winter fires are less frequent, while summer fires occur only during prolonged and severe dry periods. Fires during dry periods in the growing season may be very destruc- tive because initial vegetation tem- peratures are higher, growing tissues are more exposed to heat, and sprout- ing is less vigorous than that follow- ing dormant-season fires. Depending on how much of the overstory is killed, conditions after summer fire range from something resembling those after a crown fire to a reduction in the smaller understory hardwoods only. The succession varies accord- ingly. Fires within the first year after har- vest cutting differ in their effects, de- pending on the time of the year they occur in relation to pine seedfall. During the dormant season they de- stroy not only advance reproduction but also whatever seed is present. Hardwoods are highly favored be- cause a whole growing season must 30S FOREST FIRE pass before another crop of pine seed is produced. Meanwhile, hardwood sprouts and herbaceous vegetation produce a new mantle of litter that retards pine-seed germination. On the other hand, fires before seedfall may favor pine establishment if they do not occur too early in the growing season. Hardwood stems killed after early August sprout very little until the following spring. Con- sequently, fires in late summer before seedfall not only increase favorable seedbed conditions by consuming slash and undisturbed litter, but also give pine seedlings an even start with hardwood sprouts and seedlings the following spring. The earlier that fires occur in the summer, the more nearly the sprout and seedbed con- ditions approach those following dormant-season fires after harvest cutting. Effect of Frequency — While occa- sional fires favor loblolly pine re- generation, fires at intervals of less than 10 years eventually eliminate loblolly pine. Frequent fires repeat- edly destroy the pine reproduction, while hardwood stems are multiplied by seedling establishment, sprouting, and suckering. The process becomes relatively rapid when the dominant pine stand is clear-cut or otherwise destroyed. Continued frequent burn- ing may ultimately result in a vegeta- tional type dominated by grasses. Effects of Fire on Soil Fire heats the soil only very shal- lowly, but it affects the surface soil both physically and chemically. Physical effects range from none or negligible to measurable. The texture of the surface soil may be a factor. Thus, in the coastal plain of South Carolina, a fire-effects study showed no reduction in bulk density, total porosity, or percolation rate down to a depth of four inches, even after ten annual fires. Yet, in other coastal-plain locations, investi- gators have remarked on the com- pactness and reduced permeability of the soil surface after burning. It is logical to expect a greater effect on soils of heavier texture. A difference in effect on plant growth attributable to soil texture and drain- age characteristics was found in a study in northeastern North Carolina, where the area occupied by hardwood sprouts increased rapidly for three years after logging and site prepara- tion and then grew more slowly. On soils with poor surface drainage and plastic subsoils, hardwood reached 85 percent ground coverage in five years without burning but occupied only 65 percent in burned areas. On soils with good surface drainage, burning had the opposite effect: hard- wood cover increased faster on burned than on unburned areas, reaching about 10 percent greater coverage after five years. Erosion following fire is not a con- cern in the flat coastal plain but may be a danger farther inland on more pronounced topography. However, instances of serious erosion following fire in the loblolly pine range have not been reported. It may be that the vegetation grows back fast enough to protect the soil surface when the high-intensity summer storms occur. Fertility — Burning usually results in an increase in organic matter in- corporated in the surface soil. Fire- charred material filters into the upper layer. In addition, the ; mount of herbaceous vegetation that usually follows burning, especially grasses with their abundant fine roots, may be a source of increased organic mat- ter. These observations are from coastal plain locations. On sloping land, water would tend to carry ash and charred material from the site and organic matter increases might not be so pronounced; organic matter might even be reduced on heavier textured soils. Soil chemical properties are usually improved for plant growth after fire. Calcium is increased appreciably, with an accompanying decrease in acidity. Other mineral elements may be increased slightly through release from the litter. (See Figure IX-14) Nitrogen is increased, apparently from several sources. Burning re- leases much of the nitrogen in the litter but some remains in fire-charred material, which is concentrated close to the soil surface. The increase in herbaceous plants includes not only grasses but also legumes, possibly providing a source of nitrogen. How- ever, an observed annual increase of 23 kilograms per hectare in annually burned loblolly pine stands in the lower coastal plains of South Carolina could not be accounted for by the transfer of nitrogen from the litter to the mineral soil. Soil organisms in the litter and humus layers are destroyed by burn- ing, but the effects have not yet been comprehensively investigated. Ap- Figure IX-14 — QUANTITIES OF NUTRIENTS RELEASED BY BURNING TROPICAL VEGETATION Tropical rain forest (forty years old) Savanna woodland PHOSPHATE POTASSIUM CALCIUM MAGNESIUM 112 731 2,254 309 7 41 31 23 The table gives an estimate, in terms of pounds per acre, of several nutrients that are released to the soil by burning vegetation in two different tropical regions. 309 PART IX — TERRESTRIAL ECOSYSTEMS parently, the population of soil or- ganisms recovers rapidly after burn- ing and is associated with the increase in nitrogen. In the top four centi- meters of mineral soil in the South Carolina study, over four grams of nitrogen per hectare per day were fixed in the burned plots while only 0.2 grams were fixed in the unburned plots. However, the individual sam- ples from the burned plots ranged from no nitrogen fixation up to 61 grams per hectare per day, for rea- sons that were not evident. Disease — A survey throughout the South showed less Fomes annosus root rot on burned areas. This dis- ease spreads by growth of mycelia in the forest floor, or aerially by spores from the fruiting bodies. Con- sequently, fire may tend to retard the spread of the disease. Use of Prescribed Burning in the Timber Industry Prescribed fire has been recom- mended and widely used in the lob- lolly pine range for control of under- story hardwoods, site preparation for seeding or planting, and for fire- hazard reduction. Prescriptions for safe burning have been reasonably well developed by research and experience. Favorable conditions are: relative humidity of 40 to 60 percent; a wind steady in direction but under ten miles per hour at four feet above ground; and litter moisture content of 5 to 20 percent. Burning is safest when these conditions are first reached after a rain of half an inch or more. Backfires are preferred for areas with heavy fuel because they burn more slowly and less intensely. Headfires are used where fuel is light. Igniting the entire perimeter of the area is poor practice, since "hot spots" occur where fires from different directions meet, resulting in crown scorching and sometimes killing trees. For Understory Control — Because the hardwood understory is a major obstacle to re-establishment of the pine stand after harvest, its control has received a great deal of attention. If hardwoods are allowed to grow unchecked throughout a pine rota- tion, site preparation for regenera- tion is difficult and costly; often requiring use of heavy machinery. Periodic burning during the rotation holds this understory in check, with the burning interval determined by the growth rate of the understory sprouts. A prescribed fire will burn hardwood stems up to about two inches in diameter back to the ground. Thus, the burning interval may range from a few years up to ten years, depending on site quality, overstory density, and the species in the understory. Periodic burning for understory control is usually done in the winter. Summer burns are more difficult to control with several years' fuel ac- cumulation, and winter burning usu- ally fits better into the over-all schedule of seasonally determined forestry operations. Winter fires do not kill the rootstocks, so the popu- lation of understory plants is not reduced; in fact, the number of sprouts is usually greater during the first few years after the fire than before. In contrast to winter fires, summer fires reduce the understory popula- tion. When the parent stem is killed or cut in the summer, especially near the end of the spring flush of growth, the sprouts are much weaker than those arising from winter-killed stems. Plants that are not vigorous often die. Thus, two or three suc- cessive annual summer fires virtually eradicate the understory. This effect can sometimes be used to prepare loblolly pine stands for regeneration. The first burn is made in winter to lower the fuel level to the ground and make subsequent summer burns safe. Then, two or three summer burns reduce the understory popula- tion and leave a favorable seedbed. With an adequate supply of seed, a new stand is virtually assured. Prescribed burning for understory control apparently has no detrimental effect on the growth of the overstory pine stand. In South Carolina, even ten successive annual summer fires did not cause any reduction in growth of the overstory. With heavier sur- face soil, or on slopes where more water would be lost through in- creased runoff following burning, growth of the overstory might be reduced. For Site Preparation — Fire is also often used after harvest cutting for site preparation. Logging breaks up the litter and exposes mineral soil on an appreciable portion of the harvested areas, but much of the forest floor and the understory re- main undisturbed. Fires for seedbed preparation after logging are most effective in late summer, before pine seedfall, because pine seedlings have an even start with the competing hardwood sprouts the following spring. Other benefits are realized from periodic burning. The stand is es- sentially "fire-proofed." Because of greater ease of movement, the costs of timber inventory, tree marking, logging, and timber-sale supervision are reduced. Perhaps more important, the habitat for wildlife, particularly deer, is improved. Without fire, the browse plants grow beyond reach of deer early in the life of the stand. With periodic burning, especially in winter, the browse supply is repeat- edly replenished as the understory is killed back to the ground and promptly resprouts. Use Outside the South — Pre- scribed burning has been most widely practiced in the South but is now coming into use in other sections of the country. In the Lake States, it is used as a site-preparation measure for jack- and red-pine regeneration and for understory control in red pine. The effects on vegetation seem 310 FOREST FIRE to be much the same as they are in the South. Sprouting of hardwood species is greatly reduced by summer fires, and several summer fires will virtually eliminate hazel, the most serious and widespread competitor of pine regeneration in Minnesota. Spring and fall burns are less effec- tive and sometimes more erratic in behavior. Use of fire for seedbed preparation in black spruce has been developed through research and is now being used on a limited scale. Mature black spruce is cut in strips. The strips are burned while the water table is high. The slash and certain mosses, which are a poor seedbed for spruce, are eliminated and a favor- able seedbed of burned peat is created on most of the area. Clearcut blocks are also seeded artificially following prescribed burning. In the West, fire is used mainly in Douglas fir and pine types for slash disposal after harvest cutting, which also prepares the area for seeding or planting. Needs and Limitations of Prescribed Fire While fire is a very useful tool, it requires great care to apply prop- erly. Its effects are not known com- pletely, even in the South, and it has sharp limitations. It is applicable for understory control only where the overstory is resistant to fire, which restricts its use for this purpose to the hard pine types. It has some- what wider applicability for site preparation. Use of fire in the management of forests has been applied with vary- ing results, some promising, some disappointing. One of the main prob- lems is in understanding the total effects of burning in order to achieve consistent results either for forest reproduction or wildlife management. To prescribe fire for specified re- sults while avoiding damages to the stand and site, much more informa- tion is needed on the relation of fire intensity to weather factors and fuel conditions, and the effect of various fire intensities on the vegetation and soils. While research may show that particular weather and fuel condi- tions will produce a certain fire in- tensity, such narrowly specified con- ditions will occur only infrequently and for limited periods. Thus, the duration of the required weather and fuel conditions determines the acre- age that can be burned, which may often be less than planned. In addi- tion, fire intensity will vary with vegetational and fuel types over the burn areas, with corresponding varia- tions in results. Because of these limitations and variations, fire can only be an imprecise tool at best. Consequently, if fire is to be used, information to prescribe it correctly is essential. Limitations of the Southern Expe- rience — It is not safe to assume the effects of fire on soils observed in the South are applicable elsewhere, for two reasons. The frequent past burning in the South may be a factor in the observed soil effects — any pine area used to study fire effects is likely to have been burned many times in the past. And soils elsewhere are not comparable to those in the southern pinery. Even in the South, however, the available information comes from only a few studies in limited localities. Consequently, the effects of fire on erosion, soil struc- ture, chemical characteristics, and soil biology should be investigated along with studies of vegetational effects and development of techniques wherever fire is to be used. Burning undoubtedly releases mineral nutri- ents contained in the forest litter, but these might be largely lost on slopes and deep sands. Very little is known about fire effects on soil flora and fauna beyond their immediate de- struction in the burned portion of the forest floor, yet they may be very important in longer-term soil produc- tivity and the health of the forest vegetation. It should be recogni . ver, that burning for site prep; done only once in the life ol stand. In southern pines, a rotation (time from establishment to harvest of a timber stand) may be as short as 20 or 25 years. In the North and West, a rotation is much longer. Burning for hardwood control during the rotation is done more frequently and the effects on soils may be more important. Effect of Smoke — An aspect of prescribed burning that has only re- cently been recognized is that smoke is an effect that needs to be con- sidered. Weather and fuel conditions satisfying prescriptions for burning may occur simultaneously over ex- tensive areas and many fires may be burning at the same time. Locally, low-lying palls of smoke can reduce visibility enough to make automobile driving hazardous. People in the vicinity may suffer physical discom- fort. On a larger scale, one could speculate that weather might con- ceivably be affected by fire under cer- tain atmospheric conditions. Smoke particles might serve as condensation nuclei, resulting in cloudiness, or the smoke itself might accumulate at tem- perature-inversion levels, obstructing back radiation and changing tem- peratures at ground level. Thus, the effects of the smoke alone might pre- clude prescribed burning in some localities. Needed Scientific Activity Several aspects of fire ecology should receive serious attention: 1. Effects of fire or burning are long-range. Published reports are often based on short-term studies, both in management and ecology. Long-term studies with both ecological and man- agement emphasis are needed. 2. There should be more integra- tion of ecological and manage- ment research. The two are of- 311 TART IX — TERRESTRIAL ECOSYSTEMS ten separate schools of thought, and their approaches, methods, and results should be more closely integrated so that man- agement workers would benefit and apply ecological informa- tion and ecologists would be made more aware of the pos- sible applications, economics, and practical potentials in- volved. 3. Fire affects all aspects of the biotic environment, and these, too, must be investigated, in- cluding: soil moisture, tem- perature, texture, chemistry, soil microorganisms and fauna, seedbed conditions, recovering vegetation including mosses, herbs, shrubs, and trees, af- fected animal populations, and air and water pollution. Inter- relationships among these are important in understanding the total effect of fire. 4. Application of findings from one forest and soil type to an- other are usually not practical, and few generalizations can be made. The total picture for each type of situation must be worked out separately. There is need for a careful review and analysis of work done in both ecology and man- agement areas to integrate find- ings to date and avoid dupli- cation of efforts, a fault of present and past work. 312 5. POLAR ECOSYSTEMS Polar Flora and Vegetation The polar tundra with a perma- frost base, as found in the high arctic and antarctic, is one of the most fragile types of world vegeta- tion. As with any ecosystem, the living components in the tundra — the microorganisms, plants, and an- imals — are in delicate balance with their environment; any change in the environment will result in some changes in the composition and rela- tionships of the living components. Since the number of different types of living organisms in the polar tundra are much fewer than in other ecosystems, even small changes often cause drastic changes in the composi- tion and relationships of the living organisms. For example, depression by heavy vehicles, overgrazing, or trampling by animal herds or humans at certain times of the year can result in complete local destruction of the tundra vegetation. (See Figure IX-15) Recovery to the original vegetation, if it occurs at all, takes at least 100 years. In the arctic, economic develop- ment has already begun and is likely to increase significantly in the future. It is very important that the effects of these developments on the fragile tundra be studied by trained scien- tists so that an assessment may be made as changes take place. In the antarctic, the only threat to the tun- dra is from base construction and tourism; these threats have thus far been moderated by the provisions and recommendations of the Antarc- tic Treaty relating to conservation of antarctic fauna and flora. Because it appears to be much sim- pler than the biological systems of the temperate and tropical regions, the polar tundra offers unique oppor- tunities for studying problems in- volving the interrelations between the environment and the living or- ganisms. This simplicity in appear- ance results from the lack of large trees, which in other regions make for a distinct multi-level system (the ground, the herb layer, the shrub layer, and several tree-top layers) with many different types of dwelling places for other organisms. In the polar regions, the levels are few, and thus there are fewer complica- tions involved in studying any one of them. Despite this relative sim- plicity, however, it does not neces- sarily follow that the processes or interrelations within the tundra are any easier to understand than those in a temperate or tropical forest. Recent Developments in Polar Studies In the antarctic, except for areas of the northern Antarctic Peninsula, the tundra is the most depauperate type, composed entirely of nonflower- ing plants, mostly lichens, mosses, and algae. Even where this tundra is present, it is very spotty, dependent primarily on the availability of water in a land where desert conditions prevail and where most of what water there is is unavailable to plants because it is frozen into snow and ice. The more humid northern Antarc- tic Peninsula and the sub-antarctic Figure IX-15 — A SECTION OF THE TUNDRA BIOME The photograph shows a section of tundra or marshy plain near Point Barrow, Alaska. The land is characterized by a lack of trees and an upper surface that is spongy and uneven due to the freezing and thawing of the poorly drained land. The picture shows polygons that are 15 to 25 feet across, a result of winter freezing. Beneath the surface, at depths ranging from a few inches to several feet, is the permafrost, or permanently frozen soil, that is the ultimate limit to plant root growth. 313 PART IX — TERRESTRIAL ECOSYSTEMS islands have a tundra more nearly resembling that of the arctic, but containing fewer types of flowering plants. There are only two species of flowering plants native to the Ant- arctic Peninsula. The antarctic tundra has been less studied than that of the arctic. How- ever, as a result of the Antarctic Treaty and the international scientific cooperation of the past ten years, great strides have been made in gath- ering details about the plants and their environments. Major works have been written or are in the process of being written about flowering plants in all parts of the arctic (Siberia, Scandinavia, and central Canada). Work on the non- flowering plants is less extensive but is also progressing. A good begin- ning has been made in the under- standing of the plants that occur in the antarctic as well. Major flora of the various plant groups — lichens, mosses, and algae — will probably be reported on in the near future. The flora of the sub-antarctic islands are also being studied, and, again, reports on major flora are likely to appear relatively soon. Thus, it can be said that much of the basic investigation about polar- region plant life is done or soon will be. This cannot be said about the interrelations among the plants and animals and their environments. Tliis is the needed area for study. Needed Scientific Activity Although, as noted, we know a fair amount about the distribution of the plants and animals in the tundra, we lack detailed information about all of the interrelationships. Ecosystem modeling, a way of math- ematically taking into account the various factors of the environment and their interrelationships with the living organisms, requires such de- tailed information for each com- ponent of the model. Once a meaningful model has been made, predictions can be soundly based. (See Figure IX-16) The Tundra Biome study group of the International Biological Program has proposed that such things as productivity of the plants and of the whole tundra be investigated. Multi- disciplinary studies of the sort that have been done at Cape Thompson and Kodiak Island in Alaska would be valuable in providing a better understanding of the tundra ecosys- tem. There is need to study the ecological interrelationships and the specific changes that are being brought about bv planned environ- mental change. Only then will it be possible to predict meaningful changes that are likely to occur when other environmental changes are made. 314 ECOSYSTEMS Figure IX-16 — FLOW DIAGRAM OF A WET COASTAL TUNDRA ECOSYSTEM Numerals replacing flow lines 1— To carcasses 2 — To feces 3— To plant litter A — To saprovores 5 — To soil organic matter 6 — To available soil nutrients Snow Process names C— Consumption D — Leaching and decay M— Migration and dispersal P— Photosynthesis S— Solar heat T— Translocation U— Uptake •—To aquatic system Soil unfrozen moisture Depth of thaw Nonvascular above ground Nonvascular below ground M - 1,2 ■ Dicots above ground Dicots below ground TTT 1,2 > Available soil nutrients. Longspurs Saprovores Monocots above ground Monocots below ground i i Frozen edible Standing dead LF Soil organic matter M 1,2 Carnivorous arthropods 7 Plant litter Soil micro- organisms II This is a rather detailed flow chart of a tundra ecosystem representative of the Point Barrow area. The driving variables (shaded areas) are solar heating, moisture availability, nutrient availability, and photosynthesis. The net result is seen as the production and maintenance of such animal populations as weasels, shorebirds, etc. Although the diagram is basically an energy-related chart, the rates of flow of energy between points are not indicated. 315 PART X ENVIRONMENTAL CONTAMINANTS EFFECTS OF ENVIRONMENTAL POLLUTANTS AND EXPOSURES ON HUMAN HEALTH AND WELL BEING In addition to their often profound ecological implications, man's activities and their by-products have negative as well as positive effects on human health and well being. In some cases, these effects are long-term and only now are beginning to be understood; in other cases, effects are suspected but not yet proved; and in still others, effects as yet unsuspected may exist. The charts below outline the situation as it is at present; however, the current climate of environmental concern is apt to lead to research that will document and modify this outline rather than expand it. The following listings have been made available through the courtesy of the World Health Organization. COMMUNITY AIR POLLUTION (Note: Items in parentheses refer to effects other than those directly affecting human health status) Agents, pollutants Definite Effects Possible Effects Sulfur dioxide (effects of sulfur oxides may be due to sulfur, sulfur trioxide, sulfuric acid or sulfate salts) Sulfur oxides and particulate matter from combustion sources Particulate matter (not otherwise specified) 1. Aggravation of asthma and chronic bronchitis 2. Impairment of pulmonary function 3. Sensory irritation 4. (Effects on vegetation) 6. Short-term increase in mortality 7. Short-term increase in morbidity 8. Aggravation of bronchitis and cardiovascular disease 9. Contributory role in etiology of chronic bronchitis and emphysema 10. Contributory role to respiratory disease in children 12. Impairs visibility (soils surfaces and materials) 13. (Alteration in incident sunlight) 5. (In certain conditions, produces effects on buildings and works of art) 11. Contributory role in etiology of lung cancer 14. Increase in chronic respiratory disease 319 PARI \ - ENVIRONMENTA1 CONTAMINANTS COMMUNITY AIR POLLUTION (continued) Agents, pollutants Definite Effects Possible Effects Oxidants (including ozone) Ozone Carbon monoxide Nitrogen dioxide Lead Hydrogen sulfide Mercaptans Fluorides 15. Aggravates emphysema, asthma, and bronchitis 16. Impairs lung function in patients with bronchitis-emphysema 17. Eye and respiratory irritation and impairment in performance of student athletes 18. Increased probability of motor- vehicle accidents 20. Irritant to respiratory tract 21. Impairs lung function 23. Impairs oxygen transport function 27. (Discolors atmosphere) 30. Increased storage in body 31. (Lethal to animals eating contaminated feed) 34. Increased mortality from acute exposures 35. Causes sensory irritation 36. (Damages property (paint)) 39. Sensory irritation (odor) 41. (Damages vegetation; harms animals) 19. Alteration of oxygen consumption 22. Acceleration of aging, possibly due to lipid peroxidation and related processes 24. Increased general mortality and coronary mortality rates 25. Impairment of central nervous system function 26. Causal factor in atherosclerosis 28. Factor in pulmonary emphysema 29. Impairment of lung defenses such as mast cells and macrophages or altered lung function 32. Impairment of hemoglobin and porphyrin synthesis 33. Probably decreases enzyme level 37. Impaired sensory detection or reflexes 38. (Socio-cultural nuisance) 40. Headache, nausea, and sinus affections 42. Fluorosis of teeth 320 COMMUNITY AIR POLLUTION (continued) Agents, pollutants Definite Effects Possible Effects Ethylene Asbestos Chlorinated hydrocarbon pesticides Organo-phosphorus pesticides Other odorous compounds Hydrothermal pollutants Beryllium Air-borne microorganisms 43. (Damages vegetation and hastens ripening of fruit) 44. Produces pleural calcification* 45. Malignant mesothelioma, asbestosis* 47. Stored in body, mostly from milk and animal fats 48. (Ecological damage) 50. Acute fatality 51. Acute illness 52. Impair cholinesterase 54. Sensory irritation 56. (Can influence local climate and interfere with visibility) 58. Berylliosis with pulmonary impairment 59. Air-borne infections 46. Contributes to chronic pulmonary disease (asbestosis and lung cancer) 49. Impairment of learning and reproduction 53. Impairment of general health, and of adaptation 55. Headache and sinus affections 57. (Influence on action of hydroscopic pollutants) * These effects have been shown to occur in the vicinity of mining and processing operations. General community exposure may cause these effects, but this has not definitely been proven. 321 PART X — ENVIRONMENTAL CONTAMINANTS FOOD AND WATER CONTAMINANTS Agents, pollutants Definite Effects Possible Effects Bacteria Viruses Protozoa and metazoa Metals Nitrates and/or phosphates and/or organic matter "Softness" factor Sulfates and/or phosphates Dissolved solids Fluorides Chlorinated hydrocarbon pesticides Oil-petroleum Thermal (heat) pollution Phenols 1. Epidemic and endemic gastro-intestinal infections (typhoid, cholera, shigellosis, salmonellosis, leptospirosis, etc.) 2. (Malodor) 4. Epidemic hepatitis, and other viral infections 6. Amoebiasis, schistosomiasis, hydatidosis and other parasitic infections 7. (Malodor) 8. Lead poisoning 9. Mercury poisoning (through food chains) 10. Cadmium poisoning (through food chains) 11. Arsenic poisoning 12. Chromium poisoning 15. Methemoglobinemia (with bacterial interactions) 18. (Eutrophication) 19. (Malodor) 21. Gastro-intestinal hypermotility 22. Impaired potability 23. (Impaired value for irrigation and industry) 24. Fluorosis of teeth when in excess 25. (Ecological damage) 26. Impaired potability 27. (Ecological damage) 28. Impaired potability 3. Secondary interaction with malnutrition and with nitrates in water (cf., No. 15) 5. Eye and skin inflammation from swimming 13. Epidemic nephropathy 14. "Blackfoot" disease 15. Methemoglobinemia (bacterial interaction not required) 17. Nitorsamine effects on mutagenesis and/or carcinogenesis 20. Increase in cardiovascular disease 322 LAND POLLUTION Agents, pollutants Definite Effects Possible Effects Human excreta Sewage Garbage Industrial and radioactive waste Fertilizers Pesticides (food chain) 1. Schistosomiasis, taeniasis hookworm, and other infections 2. Urban filariasis 3. Flies and other vectors 4. Odor 5. Rat and other rodent infestation 6. Flies and other vector-transmitted diseases 7. Odor 8. Pollution of water and air from disposal practices 10. Storage and effects from toxic metals and other substances through food chains 11. (Loss of vegetation and soil, and altered ecology) 12. Ground water pollution effects, surface water pollution effects 13. Contamination of vegetation and secondary foodstuffs 9. Typhus, plague, leptospirosis, and other infectious diseases 323 PART X — ENVIRONMENTAL CONTAMINANTS THERMAL EXPOSURES Agents, pollutants Definite Effects Possible Effects Cold damp Cold dry Hot dry Hot damp 1. Excess mortality from respiratory disease and fatal exposure or frostbite 3. Excess morbidity from respiratory disease and morbidity from frostbite and exposure 5. Mortality from frostbite and exposure 7. Morbidity from frostbite and respiratory disease 8. Heat-stroke mortality 9. Excess mortality attributed to other causes 10. Morbidity from heat stroke and excess from other causes 11. Impaired function; aggravation of renal and circulatory diseases 12. Increase in skin affections 14. Heat-exhaustion mortality 15. Excess mortality from other causes 16. Heat-related morbidity 17. Impaired function 18. Aggravation of renal and circulatory disease 2. Contributes to excess mortality and morbidity from other causes 4. Rheumatism 6. Impaired lung function 13. Increase in prevalence of infectious agents and vectors 324 RADIATION AND MICROWAVES Agents, pollutants Definite Effects Possible Effects Natural sunlight Diagnostic X-ray Therapeutic radiation Industrial uses of radiation and mining of radioactive ores Nuclear power and reprocessing plants Microwaves 1. Fatalities from acute exposure 2. Morbidity due to "burn" 3. Skin cancer 4. Interaction with drugs in susceptible individuals 7. Skin cancer and other skin changes 10. Skin cancer 11. Increase in leukemia 12. Acute radiation illness 16. Acute accidental deaths 17. Radiation morbidity 18. Uranium nephritis 19. Lung cancer in cigarette-smoking miners" 20. (Effects on food chains) 22. (Ecological damage due to thermal pollution of water) 23. Storage of potentially harmful materials in the body 24. (Radioactive contamination of air, land, and water) 5. Conditional exacerbation in porphyria 6. Increase in malignant melanoma 8. Contributing factors to leukemia 9. Alteration in fecundity 13. Increase in other cancers 14. Acceleration of aging 15. Mutagenesis 21. Increase in adjacent community morbidity 25. Increase in cancer incidence 26. Community disaster 27. Alteration in human genetic material 28. Tissue damage ■ While this is an occupational exposure, its interpretation is of great importance for community health protection. 325 PART X — ENVIRONMENTAL CONTAMINANTS NOISE AND VIBRATIONS Source Definite Effects Possible Effects Traffic Aircraft (including sonic boom) Recreational Official (bells, sirens) Technological— building construction, paving, etc. Domestic noise Vibrations 1. Temporary loss of hearing 2. Impairment of rest and communication 3. Sensory irritation 8. Permanent hearing loss 9. Temporary hearing loss 10. Impairment of rest 11. Impairment of communication 12. (Damage to property) 14. Temporary hearing loss 15. Interference with rest 16. Interference with communication 17. Sensory irritation 19. Temporary loss of hearing 20. Sensory irritation 21. Temporary hearing loss 23. Impairment of rest and communication 25. Discomfort 4. Progressive hearing loss 5. Increased social disorganization 6. Contributory to cardiovascular disease 7. Impairment of circulatory function 13. Aggravation or cause of mental illness 18. Aggravation of tension-related conditions 22. Progressive hearing loss 24. Produces tension 26. Articular and muscular disease 27. Adverse effects on nervous system 326 HOUSING AND HOUSEHOLD AGENTS Agents, pollutants Definite Effects Possible Effects Heating and cooking Fumes and dust Crowding Structural factors (including electrical wiring, stoves, and thin walls) Paints and solvents Household equipment and supplies (including pesticides) Toys, beads, and painted objects Urban design Acoustical factors 1. Acute fatalities from carbon monoxide, fires and explosions, and discarded refrigerators 3. Acute illness from fumes 4. Impaired oxygen transport 5. Aggravation of asthma 8. Spread of acute and chronic disease 9. (Impairment of social interaction and of privacy) 10. Accidental fatality 11. Accidental injury 12. Morbidity and mortality from lack of protection from heat or cold 13. Morbidity and mortality due to fire or explosion 14. (Impairment of privacy) 16. Childhood lead-poisoning fatalities, associated mental impairment and anemia 17. Renal and heptic toxicity 18. Fatalities and morbidity from fire 20. Fatalities from fire and injury 21. Morbidity from fire and injury 22. Fatalities from poisoning 23. Morbidity from poisoning 24. Mortality and morbidity 25. Increased accident risks 26. (Social disruption and isolation) 28. Impairment of rest and sleep 2. Increase in diseases of the respiratory tract in infants 6. Increase in chronic respiratory disease 7. Increase in heart disease 15. Mental illness and behavioral disorders 19. Acute effects of other vapors and paints 27. Psychological effects from lack of diversity, accessibility, recreational areas 29. Possible aggravation of tension- related conditions 327 1. AIRBORNE CHEMICALS Chemical Contaminants in the Atmosphere Atmospheric contamination is dif- ficult to define precisely, since "pure air" itself is a mixture. Water con- tamination is a simple concept, since "pure water" is a single chemical sub- stance. Even with human influences absent, the air has a variable compo- sition in both time and space. There is evidence that there was more oxy- gen in the atmosphere at the peak of the carboniferous era than there is today; and the atmosphere close to an erupting volcano is bound to be different in composition from the air in the midst of a pine forest. Definition of Contamination To discuss the contamination of a mixture it is necessary to define an arbitrary composition as "pure." It is usual to define dry pure air as con- taining roughly 78 percent nitrogen, 21 percent oxygen, 0.03 percent car- bon dioxide, and the remaining 0.97 percent noble gases. (See Figure X-l) Water vapor is present in pure air in highly variable amounts. Under this definition, all air is con- taminated to some degree. Much of the contamination is both natural and beneficial. The development of clouds and precipitation, for example, re- quires the presence of "nucleation centers," usually consisting of dust, sea salt, and particles formed in the air by reactions between gaseous contaminants. Some contaminants are intrinsically harmful to things that humans value or harmful in excessive concentra- tions. If these contaminants are pro- duced directly or indirectly by human Figure X-1 — COMPOSITION OF CLEAN, DRY AIR Component Content %by volume ppm Nitrogen 78.09% 780,900 ppm Oxygen 20.94 209,400 Argon .93 9,300 Carbon dioxide .0318 318 Neon .0018 18 Helium .00052 5.2 Krypton .0001 1 Xenon .000008 0.08 Nitrous oxide .000025 0.25 Component Content %by volume ppm Hydrogen .00005% 0.5 ppm Methane .00015 1.5 Nitrogen dioxide .0000001 0.001 Ozone .000002 0.02 Sulfur dioxide .00000002 .0002 Carbon mon- oxide .00001 0.1 Ammonia .000001 .01 The table shows the major and some of the trace constituents of clean, dry air near sea level. The concentrations of some of the gases may differ with time and from place to place. Some of the data are open to question, but the values are meant to indicate the order of magnitude. activities, they are called air pollut- ants. In a few instances a pollutant is not, paradoxically, a contaminant. For example, excessive industrial steam meets the usual criteria of a pollutant if it obscures visibility on a major highway; yet strictly speak- ing it is no more than a part of the variable fraction of water vapor as- cribed to "pure" air. The distinction between a harmful contaminant and a pollutant may be a narrow one. Natural contamina- tions, such as a rain of volcanic ash or a desert sandstorm, are not classed as pollutants. But when human ac- tivity is responsible for their occur- ring — as it was in the great dust storms of the 1930's — these contami- nants are classed as pollutants. We can legitimately consider even a sand- storm in the Sahara as pollution, since the great desert, at least in its present extent, appears to have been caused by overgrazing. A final case needs to be distin- guished in the definition of contami- nation. Air may be rendered harmful to life, not by the presence of con- taminants, but by the absence of oxygen. Since combustion within the 48 contiguous United States now re- quires twice as much oxygen as all the green plants in the area produce, the hazard of depleted air may be- come acute. The Environmental Problem The sources of pollutants are gen- erally well characterized and the com- position of most is known. Much less is known about natural contaminants. Many come from enormous areas at miniscule concentrations. For exam- ple, air that blows into Barbados from the tropical Atlantic contains a 329 PART X — ENVIRONMENTAL CONTAMINANTS minute trace (about one part in two billion parts of air) of sulfur diox- ide. In spite of all the sulfur diox- ide put into the air by burning high- sulfur fuels, it is unlikely that any of this human contribution reaches Barbados. Instead, some natural, probably maritime, source must be responsible for maintaining the con- centration at this level. It is possible to compute how much carbon monoxide the industries and automobiles of the world release into the atmosphere, and it appears that the worldwide concentration of this gas is about one part in ten million. Knowing these facts, it should be possible to estimate how rapidly car- bon monoxide is removed from the air. However, it has recently been discovered that the ocean also con- stitutes a vast and diffuse source of the gas; thus a much higher removal rate must account for the known con- centration. At present the removal process is unknown, yet it must be discovered if environmental manage- ment is to be possible. A knowledge of the lifetime of carbon monoxide in air would be a valuable clue from which to begin. Over-all, one fact is clear. Many pollutants are also released naturally, though at lower concentrations. If there were no natural processes to remove them, the atmosphere would be far more heavily contaminated than it is, even in the absence of human contributions. Hence there must exist an enormous complex of processes which maintain the atmos- phere at substantially its present composition. Every component, even most of the minor ones here called contaminants, is present in the global atmosphere as a result of closely bal- ancing processes of generation and removal. These processes are such that a substantial increase or decrease in generation will be rapidly counter- acted, at least in part, by a corre- sponding change in rate of removal. However, this sort of feedback con- trol generally has its inherent limits. A very simple example is the ability of living vegetation to remove sulfur dioxide from the air. Studies in Panama show that a very small con- centration of this gas is a natural contaminant in the tropics, perhaps emanating from decayed vegetation. If this supposition is correct, then the small natural concentration of sulfur dioxide results from a balance of its release from dead plants and its con- sumption by living plants. The balanced system will accom- modate a considerable input of sulfur dioxide from pollutant sources, and, in fact, the gas has been shown to absorb rapidly into vegetation. If the added input is too great, however, plants perish, and the system fails. It is further obvious that all forms of life release wastes to the environ- ment. Wastes by definition are in some degree toxic to the organisms that excrete them; hence, man or any other organism reaching an intoler- able population density will pollute the environment with respect to his own survival. Man is far worse than his numbers indicate because he aug- ments his own energies by the syn- thetic release of energy, thus gener- ating additional wastes. The energy generated in the United States alone is equal to that of 100 billion humans. These "equivalent energy slaves" are a measure of our standard of living; they are also a true measure of our impact upon the environment. Clearly, no acceptable degree of control is imminent for the human population. If both world population and the U.S. living standard were frozen at present levels, and the rest of the world raised to the U.S. stand- ard, a tenfold increase in pollutant emissions would result, assuming con- stant technology. Yet population can- not be stabilized overnight, and the rest of the world does aspire to the U.S. living standard; although con- stant technology is a poor assump- tion, the developing countries have shown little inclination to avoid the environmental errors of our own past. These collective considerations de- lineate the environmental problem. The human impact has reached an alarming level, and much of its force is mediated by the atmosphere. (See Figure X— 2) Beyond the above quali- tative statement, what is the state of our knowledge? State of Scientific Knowledge Frankly, our over-all knowledge is extremely fragmentary. Pate, Lodge, and their co-workers at the Na- tional Center for Atmospheric Re- search have reported on atmospheric composition in the moist tropics in regions far from pollution sources. Keeling and several others continue to measure worldwide distributions of carbon dioxide. At the Stanford Research Institute, Robinson and Robbins have obtained apparently reliable figures for the worldwide concentration of carbon monoxide, and have shown the presence of an unsuspected natural source of this gas in the ocean. Patterson and his group at the California Institute of Technology, by analyzing ice cores from the Greenland Ice Cap and from Antarctica, have documented the worldwide secular increase in atmospheric lead. All of this infor- mation is necessary to assess the orig- inal state of the system that mankind is now disturbing. O'Keeffe and his colleagues in the Environmental Protection Agency, Axelrod, Lodge, and others at the National Center for Atmospheric Re- search, and numerous academic sci- entists are gradually developing ana- lytical methods of sufficient sensitiv- ity, specificity, and reliability to assess both the reputedly unpolluted and polluted environment. At the University of Washington, Charlson has developed a nephelometer that rapidly assesses local atmospheric haziness and also makes possible 330 EMICALS Figure X-2 — POLLUTION — AN ENVIRONMENTAL PROBLEM The picture illustrates the multiple problems of pollution encountered in a small city in western Pennsylvania. In the first instance, the gaseous effluents from the industrial complex form a cloud over and downwind of the city. This cloud, in addition to causing changes in the local radiation balance and possibly other local changes, is composed of water vapor mixed with pollutants such as sulfur dioxide that cause damage to plants, animals, and man. The city is located on a river into which industrial and municipal wastes are dumped; in earlier days there was no need to worry about the consequences of such action and now, although funds are becoming available to help build water-treatment plants, it is difficult to keep up with the need. The question of solid waste disposal presents yet another unsolved problem. The original city dump along the river only makes the water pollution worse. Incineration causes air pollution. Sanitary land fills use up large quantities of desirable land. Shipping the wastes by rail or barge may help the local problem but does not eliminate it. Furthermore, all these problems spill over into downwind or downstream localities. laboratory experiments on haziness modification. He has shown that in many typical atmospheres the tur- bidity measured by his instrument correlates closely with the mass of the particles present. The Environmental Protection Agency (EPA) maintains monitoring and surveillance activities in most of the major U.S. cities, and some local agencies are measuring their own pol- lution problems. However, most of the widely used techniques are five to twenty years old and are less effec- tive than most recently developed methods. Nearly all of them lack precision and specificity, and thus the results are affected significantly by the presence of pollutants not being measured. The Measurement Problem — Be- fore newer techniques are accepted, verifiable standards need to be estab- lished for precision, specificity, and accuracy in measuring pollutants at concentrations as low as one part in a billion parts of air and in the pres- ence of equal or larger amounts of all other possible pollutants. This meas- urement problem is not only unre- solved, but there has been no agency with the explicit and exclusive re- sponsibility for evaluating proposed analytical methods. Only recently has a group been created with the responsibility of evaluating existing methods of atmospheric analysis, and it is not yet certain to what extent this group will be successful. Mean- while, there is a strong tendency to use old techniques, which at least provide numbers, even thougl may be some uncertainty as to the physical meaning of those numbers. Neio Attitudes — The immediate past has seen remarkable changes, not so much in the state of knowledge as in the state of mind of the at- mospheric research community. Not many years ago, an announcement of plans to study atmospheric chemistry in the tropics invited accusations of junketing from one's colleagues. Only a short time past, many scientists felt that usefulness tainted research re- sults; today "relevant" research topics are eagerly sought by formerly "pure" scientists. New Methods — Older research tools have been improved and simpli- fied and new tools have been devised. Gas chromatography with more sensi- tive detectors, atomic absorption, neu- tron activation, chemiluminescence and fluorescence quenching — all these and others provide the means to ana- lyze even smaller, more dilute, and more complex samples. This combination of new methods and progressive attitudes in environ- mental study summarizes the current status of trace chemistry of the atmos- phere. While recent achievements are not great, there is now an expectancy and readiness for major scientific ad- vances in this field. Needed Scientific Activity This mood of expectancy has led no fewer than a half dozen groups around the world to examine the pos- sibility of routine monitoring of sev- eral major contaminants in the air. Carried out at sites remote from local pollution, such work could provide for the first time true "benchmark" measurements against which future changes in the atmosphere can be gauged. Recently, a number of groups within the United States independ- ently concluded that a saturation study is needed of pollution in a single city, ranging from the point 331 PART X — ENVIRONMENTAL CONTAMINANTS of individually emitted pollutants to the far downwind zone where pollu- tants merge with the general atmos- phere. Studies of (a) urban pollution, (b) analytical methods, and (c) laboratory models of reactions producing, alter- ing, and removing contaminants are three areas of atmospheric chemis- try that require immediate attention. These studies alone are not sufficient, however, to solve the environmental problem. Supporting work needed in the biological sciences is lagging for lack of precise methods to assess the ecological impact of contaminants; there must be innovation in city plan- ning, architecture, engineering, and related fields; and behavioral research is essential to understand why people elect to pollute and how they may be dissuaded from polluting. With population increase, restraints inevi- tably increase; acceptance of these re- straints will be necessary to preserve and nourish other freedoms. Atmospheric Contaminants and Development of Standards Atmospheric contamination can be considered on the global, national, state, regional, and local scales, each of which has its own vertical and temporal scales. (See Figure X— 3) The temporal scales have two aspects — the time-scale of the adverse effects associated with the contaminant, and the time-scale required for effective action for its control. These two time- scales tend to be similar in magni- tude for each of the horizontal scales noted above. One example of the global system is the postulated effects on the earth's temperature when carbon dioxide and particulate matter build up in the at- mosphere, affecting global heat bal- ance. Another example is fallout from testing of nuclear weapons in the at- mosphere. Neither of these problems can be resolved unilaterally by any one nation. Hence the time-scale for resolution is that of action by inter- national organizations. On the national scale, which in the United States is synonymous with the continental scale, we are concerned with the buildup of the background contaminant concentration of the non- urban air mass and with interstate transport of contaminants. Experi- ence has shown us that these take years to resolve. Within the confines of a state, our problems are those of urban-subur- ban-rural contaminant transport and reactions and of the impact of large, single contaminant sources on the land areas within their range of in- fluence. In such matters, we would expect a state to be able to initiate controls, if not effectively accomplish them, in a matter of months. In the United States, we are com- mitted to the regional concept of air- pollution control — the region being generally a multi-county area, either intra- or inter-state, which contains the principal sources of its pollution and the principal receptors adversely affected thereby. The principal time- scale with which a region must con- cern itself is the so-called air-pollution Figure X-3 — ATMOSPHERIC SCALES Horizontal Scale Vertical Scale Temporal Scale Global The Atmosphere Decades National The Stratosphere Years State The Troposphere Months Regional The Lowest Mile Days Local The Height of Buildings Hours "episode" — the build-up of pollution during a stagnation of horizontal and vertical atmospheric transport mecha- nisms extending over a matter of sev- eral days. Therefore, although the region may adopt a larger time-scale for attack on the basic causes of its contaminant problem, it must also be prepared to react to an occurring episode on a same-day or next-day basis. The smallest scale is that of the locality, covering several city blocks, in which traffic builds up for several hours each morning and afternoon. Our concern for atmospheric con- tamination globally is for the integrity of the earth as a planet on which hu- man life can exist without extinction by freezing, overheating, inundation, or starvation. Nationally, regionally, and locally we see atmospheric con- tamination as having adverse effects on our health, on vegetation, livestock, materials, structures, and the atmos- phere itself. All these elements of damage are associated with costs to society and to our economy; and all the means for control of contaminants have within them certain inherent costs. Our general view is that it costs us more to have pollution than to control it. Measuring Air Quality If one views air pollution as a sys- tem (see Figure X-4), we find that a convenient starting point is "Sources and Their Control." Our knowledge of the principal pollution sources and 332 AIRBORNE CHEMICALS Figure X-4 — A SYSTEM FOR DISCUSSING AIR POLLUTION STRATEGY FOR MR POLLUTION CONTROL SOURCES Al POL TACTICS FOR EPISODE CONTROL ID THEIR CONTROL AND THEIR EFFECTS i t AIR QUALITY STANDARDS EMISSION STANDARDS ■ SOURCES CONTROL METHODS ▲ POLLUTANT HALF- LIFE POLLUTANTS EMITTED EPISODE CONTROL TACTICS i 1 i i ' ' ' i • . ■ ' SOCIAL AND POLITICAL CONSIDERATIONS EMISSION ALLOCATION ALTERNATE PRODUCTS AND PROCESSES COST FUNCTIONS AIR QUALITY TRANSPORT AND DIFFUSION SOCIAL AND POLITICAL CONSIDERATIONS i I i i \ ■ ' ■ i i r~ AIR QUALITY CRITERIA SOCIAL AND POLITICAL CONSIDERATION COST EFFECTIVE- NESS DAMAGE FUNCTIONS AIR POLLUTION EFFECTS ATMOSPHERIC CHEMISTRY AIR ^ POLLUTION ^ POTENTIAL FORECASTS S ' ' The diagram shows a systems idealization of the problem of air pollution. Each box represents a set of problems about which we may know something, but certainly not enough to solve the problems or to understand exactly how that box may interact with other boxes. It is interesting to note the role of social and political considerations in the over-all air-pollution problem. They dominate our strategy and tactics for the control of air pollution. the means for their control is quite good, particularly with regard to the contaminants that are emitted to the atmosphere in greatest annual ton- nage — namely, carbon dioxide, car- bon monoxide, SOx, NO,, hydrocar- bons, and particulate matter. (In air-pollution parlance SCX and NOs mean a mixture of oxides.) Present knowledge of emissions that occur in lesser annual tonnage is less precise; and our control technology is fraught with economic problems. Some of our apparent control tech- nology has yet to be reduced to commercial practice because of the following dilemma: 1. Application of the untried tech- nology would represent a cost to the user that could be re- covered only by raising the cost of the product or service pro- duced. 2. Raising the cost of the product or service would adversely af- fect the competitive positions of the applier of the technology and will therefore be resisted unless required by law or sub- sidized by government. 3. There is a reluctance to require by law the application of an untried technology. This leaves governmental subsidy as the means to introduce untried tech- nology. As yet, we have made only halting steps in this direction. Once pollutants have been emitted, we are concerned with their fate in the atmosphere and the adverse ef- fects they produce. Their life history in the atmosphere starts with their transport and diffusion from their points of emission to their ultimate receptors, during the course of which they are subject to chemical reaction in the atmosphere and a host of scav- enging processes that tend to remove them from the atmosphere. The result of these several processes is measur- able at any receptor point in terms of the concentrations of the kinds and forms of contaminants that survive to reach the receptor. What we measure at a receptor point we call "air quality." Because of seasonal, diurnal, and microscale 333 PART X — ENVIRONMENTAL CONTAMINANTS variations in source strengths and character and in transport, diffusion, reaction, and scavenging factors, air quality will show considerable vari- ability. However, by increasing the averaging time of air-quality data, we can suppress enough of this variabil- ity to interpret the data meaningfully. Technological Shortcomings — There are scientific shortcomings in each stage of the process described above. The transport and diffusion phase takes place in the lower reaches of the atmosphere, above most ground-based instrumentation and be- low most aircraft and satellite-borne instrumentation. It occurs over popu- lous areas and in airport traffic pat- terns where we are not free to operate balloons, drones, towers, rockets, dropsondes, and other means of prob- ing the atmosphere for meteorological and pollution information. To the ex- tent that much of our measurement technology lacks sophistication, our knowledge of the phenomenon meas- ured falls short of the optimum de- sired. Because of the complexity of the potential chemical and scavenging reactions among all the pollutants present in the atmosphere, we have only scratched the surface of under- standing these phenomena. Our knowledge of air quality is limited, furthermore, to just a few places on earth that have been able to afford the installation and operation of air-quality monitoring equipment. Commercial vendors of such equip- ment have tended to await demand, with the result that there has been a proliferation of instruments to meas- ure a few well-publicized pollutants and a paucity of instruments for monitoring the less "popular" con- taminants. Data Base — We have given the name "air-quality criteria" to tabula- tions of cause-effect data relating var- ious concentrations of contaminants with the effects observed on people, vegetation, livestock, materials, struc- tures, and the atmosphere. These ob- servations encompass studies in the laboratory and the field and, in the case of people, involve epidemiologi- cal and clinical studies. Our "people" data is the weakest because airborne contaminants are only one class among many of stresses on population and the attribution of health effects to any one class is very difficult. Since these latter data form the basis for establishment of "air-quality stand- ards," and thus the base for regulatory control, they are the most contro- versial of all the data in the whole field of air pollution. The setting of "air-quality stand- ards," and the derivative establish- ment of "emission standards" to limit the emission of specific classes of sources, calls forth not only data from the physical and biological sciences, but also involves trade-offs and deci- sions that deeply involve the social and political sciences and interactions with other elements of the ecological and economic system. Decisions as to how we control air pollution can af- fect water and land pollution, and vice versa. Decisions on pollutant levels can affect the energy supply for our economy and reflect on the nationwide and worldwide trade in fuels. Considerable public contro- versy is likely, therefore, as to the desirable uniformity of air quality and national emission standards. Modeling — To help resolve some of these problems, mathematical mod- eling is increasingly being applied, both to the gross model of the whole air-pollution system and to more de- tailed models of individual elements of the system as, for instance, the transport and diffusion model. These latter models have been used exten- sively in setting the geographic boundaries of the "air-quality control regions" currently being designated by the federal government in various urban areas of the United States. What We Need to Know Data — More than anything else, we need to know the effects of pol- lutants in the atmosphere on the ex- posed population. Much of our past knowledge has been of the effects of certain pure substances on experi- mental animals or healthy adults. What we need is knowledge of how the mix of pollutants as they really exist in the atmosphere affects the actual mix of the exposed population. Technology — Our greatest air- quality measurement and monitoring need is for remote means of probing hundreds or thousands of feet through the air for an information return of pertinent chemical and physical data. In the area of control technology, our greatest need is to test prototypes and pilot plants preparatory to pro- duction and commercial action. Air-Quality Management — Fi- nally, we need better understanding of air pollution as a system, of the interaction within the system and be- tween it and other systems in the eco- logical and economic whole. In effect, we need to learn how better to man- age the air-quality system. Institutional Resources — To do these things requires trained people and facilities in which to train them. Much of the money that is now being spent in contract research could be better spent in building and equipping facilities for air-pollution research and training, preferably at universities, of a type that does not now exist in the United States. As an example, the Japanese government has built several large low-velocity wind tunnels for air-pollution research; in the United States, the federal air-pollution au- thorities have built none. All the large new smog chambers for the study of atmospheric chemical reactions are in the laboratories of private research organizations; they are not available for student training. The list could go on and on. Clearly, a redirection of effort is needed if tomorrow's prob- lems are to be solved. 334 Modeling the Atmosphere AIRBORNE CHEMICALS The purpose of the models in ques- tion is to allow quantitative assess- ment of "air quality" — i.e., the con- centration of pollutant gases and particles — at all or chosen points within an area of the order of 100 square miles which contains (and is bordered by) numerous pollutant sources. Models are required both for the assessment of abatement tactics (What sources are responsible for what degree of pollution in what areas?) and for the planning of de- velopment (What will be the effect of a new highway or new industrial com- plex on pollutant concentrations in the area and how, given that a pollu- tant must be emitted, can its impact be minimized by the siting of the source?). Existing models, when classified only according to the nature of their output, are of two types: short-term models and long-term models. The objective of a short-term model is to compute air quality averaged over periods of about one hour to one day. Long-term models produce averages of air quality over periods of one month to one year. Statistics of short- term averages of air quality may be derived from the output of long-term models by the application of empirical distribution functions. Long-term models are, therefore, applicable to planning and to assessing the broad impact of land-use changes on air quality; but if models are to be used in the day-to-day management of air quality — e.g., during air-pollution alerts and incidents — short-term models are required. Long-term aver- ages and statistics can, of course, be derived by the repeated use of short- term models, at the expense of com- puting effort. Physical and Mathematical Basis of Air Quality Models To compute the concentration of a pollutant, we must know where and in what quantity it is emitted and what happens to it in the atmosphere. If the source inventory is inadequate, the model cannot be expected to be adequate. An adequate source in- ventory must account for the total emission of pollutant over the area, and it must have the same resolution in time and space as the required out- put of the models, so that if we re- quire, for example, the one-hour aver- age concentration of sulfur dioxide (SO-) over an area one mile square, we must have an inventory of emis- sions of SOj hour by hour, averaged over areas not greater than one mile square. Once in the atmosphere, the pol- lutant travels with the wind. It may react chemically with other pollutants or normal atmospheric constituents, it may fall out or be washed out, or it may change by radioactive decay. Traveling with the wind is conven- tionally divided into transport by the average wind (the average being taken over times and areas larger than those resolved by the model) and diffusion by the turbulent eddies (i.e., by wind variations on time or space scales smaller than those resolved by the model). The mathematical basis of short- term air-quality models is the so- called continuity or conservation equation — a balance sheet of the pollutant in a box in space, with terms representing transport in and out by the mean wind, transport in and out by turbulent diffusion, emissions on the surfaces of and within the box (i.e., the "source inventory"), and chemical or radioactive transforma- tion within and deposition out of the box. Specification of the mean wind, the coefficients of diffusion terms, and the nature of the transformation, de- position, and decay is the task of the atmospheric scientist. Efficient or- ganization of the calculations calls for mathematical and computational skills. Solution of the continuity equa- tion is essential for a rigorous compu- tation of the concentration of pollu- tants produced by chemical reaction, such as the oxidants in photochemical smog, but no such model of an exten- sive area has yet been produced be- cause of the computational complexity of solving a set of simultaneous con- tinuity equations. The short-term models that have been successfully applied have been based on formulae that are formal solutions of a continu- ity equation with diffusion terms. Such solutions are typified by the "Gaussian plume" distribution of ma- terial continuity emitted by a point source. This has the form X(x,y,zJTL 2ttiJjUzu exp Mm where X is the concentration of pollutant at a height z, distant x in a direction along the mean wind and y in a direction across the mean wind from a source at height H emitting material at a uniform rate Q into a mean wind of strength u. The factors cry and o-Z/ which meas- ure the diffusive dispersion of the material in the horizontal and verti- cal directions, depend both on the meteorological conditions and on the distance from the source. They have been determined empirically many times and standard tables exist. Various integrations of this formula adapt it for use with line sources and 335 PART X — ENVIRONMENTAL CONTAMINANTS sources distributed uniformly over an area. Current air-quality models ap- ply these formulae to all the sources that contribute to the concentration within the chosen "target area" at the chosen time. They differ in the meth- ods by which they insure that only the essential minimum of computation is carried out. Performance of Air Quality Models The Gaussian-plume formula has been tested in many field trials in carefully observed weather conditions with controlled sources of a conserved pollutant. Using the standard meth- ods of estimating the diffusion param- eters of ) is accumu- lating in the atmosphere as a result of combustion of fossil fuels, and the amount of temperature rise to be ex- pected due to modification of the radi- ation balance has been estimated by theoretical computations. There has been some evidence adduced, less conclusive but nevertheless quite plausible, that concentrations of par- ticulates from pollution are likewise increasing on a worldwide basis. It has been suggested that the increase of particulate pollution tends to pro- duce a cooling which offsets or out- weighs the warming effect of CO2. Information is lacking on whether or not concentrations of other gase- ous contaminants, such as carbon monoxide, sulfur dioxide, and oxides of nitrogen, are similarly rising throughout the world. They probably are, since the removal processes for some contaminants, such as carbon monoxide, are much slower and less efficient than those for CO-. A gen- eral worldwide upward trend in these toxic substances would be of urgent concern. A rise in these background values means that the additional pol- lution emitted in urban and industrial areas would produce even higher local concentrations. Ultimately, such in- creases would lead to levels that ex- ceed thresholds for deleterious effects even at large distances from such areas. It is thus important to establish a network of monitoring stations to measure particulate and gaseous con- taminants at representative locations throughout the world, both in and near pollution sources, where almost all present measurements are made, and in remote locations where the background values will be obtained. Furthermore, it is important to meas- ure many contaminants, not just par- ticulates and sulfur dioxide, as is the case at most present-day monitoring stations. Thermal and Water-Vapor Pollu- tion— A further consideration is thermal pollution and water-vapor pollution. The effects of introducing large amounts of heat into the atmos- phere at industrial plants, particularly electric generating plants and in urban areas, are poorly understood. When cooling towers are used, and also in the combustion of hydrocarbons, larger amounts of water are intro- duced than would evaporate or tran- spire naturally. This addition of water vapor may have noticeable influence on the radiation balance (temperature effects) and on the occurrence of fog, cloud, and precipitation. Definitive studies of these effects are needed. 337 PART X — ENVIRONMENTAL CONTAMINANTS Alternative Courses of Action All of the above considerations are aspects of the general impact of tech- nology on the environment. The con- cept that technological development constitutes "progress" must be modi- fied so that all effects of the develop- ment are weighed, not just the profits to industry and the immediate benefit to the consumer. All the social costs, including the far-reaching conse- quences to the health of the commu- nity, the aesthetic properties of the environment (e.g., visibility), and the soiling of clothes and buildings, among others, must be figured in the benefit/cost ratios that are used to evaluate the desirability of a tech- nological change. The problems of conservation of natural resources and of waste dis- posal enter in an interacting fashion. Nonretrievable consumption of re- sources must be replaced as much as possible by recycling, in which wastes are retrieved and re-used rather than thrown away in the air, water, or soil where they constitute a pollution problem. The whole production-con- sumption organization of society needs careful study, to develop proc- esses that truly maximize social bene- fits and minimize harmful conse- quences. The corollary is that social, political, and economic organization of society will likewise require revi- sion, for under the present pseudo- laissez-faire situation long-range ef- fects will not be given priority over immediate profits in determining the course of action. Much of the impact of man on the environment has arisen because, as a result of technological advances, the human population has increased ex- ponentially. This increase cannot go on. Even with exploitation and even- tual degradation of every part of the earth, a point must be reached when food, air, and water are inadequate to support one additional person at the lowest level of subsistence compatible with life. Figure X-5 illustrates some of relevant variables. We can hope that this stage will never be reached. We should strive for a stabilization of the population at a level at which the quality of life, as sustained by the quality of the environment, is not merely tolerable but truly enjoyable. It has been suggested that man will adapt to a polluted environment, just as organisms in general adapt to sur- rounding conditions by evolutionary processes. However, the changes pro- duced by technology have been too rapid for evolutionary processes to cope with. Long before mutations produce humans whose blood rejects carbon monoxide — rather than hav- ing it combine to form carboxyhemo- globin, which limits the transport of oxygen by the blood — the accumu- lation of carbon monoxide and other toxic substances in the atmosphere may make man extinct. One alternative is technological adaptation: development of appropri- ate gas masks, air-conditioned homes and vehicles, or even enclosures of entire cities in which the air is proc- essed to remove toxic substances and protect man from the poisons he puts into the surroundings. But surely it is more sensible to use technology to avoid putting the contaminants into the atmosphere than to apply it to processing the air to remove them be- fore we breathe it. Figure X-5 — PROJECTION OF PHYSICAL, ECONOMIC, AND SOCIAL RELATIONSHIPS POPULATION 2100 The graph shows five physical quantities"plotted on different vertical scales, but combined in the same graph to emphasize their relationship. The variables and their units, projected to the year 2100, are: population (total number); industrial output per capita (dollar equivalent per person per year); food per capita (kilogram- grain equivalent per person per year); pollution (multiple of the 1970 level); nonrenewable resources (fraction of 1900 reserves remaining). Although the model is at best only a first approximation containing many assumptions and gaps of knowledge and data, it does suggest some of the factors that could combine to limit world growth. 338 2. AIRBORNE BIOLOGICAL MATERIALS Atmospheric Dispersal of Biologically Significant Materials An Aerobiology Program has been established within the International Biological Program (IBP). The United States Aerobiology Program under the IBP has been in operation about two years. It is the strongest national aerobiology program, with the Neth- erlands nearly as active. International collaboration is growing steadily. The activities of the Aerobiology Program are generating new ap- proaches to studies of biologically sig- nificant materials in the atmosphere, such as spores, pollen, fragments of algae and molds, minute insects, and toxic particles and gases. Until now studies of these materials in the at- mosphere have been done in highly individualistic ways, with almost no comparison of work by different au- thors and no theoretical bases for guiding research and organizing the resulting information. There are a few notable exceptions, such as the well-conceived bodies of research in the 1930's and 1940's by Stakman and Harrar on cereal-rust epidemiology on the North American plains. But now there are new pressures to guard food crops against losses, to reduce human disease, to curtail additions to atmos- pheric turbidity, to clean air of nox- ious pollutants, and many other tasks involving atmospheric dispersal in ecological systems, all of which are objectives to which aerobiologists can contribute. (See Figure X-6) The science of meteorology has be- come "systems ordered," from the research-planning to the data-han- dling phases, and is fast becoming coordinated on a worldwide scale with respect to observations. Now is a propitious time for aerobiologists to link up with meteorologists for the mutual benefit of their researches and Figure X-6 — ATMOSPHERIC PARTICULATE MATTER IMPORTANT IN AEROBIOLOGY Diameters (meters) 10 > 10 ' Commonly Used Units 001u 01u (microns, millimeters & centimeters) 10- ,lu Fall Speeds (cm/sec) _Browman movement 1(H lu .003 io-5 lOu 10-" 10-3 io-? lOOu 1 mm 1 cm 30 .300 ation Permanent Suspension -• — (Gravitational fallout is not significant) ■ Smokes - Transition_ Region Dusts (fine) Transient Particulates (only strong winds can sustain these in the atmosphere) Dusts (coarse) Haze particles ■ Condensation nuclei Viruses *- -» Bacteria Algae -— Protozoa Fungus "*" spores " Lichen fragments Moss spores" Pollen Fragments of plants, seeds, insects, & other microfauna The table gives some physical properties of particulates encountered in aerobiology — diameter, expressed in meters and other commonly used units, and approximate terminal fall speed. From an aerobiological point of view, smokes, fine dusts, haze particles, condensation nuclei, viruses, bacteria, and algae are the atmospheric particulates of greatest concern. This is because gravity does not cause them to fall out of the atmosphere as do most of the heavier particulates in the lower-right- hand part of the table. Instead, they are deposited on surfaces by impaction or are washed out by precipitation. 339 PART X — ENVIRONMENTAL CONTAMINANTS for aerobiology to derive out of that association help in developing a theo- retical framework based on ecological systems approaches. A planet-wide network for moni- toring ecological systems is clearly essential to the human welfare. We need both warning systems that will permit measures for reducing or avoiding injury to ecological systems, and prediction capabilities wherein the potential for injury is shunted aside or eliminated before risk of in- jury arises. These will inexorably re- quire baseline data against which to measure change, which suggests that we should establish monitoring sta- tions immediately. One of the most feasible systems to begin with is one for monitoring ma- terials in the atmosphere. Much of the technology for sampling gases and particles in the atmosphere is at a stage of acceptable reliability, and basic stations and networks already exist for observing and measuring fundamental physical parameters. Ex- tensive and costly efforts are already applied to counteract the diseases of plants and animals by airborne agents, human allergies resulting from air- borne materials, and insect pests car- ried on winds. The necessary data base is less well ordered, however. There is an abund- ance of information about spores of common plant-disease fungi (smuts, rusts, and the like), and there is a considerable literature on atmospheric pollen sampled by allergists and paly- nologists. But only scattered studies of other particles of biological origin have been done, and the information on biological particles in general is in an almost completely unordered state. Some good survey data exist on radio- nuclide particle fallout, but only scat- tered data of widely different relia- bilities concerning other inorganic particulates. Local observations on certain polluting gases have been faithfully recorded for ten years or more in some cities, but the informa- tion is mostly uncorrelated with ob- serving stations in other cities or with other phenomena. In short, virtually all of the data on dispersal of biologi- cally significant materials in the at- mosphere is unordered, and there is no data system prepared to receive, let alone store and retrieve it. By contrast, meteorological data are well ordered and handled in the framework of systems analysis guided by adaptable theory. Furthermore, as consequences of the several Interna- tional Geophysical Years and agencies such as the World Meteorological Or- ganization, meteorology is organized on a worldwide basis. The aerobiolo- gists can profitably take some cues from the meteorologists. There follow comments on six ma- jor problem areas of aerobiology — the systems approach, plant and ani- mal diseases, airborne allergens, ur- ban and indoor environments, insects and other microfauna, and phytoge- ography and genecology of "aerial plankton." A concluding section treats the current efforts in aerobi- ology and prospects for the future of the science. Systems Approach to Aerobiology There is abundant information on movements of biological materials through the atmosphere. Nearly all attention to this topic has been ad hoc and empirical, however. The time has come when the aerobiologist, the me- teorologist, and the applied biologist (e.g., agronomist, forester) or engineer (e.g., sanitation officer, industrial de- signer) should work together system- atically on problems of predicting the time, place, and probability of deposi- tion of given material from the atmos- phere. The objective should be to develop functional models of the mul- tiple-parameter problem of the entire process — particle formation, release, takeoff, aerial trajectory, scavenging or deposition, germination (if viable), and effect on biota or environment — so that prediction is based on all ob- servable parameters, with standard- ized criteria for observations and measurements. (See Figure X-7) Development of such models will provide schemes for ordering existing information and storing new informa- tion in a re-usable and retrievable form. If the models are to have con- tinued and improving usefulness, they must also be suited to feedback cor- rections so that new information and new solutions improve the validity of the models. Research Needs — This is a diffi- cult set of theoretical and technical problems from the standpoint of both biology and meteorology. Continued and intensified study of the biology of spore formation and release, ques- tions of survival of living material under different atmospheric condi- tions, problems of host specificity and conditions favoring epidemics, and similar matters are needed. From the meteorological standpoint there is need for development of joint prob- ability meteorological statistics con- nected with the favorable conditions for spore release, quantitative trans- port, and the optimum infection "climate." Recent advances in measurements of the planetary boundary layer and, in particular, the wind, temperature, and humidity profiles in the near sur- face layer promise to permit estimates of the critical parameters both from direct measurements and inferences from large-scale meteorology. Espe- cially promising is the development of numerical prediction models from which three-dimensional trajectories of material can be calculated; the direction and speed of transport of the material can be forecast 72 to 96 hours in advance with steadily im- proving accuracy. In the absence of current studies to evaluate the frequency of favorable conditions and the subsequent occur- rences or non-occurrences of infec- tions, the ability of a total biological- meteorological-agricultural warning system to provide usable and depend- able predictions remains to be deter- mined. Contributions toward solving these general problems are increasing. 340 AIRBORNE BIOLOGICAL MATERIALS Aerobiology of Plant and Animal Diseases Figure X-7 — COMPONENTS OF A MODEL FOR POLLEN AEROBIOLOGY Geographic Plant Distribution Antecedent Sun and Rainfall "^ Catastrophic Events PRODUCTION Pollen Maturation EMISSION Day Length REFLOTATION DISPERSAL Settling Rates Wind Structure DEPOSITION Temperature Structure Retention by Substrate Age Distribution in Stand Genetic Pollen Production Potential Morphology of Flower for Emission Rainfall Sunshine Relative Humidity Atmospheric Turbulence Pollen Morphology, "Flight Characteristics" Shapes of Plants Vertical and Horizontal Patterns Physiography h Microclimate, Wind Speed Temperature, Structure, Turbulence Rainout Atmospheric Factors Any scheme for modeling, and hence prediction, of pollen concentration must include the many factors shown in the diagram, in approximately that relationship. There are unanswered questions at many points in this conceptualized model, so that accurate predictions of pollen concentration at any point in space and time will not really be available with any degree of accuracy in the near future. Plant Diseases — The supply of the world depends or crops, every one of which is subject to diseases or pest attacks that can and do prejudice entire crops over regions of considerable size. (See, for exam- ple, Figure X-8) For cereal-grain crops, the answer to rust and smut diseases has been to continue to breed resistant strains, each of which has a useful life of one or two decades, until the parasitic organism develops a form that overcomes the resistance of the host. Can this go on indefinitely, especially since populations of wild ancestors of these horticultural species are disappearing? For some fungus diseases of crop plants, prevention is exercised by re- stricting culture to certain climates or special soils. In other instances chem- ical inhibitors of fungus growth are administered. Similar measures are used against insect pests and sucking insect vectors of virus diseases. The inocula for these diseases and pest attacks are in most instances carried passively by the atmosphere. But only in a few instances do we know in what quantities, in what directions, and with what survival as viable en- tities the inocula are transported and deposited. The "triangle of epidemiol- ogy"— origin, transport or vectoring, and infection — thus depends heavily on information about atmospheric transport. We could learn much about probabilities for transport of many kinds of organisms through full knowledge of the transport of a few that we can readily collect in transit, identify with certainty, and test re- liably for viability. It has been found appropriate for aerobiology, at least in the context of the IBP, to take under its wing certain studies of diseases that are not con- fined to atmospheric transport consid- erations. From an ecological view- point, diseases of crop plants are exaggerations of natural situations be- cause of ecological imbalances intro- duced by agricultural practices such 341 PART X — ENVIRONMENTAL CONTAMINANTS Figure X-8 - AVERAGE ANNUAL LOSSES FROM CROP DISEASES IN THE UNITED STATES Commodity Group Loss from potential production % Value Reduction (in '000 dollars) Field crops 13% $1,890,836 Forage crops and pasture ranges 11 808,701 Fruit and nut crops 16 223,505 Ornamental plants and shade trees 12 14,099 Forage seed crops 14 23,584 Vegetable crops 13 2,990,839 Total 13 3,251,114 The figures in this table represent potential production in the U.S. from 1951 to 1960, inclusive — i.e., the production that would have been realized had plant diseases not been present. Most of the losses are due to rusts, smuts, viruses, fungi, and molds that are viable biological material transported in the atmosphere by the wind. as extensive acreages of monocultures, wide use of genotypically identical populations, unusual growth of foli- age or fruit through use of chemical fertilizers and irrigation, and elimina- tion of associated and competing species. Some aerobiologists see op- portunities to study the cultural checks and balances of plant diseases at the centers of origin of the crop species, and also opportunities to learn about pathogenic germ-plasm variability, survival, and migration. Out of such studies of "origins and sources" of plant diseases the United States Aero- biology Program is endeavoring to de- rive new biological information that will constitute improved input for the epidemiological models described above. Human and Animal Diseases — Al- though various human and animal diseases are spread by transmission of bacteria, spores, or viruses in the air, most of the atmospheric transport is probably over a short distance and within a water droplet or on some other particle. Studies of these par- ticles have been confined to indoor air, especially of hospitals. However, a number of pulmonary mycotic dis- eases are acquired by the inhalation of spore-laden dust or other organic particles in the free air indoors or outdoors. Histoplasmosis, coccidioi- domycosis, North American blasto- mycosis, cryptococcosis, and nocari- dosis may result from exposure of humans or animals to such infec- tious materials. The fungi or fugus- like microorganisms causing these diseases are unique in that they are free-living in nature but also find the susceptible mammalian body a suit- able growth environment. In a small percentage of cases, the infectious agent disseminates from the pulmo- nary tract involving a multiplicity of organs and tissues. From knowledge accumulated to date it appears that some of these etiologic agents exist in certain foci in nature and are often associated with avian or chiropteran species. Some of these agents also exist in sharply demarcated geographical areas, such as a portion of a (Milan, Michigan) schoolyard which was a source of histoplasma infection. In- fectious particles become airborne due to winds or mechanical disturbance of soil in which the fungi are present. Most of the work on control has been directed toward eradicating the infec- tious agent by chemical sterilization of its natural habitat. Some studies have been made on the ecology of these fungi, but much more work re- mains to be done. Airborne Allergens Allergenic pollen and spores in the atmosphere have been under study for nearly fifty years as clinical prob- lems, with varying degrees of atten- tion to botanical sources and phenol- ogy of the airborne particles. Greater uniformity in air sampling and report- ing techniques, and better organiza- tion and availability of accumulated information on the distribution of allergenic particles, are clearly neces- sary for improved prediction of ex- posure. Improvements of these kinds are in progress nationally and inter- nationally, fostered by appropriate organizations including the IBP Aero- biology Program. Research Needs — Especially in connection with urban areas with high levels of gaseous pollutants in the at- mosphere, there is need for investiga- tion of possible interactions between biological (spores, pollen, fragments of fungus mycelium, and similar ma- terials) and nonbiological (gases such as sulfur dioxide, hydrogen fluoride, and so on) emissions in transit. Fur- thermore, the extent to which these two groups of agents may induce synergistic effects on plants and ani- mals is a subject that merits further attention. Regarding atopic allergy, there is strong suggestive evidence that augmented respiratory changes due to simple gaseous irritants may be expected in persons with preexist- ing inflammatory changes due to ex- posure to inhalant or ingestant aller- gens. The concept is growing that specific segments of the general popu- lation may be predisposed to experi- ence adverse effects from air pollu- tants; it would be valuable to explore 342 AIRBORNE BIOLOGICAL MATERIALS the possibility that aeroallergens may exert such a selective influence. An additional aspect of aerobio- logical health effects that seems to warrant study relates to possible (nonspecific) irritant effects of bio- logical particulates due to vasoactive materials carried by them. Cultures of certain hyphomycetes (molds that produce conidia on loose, cottony hyphae) do synthesize such agents, and it would be useful to know whether airborne spores could do so in the concentrations encountered in nature. Many "allergic" persons re- port "irritation," hoarseness, and mu- cous membrane burning following massive exposure to fragments of fungi (e.g., while raking leaves), sug- gesting the possible action of chemical irritants. Possible direct interactions of eluted materials with the human respiratory flora might also be ques- tioned, since purulent bacterial infec- tion often follows rapidly on such exposures. Present Urgency — The recognition that precipitating antibody-mediated reactions to biological agents can pro- duce systematic effects and granulo- matous lung disease (i.e., farmer's lung, bagassosis, maple-bark disease) provides new incentives for exploring and characterizing the breadth of bi- ological materials in free air. The dearth of even preliminary informa- tion regarding incidence and variety of bacteria in free air (apart from hos- pital wards and operating rooms) is distressing. Similarly, background knowledge and general techniques are at hand for making studies of algal, actinomycete, and protozoan bodies in the "aerial plankton," but scarcely a beginning has been made. Study of algal, insect, and acarid material in air will require development of meth- ods for identifying these components either as individual particulates or as components of bulk samples. Aerobiology of Urban and Indoor Environments Assemblages of species and mate- rials in the atmosphere of the urban environment are markedly different from rural and wild landscape as- semblages. Outdoor Environment — One com- ponent in urban air has been derived from the local region or from even wider areas, depending on the char- acteristics of the particles for remain- ing airborne. Atmospheric concen- trations of rust and smut spores from agricultural lands come into urban areas in only slightly reduced num- bers. In addition, the urban pollen spectrum is dominated by street and park trees (elm, oak, ash, pine, birch, mulberry) and weeds of alleys and vacant lots (grasses, lambs-quarters and pigweeds, and the ragweed group). There are greatly increased local concentrations of mold spores (conidiospores, conidia, etc.), frag- ments of algal colonies, and "organic trash" that tends to accumulate in nooks and crannies in masonry and asphalt where normal processes of humification and recycling are ineffec- tive in disposing of it. Soil surfaces, even in the heart of a city, are prob- ably helpful in taking some of these offensive dust components out of the air and converting them into an in- nocuous humus component of the soil. However, there are only limited soil surfaces in the hearts of cities. Indoor Environments — Inside dwellings and industrial buildings there are entirely unique and ex- tremely varied assemblages of air- borne materials, as one would expect. Old wooden buildings accumulate wood-rotting fungi, molds, and in- sect and mite populations that make up "house dust," to which certain persons are very sensitive. It was recently reported that North Ameri- can and European house-dust mites (Dermatophagoides spp.) were found in dusts used for commercial extracts in treatment of allergies. Masonry buildings, especially in damp climates, develop mold fungus and algal col- onies that populate moving air with spores and fragments. In these struc- tures, parts of dead spiders, mites, insects, and other organic matter become mixed with fungus n to form various substrates for bac- terial decay or, in larger masses, site for insect, mite, or milliped colonies. Very little specific attention has been given to the airborne plant and animal material of indoor environ- ments. Questions arise with regard to saprophytic, or at least non- invasive, organisms, since reactions to these involving skin sensitizing and precipitating antibodies or de- layed (cell-mediated) hypersensitivity may be involved etiologically in dis- eases presently of unknown origin. Evidence from sampling strongly sug- gests that domestic humidifiers pose a real hazard for fungus-sensitive patients; careful investigations of in- door allergens is warranted. Forced ventilation through ducts that are not periodically cleaned is a potential source of continuous dispersal of spores, mycelia, and dust. The longer the occupancy, the greater the accu- mulation of offending materials. Al- lergists in the United States and Europe are increasingly interested in these aspects of indoor environments. Recent reports of a small epidemic of severe lung disease due to thermo- philic antinomycetes (probably Mi- cromonospora sp.) contaminating a commercial air-conditioning system underscore the potential value of work in this area. Atmospheric Dispersal of Insects and Other Microfauna Transport of insects and other very small animals by wind is proving worthy of special study, not alone for the biogeographical implications but because of the inherent potential- ity of pest epidemics and vectoring of diseases. In regions where alfalfa and mixed hay crops are grown, sum- mer winds and disturbance by mow- ing usually launch great numbers of leaf hoppers, spittle bugs, and other small sucking insects into the air. Once airborne, these insects are car- ried as much as 100 miles downwind, where they settle down on new crops, 343 PART X — ENVIRONMENTAL CONTAMINANTS in some instances transmitting plant viruses they brought with them. The U.S. Department of Agriculture has worked out many of the disease- transmission possibilities, but we do not yet have enough coordinated ob- servations to be able to assess the significance of such insect transport. In the tropics, vectors such as the tsetse fly generally show patterns of narrower endemism, and this should be studied against the possibility of human activity inadvertently creating favorable conditions for a dangerous vector in a new area. There is clearly need for assessment of existing knowledge in this area and an effort to determine efficient courses for further action. "Aerial Plankton" in Relation to Genecology and Phytogeography A neglected but obvious functional aspect of the aerial transport of pol- len and spores, and of all other par- ticles that are propagules, is that this process represents transfer of genetic material from one geographic area to another and, in the event of germi- nation on the new site, injection of more or less different genetic material into a population. If we are to under- stand the ecological genetics, or "gen- ecology," of populations, quantitative as well as qualitative aspects of at- mospheric dispersal of viable prop- agules and pollen must be studied. Applications having considerable eco- nomic importance will follow closely in such activities as breeding of hy- brid crop plants and forest trees. In the course of observing aerial transport of viable propagules, we should be on the lookout for those that would have come from a distant source. This evidence would help to resolve many old arguments for or against long-distance transport as ex- planations of wide disjunctions of range. Wind transport of humus and other organic material out of one eco- system unit and into another has become a matter of concern to ecol- ogists studying productivity in detail. They find this export and import of materials and energy attaining sig- nificance in the production budgets of climates that are dry and windy, at least for seasonal periods. Aero- biologists are currently trying to help the ecologists of the IBP Grassland Biome Project in Colorado to obtain reliable measurements of amounts of material in transit at given times and accumulating on different sites over specific time intervals. Historical Studies — "Microfossil" pollen grains, spores, diatoms, and other small and identifiable organic particles in sediment have been used for over half a century to obtain stratigraphic correlations and paleo- ecological reconstructions. The most detailed and refined uses are made of late Quaternary microfossils be- cause they are so nearly like the living forms of which we have first- hand knowledge. Several aerobiolo- gists are endeavoring to identify strategically located sedimentation sites and airborne biological forms accumulating in them today in order that the older sediments might, in effect, extend the baseline for envi- ronmental monitoring back in time some hundreds or thousands of years. Opportunities may present them- selves for linking in time the changes indicated by airborne particles with changes indicated by aquatic-system elements. Some inland lakes are known to have sediments that are annually banded, so that precise dates can be obtained for the record of the past. One such lake in Minnesota has nearly 10,000 annual bands in its sediments. Prospects for Aerobiology In his book Microbiology of the Atmosphere, Gregory stated: Our knowledge of the terrestrial air-spora is fragmentary in the extreme. The air has never been systematically explored simultane- ously in different parts of the world by comparable methods. There is a heap of accumulated data. . . . Here and there are in- triguing suggestions of phenomena; but many of the data are unin- terpretable, and we need a fresh study of aerobiology as part of a vast terrestrial process. The IBP Aerobiology Program is ini- tiating just such efforts as a transient, first step. It has sponsored, jointly with the Environmental Protection Agency, a conference entitled "Aero- biology Objectives in Atmospheric Monitoring," at which meteorologists and aerobiologists drew up the first lists of priorities for information ac- quisition and assessed the practicali- ties of sampling and data processing. These people will look ahead to inte- grating these activities into the pro- posed GNEM (Global Network for Environmental Monitoring). The prospects are that support for world- wide environmental monitoring, in aerobiology at least, will be well re- paid by the benefits realized. The Secretary-General of the United Nations is calling for an inter- national body that will supervise sentinel and warning stations for detrimental changes in environments and biota all over the earth, and the plans for the GNEM constitute the preliminary blueprint. ICSU (Inter- national Council of Scientific Unions) and its member organizations — IUBS (International Union of Biological Sciences), in particular — are ready- ing a larger scheme, called the "Man and the Biosphere" program, designed to interpret the changing conditions for man and the organisms sharing the earth and supporting him, and to plan for improvement of conditions for human life in the future. For at least the decade of the 1970's, organizations serving aerobio- logical needs must be kept adaptable and responsive to widely different 344 AIRBORNE BIOLOGICAL MATERIALS opportunities. This argues for a small, volunteer steering group, rep- resenting diverse interests in aero- biology and dedicated to international cooperation. This steering group should have membership from gov- ernment, academic institutions, and appropriate industrial organizations. A large, monolithic research organi- zation does not seem appropriate, but provisions must be made for receiv- ing, processing, storing, and i information, hopefully by a mode; addition to some established data center. Biological Monitoring Techniques for Measuring Aero-allergens Diseases caused by inhalation of airborne biological particles have long been recognized as important public health problems. These diseases, commonly termed hay fever or polli- nosis, are estimated to affect about 10 percent of the U.S. population (a much greater percentage than are known to be medically affected by all man-made air pollutants) and some- times develop into more serious dis- eases such as bronchial asthma. In addition to causing considerable dis- comfort to affected individuals, these diseases cause a substantial economic loss in terms of time lost from work or school, lowered efficiency, and di- rect medical costs. These diseases are most frequently caused by pollens from anemophilous plants and by a few groups of fungus spores, but other known or potentially allergenic airborne biological particles include spores from ferns and mosses, algae, plant hairs, and insect scales. Aero- allergens vary greatly in size, shape, density, and other physical character- istics, but many are more or less spherical and most have dimensions between 1 and 100 microns. Aeroallergens are commonly sam- pled from the atmosphere to deter- mine their presence or absence, relative abundance, spatial distribu- tion, and both seasonal and diurnal patterns of occurrence. Past studies have given considerable qualitative information for a few common par- ticles such as ragweed pollen, but few data have been obtained for many known or potential aeroallergens. Until recent years, sampling devices capable of giving a quantitative meas- ure of concentration for particles in this size class did not exist and even today are little used. However, ac- curate concentration measurements are necessary for such important studies as the following: 1. Determination of the spatial and temporal changes in dis- tribution of each important aer- oallergen and the relationships of such changes to meteoro- logical and other factors. 2. Studies of the relationships be- tween aeroallergen concentra- tions and the onset or severity of allergic symptoms in suscep- tible patients. 3. Evaluating the success of medi- cal treatments. 4. Planning and evaluating the results of weed control or eradi- cation programs. 5. Documenting changes in aero- allergen concentrations caused by changing land-use patterns and urbanization. 6. Determining the seasonal and diurnal emission patterns from sources of aeroallergens and relating these patterns to other variables. 7. Determining the efficiency of particle-removal mechanisms such as washout by precipita- tion and impaction by vegeta- tion. 8. Determining possible syner- gistic effects between aeroaller- gens and other air pollutants. Despite the obvious need for more study of aeroallergens, such research has been hindered by the difficulty of obtaining accurate and representative samples of these airborne particles and by the tedious methods that must be employed to identify and count the samples collected. Evaluation of Current Scientific Knowledge Nearly all research on aeroaller- gens and their relationship to man depends on sampling devices and techniques, but the accuracy of such sampling devices is critically depend- ent on the characteristics of the par- ticles they are employed to sample. Data Base — Information on the characteristics of aeroallergens is far from complete. Although the size and shape of airborne pollens are generally known, little useful infor- mation exists on their density. The size and density of some pollens are known to change with age or with changes in humidity, but few meas- urements are available. For example, it is not known whether the bladders on conifer pollens are inflated or de- flated while airborne or whether this varies with conditions. Information on fungus spores is more sparse; no density determinations seem to have been made, and many spores sampled from the atmosphere cannot be iden- tified as to source species. Even less information is available on other ac- tual and potential aeroallergens. The sources of airborne pollens are generally known as to geographic re- gion and habitat (see Figure X-9), 345 PART X — ENVIRONMENTAL CONTAMINANTS Figure X-9 — DISTRIBUTION OF RAGWEED POLLEN IN THE UNITED STATES Ragweed pollen is responsible for more than 90 percent of all the pollinosis in the United States. Some 50 species of ragweed are known; they are found in all fifty of the United States, but the highest concentrations are in the North Central and Northeastern states. They grow alongside highways, in plowed fields, and in other disturbed areas. Since there is more and more disturbed soil each year, there is more and more ragweed, and, hence, there are more and more pollen and hay- fever sufferers. but the location of local sources that affect specific receptors is often not known. Seasonal patterns of occur- rence are fairly well documented for most important species, but diurnal patterns have been studied for only a few, and the relationships between these patterns and other variables are little known. Sources of fungus spores are less well known than sources of pollen, and diurnal and seasonal spore concentration patterns have seldom been studied. Although the dispersion mecha- nism plus the source strength will determine the concentrations that are sampled at any given point of inter- est, quantitative studies of pollen transport and dispersion from known sources have been made by only two research groups in this country. These studies have indicated that pollens are dispersed much like inert particles of similar size, and that meteorological diffusion theory may be applied if particle characteristics, source configuration, and output rate are known. Concentrations of aeroallergens at sampling locations may vary by at least several orders of magnitude. Close to a local source, such as a field of ragweed, concentrations can average over 75,000 grains per cubic meter during a several-hour period. Short-period peak concentrations probably exceed this value by several times. At locations distant from 346 AIRBORNE BIOLO' KIALS sources, ragweed pollen concentra- tions seldom exceed 200 grains per cubic meter during the emission sea- son. Other aeroallergens also vary greatly in concentration, and certain fungus spores are often present in great numbers. These variations in concentration lead to difficulties in choice of sampling methods and pe- riods. An efficient sampler may over- load in the presence of high concen- trations, while an inefficient one may not take an adequate sample if con- centrations are low. The Limitations of Sampling Meth- ods — Obtaining a sample of air- borne particles in the aeroallergen size range may be accomplished by many samplers, but obtaining an accurate or representative sample over all size ranges commonly present is a difficult problem not solved by any sampler in current use. In fact, it can be stated categorically that no single sampling method so far devised is capable of obtaining a representative sample of all aeroallergens from the free atmosphere and that no perfect sampling method exists for any. The principal cause of difficulty in sampling particles in this size class is the momentum that they acquire in moving air as a result of their mass and velocity. This inertia causes their path to deviate from that of the sur- rounding air if that air is forced to change speed or direction, as by a sampling device. With the exception of isokinetic sampling, which has not yet been perfected for use in the free atmos- phere, sampling methods in which air and, hopefully, its entrained particles are drawn into an entrance or orifice tend to be inefficient for large parti- cles since these often fail to follow the airstream into the entrance. Since momentum increases with particle size, particle density, and air speed, it follows that such samplers are not only size-selective but vary in entrance efficiency with wind speed. In general, methods of removing from the airstream those particles that do get into the entrance are satis- factory. These methods include fil- tration, impaction, liquid impinge- ment, and electrostatic attraction. Suction-type samplers are sometimes used for sampling aeroallergens, but cannot be recommended except for the smaller fungus spores. The most common device for sam- pling aeroallergens is a microscope slide coated with adhesive and ex- posed horizontally, usually between rain shields. This "gravity-slide," or "Durham" sampler, collects by tur- bulent impingement and gravitational settling, but is generally unsatisfac- tory since the volume of air sampled cannot be defined and the catch is a function of wind speed, turbulence, and wind direction relative to the long axis of the slide as well as the concentration of particles and their characteristics. Although still in wide- spread use and of some value for qualitative purposes, it should be re- placed by other samplers where quan- titative measurements are desired. To date, the most satisfactory de- vices for sampling aeroallergens are those which collect by impaction. Here, the momentum of the particle is used to effect its capture; efficiency increases as particle size, particle den- sity, and wind speed increase. How- ever, efficiency of wind impactors does vary with particle parameters, so that each particle of interest is likely to be sampled with a different efficiency and the efficiency for all will vary with wind speed. In gen- eral, samplers of this nature must be accompanied by a sensitive ane- mometer, and the catch corrected for sampling efficiency. An advantage of wind-impaction methods is that im- paction efficiency can be computed mathematically for certain simple geometric shapes like cylinders and spheres if impactor dimensions, par- ticle parameters, and wind speed are known. For a given collector and a single particle type, impaction ef- ficiency can be calculated and graphed as a function of wind speed. (See Fig- ure X-10) Total collection efficiency, however, depends on both and retention efficiency and ad< adhesive must be used on collecting surfaces to insure good retention of impacted particles. Wind-impaction samplers are usually cylindrical in shape and are commonly mounted on a wind vane so that the sample is taken only on one side. Such sam- plers have normally been used only in controlled research programs and are not recommended for general use. The disadvantages of wind-impac- tion samplers were largely overcome and their advantages retained by the development of powered impaction devices such as the rotorod, rotobar, and rotoslide samplers. In these, the sampling surfaces are rotated through the air at a high rate of speed, giving virtually constant impaction efficiency for any given particle type. Al- though efficiency may still vary with particle size and density, it is gen- erally much higher than for wind- impaction samplers. Adequate reten- tion requires a thicker or better ad- hesive, since particles impacting at a high rate of speed tend to bounce off. Since the efficiency of these devices is high and their sampling surfaces small, overloading becomes a problem during prolonged sampling periods at commonly encountered concentrations. This problem is over- come by sequential or intermittent sampling, but the sampling surfaces must be protected from wind im- paction when not rotating. Several methods have been devised for this purpose. Rotating impaction sam- plers are the most satisfactory sam- pling devices now available for most aeroallergens and are being used by an increasing number of allergists, public health agencies, universities, and research groups. Aeroallergens collected on sam- pling surfaces are commonly identi- fied and counted using an optical microscope. Routine counting of a single particle type such as ragweed pollen may be readily accomplished by unskilled workers, but critical identification of many pollens and 347 PART X — ENVIRONMENTAL CONTAMINANTS Figure X-10 — EFFICIENCY OF CYLINDRICAL COLLECTORS FOR RAGWEED POLLEN 100 80 70 60 Ml 40 30 20 10 One mm, diameter cylinder One mm. middle section of one-fourth inch diameter cylinder > One-fourth inch diameter cylinder 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 WIND SPEED IN METERS PER SECOND The graph shows a plot of impaction efficiency in percent versus wind speed in meters per second for three different-sized cylinders. The smaller the diameter of the collecting cylinder, the higher the impaction efficiency because the stagnation region in front of the cylinder is physically smaller and the particles need less inertia to penetrate it. To overcome the variability in wind speed and wind direction in nature and to operate the samplers at optimum impaction efficiency, samplers are rotated to simulate wind speeds of 10 meters or more per second. spores requires highly trained ex- perts. At times, concentrations, not only of the species of interest but also of other materials, may be so high that counting becomes difficult and time-consuming. This problem is multiplied when samples are counted for many or all species pres- ent. Visual counting is a tedious chore at best, but automatic counting devices have not yet proved their ability to differentiate and count aeroallergens. Representativeness — Aeroaller- gens are commonly sampled at a single point over some pre-selected time period, often twenty-four hours. The spatial representativeness of single-station sampling has been little investigated, but it is known that proximity to sources, elevation above the ground, and presence of obstacles to airflow can produce wide differ- ences in catch over short distances. Even two identical samplers operated side by side may often differ by 10 to 20 percent and sometimes by 50 percent. If concentrations are meas- ured over some time period, they may not represent concentrations over ei- ther a longer or a shorter time period. Thus, even a perfect sampler could only measure the mean concentration over some time period at a specific location; extension of the measure- ment to other locations or periods would be accompanied by some un- certainty. Requirements for Scientific Study Sampling of aeroallergens, study of their behavior in the atmosphere, correlation of their presence and abundance with other pertinent vari- ables, and application of the knowl- edge gained to the pollinosis problem would be greatly facilitated by the development and use of better sam- pling devices. An ideal sampler would sample the atmosphere non- selectively, capturing particles of all sizes and shapes with equal and known, although not necessarily per- fect, efficiency. The samples should also be collected in such condition that identification, counting, and analysis would not be more difficult than with present samplers. Ob- viously, such a sampler would have wide application in sampling air pol- lutants of all types. Attempts to de- velop two samplers having these characteristics are in progress at Brookhaven National Laboratory but neither is yet operational. Further research and development on sam- pling methods are needed. Until improved samplers are de- veloped, rotating impactor samplers will remain the most quantitative method of sampling aeroallergens. Only one of these, the rotoslide, has been tested under controlled condi- tions for collecting efficiency for rag- weed pollen. Efficiency determina- tions for the rotoslide and the other rotating impactor samplers should be made for a wide range of pollen and spore types and sizes. More research is also needed to determine the best available adhesive for these samplers and to develop better methods of application. Since the efficiency of impaction samplers is a function of particle characteristics, these should be de- termined for at least the more com- mon aeroallergens. Most needed are measurements of pollen and spore density, but changes in size, density, and the state of conifer pollen blad- ders with age and humidity also need investigation. Studies are also needed to assess the temporal and spatial representa- tiveness of single-station samples as a function of surroundings (terrain, vegetation, and man-made structures), distance from sources, meteorological 348 AIRBORNE BIOLOli RIALS variables, and particle type. Such studies would permit estimation of the probable range of error caused by considering a sample representative of a wider region or a different time period. Peak-to-mean concentration ratios should be studied so that short- period concentrations can be esti- mated from longer-period means with some statistical reliability. Finally, the efficiency of the human nose as an aeroallergen sampler should be investigated to aid in relat- ing measurements of ambient con- centration to allergic symptoms. Some allergists believe it is more important to determine what is being inhaled than to determine accurately what is in the air. A sampler simulating the human breathing and retention mech- anisms should be worth developing. Further studies involving aeroaller- gen sampling that might be expected to result in advances in knowledge and methods include: 1. Studies of the relationships be- tween aeroallergen concentra- tions and pollinosis or other health effects. 2. Studies of the effect of weed- control programs on local con- centrations of an aeroallergen. Such studies should include adequate before-and-after sam- pling with appropriate sam- plers. Weed-control programs would not seem useful unless preliminary measurements of both locally produced pollen and that transported into the area from outside sources indi- cate that reduction of locally produced pollen would cause a medically significant decrease in over-all concentrations. 3. Studies of the production, re- lease, transport, dispersion, and removal of aeroallergens from known sources. 4. Studies designed to evaluate the efficiency of natural par- ticle-removal mechanisms such as washout by precipitation or impaction by vegetation (green- belts, shelterbelts, or forests). 5. Surveys of the incidence and concentration of aeroallergens as a function of time, meteoro- logical conditions, and other pertinent variables. Since individual allergists and their societies have shown a marked reluc- tance to adopt new and improved methods for sampling aeroallergens, public agencies should set an example by taking the lead in using and recommending the most appropriate of these devices. 349 PART X — ENVIRONMENTAL CONTAMINANTS 3. PESTS AND PESTICIDES Environmental Pollution and Pesticides The history of man is a history of his modifying his environment to suit his own needs and desires for food, shelter, and the pleasures of his own leisure. Primitive man lived as an integral part of the living and nonliving environment, but as his proficiency to further his own ends has advanced, he has progressively taken on a more dominant, displacive role. Because of his success and his awesome technology for modifying the world in achieving that success, man now faces the dilemma that if he proceeds as he has been he will de- stroy or greatly lessen the earth's capacity to sustain life, himself in- cluded. Shortcomings of Present Technology Among his technologies, some of which embody greater attacks on the biosphere, man has developed an "advanced" technology of pest con- trol. This technology can only buy time while we find a solution to the main problem of human population growth and establish a redirection of all our technologies along more compatible ecological lines. Pest-control technology, through use of modern synthetic chemical pesticides, achieved a high degree of perfection in terms of control of in- sect pests for a time. It was, however, developed single-mindedly with no real regard for ecological conse- quences. It was based on the stag- geringly false cliche that "the only good bug is a dead bug," and on the incomprehensible premise that each pest problem is a separate one — with no entangling feedback loops disturb- ing to crop-protection objectives. Thus, we have developed deadly, broad-spectrum, persistent pesticides and used them too indiscriminately and in ignorance of, and disregard for, ecological consequences of vital concern, often creating pest situa- tions worse than the original ones, to say nothing of ancillary problems of much importance. Among the adverse consequences of a single-objective pesticide tech- nology are: 1 . Resistance has developed in many target species. (See Fig- ure X-ll) The more rapid the resurgence, the more rapidly is resistance developed; and re- sistance to alternate materials then used often develops even faster. Most materials are nonselec- tive, directly affecting the nat- ural enemies of the target pest, often more so than the pest. Rapid resurgence of the pest species then occurs. Destruction of key natural en- emies can be indirect, through too severe destruction of the target pest itself (the enemies starve out) and through de- Figure X-11 —RESISTANCE OF INSECTS AND MITES TO PESTICIDES 1910 1920 1930 1940 1950 YEARS 1960 1970 1980 The graph shows that the number of resistant species has been increasing rapidly since the early 1950's and now stands at about 240. The changes in pest species that allow them to survive at higher and higher concentrations of insecticides are genetic and result from natural selection. Unfortunately, the graph tells the story only of known pests. Large numbers of insect species that have not been examined are subject to the same selection for resistance. When and if these insects erupt as agricultural pests, they will already possess a significant resistance to pesticides. 350 STIC1DES struction of some alternate prey species, perhaps of no economic importance. This can lead to resurgence. 4. Previously secondary pests or entirely innocuous species are commonly unleashed; this has usually been due to disturbing effects on their natural enemies. 5. Destruction of honey bees and other important pollinating in- sects. 6. Hazards to the applicators (many deaths and much sick- ness). 7. Hazard to crop culture on the same ground (overload of per- sistent pesticides in the soil, etc.). 8. Immediate hazards to man and wildlife that enter the treated areas. 9. Hazards to nontarget orga- nisms in places well removed from the treated area. This in- cludes significant influences on birds like pelicans, ospreys, and eagles that feed high on the food chains and especially on ones living around estuaries where DDT, for example, is concentrated; on important es- tuary anthropods; on grazing livestock and even man himself as a result of residues on crops or range or in fish, etc. DDT, for example, has moved widely in the biosphere — it is found in sea life at the antarctic. Drain- age of pesticides into lakes and rivers has caused great kills of fish and much public alarm. The herbicide 2,4, 5-T is appar- ently being withdrawn from the market for fear of adverse effects on man and livestock during pregnancy. An Enlightened Technology — Integrated Control An enlightened pest-control tech- nology is one that maximizes benefit/ cost relationships and minimizes en- vironmental degradation. The philos- ophy and methodology of integrated control aims to this end. The weather is a powerful mor- tality factor for many pest species, but we cannot manipulate the weather. Natural enemies of pest species are nature's own pest-control specialists, and their use causes neither outbreaks of innocuous spe- cies nor environmental degradation. Moreover, such species are quite manipulatable. Their great impor- tance in general is suggested in the very fact that secondary and formerly innocuous species are unleashed and become serious pests when disturbing pesticides are used. Why are only 2 of the 100 phytophagous species on cotton in California found to be se- rious pests? Why is our natural vegetation so seldom grossly de- voured by the myriad of phytopha- gous species that attack it? Many upsets have followed use of pesticides in these situations and adverse effects on natural enemies is considered the usual reason. Natural enemies should be explored in much greatt the enlightened new pest-control technology. In spite of the repercussions from unwise use of pesticides, pesticides nevertheless remain a most useful tool for managing our insect pests in a manner compatible with this objective. Use of selective pesticides, selectively used, offers our best op- portunity of making maximum use of natural enemies, combined with cultural methods, lures, and other schemes. The development of a new form of "biological" pesticide — i.e., hormones — offers new possibilities of selective pesticides. During the time we are learning to better use the resi- dential natural enemies and finding new and better ones for introduction, or perhaps altogether new means of pest control, pesticides will be espe- cially needed. (See Figure X-12) We do not now have adequate natural enemies for all the major pests on many crops (although this might prove to be more nearly attainable Figure X-12- -PESTICIDE USAGE AND AG RICULTUHAL YlhLU: 3 Pesticide Use Yield Area or Nation Grams per hectare Rank Kilograms per hectare Rank Japan 10,790 1 5,480 1 Europe 1,870 2 3,430 2 United States 1,490 3 2,600 3 Latin America 220 4 1,970 4 Oceania 198 5 1,570 5 India 149 6 820 7 Atrica 127 7 1,210 6 The table shows the close parallel between rank order of pesticide usage in selected countries and areas and rank order of agricultural yield. Note, however, that Japan produces twice as much food per hectare as the United States, but uses ten times the amount of pesticides. Similarly, the U.S. has over twice the African yield per hectare, but uses eleven times as much pesticide. The question is whether such a high ecological cost for food production is unavoidable or the result of a particular agricultural system. 351 PART X — ENVIRONMENTAL CONTAMINANTS than many think) and we need selec- tive use of pesticides to make the best use of the ones we have. In developing modern pesticide programs, we need to consider the following: 1. Complete control of the pest is not essential or even desir- able. Treatments can be re- duced in number and dosage if realistic economic-injury levels are established; natural en- emies are then left to dampen resurgence tendencies and the rise of secondary species, the resistance problem is not ag- gravated, and less toxic mate- rial is added to the environ- ment. 2. The faunal elements in the environment are interrelated. The biologies and roles of seemingly insignificant species may be a clue to effective use of a natural enemy against a major pest. Thus, in winter, a tydeid mite is a significant al- ternate for an important preda- tor of spider mites on grapes in the San Joaquin Valley in Cali- fornia; here, too, the non- economic leafhopper Dikrella cruentata found on wild black- berries is essential to the over- wintering of the effective para- site of the grape leafhopper, Erythroneura elegantida, a key pest of this crop. Planting of small patches of blackberries near extensive vineyards can thus provide the ingredient for control of the pest species on grapes, and the cessation of treatments for this leafhopper can result in the natural solu- tion of the spider-mite problem that the pesticides induce. 3. Using the pesticide at the dos- age and manner having the op- timal effect in providing imme- diate relief from damage but causing a minimal ecological disturbance may require a ma- terial having some persistence. Short-lived alternatives to some persistent materials may be even more objectionable, and more repeated applications may be required, thus magnifying the problems. 4. If effective and practicable pes- ticides should be used in spe- cific parts of the environment rather than as general coverage materials. 5. Each pesticide should be ap- praised separately and on the basis of specific use unless, as seems the case for DDT, the general severity of the pollutive accumulation in the environ- ment justifies its demise (aside from public health use in heavily malarial areas, etc.). 6. Natural enemies, cultural meas- ures, traps, and other feasible nonpollutive measures should take priority over use of pes- ticides, with the latter used to supplement them. Cultural measures may include growing of trap crops or ones harboring alternate hosts of enemies, de- struction of pest-harboring ref- uges, use of planting dates, etc. Releases of sterile insects or use of genetic techniques should be tried when promising for a particularly difficult species, where its solution would open up avenues for better-integrated control of the pest complex. Releases of the pest itself, use of strategic repetitive releases of natural enemies, augmenting techniques, and introductions of new natural enemies should be especially explored in depth. It is a fallacy to think that, since crops are highly artifi- cial (unnatural) and grown as simple monocultures, the laws governing the balance of nature and the role of natural enemies are insignificant here. Complex natural communities present a more stable picture than sim- pler communities because of the greater diversity in trophic links. Yet many of the species of natural enemies accounting for the low numbers of a po- tentially disturbing (to the community) phytophagous in- sect are highly host-specific. Such links (host and host- specific enemy) are often trans- ferred to crop situations. Some- times the pest form has arrived without the natural enemy. Our best examples of biological control have resulted from our seeking out and introducing such natural enemies. Integrated control, a systems- analysis approach, can be built on the basis given above. The computer is essential in systematizing informa- tion and testing hypotheses of how complex systems work so as to ar- rive at proper manipulating strate- gies, but it cannot substitute for grass-roots information. Much grass- roots input is needed before any major complex case (crop) can be put on a rational, predictable scheme of management. Key natural enemies commonly present a high degree of predictability for certain major pests (and others can be developed), thus making it possible to develop the sys- tem around such a central fact when established. Moreover, we must go on with the task of working out con- trols while we are gaining additional insights for a full systems-analysis approach. In-depth study of faunal relationships and crop phenology, economic-injury levels, and the like are musts. For an integrated control scheme to be fully effective in achieving the goal described, a revolution in the system of pest-control advisement is essential, and this cannot be accom- plished without massive training and re-training of a corps of pest-control ecologists (see below). Moreover, the whole social, eco- nomic, and cultural situation relative to insects or insect parts in foods, as 352 PESTS AN ' !DES well as the "cosmetic" pests and others, needs changing. Unrealistic marketing standards, consumer at- titudes, government regulations, and so forth perpetuate an unrealistic demand for totally unblemished, in- sect-free produce; this demand can greatly complicate an otherwise real- istic solution which could provide high-quality produce and high yields at reasonable cost. The Status of Our Knowledge The final result of the approach described above should be an en- lightened systems-analysis approach to decisions on strategy and tactics of pest control, with due allowances (based on value judgments that so- ciety will have to make) for the im- pact each measure might have, not only for the benefit/cost relationship (to the grower and the consumer), but for the quality of the environ- ment (health, wildlife, aesthetic, etc.). Research Needs — We need mod- els for depicting the control of a com- plex of pests on a crop. The modeling of a single pest population in the field has progressed rather far in a few instances. There is, for example, a model of a laboratory population of a grain insect and its parasite over 23 generations, with remarkably good prediction for the whole 23 genera- tions — not just generation by genera- tion. However, this is a simple two- species system in a simple, constant environment. In the field, we need to gain similar insights into the whole environmental complex (biotic and abiotic), especially the natural-enemy performances relative to the climatic regime, the key pest species, and the possible influences of given pesticides on them (and on ones keeping the innocuous species under control). We also need better knowledge of the phenology of the crop and cropping practices relative to the pests. We have only the roughest information on the economic- injury levels for any pest. Of the few we have studied, the numbers of insects required to cause economic injury are much greater than previously considered. This is prerequisite to using pesti- cides wisely or in not using them and relying more on natural controls or cultural measures. We need much greater emphasis on means of augmenting the value of natural enemies. Only a beginning has been made relative to use of strategic releases of both pest and enemy species, adding supplemental foods or alternate hosts for enemies in the environment (or nesting sites for avian predators of insects), or using special strains or genotypes of a natural enemy species. The intro- duction of new natural enemies is a vast, largely untapped resource. The hesitancy in doing so, based on theoretical considerations, is refuted by the record of over seventy years; moreover, new theory confirms past policy and speaks for much wider use of new introductions. The main reason why more biolog- ical control has not been accom- plished is that vastly too large a por- tion of available effort has gone into work on pesticides in the area of single-minded pesticide-use technol- ogy. A disproportionate amount has also gone into the development of new ideas (e.g., use of releases of sterile insects) that have succeeded only to a very limited degree and and do not offer prospects for wide- scale commercial solutions. A record of some 70 cases of complete biologi- cal control and 250 with at least par- tial success for the world is a for- midable achievement in the light of the effort that has been made on biological control. Economic and Political Considera- tions— The pesticides that have been developed are broad-spectrum ones, which is natural since the industry has been motivated by profit. Only token consideration has been given to other aspects (but more so relative to human health). What is needed are pesti- cides with selective activity — i.e., which act on a group of pe with little effect on key natural i groups. It is said to cost from t million to $15 million to develop a pesticide and market it. Many more pesticides would be required for the new technology, and sales of each would be limited. The market price would be high. The public must de- cide if it wants the less pollutive tech- nology badly enough to pay the price in some form of subsidy to develop these materials. Actually, such mate- rials could be nearly self-supporting, since the grower could afford a higher price for them if his total usage of pesticides is thereby greatly reduced. Use of resistant hosts has been use- ful in many instances and will be again, but superimposing a pest-re- sistance requirement on top of the already staggering problems in devel- oping high-yielding, good quality, marketable cultigens means that this solution is not likely to be a general one. Training Advisers — Lastly, we need to change our whole system of pest-control advisement. In the past it has been based to a large extent on profit from sales. The ecologically un- trained, or even the ecologically an- tagonistic, have often been used as salesmen. There has been great pres- sure on them to sell. They are the closest "advisers" to the growers, who in many cases have relied on them heavily. Excessive concentration on sales and too little attention to need and consequences has led to the cur- rent situation. What is needed is a corps of well- trained professionals who sell their advice — i.e., advice not to treat as well as to treat — but not the pesticide itself. Thus, the system of advising should be separated from profit from sales. Since pesticides constitute a poisonous factor in our environment, reaching beyond the confines of the area treated, it seems necessary that society set up such a safeguard, as it has long since in the dispensing of 353 PART X — ENVIRONMENTAL CONTAMINANTS drugs for medicinal purposes. Whole new programs of training pest-control professionals who will do this advis- ing are needed in the universities. A General Perspective — It will be necessary that adequate care is taken to assure that the necessary changes in philosophy and methodology are made at each institutional level. The old philosophy and methodology have been entrenched for 40 years, and nothing less than extreme action will alter the picture fast enough. At the same time, it is wishful thinking to pin hopes on conceptually intriguing new, but generally un- proved, ideas of pest control — e.g., use of sterile insect releases, inunda- tive parasite releases, genetic tech- niques, hormones, special wave- lengths, plastic exclusion airdomes, and the like. A planned systems- analysis integration of the long- established techniques of biological and cultural controls, and limited but strategic use of selective chemical controls, offers our best prospect of solutions on a broad scale. Pesticides and the Pollution Problem In a broad and complete view of pollution of the earth's biosphere, pesticides are a minor element. Never- theless, for certain local environments or for certain endangered species, the pollution from specific pesticides has become a problem worthy of special attention. In our general concern about this pollution and in our re- sponse to other undesirable effects of certain pesticides, it is not rational to condemn all pesticides. Further- more, it is ill-advised to attempt to ban all pesticides (even all persistent pesticides) in the misguided hope that this will protect birds and other wild- life from the effect of man's disrup- tion and pollution of the environment. Even if all pesticide use were stopped, other activities of man would cause broad and sweeping disruptions of his ecosystems and threaten many forms of desirable life on this planet. Uses and Limitations of Pesticides Pesticides remain, in spite of ad- verse publicity, man's most powerful tool in the management and control of pests. We have no choice, if we insist on even minimal food, health, and comfort, but to control pests. The pesticides developed in the past 25 years are effective and economical and can be marshalled quickly to have immediate impact on a pest population — even over a large area. When pest populations approach eco- nomic levels, there is little other than pesticides that we can use to avoid damage and which will have the de- sired immediate effect. Hence, it seems clear that pesticides must and will continue to be used in a major way in pest management. The disadvantages or limitations of pesticide chemicals are well known. They have been so emphasized in the press, on radio and TV, in politi- cal arenas, and elsewhere that it is now difficult to have a rational dis- cussion that balances the beneficial and the undesirable aspects of pesti- cides. In brief review, the limitations of pesticide usage are as follows: 1. Selection of pest strains that are not controlled by usual pesticide dosages. 2. Temporary effects on pest pop- ulations necessitating repeated treatment (often the pest popu- lation quickly returns to a higher level than before treat- ment). 3. Hazards from residues of the pesticide in the harvested crop. 4. Outbreaks of secondary pests unleashed by destruction of their natural enemies. 5. Undesirable effects on nontar- get organisms, including (a) parasites and predators; (b) fish, birds, and other wildlife; (c) honey bees and other nec- essary pollinators; (d) man and his domestic animals; and (e) the crop plant. o. Direct hazards to man during the application of pesticides and subsequently in the treated area. 7. Reduction and simplification of the biotic component of the agro-ecosystem. Factors Affecting Pesticide Use This formidable list makes it nec- essary to re-evaluate carefully the appropriate use of pesticides. It also serves as a basic guide to the im- proved use of pesticides for pest management and control. If we can devise procedures for the use of pesticides which will avoid or mini- mize these disadvantages or com- plications, then we will have devel- oped an improved, perhaps even an ideal, methodology for the efficient and effective use of pesticides. Destruction of Natural Enemies — Ecologists concerned with the control of pest insects have for some time been alarmed at ecological disturb- ances in agro-ecosystems engendered by the unwise use of pesticides. These are caused by the unintended destruction of natural enemies, which in turn results in rapid resurgence of the target pest species or a sec- ondary outbreak of an unleashed but formerly innocuous insect. For ex- 354 PESTS AND PESTICIDES ample, where a broad-spectrum pes- ticide is used (and natural enemies of the pest are also eliminated) or when high dosages of a selective ma- terial are used that kill off high per- centages of the pest (and thus starve out the natural enemies by eliminat- ing their food), the pest populations can recover quickly without hin- drance of natural enemies. This destruction of natural ene- mies, as an unfortunate side effect of pesticide usage, has two main consequences. First, the target pest may quickly recover from the impact of pesticide usage and resurge to even higher levels. (See Figure X-13) Sec- ond, the resurgence of unleashed secondary pests may occur shortly after the application of the triggering pesticide, or later in the growing sea- son, or even in a subsequent season. In cotton in California, for example, we have had serious outbreaks of such unleashed secondary pests as beet armyworm, cotton-leaf perfora- tor, and cabbage looper. These sec- ondary pests may be more destructive and more difficult to control than the original target pest. Re-establishing the effectiveness of natural enemies may require two or more years. Health Hazards — It is obvious that we should not knowingly use pesti- cides in ways that would constitute a risk to human health. Such hazards can occur to the individual applying the pesticide, or to persons entering the treated area either during the application or at some appreciable time later, or to persons exposed to the residues of the pesticide on or in the harvested crops, or in other more subtle ways. When such a hazard is discovered, procedures should be taken to avoid the risk — Figure X-13 — RESURGENCE OF CALIFORNIA RED SCALE Population Density- -California red scale Orchard No. Locality li nitial Final DDT- treated Un- treated DDT- Un- treated treated 1 Irvine, Orange Co. 0 2 125 3 2 Sinaloa, Ventura Co. 35* 46* 572 17 3 Sespe, Ventura Co. 1 1 425 7 4 Biological Control Grove UCR, Riverside Co. 8 2 246 8 5 Birdsall, San Bernardino Co. 0 0 67 6 6 Beemer, San Diego Co. 4 5 158 3 •Initially heavy, due to previous upset by ants. Ants were controlled subsequently. The table shows differences in the density of California red scale between trees left under normal biological control and some experimental citrus groves treated with DDT. The initial counts, comparable in both sets, were made just before DDT was applied; the low ratings (mostly 10 or less) indicate that the scale was scarce and under an excellent degree of natural control. After one or two seasons of treatment with DDT, however, red scale was far more common, whereas the scale on the untreated trees was evidently held in check by natural enemy activity. Ratings above 50 to 100 begin to cause visible, and economically unacceptable, twig and branch kill. e.g., proper masks and clothing for applicators, minimum time period af- ter treatment before the treated area can be entered, or minimum time after treatment before harvest. In those instances where the risk can- not be avoided, then use of that particular pesticide should be cur- tailed and a suitable alternative con- trol measure sought. This is not to suggest that all uses of the pesticide be banned but rather that the par- ticular hazardous uses be eliminated. Furthermore, when alternatives are considered, all aspects, both positive and negative, should be carefully weighed. Limitations of Substitute Mate- rials — In the past year or more, there has been considerable public pressure to eliminate all persistent pesticides. Let us not forget that, if this comes about, society is losing valuable tools for pest control and that there are other problems associated with many of the substitute materials. Basically, each compound should be considered individually as to its peculiar risks on the basis of its specific characteristics together with the exact manner of dosage and place of application. To date, the substitutes have usu- ally been either organophosphorus compounds or carbamates, though it is difficult to generalize because there are so many exceptions. The sub- stitute materials used so far have shown, first, a frequent pattern of higher acute toxicity, with associated greater immediate risk to man, live- stock, and wildlife. Secondly, these substitute compounds frequently have produced serious damage to honey bees and other necessary pollinators; their impact on the California bee- keeping industry has been disastrous. Thirdly, they have had a severe im- pact on insect natural enemies. As noted above, elimination of natural enemies from treated areas frequently permits rapid resurgence of the target pests and outbreaks of previously in- nocuous species. Finally, the short- lived nature of the substitute mate- rials together with their side effect 355 PART X — ENVIRONMENTAL CONTAMINANTS on natural enemies requires repetition of applications. This increases the selection pressure for resistance in some cases and hastens the develop- ment of populations resistant to the chemical. Persistence of a pesticide chemical is not in itself an undesirable quality. Normally, we need some level of per- sistence for pest control. This is es- pecially true when the pest popula- tion moves slowly into a susceptible stage of development or out of hiber- nation quarters or other inaccessible or unbeatable habitats into the area of contact with the pesticide. If the movement into the area to be pro- tected extends over an appreciable length of time, the pesticide must persist over this length of time or else repeated treatments with a non- persistent material will be necessary. In general, the latter procedure will be more costly and more hazardous. Persistence is a disadvantage when it is the cause of undesirable residues on the harvested crop or elsewhere in the agro-ecosystem, or when the pesticide is concentrated through food chains to harmful levels in non-target organisms. (See Figure X-14) Again we must strike a balance between costs of alternative procedures and between the benefits and undesirable effects of these procedures. This com- parison should not be made only in narrow economic terms but also with full consideration of the social costs and benefits. Guidelines for Good Pest Management Today many decisions with respect to pest control are being made in a political context and with little con- sideration of the fundamental tech- nological facts upon which sound pest-control decisions should be based. Each pesticide usage should be judged on the basis of the poten- Figure X-14 — CONCENTRATION OF DDT IN A LAKE MICHIGAN FOOD CHAIN DDTinppm Water 0.000002 Bottom mud 0.014 Fairy shrimp 0.410 Coho salmon, lake trout 3-6 Herring gull 99 The table shows why minute quan- tities of DDT in lake water are a serious problem. The rate of ac- cumulation is proportional to the concentration of DDT in the water multiplied by the time of exposure. By the time DDT reaches fish, its level of concentration can cause reproductive failure. These con- centrations in the fish in turn be- come a hazard to the piscivorous birds at the top of the food chain. Retention time for DDT in water averages 30.8 years. No solution to the problem is yet evident. tial positive values to be achieved by such usage as weighed against the possible negative values occurring from residues on the harvested crop, occupational hazards to humans, haz- ards to pollinating and other benefi- cial insects, effects on wildlife, the contribution to total environmental pollution, and other direct or subtle effects. Each use of a chemical must be judged independently. Banning all uses of a chemical is unwise unless it is clear that all uses of that chemi- cal are harmful. Likewise, it is ir- responsible to advocate the total replacement of pesticides with so- phisticated but poorly tested alterna- tive pest-control techniques. It is a disservice to society to discard the good crop-protection methodology currently available and to adopt in its place a glamorous new but untested methodology. In the future develop- ment of crop protection for a world agriculture, it will be just as impor- tant to apply the methodology of traditional pest-control techniques as it will be to find revolutionary new approaches, some of which may be expected to have little or no practical value. Research — In the interest of a bet- ter environment, the integrated con- trol concept must be fostered among pest-control researchers, and research on pest-management systems should expand as rapidly as possible. There is a critical need for information on many aspects of integrated control, including pest economic thresholds, natural control, ecology, phenology, and the nature of agro-ecosystems. Such studies will provide informa- tion permitting better timing and placement of insecticidal treatments and will lead to the development of alternative control measures. Studies of this sort are currently being sup- ported by federal and state agencies and some of the commodity groups, but the need exists for greatly ex- panded support. Manpower Training — The more sophisticated controls and integrated control systems will create a demand for more highly qualified people in pest control. Consequently, there is an urgent need to develop, simultane- ously, training programs for ecologi- cally oriented pest-control advisers. Practicing economic entomologists versed in the principles of integrated control are extremely rare today and badly needed for an ecological ap- proach to pest control. The training of a new corps of researchers and advisers well versed in integrated control will entail careful planning and the development of a new type of curriculum. 356 4. MARINE CONTAMINANTS Effects on the Ocean of Atmospheric Circulation of Gases and Particulate Matter The transport of materials from the continents to the marine environ- ment takes place primarily through wind, river, or glacial systems. The activities of man have added two other paths: (a) introduction, both by intent and by accident, from ships and domestic and industrial sewage outfalls, and (b) introduction by man of materials to the atmosphere, with subsequent impact upon the oceans. The latter path will be emphasized here. Aerial transport can result in the rapid and widespread dispersal of solids, liquids, and gases. For ex- ample, radioactive debris in the troposphere from the Chinese nuclear device tested in 1965 fell back to earth in a latitudinal band following its transport in the jet streams; these materials circled the world twice with an average velocity of 16 meters per second. The ocean acts as a reservoir for the dissolved phases introduced to it and maintains them for periods of the order of centuries to thousands of millenia. Thus, the impacts of man upon the seas, if measurable today, will also be measurable many, many generations into the future. There are probably three major re- sponses by the environment to such impingements by man: alteration of its physical nature, alteration of cli- mate, and alteration in the constitu- tion of communities of organisms. Although some of the changes are quite difficult to detect today, none- theless, on the basis of our knowl- edge of the types and amounts of materials being dispersed to the air, there is hope for some predictions. Impact of Man-Made Materials Managing the discharge of mate- rials to the atmosphere will take on greater importance with time as both population and the material and en- ergy utilizations per capita increase in the world. We have successfully managed, so far, the releases of radioactivity to the environment from nuclear reactors. On the other hand, we have had serious problems with the disposition of pesticides to our surroundings; clear-cut impacts on the communities of birds have been felt. The definition of critical prob- lems in atmospheric release of solids and gases such that appropriate ac- tions can be taken by policymaking bodies is clearly the end-point of the considerations presented here. Metals — The identification of the materials from fuel combustion and from industrial production is incom- plete, especially with regard to the latter category. Metals such as mer- cury and arsenic, which have volatile forms, are entering the atmosphere — and subsequently the oceans — as a result of mining and extractive metal- lurgical, industrial, and agricultural operations. High concentrations of atmospheric mercury accompany the smog in the San Francisco Bay region. High arsenic contents of Japanese rain waters have been attributed to the smelting of sulfide ores and fuel combustion. The flow of such sub- stances through our surroundings is poorly defined. About 2.5 percent of the total production of gasoline is lost by evaporation during trans- fer processes, from production site to vehicles and to storage tanks and through vaporization from the auto- mobile gas tank and carburetor. This amounts to several million tons per year throughout the world. Again, the subsequent activities of this gas- oline in the air are as yet undeter- mined. Chemicals — Volatile synthetic or- ganic chemicals are dispersed about the atmosphere and their impacts are still described inadequately. The losses of dry-cleaning fluids and freon, though not necessarily the most important emissions, are none- theless illustrative of the types of material flows that should be studied. The evaporation of dry-cleaning sol- vents must be of the same order of magnitude as their production — sev- eral hundred thousand tons per year. The most widely used substance is perchloroethylene. A similar amount of dichloro- difluoro-methane (Freon-12) enters the air following its use as a propel- lant in the bombs containing shaving cream, deodorants, paints, and so on. Do such materials retain their iden- tity before entering the oceans or are they degraded as atmospheric gases? The gas chromatograms of liquid air condensates from the at- mosphere contain many unidentified peaks, perhaps volatile synthetic or- ganic compounds. A systematic in- vestigation of possible inputs, based on production figures and field ob- servations, would be most rewarding. Fuels — The greatest single source of man-introduced materials to the environment encompasses the prod- ucts resulting from combustion of the fossil fuels — coal, oil, and natural gas. Since 1850, the amounts burned have doubled about every fifteen to twenty years. Carbon dioxide is the principal gas released in such proc- esses; its rate of increase at the pres- 357 PART X — ENVIRONMENTAL CONTAMINANTS ent time is 0.8 parts per million per year for an atmosphere containing about 320 parts per million. About 40 percent of the carbon dioxide so introduced still remains in the atmos- phere. The main sink for this added carbon dioxide has not yet been es- tablished, although it is most prob- ably the deep ocean. There have been suggestions that land plants, through more extensive growth, have accommodated this additional carbon dioxide. Whether such introductions have increased plant productivity in the sea through the input of addi- tional carbon dioxide to the surface waters and whether the earth's tem- perature has increased through the "greenhouse effect" created by this excess carbon dioxide are questions not yet resolved. The search for the sinks of the products of fossil-fuel combustion has widened our knowledge of nat- ural phenomena. For example, at one time it was thought that the fate of carbon monoxide, resulting from the incomplete combustion of fossil fuels, was either an atmospheric oxidation or an uptake by seawater. Surface seawaters have carbon mon- oxide concentrations ten to forty times higher than atmospheric equi- librium values and the marine en- vironment turns out to be a source for carbon monoxide. Mid-tropo- spheric concentrations in the sub- tropics display no marked differences between the two hemispheres, indi- cating that the source of the carbon monoxide is natural and that the atmospheric lifetime of the gas is of the order of a year or longer. Higher values of carbon monoxide have been found in the air over open ocean waters as compared to the air over bay and river waters. Preliminary calculations of the oceanic output give a value of the order of ten million tons per year, about five percent of the 200 million tons annually generated by the burn- ings of fossil fuel. The sources of the carbon monoxide in the oceans are probably biological — through the bacterial or photochemical oxidation of organic matters in surface waters or through the direct production by marine algae, "Portuguese Men of War," or siphonophores. The disposition of the carbon monoxide in the atmosphere is not yet known. The principal sink will probably turn out to be stratospheric oxidation by OH, H-O.., or HO- radi- cals. Another possible fate of the carbon monoxide may be an oxidation to carbon dioxide by soil bacteria. Insights into Natural Processes The researches with carbon mon- oxide illustrate a common result of environmental studies — we learn about natural processes through in- vestigations of pollutants. Such was the case with the radioactive species introduced through the detonation of nuclear devices both in the atmos- phere and in the oceans; our knowl- edge of mixing processes within these two geospheres was decidedly en- hanced. In addition, marine eco- logical research has been sponsored primarily by atomic-energy agencies that are concerned about the inter- actions of radioactive species pro- duced by fusion and fission reactions with members of the biosphere. Complementarily, guidance as to the fates of man-introduced materials to the atmosphere-ocean system can come from knowledge about the nat- ural substances involved in the major sedimentary cycle. Atmospheric Transport — Over the past decade, the transport of solids to the marine environment by at- mospheric paths has become a most attractive area of research. More than a century ago, Darwin had suggested that major expanses of sediment on the open ocean sea floor are the result of an atmospheric transport from continental arid regions. Yet only recently have we been able to state with some confidence that most sedi- mentary solids in the North Pacific, North Atlantic, and Arabian Sea are derived from the continents by wind transport. Perhaps more important is the observation that the geographic distribution patterns of diagnostic minerals in the deposits moderately well define the bounds of the wind systems. For example, in the North Pacific the concentration gradients of the clay mineral illite and of quartz in the sediments closely parallel the gradients in the intensity of the jet stream averaged over a year. Simi- larly, off the west coast of Australia, the prevailing southeasterly winds are recorded in the sediments by high concentrations of the clay mineral kaolinite that they carried from the Tertiary laterite deposits on land. Atmospheric Dust — Removal of solids from the atmosphere takes place through scavenging by precipi- tation, rain, snow, sleet, and rime and by gravitational settling, with the former process being the more im- portant. Since the average time be- tween rains in many parts of the world is counted in weeks, transport of suspended particles can take place over great distances. Dust collected on the island of Barbados originated in the European-African continents with a transport by the northeast trade winds. Such materials were also picked up further along their transport path in the glaciers of Mexico. The industrial activities of civiliza- tion are recorded in such dusts. Many atmospheric solid samples collected in the Atlantic are gray to dark gray in color due to pollution by carbon and fly-ash spherules. Increases in the rate of dust accumulated in the Caucasus glaciers have been related to the mechanization and indus- trialization of eastern Europe. The dust accumulation rate clearly shows marked increases beginning in 1950, which parallels the growth in the Soviet economy. (See Figure X-15) Possibly, a more pertinent case for the impact of man upon the marine 358 MARINL CONTAMINANTS Figure X-15 — COMPARISON OF CAUCASIAN DUST FALL AND THE SOVIET ECONOMY 240 160 E 80 DUST FALL IN CAUCASUS AMOUNT IN CAPITAL STOCK III 250 1930 1940 1950 1960 The diagram shows a close correspondence between (a) measurements of fallout of atmospheric dust in milligram per liter, as measured in glaciers of the Caucasus mountains, and (b) the amount of capital stock (equivalent inventories, building and livestock) in the Soviet economy expressed in billions of 1937 rubles. environment may be seen in the find- ing of talc as a common constituent of atmospheric dusts. This mineral is rare in land soils, but appeared ubiquitous in solids collected from air masses, as well as in glacial snows deposited before 1946. This talc arises from its use as a carrier and diluent for pesticides in surface and aerial spraying of agricultural crops. Direct measurements of chlorinated hydrocarbon pesticides and their resi- dues have followed the discovery of talc in these domains. Comparisons of the contributions of river-borne and atmospherically transported pes- ticides to the marine environment have been made and both appear to be of the same order of magnitude. The atmospheric estimates based on particle collection are clearly under- estimates, inasmuch as some of the pesticides are carried to the marine environment in the vapor phase. Nonetheless, these mechanisms for conveying pesticides to areas of the oceans where river influxes appear to be slight do explain the increasing levels of chlorinated hydrocarbons appearing in birds and fish. Interactions of Contaminants and the Atmosphere-Ocean System The interactions of airborne con- taminants with the marine biosphere are more speculated upon than estab- lished. The scientific literature is re- plete with tales of woe concerning the possible effects of pesticides on the photosynthetic activities of marine algae and a consequential loss of oxy- gen from our atmosphere. Recent investigations do indicate that photo- synthesis and growth of some species of marine phytoplankton can be ad- versely affected by exposure to chlori- nated hydrocarbons; others show a complete insensitivity. But to ex- trapolate such findings to a possible elimination of all photosynthetic ac- tivity in the oceans appears un- warranted, inasmuch as the factors governing the gross production of organic matter in marine plants are still incompletely determined. On the other hand, present-day experimental and monitoring data do suggest that there is a significant decrease in the productivity of estua- rine fish and shellfish as a result of the ingestion of DDT and its residues, some of which is airborne from the continents. Further, it appears that the resistant surviving animals are able to concentrate and transmit toxic quantities of these residues in the food chain. The reproductive suc- cesses of seabirds has decreased due to interferences with their normal cal- cium metabolism by the high body burdens of these halogenated hydro- carbons. These birds, feeding on marine fish, are at the upper levels in the food chain. The marine fish are building up levels of these pesticides that equal, and sometimes exceed, those of their freshwater counter- parts. The ocean waters act as a reservoir for these river- and wind- transported materials, while the re- birth of rivers every year often results in lower concentrations even though the rivers are closer to their points of origin. These studies with DDT and its residues are providing a most impor- tant pattern to study the polycholori- nated biphenyls (PCBs) — another industrial chemical group, most prob- ably dispersed through the atmos- phere, that is appearing in marine fish and birds. Manufactured since 1929, PCBs are used as plasticizers, transformer fillings, solvents for 359 PART X — ENVIRONMENTAL CONTAMINANTS paint, and components of caulking materials. They probably behave similarly to the halogenated hydro- carbons in organisms, and there is great concern over their buildup in the marine environment. (See Figure X-16) Such materials will receive a good deal of attention in the coming years. But of greater importance will be the identification of other chemi- cals that are building up in organisms of the sea and that are capable of altering their life processes. Deleterious effects due to the entry of man's artifacts to the atmosphere- ocean system have been documented in only a few cases, such as those of pesticide residues on the reproductive success of some marine birds. We can expect other catastrophic episodes in the future, however. To react rationally and effectively to such events and to minimize their recur- rences, it will be important to have a past record of man's inputs to his environment, especially of substances that we do not now monitor for one reason or another. Use of Glaciers in Atmospheric Monitoring The idea of utilizing permanent snowfields (glaciers) to provide such information is not new. Yet researches on the glacial records of man's activi- ties at the earth's surface have so far been small and limited, even though permanent snowfields exist below all of the major wind systems and main- tain sequential records of atmospheric fallout for centuries and even for mil- lenia. Work on lead concentrations in ice layers from northern Greenland and from the interior of Antarctica have shown increases beginning at 800 b.c. to the present, with the sharpest rise occurring after 1940. These increases are ascribed mainly to lead smelteries before 1940 and to burned lead tetra-ethyl and lead tetra-methyl in internal combustion engines after 1940. In both cases, lead was introduced to the atmos- phere and brought back to the surface of the earth primarily in precipitation. The surface sea waters today show much higher lead concentrations than their deeper counterparts, an effect that diminishes as the open ocean is is approached. Predictions as to the future lead concentrations in the ocean can be made on the basis of extrapolated industrial activity and of models of the oceanic mixing proc- esses. Very important is our knowl- edge of the wind transport of lead aerosols in the past through our read- ing of the glacial record. The concept that the amounts of pesticides contributed to the tropical Atlantic by the trade winds are com- parable to those carried to the sea by major river systems was triggered by analyses of both pesticides and their carrier talc in permanent snowfield records as well as in direct analyses of river and atmospheric samples. Finally, the glaciers have recorded the inputs of sulfur dioxide to the atmosphere through the burning of fossil fuels. The excess sulfur in the atmosphere is now at least several times natural levels. Examples such as these point out one most important direction to go for obtaining benchmark data to study man's relationship to the chemistry of the surface of the earth. Figure X-16 — PCB RESIDUE IN FISH, BIRDS. AND MAMMALS Type Organ Location Concentration (ppm) Herring Fat Baltic 0.5-23 Salmon Eggs Sweden 7.7-34 Pike Muscle Sweden 6.0-48 Eider duck Liver Holland 2.1-96 Heron Liver Britain 0-900 Heron Fat Stockholm 9,400 Dolphin Fat Sargasso 33 Seal Fat Baltic 16-44 The table shows the ranges of concentration in parts per million that have been measure in various organs of several species of fish (cf., Figure X-14 for DDT). PCB's are not destroyed by usual waste-disposal methods. They enter the aquatic environment through sewage effluents, land runoff from industrial wastes, and condensation following incineration. PCB's have properties similar to DDT, but they are more persistent and stable. 360 Oil on the Sea Floor IVIAKilNL l^WIN 1 A1V111NA1N I 3 Recent observations concerning the fate of oil in the ocean after spills and leaks such as those in the Santa Bar- bara channel and from the S.S. Torrey Canyon off the English coast have led some investigators to conclude that dispersal methods that involve re- moving the oil from the surface by overpowering its natural buoyancy (thus transferring it to the sea bot- tom) are potentially more harmful to the environment than methods that leave the oil dispersed but floating on the ocean surface. Since sinking methods involve the use of extremely cheap agents (sand, ashes, and the like) and since they generally remove the oil before it can contact beaches, yacht hulls, and other recreational surfaces, there are strong economic and aesthetic argu- ments in favor of their continued use. On the other hand, if it could be shown that the transferral of toxic petroleum constituents to the sea floor would result in damage to demersal fisheries, there are strong arguments for establishing an effective interna- tional regime to control both drilling for and seaborne transportation of petroleum, wherever the possibility exists that it may be deposited in quantity upon the sea surface, and to fix responsibility, assess damages, and compensate those economically in- jured in case such an event occurs. Status of Scientific Knowledge Current scientific knowledge rele- vant to the problem of petroleum on the sea surface and sea floor is far from adequate with respect to reliable predictions of the possible harmful effects of removing petroleum or petroleum residues from the sea sur- face by sinking them to the sea floor. Amounts of Hydrocarbons in Marine Sediments — We do know already, from extensive investigations of the chemical composition of ocean sediments in many parts of the world, that detectable quantities of paraffins, aromatics, and asphalts — chemically indistinguishable from petroleum fractions — are present in ocean sedi- ments. (See Figure X-17) Ironically, these investigations have been carried out primarily to determine the sources of oil in sediments, not the fate of oil in the sea. Emery summarized much of this work in 1960 in his book The Sea Off Southern California. He found the greatest rate of accumulation of hydrocarbons in marine sediments to be in certain stagnant basins, where they could amount to as much as 0.15 percent of the dry weight of sedi- ment. Emery's calculations showed that about 880 tons of such material were deposited annually in the sedi- ments over an area of 78,000 square kilometers, compared to an annual production of 135,000 tons of similar materials by the phytoplankton over the same area. Disregarded entirely in this computation is the possibility that any of the hydrocarbon mal currently being deposited in the sedi- ments is reworked from the numer- ous seeps in this region of the Cali- fornia coast. Recent work by Horn, Teal, and Backus of Woods Hole Oceanographic Institution not only shows that float- ing lumps of petroleum residue are common on the sea surface but sug- gests two methods by which the con- stituents of such lumps can be trans- ferred to the sea floor through natural processes as well as a natural method for disposing of the material at the sea surface. Natural Sinking Processes — Goose-neck barnacles, which at cer- tain seasons of the year attach them- selves to any suitable firm substrate near the sea surface, were found adhering to floating lumps of petro- leum. Since these creatures secrete a calcareous exoskeleton, they are sig- nificantly heavier than sea water; Figure X-17 — PETROLEUM HYDROCARBON CONTAMINATION IN THE MARINE ENVIRONMENT SEDIMENTS Location ppm West Falmouth, Mass., USA ._._ - ..up to 12,400 (dry wt.) West Falmouth, Mass., USA 21-3,000 (wet wt.) Narragansett Bay, Rhode Island, USA - - 50-3,560 (dry wt.) Chedabucto Bay, Canada _~ 0-6.8 (dry wt.) The table shows some measurements of petroleum hydrocarbons found in sediments of coastal waters. Studies have shown that marine organisms are adversely affected by petroleum and that complex mixtures of petroleum hydrocarbons are present both in sediments and marine organisms. It is estimated that the input to U.S. coastal waters of petroleum hydrocarbon via sewage effluents ranges from 12,000 to 150,000 metric tons per year. 361 PART X — ENVIRONMENTAL CONTAMINANTS thus, as they grow they unquestion- ably transfer lumps of petroleum residue to the sea floor by adding weight. It is in all probability this effect and not slight toxicity that accounts for the observation that the largest barnacles attached to oil lumps were 8 millimeters long, whereas bar- nacles attached to pumice reached 11 millimeters. The existence of floating pumice itself suggests another possibility in the transfer of floating oil to the sea bottom. Floating pieces of pumice on the sea surface are observed to de- crease continually in size as the result of abrasion through wave action. The abraded particles in turn conceivably can be accumulated by (or accumu- late) petroleum particles to the extent that the mixture is heavier than sea water and hence sinks to the bottom. Surface Removal Through Bacterial Action — The mechanism for removal at the surface is bacterial oxidation. Horn and his colleagues found oxy- gen consumption of a floating oil lump at 10 centigrade to be about the equivalent of oxidation of 7 x 10 ° g/hr"Vcm"L' of petroleum. Since a sphere has a surface: volume relation- ship of 3/r, this observation tells us that floating oil with a density of 1.0, if divided into spherical particles of radius 21 x 10 ,; cm, will be com- pletely consumed in one hour at 10° centigrade. One can reasonably ex- pect this value to increase to 42 x 10"° cm at about 18° and to double again at about 26 centigrade. By the same arithmetic, a film of oil 7 x 10"'' centi- meters thick will be consumed in an hour if the bacteria thrive only on one surface at 10° centigrade, but in half this time if they can attack both surfaces at once. It may be more illuminating to consider these rates in terms of years (8,765 hours). At 10° centigrade, a layer of oil attacked on only one sur- face will be consumed at the rate of 0.6 millimeters per year. This figure may be compared with Emery's 880 tons per 78,000 square kilometers in a year, which is about 1.1 to 10"'' millimeters per year, or his 135,000 tons per year of petroleum-like sub- stances produced by phytoplankton, which is 1.7 to 10"'' millimeters. These rate computations allow us to draw several conclusions. One is that the practice of adding emulsi- fiers to floating oil to facilitate its dispersal into small units will also facilitate its natural oxidation as long as the emulsifiers are not bactericidal. Another is that keeping the oil at the sea surface, where ambient tempera- tures are highest, will minimize the time required for its natural oxida- tion. And another is that oil will be more persistent in polar latitudes than in temperate or tropical latitudes. Still another is that both "natural" accumulations of petroleum compo- nents in marine sediments and pro- duction of similar compounds by phytoplankton take place at rates much below the "natural" ability of the systems at the sea surface to oxidize floating oil residues. Inasmuch as bacteria form an im- portant food source for the ciliary and mucus feeders in the marine plank- ton, then, and since observation shows that bacterial growth is en- hanced in the presence of the combi- nation of solid surface and source of fixed carbon offered by floating oil lumps, it seems inconsistent to refer to their presence as "chronic pollution." Additional Sinking Agents — In shallow coastal water, supposing that oil is delivered to the sea surface at a rate greater than that at which it can be naturally oxidized, it seems likely that airborne dust and other solid residues will act as additional agents in increasing the density of floating oil and causing it to sink to the bottom. A layer of tarry residue will then exist on the bottom in such localities, its thickness increasing with time at a rate equal to the rate of delivery of oil minus the rate of oxi- dation in situ. Such layers can indeed be observed on the bottoms of indus- trial harbors. Needed Scientific Activity Although present knowledge tells us that, at least in some cases, no harmful effects can be attributed to the presence of petroleum on the sea — the sea off southern California, for all its dozens of oil seeps, is one of the more productive fishery areas in the world — it would be a mistake to assume that we already have all the information required to settle the question of whether oil on the sea floor is preferable to oil at the sea surface. For one thing, crude petro- leum varies widely in its chemical makeup. We need, therefore, to ex- amine the relative toxicity of crudes from a variety of sources to marine plants and animals, pelagic and ben- thic. We need also to examine the rate of bacterial oxidation of various crudes and to establish the effect of temperature on these rates. We need also to study bottom con- ditions in the vicinity of oil terminals and tidewater oil refineries as com- pared with control areas lacking such industrial activity to determine the extent to which areas of the ocean floor have already undergone the type of modification that has been ob- served in New York's East River — where there is a thick layer of "black- top" in the vicinity of the Brooklyn Navy Yard — and the influence that incorporation of petroleum residues into bottom sediments has had on the benthic biota. And we need to map the various areas of the continental shelves and slopes of the world, down to the depth below which bottom conditions are without influence on fisheries, and to evaluate their pro- ductivity in terms of current fishing operations. At depths greater than about 750 meters, the sinking method of oil dis- persal can presumably be used with- out fear of harmful effects. Over lesser depths, where important de- mersal fisheries exist, only laboratory studies of the effect of sunken oil on the biota can provide pollution- 362 MARIN] NANTS control authorities with the informa- tion that will enable them to evalu- ate whether removal of floating oil through causing it to sink to the bottom is economically preferable to attempting to collect it on the surface, to speed its natural removal by spreading emulsifying agents, or let- ting it drift ashore. The observation of Horn, Teal, and Backus that barnacles thrive attached to floating petroleum lumps and that a pelagic isopod preferentially asso- ciates itself with the same items sug- gests that the components of such lumps are not toxic to these groups of Crustacea. It is generally supposed that the lower-molecular-weight con- stituents of petroleum are more toxic than those of higher molecular weight. It is also true that the vapor pressure and solubility in water of these con- stituents both decrease markedly with increasing molecular weight. It seems likely, therefore, that natural proc- esses in the ocean may act rather rapidly in the case of floating petro- leum residues to leave only the more inert, heavier fractions at the sea surface, the lighter fractions having been either volatilized to the atmos- phere or dissolved in the mixed layer of the ocean above the thermocline. Some direct observations of the change in composition with time of floating oil spill seem highly desirable in this regard. Horn and his colleague;: further suggest that toxic petroleum co nents find their way into the food chain through fish like the saury, which appear to be voracious feeders of anything they may encounter at the sea surface. It would appear to be relatively easy to sample saury from the catches of the wide-ranging Japanese fishing industry, as well as apex predators such as dolphin (Coryphaena), swordfish, and tuna, to determine if, in fact, any accu- mulation of undesirable compounds originating in petroleum can be de- tected. Porpoises, also mentioned by Horn, can be readily sampled through the individuals that are captured acci- dentally in tuna-seining operations. 363 PART X — ENVIRONMENTAL CONTAMINANTS 5. ENVIRONMENTAL DISEASE Malaria Malaria in humans continues to be a major problem in many parts of the world. Uncritical enthusiasm gen- erated in the period immediately after World War II, occasioned by the un- expected appearance on the scene of the chlorinated hydrocarbons, led to the belief that global eradication of malaria was a possibility. National and international agencies invested large sums of money in sweeping pro- grams, built upon the observations that the residual effects of long- persisting insecticides, when these had been applied to the walls of dwellings, would serve to interrupt the transmission of malaria by cut- ting short the lives of the vector anophelines, thus denying to the para- site the chance to infect new hosts. There were early victories in re- gions where the habits of the specific vector species led, in a certain few instances, to actual eradication of the vector or, in other instances, to inter- ruption of transmission and eradica- tion of malaria. In still other instances victory was partial, and marked re- duction in incidence of malaria could he noted. (See Figure X-18) In other instances, notably in Africa, parts of Asia, and parts of South America, results have been disappointing. In the large-scale campaigns, em- phasis was placed almost entirely on control procedures and the intricate logistic problems relating thereto. For a period of two decades, there was a decided slump in the volume of basic malaria work carried on; fundamental studies on parasite biology, host- parasite interactions, drug prophylaxis and therapeusis, and the biology of the anopheline vectors were neglected. The recognition that resistance to insecticides was emerging in anophe- line vectors (not as serious a problem Figure X-18 — CHANGES IN MALARIA MORBIDITY BEFORE AND AFTER MOSQUITO CONTROL Area Year Number of Cases Mauritius Cuba Dominica 1948 1969 1962 1969 1950 1969 46,395 17* 3,519 3 1,825 Nil Dominican Republic 1950 1968 17,310 21 Grenada and Carriacou 1951 1969 3,233 Nil Jamaica 1954 1969 4,417 Nil Trinidad and Tobago 1950 1969 5,098 5 Venezuela 1943 1958 817,115 800 India 1935 1969 more than 1,000,000 286,962 Bulgaria 1946 1969 114,631 10* Italy 1945 1968 411,602 37 Romania 1948 1969 338,198 4* Spain 1950 1969 19,644 28* Turkey 1950 1969 1,188,969 2,173 Yugoslavia 1937 1969 169,545 15* China (Taiwan) 1945 1969 more than 1,000,000 9 imported or induced cases. The table shows the effectiveness of selected mosquito-control programs, most of which use DDT. Over 1,000 million people have been freed from the risk of malaria through such programs. 364 ENVIRONMENTAL DISEASE yet as that seen in Aedes aegypti) provided signals that difficulties could be anticipated in the application of standardized control procedures in regions where earlier work had been successful. Furthermore, malaria para- sites have emerged markedly resistant to the commonly used antimalarials. This has spurred the search for new antimalarial agents and has indicated the need for extension of more basic parasitologic studies. The problem of drug resistance is particularly acute in Southeast Asia. The U.S. Army Research and Devel- opment Command has established a broadly based program of research, largely monitored through the Walter Reed Army Institute for Research, with the collaboration of the U.S. Armed Forces Epidemiological Board and the U.S. Public Health Service. Research efforts have also been inten- sified in a number of other countries. The State of Scientific Knowledge Further discussion requires subdi- vision into a series of topics, often intricately interassociated. Malarial Parasites — Earlier beliefs that malaria was exclusively limited to humans have been modified, since it has been shown that P '.falciparum, P.vivax, and P.malariae can all be passaged to subhuman primates, can establish infections, and that anophe- lines can be infected from such sources and can transmit further to primates. The owl monkey (Aotus trivirgatus) of South America has been particularly useful in these studies, though, unfortunately, it is not readily obtained in large num- bers. Passage of the parasite in such hosts provides material for detailed studies of the host-parasite relation- ship, and is of great value in provid- ing quantities of the parasite for in vitro cultivation and laboratory- controlled studies on parasite metabo- lism, enzyme studies, morphological studies, preparations of antigens, and the like. The importance of extra- human cycles for maintenance of the parasites in nature is of obvious in- terest in epidemiology, and awaits critical assessment. Detailed morphological studies have provided new insights into the anatomy of the parasite. They prom- ise to provide powerful tools for direct observation of the mechanism of action of antimalarial agents on the parasites. Such studies, coupled with studies of the enzyme systems involved in drug action, should point the way to rational development of antimalarial drugs. These studies are intimately related to studies on the basic structure and biology of the red blood cell. There has been a considerable ex- tension of knowledge relating to the exo-erythrocytic cycle of develop- ment of malaria parasites in the ver- tebrate host. This is a particularly important field, since it relates to problems of malaria prophylaxis and to the radical cure of the established infection. Failures in prophylaxis and therapeusis of the non-drug-resistant parasites may be due to failure of the drug to get to the parasite, or the parasite form itself may be less sensi- tive. The former is the likeliest hypothesis. The recognition in recent years that strains of P '.falciparum are markedly resistant to 4-aminoquinolines and to widely used antimalarials has pro- duced a spurt of new research. Proj- ects involve the coordinated efforts of synthetic chemists, biochemists, phar- macologists, clinicians seeing drug- resistant cases (particularly in troops), and clinical-laboratory groups study- ing the new drugs and combinations of drugs under controlled conditions. Several different drug combinations are being used to treat drug-resistant cases; in addition to chloroquine, they employ certain sulfones and certain anti-folic acid agents such as amodia- quine and related compounds. The immediate problem, control of the in- fection in the individual, has in large part been met, but there is much unresolved in studies of comparative efficacy and in evaluation of the pos- sibility that the parasite will develop resistance to a further range of anti- malarial drugs. Intensive search for new antima- larials — not just relatives of known antimalarials — has involved the elab- oration of drug-screening procedures of several types: rodent malaria sys- tems; avian malaria systems; systems monitoring the development of para- sites in mosquitoes or mosquito or- gans, human malaria parasites, using in vitro systems, and, ultimately, ma- laria parasites of humans in humans. Promising leads include phenan- threnes and naphthoquinones, but they are few in relation to the total effort. The "one shot" antimalarial is still a dream. Human Host — A prominent ques- tion remains unsolved: What fac- tor(s) cause febrile paroxysm? Newly developed techniques for fractiona- tion of parasites and for fractionation of infected red blood cells may lead to a resolution of this question. The sickle-cell trait in humans has been well established as exerting a protective effect in P. falciparum, in- fections. A similar situation has been postulated for the G-6-PD deficiency state, but supporting evidence is not convincing. Further combined field and laboratory studies are indicated. The possible relationship of ma- laria to Burkett's lymphome has been advanced on epidemiological grounds; this possibility is currently being studied intensively in East Africa. The problem of hemolysis in G-6-PD deficient subjects treated with 8-aminoquinolines has been promi- nent in troops in Southeast Asia, and the subject of detailed studies. Other drug-treatment problems have been recognized, particularly the de- velopment of irreversible scotomata following prolonged chloroquine therapy, and agranulocytosis follow- ing diaminodiphenyl-sulfane therapy. 365 PART X — ENVIRONMENTAL CONTAMINANTS These latter reactions, although so far few in number, often terminate in death. It is suspected that they may be related to decomposition products in aged stores of the drug. Diagnosis — The classical proce- dure of diagnosing malaria on the basis of finding the parasite remains unchallenged. The paucity of tech- nicians able to apply the established procedures accurately reflects the lack of interest in most medical schools and training centers in tropical medi- cine in general and malaria in par- ticular. Direct immunofluorescence using tagged immunoglobulins to signal the malaria parasites in blood smears is a workable procedure, but it is not ex- tensively used, and not likely to be. Indirect immunofluorescent proce- dures utilizing prepared malaria smears, sera being examined for pres- ence of antibody, and tagged anti- globulins to the host serum have shown much promise, particularly in permitting study of the immune status of populations. It is not probable, however, that such techniques will find application in the diagnosis of the immediate malarial illness in a human. Further refinements are to be an- ticipated, involving the application of newer techniques to obtain purified, or separated, parasite and serum frac- tions. Practical application of such methodology by routine diagnostic laboratories will come slowly, if ever. Vectors — The maintenance of ma- laria in the human community is a reflection of vector-host-parasite in- teraction, as well as environmental factors. (See Figure X-19) The vector must have an association with hu- mans, and the parasite must be avail- able. This relationship is highly com- plex put nonetheless subject to analy- sis by construction of models which can be adapted to computer analysis. Macdonald's contributions to such a model are well known. It becomes apparent that many or most of the variables introduced into the equation are ill defined, and that many of these relate to the mosquito vectors. A single model can only ap- ply to a single vector, and there are several dozen well-recognized vectors. For each vector, field information is necessary relating to distribution, densities, longevity, flight range, feed- ing habits vis-a vis humans as con- trasted to other blood or food sources, resting habits, frequency of refeeding, susceptibility to insecticides, and sus- ceptibility to the malaria parasite in question. As such questions are ex- plored, there is frequently need for more specific taxonomic detail, and certain of the earlier recognized vec- tors, such as Anopheles gambiae, have been split into a series of recog- nizable entities (races? species?) with distinctly different biology. Control — This topic must be con- sidered with respect to the several ac- cessible components: the parasite, the host, and the vector. The finding of drug-resistant para- sites complicates greatly the already complex problem of control through direct attack on the parasite through mass chemotherapy of human popu- lations. Drug-resistant parasites have thus far not been recognized in Africa. Should they be transplanted there through migrations of parasitemic hu- mans, or through development locally, the result would be disastrous. The host can be approached through immunization procedures. Recent work in rodent malaria systems on developing immunogens derived from sporozoites is encouraging enough to merit extension of such studies to hu- mans. Other approaches to the host, apart from such obvious measures as use of protective clothing, bed nets, and insect repellents — all of limited effectiveness unless conscientiously employed — have centered largely on the insect-repellent aspect. An ap- proach through development of sys- tematic insecticides or repellents, which have had some success in pro- Figure X-19 — AREAS OF MAJOR MALARIA POTENTIAL Malaria mosquitos cannot survive in areas where temperatures fall below 15° centi- grade and annual rainfall is less than 1,000 millimeters. By combining the 15° centigrade isotherm (broken line) and the 1,000-millimeter isohytel (solid line), one can determine the areas where mosquito survival is continuous (shaded sec- tions), with consequent heavy risk of malaria, and the areas (hatched sections) where unusually heavy rainfall can permit mosquitos to survive and malaria to spread. 366 ENVIRONMENTAL DISEASE tecting livestock, does not hold much promise for human use. More effec- tive repellents are being sought, but prospects for compounds appreciably more effective than those now used are dim. Vector-control programs through the application of residual insecticides have had distinct success; there have also been failures. In part, the failures have resulted from development of resistance to insecticides; but in greater part failures have been due to biological behavior patterns of the anopheline species in question, pre- cluding effective exposure to residual insecticides. Larviciding techniques, particularly including low-volume aerial application of insecticides, are in a phase of reassessment. New techniques of vector control, using genetic manipulation, insect pathogens, antimetabolites, and insect hormones are currently attracting much attention. Genetic manipulation includes male sterility induced by ir- radiation of chemosterilants, cytoplas- mic incompatibility, and translocation semisterility. Successful application of such techniques will require much more comprehensive knowledge of the biology of each anopheline species under consideration than now exists. In this connection, the biology of the nonbiting males of the many species has received little attention in the past but may well be critical in at- tempts at genetic manipulation of populations. A related approach involves at- tempts to replace a vector population of one species by a nonvector popu- lation of a different species through competitive displacement. Such an ex- periment is now under way on a Pa- cific atoll, attempting to displace the filaria vector species. The concept could also be applicable to displacing a parasite-receptive clone of a vector species by a parasite-resistant clone of the same species. Epidemiology — Studies relating to the central problem — the under- standing of the epidemiology of ma- laria in human populations — are indicated at various points in the pre- ceding discussion. It must be further pointed out that epidemiological studies today are greatly embarrassed by the various types of partial control which may be operating in a field lo- cality, including partially effective drug therapy with many drugs, chang- ing agricultural and living habits of populations, and partially effective vector-control programs. In the proc- ess of measuring, variables change and the picture changes. This situa- tion cannot be controlled and will not change. Need for Trained Manpower Especially important is continuing training of field epidemiologists, with enough background to permit them to work effectively on actual field prob- lems of malaria in overseas locations. This should include medical person- nel, entomologists, and control ex- perts. Most of the medical schools in the United States and in the world do not meet this problem adequately, and attention should be given to the strengthening of several centers that can be recognized as training centers for tropical diseases in general and malaria in particular. Other Parasitic Diseases Many parasitic infections are, in fact, zoonoses with significant inter- relation between man and domestic or wild animals — e.g., hydatid disease, American trypanosomiasis, leishmani- asis, and fascioliasis. Study and con- trol of such parasitic diseases are seriously neglected though they cause immense losses — both social and economic. These are diseases of the poor and ignorant, which can, in part, explain the neglect since those people have little political leverage. Nevertheless, the fund of information on the dis- eases and their control has run ahead of the development of sound and use- ful control programs. Most existing control programs are weak and inade- quate despite the gravity of the prob- lems. Somehow this pattern of neglect has to be broken. Schistosomiasis Schistosomiasis is a worldwide scourge in regions containing about 592 million people. (See Figure X-20) About 125 million people are infected. About 2.6 million are totally disabled by it and 24.8 million are partially dis- abled. In Brazil alone, approximately 15.5 million people live in affected re- gions and 5.8 million are infected; 116,600 are totally disabled and 1.4 million are partially disabled. The estimated economic loss to Brazil due to the "loss of resources" (i.e., loss due to reduced productivity of goods and services alone) is estimated to be about $106 million per annum. The disease is out of control in al- most all endemic areas and has spread or increased in prevalence in Africa, the Philippines, and Brazil in recent years. In these areas, the increase has been due to migration of infected peo- ple, opening up of new areas for settlement, or water resources devel- opment schemes. Schistosomiasis demonstrates par- ticularly well the complex feedback among human health, agriculture, in- 367 PART X — ENVIRONMENTAL CONTAMINANTS Figure X-20 — WORLD DISTRIBUTION OF SCHISTOSOMIASIS The maps show the distribution of various forms of schistosomiasis. The disease is a major block to agricultural progress in many of the world's developing nations. 368 ENVIRONMENTAL DISEASE dustry, social structure, social change, and economic development. The dis- ease affects mainly the poorer people closest to the soil. Low economic status promotes the disease because it forces people to live in unsanitary conditions. Ignorance is also a major factor in lack of sanitation. The dis- ease causes significant illness and de- bility in a large proportion of the infected population. These people compete less well and are less produc- tive. The disease, then, holds them down. Farmers, because of the nature of their work, are more often exposed to the infection. Urbanization reduces the danger of spread of the disease, but water resources development schemes — with their dams, irrigation systems, and water-level-stabilization activities — promote the transmission of the disease. Water resources devel- opment schemes that can produce significant economic and social ad- vancement can be severely weakened by the spread of this disease that can result directly from the changes the schemes require. Current Scientific Knowledge — We know enough to control schistosomi- asis in most of the endemic zones. The way to do it is by reducing snail populations and contact of man with "infected" water. New molluscicides offer a reasonably economical oppor- tunity to reduce transmission drastic- ally. New drugs are in development that offer for the first time a hope for easy treatment with reduced toxicity. There is no reasonable prospect of a vaccine or other means for control of the disease except, perhaps, for use of competitor snails in some localities. Needed Activity — The technical base is thus reasonably good. Of course, more information would help. Safer drugs, easier snail control, and a way to vaccinate against the disease can be hoped for. Recently, there has been a series of efforts to produce mathematical models for analysis of transmission problems and for predic- tion. They are in the exploratory phase and are not really predictive yet. Figure X-21 is one input to such a model. But control schemes will need more trained people, support, and — per- haps hardest to get — good national organizations devoted to the problem. We have spent enough time "finding out" what we need to know about the problem. We need to get on with con- trol schemes and continue to learn as we go along. A strong push could work wonders in control of the dis- ease in a number of countries. Chagas' Disease (American Trypanosomiasis) Chagas' disease occurs in almost all American countries and exists in re- gions inhabited by about 35 to 40 million people. At least 7 million are usually considered to be infected, though the number is sometimes esti- mated to be as high as 10 million. In some endemic zones, 50 percent or more of the people are infected; of these, 10 to 20 percent have signifi- cant cardiac damage or intestinal-tract damage due to the infection. Morbid- ity and mortality data are not very good. One careful study of the causes of death that occurred in Ribeirao Preto, Brazil, over a two-year period showed that the disease was the cause of 29 percent (40 out of 139) of the male mortality in the 25 to 44 year age group — a shocking figure. Ar- gentina considers that it has 2 million infected citizens and 400,000 with heart damage or other significant con- sequences of the infection. Venezuela has about 2.8 million people exposed to the infection in the endemic zones and about 560,000 infected persons, of whom about half have significant cardiac damage as a result. Chagas' disease is a disease of the poor, ignorant, and badly housed. It is primarily rural, though some cities are heavily affected in the poorer parts. Poverty and lacl tion results in constrm bad houses of poor materials and in poor maintenance of houses. Such houses are excellent harborages for the insect vectors. The disease produces, in a proportion of its victims, acute illness followed by delayed cardiac or diges- tive-tract damage. These can termi- nate in heart failure, invalidism, and loss of productivity. The disease strikes particularly hard among young adults in their most productive years and when their families are most vulnerable to economic stress. The circle of poverty-ignorance-sickness- economic failure is a difficult one to break. Venezuela is the only country with a control program of a size and sig- nificance commensurate with the size of the problem. A few other countries have limited control programs (partic- ularly Chile, Brazil, and Argentina). Many countries do not know the mag- nitude of their problem with any ac- curacy at all though in many of them there is undoubted widespread mor- bidity due to the disease. Current Scientific Knowledge — Knowledge of the disease is now ade- quate for effective control. What is needed is the decision that control is worth the cost and that it must be undertaken. Systematic use of insec- ticide (benzene hexachloride or diel- drin) can cut the transmission rate to a low level. Spraying costs $5 to $10 per house and may have to be repeated every two to three years. This is relatively costly, considering the political and economic status of the people affected and considering the inability of most of the countries to spend large sums on disease control. In a number of countries, it is nec- essary to determine the importance of the problem. This can be done by systematic sampling to determine prevalence of infection (serological test) and prevalence of significant morbidity (electrocardiogram). Both are technically feasible in any country. 369 PART X — ENVIRONMENTAL CONTAMINANTS Figure X-21 — EJECTION OF SMALL DROPLETS INTO THE ATMOSPHERE BY BURSTING BUBBLES THIS SEQUENCE OF PHOTO- GRAPHS SHOWS THE COL- LAPSE OF A 1.7 mm DIAME- TER BUBBLE AND THE FOR- MATION OF A JET. THE TIM.E INTERVAL BE- _ TWEEN FRAMES 1 AND 4 £ IS ABOUT 2.3 MILLISECONDS. OBLIQUE VIEW OF THE JET FROM A t mm DIAMETER BUBBLE C=^T r # BACTERIA/, r ^ .: '. i -.- yj-. . . j i . — •**.v.*.V • w.v ■/••• • : *.* :* * • •.-. v.v * : • .' ■.-;©■■ '• CONCENTRATION OF BACTERIA IN JE" DROPS FROM BURSTING BUBBLES The diagram shows how disease-laden water vapor can enter the atmosphere. When a droplet of water such as rain falls out of the atmosphere through a surface of water, its shape changes and shortly triggers a jetlet, which is then ejected up- ward from the water surface. A droplet of water from the jetlet remains in the atmosphere, while the rest of it collapses. A similar situation occurs when bubbles formed beneath the water surface, as by decomposition, rise to the surface and burst. If, in either of these cases, the water surface is contaminated, then con- taminated droplets enter the atmosphere and may be transported great distances. It is thought that hoof-and-mouth disease spreads in this manner. Needed Activity — Priorities for re- search include: 1. Improved and more economical diagnosis; a simpler serological test. 2. Expanded exploration of possi- bilities for a vaccine. 3. A breakthrough on measures for vector control, particularly since the insecticides now relied on may have to be discouraged because of their cumulative tox- icity in the environment. (One household may require several kilograms of 5-percent benzene hexachloride for each spraying, and some houses have been sprayed several times. The rate of application is 0.5 gram of the active insecticide per square meter of surface inside and out. Latin America has enough well- qualified people in the subject. Those in research need financial help. If they are in national control programs, they need advice and support. Most coun- tries need to be pushed into more ag- gressive control efforts. The immuno- logical studies can be supported both in and out of the endemic zones. In- ternationally supported control cam- paigns to improve, not replace, houses and to spray houses could have a dramatic impact on the disease. 370 PART XI HUMAN ADAPTATION TO ENVIRONMENTAL STRESS GENETIC ADAPTATION TO THE ENVIRONMENT An evaluation of man's adaptation to the environment depends, obvi- ously, on the use of the two key words, adaptation and environment. To begin with the latter, its use in connection with adaptation usually brings to mind the physical environ- ment — climate, etc. — but the bio- logical environment of a species, in the form of disease or predators, is also well known. Furthermore, many of the important problems of man's adaptation are now concerned with the psychological or social environ- ment. People are as much a part of the environment as sunlight and rain- fall, and the problems of man's in- traspecific aggression and population control must take into account adap- tations to this environment. If the definition of environment is extremely general, even nebulous, the definition and uses of the concept of adaptation are even more so. In fact, there is considerable confusion as to the nature of man's "adaptations" because of the very loose use of the term. General systems theory, for which adaptation is a central concept, can be applied to everything from physical systems or phenomena to cultural change. Even within the bi- ological sciences there are many uses of the term adaptation. However, the most general use is to define genetic adaptations, which are changes in the gene frequency of a population in response to or as a result of differ- ences in the fitness of the genotypes. Adaptation will here be used only in this restricted, genetic sense. Darwinism Revived As an explanation of human ge- netic differences, the concept of adap- tation — or, what is synonymous, natural selection — has only assumed its rightful place in the past twenty years — even though it was Darwin's major contribution to biological sci- ence. For almost 100 years after Darwin, biologists and anthropolo- gists concentrated on constructing taxonomies and phylogenies, which were based on the similarities and differences among populations of or- ganisms and were based, implicitly and explicitly, on the assumption that these similarities and differences were "non-adaptive." In anthropology, the switch to adaptive explanations began about 1950, with Coon and others, and was concerned with the visible, measur- able features of individuals that are commonly called racial traits. At about the same time, there was new work and rediscovery of old work on the association of the ABO blood groups and various diseases. The rediscovery of the work done in the 1920's was comparable in a way to the rediscovery of Mendel, in that its significance was now recognized. This recognition was due to the re- discovery of natural selection as a major factor in the evolution of human differences. Again in the early 1950's, research showed that sickle cell anemia and thalassemia varied in frequency in different "races"; they occurred with extremely high frequencies in some populations. Since these diseases were known to be due to homo- zygosity for a single gene (the situa- tion is somewhat more complicated now) and were extremely severe if not lethal, their prevalence raised some knotty problems for population geneticists. With such selection against these genes, there had to be some other force balancing this ad- verse selection and thereby causing the high frequencies. Although there is still some disagreement — mostly as to details — it is generally accepted that heterozygotes for the sickle-cell gene have a resistance to falciparum malaria; thus, adaptation, or natural selection, is the major explanation for differences among human popu- lations in the frequency of the sickle- cell gene. This exampli that it is used in just about textbook. Science, like the rest of human endeavor, evolves by a pendulum process. Thus, when these three trends re-introduced adaptation into the study of human genetic variation, adaptive explanations began to be proposed for most genetic differences. The result was an exaggeration of the concept that was almost as faulty as its total absence had been in previous work. In the sickle-cell example, the racial and polymorphic traits that were explained by adapta- tion required this concept; they were obviously genetic differences, and other explanations seemed inadequate due to problems such as the extreme selection against the sickle-cell gene. After the pendulum swung, explana- tions by adaptation were extended to all genetic differences and to many behavioral differences between popu- lations. These extensions raise two questions: (a) how many genetic dif- ferences are explained primarily by selection, and (b) how many of the functional or behavioral differences between populations are primarily genetic and due to different adapta- tions? Selection as an Explanation for Genetic Difference The first question is now being hotly debated by geneticists. The debate began with Muller's discus- sion of "our land of mutations" and was continued with his paper in as- sociation with Morton and Crow. One could almost label this "the American position," which considers most genetic loci, or the allelic vari- ability at most loci, as due to a balance between mutation from the normal allele and selection against the abnormal variants. The state- ment that most loci are generally described in this way is reasonable; 373 PART XI — HUMAN ADAPTATION TO ENVIRONMENTAL STRESS but Morton and others have gone beyond this position to say that most selection, and particularly that in- creased by inbreeding, is associated with this type of locus and acts to reduce genetic variation. The other position is that many loci are balanced polymorphisms in which the selection against the two homozygotes balance each other and result in genetic vari- ability; the sickle-cell locus (/? hemo- globin chain) is the most obvious example. Both sides agree that both kinds of loci exist. The questions are how many of each and how important for human genetic disease are the two kinds. Recent estimates of the number of polymorphic loci — in other words, loci with at least two different alleles with appreciate fre- quencies in a significant number of human populations — have ranged around 30 to 35 percent of all human loci. Thus, while the majority of loci may well be mutational, problems and arguments must still be resolved in order to explain the 35 percent that are polymorphic. How much of this polymorphism is due to adaptation or natural selec- tion, and how much is simply "neu- tral" variation? This is one of the major concerns at present. Again, the Americans (and the Japanese, fol- lowing Kimura) are working on the assumption that most of this varia- tion is "non-adaptive," while the British are more skeptical. The ar- gument seems to go back to the famous encounters between Fisher and Wright on the significance of random genetic drift. In addition, the assumption of "non-adaptive" differences among human populations is basic to the reconstruction of phylogenies or taxonomies; recent work on the adaptive significance of racial differences thus tends to cast doubt on previous work on race. However, the opposite position — that all polymorphic differences are adaptive — also rests on thin ground. For example, in European populations the frequencies of cystic fibrosis ap- proach those which would be labeled polymorphic; in Eastern European Jewish populations the frequency of Tay-Sachs disease does, too. For these two loci there has been con- siderable speculation on the adaptive significance of the abnormal allele, although one need not assume selec- tion for the abnormal allele in these cases. Much work has also been done on blood-group systems other than ABO in an attempt to demon- strate the action of natural selection. Selection against heterozygote Rh babies due to maternal-fetal incom- patibility obviously exists, but the attempts to show selection in relation to environmental factors have not been very successful. Thus, the posi- tion that almost all genetic differences among human populations are due to adaptive selection cannot be said to have been proven; on the other hand, to assume that any locus is "non-adaptive" because we cannot demonstrate the selection that may be involved is also tenuous. How much selection would be nec- essary to develop the human genetic differences we observe? To a great extent, the answer appears to be "infinitesimal" — or certainly within the range of error of the measure- ments on modern human populations by which we are trying to detect selection. This is due to the uncer- tainties of sampling and the limited size of the most significant human populations presently under study, such as the Yanomama Indians of Brazil and Venezuela (see Figure XI-1), who are among the few re- maining hunters and primitive horti- culturalists. And yet we know that human populations do change. De- spite their seemingly small genetic differences (see Figure XI-2), Yano- mama and Japanese are clearly very different human types. Given this di- lemma, we are likely to decide be- tween competing theoretical positions on the basis of their ability to explain the totality of human genetic varia- tion as it exists today and not on the basis of hoping that we will ever be able to measure the amount of selection that existed 10,000 or 20,000 years ago. And our explanations will contain both instances where genetic drift, or the "founder effect," were far more important factors of gene- frequency change than selection and vice versa. Adaptation to Explain Behavioral Differences So much for the increased effect of our knowledge of adaptation on known genetic differences. We now turn to the other extension of the concept of adaptation. To recapitu- late, adaptation was revived as an explanation of human genetic differ- ences because there were certain dif- ferences among human populations that could not be explained without it. Adaptation was then extended to most other widespread genetic dif- ferences; it was also extended by anthropologists, physiologists, psy- chologists, sociologists, and even edu- cators to other biological or beha- vioral differences among groups. If a group could be shown to be geneti- cally different in one trait, it was assumed to be different in many other traits and, in addition, any differences that were found among such groups were implicitly assumed to be genetic. The resurgence of Darwinian think- ing has been pronounced in behavi- oral studies. These include a great number of studies of physiological responses to environmental stresses such as temperature as well as studies of the intellectual functioning of the organisms, which usually fall under the heading of behavioral genetics. There is an important difference be- tween these studies and earlier ones concerning human differences that required adaptive explanations. The latter involved known structural dif- ferences that could be related to gene action. For example, the differences in skin color among human popula- tions are very pronounced, are known to be genetic, and, although some investigators do not think it is 374 GENETIC ADAPTATIONS TO THE ENVIRONMENT Figure XI — 1 —DISTRIBUTION OF THE YANOMAMA INDIANS IN SOUTH AMERICA proven, require some adaptiv: ferences in the skin-color genotypes in various environments to explain them. The physiological basis of this selection has not been demon- strated, but there is still no other reasonable explanation in genetic theory for these differences. The fact that skin color seemed to be a climatic adaptation may have given rise to the idea that there must be many more climatic adaptations in man. At first it was hypothesized that gross structural differences may exist; but studies have shown that the number of eccrine sweat glands as well as the number of melanocytes are about the same, and their dis- tribution on the body is also the same in all groups of men. The small map shows the general location of the Yanomama Indians. The large map shows the detailed location of their villages. Two villages located near the Venezuelan-Brazilian border are those from which blood samples for the cytogenetic studies were obtained. Although human structures and basic responses to climatic stresses are about the same everywhere, many physiological studies have shown dif- Figure XI-2 — CYTOGENETIC FINDINGS IN 49 YANOMAMA INDIANS FROM TWO VILLAGES IN VENEZUELA In Jungle Japanese Males Females Totals Controls Controls Number of Cases 32 17 49 2 174 Number of Cells Examined 3175 1700 4875 250 16,035 Per Cent Cells with 46 Chromosomes 96.7 97.1 96.8 97.0 95.6 Number of Cells with One or More Abberrations: Total 139 (4.38%) 61 (3.59%) 200 (4.10%) 5 (2.00%) 157 (1.0%) Single chromatid breaks 80 (2.52) 32 (1.88) 112 (2.30) 4 (1.60) 105 (0.65) Isochromatid breaks 20 (0.63) 13 (0.76) 33 (0.68) 1 (0.40) 23 (0.14) Free fragments 13 (0.41) 6 (0.35) 19 (0.39) 0 (0.00) 10 (0.06) Dicentrics 3 (0.09) 1 (0.06) 4 (0.08) 0 (0.00) 1 (0.006) Rings 1 (0.03) 0 (0.00) 1 (0.02) 0 (0.00) 0 (0.0) Translocations, inversions 0 (0.00) 0 (0.00) 0 (0.00) 0 (0.00) 8 (0.05) Chromatid exchanges 3 (0.09) 4 (0.24) 7 (0.14) 0 (0.00) 5 (0.03) Centromere breaks 2 (0.06) 2 (0.12) 4 (0.08) 0 (0.00) 5 (0.03) No. of Complex Cells 17 (0.54) 4 (0.24) 21 (0.43) 0 (0.00) 0 (0.0) The table shows cytogenetic differences between some Yanomama Indians and several control populations. The data are compatible, since the same culture methods were used except that the Japanese control cultures were not delayed in the initiation of the 72-hour cultures. Complex cells include those with multiple, exchange-type aberrations. 375 PART XI — HUMAN ADAPTATION TO ENVIRONMENTAL STRESS ferences. Australian aborigines lose heat to permit a lower temperature in their extremities; Eskimos quickly warm their fingers in an ice bath; Africans sometimes sweat less in re- sponse to heat. All of this is blithely called adaptation, with the presump- tion that it has a genetic basis. This work is comparable in method, theory, and genetic bias to the studies of psy- chological differences, many of which have involved "IQ" tests that purport to tind racial differences in intelli- gence. The logic of such studies is that genetic adaptations to environ- mental differences must exist, and the only problem is to discover them. The result of these extensions of the concept of genetic adaptation has been to take a well-defined concept and make it a hodgepodge for any- one to use. To an extent, this is char- acteristic of areas of science that are developing rapidly or are in fer- ment — and behavioral and physio- logical genetics are certainly doing that. The major confusion results from the use of structural differ- ences— i.e., genes — to describe func- tional or behavioral differences, with- out recognition that vast differences in behavior are the result of the environment or of other kinds of "adaptation" to the environment. Perhaps we are back to the old nature-nurture controversy, but there has been some progress. Great strides have been made in the analysis of behavior by the methods of quantita- tive genetics, and these methods can be applied to physiological differences to some extent. But the measure of genetic determination — heritabil- ity — applies only to the population studied and to the differences among the individuals within it. Within any population, as well as between popu- lations, individuals vary in response to any biological and psychological test. William has continually stressed the uniqueness of the individual for just about anything biological that one can measure. And it is true that tests of biological relatives indicate that some of this variation is due to heredity. But it is a totally different problem to explain differences be- tween populations. It seems reason- able to most people that these dif- ferences must also have about the same genetic component; but that is not the case. We are only just beginning to realize how powerful environmental influences are in affecting the total functioning of the individual. "Adap- tation" — whether to temperature change, to disease, to crowded con- ditions, to learning school work — results from spending one's lifetime in a particular environment; putting two different groups in the same cold chamber, school, or hospital for a day, a week, or even a year is not a "controlled" experiment that will prove genetic or racial differences. For example, it was long thought that "natives" had a natural resistance to some diseases and whites to others such as TB. However, we are now seeing that resistance is a function of previous exposure, amount of ex- posure, and age at exposure; sim- plistic notions of racial immunities are not very realistic. One cannot say, however, that sig- nificant differences do not exist or that there are no genetic factors in- volved. American Negro troops in Korea did suffer four times as much from frostbite as whites; this is a problem that needs explaining. Amer- ican and West African Negroes do seem to have an almost total resist- ance to vivax malaria, which also seems to be genetic. Many of the populations in Europe and Africa that depend on milk for subsistence have an active lactase enzyme (among adults), while most of the rest of the world's populations are lactase deficient. Nevertheless, most of the behavioral differences among popu- lations that have been called adapta- tions do not require or demonstrate genetic differences; rather, they have been proposed on the basis of tenuous data and a misunderstanding of the populational significance of adapta- tions. Applicability of Animal Ethology There is one other area of research in which the concept of adaptation has played an important role. This is the application of animal ethology to human characteristics. Lorenz on aggression, Ardrey on territoriality, Morris on sexual behavior, and others on all other kinds of behavioral traits have attempted to develop adaptive, or "Darwinian," explanations for these traits. Ethology in its methods and theories is quite comparable to behavioral genetics, although the lat- ter concentrates on human data while the former generalizes to man on the basis of analogy with animals. To show that man is comparable to the other animals in many ways is commendable, but it is still impos- sible to explain the variation in hu- man behavior among populations by biological or genetic factors. Aggres- sion is not universal among human populations; and it is the variability in this characteristic that is the an- thropologist's problem. To disregard this variability — as does Morris, for example, by saying that the rest of the world's cultures are evolutionary backwaters — is simply fatuous. As any other species, however, man does have some species-specific characteristics; and these are un- doubtedly due to a long period of adaptation to a common ecological niche, which in his case was hunting with tools on the savannahs of the Old World. But again, to explain what is "wrong" with human socie- ties today by genetic lag is not ade- quate. If it were, then all human societies should have these aggressive genes stemming from our carnivorous past. But not all societies are as aggressive as ours. Most ethology- oriented scientists seem to view man's cultural evolution as simply social change which adjusts culture to man's biological "needs." This view tends to detract from the power of the environment to change human char- acteristics — if one can view cultural pressure as the environment. It also 376 GENETIC ADAPTATIONS TO THE i tends to overemphasize the signifi- cance of genetic adaptation for the survival of populations. Adaptation and the Future of Human Society Because fitness expresses the ability of individuals to survive — as well as to reproduce — fitness differences among individuals or genotypic dif- ferences among papulations are usu- ally assumed to have considerable ef- fect on the population's survival in the course of evolution. However, geno- typic evolution has minimal effect on a population's ability to survive. The huge variation in mortality and fertility rates among human popula- tion has practically no relationship to genetic variation. Darwinism seems to have given rise to such statements as "the polar bear survives in the arctic because it is adapted to that environment"; but in terms of the course of evolution, the opposite is true — that is, the polar bear is adapted to the arctic because it has survived there. Again, Coon has stated that Negroes survived in ma- larial environments because they had the sickle-cell gene. But why do several African populations have high frequencies of this gene? Because they have survived for centuries in a malarial environment. (See Figure XI-3) If, with a simple model for this sickle-cell locus, one compares the average fitness of a population with a high frequency of the sickle- cell gene to that of one with no sickle- cell genes, the difference is at most 5 percent per generation. In terms of a difference in mortality rate, this is about 2 per 1,000 per year — which is insignificant when compared to the vast differences in African mortality rates that are due to cultural differ- ences. Genotypic evolution is the result of competition between individuals within a population and has little effect on population competition. Similarly, genes have little effect on other aspects of culture. Cultures can make any kind of martyr, from kamikaze pilot to celibate, any time one is needed; genetic differences in behavior traits are thus not the major, or even a minor, cause of cultural evolution. Even within a population it is usually considered that such traits as dominance are genetically determined; but recent research is pointing to the opposite view: that the greater size, intelligence, aggres- sion, etc., of dominants is the result of being dominant and not vice versa. This is only more evidence that "adaptations" that are almost auto- matically assumed to be genetic may actually be environmental. In summary, there have been siderable advances in our knowlec of genetic adaptation where the ac- tual genes are known, although its effect vis-a-vis the other determinants of genetic change is being debated. On the other hand, the extension of the concept of genetic adaptation to other human characteristics is still much in limbo. This review has been mostly critical of such work — not because it is valueless but because of its very significance for our knowl- edge of human society. Already, some are saying that genetic in- Figure XI-3 — FREQUENCY OF SICKLE-CELL GENE IN LIBERIA >.ioo .075-.100 § .050-.075 Kff^j .025-.050 I 1 .005-.025 The map shows the percentage frequency of occurrence of the sickle-cell gene in the Liberian population. The malaria parasite has been endemic throughout most of Liberia, but the sickle-cell gene varies greatly among tribal populations. The latter variation may be due to the length of time that different Liberian populations have been exposed to malaria. P. falciparum, the malaria parasite is spread by the mosquito Anopheles gambiae, which cannot breed in heavily shaded rain forests. Thus, it— and malaria — were able to advance where rain forest was destoyed to provide land for agriculture. Slash-and-burn practices began in northern Liberia and gradually spread southward. Today, the gradation of the sickle-cell gene follows this same pattern, thus illustrating on a microscale how the evolutionary process operates. The highest frequency of the sickle-cell gene exists where the rain forest has been opened up for the longest time. 377 PART XI — HUMAN ADAPTATION TO ENVIRONMENTAL STRES5 equality is somehow incompatible with "all men are created equal," or that the division of labor is based on "natural inequalities." Thus, the political doctrines of our society are considered to be based on unsound biological assumptions. On the other side, there seems to be resistance to the idea that any racial characteristic is adaptive; this is the result of ex- tending the concept of genetic fitness to an ideal of individual worth. In any case, the entire controversy is, or ought to be, irrelevant to the ideology or aims of our society. ASPECTS OF MAN'S ADAPTATION IN THE TROPICS From our vantage point in the temperate zones, we look upon man in the tropics as having undergone extensive adaptations. In fact, how- ever, man probably arose in tropical zones, living in small bands in the rain forest; from the standpoint of evolutionary biology, it is we of the highly civilized countries who are now making adaptations to a rapidly changing world. In recent years, some groups of investigators have undertaken exten- sive, multidisciplinary studies of the surviving groups of primitive man, these almost without exception in tropical or subtropical zones. In the broadest sense, it is the purpose of these studies to define the popula- tion structure of primitive man, and to appreciate the various pressures (disease, nutritional, etc.) which, in- teracting with that structure, pro- vided the milieu within which human evolution has occurred. It seems ap- propriate to point out that, in many respects, ours is the first generation of scientists to have the facilities for studies of much deeper significance than those of the past, and the last generation to have the opportunity, since relatively undisturbed primitive man is rapidly disappearing from the face of the earth. With respect to this matter of un- derstanding better the population structure of primitive man in the tropics, the geneticist is concerned with such matters as: the amount of inbreeding; the extent of polygyny; birth rates; neonatal, infant, and child death rates; marriage patterns, etc. These factors define the stric- tures that are placed on the evolu- tionary process. Genetic Differentiation The studies of most groups of investigators agree in suggesting that early man in the tropics was charac- terized by high levels of inbreeding. They suggest that infertility was un- common and the reproductive per- formance of woman relatively uni- form. On the other hand, because of the institution of polygyny, male reproductive performance was some- what more variable than in the United States today. The health of the chil- dren appears to have been better than those of most peasant popu- lations. Studies of the frequency of a vari- ety of genetic markers in the isolated villages that comprise most tribal populations reveal a marked degree of genetic microdifferentiation — i.e., there are rather large genetic dif- ferences between the villages that compose a tribe. These villages are engaged in a constantly shifting pat- tern of hostilities, one with the other; that is, competition between demes is a varied risk. This population struc- ture is one that population geneticists feel is particularly conducive to rapid evolution. Health Patterns With respect to the matter of inter- action with agents of disease, mem- bers of these tropical populations have unusually high levels of gamma- globulin. Because of transplacental transfer, a child thus comes into the world with considerable resistance to local pathogens, conferred on it by its mother. As the child comes into active contact with the many disease agents in its surroundings, it will to some extent be protected by pla- centally transmitted maternal anti- bodies, so that it may have an oppor- tunity to build up its own resistance more slowly. The commitment of many of these primitive groups to regulation of pop- ulation numbers is noteworthy. By a variety of means — intercourse ta- boos following the birth of a child, prolonged lactation, abortion, and in- fanticide — the entry of new life into the population is rather rigidly con- trolled. Under these circumstances, an infant may be nursed for as long as three years; in general, the nutri- tion of children is quite excellent. In this respect, many civilized com- munities may have lost an adaptation well recognized by primitive man. Goiter — With respect to specific diseases, a number of examples may be cited as to how markedly many of these people differ in their physio- logical adaptations from ourselves, and how rapidly these adaptations are altered by acculturation. An out- standing example is with respect to iodine. Some of the least-touched groups of South America live in areas where iodine is in very short supply, and yet they do not show goiter. On the other hand, endemic goiter is a prominent feature of civ- ilized populations living under con- ditions of short iodine supply. Studies indicate that at least one primitive group in South America (the Yano- 378 ASPECTS OF MAN'S ADAPTATION IN THE TROPICS mama) has very high uptake levels of radioactive iodine, levels that, in civilized areas, are characteristic of people with quite large goiters. It begins to appear that the development of goiter in the so-called endemic- areas involves more than simple io- dine shortage, that there is some environmental factor which interferes with the utilization of iodine but which can be offset by the use of doses of iodine. Diabetes — A second example is provided by diabetes mellitus. In some of the Indian groups of south- western United States, diabetes is appearing with a great frequency and many complications. Although the evidence is scanty, the disease does not seem to be particularly prevalent among unacculturated In- dians. The most obvious difference between Indian groups with high rates of diabetes and those with low rates is the greater amount of obesity and the lesser amount of exercise of the former. Thus, diabetes mellitus may represent a breakdown in adap- tation to a changing way of life. Caries — For a third and final ex- ample of how the adaptations of primitive man in the tropics are altered by acculturation, one might mention the well-known example of caries. Most relatively untouched groups of primitives are almost caries-free. But within a few years of acculturation, caries often become rampant. The reason is still not clear. Understanding of any of these three phenomena would contribute greatly to our knowledge of man's adaptation in the tropics as well as in other regions. There is a widespread feeling that, given today's rapid changes in man's way of life, the selective forces that shaped him and brought him thus far are rapidly being altered. Studies such as the ones briefly sketched here can provide concrete insight into the way these forces are being altered. Many of the conclusions will have to be inferential rather than demon- strated. Even so, it is hoped that such studies will provide a perspec- tive on the extent of the changes now occurring in man's way of life and some of its problems and conse- quences. ADAPTATION TO HIGH ALTITUDE In the autumn of 1967, two inter- national conferences were held to assess the state of knowledge about high-altitude effects on man. One of these was sponsored by the U.S. Army Medical Research and Devel- opment Command, the other by the World Health Organization (WHO), the Pan American Health Organiza- tion (PAHO), and the U.S. Interna- tional Biological Program (IBP). Be- tween the two conferences, all major laboratories and research groups working in this problem area were represented. Results were reported of a decade of intensified research effort in the United States and abroad. Information Level as of 1967 The basic physiological and psy- chological effects of altitude on low- landers moving rapidly to high altitudes had been described and verified by the late 1950's. In the early 1960's, research proceeded along these lines: 1. Intensified physiological re- search on the consequences of moving men rapidly from low to high altitude. 2. Study of the physiology and general biology of high-altitude natives in Peru, Nepal, and the United States. 3. Investigation of medical prob- lems peculiar to men living at high altitude. The details of the findings avail- able from these pre-1968 studies are too lengthy to cite in a short report, but some of the highlights were: 1. A detailed description of the physiological and psychological limits of low-altitude man's al- titude tolerance. This included a partial knowledge of how much improvement could be expected in performance ca- pability with time and some knowledge about the utility of drugs in modifying altitude tolerance. 2. The study of high-altitude na- tives demonstrated them to be different from lowlanders in a number of general biological and specific physiological pa- rameters. These differences in- cluded an increased incidence of neonatal deaths, different growth patterns, an oxygen- consumption capacity above that of the lowlanders going to altitude even for an extended time (see Figure XI-4), and, fi- nally, a number of unusual dis- ease characteristics including a remarkable lack of adult cardio- vascular disease. 3. The study of medical problems at altitude had provided a basic physiological description of the two direct altitude-related dis- eases. These are an acute form producing high-altitude pul- monary edema (HAPE) and a chronic form which causes a runaway polycythemia. Anes- thesiological and surgical proce- dures suitable to high altitude had been partially developed and it had been discovered that many drugs have altered action 379 PART XI — HUMAN ADAPTATION TO ENVIRONMENTAL STRESS Figure XI-4 — CHANGES IN OXYGEN CONSUMPTION CAPACITY OF LOWLANDERS UPON UPWARD MIGRATION Population Number Sex and Average Age MaxVO. (I/M STPD in/Kg) % Decrease Low Altitude High Altitude U.S. White Researchers 12 Male 27 50.4 (300 m.) 38.1 (4000 m.) 24.4 English Mountain Climbers 4 Male 32 50.0 (sea level) 39.7 (4000 m.) 20.6 U.S.White Soldiers 24 Male? 40.4 (sea level) 32.1 (4300 m.) 20.5 Peruvian Sailors 10 Male 18-21 39.0 (450 m.) 31.4 (4500 m.) 19.5 U.S. White 6 Male 20 64.2 (300 m.) 46.6 (4000 m.) 27.2 Runners U.S. White 5 Male 15-17 65.2 (300 m.) 49.4 (3100 m.) 25.1 Runners Peruvian Quechua (High Altitude Heritage) 10 Male 22 49.3 (100 m.) 44.5 (4000 m.) 9.7 The table shows the maximum oxygen consumption capacity of people who nor- mally inhabit lowlands (below 1,000 meters) and then the percentage decrease in their ability to consume oxygen upon moving above 3,000 meters. The decreases are striking except in the last category, those who were children of people acclimated to high altitudes. Decrease in oxygen consumption is reflected as a significant loss in work capacity. on men living in the low oxygen pressures found at altitude. The formal publication of results on man's adaptational problems at altitude has been substantial since the beginning of 1968, although since that time few new major research efforts have been launched. Significance of High-Altitude Research on Man The relevance of high-altitude re- search to the 25 million people living above 8,000 feet is obvious because of the multiple health effects. The same is true for those who travel up and down from these altitudes. Less can be said about the problem for the much larger number of people living between 5,000 and S,000 feet, since the effects are more subtle and less well known. Of perhaps much greater impor- tance, the study of human popula- tions living under the drastically re- duced oxygen pressures found at high terrestrial altitudes can provide data of major importance for both such basic scientific problems as the mech- anisms of human evolution and such applied problems as the causes of cardiovascular disease. For this rea- son, scientists from practically every discipline involved in the study of man have been concerned with high- altitude research. While it may, therefore, be suggested that research on man at altitude is needed because it may help us discover cures for adult cardiovascular disease or im- prove the health of a significant seg- ment of the world's population, the major scientific justification is the use of the environmental contrast as a research tool. Research Recommendations At the 1967 WHO-PAHO-IBP Meeting of Investigators on Popu- lation Biology of Altitude, a detailed set of research recommendations was developed. These needs have not been met. The following research therefore remains of priority interest: Physiological Adaptation and Ac- climatization to Altitude Introduc- tion — Several studies have indicated that there are important differences in a variety of structural and func- 380 ADAPTATION TO I liTUDE tional characteristics among people who can be identified as: (a) high- landers for many generations; (b) lowlanders acclimatized to altitude; (c) new arrivals at altitude; (d) high- landers acclimatized to sea level; and (e) lowlanders. It is not clear what these differences mean. We do not know, for example, whether these differences reflect sim- ple adaptations to a new environment or are the result of selective adaptive processes or even, in some instances, are detrimental to the individual. For the people who now live at high altitude, and for those who will move there, the most important area of altitude physiology is that which has to do with natural and acquired acclimatization. Study of these proc- esses should direct particular atten- tion to the functional adaptation of people of both sexes, of all ages, and of those living under different work- ing conditions. Of lesser importance to human populations as a whole is the study of the acute adaptive mechanisms, which are of concern to the much smaller groups of people moving be- tween high and low altitude and for whom residence at high altitude is usually brief. Physiology of Exercise and Work Capacity at Altitude — A number of human populations at various levels of altitude have for many generations lived and worked while exposed to low levels of ambient oxygen content, although they have not necessarily been exposed to continued tissue hypoxia. The physical performance capacity of these populations is not adequately established. Studies were suggested on: the basic work capacity of highlanders; the maximum oxygen consumption of altitude populations; the metabolic response to work in various high- lander populations (see Figure XI-5); the effect of age and sex on work capacity in altitude populations; the relationship between heart rate and oxygen consumption in indigenous highlanders. Altitude Limits for Acclimatiza- tion — There is a need to specify altitude tolerance limits for human and other animal species. The tem- poral maintenance of normal func- tional integrity of organ systems, be- havioral activity, and physical and mental performance should be eval- uated. Environmental Factors - are needed to determine the si cance of environmental factors other than hypoxia in altitude acclimatiza- tion such as the climatic conditions and the socio-economic environment. Respiration — An important adap- tation of the resident to altitude, which is different from the lowlander, is his pulmonary ventilatory response to different concentrations of both Figure XI-5 — OXYGEN CONSUMPTION CAPACITY AMONG HIGH-ALTITUDE NATIVES Population Location and Altitude Number Sex and Average Age Max V0- (l/Min/Kg) STP.D. Quechua Peasants Nunoa, Peru 4000 m. 25 Male 25 49.1 University Students "White" Puno, Peru 3800 m. 13 Male 23.5 42.8 University Students "Quechua" Puno, Peru 3800 m. 10 Male 23.8 46.8 Trained Quechua Puno, Peru 4000 m. 9 Male 21.1 48.2 Quechua IViiners Morococha, Peru 4540 m. ? Male 7 51.2 Aymara Natives Chile 3500-3650 m. Male 18.0 49.1 Sherpa Natives Nepal 3400 m. 6 Male 17.8 51.9 Aymara Natives Chile 3500-3650 m. Male 25.6 45.4 Sherpa Natives Nepal 3400 m. 11 Male 24.6 50.4 Aymara Natives Chile 3500-3650 m. Male 34.8 46.3 Sherpa Natives Nepal 3400 m. Male 34.0 47.4 Aymara Natives Chile 3500-3650 m. Male 44.8 44.0 Sherpa Natives Nepal 3400 m. Male 43.6 43.8 The maximum oxygen consumption capacity of native highlanders at high altitudes is comparable to that of native lowlanders at low altitudes (see Figure XI— 4). Thus, the work capacity of the two groups is similar in their native habitats, although lowlanders are at a disadvantage when they migrate to high levels. 381 PART XI — HUMAN ADAPTATION TO ENVIRONMENTAL STRESS oxygen (Oj) and carbon dioxide (COj) in the air he breathes. The native highlander is relatively less sensitive to low levels of O- in alveo- lar air than is the lowlander; it is not clear whether this decrease in sensi- tivity is an advantage or a disadvan- tage at altitude. Analysis of the important adaptive respiratory process should include study of: age and sex differences, neurological factors, acid-base fac- tors, chemoreceptor sensitivity and thresholds, as well as tissue responses to hypoxia. In addition, it would be of importance fo study regulation of ventilation during the performance of physical work at altitude and dur- ing sleep. Sleep and associated peri- odic hypoventilization, as well as performance of hard exercise, in- crease hypoxic exposure. Circulatory Mechanisms of Alti- tude Acclimatization — Although cir- culatory responses in man at altitude have received more study than other physiological responses, we do not know the criteria upon which we could advise healthy people whether they should or should not live at high altitude, or at what stage of mor- phological or functional alterations they should move to low altitude. The following areas of investigation are of importance in answering this problem: 1. Epidemiology: Much needs to be known about the prevalence and incidence of cardiovascular disease at altitude. Ecological factors other than altitude should be identified which af- fect normal cardiac function in highlanders. In addition, we do not know the circulatory response to physical work at different ages. 2. Cardiac Muscle Metabolism: The basic inability of cardiac muscle to work under anaerobic conditions makes it vulnerable to hypoxia induced by high work loads at altitude. Before optimal and maximal levels for work at altitude could be rec- ommended, further studies are necessary on coronary blood flow and cardiac muscle metab- olism during work and rest at altitude. 3. Microcirculation: Whether in- creased capillarity and anasto- motic vascularity in cardiac or skeletal muscle is an anatomical feature of the acclimatization process needs further study. The possible role of changes in the microcirculation in the development of chronic moun- tain sickness has not been de- termined. 4. Pulmonary Hypertension: Lon- gitudinal observations are needed in highlanders who de- velop pulmonary hypertension and right heart hypertrophy. Control measurements are needed that cover both sexes and a wide age range. Special study is needed of the factors that lead to high-altitude pul- monary edema. 5. Circulation Dynamics: More information is needed on the expected changes in cardiac dy- namics at altitude. Included under this heading are observa- tions on cardiac output, car- diac work, peripheral resistance, heart rate, stroke volume, blood pressure as well as the role of changes in blood volume, hematocrit levels, and pulmo- nary circulation. Partitioning of blood flow through vital organs under various condi- tions at altitude is also an im- portant area to be studied. Cellular and Tissue Mechanism of Altitude Acclimatization — The bi- ochemical mechanisms underlying high-altitude acclimatization are in- adequately understood. Respiratory and vascular adaptations to altitude that permit an adequate delivery of O- and removal of metabolites at the cellular level during rest may not be adequate for sustained hard work by healthy men or, for that matter, sedentary life in the elderly and infirm. There is a need to determine the adaptive processes at the cellular level in the highlander as well as in newcomers to altitude. We need to know what role is played in these cellular responses by changes in the amount of myoglobin, the number of mitochondria, and the capacity of the cytochrome and elec- tron transporting system. More in- formation is needed on possible adap- tive increases in enzymes favoring both aerobic and anaerobic metabo- lism. We need to know the degree to which rate-limiting neurohumoral- endocrine mediators affect these cel- lular functions. And finally, we need to know whether genetic factors are operative in the adaptation at the cellular and subcellular level. Other Areas of Altitude Physiology Requiring Further Study — Available knowledge is inadequate concerning nutritional requirements of those with natural or acquired acclimatiza- tion or in those acutely exposed to altitude. Further nutritional and metabolic studies are necessary to establish optimal nutritional allow- ance for high-altitude residents and for those who wish to reside at al- titude. The factors regulating redistribu- tion of fluid and electrolytes among the various fluid compartments need further elaboration. In the long-time resident at altitude we need to know more about the possible role of adaptive tissue and vascular responses in the aging proc- ess. It is also possible that high- altitude residence has an effect on man's immunological responses and on the types and frequency of in- fections that he harbors. The sequential changes that occur during the period of adaptation of the newcomer to high altitude are 382 ADAPTAT1' [GH ALTITUDE poorly understood. Accurate time- tables are not available that show rate of adjustment for each organ system including the respiratory, cardiovascular, digestive, endocrine, renal, and neuromuscular systems. The time course of the de-acclimat- ization process should also be studied, particularly in those who are exposed intermittently to altitude. The working group suggested that a handbook of physiological values be developed which uses standardized terminology. A collection of data on normal and abnormal biological values for different altitudes is ur- gently needed. Human Biology at High Altitudes The working group considered the problems posed by the biology of human populations living at high al- titudes, which could also, and equally importantly, be relevant to many fundamental problems of human bi- ology in general. It seems appropriate to present the recommendations for these two approaches separately, although in practice the methods used and ob- servations made will be closely sim- ilar. The Characterization of High- Altitude Populations — Using com- positive methods of approach and standardized procedures, information should be obtained in the following categories: 1. Fertility and the Components of Fertility: (a) by demographic methods; (b) by methods used in the reproductive physiology of man and of animals, which could be applied to human pop- ulation studies. 2. Growth, Development, and Ag- ing: With a focus on age changes and variability in char- acteristics thought to be (a) of adaptive value at high altitude; and (b) related to the somatic fitness of individuals. Such studies should not be divorced from the psychological and in- tellectual changes that occur during development. 3. Nutrition: In all cases, the nutritional assessment of the populations studied should be made in as detailed a manner as possible, commensurate with the resources available. Such assessments should include: (a) the nutritional status of indi- viduals; (b) detailed nutritional surveys, where possible; and (c) biochemical studies related to nutrition. 4. Special Problems Relating to Work Capacity: Both physio- logical and psychological meth- ods should be used. 5. Epidemiology: In all cases, the pattern of disease distribution in populations should be stud- ied. Where additional demo- graphic information is available, it is highly important that more vigorous epidemiological stud- ies should be made. It is of great importance that demo- graphic methods should be de- veloped which would enable the relationships between age, disease, and morbidity to be ascertained. 6. Genetics: Further information is required on: (a) the distri- bution of polymorphic systems in high-altitude populations; (b) the heritability of quantita- tive varying traits, particularly those presumed to be adaptive in nature; and (c) congenital defects, especially those pre- sumed to have a genetic com- ponent. All these studies must include as precise as possible an analysis of all biological and physical aspects of the environment. (See, for e> ure XI-6) Adequate precautions must be taken to insure statistical repre- sentation and control situations, which will often mean the study of lowland populations. And finally, the demographic background of the pop- ulations under study must be ascer- tained in as great a detail as possible. Altitude Studies in General Human Biology — The ecological situations of high-altitude populations often af- ford unique opportunities for the study of fundamental human biology. In particular, the following problem areas can be investigated: 1. Developmental Flexibility: The determination of the magni- tude and biological significance of normal environmentally in- duced responses. 2. Genetic Structure of Human Populations: Isolated groups, where it may be presumed that factors such as genetic drift may be operative, are partic- ularly important objects of study. Problems involving gene flow and the effects of selective migration may also be encom- passed. 3. Natural Selection: Of the vari- ety of ways by which the prob- lem of detecting natural selec- tion may be approached, it was thought that particular atten- tion should be devoted to the analysis of the comparative fer- tility and mortality of different phenotypes and, where pos- sible, genotypes. Such investi- gation could be made most appropriately in both stable high-altitude populations and in those which have recently changed their altitude. These three topics deal with funda- mental problems of human biology and thus conflict with the objectives of categorizing the biology of high- altitude population, as discussed 383 PART \I — HUMAN ADAPTATION TO ENVIRONMENTAL STRESS 8 - 7 - 6 - 5 - ■1 3 - 2 - 1 - 0 - 7p 6 - 5 - Figure XI-6 — GROWTH RATE DIFFERENCES BETWEEN NUNOA AND U.S. CHILDREN MALES Nuni-,.1 FEMALES us ..Nunoa 4 \ \,^_ 3 - \ 2 - V 1 0 - 1 1 1 1 1 1 1 '"'•.. .. 1 2 4 6 8 10 12 14 16 18 20 2 2 Age (years) The graph shows differences in rates of general body growth between Nunoa and U.S. children. The Nunoa children are primarily of Indian derivation and live in an area of about 1.600 square kilometers whose minimum altitude is 4.000 meters and whose maximum altitude is above 5,500 meters. The Nunoa children have a slower rate of general body growth than is standard in the U.S., but their growth rate continues over a longer period of time. earlier. However, their study de- mands a large-scale multidisciplinary approach in selected areas, in which the various characteristics itemized earlier would still have to be subjects. Health Aspects of Altitude Ischemic Heart Disease at High Altitude — There is evidence that the incidence of ischemic heart disease in high-altitude populations is lower than at sea level. Experimental stud- ies indicated increased resistance to myocardial necrosis in altitude-accli- matized animals. A controlled epi- demiological study of the incidence of ischemic heart disease in high- altitude populations will be carried out using suitable sea-level controls and standardized techniques of in- vestigation. Risk factors for ischemic heart disease will be evaluated and correlated with necropsy data. Adap- tive mechanism of the heart to high altitude pertinent to acute cardiac necrosis will be examined in experi- mental animals. Careful investigative techniques of population analysis will be employed and, depending on initial results, preventive trials may be initiated. Development of Prognostic Tests for Altitude Sickness — It is impor- tant to be able to identify individuals who are likely to develop acute or chronic mountain sickness or high- altitude pulmonary edema. Simple laboratory methods for determining the sensitivity of the carotid body and respiratory responses to various stimuli including hypoxia should be devised. Other screening tests should be evaluated on sea-level subjects who will later be exposed to high altitude. Epidemiology, Therapy, and Pre- vention of High-Altitude Pulmonary Edema — By means of questionnaires and interviews, the importance of factors such as reascent, length of stay at sea level, and slow ascent upon the occurrence of HAPE will be assessed. Field trials of prophy- lactic drugs, using a double-blind technique, will be carried out, prefer- ably in troops. In selected patients during the acute stage the hemody- namic effect of selected drugs will be investigated. Ventilation-perfusion characteristics will be examined se- quentially in the acute stage and dur- ing recovery. Congenital Malformations of the Newborn at High Altitudes — Pre- liminary studies have shown that the incidence of congenital abnor- malities of the heart and other struc- tures is increased at high altitude. Whether this is a genetic abnormality or due to maternal hypoxia at a criti- cal stage of fetal development is not known. Since maternal hypoxia can be prevented or minimized, studies at high altitude are indicated. The causative factors can be evaluated by employing a standard, highly objec- tive method of examination in a prospective study of newborn infants and schoolchildren at selected levels of altitude in different countries. Countries to be included are those where the appropriate facilities are available. The administration of ox- ygen to newborns should be carried out at high altitude with suitable controls to determine its late effect on the incidence of PDA and the cardiovascular system. 384 ADAPTATION T HIGH ALTITUDE High-Altitude Medicine — Despite the fact that over 25 million people live at high altitudes, no information regarding their special medical prob- lems is available. The following sub- jects need to be treated: (a) high- altitude diseases such as acute and chronic mountain sickness and high- altitude pulmonary edema; (b) mod- ification by high altitude of diseases that are common at sea level such as pneumonia, coronary disease, and shock; (c) action of drugs such as opiates and anesthetics that are modi- fied by high altitude; (d) occupa- tional diseases at high altitudes. The emphasis should be on clinical medi- cine rather than physiology. Evaluation of the Effects of Pul- monary and Cardiac Disease upon Cardio-Respiratory Function at High Altitude — Pulmonary function and hemodynamic studies should be car- ried out in high-altitude residents with silicosis, stanniosis, and follow- ing pneumonectomy. The working capacity of such patients should be evaluated by appropriate methods. Techniques of early detection of in- dustrial pulmonary disease at high altitude should be evaluated and ap- plied to workers. Factors Affecting Biliary Cholelithi- asis in Native Highlanders — Choles- terol stones are commonly observed at high altitude, with probably a different sex incidence than usually observed at sea level. Since this is an important cause of illness, the causative factors should be studied. The study should include an inves- tigation of dietary habits and serum lipids of patients with proven chole- lithiasis compared to control subjects living in the same area with normal cholecystograms. Drug Action at Different Alti- tudes — Drug action is probably sig- nificantly modified in the hypoxic high-altitude environment. Toxicity may be enhanced or diminished and the therapeutic effect may be altered. Studies should be made and known information collected regarding the effect of selected drugs at various altitudes in the world. Drug' as narcotics, anesthetics, analgesics, opiates, pressor drugs, and cardiac glycosides should be investigated. Vital Statistics in Relation to Al- titude — Vital statistics of WHO are arranged for countries according to many categories — but not altitude. Such information is necessary in order to determine the effect of al- titude upon the incidence of disease and mortality. Functional and Intellectual Cor- relates of Altitude Hypoxia in Chil- dren — It is important to determine if the development and function of the central nervous system is ad- versely affected by the chronic hy- poxia of high altitude. Suitable physiologic tests should be developed to quickly determine the degree of chronic hypoxia in children. Tests of central nervous system functions that could be affected by chronic hypoxia should be designed that would be suitable for field studies. ADAPTATION TO SMOG AND CARBON MONOXIDE Smog is a vaguely defined word, certainly not a well-defined chemical species. In general, it means the totality of community air pollution, though it has been applied more specifically (a) to sulfur oxide and particulate pollution, occurring chiefly in coal-burning areas, and (b) to photochemical air pollution, common in southern California, which is af- fecting an increasing number of ur- ban cities with intense pollution from motor-vehicle exhaust. Smog in southern California has not been shown capable of increasing the short-term fatality rate, but both types of community air pollution cause respiratory irritation, both can aggravate asthma (though they prob- ably do not cause it), and both are suspected of a part in the develop- ment of chronic respiratory disabil- ity — emphysema in the case of photochemical pollution, and chronic bronchitis in the case of sulfur oxide and particulate pollution. Readily measurable impairment in airway resistance and other respiratory func- tions occurs among the populations most likely to show increased fre- quencies of chronic bronchitis and emphysema. The distinction between the two diseases as causes of death is largely related to the extent to which there are adaptive mechanisms in the airways causing increased se- cretion of mucus. Man is exposed to carbon mon- oxide (a) in cigarette smoking, (b) in occupational exposures to com- bustion products, (c) in connection with community air pollution, (d) in confined areas contaminated by motor-vehicle exhaust, and (e) when household cooking and heating ap- pliances are not adequately vented. Carbon monoxide can and does kill, especially in association with occupa- tional exposure and poorly vented appliances. There is growing suspi- cion that the excess mortality from coronary heart disease among ciga- rette smokers may be due to carbon monoxide, a major toxic constituent of cigarette smoke. (See Figure XI-7) There is also a suspicion that carbon monoxide, as a community air pollu- tant, may interfere with the survival of patients with acute myocardial in- farction (heart attacks), and that it may play a role in impairing the op- eration of motor vehicles. 385 PART XI — HUMAN ADAPTATION TO ENVIRONMENTAL STRESS Figure XI-7 — POSSIBLE EPIDEMIOLOGICAL AND PATHOPHYSIOLOGICAL MECHANISMS RELATING CARBON MONOXIDE AND MYOCARDIAL INFARCTION Cigarette Smoking Domestic (?Seasonal)" Ambient Pollution _. CARBON MONOXIDE . "* EXPOSURE -Occupation ■ Emphysema - ->(Pulmonary Diffusion) I j ^ Carboxyhemoglobin >0xygen Delivery Rate ♦ Y„ Y2, . . Y„ -> Hematopoesis Blood Viscosity Heme Catabolism '(Hgb, Catalase, etc.) Carboxymyoglobin Oxyhemoglobin Dissociation Myocardial Atherosclerosis Metabolism Cardiac Work X,, X„ . . X„ Thrombo-embolism Myocardial Infarction ^_ Fatal Myocardial Infarction The figure shows, on the right-hand side, possible biochemical and physiological mechanisms and, on the left-hand side, possible epidemiological associations. Solid arrows indicate an increase; open arrows, a decrease or impairment of the mechanism. This scheme is qualitative and some of the reactions shown may be of insignificant magnitude. Testable hypotheses relating carbon monoxide and myocardial infarction from a clinical and mechanistic view are numerous, but testable hypotheses relevant to the epidemiological approach are few. And yet an investigation of the epidemio- logical approach would produce observations on biological and physiological processes as well as studies of disease frequency. Scientific opinion increasingly tends to the view that air-pollutant expo- sures, whether smog or carbon mon- oxide, do not generally cause a specific disease, but rather that they contrib- ute to the aggravation, and possibly to the causes, of several possible dis- eases. In an excessively simplistic way, the main target organ for smog is the respiratory system. The main target organ for carbon monoxide is the circulatory system, with the cen- tral nervous system being a secondary target. The human processes of adapting to these agents produce alterations in function and may also be the same mechanisms that lead to their con- tributions to chronic disease and dis- ability. Should this suspicion be borne out by research over the next five to ten years, the likelihood of a substantial reduction in two very common classes of chronic disease would be greatly advanced. Since heart disease accounts for about 20 percent and chronic respiratory dis- ease for about 2.5 percent of all deaths in California from 1965 through 1967, even a small diminu- tion in the burden attributable to them from adaptive reactions would be well worthwhile. Present Scientific Data Base One major piece of evidence re- lating the finding of symptoms of persistent cough and sputum and impairment of respiratory function with the likelihood of developing chronic respiratory disease is a study by Gregg, a general practitioner, of patients in a relatively unpolluted sector of London. Cigarette smokers in his practice who had persistent cough and sputum when first ex- amined had a more rapid deteriora- tion of pulmonary function during the ensuing five years and also a lower initial function than persons with a similar smoking history but no symptoms. In the case of carbon monoxide exposures, the much higher frequencies of coronary heart disease among cigarette smokers suggest a re- lationship between carbon monoxide exposures and the chronic diseases associated with lipid deposition in the main blood vessels. So, too, does the demonstration by Astrup in Den- mark that, among persons with well- advanced atherosclerotic disease who were smokers, there were much higher levels of carboxyhemoglobin than among those with similar smok- ing histories but who did not have atherosclerosis. Recent findings may help to iden- tify those individuals in a population who are susceptible to the chronic diseases associated with maladapta- tion to inhaled pollutants. These in- 386 ADAPTATION TO 5MOG AND CAR15' s^ MONOXIDE elude, in particular, the demonstra- tion that a diminution in trypsin inhibitor in the serum (the so-called alphai anti-trypsin deficiency syn- drome) predisposes individuals who were homozygotically deficient to the early onset of pulmonary emphy- sema. Such individuals are infre- quent in the population; studies so far report finding only about one in 3,000. However, it is not yet known whether /zeferozygotically deficient individuals (who may comprise 5 to 15 percent of the general population) are also more prone to chronic res- piratory irritants. In a few pilot studies, heterozygotically deficient in- dividuals who were also cigarette smokers showed evidence of chronic respiratory disease in a very high proportion, namely 31 out of 33. Needed Scientific Activity — Adap- tation to carbon monoxide involves, to a substantial degree, the study of populations of cigarette smokers, since their exposures to this agent are very common and of substantial magnitude — that is, sufficient to in- activate from 5 to 15 percent of the oxygen-carrying capacity of the blood for moderately heavy smokers who inhale. Similarly, there is evidence that cigarette smoking increases the risk of chronic respiratory conditions and respiratory impairment in per- sons exposed both to the sulfur oxide and particulate type of pollution and to photochemical smog. (See Figure XI-8) Thus, we are unable to speak logically of the epidemiologic aspects of studying human adaptation to car- bon monoxide and to smog without considering cigarette smoking. Beyond this, however, we must also consider occupational exposures and relevant and related exposures that occur in the home and during recreation and transportation. While there are large numbers of human subjects exposed to both carbon mon- oxide and smog, a longitudinal study, necessary to obtain the best type of data for the study of adaptation, has rarely been undertaken for either of them. In the case of occupational exposure to carbon monoxide, some longitudinal data have been obtained; there are, however, few longitudinal data in the case of carbon monoxide associated with cigarette smoking, since the importance of this exposure has been appreciated only since 1960. In the case of smog, there are popu- lations occupationally exposed to two of the major ingredients that have toxic properties — namely, ozone and nitrogen dioxide — but results of the study of occupational groups are not sufficiently clear-cut for an evalua- tion of adaptation. Short-term adaptive mechanisms have a more abundant data base. There is a small data base from ex- perimental human studies, and a somewhat larger one from experi- mental animal studies, of adaptive mechanisms for ozone and nitrogen dioxide exposures. Data for carbon monoxide are more abundant, but for neither is the data set adequate. Limitations — The data base for studying adaptation to these agents is unfortunately impaired by the view of one sector of the scientific community that adaptation is solely a beneficial process, one that does not carry with it the risks of the long- term consequences suggested above. Thus, a number of scientific papers have cited the ability of patients to increase the oxygen transport in re- sponse to carbon monoxide exposure as evidence that community or ciga- rette-smoking exposures to carbon monoxide are of little consequence to health. Recent Scientific Findings Impairment of Respiratory Func- tion — It has been demonstrated that nitrogen dioxide, a major product of photochemical smog, is an effective agent for producing emphysema in experimental animals when exposures Figure XI-8 — RATES OF CHRONIC BRONCHITIS AND EMPHYSEMA FOR SMOKERS AND NON-SMOKERS 21 AND OVER PRESENT SMOKERS BY NUMBER OF CIGARETTES SMOKED PER DAY —HEAVIEST AMOUNT The diagram shows the substantial contribution of cigarette smoking to chronic respiratory conditions. Heavy smokers have as much as five times the excess morbidity of non-smokers. For females this excess is even greater than for males. The rates are adjusted for age and include data on subjects 17 years of age and over. 387 PART \I — HUMAN ADAPTATION TO ENVIRONMENTAL STRESS are long term and at concentrations as low as from 0.8 to 4 parts per million. The work has been reported by Freeman and his colleagues and has been demonstrated in rabbits, rats, mice, and monkeys. Closely related is the finding of Mueller, Buell, and Thomas, at the California State Department of Public Health, that structural changes in proteins can be produced by ex- posures to low levels (0.25 to 5 ppm) of either nitrogen dioxide or ozone for a short period of time, and that these changes revert slowly. The mast cells reversibly disappear from the respiratory airways on exposure to nitrogen dioxide; nitrogen dioxide and ozone inhalation can lead to lipid peroxidation in the pulmonary parenchyma. These changes are all presumably adaptive in nature, but their consequences for long-term ef- fects are certainly suggestive, since lipid peroxidation has also been as- sociated with the aging processes. Balchum, Armstrong, and Ury have reported the impairment of respira- tory function in persons already hav- ing chronic respiratory diseases who were exposed to elevated levels of photochemical smog occurring in Los Angeles. The lung-function test most consistently responding was that of airway resistance, and its increase reflects the likelihood that persons with chronic respiratory diseases would have to expend more energy to ventilate their lungs during smoggy periods than during normal ones. Toyama in Japan and Holland, Douglas, Waller, and Lunn in Eng- land have shown that schoolchildren exposed to pollution, mostly in the forms of sulfur oxide and particu- lates, have impaired respiratory func- tion during periods in which the pol- lution is elevated and have a greater frequency of respiratory conditions. The finding, which has been con- firmed in Italy, should also be studied in other countries. It seems quite reasonable to assume that these changes in schoolchildren represent adaptation, and with it the risk of developing chronic respiratory dis- ease. At a meeting in Geneva in 1969 of the Directors of Cooperating Laboratories of the World Health Organization's International Refer- ence Center on Air Pollution, the recommendation was adopted that first priority for additional compara- tive epidemiologic studies in air pol- lution should be given to studies of the effects of air pollution on school- children. Impairment of Circulatory Func- tion — Astrup has shown that the ex- posure of rabbits on a high-choles- terol diet to increasing amounts of carbon monoxide will increase the atherosclerotic changes in the large blood vessels. Similar changes can be produced by placing the animals in a chamber with low oxygen ten- sion. The findings that smokers with atherosclerosis have higher levels of carboxyhemoglobin, implying higher or more intense exposures to carbon monoxide or greater retention from smoking, than do individuals with similar smoking histories but without atherosclerosis, is strongly suggestive of the role of carbon monoxide in this process. Yet human populations at high altitude, where the oxygen ten- sion is low, have a lower frequency of atherosclerosis, lower blood pressure, and lower cholesterol. Accordingly, it has been most valuable to have an experimental comparison of the ef- fects of high altitude and of repeated carbon monoxide exposures in healthy experimental subjects reported by Astrup and Pauli. They studied eight subjects divided into two groups of four; each group was exposed both to sufficient carbon monoxide to produce 15 percent car- boxyhemoglobin and to altitude at 11,225 feet (roughly equivalent in terms of oxygen saturation). The major findings were that with car- to.ryhemoglobin exposure, the oxy- hemoglobin saturation curve shifted to the left (i.e., the available oxygen would be given off less readily at the tissue level under these circum- stances), whereas with altitude the curve shifted to the right (i.e., the hemoglobin would more readily give up its oxygen at the tissue level). Carboxyhemoglobin exposures did not increase the respiratory rate, but altitude did. Both types of exposure increased the rapidity with which new red blood cells were produced. Both types of exposure, if sufficiently intense and prolonged, are capable of leading to an increase in the hematocrit. Thus, the major differ- ence in adaptation to altitude and roughly equivalent carboxyhemoglo- bin levels produced by exposure to this agent is that men adapt to changes in oxygen delivery in the case of altitude; in the case of carbon monoxide exposures, the changes that occur in oxygen delivery appear to be maladaptive. There is a res- piratory volume compensation for decreased oxygen-carrying capacity in the case of altitude, but there is none for carbon monoxide. Ayres, among others, has shown that different portions of the circula- tory system have different ways of adapting to the impairment of oxygen transport produced by carbon mon- oxide exposures. (See Figure XI-9) In particular, the myocardin adapts to increased demand of the heart by increasing the blood flow, since its oxygen-extraction ratio is usually much higher than other tissues. That is to say, the heart normally takes out of the blood that circulates through it a high fraction of the available oxygen in relation to the pattern for other organs. Hence, im- pairment in oxygen delivery by car- bon monoxide requires an increase in the blood flow through the heart muscle. In the case of people with coronary heart disease, however, there is no way in which the heart can increase its blood flow. Thus, according to Ayres' data, it is demon- strable that in persons with coronary heart disease, carbon monoxide dras- tically interferes with the metabolism of the heart muscle, shifting it from an oxidative to a less efficient form 388 ADAPTATION TO SMOG AND CARBON MONOXIDE Figure XI-9 — HEMODYNAMIC AND RESPIRATORY RESPONSES OF FIVE NORMAL SUBJECTS TO CARBOXYHEMOGLOBIN (COH. ) Subj. COHb (% sat) Pressure (mm-Hg) Ar-ven diff (% by vol.) Cardiac output (lit./ min) Vent (liter) CO, (mm-Hg) LA (wedge) PA (mean) Arfo2 Ven fo2 1 10.48 1 8.84 28 28 9 9 89 81 45 42 3.40 3.82 5.23 4.46 4.23 4.23 34 1 36 [ 2 j 6.29 86 80 37 30 3.96 4.55 4.37 4.35 4.68 5.72 36 1 36 [ 3 I 3 3 14 12 74 68 42 37 3.92 4.24 4.31 4.17 2.55 3.11 36) 40 f 4 10.37 | 4.95 9 9 13 13 84 79 49 42 4.00 4.66 5.32 6.54 5.43 7.36 39 1 38 ( 5 10.96 | 9.69 7 11 12 18 77 72 41 35 4.02 4.81 6.00 4.68 4.87 4.24 36 1 39 ( The table shows that the oxygen tensions of arterial and mixed-venous bloods decreased between 7.3 and 13.3 percent, respectively, when the carboxy- hemoglobin rose to between 4.95 and 9.69 percent of saturation. Cardiac output, oxygen consumption, and body-surface ventilation per minute did not change consistently, but the difference in arterial and venous blood, reflecting extraction of oxygen by tissue increased in all five subjects. In the one patient who received the greatest amount of carbon monoxide, left arterial pressure rose and cardiac output fell, indicating abnormal left ventricular function. These studies show that small amounts of carboxyhemoglobin do indeed decrease oxygen tension in the blood which in turn may cause other problems related to the supply of blood throughout the body. The first line of each set of data shows value before breathing CO at 0.4 percent in air; the second after breathing. Abbreviations are: sat, saturation; LA, left atrium; PA, pulmonary artery; AR, arterial; t,, , oxygen tension; Ven, mixed venous; Ar-ven diff, arterial-venous difference; Vent, ventilation per square meter of body-surface area per minute; tco , carbon-dioxide tension. of metabolism. Such individuals can- not adapt efficiently to carbon mon- oxide exposures. r'ermutt and Farhi have worked out a theoretical example of the compen- sations needed to maintain tissue oxygenation in the presence of 9 percent carboxyhemoglobin, which would correspond to a continuous exposure of a normal subject at sea level for several hours to carbon monoxide (CO) at 70 parts per mil- lion. Such a CO hemoglobin satura- tion would have an effect equivalent to that found with a 23 to 46 percent decrease in the oxygen pressure available for supplying the needs of the body, and a 13 to 37 percent decrease in blood flow or decrease in the amount of circulating hemo- globin. In order to compensate for this amount of COHb, an increase of from 19 to 39 percent in blood flow would be required. This analysis has forcefully driven home the high physiologic cost of adapting to car- bon monoxide. The Risks of Long-Term Expo- sures — Long-term exposures of an- imals, particularly small rodents, have shown that ozone will increase pul- monary fibrosis, just as long-term exposure of other animals will in- crease pulmonary emphysema. It has also been shown by Stokinger and his colleagues that the exposure of experimental animals to brief, low levels of ozone protects them from subsequent high-level exposure which would otherwise be fatal. This is doubtless a useful adaptive mech- anism, but its cost may be to increase the risk of chronic respiratory dis- ease. Stokinger and his group have also shown cross-tolerance between ozone and other oxidants. However, tolerance in man has not been dem- onstrated. Bennett has reported on long-term exposures of small numbers of hu- man subjects to 0.5 parts per million 389 PART XI — HUMAN ADAPTATION TO ENVIRONMENTAL STRESS of ozone, 3 hours a day, 6 days a week, for 12 weeks. The individuals so exposed had a gradual decrease in the forced expiratory volume in one second which began to occur after 8 weeks of exposure and con- tinued to be depressed for 8 weeks after the termination of exposure. A lower dose failed to produce this effect. Prevailing Controversy and Needed Research Cohen, Deane, and Goldsmith, utilizing data obtained for other pur- poses, studied the possible effect of carbon monoxide exposure on the case fatality rate among persons ad- mitted to Los Angeles hospitals with myocardial infarction. They showed that the rate increased during the high pollution period and in the higher of the two pollution areas of Los Angeles County. Without addi- tional studies, however, they were reluctant to attribute this increase only to carbon monoxide. Contro- versy also exists concerning the effect of carbon monoxide on the central nervous system and, hence, its pos- sible role in the performance of com- plex tasks requiring accurate time evaluation, such as driving an auto- mobile. There has been no decisive evidence concerning the role of car- bon monoxide in general in motor- vehicle accident frequency. The interaction of the various com- ponents of both forms of smog in producing health effects remains con- troversial. Of particular interest is the hypothesis recently put forward by Pitts, among others, that one of the essential mechanisms in the early oxidation of nitric oxide to nitrogen dioxide is the absorption of energy by atmospheric oxygen and conver- sion of some of the normal triplet oxygen to a singlet delta form that may have a finite half-life and could be of biological importance. A cross-sectional study of the fre- quency of emphysema in several cities in relation to the history of smoking and of pollution exposure is going to be necessary in order to resolve some of the questions about the effects of smog on chronic respiratory disease. The identification of active atmospheric species produced by photochemical processes is an im- portant one that may have powerful interactions with radiological health and carcinogenesis. Closely related is the possibility that agents in photo- chemical smog may be mutagenic or teratogenic, though such reactions would scarcely be considered adap- tive ones. Relationship to Environmental Management It is clear that community exposure to carbon monoxide would be sub- stantially diminished if automobiles in operation were decreased either in number or in the amount of car- bon monoxide that they emit. Re- duction in emissions of hydrocarbons and oxides of nitrogen should also have a substantial effect on the in- tensity of photochemical smog, al- though the effect will take a number of years to be fully evident. Since 1956, the United Kingdom has greatly reduced the amount of par- ticulate matter in many of its urban areas, and since 1967 there has been a pronounced decrease in sulfur oxide and particulate emissions in coastal cities of eastern United States. Stud- ies by Fletcher and his colleagues have shown that, in parallel with the decrease in particulate matter in Lon- don, there has been a decrease in the frequency of chronic bronchitis and in the amount of sputum pro- duced by groups of people who had comparable smoking exposures all during this period. The attention paid to atmospheric pollutants is responsive largely to public concern with air pollution as a menacing and offensive substance. The public has not felt it necessary to know the precise health effects. The possibility exists, therefore, that some questions that are of great sci- entific importance will never be an- swered, since it is hoped that the increasingly vigorous control meas- ures advocated by the Environmental Protection Agency will reduce com- munity exposures and thus make some of the longitudinal studies un- likely to reflect present or increased exposures. Thus, the greatest priority should be given to the specific exploration of the hypothesis that pollutant ex- posures which lead to impairment of function may also increase the risk of developing chronic cardiac and respiratory disease through the mech- anisms of adaptation which they pro- voke. Longitudinal research on ex- posed populations and their adaptive mechanisms has been inadequately supported because of the difficulty of assembling teams of competent in- vestigators over the longer periods of time necessary for this sort of re- search. From two to ten research groups, some of which are not in the United States, will be needed to plan and carry out longitudinal studies to evaluate the adaptation of human subjects to smog and to car- bon monoxide. 390 APPENDIX SUMMARY AND RECOMMENDATIONS Reprinted from the Third Annual Report of the National Science Board Environmental Science — Challenge for the Seventies (NSB 71-1). Modern civilization has reached the stage where, hence- forth, no new use of technology, no increased demands on the environment for food, for other natural resources, for areas to be used for recreation, or for places to store the debris of civilization, can be undertaken to benefit some groups of indi- viduals without a high risk of injury to others. No environ- mental involvement of man can any longer be regarded as all good or all bad. Problems can be mitigated, but absolute solutions are probably unattainable. The best that can be sought, therefore, is to optimize, to try to achieve the wisest cost-benefit decision for society for each action contemplated. Such a strategy requires a strong base of scientific knowledge and understanding of the environment, ability to predict reli- ably its future course, and, especially, the ability to construct models through systems analysis of the environment and of man's interaction with it on a scale never previously achieved. It is within this perspective that the present status of Environmental Science has been examined. Environmental Science is conceived in this report as the study of all of the systems of air, land, water, energy, and life that surround man. It includes all science directed to the system-level of understanding of the environment, drawing especially on such disciplines as meteorology, geophysics, oceanography, and ecology, and utilizing to the fullest the knowledge and tech- niques developed in such fields as physics, chemistry, biology, mathematics, and engineering. Included, therefore, are such diverse matters as climate, air turbulence, the air-sea interface, estuaries, forests, epidemics, earthquakes, and groundwater. These environmental systems contain the complex processes that must be mastered in the solution of such human problems as the maintenance of renewable resources (water, timber, fish), the conservation of non-renewable resources (fuels, metals, species), reducing the effects of natural disasters (earthquakes, tornadoes, floods), alleviating chronic damage (erosion, drought, subsidence), abating pollution by man (smoke, pesticides, sewage), and coping with natural pollution (allergens, volcanic dust, electromagnetic "noise"). Environmental Science is now exceedingly vigorous, con- sidered in relation to its development over many centuries. Notable advances are being recorded at an accelerating rate New tools and techniques, borrowed from all of science and technology, are being brought to bear on the problems of observation, measurement, and analysis. Across all of environ- mental science there is a heightened awareness of the essential nature of the environment and the directions that scientific effort should take. Nevertheless — and it is the principal con- clusion of this report — Environmental science, today, is unable to match the needs of society for definitive information, pre- dictive capability, and the analysis of environ- mental systems as systems. Because existing data and current theoretical models are inadequate, environmental science remains unable in virtually all areas of application to offer more than qualita- tive interpretations or suggestions of environmental change that may occur in response to specific actions. There are two primary reasons for this state of affairs. One involves the nature of environmental science itself, the other the resources available for its advancement. (1) The natural environment is not a collection of iso- lated events and phenomena, but rather a vast, integral, mutually interacting system. The recent advent of new technology and technique (satellites, advanced computers, instrumentation of many types, and the methods of sys- tems analysis) for the use of environmental science has, indeed for the first time, provided feasibility for attacking the scientific problems that this environmental system presents. The tasks ahead, however, are of unprecedented magnitude and difficulty. (2) The trained scientific manpower available to meet this challenge is extremely limited in each of the essential aspects of environmental science. More serious is the fact that this manpower is spread exceedingly thin, both with respect to the manifold problems presented and to the institutions within which research is conducted, new sci- entists are educated, and scientific results are applied to the solution of problems of the public interest. Indeed, the institutions of environmental science, as here defined, remain in an early stage of development. This situation constitutes a crisis for the Nation. While environmental problems are so diverse and diffused that virtu- ally every activity of civilization interacts with the environ- ment, few persons can be aware of the full scope of challenge that lies ahead. The current mismatch between capability and need is at least comparable to any other challenge to science and technology that was encountered during this century. To meet this situation the National Science Board offers five groups of recommendations: 1. NATIONAL PROGRAM Several factors emphasize the urgency of establishing a national program for advancing the science of environmental systems: (a) New organizations formed at the highest level of the Federal Government, the Council on Environmental Quality and the Environmental Protection Agency, have been charged with responsibilities that include the assessment of the environmental impact of civilized man. These agencies must foresee secondary effects and compare quantitatively the multiple consequences of alternative courses of action. Such efforts are severely limited by the present level of understand- ing of the behavior of environmental systems. They would become progressively more feasible as advances in environ- mental science increase man's predictive power, (b) The use of energy and the processing of material by man are doubling 391 APPENDIX every 14 years.* Correspondingly, the number and severity of environmental problems will increase, while the adequacy of ad hoc piecemeal expedients will decrease, (c) As population grows, and with it the artifacts of civilization, the human and economic losses due to sporadic natural disasters, already great, will increase in scale, (d) At the same time, the intensification of man's needs for both renewable and non-renewable re- sources requires even greater manipulation and mastery of the natural and man-made systems that constitute the environment. It is, therefore, recommended that this urgency be recognized through the early development of a comprehensive national program to expedite the progress of environmental science. The problems with which environmental science must deal, however, do not respect local, State, or even national boundaries. It is thus further recommended that this national program explicitly provide for the essential Federal role in encouraging and supporting the work of environmental sci- ence, quite apart from the role the Federal Government is al- ready exercising with respect to improving and protecting the environment (e.g., programs of soil conservation, sewage treat- ment, air and water pollution control, etc.). Both nationally and in matters of international cooperation the Federal Gov- ernment must assume leadership in fostering scientific advance. This national program should be based on three efforts: (1) Emphasis should be given to projects, manned by coordinate teams, directed to inter- mediate scale or "mesoscale" problems, that is, problems on the scale of lakes and estuaries, urban areas, regional weather systems, and oce- anic fisheries. Advances on this scale will provide immediate benefits to man. (2) At the same time, the program must ensure continued effort on global problems, even though their solution may require the resolution of smaller scale issues. In the long run it is the global con- straints that will shape and delimit the future development of civilization. (3) Finally, the program should ensure the con- tinued vigor of those aspects of disciplinary re- search and graduate education needed to provide the specialists and new knowledge required for environmental science. The remaining recommendations form an important part of the total recommendation of a national program. The entire program should be established at the earliest practicable date, if progress during this decade and its culmination during the following decades are to be commensurate with the urgency now faced. 2. PRIORITIES One of the inescapable conclusions of this report is that the number and complexity of scientific problems, both theo- 'Both activities have shown 5% average annual growth rates for the last 20 years, as reported in Man's Impact on the Global Environment: Assessment and Recommendations tor Action, MIT Press, Cambridge, Mass., 1970. The total consumption of fossil fuel in the United States also grows about 5% per year; the conversion of an increasing fraction of fossil energy to electrical energy leads to a higher annual growth rate in the utilities. retical and experimental, that confront environmental science far exceed the capability of available manpower to attack all of them effectively at the same time. If these resources remain distributed as they are, scattered and fragmented, and if prob- lems to be solved are selected largely on the basis of the per- ceptions of individuals or small isolated groups, progress in environmental science cannot meet the needs of expressed national goals and purposes. Accordingly, it is recommended that early con- sideration be given to strengthening arrangements whereby priorities for environmental science can be set, matched to existing and required scientific and engineering manpower, and changed as cir- cumstances warrant. In setting such priorities ap- propriate weight must be given to the feasibility of achieving scientific solutions in a reasonable time and to the social and economic costs and benefits that could accrue if solutions were attained. 3. ORGANIZATION FOR ENVIRONMENTAL SCIENCE The scope encompassed by the national program, proposed above, the Federal role inherent in this broad effort, and the patent need for establishing priorities raise serious questions of the adequacy of present arrangements within the Federal Government for planning, coordinating, managing, and re- viewing programs of environmental science. As for all science, environmental science today is the responsibility of many agencies, often with conflicting interest under differing agency missions and responsive to many Congressional committees. At the same time the problems to be solved are broader, more difficult, and more dependent upon the coordinated use of scientific resources than those faced in the earlier development of nuclear energy, radar, and space exploration. For these reasons, it is strongly urged that the Federal responsibility for environmental science, and for its promotion, organization, and support, be considered as important as the corresponding but separate responsibility for environmental qual- ity. In particular, arrangements for Federal deci- sionmaking must be especially effective for the following activities: (1) The setting of priorities affecting all research and development in environmental science sup- ported by the Federal Government. (2) The determination of appropriate and feasi- ble time schedules for the projects of the national program and ensuring that projects are managed in accordance with such schedules. (3) The provision of full coordination of the efforts of all Federal agencies engaged in the support or performance of research in environ- mental science, quite apart from efforts in appli- cation or regulation. (4) The establishment of organizational and employment incentives suitable for the types of projects that are characteristic of environmental science through the support of national centers and specialized institutes. 392 APPENDIX (5) The encouragement of State and local gov- ernments and private supporting organizations to subscribe to the national program, as it is devel- oped, and to the pattern of priorities adopted. With respect to the organizations where the work of envi- ronmental science is done, several considerations are of the greatest importance. Environmental science, as defined in this report, should be viewed as a distinctive type of activity lying between the extremes of traditional, basic science, on the one hand, and the organizations established by society for the application and use of science and technology. It shares the scientific motivations of the former and the multidisciplinary and organizational complexity of the latter. Various types of organizational structures should thus be attempted, as experiments in the manage- ment of environmental science. Two conclusions are especially important: (a) In academic institutions, which employ two- thirds of the manpower in environmental science, the need for strong departmental structures has historically hindered the development of effective interdepartmental programs. Within the last few years, however, new capability and experience in systems management, often combined with central funding for complex problems, have given a new vitality to multidisciplinary efforts. A few research institutes and national laboratories have also begun ambitious multidisciplinary studies of envi- ronmental problems. These experiments in orga- nization should be continued, expanded, and followed closely. (b) Industry possesses great capability in sys- tems analysis and systems management, but rarely offers the broad array of scientific competence needed in environmental science. Government has additional strengths, particularly in the application of environmental science to environmental man- agement. A more effective use of these resources can be made by combining the talents of industry, government, and universities in new types of research organizations and by seeking new ap- proaches to the management of environmental science. 4. FUNDING FOR ENVIRONMENTAL SCIENCE If progress in environmental science is to be made at an acceptable rate it is essential that additional manpower be made available both through education and through transfer from other fields and activities. This will occur only if appro- priate employment opportunities and incentives are provided. The character of funding is especially important to this end. In addition to the opportunity provided by new types of organizations, as recommended above, provision should be made for continuity of funding of programs of environmental science as being one of the principal means for attracting the best talent. It is further recommended that the funding of equipment, facilities, and logistics for environ- mental science be consistent with scientific needs and opportunities. The highest priority should be given to the needs of multidisciplinary teams en- gaged in the study of environmental systems. 5. DEVELOPMENT OF ADDITIONAL MANPOWER While it is essential that the disciplinary strength of aca- demic institutions be maintained and increased across all fields of science, these institutions also have a responsibility specifi- cally with respect to the manpower of environmental science. Although competent specialists transferring from related disciplines can constructively enter fields of environmental science through on-the-job training, the process can often be faster and more effective if retraining opportunities are available within the educational context. Hence, it is rec- ommended that colleges and universities consider appropriate means for supplementary education in environmental science for scientific and tech- nical personnel. Of special importance to implementing a na- tional program for environmental science is the existence of an informed citizenry, both as a source of future scientists and as the necessary basis for national understanding and motivation of the entire program. The colleges and univer- sities thus have a special opportunity to contribute by the development of new curricula in which to present the perspective of environmental science, as well as of new courses and programs, especially directed to the undergraduate. Manpower needs related to environmental science are not confined to the scientists, engineers, technicians, and others who contribute to scientific progress. As environmental science advances, there will be an increasing need for "natural resource administrators" to serve in local, State, or Federal governments. The education of these public administrators involves two types of interdisciplinary training. On the one hand, scientists and engineers must gain a better understanding of the social, economic, legal, and political environment within which prac- tical action must be sought. On the other hand, students of public administration must gain a better perception of the scientific process and a better understanding of how scientists can contribute effectively to the practical solution of environ- mental problems. It is recommended that substantial and adequate funding be made available for these purposes. Even with the implementation of these recommendations only gradual progress can be anticipated. Environmental sci- ence is too difficult, too broad in scope, and too near the begin- ning for an effective match with societal need to be achieved during this decade. But, correspondingly, the stakes are too high to miss the opportunity for making the 1970's the base on which a constructive future for mankind will be established. 393 SELECTED REFERENCES The following references are furnished to enable the reader to go beyond the material presented in this book. Most of the references are readily available, although there are some that, of necessity, are in more abstruse scientific journals. In some cases, classics in the field are cited because of their importance. These references are by no means all- inclusive or exhaustive. They serve only as a bridge to more complete and comprehensive information in the several areas discussed. I. THE SOLAR-TERRESTRIAL ENVIRONMENT Chamberlain, J. W., 1961: Physics of the Aurora and Airglow. Academic Press, Inc., New York, N.Y. Committee on Solar-Terrestrial Research, 1969: Physics of the Earth in Space: The Role of Ground-Based Research. National Research Coun- cil, National Academy of Sciences, Washington, D. C. Kavanaugh, L. D., Jr., L. W. Schardt and E. C. Roelof, 1970: "Solar Wind and Solar Energetic- Particles: Properties and Interactions," Reviews of Geophysics and Space Physics, 8, 389-460. King, J. W. and W. S. Newman (eds.), 1967: Solar- Terrestrial Physics. Academic Press, Inc., New York, N.Y. Space Science Board, 1971 : Priorities for Space Re- search 1971-1980. National Research Council, National Academy of Sciences, Washington, D. C. Whitten, R. C. and I. G. Poppoff, 1965: Physics of the Lower Ionosphere. Prentice Hall, Inc., Engle- wood Cliffs, N.J. Williams, D. J. and G. D. Mead (eds.), 1969: "Inter- national Symposium on the Physics of the Mag- netosphere," Reviews of Geophysics and Space Physics, 7, 1-459. Wolfe, J. H. and D. S. Intriligator, 1970: "The Solar Wind Interaction with the Geomagnetic Field," Space Science Reviews, 10, 511-596. II. DYNAMICS OF THE SOLID EARTH Aggarwal, Y. P., L. R. Sykes, J. Armbruster and M. L. Sbar, 1973: "Premonitory Changes in Seis- mic Velocities and Prediction of Earthquakes," Nature, 241, 101-104. Committee on Geological Sciences, 1972: The Earth and Human Affairs. National Research Council, National Academy of Sciences. Canfield Press, San Francisco, Calif. Division of Earth Sciences, 1969: Resources and Man. National Research Council, National Acad- emy of Sciences. W. H. Freeman & Co., San Francisco, Calif. Division of Earth Sciences, 1969: Toward Reduc- tion of Losses from Earthquakes. National Re- search Council, National Academy of Sciences, Washington, D. C. Drake, C. L., 1970: The Geological Revolution. Con- don Lectures, Oregon State System of Higher Education, Eugene, Ore. Frye, J. C, 1971: A Geologist Views the Environ- ment. Environmental Geology Notes (No. 42), Illinois State Water Survey, Urbana, 111. Gass, I. G., P. J. Smith and R. C. L. Wilson (eds.), 1971: Understanding the Earth. The Open Uni- versity, The Artemis Press, Sussex, England. Geodynamics Committee, 1971 : "Geodynamics Project: Development of a U.S. Program," £©S, Transactions, American Geophysical Union, 52, 396-405. Geophysics Research Board, 1964: Solid-Earth Geo- physics: Survey and Outlook. National Research Council, National Academy of Sciences, Wash- ington, D. C. Geophysics Research Board, 1969: The Earth's Crust and Upper Mantle. National Research Council, National Academy of Sciences, Wash- ington, D. C. Robertson, E. C. (ed.), 1972: The Nature of the Solid Earth. McGraw-Hill Book Co., Inc., New York, N.Y. Sanders, H. J. (assoc. ed.), 1967: "Chemistry and the Solid Earth," Chemistry and the Environment, the Solid Earth, the Oceans, the Atmosphere, 2A-19A, American Chemical Society, Washing- ton, D. C. Schmidt, R. G. and H. R. Shaw, 1972: Atlas of Vol- canic Phenomena. U.S. Geological Survey, De- partment of Interior, Washington, D. C. III. CLIMATIC CHANGE Brooks, C. E. P., 1949: Climate Through the Ages. Dover Publications, Inc., New York, N.Y. 395 SELECTED REFERENCES IV. Budyko, M. I., 1072: "The Future Climate," EffiS, Transactions, American Geophysical Union, 53, 868-874. Lamb, H. H., 1966: The Changing Climate. Methuen and Co., Ltd., London, England. Lamb, H. H., 1970: "Volcanic Dust in the Atmos- phere with Chronology and Assessment of Its Meteorological Significance," Philosophical Trans- actions of the Royal Society, 266, 425-533. Landsberg, H. E., 1«70: "Man-Made Climatic Changes," Science, 170, 1265-1274. Lorenz, E. N., 1970: "Climatic Change as a Mathe- matical Problem," Journal of Applied Meteorol- ogy, 9, 325-329. Mitchell, J. M., Jr., 1968: "Causes of Climatic Change," Meteorological Monographs, S, 1-159. Sellers, A. D., 1^69: "A Global Climate Model Based on the Energy Balance of the Earth-Atmos- phere System," Journal of Applied Meteorology, 8, 392-400. Shapely, H. (ed.), 1953: Climatic Change: Evidence, Causes and Effects. Harvard University Press, Cambridge, Mass. Study of Critical Environmental Problems (SCEP), 1970: Man's Impact on the Global Environment. The MIT Press, Cambridge, Mass. Study of Man's Impact on Climate (SMIC), 1971: Inadvertent Climate Modification. The MIT Press, Cambridge, Mass. DYNAMICS OF THE ATMOSPHERE-OCEAN SYSTEM Bater, D. J., 1969: "Models of Ocean Circulation," Scientific American, 221, 114-121. Bjerknes, ]., 1969: "Atmospheric Telecommunica- tions from the Equatorial Pacific," Monthly Weather Review, 97, 163-172. Changnon, S. A., Jr., 1969: "Recent Studies of Ur- ban Effects on Precipitation in the United States," Bulletin of the American Meteorological Society, 50,411-421. Committee on Atmospheric Sciences, 1966: The Feasibility of a Global Observation and Analysis Experiment. National Research Council, National Academy of Sciences, Washington, D. C. Dutton, J. A. and H. A. Panofsky, 1^70: "Clear Air Turbulence: A Mystery May be Unfolding," Science, 167, 937-944. Haltiner, G. J., 1971: Numerical Weather Predic- tion. John Wiley & Sons, Inc., New York, N.Y. Manabe, S. and K. Bryan, 1969: "Climate and the Ocean Circulation," Monthly Weather Review, 97, 739-827. Munk, W. H., 1966: "Abyssal Recipes," Deep Sea Research, 13, 707-730. Newell, R. E., 1971: "The Global Circulation of Atmospheric Pollutants," Scientific American, 224, 32-42. Petterssen, S., 1956: Weather Analysis and Fore- casting (2nd ed.) (2 volumes). McGraw-Hill Book Co., Inc., New York, N.Y. Shuman, F. S. and J. B. Hovermale, 1968: "An Op- erational Six-Layer Primitive Equation Model," Journal of Applied Meteorology, 7, 525-547. Stewart, R. W., 1969: "The Atmosphere and the Ocean," Scientific American, 221, 76-86. Stommel, H., 1965: Gulf Stream: A Physical and Dynamical Description. University of California Press, Berkeley, Calif. Stommel, H., 1970: "Future Prospects for Physical Oceanography," Science, 168, 1531-1537. Sverdrup, H. U., M. W. Johnson and R. H. Fleming, 1942: The Oceans. Prentice-Hall, Inc., Englewood Cliffs, N.J. V. SEVERE STORMS Chalmers, J. A., 1967: Atmospheric Electricity (2nd ed.). Pergamon Press, Inc., New York, N.Y. Dunn, G. E. and B. I. Miller, 1964: Atlantic Hur- ricanes (2nd ed.). Louisiana State University Press, Baton Rouge, La. Flora, S. D., 1954: Tornadoes of the United States. University of Oklahoma Press, Norman, Okla. Fujita, T. T., 1965: "Palm Sunday Tornadoes of April 11, 1965," Monthly Weather Review, 9S, 29-69. Gentry, R. C, 1969: "Project Stormfury," Bulletin of the American Meteorological Society, 50, 404- 409. Gentry, R. C, 1970: "Hurricane Debbie Modifica- tion Experiments, August 1969," Science, 168, 473-475. Kessler, E., 1970: "Tornadoes," Bulletin of tlie American Meteorological Society, 51, 926-936. Musil, D. J., 1970: "Computer Modeling of Hail- stone Growth in the Feeder Clouds," Journal of the Atmospheric Sciences, 27, 474-482. Orville, R. E., 1968: "A High-Speed Time-Resolved Spectroscopic Study of the Lightning Return Stroke," Journal of the Atmospheric Sciences, 25, 827-856. Palmen, E. H. and C. W. Newton, 1969: Atmos- pheric Circulation Systems: Their Structure and Physical Interpretation. Academic Press, Inc., New York, N.Y. Rosenthal, S. L., 1970: "A Circular Symmetric Primitive Equation Model of Tropical Cyclone Development Containing an Explicit Water Vapor Cycle," Monthly Weather Review, 98, 643-663. 396 SELECTED REFERENCES Sulakvelidze, G. K., 1969: Rainstorms and flail (translated from Russian). U.S. Department of Commerce (TT 68-50446), National Technical Information Service, Springfield, Va. Uman, M A., 1069: Lightning. McGraw-Hill Book Co., Inc., New York, N.Y. VI. PRECIPITATION AND REGIONAL WEATHER PHENOMENA Appleman, H. S. and F. G. Coons, Jr., 1970: "The Use of Jet Aircraft Engines to Dissipate Warm Fog," Journal of Applied Meteorology, 9, 464- 466. Battan, L. J., 1967: "Silver-Iodide Seeding and Pre- cipitation Initiation in Convective Clouds," Journal of Applied Meteorology, 6, 317-322. Beckwith, W. B., 1968: "An Analysis of Airport Fog Dispersal Operations with Giant Hygro- scopic Nuclei," Journal of Applied Meteorology, 7, 860-869. Biswas, K. R., R. K. Kapoor, K. K. Kanuga and B. V. Ramanta Murty, 1^67 : "Cloud Seeding Ex- periment Using Common Salt," Journal of Ap- plied Meteorology, 6, 914-923. Carlson, T. N. and J. M. Prospero, 1972: "The Large-Scale Movement of Saharan Air Out- breaks over the Northern Equatorial Atlantic," Journal of Applied Meteorology, 11, 283-297. Committee on Atmospheric Sciences, 1966: Weather and Climate Modification : Problems and Pros- pects. National Research Council, National Acad- emy of Sciences, Washington, D. C. Fleagle, R. G. (ed.), 1968: Weather Modification, Science and Public Policy. University of Wash- ington Press, Seattle, Wash. Flowers, E. C, R. A. McCormick and K. R. Kurfis, 1969: "Atmospheric Turbidity over the United States, 1961-1966," Journal of Applied Meteor- ology, 8, 955-962. Jiusto, J. E., R. S. Pilie and W. C. Kocmond, 1968: "Fog Modification with Giant Hygroscopic Nu- clei," Journal of Applied Meteorology, 7, 860- 869. Mielke, P. W., L. O. Grant and C. F. Chappell, 1970: "Elevation and Spatial Variation Effects of Wintertime Orographic Cloud Seeding/' Journal of Applied Meteorology, 9, 476-488. Namias, J., 1966: "Nature and Possible Causes of the Northeastern United States Drought During 1962-65," Monthly Weather Review, 94, 543- 554. Ramage, C. S., 1971: Monsoon Meteorology. Aca- demic Press, Inc., New York, N.Y. Riehl, H., 1954: Tropical Meteorology. McGraw- Hill Book Co., Inc., New York, N.Y. Simpson, J. and V. Wiggert, 1970: "Rainfall En- hancement by Dynamic Cloud Modification," Science, 170, 127-132. Sugg, A. L., 1968: "Beneficial Aspects of the Tropi- cal Cyclone," Journal of Applied Meteorology, 7, 39-45. Taubenfeld, H. J. (ed.), 1970: Controlling the Weather: A Study of Law and Regulatory Proc- esses. The Dunnellen Co., Inc., New York, N.Y. VII. WATER RESOURCES, FORESTRY AND AGRICULTURE Bormann, F. H., G. E. Likens, D. W. Fisher and R. S. Pierce, 1968: "Nutrient Loss Accelerated by Clear-Cutting of a Forest Ecosystem," Science, 159, 882-884. Bosselman, F. and D. Callies, 1972: The Quiet Revolution in Land Use Control. Council on En- vironmental Quality, U.S. Government Printing Office, Washington, D. C. Byerly, T. C, 1966: "The Role of Livestock in Food Production," Journal of Animal Science, 25, 552- 566. Calder, R., 1962: Common Sense about a Starving World. MacMillan Co., Inc., New York, N.Y. Coffman, W. P., K. W. Cummins and J. C. Wuy- check, 1971: "Energy Flow in a Woodland Stream Ecosystem: I Tissue Support Trophic Structure of the Autumnal Community," Archives of Hy- drobiology, 68, 232-276. Guy, H. P., 1970: Sediment Problems in Urban Areas. U.S. Geological Survey Circular 601-E, U.S. Department of Interior, Washington, D. C. Hayami, Y. and V. W. Ruttan, 1971: Agricultural Development: An International Perspective. The Johns Hopkins Press, Baltimore, Md. Kneese, A. V., 1965: Economic and Related Prob- lems on Water Resources Management. Resources for the Future Reprint 55, Washington, D. C. Loomis, R. S. and W. A. Williams, 1963: "Maxi- mum Crop Productivity: An Estimate," Crop Science, 3, 67-72. Oglesby, T. R., C. A. Carlson and J. A. McCann (eds.), 1972: River Ecology and Man. Academic Press, Inc., New York, N.Y. Panel on the World Food Supply, 1967: The World Food Problem, Vols. I and 11. President's Science Advisory Committee, U.S. Government Printing Office, Washington, D. C. Schmitt, W. R., 1965: "The Planetary Food-Poten- tial," New York Academy of Science Annals, 118, 645-718. National Water Commission, 1973: Water Policies for the Future. U.S. Government Printing Office, Washington, D. C. 397 SELECTED REFERENCES Watt, K. E. F., 1967: Ecology and Resource Man- agement: A Quantitative Approach. McGraw- Hill Book Co., Inc., New York, N.Y. VIII. AQUATIC ECOSYSTEMS Bardach, J. E. and J. H. Ryther, l^oS: The Status and Potential of Aquaculture, II, Particularly Pish Culture. U.S. Department of Commerce (BP 177-768), National Technical Information Service, Springfield, Va. Barnes, H., 1964-72: Oceanography and Marine Biology, An Annual Review. George Allen and Unwin Ltd., London, England. Coker, R. E., 1962: This Great and Wide Sea. Harper and Row, Inc., New York, N.Y. Costlow, J. D., Jr. (ed.), 1971: Fertility of the Sea, 1 & 2. Gordon and Breach Science Publishers, Inc., New York, N.Y. Gannon, J. E., 1969: Great Lakes Plankton Investi- gations: A Bibliography. Special Report 7, Uni- versity of Wisconsin Center for Great Lakes Studies, Madison, Wis. Hardy, A., 19o5: The Open Sea, I & 2. Houghton Mifflin Co., Inc., New York, N.Y. Hedgpeth, J, W. (ed.), 1957: Treatise on Marine Ecology, Vol. 1. Memoir of the Geological So- ciety of America, Vol. 67 (No. 1), Boulder, Colo. Hill, M. N. (ed.), 1963: The Sea (Vol. 2). John Wiley and Sons, Inc., New York, N.Y. Hutchinson, G. E., 1957: Treatise on Limnology, 1. John Wiley and Sons, Inc., New York, N.Y. Jorgensen, C. B., 1966: The Biology of Suspension- Feeding Organisms. Pergamon Press, Inc., New York, N.Y." Marshall, S. M. and A. P. Orr, 1^55: Biology of a Marine Copcpod. Oliver and Boyd, London, England. Milway, C. P., 1968: Eutrophication in Large Lakes and Impoundments. Organization for Economic Cooperation and Development, Paris, France. Moiseev, P. A., 1969: The Living Resources of the World Ocean (translated from Russian). U.S. Department of Commerce (TT 71-50026), Na- tional Technical Information Service, Springfield, Va. Planning Committee for the International Sym- posium on Eutrophication, 1969: Eutrophication: Courses, Consequences and Correctives. National Academy of Sciences, Washington, D. C. Raymont, J. F. G., 1963: Plankton and Productivity of the Oceans. Pergamon Press, Inc., New York, N.Y. Revelle, R., 1969: "The Ocean," Scientific Ameri- can, 221, 54-65. Ruttner, F., 1952: Fundamentals of Limnology. Uni- versity of Toronto Press, Toronto, Canada. Ryther, J. H., 1969: "Photosynthesis and Fish Pro- duction in the Sea," Science, 166, 72-76. Ryther, J. H. and J. E. Bardach, 1968: The Status and Potential of Aquae ultitre, I, Particularly In- vertebrate and Algae Culture. U.S. Department of Commerce (BP 177-767), National Technical Information Service, Springfield, Va. Steele, J. H. (ed.), 1970: Marine Food Chains. Uni- versity of California Press, Berkeley, Calif. IX. TERRESTRIAL ECOSYSTEMS Andrewartha, H. G. and L. C. Birch, 1954: The Dis- tribution and Abundance of Animals. University of Chicago Press, Chicago, 111. Cooper, C. F., 1961: "The Ecology of Fire," Scien- tific American, 204, 150-160. Darling, F., 1960: "Wildlife Husbandry in Africa," Scientific American, 203, 123-138. Darlington, P. J., 1957: Zoogeography. John Wiley and Sons, Inc., New York, N.Y. Dasmann, R. F., 1968: Environmental Conservation (2nd ed.). John Wiley and Sons, Inc., New York, N.Y. Ehrlich, P. R., 1968: The Population Bomb. Ballan- tyne Books, Inc., New York, N.Y. Ehrlich, P. R. and A. H. Ehrlich, 1970: Population, Resources, Environment: Issues in Human Ecol- ogy. W. H. Freeman and Co., San Francisco, Calif. Hairston, N. G., F. E. Smith and L. B. Slobodkin, 1960: "Community Structure, Population Con- trol and Competition," American Naturalist, 94, 421-425. Hardin, G., 1968: "The Tragedy of the Commons," Science, 162, 1243-1248. Hazen, W. E., 1964: Readings in Population and Community Ecology. W. B. Saunders Co., Phila- delphia, Pa. Huffaker, C. B. (ed.), 1971: Biological Control. Plenum Press, New York, N.Y. Hutchinson, G. E., 1970: "The Biosphere," Scien- tific American, 223, 44-53. Kendeigh, S. C, 1961: Animal Ecology. Prentice- Hall, Inc., Englewood Cliffs, N.J. Kormondy, E. J. (ed.), 1965: Readings in Ecology. Prentice-Hall, Inc., Englewood Cliffs, N.J. Lack, D., 1954: The Natural Regulation of Animal Numbers. The Oxford University Press, London, England. Odum, E. P. (ed.), 1971: Fundamentals of Ecology. W. B. Saunders Co., Philadelphia, Pa. 398 SELECTED REFERENCES Odum, E. P., 1Q63: Ecology. Holt, Rinehart and Winston, Inc., New York, N.Y. Odum, H. T., 1971: Environment, Power, Society. John Wiley and Sons, Inc., Interscience Pub- lishers, New York, N.Y. Van Dyne, G., 1969: The Ecosystem Concept in Natural Resource Management. Academic Press, Inc., New York, N.Y. Workshop on Global Ecological Problems, 1972: Man in the Living Environment. Institute of Ecology Report, University of Wisconsin Press, Madison, Wis. ENVIRONMENTAL CONTAMINANTS Agricultural Board, 1972: Pest Control Strategies for the Future. National Research Council, Na- tional Academy of Sciences, Washington, D. C. Blanchard, D. C. and L. D. Syzdek, 1972: "Concen- tration of Bacteria in Jet Drops from Bursting Bubbles," Journal of Geophysical Research, 77, 5087-5099. Brittin, W. E„ R. West and R. Williams (eds.), 1972: Air and Water Pollution. Colorado Asso- ciated University Press, Boulder, Colo. Butcher, S. S. and R. J. Charlson, 1972: An Intro- duction to Air Chemistry. Academic Press, Inc., New York, N.Y. Cairns, J. Jr., G. R. Tonza and B. C. Parker, 1972: "Pollution Related Structural and Functional Changes in Aquatic Communities with Emphasis on Freshwater Algae and Protozoa," Proceedings of the Academy of Natural Sciences of Philadel- phia, Pa., 124, 79-127. Committee on Plant and Animal Pests, 1969: Insect Pest Management and Control. National Research Council, National Academy of Sciences, Wash- ington, D. C. Division of Medical Sciences, 1962: Tropical Health: A Report on a Study of Needs and Resources. National Research Council, National Academy of Sciences, Washington, D. C. Eagen, B. A. and J. R. Mahoney, 1972: "Applica- tions of a Numerical Air Pollution Transport Model to Dispersion in the Atmospheric Bound- ary Layer," Journal of Applied Meteorology, 11, 1023-1039. Garlick, J. P. and R. W. J. Keay, 1970: Human Ecology in the Tropics. Pergamon Press, Inc., New York, N.Y. Goldberg, E. A. (convener), 1972: Baseline Studies of Pollutants in the Marine Environment and Research Recommendations. The IDOE Baseline Conference, May 24-26, 1972, New York, N.Y. Gregory, P. H., 1973: Microbiology of the Atmos- phere (2nd ed.). Halsted Press, New York, N.Y. Hidy, G. M. and J. R. Brock, 1^70: The Di of Aerocolloidal Systems. Pergamon Press, Inc., New York, N.Y. Leighton, P. A., 1961: Photochemistry of Air Pollu- tion. Academic Press, Inc., New York, N.Y. Ocean Science Committee, 1971: Marine Environ- mental Quality. National Research Council, Na- tional Academy of Sciences, Washington, D. C. Olson, T. A. and F. J. Burgess (eds.), 1967: Pollu- tion and Marine Ecology. John Wiley and Sons, Inc., Interscience Publishers, New York, N.Y. Pimental, D., 1971: Ecological Effects of Pesticides on Non-Target Species. Office of Science and Technology, U.S. Government Printing Office, Washington, D. C. Rabb, R. L. and F. E. Guthrie (eds.), 1970: Concepts of Pest Management. North Carolina State Uni- versity Press, Raleigh, N.C. Singer, S. F. (ed.), 1970: Global Effects of Environ- mental Pollution. Springer-Verlag, New York, N.Y. Stern, A. C. (ed.), 1968: Air Pollution (2nd ed.). Academic Press, Inc., New York, N.Y. Sykes, G. and F. A. Skinner (eds.), 1971: Microbial Aspects of Pollution, A Symposium. Academic Press, Inc., New York, N.Y. Wood, D. L., R. M. Silverstein and M. Nakajima, 1970: Control of Insect Behavior by Natural Products. Academic Press, Inc., New York, N.Y. XI. HUMAN ADAPTATION TO ENVIRONMENTAL STRESS Aiger, J. S., 1971: "Early Cultural Identification in Southwestern Alaska," Science, 171, 87-88. Baker, P. T., 1969: "Human Adaptation to High Altitudes," Science, 163, 1149-1156. Baker, P. T. and J. S. Weiner (eds.), 1966: The Biology of Human Adaptability. Oxford Uni- versity Press, London, England. Chagnon, N. A., 1968: Yanomama: The Fierce Peo- ple. Holt, Rinehart and Winston, Inc., New York, N.Y. Cohen, S. I., M. Deane and J. R. Goldsmith, 1969: "Carbon Monoxide and Survival from Myo- cardial Infarction," Archives of Environmental Health, 19, 510-517. Goldsmith, J. R., 1969: "Air Pollution Epidemiol- ogy," Archives of Environmental Health, 18, 516- 522. Goldsmith, J. R., 1970: "Contributions of Motor Vehicle Exhaust, Industry, and Cigarette Smok- ing to Community Carbon Monoxide Exposures," Annals of the New York Academy of Sciences, 174, 122-134. 399 SELECTED REFERENCES Hanna, J. M., 1971: "Responses of Quechua Indians to Coca Ingestion during Cold Exposure/' American Journal of Physical Anthropology, 34, 273-277. Little, M. A., R. B. Thomas, R. B. Mazess and P. T. Baker, 1971: "Population Differences and Developmental Changes in Extremity Tempera- ture Responses to Cold Among Andean Indians," Human Biology, 43, 70-91. Livingstone, F. B., H. Gershowitz, J. V. Neel, W. W. Zuelzer and M. D. Solomon, 1960: "The Distri- bution of Several Blood Group Genes in Liberia, the Ivory Coast and Upper Volta," American Journal of Physical Anthropology, 18, 161-178. Milan, F. A., 1968: "The International Study of Eskimos," Arctic, 21, 123-126. Neel, J. V., 1970: "Lessons from a Primitive Peo- ple," Science, 170, 815-822. Neel, J. V., VV. R. Centerwall, N. A. Chagnon and H. L. Casev, 1970: "Notes on the Effect of Measles and Measle Vaccine in a Virgin-Soil Population of South American Indians," Ameri- can Journal of Epidemiology, 91, 418-429. Ward, R. H. and J. V. Neel, 1970: "Gene Frequen- cies and Microdifferentiation among the Makiri- tore Indians, IV — Comparison of a Genetic Net- work with Ethnohistory and Migration Matrices: A New Index of Genetic Isolation," American Journal of Human Genetics, 22, 538-561. Wohlwill, J. F. and D. H. Carson (eds.), 1972: En- vironment and the Social Sciences: Perspectives and Applications. American Psychological Asso- ciation, Inc., Washington, D. C. World Health Organization, 1972: Health Hazards of the Human Environment. World Health Orga- nization, Geneva, Switzerland. Youseff, M. K., S. M. Horvath and R. W. Bullard, 1972: Physiological Adaptations: Desert and Mountain. Academic Press, Inc., New York, N.Y. 400 INDEX Absorption radiation aerosols, 58, 89 water in forest canopy, 202 Abyssinian Plateau, Africa, 123 Accademia del Cimento, Florence, Italy, 51 Acclimatization: high altitudes, 380, 381, 382 Accumulation: cloud zone, 149, Fig. V-13 Acoustic waves: volcanic eruptions, 44 Actinic rays in urban areas, 117 Adaptation climatic high altitude, 379-385 skin color, 375 genetic see Natural selection human limitations, 387 to air pollution, 338, 385-390 to high altitude, 379-385 to tropical climates, 378 technological, 338 Adelie penguins, 232 A-disciplinary problems see Multidisciplinary problems Advection in water cycle, 202 AEC, see Atomic Energy Commission, U.S. Aerobiology, 339-349 particulates, Fig. X-6 Aerobiology Program, U.S. (IBP), 339, 342, 344 Aerosols in atmosphere, 55, 58, 69 effect on circulation, 89, 91 effect on climate, 64, 116 effect on precipitation, 192 effect on radiation balance, 67, 68 in troposphere, detection by radar, 112 see nlso Nucleating agents; Nuclei; Particulates Aesthetics Corpus Christi Bay, Fig. VIII-10 forest management, 293 lakes, 260 of the environment, 338 oil on ocean surface, 361 Africa agriculture, 74, 215, 220, 242, 291, 297 arable land, Fig. VII-8 atmosphere-ocean system, 82, 191, 192, 193, 194, 358 climatic change, 51, 52, 69, 72 data networks, 59 earth processes, 27, 28, 32, 33, 44 environmental contamination, 217, 329, Fig. X-12, 364-367 human adaptation, 376, 377 severe storms, 123, Fig. V-l, 154, Fig. VI-10 tropical research facilities, 185 Aging processes human air pollution, 388 at high altitudes, 382, 383 lakes, 268 Agricultural planning crop management, 288 soil studies, 291 tropical areas, 295-298, 301 urban-induced weather changes, 115 Agriculture, 215-221 cattle, 74 crop rotation, 296 effects of parasitic disease on labor, Fig. X-20 effects of smog, 337 lessons from fossil plant studies, 74 pesticides and yields, Fig. X-12 polluting drainage, 248, 261, 273 water use, Fig. VII-1, 204 see also Agricultural planning; Farming; Land use; Soils Agriculture, U.S. Department of aerobiology research, 344 agricultural science, 218 lighting research, 160 see also Forest Service, U.S. Air: composition, 329 Air Force, U.S., 13, 15, 102, 181 see also Air Weather Service, U.S. Air Force Air pollution, see Pollution, Atmospheric Air quality control regions, 334 measurement, 333, Fig. X-4 models, 335-336 standards, 334 Air-sea rhythms, see Ocean-atmosphere system Air Weather Service, U.S. Air Force, 13, 102, 103 Aircraft cloud seeding, 154, 173, 176 fog seeding, 180, 181, 182, 183 jets, 65, 69, 103 lightning and, 157-158 radar, 111 turbulence and, 105, 106, 107, Fig. IV-10 weather monitoring, 98, 124, 129, 193, 194 see also Aviation Airports air pollution measurement, 334 fog dispersal, 181, 182, 183 weather prediction needs, 101, 102, 103, 104 Aitken, J., 193 Aitken nuclei, 193 Alabama, 147 Alaska, 32, 69, 87, 181 earthquakes, 35, 40 marine areas, 242, 244, 246 polar ecosystems, Fig. IX-15, 314, Fig. IX-16 volcanoes, 41, 42, 44, 46 weather modification, 101 Alazani Valley, Caucasus Mts., 151 Albedo of the earth, 66-69, Fig. III-7, 70, 71 atmospheric constituents, 89 climate and, 51, 52, 55 effect of dust, 194 tropical forests, 298 urban areas, 116 Alberta, Canada, 41, 154 Alder (tree), 208 Aleutian Islands, 35, 36, 44, 46 Alewives trophic dynamics of Great Lakes, 227, 228, Fig. VIII-2, Fig. VIII-14, 262, 263, 264, 266 Algae air pollution, Fig. X-6, 343, 345 Great Lakes, 264, 270 in chert deposits, 52 in forest ecosystem, 292 in harbors and lagoons, 233 in oceans, 236 Lake Washington, 272, Fig. VIII-17 macroscopic, in aquaculture, Fig. VIII-11 trophic dynamics, 225, 226, 227, 228 tundra 313, 314 Allergens, Airborne, 340, 342, 345-349 Alpha Helix, R.V. (ship), 233 Alpine glaciers, 52 Alps: plate deformation, 28 Altitude: human adaptation, 379-385 Aluminum oxides in tropical forests, 295 Amarillo, Texas, 204 Amazon River, 34, 187, 300 Amchitka Island, Aleutians, Alaska, 46 America, see United States Amery Ice Shelf, Antarctica, 84 Amitrole herbicide, 207 Ammonia: volcanoes, 43 Anaerobic basins, 55 Anakawa, Akio, 88 Anchovy fisheries food potential, 237, 238 Peru, 234 Andean Mts., S.A., 32 Anderson, J. P., 306 Anemometers, 347 Angell, James K., 109 Angstrom, A. J., 71 Animals energy budget, 289 horse, Fig. IX-7 ethology, 376 experimental air pollution studies, 387-388, 389 high altitude medicine, 384 fish protein as food for, 227-247 in forest ecosystems, 292, 302-305 fire and, 310, 312 tropics, 298 water quality and, 212 in tundra ecosystems, Fig. IX-16 plant eaters, 225 response in ecosystem, 289 source of food for man, 74, 217, 218 in oceans, 236 see also Carnivores; Game animals; Herbivores; Livestock; Mammals Anions: forest ecosystems, 294 Antarctic Treaty, 313, 314 401 INDEX Antarctica contamination, 330, 360 ecosystems, 313, 314 food chain, Fig. VIII-6, 351 food production, 217, 241 glaciation, 53, 54, 55 oceanic circulation and, 78, 83-84, Fig. IV-3, 98, 231-233, 239 see also Krill Anticyclones drought, 165, 167 prediction of, 93, 94 Apollo missions, 14, 158 Appalachian Mts., 31, 118 APT, see Automatic Picture Transmission Aquaculture prospects, 250-253 Aquatic ecosystems: modeling, 282 Aquatic plants, 236, 302 Aquifers, 203 Aquitards, 203 Arabian Sea, 358 Areata, Cal., 181 Arctic regions, 78, 79 air-sea rhythms, 86, 87 ecosystems, 313-315 food production, 217 pack-ice behavior, 58 see also Antarctica Ardrey, William B., 376 Argentina, 154, 241, 242, 369 Argonne National Laboratory (AEC), 257 Arid regions Africa source of dust in western hemisphere, 191 source of hurricanes, 123 maintenance of the biosphere, 280-285 gramagrass output, Fig. IX-4 mosquito submodel, Fig. IX-3 subtropical anticyclones, 165 water supply, 198 Arizona groundwater, 204 range management, 74 seismic refraction profile, 29, 31 University of, 306 Arkansas, 308 Armed Forces Epidemiological Board, U.S., 365 Armenia, 152 Armstrong, Bruce W., 388 Army, U.S., 136 Army Air Force, U.S., 46 Army Medical Research and Development Command, U.S., 365, 379 Aromatics, 361 Arsenic poisoning, 322, 357 Asama volcano, Japan, 45 Asbestos, 320 Ash, Volcanic as contaminant, 55, 56, 68, 71, 72, 329 falls and flows, 40, 41, 42, 44, 45 Asia agriculture, 220, 238, 251, 252, 297 climatic change, 57 data networks, Fig. IV— 7 environmental contamination, 364, 365 precipitation, Fig. VI-10, 185 Asphalts, 361 Assimilation capacity of lake water, 270 Asthma, 319, 385 Astrup, Paul, 386, 388 Atlanta, Ga., 189 Atlantic coast, 38, 135 Atlantic Ocean air-sea system, 78, 83, 84 climatic change, 57, 58 conservation, 246 data measurement, 79, 86, 91, 360 drought, 165, 167, 188 earth processes, 27, 28, 33, 53, 55 environmental contamination, 191, 192, 194, 329, 358 precipitation, 189 severe storms, 123, Fig. V-l, 126, 132, 147 weather forecasting, 185 Atlas, D., 109 Atmosphere, 3, 34, 52 158, 257 behavior, 62, 63 composition, 55, 286, 287 upper, 3, 10, 11-13, 167, 175 see n/so Pollution, Atmospheric Atmospheric circulation, 89-92 global, 64, 72 indicated by tree rings, Fig. Ill— 5 topics, 125, 188 dusts, 192 monsoons, 184 urbanization effects, 116 Atomic Energy Commission, U.S., 46, Fig. VI-11,259 see also Argonne National Laboratory; Brookhaven National Laboratory Auroral electrojet, 10 Auroral substorms, 5, 8 Australia agriculture, Fig. VII-8, 219 air-sea system, 358 climatic change, 57 earth processes, 44 ecosystems, 291, 297 human adaptation, 376 precipitation, 184, 185 water resources, 242 weather modification, 188 Automatic Picture Transmission (APT), 185 Avalanches, 42, 212 Aviation accidents, 108, 111, 117 noise pollution, 326 weather forecasting for, 101, 102, 103 weather reporting from, 105, 106 see also Aircraft Axelrod, Herman D., 330 Avres, S. M, 388 Azerbaidjan, U.S.S.R., 152 Azores Islands, 35, 135 B Backfires in forests, 310 Backus, Richard H., 361, 363 Bacteria air pollution, Fig. X-6, 342 in forest ecosystem, 292 oxidation of floating oil lumps, 362 soil, oxidation of CO, 358 Baja California, 240 Balchum, Oscar Joseph, 388 Baldwin Hills Dam, Los Angeles, Cal., 204 Baltic Sea, 52 Barbados, Antilles, 191, 193, 194, 329, 330, 358 see also BOMEX Barnacles, 241 on petroleum lumps, 361, 362, 363 Basalt, 29 Basin and Range Province, Nevada, 29, 31, 204 Batchelder, Arthur R., 306 Bears, 302 Beaufait, William R., 306 Beaver, 304 Bees and other pollinators, 351, 354, 355 Behavioral differences among populations, 373, 374, 376 Benchmark stations, 59, 331 Benefit/cost analysis effects of technology on the environ- ment, 338 environmental management, 283 fog dispersal at airports, 180-181, Fig. VI-9, 183 forest management, 206 pest controls, 351, 353, 356 water quality in Great Lakes, 270 weather changes, 172 Bengal, Bay of, 184 Bennett, Dudley W„ 389 Benthic marine communities, 231, 232 Benzene hexachloride, see Dieldrin Bering Sea, 74, 242, 244, 246 Bermuda, 191 Bermuda High, 165 Berry, Lester J., 219 Beryllium, 321 Bezymianny (volcano), 40 Biological effects air contaminants, 332 pesticides, 351 thermal discharges in lakes, 259 Biological extinction of animals climatic changes and, 73-74 magnetic field reversals and, 25 Stone Age hunters, 74 Biological materials as air pollutants, 339 Biomes, Major world, 285, Fig. IX-5 deciduous forest, 298 tundra, Fig. IX-15, 314, 315 see also Grassland ecosystem Biosphere, 3, 301 Birds malaria systems, 365 pesticides and, 351, 353, 357, 359 Bishop tuff, Cal., 42 Bivalves, 232, 237 Bjerknes, J., 167, 189 Black spruce, 311 Blackberries, 352 Blast waves from solar flares, 6 Blind areas for weather observations, 98 Blood groups, 373, 374 Bobcat, 302 402 INDEX BOMEX (Barbados Oceanographic and Meteorological Experiment), 125, 185, Fig. VI-11 Bormann, F. H., 294 Boundary layer of plant evaporation, 200, 201 Braham, Roscoe R., 171 Brazil air-sea system, 190 climatic change, 52 drought, 188 environmental disease, 367 human adaptation, 374, Fig. XI-1 mineral deposits, 33 range management, 74 Breton Island, Miss., 136 Bristlecone pine: tree ring studies, 61 Bronchitis, 319, 385, Fig. XI-8, 390 Brook, J., 139 Brookhaven National Laboratory (AEC), 348 Brooklyn Navy Yard, New York, 362 Browning, Keith A., 149 Brownsville, Texas, 135 Bryan, Kirk, Jr., 87 Bryozoa, 232 Budyko, M. I., 67, 68 Buell, P., 388 Building codes earthquake hazards, 39 hurricane protection, 136 Buildings and structures effects of air pollution, 319 effects of smog on, 337 polluting capacity of houses, 327, 385 see also Construction industry Buoys, 90, 190 ocean studies, 78, 79, 80, 82, 84, 87, 100 Bureau of Reclamation, U.S., 171, 172 Burkett, Howard B., 365 Burma, 184, 185 Cactus, Prickly-pear, 297 Cadmium poisoning, 322 Calcite, 193 Calcium chloride, 174 increase in Great Lakes, 268 California crust of earth, 29, 30, Fig. VII-3, 204 earthquakes, 26, 28, 30, 31, 33, 35 36, 37, Fig. II— 7, 39, 40 environment 336, 337, 351, 352, Fig. X-13, 385, 386, 390 fog dispersal, 181, 182 forests, 61, 207, Fig. VII-5 ocean areas, 87, 231, 240, 242, 245, 361, 362 trees, 61 volcanoes, 40, 41, 44 water, 33, 166, 199, 204, 211 California, University of, 66 California current: data measurements, 78 California Institute of Technology contamination research, 330 Cambrian era, 52 Cambridge Research Laboratories (U.S. Air Force), 13 Cameroons, W. Africa, 192 Canada air-sea system, 106 climatic change, 73 earth processes, 39 ecosystems, 314 environmental contamination, 267 severe storms, 133, 147, 151 Canton Island, Pacific, observatory, 84, Fig. 1V-4, 86, 87, 88 Cape Cod, Mass., 135 Cape Thompson, Alaska, 314 Cape Verde Islands, 135 Carbamates, 355 Carbon, 22, 32 carbon 14 insecticides, 234 measure of productive capacity of the sea, 236 circulation in forest ecosystems, 301 lake nutrients, 272 pollution particles, 358, 362 Carbon dioxide (CO^) advection in photosynthesis, 202 cloud seeding, 173, 174, 175 fog seeding, 180, 182, 183 hailstorm seeding, 153 heat balance of the earth, 287 in atmosphere, 34, 55, 56, 57, 58, 64, 89 120, 329, 333, 337, 357-358 amounts present, 67, 68, Fig. III-9, Fig. 111-10, 72 high altitudes, 382 moist tropics, 330 ocean absorption, 82, 233 urban areas, 119 land cultivation and changes in, 300 plant growth, 288, 289 quantity affected by man's activities, 286 Carbon monoxide (CO) air pollution and, 320, 330, 333, 337, 338, 358 human adaptation, 385-390 Carboniferous era, 329 Carboxyhemoglobin, 338, 388, Fig. XI-9 Caribbean Sea atmospheric dust, 191, 192 earth processes, 53, 54 severe storms, 123, Fig. V-l, 135 weather forecasting, 185 weather modification, 188 Carnivores food chain, 225, Fig. VIII-11, 286, Fig. IX-6, 304 Carp in Great Lakes, 261, 263, 266 Cascade Range, Wash.-Cal., 40 CAT, see Clear air turbulence Catfish, 251 Cations forest ecosystems, 294 Caucasus Mountains, U.S.S.R., 151, 152, 358, Fig. X-15 Cenozoic era, 52, 55 Center for Short-Lived Phenomena, Cambridge, Mass., 47 Central America, 35, 123, 246 Central Plains: weather, 146, 165 Ceraunograms: tropical weather fore- casting, 187 Cerra Negro (volcano), Costa Rica, 44 Chad Lake, Africa, 52 Chagas' disease, 217, 369-370 Chain reactions ecological balance of Great Lakes, 261 forest ecosystem response to population changes, 300 hurricane development, 125 ocean-atmosphere system, 88 Changnon, S. A., Jr., 152 Chaparral, 298 Charleston, S. C, 38 Charlson, Robert J., 330 Chemicals atmospheric pollutants, 118, 119, 332 marine contaminants, 357-360 see also Fertilizers; Insecticides; Pesticides; Pollution, Atmospheric Chemiluminescence quenching, 331 Chert deposits, 52 Chicago, 111., 113, 119, 257 Children, Growth of air pollution and, 388 high altitudes, Fig. XI-6, 385 tropical regions, 378 Chile, 240, 241, 242, 369 China, 184, 185, 186, 216, 357 China Seas, 184 Chitin, 240 Chlorinated hydrocarbons use on forest lands, 206 water-vapor pollution, 337 see also Insecticides; Pesticides Chlorine in Great Lakes, 268 Chloroplasts, 288 Cholesterol stores, 385 Christmas Island, 87 Chromium poisoning, 322 Chromosphere, 5 Chubs, see Ciscoes Chukchi Sea, 246 CIC (Committee on Institutional Cooperation), 269 Cigarette smoking: health hazards, 385, Fig. XI-8, 387, 388, 390 Cincinnati, Ohio, 114 Circular storms, 123 Circulatory diseases, 388 Ciscoes: Great Lakes, 261, 262, 263, 264 Citrus groves, 355 Clathration process: fog dispersal, 183 Claveran, Ramon, 306 Clay minerals ice nuclei, 192 in ocean sediments, 358 Clear air turbulence, 105-112 Clear cutting forests, 207, 210, 213 tropical areas, 296 Climate, 13, 34, 59, 62, 72 aerobiology, 344 affected by air-ocean system, 82, 85 gravitational field, 51 403 INDEX hurricanes, 133 volcanic ash, 41 water supply, 198, 212 change, 51-74, 180 regional, 57, 60 models, 64, 120 control, 55, 57, 58, 89 urbanization and, 113-120 vegetation fire and, 306 world's major biomes, Fig. IX-5 see also Precipitation; Weather Cloud seeding hail suppression, 151-155 hurricane modification, 126 lightning control, 158, 160-161, optimum conditions, Fig. VI-5 possible results, 57 precipitation changes, U.S., 170-179 Project STORMFURY, 128-132 seeding materials, Fig. VI-6, 178 simulation, Fig. VI-6 see also Seeding techniques for fog Clouds, 68, 108, 113, 174, 175 albedo of the earth and, 66, Fig. III-7, c8, 69, 71 atmospheric circulations, 89, 165 billow, 109 cirrus contrails and, 69 satellite measurement of, 103 cumulonimbus Caribbean area, 188 hailstorms and, 154 monsoon areas, 187, 188 tornadoes and, 138, 144 cumulus atmosphere-ocean system, 67, 91 cloud seeding, Fig. VI-6 dust and, 191, 192 hailstorms and, 150 hurricanes and, 125, 128, 130 nuclei, 170 cumulus congestus tropical areas, 188 lightning from, Fig. V-15 modification, 188 monsoon areas, 187 nucleation centers, 329 predictions, 102, 103 stratus clouds precipitation, 173 studies clusters, 126 via satellites, 87, 123 weather forecasting, Fig. IV-6, 95 water vapor and, 337 Coast Ranges, Cal., 29, 30 Coastal areas damage by hurricanes, 128, 133, 135 entrapment of water, 255 lakes upwelling, Fig. VIII-12 marine productivity, 233, 235, Fig. VIII-7 pollution, 254 tundra ecosystem, Fig. IX— 16 see also Shore zones Coastal Studies Institute, Louisiana State Univ., 134 Cobalt: lake nutrient, 272 Coffee cultivation, Fig. VII-9 Cohen, S. I., 390 Cold fog, 180, 182 Colorado cloud seeding, 171, 172, Fig. VI-5 hail storm research, 154 seismic monitoring, 31, 39 Colorado Plateau, 2" Columbia, Md., 118 Columbia Plateau, Wash., 29 Columbia River, Wash. -Ore., 40 Commerce, U.S. Department of, Fig. VI-11 Commission for Climatology, World Meteorology Organization (WMO), 59 Community air pollution, 319-321 Competition among plant species, 289 Computers ecosystem modeling analogue, 281 digital, 281, 285 hybrid, 281, 285 forest ecosystems, 300 simulation atmosphere-stagnation periods, 118 ocean productivity, 233, 235 use, 16, 352 space efforts, 16 weather forecasting, 91, 94, 97, 99, 101, 103, 104, 125, 141, Fig. V-10, 185 Condensation: fog dispersal, 181 Congenital defects, 383, 384 Conglomerate rocks, 203 Coniferous forests, see Forests Connecticut, 73, 336 Conservation air quality models, 335 aquaculture and, 251 gene pool, 278 water, 259 Constance, Lake (Ger.-Aus.-Switz.), 52 Construction industry impact of climatic change, 58, 59 structures resistant to earthquakes, 39 hurricanes, 136 tornados, 145 weather forecasting for, 101 Contaminants environmental, 329-370 Great Lakes, 264 marine, 330, 357-363 see Pollution, Atmospheric; Pollution, Water Continental drift, 26, 32, Fig. II-4 Continental margins: sea floor discontinuity, 29, 31 Continental shelf: storm damage near, 28, 135 Continentality, 52, 64, 190 Continuity equation for air quality models, 335 Continuous culture theory: oceans, 233 Convection earth's crust, 22 energy exchange for plants, 287 models, 47, 66, 67, 91, 140 precipitation stimulation, 173, 179 turbulence and, 108, 111 urban areas, llo, lio water resources and, 200 weather, 96, 128, 186, 187 Cooling towers, 259 Coon, Carleton S., 373, 377 Copepods, Fig. VIII-5 m food chain, 237 Copper, 32, 272 Coral reef, 232 Coral Sea, 186 Cordillera Mountains, S.A., 31, 32 Coriolis force, 254, 258, 269 Corn hybrid, 218 maize, 217 systems analysis of growing, 289 Corona of the sun, 3, 5 Corpus Christi Bay, Texas, 249 Costa Rica gas deposits, 43 mud flows, 42 volcanic eruptions, 40 volcanic science, 44 Costs, see Benefit/cost analysis; Economic effects Cotton production dependence on water supply, 204 pesticides and, 351, 355 Coulter, M. W., 228 Coulter method, 228 Council on Economic Growth, Technology and Public Policy, Committee on Institutional Cooperation (CIC), 269 Countryman, Clyde, 306 Cowan, J. Ritchie, 202 Cox, Charles S., 82 Coyote, 302, 304 Crater Lake, Ore., 40, 41 Crete, Greece, 44 Crossbills, 302 Crow, James F., 373 Crustaceans trophic dynamics, 226, 228, Fig. VIII-2, 237, 252 petroleum lumps and, 363 Cryogenics: fog modification, 183 Cultural enrichment of bodies of water, see Eutrophication Currents coastal, 128 lakes, 254, 255, 256, 270 lightning strokes, 161 ocean, 79, Fig. IV-2 tornadoes, 139 Cyanide: water contamination, 272 Cycles air-sea, 84-88 antarctic ocean currents, 84 biospheric, 285 climatic change, 57, 59-61 definition, 60 diurnal and seasonal, 51 glacial/interglacial, 51 motions of the earth, 54 ocean surface temperatures, Fig. Ill— 2 stratospheric winds, 51 sunspots, 52 404 INDEX Cyclones cellars, 135 drought, lt>5 prediction, 91, 93, 94, 98, 144 synoptic systems and, 128 tropical, 184, Fig. VI-12 see also Tornadoes Cystic fibrosis in European populations, 374 Cytogenetic studies of Yanomama Indians, Fig. XI-1, Fig. XI-2 D region of ionosphere, 9, 10-11 Dakar, W. Africa, 194 Dallas, Texas, 140 Damage/destruction by contaminants, 329 by forest fires, 207 by hailstorms, 151, Fig. V-12, 154 by hurricanes, 123, Fig. V-4, 128, 130, 133, 136, Fig. V-6 by lightning, 157, 160, 161 by solar energy, 8 by tornadoes, Fig. V-6, 144 by volcanoes, 42, 43, 44 by weather changes, 115 see also Disasters Daphnia, 227, 228, Fig. VIII-2 Darwin, Charles natural selection, 373, 374, 376, 377 sea floor contamination, 358 Data bases adaptation to air pollution, 387 adaptation to drought, 219-220 air-quality criteria, 334, 340 climatic statistics, 120 cloud seeding technology, 171, 175 drought prediction, 167 ecosystem modeling, 282 estimates of water supply, 197 forest ecosystems, 300 animal ecology, 302 fire, 307 hurricane surveillance, 131 marine environments, 231 North Pacific Ocean, 242 Puget Sound, 249 measuring aeroallergens, 345 sea-air system, 78, 80, 82, 87-88 trophic dynamics of Great Lakes, 227 urban-affected weather changes, 114 water quality of Great Lakes, 264, 268 weather forecasting, 90-92, 93, Fig. IV-7, Fig. IV-8, 98, 103 pilot reports, 106 tornadoes, 146 tropical areas, 188 Daubenmire, Rexford, 306 Davis, Margaret B., 73 Davis Sea, 232 DDD in lakes, 228 DDE in lakes, 228 DDT in antarctic animals, 241 in birds, 351, 359 in fish, 228, 359 in lake waters, 272 in oceans, 233, 245 in pesticides, 352, Fig. X-13, Fig. X-14, Fig. X-18 phytoplankton and, Fig. VIII— 3 temperatures and effects of, 57 use in forest areas, 207, 213 Deane, Margaret, 390 Death rates, 377, 378 air pollution and, 385 Deaths Chagas' disease, 369 high altitude, 379 hurricane caused, 127, Fig. V-5, 136 lightning caused, 157, 158 tornado caused, 137, 138 Decay term for air pollutants, 336 Deciduous forests, see Forests Decomposition in forest ecosystems, 292 Deer, White-tail, 302, 303, 305, 306, 310 Defense, U.S. Department of air-sea system, 108 BOMEX support, Fig. VI-11 data networks, 23 volcano technology, 47 see also Air Force, U.S.; Armed Forces Epidemiological Board, U.S.; Army, U.S.; Army Medical Research and Development Command, U.S.; Cambridge Research Laboratories; Naval Electronics Laboratory Center; Navy, U.S. Defoliation: effects on forests, 298 Deforestation ecological effects. Fig. IX-9 effect on climatic changes, 55 Dendroclimatological studies, 59 Denmark, 386 Density of water in lakes, 254 Dental caries, 379 dePena, R. G„ 151, 152 Desalination of sea water for equatorial areas, 187 Desert areas arid America, 73-74 ecosystem model, Fig. IX-3 monsoons and, 184, 186 soil studies, 291 solar radiation in, 55, Fig. Ill 10 see also Arid regions Dessens, J., 152-153 Detroit River, 263, 266 Developing nations agriculture, 218 effects of parasitic disease, Fig. X-20, 369 polluting technology, 330 deVries, A. L„ 232 Diabetes, 379 Diablo Range, Cal., 29, 30 Diamonds, 22 deposits, 32 Diatoms, Fig. VIII-4 Dieldrin, 369 Diet, sec Nutrition Diffusion air quality, 334,335 lake waters, 256, 257, 259 tornado modeling, 140 water within forest canopy, 202 Dinoflagellates, Fig. VIII-4 Disasters cactus growth in Australia, 297 marine monitoring, 231 Discover, USS (ship), 194 Diseases airborne, 340, 341, 343 causation contamination, 319-324, 327, 342, 343, 369 noise, 326 radiation, 325 environmental, 364-370 altitude-related, 379, 380, 383, 384, 385 genetic, 216, 373, 374 in animals, 217, 298, 303 in plants, 297, 300, 310 resistance to, 376, 378-379 smog and CO related, 385-390 see also Allergens, Airborne; Health; and names of specific diseases Diversion of water, 198, Fig. VII-1 Diving, 232, 233, 245 Djakarta, Indonesia, 86, Fig. IV-5 DOD, see Defense, U.S. Department of Dolphins toxicity in food chain, 363 tuna fishing and, 246 Douglas, J. W. B., 388 Douglas fir, 311 Drilling continental, 21-25, Fig. II— 1, 30, 31, 57, 59 ocean, 53, Fig. Ill— 3, 55 Dropsondes: air quality measurement, 334 Drought, 165-168 adjustments to, Fig. VII-10 agriculture and, 218-221, 278 air-sea interactions, 86 definition, 166 tropical areas, 184, 188 Drug action: effects at high altitudes, 379, 384, 385 Dunbar, M. J., 231 Dust Africa, 191-194, Fig. VI-13 effect on climate, 55, 56, 57-58, 59, Fig. 111-10 nucleation centers, 329 pollution factor, 327, Fig. X-6, 343, 358 solar radiation and, 55, 67, 68, 71 Soviet economy and, Fig. X-15 tropical forests and, 298 see also Aerosols Dust Bowl, Great Plains, 165 Dwarfism in crop yields, 216 Dynamo effect of earth's core, 24-25 Dynamo region of ionosphere, 10 Dzerdzeevskii, B. L., 72 E region of ionosphere, 9, 10 Earth continental U.S., 28, 31 crust, 21, 27 shock wave, from solar wind, 5 sun's influence on, 3-17 see also Earthquakes; Volcanoes 405 INDEX Earthquakes, 21, 22, 35-39, 135 effect on water quality, 212 locations, 26, Fig. II— 3, 28, 30 tidal waves, 81 volcanic eruptions and, 43 see also Seismicity of the earth Earthworms, 292 East, Edmund, 218 East River, New York, 362 EASTROPAC Program, 87, 88 Echinoderms, 232 Eclogite, 29 Ecology, 21 climatic change and, 34, 72 definition, 285 precipitation management and, 173, 175 surveys, 231 see also Ecosystems Economic effects aquaculture, 250-253 climatic changes, 57, 59 Corpus Christi Bay, Fig. VIII-10 costs of contaminants in air, 332, 333, 338 fisheries of Puget Sound, 249 fog modification, Fig. VI-9, 183 hail-suppression, 151, 154 hurricane modification, 128 lightning-caused damage, 160 long-range weather forecasting, 97-98, 100 parasitic diseases, 367, 369 pesticides, 353 precipitation management, 172, 173, 175, 177 subsidence in oil and water bearing formations, 203, 204 threat to tundra of developments, 313 tropical storms, 187-188, 189 turbulence, 108 urban-induced weather changes, 115 see also Benefit/cost analysis Ecosystems definition, 285 freshwater, 225-229 marine, 230-235 models, 209 studies of IBP, 58 terrestrial, 226 Eddy processes: ocean circulation, 80 Ekman, V. W., 79 Electrojets of ionosphere, 10 Electromagnet radiation lightning, 157 tornadoes and, 138-139 urbanization and, 113 Electrons: concentration in ionosphere, 9 Elephant-seals, 240, 241 Emery, K., 361, 362 Emiliani, Cesare, 54 Emphysema: air pollution and, 319, 385, Fig. XI-8, 387, 389, 390 Emulsifiers for floating oil, 362 Endrin: phytoplankton and, Fig. VIII— 3 Energy hailstorms, 149 hurricanes, 124, 125 lightning, 157 monsoons, 186 needed for food production, 216 sun, 51, 52, 55 tornadoes, 145 volcanic explosions, 44 waste generation, 330 Energy budget affected by urbanization, 116 clear air turbulence, 105, 106 cloud systems, 171 drought, 167 Great Lakes, 269 horse, Fig. IX-7 tropical areas, 187, 191, 194 water evaporation, 200 Energy transfer ecosystems, 225, 285-291, 301 forests, 294, 300 tundra, Fig. IX-16 food chain, Fig. IX-6 leaves, 288 world oceans, 236, 237 England, 185,390 air-sea systems, 53, 56, 57, 69, 77, 87, 106 environmental contamination, 361, 390 human adaptation, 374, 386 severe storms, 149 urbanization, 113, 117, 119 weather forecasting, 100 weather modification, 181 see also London, Eng. Environment alteration by volcanoes, 44 definition, 60, 373 design, 272-280 management, 283, 298 impact of technology, 338 Environmental Protection Agency, U.5., (EPA), 330, 331, 337, 344, 390 Enzymes high altitude adaptation, 382 plant growth and, 288 EPA, see Environmental Protection Agency, U.S. Equator climate, 165, 166, 167 drift of pollutants across, 190 dry zones meteorological observations, 187 magnetic, 10, 135 Pacific area drought prediction, 168 Erie Canal, 261, 262 Erosion after fire, 306, 308, 311 environmental management, 283 forests, 207, 208, 211, 214 tropical areas, 295, 296 lake aging, 268 precipitation augmentation, 177 steep slopes, 211, 212 surface water and, 204 Eskimos, 246, 376 Estuaries ecosystem, 248-253 marine productivity, 235, 243 storm damage, 133 Ethology, Animal: application to humans, 376 Ethylene, 320 Eugeosynclinal belts of rock, 31 Euler, Ferdinand K., 26 Euphausia superba, see Krill Euphausids, see Krill Europe agriculture, 291 air-sea system, 66, 86, 87 climatic change, 51, 52, 55, 57, 58, 68 data measurement, 59, Fig. IV-7 earth processes, 41 environmental contamination, 69, 193, 271, 343, 358 human adaptation, 374, 376 severe storms, 149 urbanization, 113, 114, 119, 226 Eutrophication, 209, 322 beneficial, 217 deforestation, Fig. IX-9 Great Lakes, 267-270 Lake Washington, 270-273 Evaporation effect on water supply, 198, 200, Fig. VII-2, 202 fog dispersal, 181 Lake Michigan, Fig. VIII-13, 259 Evapotranspiration, Fig. VII-1, Fig. VII-2 tropical forest, Fig. IX-10 Evolution, Cultural, 51, 377, 378 Exosphere, 11 Expendable Bathy-Thermographs (XBT), 87 Extreme ultra violet radiation, 4, 9, 10 F region of ionosphere, 9, 10 FAA, see Federal Aviation Administration, U.S. Farhi, Leon E., 389 Farming aerobiology and, 343 climatic changes and, 57, 58, 59 cultural pest control, 354 hail damage, 154 marketing specialists, 250, 251 precipitation, 177 slash and burn technique, 296, Fig. XI-3 subsistence, 218 see also Agriculture Faults, 30, 31 Fawbush, Ernest J., 101 Federal Aviation Administration, U.S. (FAA), 158 Feedback atmospheric temperatures, 56 causes of weather changes, 97 drought, 165 human ecosystem, 278 parasitic diseases and whole life of affected individual, 367, 369 pest-control technology, 350 pollution control by nature, 330 models, 340 precipitation mechanisms, 170, 171 sea-air rythms, 86, 87 see also Interactions 406 INDEX Fertility human populations, 377, 378 high altitudes, 383 soil, 40, 45 tropics, 295, 296, 297 Fertilization of forest areas, 208, 209 Fertilizers chemical, 278 human and farm sewage, 251 pollution effects, 323 runoff affecting water quality Great Lakes, 265, 268 rivers, Fig. VIII-15 FIDO, see Fog Investigation and Disposal Operation Finches, 302 Finger Lakes, N. Y„ 262 Finley, J. P., 138 Fire forest areas effects, 207, Fig. VII-5, 212, 213 fire ecology, 306-312 Isle Royale, 304 lightning-caused, 157, 158, 160, 161 slash burning, 208 incineration of wastes, Fig. X-2 spread of pollutants, Fig. X-16 Fish products, 239, 241 Fisher, R. A., 374 Fisheries aquaculture, 250-253 climatic changes and, 57, 58, 79, 82 ocean data collecting, 87 distribution throughout world, Fig. VIII— 7 food sources, 217 world ocean, 236-247 lakes, 228, 254, 273 Great Lakes, 261-267 Lake Michigan, Fig. VIII-14 leisure activity, 293 management models, 234 ocean floor sediments and, 362 Puget Sound, 248-250 purse seine, Fig. VIII-9 species selection for aquaculture, 250 water flow to the oceans, 200 Fishes adaptation to cold water, 232 effects of water pollution, 356, 359 in Great Lakes, 227 water quality required, 205, 206 see also names of specific species Fletcher, C. M., 390 Floods effect on water quality, 212 rain-caused, 128 tropical areas, 184, 296 Florida agriculture, 252, 253 air-sea system, 79 climatic change, Fig. II— 7, 57 data measurement, 68 ecosystems, 307 environmental contamination, 191, 194 severe storms, 135, 147, 189 weather modification, 166, 171 Florida Power and Light Company, 252 Florida Straits, 79 Flounder, 253 Fluid dynamics atmospheric circulation, 56 earth core studies, 22 lakes, 256 Fluid-flow instability in upper air: models, 106 Fluorescence quenching, 331 Fluorides, 320, 322 Fluorometer, 256 Flushing rates of lakes, 266 Fly-ash: pollution by, 358 Fog, 180-183 industry-induced, 337 urban-induced, 113, 114, 117 Fog Investigation and Disposal Operation (FIDO), 181 Food and Agriculture Organization, 299 Food chain, Fig. VIII-1, 234, 285, 286, Fig. IX-6, 289, 301 Antarctic, Fig. VIII-6 aquaculture, Fig. VIII-11 in Puget Sound, 248, 250 in sea, 236, 244 pollution from DDT, Fig. X-14, 359 pollution from petroleum compounds, 363 pollution from toxic metals, 322, 323 Food pyramid, see Food chain Food supply, World contaminants, 322 protection from, 217 losses to, 339 diseases of plants, 341 production fish, 228 potentials and problems, 215-218 world oceans, 233, 236, 237 projection, Fig. X-5 small number of crops and livestock, 217-218 sources forested areas, 302 tropical areas, 298 Food web, see Food chain Foraminifera, Planktonic, 53 Forest ecosystems, 292-301 animal ecology, 302-305 polluted precipitation and, 119 regeneration, 293, 297, 310 see also Fire Forest Laboratory, U.S., Missoula, Mont.; Riverside, Cal., 306 Forest management, Fig. VII-4, 205-212 land ownership, Fig. VII-4, 293 reforestation, 296 water quality and, 212-214 Puget Sound, 248 Forest Service, U.S. fire ecology, 306 forest lands, 205 lightning research, 160 monitored ecosystems, 283 watershed research, 294 Forests coniferous, 292, 308, 310, 337 deciduous, 295 comparison with rain forests, 299-301 serai stages, Fig. IX-1 fog benefits, 180 timber production, 292 tropical regions, 296, 297 fire and, 306, 307 trophic dynamics, 226 tropical, 292, 295-298 compared with temperate forests, 298-301 oxygen and, 34 rain forests, 295, 299-301, Fig. XI-3 Fort Tejon, Cal., 38 Fort Wayne, Ind., 114 Fossils fuels, 68, 71 lake sediment, 344 mammals, 73-74 Founder effect, see Genetic drift Fox, 304 France, 153, 154, 181, 183 Freeman, A. R„ 388 Freezing, Shock-induced: cloud seeding, 153 Freon fog-seeding nucleant, 180 air pollution, 357 Frequency management in radio communication, 14, 17 Fronts, Weather turbulence, 105 urbanization and, 113 Fuels toxic effects, 357-358, 360 see also Oil/Petroleum Fuginaga, Motosako, 251 Fujita, T. T., 130, 145 Fumaroles, 43 Fungi airborne, 340, 343, 345, 346 crop diseases, 341, Fig. X-8 fire and pine fungi, 306 in forest ecosystem, 292 G-6-PD deficiency, 365 Gaivoronskii, I. I., 151, 152 Game animals disease resistance, 217 forests, 293, 302-303, 305 Gamma globulin in tropical populations, 378 Gamma rays, 33 Gannon, John E., 227 GARP, see Global Atmospheric Research Program Gary, Ind., 119 Gas chromatography, 331 Gases, 67, 329, 337 air pollution, 339, 340, 357 in clean, dry air, Fig. X-l volcanoes, 40, 41, 43 Gasoline, see Oil/petroleum Gauging stations of U.S. Geological Survey, 197 Gaussian plume, 335, 336 Geiss, Johannes, 54 Genecology, 344 407 INDEX Generators, Ground-based for cloud seeding, 170, 175, 176 for fog-seeding, 180, 183 Genetic drift, 374, 383 Genetics gene pool, 278 high altitude populations, 383 pest control, 352, 354, 367 plant breeding in tropics, 297, 300 Geological Survey, U.S., 29, 45, 46, 197 Geomagnetic tail, 7, 8, 10 Geomorphic changes by hurricanes, 133-136 Geophysical Fluid Dynamics Laboratory, (NOAA), 66, 68, 82, 87 Georgia, 147 Geosphere, 301 Geosynchronous satellites see Satellites, Geostationary Geothermal heat, 33 German Atlantic Expedition, 187, 189 Germany agriculture, 215, 241 climatic change, 57 severe storms, 154 urbanization, 119 Glaciation atmospheric monitoring, 358, Fig. X-15, 360 boundaries, 52 causes, 52, 53, 54, 55 control of, 55 cycles, 62 ocean surface temperatures and, 53 volcanic activity and, 45 Global Atmospheric Research Program (GARP) data collection networks, 59, 88, 91, 95, 96, 97, 100, 101, 107, 126, 167, 190 monsoon forecasting, 184, 189 Global Network for Environmental Monitoring (GNEM) 235, 344 Global techtonics, 21-33 earthquakes and, 26, Fig. II— 3, 28, 35, 36 "Globigerina ooze," 53 Clomar Challenger, D.V. (ship), 53, 55 Glover, Kenneth M., 106 Glowing avalanches: damage by, 42 GNEM, see Global Network for Environmental Monitoring Goiter, 378-379 Gold deposits, 32 Golden Gate Park, Cal., 117 Goldfish in Great Lakes, 263 Goldman, Charles R., 272 Goldsmith, John R., 390 Goose Creek, Tex., 203 Grand River, Mich., 270 Grand Traverse Bay, Mich., 269 Grape growing, 352 Graphite, 22 Grassland Biome Project, Colorado (IBP), 344 Grassland ecosystem fire ecology, 306, 307 model, Fig. IX-2 blue gramagrass, Fig. IX-4 temperate regions, 298 tropical regions, 296 Graupel, 150, Fig. VI-6 Grazing practices effects of fire, 306 energy balance of a field, Fig. IX-7 environmental management, 283, 296 overgrazing forest lands, 210, 214 tundra, 313 Great Lakes circulation patterns, 82, 254-256 marine ecosystems, 225-228, 229, 230 pollution, 257, 259, 261-270, 272 Great Lakes Basin Commission, 268, 269 Great Lakes Deer Group, 303 Great Lakes Fishery Commission (U.S. -Canada compact), 2o6 Great Lakes Fishery Laboratory, U.S. Dept. of Interior, 266, 267 Great Plains, U.S. cereal-rust epidemiology, 339 drought studies, 219 hail storms, 149, 154 tornado models, 147 Greece, 35 Green Bay, Wise: lake pollution, 257, 263, 269 Greenhouse effect CO.- and, 82, 358 radiation balance of the earth, 70, 71 Greenland climatic change, 52, 53, 54, 55, 57 data measurement, 360 ice cap, 330 Gregg, Ian, 386 Gregory, K. F., 344 GROSSVERSUCH III, Canton Ticino, Switz., 152, 153 Groundwater levels, as part of water supply, 197, 204 Grouse, Ruffed: survival, 302, 303 Guiana, S. A., 33 Gulf Coast ocean systems, 81 severe storms, 133-135 Gulf of California, 33 Gulf of Mexico, 133, 135, 136, 147, 253 Gulf Stream, 78,79 Gunn, R„ 139 H Habitat research, 303, 306, 310 Hailstorms hailstones formation and growth, Fig. V-ll, 151 modeling, 154 hailstreak, 152 modeling, 149, Fig. VI-6 cloud modeling, 154 predictions, 94 suppression and control, 147 experiments, 151-154 HAILSWATH, Project, 153 Harbors pollution in, 223 debris in, 34 engineering models, 81 Hardwoods and pine forests, 308, 309, 310 summer fires, 311 tropics, 296 Hardy, Kenneth R., 106, 109 Harrar, J. George, 339 Hawaii earth processes, 27, 28 urbanization, 40, 41, 44 volcano technology, 35, 43, 45, 46 weather forecasting, 185 Hawaiian Volcano Observatory, 43, 45, 46 Hay fever, see Allergens, Airborne Hazards air pollution, 385, 386, 387 drought, 218 ocean pollution food sources, 244, 245 pest controls, 351, 354, 355 to aviation, 108, 180 toxic wastes in near shore regions, 233 water quality in forest areas, 207, 209 see also Radiation hazards Haze, 67, 68 air pollution, 192, Fig. X-6 assessed, 330-331 urban-induced, 117 Hazel, 311 Headfires, 310 Health effects of air quality on, 334, 337, 338, 349 biological contaminants, 33" see also Allergens, Airborne effects of smog and CO, 385-390 high altitude living, 379-385 see also Diseases; Hazards Heart diseases, 379, 380, 382, 384, 385 carbon monoxide and, Fig. XI-7, 390 Heat antarctic waters, 84 distribution in the atmosphere, 105 lightning, 157 relation to food intake, Fig. IX-8 storm forecasting, 138 see also Pollution, Thermal; Thermal bar; Thermal engine; Thermal plume in lake water Heat balance, see Solar radiation Heat effects, 324 fog modification, 181, 182 tundra ecosystems, Fig. IX-16 urban areas, 113, 116, Fig. IV-12 Heat transfer from earth's interior, 22 global circulation, 91 hurricanes, 125, 126, 128, 129, 131 ocean-air system, 78 Heathcote, John G„ 219 Hekla (volcano), Iceland, 41 Helicopters, 181 Helium, 10, 11, 51 Helmholtz, H. v., 109 Hemispheric interchange atmospheric circulation, 188 Herbicides forest areas, 205, 207 lake contamination, 272 2,4,5-T hazard, 351 408 INDEX Herbivores, 74 balance of nature, 280, 285,286 forest ecology, 302-305 trophic dynamics, 225, 226 marine, 237, 239 see also Game animals; Livestock Herculaneum (historic), 40 Heredity adaptive traits, 383 high altitude, Fig. XI-4 Herring, 238, 363, 264 Heterozygosity, 373, 374 Hewlett, John D., 211 Hicks, Steacy D., 10" High Altitude Hydrometeorological Service, Nalchick, U.S.S.R., 151, 152 High Plains, U.S., 154, 204 Hilo, Hawaii, 41, 46 Himalaya Mts., 184, 186 HIRS (High Resolution Infrared Radiometers), 69 Hoecker, W. H., 140 Holland, Joshua Z., 82 Holography: fisheries management, 244 Homozygosity, 373 Honolulu, Hawaii modeling, 185 oceanographic cruises, 87 Hoof-and-mouth disease, 370 Hormone pesticides, 351 Horn, Ralph, 361, 362, 363 Horse: energy budget, Fig. IX-7 Houghton, Henry G., 183 Housing: disease control in Latin America, 370 Housing and household agents polluting effects, 327, 385, 387 Hubbard Brook, N. H., 208, 293, Fig. IX-9 Hudson River, 262 Human factors aggression, 376 air quality standards, 337 food chain, 225 forest ecosystems, 301 incidence of fires, 307 geomorphic coastal changes, 136 impact on environment, 223, 277, 334, Fig. X-S in climatic change, 58, 59, 63-64, 65, 67, 68, 69, 70-71, 101 in storm forecasting, 138 volunteer spotters, 147-148 in weather forecasting, 97, 99, 102, 104, 165 tropical areas, 185 labor in agriculture, 216 water quality, 211, 212, 213 water supply, 198, 218 see also Adaptation: human; Pollution, Atmospheric: man-made Humboldt Current, lo7 Humidity cloud formation and, 165 fog modification, 181 forest fires, 306, 307 in atmosphere, 178 plant growth, 287, 288 prescribed burning, 310 tropical forests, 295 urbanization and, 113 water cycle, 200, 201, 202 Hungary, 33, 216 Humphrey, Robert R., 306 Hunt, James L., 201 Huntington Beech, Cal., 203 Hurricane Alix (1960), 134 Hurricane Audrey (1957), 134, 136 Hurricane Betsy (1965), 127 Hurricane Beulah (1967), 123, 124 Hurricane Camille (1969), 127, 133, Fig. V-5, 136 Hurricane Carol (1954), 133, 135; (1960), 134, 135 Hurricane Debby (1969), 126, 128, 129, 130 Hurricanes, 123-136, 191 effect on water quality, 212 forecasting, 94, 95, 98, 102, 103 models for, 91 modification eye-wall seeding, 146 see also STORMFURY, Project role in tropical weather, 188, 18" Hutchinson, G. Evelyn, 254 Hutton, James P., 22 Hydrochloric acid: volcanoes, 43 Hydrofluoric acid: volcanoes, 43 Hydrogen, 10, 12 atomic in thermosphere, 11 earth's mass, 51 fluoride, 342 ion activity, 212 sulfide air pollution, 320 volcanoes, 43 Hydrologic cycle, Fig. VII-2 Hydrology, Stochastic, 197-198 Hydrosphere, 3 circulation in, 301 Hydrothermal pollutants, 321 Hygroscopic particles seeding cold clouds, 175 seeding warm clouds, 174 seeding warm fog, 181, 182, 183 Hypoxia: in high altitudes, 381,382,384, 385 H.V.O., see Hawaiian Volcano Observatory I Ibadan, University of, Nigeria, 185 IBP, see International Biological Program, U.S. Ice ages, 32, 120 cores analysis, 58 atmospheric lead, 330 crystals formation, 192, 193 precipitation formation, 174, 182 structure, Fig. VI-3 fogs (Alaska) modification, 181, 182 tundra, 313 Ice-seals, 246 Iceland air-sea system, 8o climatic change, 52, 57, 72 earth processes, 27, 33, 41, 47 ICSU, see International Council of Scientific Unions Idaho, 29, 31 IDOE, set' International Decade of Ocean Exploration Igneous rocks, 30 IGY, see International Geophysical Year Illinois, 31, 216, Fig. VIII-15 Illile ice nuclei, 192 in ocean sediments, 358 Immunofluorescence malaria diagnosis, 366 Imperial Valley, Cal., 33 Inbreeding, 374, 378 India agriculture, 217, 218 earthquake prediction, 37 hailstorms, 149 monsoons, 184, 186 see also Institute of Tropical Meteorol- ogy; National Council of Economic Advisors see also Rajasthan Desert Indian Ocean air-sea system, 78, 82, 84, 167 expedition, 82 severe storms, 134, 184 water resources, 236 Indians, American, 379, 384 Indonesia aquaculture, 238 data measurement, 86 earth processes, 35, 40 monsoon forecasting, 184 urbanization, 43, 44 Indoor environments: aerobiology, 343 Industrial revolution, 113 Industry effect on water quality, 199, 213, 214, 337 radiation damage, 323, 325 see also Pollution, Industrial; Pollution, Thermal Inertia: tornado modeling, 140 Infrared radiation heat balance of the earth and, 287 spectrometry, 141 weather predicting, 103 Inland waterways, 82, 265 Insecticides Chagas' disease, 369, 370 effect on terrestrial ecosystems, 301 forest areas, 207 malaria transmission and, 364-367 phytoplankton sensitivity to, Fig. VIII-3 Insects air pollution, 339, 340, 341, 343, 345 pesticide resistance, Fig. X-ll population model, 353 problem of agriculture, 216, 217 tropical plants, 297, 298 see also Malaria Institute for Atmospheric Physics, National Research Council, Italy, 153 409 INDEX Institute of Marine Sciences, University of Miami, 253 Institute of Tropical Meteorology, Poona, India, 185 Instrumentation animal ecology, 302 atmospheric circulation, 90, 334 balloon-borne, 90, 98, 190 climatology, 108 fisheries management, 244 forest ecosystems, 300 fire ecology, 307 hail research, 156 infrared thermometer, 256 ocean characteristics, 78, 80, 87 photomonitoring equipment for antarctic waters, 233 physical limnology, 255, 256 severe storms, 95, 132, 147 tropical region studies, 188 urban effects on weather changes, 114, 115 weather modification, 170, 175, 176, 178 weather observations, 106 weather predictions, 103, 104 Insurance: hail damage, 154 Intelligence testing, 376 Interactions air pollutants, 342, 343 atmosphere and its lower boundary, 89,91, 97, 101 crust and mantle, 21 fire studies, 307 Great Lakes fish species, 264 man and fisheries, 263 heat balance of the earth and photosynthesis, 287 host-parasite insects, 364,366 hurricane formation, 125, 126, 128, 131 insect species and pesticides, 352 lake water mixing, 254 internal waves and turbulence, 256 man and climate, 57, 115, 177 drought, 218 smog, 390 marine biological system and its environment, 233 ocean-atmosphere, 77-88 contaminants, 359 rainfall, 165, 167 pollution control and economic system, 334 Puget Sound, 248, 249 radioactive species, 358 sea floors and continental margins, 29 submodels developed separately, 282 temperate forests animals and environment, 303 water-nutrient cycles, 294 tropics, 187 temperature and rainfall, 295 vegetation and environment, 301 vegetation and water cycle, 298 tundra ecosystems, 313, 314 waste disposal and conservation, 338 Interdisciplinary problems, see Multidisciplinary problems Interglacial periods, 53, 54, 55 Interior, U.S. Department of, Fig. VI-11, 266, 267 see also Great Lakes Fishery Laboratory International Biological Program, U.S., (IBP) aerobiology program, 339, 341, 342, 344 ecosystem studies, 58, 233, 279, 283, 289, 294, 300, 314, 344 human adaptation, 379, 380 International Council of Scientific Unions (ICSU), 80 Global Atmospheric Research Program (GARP), 91 International Union of Biological Sciences, (IUBS), 344 International Union of Geological Sciences (IUGS), 31 Inter-Union Commission on Solar- Terrestrial Physics, 15 Scientific Committee on Ocean Research, 80 International Decade of Ocean Exploration (IDOE), 82, 88, 167 International Geophysical Year (IGY), 88, 190, 340 International Hydrological Decade, 294 International Hydrological Program, International Field Study, 270 International Joint Commission (Can.-U.S.), 267 International Reference Center on Air Pollution (WHO), 388 International Union of Biological Sciences see under International Council of Scientific Unions International Union of Geological Sciences see under International Council of Scientific Unions Intertropic Convergence Zone, 194 Invertebrates: relationship of food and heat, Fig. IX-8 Iodine, 118, 378 Ionization: created by radiation from sun, 9 lonosondes, 15 Ionosphere, 3, 5, 8-11, 13-14, 17 electric field from earth, 158 storms, 10 Irazu (volcano), Costa Rica, 42, 43 Iribarne, J. V., 151, 152 IRIS (Infrared Interferometer Spectrometer), 90 Iron, 35 content of dust over tropics, 193 deposits, 32 earth's core, 23 lake nutrient, 272 oxides, 295 Irrigation health hazard, 217 in agriculture, Fig. VII-8, 220, 221 tropical regions, 296, 297, 298 water from Great Lakes region, 265 water use, Fig. VII-1, 204, 291 Isle Derniere, La., 135 Isle Royale ecosystem, 303-305 Isotopic studies core samples, 55, 57 lead, 30 oxygen 180, 53 sea water, 84 strontium, 30 Italy, 153 earth processes, 33, 44, 53 human adaptation, 388 Ivory Coast, Africa, 192 Tagger, Thomas, 45 Japan aquaculture, 238, 241, 242, 251, 252 earth processes, 30, 35, 37, 43, 44, 135 environmental contamination, 334, Fig. X-12, 357, 363 human adaptation, 374, Fig. XI-2 oceanographic research, 240 weather prediction, 45, 100 Japanese Meteorological Agency, 81 Java, 41, 43,44 Jet streams hailstorms, 149 heat distribution in the atmosphere, 105 low-level, 108 pollution transport, 357, 358 prediction of, 93, 94 subtropical, 86, 189 Jones, Donald, 218 Jones, H. L„ 139 Kailua-Kona, Hawaii, 44 Kamchatka Peninsula, Russia, 40 Kansas, 216 Kaolinite, 192, 358 Kapaho, Hawaii, 44 Kartsivadze, A. I., 151, 152 Kaskaskia River, 111., Fig. VIII-15 Kates, Allan H., 219 Keeling, Charles D., 330 Kelp, 240 Kelut Volcano, Java, 42, 43 Kelvin-Helmholtz waves, 109, 110, 111 Kelvin type waves, 255 Kenya, Fig. V-12 Kericho, Kenya, 153 Kilauea Volcano, Hawaii, 40, 43, 44, 45, 46 Kimura, Kazuo K., 374 Kinzer, G.D., 139 Kiska Volcano, Aleutians, 46 Kitumbe Estate, Kenya, 153 Kodiak, Alaska polar ecosystems, 314 volcanic ash, 41 Komarek, Edwin Vaclav, 307 Koppen, Wladimir, 54 Krakatoa Volcano, Sumatra, 41, 44, 45 Krill in food chain, 232, 237, Fig. VIII-6, 240, 241, 242 Kung, Ernest C, 105 Kuo, Hsiao-Lan, 82, 140 Kuroshio Current, 79, 244 Kutzbach, John E., 72 410 INDEX La Jolla, Cal.: oceanographic cruises, 87 La Porte, Ind., 11° Lactase deficiency, 376 Lahars, see Mudflows Lake Erie circulation patterns, 254 pollution, 262-268, 272, 273 urbanization, 226 Lake Huron, 262, 263, 265, 266, 267, 268 Lake Maracaibo, Venezuela, 203 Lake Michigan, 227, 228, 257, Fig. VIII-13, 259, Fig. VIII-14, 262, 263, 264, 265, 266, 267, 268, 270 Lake Ontario, 255, 261, 262, 263, 264, 265, 266, 267, 268, 270 Lake St. Clair, 263, 266 Lake Superior, 257, 262, 263, 264, 265, 266, 267, 268, 304 Lake Tahoe, 272 Lake Victoria, Africa, Fig. Ill— 1 , 52, 72, 220 Lake Washington, 270, Fig. VIII-16, 272, Fig. VIII-17 Lakes, 294, 344 contaminants, Fig. X-14 dynamics of, 254-260 Laki (volcano), Iceland, 41 Lamb, H. H., 72 Land Grant College system, 218 Land surface: world total, 299 Land use affected by climatic changes, 72, 73 arable areas and world population, Fig. VII-8 droughts and, 167, 220 effects of changes in, 34 forest ecosystems, 294 urbanization and, 278 water quality and, 205, Fig. VII-7, 213 Landslides, 212 Langmuir, Irving, 154, 183 Langmuir spirals, 226 Larval ecology, 231 Lasers, 112, 194 Lassen Peak, Cal., 40 Latin America, 215, 370 Laurel forest, 298 Lava, 22, 27, 40-43 evidence of earth's magnetic field reversals, Fig. II— 2 water storage, 203 Leaching of minerals tropical forests, 295, 296 Lead iodide (PbL), 118, 151, 152, 174 isotopic studies, 30 poisoning, 322, 327, 360 pollutants in the air, 320, 330 content of dust, 193 urban-produced, 118 toxic waste in lakes, 272 Legal implications building codes hurricane protection, 136 hurricane modification, 132 precipitation management, 173, 178 Leisure science, 280 see also Recreation and leisure time Liberia, Fig. XI-3 Lichens: tundra, 313, 314 LIDAR (Light Detection and Ranging), 58, 112, 147, 194 Life support systems, see Food chain Lightning, 157-161 light from, 157 research, 158-159 tornadoes and, 138 Likens, G. E„ 294 Lilly, D., 140 Limestone, 203 Limnology, 254 Great Lakes, 26" Lake Washington, 273 List, R., 150, 151, 152 Lithosphere, 3, 29 Liverworts, 292 Livestock effect on water quality, 210, 214 for western ranges, 74 horse energy budget, Fig. IX-7 protection against malaria, 367 see also Herbivores Loblolly pine forests, 308, 310 Lodge, J. P., 330 Lominadze, V. P., 152 London, Eng., 53, 113, 117, 386, 390 Lone Pine, Cal., 38 Long Beach, Cal, Fig. VII-3 Lorenz, Edward Norton, 63, 120 Lorenz, Fred W., 376 Los Angeles, Cal. air-quality models, 336 destructive earthquakes, 38 environmental contamination, 337, 388, 390 fog disposal operation, 181, 182 Louisiana fire ecology, 308 severe storms, 133, 134, 135, 136, 147 Lozowski, E. P., 152 Lubbock, Texas, 204 Lubec, Maine, 135 Ludlam, F. H., 109 Lumbering and logging water quality and, 210, 213 fire and, 308, 310 Lung disease and functioning high altitudes, 381, 382 see also Pulmonary edema Lunn, J. E., 388 Lynx, 304 Lysimeter studies, 209 M Macdonald, Eleanor Josephine, 366 Machta, Lester, 64 McMurdo Sound, Antarctica, 232 Magma, 40, 43, 48 Magnetic field of the earth, 21 core and, 3, 23 earthquakes and changes in, 37 reversals, Fig. II— 2, 25, 27, 28 study of, 5 Magnetic fields: interplanetary, 4, 6 Magnetite-chalcopyrite, 31 Magnetopause, 3, 7 Magnetosheath, 3, 7 Magnetosphere, 3, 5, 6, 7-8, 9 Maine, 118 Malaria, 364-367 control and eradication of animal diseases, 217 DDT and 352 resistance to, 376 see also Sickle cell anemia Malaya, University of Kuala Lumpur, 185 Malaysia, 238 Mammals extinct types, 73, 74 marine, 239, 240-241, 245, 247 Mammauthus columbi, (extinct mammal), 73 Manabe, Syukuro, 64, 67, 69, 87 Manam Volcano, New Guinea, 43 Manganese deposits, 32 Manpower air pollution research, 334 interdisciplinary training environmental designs, 285 training air-sea studies, 79, 82, 101 aquaculture, 251 pest control, 353, 356 malaria, 367 tropical meteorology, 185, 188 Mantle of the earth, 21, 23, 26-34 see also Earthquakes; Sea floor: spreading Maps, climatic anomalies, 88 Mariculture, see Aquaculture Marine invaders, Great Lakes, 262-263 Marketing specialists, see Farming Marten, 304 Martinique, West Indies, 42, 44 Maryland, 308 Masaya (volcano), Nicaragua, 43 Massachusetts Institute of Technology, 183 Materials changes, due to stresses, 36 Mauna Loa (volcano), Hawaii, 41, 44, 46, 64 Mauritius Island, Indian Ocean, 134, 135 Measurements aerobiology, 340, 345-349 air quality, 331, 333, 334 crustal velocity, 29 sea-air movements, 100 sound wave propagation, 112 windborne dust tranport, 191, 193 urbanization and weather changes, 115 Medical problems high altitudes, 379-385 tropics, 364-370 see also Diseases Mediterranean Sea air-sea system, 86, 106, 109, 254 earth processes, 35, 44 Mendel, Gregor, 373 Merapi Volcano, Java, 42 Mercaptans, 320 Mercury, 272, 322, 357 Mesopause, 11 Mesosphere, 3, 11, 12 Mesozoic era, 29, 30, 31, 55 411 INDEX Mesquite: fire and. Fig. IX-13 Metabolism at high altitudes, 381 heart disease, 388-389 Metaldehyde, 174 Metallogenic maps for North America, 31 Metals: to\ic effects, 322, 357 see also specific names Meteoric material in ionosphere, 10 Metropolitan Problems Advisory Committee, Seattle, Wash., 271 Mexico, 74, 147, 358 Mexico City, Mexico, 204 Miami, Fla., 191, 194 University of, 253 Mice, see Rodents Michigan, University of, 269 Microfossils, 344 Microminiaturization equipment for weather research, 104 Micropaleontological analysis of core samples, 53 Mid-Atlantic Ridge, 26, 27 Mid-Ocean Dynamics Experiment (MODE), 80 Middle East, 280 Midwest (U.S.) animal ecology, 303 atmospheric dust, 192 climatic change, 69 cyclone defense, 135 lake pollution, 271 Migration: marine mammals, 246 Milankovitch, M., 54 Milkfish, 251 Miller, Robert C, 101 Millet, 289 Minerals forest soils, 296 mining, 214 prospecting, 28, 30-32 Mining of water, 204 Ministry of Agriculture and Forests, Italy, 153 Minnesota, 302, 311 Minoan civilization, (Crete), 44 Mintz, Yale, 88 Mississippi Valley, 31, 38, 147 hurricanes, 133, Fig. V-5, 136 Missouri, 31, 38, 170 Mites: pesticide resistance, Fig. X-ll, 352 Mitochandria, 288 MODE, see Mid-Ocean Dynamics Experiment Models, Laboratory lakes, 254, 269 lightning, 159, 160 tornadoes, 140, 141, 146 urban-induced weather change, 119 Models, Mathematical air pollution, 334, 340, Fig. X-7, 335-336 antarctic marine life, 232 atmosphere-ocean systems, 58, 59, 64, Fig. IiI-6, 68, 70 atmospheric circulation, 89-91 forest ecosystems, 293, 294, 295, 299, 300, 301, 307 animal-habitat relationships, 303 hailstorms, 149, 150, 154 heat-food relationships of invertebrates, Fig. IX-8 lake circulation, 255, 269, 270 lightning behavior, 159 ocean currents, 79, 80, 81, 82-83, 87 pest control, 353, 366, 369 physical, economic and social relationships, Fig. X-5 plant-energy exchange, 287, 288 tundra ecosystem, 314, Fig. IX-16 volcanic activity, 46, 47 weather modification, 174, 175, 176, Fig. VI-6, 178, 181, 182 Models, Predictive cloud seeding, 171, Fig. VI-3 drought, 167, 168, 220 for estimating water supply, 197, 198, 201, 202 for weather forecasting, 104, 114-115 dynamic-iterative, 96, 98, "9, 100, 106 statistical-physical-synoptic, 100 tropical meteorology, 185, 186, 187, 188, 189 hurricane, 95, 124, 125, 126, 128, 129, 131, 132 lake circulation, 254 solar activity and geophysical response, 16-17 tornado, 139, 140, 141 trophic dynamics of Puget Sound, 249 watershed research, 211 Models, Simulation ecosystems, 281, 282 grassland, Fig. IX-2 mosquito submodel, Fig. IX-3 oceans, 233, 234, 235, 244 validation studies, 283, Fig. IX-4 Great Lakes, 269 upper atmosphere, 3, 14 volcanic processes, 46-47 watershed management, 211 Models, Submodels ecosystems, 281, Fig. IX-3, 284 Mohorovicic discontinuity, 29 Mojave Desert, Cal, 29, 204 Molds air pollution, 339, 343 crop diseases, Fig. X-8 Mollusks: aquaculture, Fig. VIII— 11 Molybdenum, 215 Monitoring air pollution, 331 climatic changes, 51, 58, 68 ecosystems forest fires, 307 model validating, 283, Fig. IX-4 for atmospheric contaminants, 337 Great Lakes water quality, 264, 266, 270 tornadoes, 138, 140-141 volcanoes, 44, 46, 48 weather stations, 137 Monocultures domesticated plants and animals, 278 tropical regions, 297 Monsoons, 184-187, Fig. VI-10, 220 Montana, 31, 160, 306 Monte Nuovo (volcano), Italy, 43 Montmorillite, 192 Monzonite, 29 Moon, Fig. 1-3 Moose, 303-305 Moreno, Eudoro, 306 Morgan, B., 139 Morris, Dale Duane, 376 Mortality rates, see Death rates Morton, Newton E., 373, 374 Mosquitos: submodel, Fig. IX-3, 364-367 Mosses in forest ecosystem, 292 tundra, 313, 314 Motor vehicles: air pollution, 319, 385, 390 Mount Agung, Bali, 56, 68 Mount Baker (volcano), Wash., 44 Mount Katmai (volcano), Alaska, 41, 44 Mount Lassen (volcano), Cal., 40, 44 Mount Mazama (volcano), Ore., 40 Mount Pelee (volcano), Martinique, 42, 44, 45 Mount Ranier (volcano), Wash., 44 Mount St. Helens (volcano), Wash., 44 Mount San Salvatore, Switz., Fig. V-14 Mount Shasta (volcano), Cal., 44 Mount Wilson, Cal., 41 Mountain sickness, 382, 384, 385 Mountainous regions: clear air turbulence over, 106 Mudflows, 207 volcanic, 42-43 Mueller, Peter Klaus, 388 Muller, H. J., 373 Multidisciplinary problems environmental design, 279 Hubbard Brook Ecosystem Study, 293-295 human biology evolution, 378, 384 Museums, 231 Mussels, 241, 251 Mutations, 338, 373 Mysids, 238 N Nairobi, University of, Kenya, 185 Namias, J., 166, 167 Naples, Italy, 43 NAS, see National Academy of Sciences, U.S. NASA, see National Aeronautics and Space Administration National Academy of Sciences, U.S. (NAS), 91 see also National Committee for Clear Air Turbulence National Aeronautics and Space Administration (NASA), 47, 69, 112, Fig. VI-11 National Bureau of Electrical Energy, Italy, 153 National Center for Atmospheric Research (NCAR) BOMEX support, Fig. VI-11 environmental contamination, 330 modeling, Fig. Ill— 6, 66, 68, 235 National Committee for Clear Air Turbulence, U.S., (NAS), 108 412 INDFX National Council of Economic Advisors, India, 217 National Hail Modification Program, (NSF), 155 National Hail Research Experiment (NHRE), (NSF), 151, 155, 156 National Hail Suppression Field Test, (NSF), 153, 155 National Hurricane Center, (NOAA), 125 National Hurricane Research Laboratory, (NOAA), 130 National Marine Fisheries Service, (NMFS), (NOAA), 87, 253 National Maritime Commission, U.S., 189 National Meteorological Center, Wash., D. C, 139 National Oceanic and Atmospheric Administration (NOAA), 13, 16 modeling, 66, t>8, 81, 82, 87 project STORMFURY, 128 see also Geophysical Fluid Dynamics Laboratory; National Hurricane Center; National Hurricane Research Labora- tory; National Marine Fisheries Service; National Severe Storm Forecast Center; National Severe Storms Laboratory; National Weather Service; Space Environment Laboratory National Park Service, U.S., 304 National Science Foundation (NSF), Fig. VI-11 see also National Hail Modification Program; National Hail Research Experiment; National Hail Suppression Field Test National Severe Storm Forecast Center, (NOAA), 138 National Severe Storms Laboratory, (NOAA), 138, Fig. V-8 National University, Taipei, Taiwan, 185 National Weather Service, (NOAA), 81, Fig. IV-9, 102, 103, 136, 138, 141, 168, 171, 197 Natural enemies of pests, 350, 351, 352, 353, 354, 355, 356 Natural factors in climatic change, 63, 64 contaminants, 329, 330 Natural gas, 33, 357 Natural selection, 72, 373-378, 383 pests and pesticides, Fig. X— 11, 354 Naval Electronics Laboratory Center, San Diego, Cal., 109 Navy, U.S., 81, 102, 128 NCAR, see National Center for Atmospheric Research Negro, 376, 377 Nepal, 379 Nephelometer, 330 Netherlands, 339 Nevada, 29, 31, 204 New England data measurement, 31 drought, 165 severe storms, 133 urbanization, 119 New Guinea, 43 New Hampshire, 293 New Jersey, 336 New Mexico, 31, 74, 204 New Orleans, La., 135 New York, 38, 53, 119, 336, 362 New Zealand, 33, 35, 44, Fig. VII-8 NHRE, see National Hail Research Experiment Niagara falls, 262 river, 254, 255 Nicaragua, 43 Nickel sulfide ores, 31 Nigeria, 192 Nile River, 296 Nitrogen as fertilizer in agriculture, 215 in forest areas, 209 cycles, 282 enrichment of lake waters, 226, 228, 268, 272 Lake Washington, Fig. VIII-17 forests, 300 in soil of tropical forests, 295 in the air, 329 nitrogen oxides air pollution, 320, 337, 388, 390 contaminants, 322 in groundwater, 200 in Lake Washington, 272 in rivers, Fig. VIII— 15 mesophere, 12 Nitrogen fixing burned-over soils, 310 Nitrogen-fixing plants, 208 trophic dynamics, 227 NMFS, see National Marine Fisheries Service, U.S. NOAA, see National Oceanic and Atmospheric Administration Noise and vibrations: effects of exposure, 326 North America air-sea system, 86 climatic change, 53, 55, 57, 73 drought, 167 earth processes, 30, 31, 35, 44 ecosystems, 286 pollution, 267 severe storms, 160 urbanization, 226 water resources, 291, 294 weather forecasting, Fig. IV-9, 115, 119 North Carolina, 309 North Sea, 33, 79, 81 Northern hemisphere climatic change, Fig. Ill— 4, 61 monsoon winds, 184 temperature variation, Fig. Ill— 8, Fig. III-9, Fig. 111-10 weather forecasting, 90, Fig. IV-7, 98, 101 Norway, 78, 241, 246 Norwegian Sea, 78, 102, 103, 104 NSF, see National Science Foundation Nuclear reactors effects on water quality, 231 estuaries, 248 lakes, 259, 268 oceans, 245 see also Heat; Power Nucleating agents, 174 cloud seeding, 176 effect on hurricanes, 191, 193 fog dispersal, 180, 181, 182, 183 1,5-dehydroxynaphthalene, 174 see also Ice: crystals; Silver iodide Nuclei condensation, Fig. X-6 freezing, 117, 118, 174 hygroscopic, 153 ice, 153, 170, 171, Fig. VI-7, 181, 182, 193 precipitation, Fig. VI-2, 170, 329 see also Cloud seeding Nuees ardentes, see Glowing avalanches Nufioa Indians, Fig. XI-6 Nutrients forest ecosystem, 292, Fig. IX-9, 295, 301,311 Great Lakes, 269, 270 Lake Washington, 271, 272 tundra ecosystem, Fig. IX-16 Nutrition human, at high altitudes, 382, 383, 385 plant crop production, 215 forest streams, 208, 209 phytoplankton, 234 requirements for aquaculture, 251 Nyamuragira Volcano, Africa, 44 Oasis effect: water cycle, 202 Observatories for solar activities, 15, 17 seismographic stations, 23 Ocean-atmosphere system, 77-120, 287 BOMEX project, 125 drought prediction, 165 marine contamination in, 357-360 models, 65-72 monsoons, 186 phytoplankton and, 233 weather forecasting and, 101 Oceanography, 254 role in weather forecasting, 82, 100 Oceans basins, 26 COj sink, 358 circulation, 77-88, Fig. IV-2, Fig. IV-3, 234 models, 68 currents, 78, 79, 83, 84 floor Globigerina ooze, 53 oil on, 362 formation, 21, 24 heat sink, 257 source of carbon monoxide, 330 surface, 52, Fig. III-2, 58, 64, 100 thermal pollution, 34 tropical areas, 189 weather predicting over, 96 Ogallala Formation, 204 Ohio, 69 413 INDEX Oil from marine animals, 240, 241, 242 Oil/petroleum gasoline vaporization, 357 prospecting Alaska, 32 continental shelves, 28 flow of wells, 47 worldwide, 31, 33 sea floor contamination, 361-363 subsidence of rock formations, 203 water pollution, 322 effect on marine mammals, 245 O'Keeffe, Andrew E., 330 Oklahoma, Fig. V-7 Olivine in mantle, 29 Omnivores: food chain, 286 Opik, Ernst, 52 Oregon, 40, 204 Organophosphorus compounds, 355 Orinoco River, SA., 300 Orographic clouds, 175 Orographic lifting and tilting, 111 Orville, H. D., 150 Ostracods, Fig. VIII-5 Ottersten, Hans, 106 Overgrazing, see Grazing practices Owens Valley, Cal., 38 Owl monkey, 365 Owls, 302 Oxidation carbon monoxide, 358 floating oil lumps, 362 of soil humus, releasing CO:.-, 71 Oxides, 319, 333 Oxygen atomic in mesosphere, 12 in thermosphere, 11 consumption by biosphere, 286 forest ecosystem, 301 from plants, 287, 288 human consumption at high altitudes, 379, Fig. XI-4, Fig. XI-5, 382 newborns, 384 in atmosphere 34, 320, 329 in forest streams, 206 in lakes, 263, 264, 268, 270 in Lake Washington, 271 in ocean water, 83, 84, 233 antarctic, 232 in the blood, 387 oxygen isotope (lsO) ice-caps of Greenland, 57 in foraminiferal shells, 53 in sea-core dating, Fig. II 1—3 Oyster-farming: U.S., 252 Ozone (O:,), 11, 12 in atmosphere, 89, 319, 320 health hazard, 387, 388, 390 urban areas, 117 in stratosphere, 55, 58, 287 monitoring, 69 volcanic gases and, 41 P-waves, 29 Pacific Northwest, 209 Pacific Ocean air-sea system, Fig. 1V-1, 78, 83-87, 165, 167, 358 coral reefs, 232 data measurements, 79, 81, 98, 100 earth processes, 28, 30, 31, 35, 37, 38, 45 environmental contamination, 367 severe storms, 123, 189 water resources, 233, 236, 242, 244 weather forecasting, 101, 168 PAHO, see Pan American Health Organization Paleozoic era, 31, 52 Pan American Boeing 707, 158 Pan American Health Organization (PAHO), 379, 380 Panama City, Fla., 253 Panofsky, Hans A., 105 Paraffins, 361 Parameterization cumulonimbus convection, 189 hurricane modeling, 126, 128 Parameters animal ecology, 302, 304 ecosystem modeling, 282, 283 forests, 300, 301 hydrological fisheries, 242, 249 ocean circulation, 234 physico-chemical, 340 Great Lakes, 227, 266 statistical water cycle, 198, 201, 202 Parasites in forest ecosystem, 292 malaria-spreading, 364, 365 world ocean mammals, 245 Paricutin Volcano, Mex., 41 Particulates air pollutants, 319, 333, 337, 339, 385, 387, 388, 390 radionuclides, 340 see also Aerosols Patagonia, S.A., 53 Pate, John B., 330 Patterson, Claire C, 330 Pauli, Hannes, 388 Pawnee site, 284 PCB (Polychlorinated biphenyls) in fish, birds and mammals, Fig. X-16 in fish in lakes, 228 in oceans, 233, 359 Penguins, 232, 241 Penman, H. L., 201 Pennsylvania, Fig. VI-8, Fig. X-2 Perch, 261, 263 Perchloroethylene, 357 Peridotite in mantle, 29 Permutt, Solbert, 389 Persistence adsorption of pollutants, 291 drought-producing systems, 165 forecasting, 99, 102 pesticides, 352, 356, Fig. X-16 water contamination in forest areas, 206 water currents in lakes, 255 Peru, 234, 379 Pesticides, 350-356 effect on food chain, 244, 245, 323 effect on terrestrial ecosystems, 301 effect on water quality forest areas, 206, 207 Great Lakes, 264, 265 lake eutrophication, 268 pollution effects chlorinated hydrocarbons, 320, 322, 333, 359 phosphorus, 321 2,4,5-T, 207, 213 see also Insecticides Pests, 350-356 see also Insects; Pesticides Petroleum, see Oil/petroleum Petroleum hydrocarbons: marine contaminants, Fig. X-17 Petrology, 46, 47 Pharmacological properties of tropical trees, 298 Phenology of plant species, 289 Phenols, 322 Phenotypic selection in crop-breeding, 216 Phenoxy herbicide, 207 Philippine Islands conservation, 251 earth processes, 35, 44 environmental contamination, 367 research facility, 185 Philippines, University of the, 185 Phlegrean Fields, Italy, 43 Phloroglucinol cloud seeding nucleant, 174 fog seeding nucleant, 180 Phosphates contaminants, 322 Lake Washington nutrient, 271 Phosphorus enrichment of lake waters, 226, 228, 272 excess in Lake Erie, 264 forests, 296, 300 Great Lakes, 268 Lake Washington, Fig. VIII-17 Phosphorus-fixing mineral soils, 209 trophic dynamics, 227 Photochemistry air pollution, 385 ionosphere, 10 plant growth, 288 Photosynthesis aquatic plants, 225, 226, 236 evolution of processes, 34 Lake Washington, 272 life support systems and, 285, 286 marine contaminants and, 359 modeling, 282 plant energy exchange, 287, 288 tundra ecosystem, Fig. IX-16 Phytogeography, 344 Phytoplankton, Fig. VIII-4 absorption of nutrients, 234 in aquaculture, Fig. VIII-11 in lakes, 226, 227 in oceans, 233, Fig. VIII-6, 359, 361, 362 sensitivity to insecticides, Fig. VIII— 3 Pike, Blue, 261, 263 414 Pine trees, 310, 311 air pollutants and, 337 Bristlecone, 61 Loblolly, 308, 310 Longleaf, 306 Shortleaf, 308 Piscivores, 227 Pitts, Grover C, 390 Planktivorous fish, 227, 228 Plankton, 53, 231, 340, 344 see also Phytoplankton; Zooplankton Plant-water relationships, 219-220 Plants aerobiology and, 343 antarctic, 313, 314 aquatic, 236 arctic, 314 diseases, 341, Fig. X-8 food chain, Fig. IX-6 food production, 216 growth, 288, 289 leaves, systems analysis, 289 spore reproduction, Fig. XI-1 Plasma physics, 3, 5, 8 Plasmapause, 8 Plate techtonics, see Global techtonics Pleistocene era, 62, 73, 74 Pliocene age, 204 Plum Island, Mass., 133, 135 Polar bear, 377 Polar caps absorption, 11, 14 magnetopause, 7 Polar front zone, 84 precipitation, 165 Polar regions ecosystems, 313-315 effect of aerosols, 68 floating oil, 362 ice melting possibilities, 119 information lack on magnetopause over, 7 ionosphere and, 10 radio communication over, 11, 14-15, 17 shipping in, 82 soil studies, 291 see also Antarctica; Arctic regions Polar wind: in F region of ionosphere, 10 Political considerations air pollution control, Fig. X-4, 334 pesticides, 353 Point Barrow, Alaska, 313, 315 Pollen aerobiology, Fig. X-7 air pollution, 339, 340, 343, 345-349 profiles climatic change and, 59, 60, 61, 72, 73, 74 Pollinosis, see Allergens, Airborne Pollution programs, 232 projection, Fig. X-5 worldwide, 190 Pollution, Atmospheric abatement by precipitation augmentation, 177, 178 biological, 339-349 chemical, 319, 320, 321, 327, 329-338, 357 pesticides, 354-356 effect on temperature, 194 forecasting of, 101 forests, 298 fire in, 213, 311, 312 Great Lakes area, 264, 268 hemispheric interchange of air, 188 lake eutrophication, 268 man-made influence on climatic changes, 55, 57, 65, 66, 68, 69, 71, 72, 115 urban effects, 113, 116, 117, 118, 119 models dispersion, 89, 96 weather forecasting, 93 natural causes influence on climatic changes, 55, 69, 72 volcanoes, 21, 55, 56, 68, 71, 72, 329 nuclei for precipitation, 192, 193 radioactive elements, 33 regional controls, 332 smog, 385 turbulence and, 108 acoustic monitoring, 112 upper atmosphere, 65, 69 see also Carbon monoxide Pollution, Chemical estuaries, 248 Great Lakes, 264, 265, 268 pesticides, 354-356 Pollution, Industrial atmosphere, 55, 357, 358 chemicals Great Lakes, 264 from petroleum products, 248 lake eutrophication, 268 Pollution, Noise, 326, 327 Pollution, Radioactive, 33, 323, 325 Pollution, Soil, see Soils Pollution, Thermal, 34, 199-200, 255, Fig. VIII-12, 322, 337 coastal areas, 248 fish culture and, 252 lakes, 254 Great Lakes, 263, 264, 266, 268 Lake Michigan, 257-260, Fig. VIII-13 oceans, 245 Pollution, Water abatement by precipitation augmentation, 177 antarctic, 241-242 coastal areas, Fig. VIII-7 enrichment of Great Lakes, 227, 228 forest areas, 206-207, 209, 312 lakes, 254, 257 sea farming and, 251 world ocean, 79, 82, 83, 244, 245, Fig. VIII-8 see also Pollution, Thermal; Sewage Polygons: arctic tundra, Fig. IX-15 Polygyny: population structure and, 378 Polymorphism, 373, 374 Pompano, 250 Pompeii, 40 Pond culture of fish, 217 Population density arable land in relation to, Fig. VII-8 cause of pollution, 330, 350 effect on forest and, 293 control of numbei environmental des modification of earth'-. soil fertility and, 40, 45 water use factors, 198 Porometer, 201 Porpoises, see Dolphins Port Louis, Mauritius Isl., 135 Portales, Texas, 204 Potash, see Potassium Potassium, 32, 215, 300 eutrophication in Great Lakes, 268 Power-generating plants thermal water discharges, 199-200, 249, 254, 257, 325, 337 benefits for aqua farming, 252 Great Lakes, 263, 268 influence on Lake Michigan, Fig. VIII-13 Prairies solar radiation in, 55 climatic change, 73 Precambrian rocks, 30 Precession of the earth, 54 Precipitation atmosphere-ocean system, 67, 360 biological particulates, Fig. X-6, 349 climatic records, 51, 58 dust removal by, 358 fluctuations, 57 forecasting, 100, 102 forest land, 205 in forest ecosystems, 294 indicated by tree rings, Fig. Ill— 5 models, 89, 95 modification, 169-179, Fig. VI-2 nucleation centers, 329 urbanization and, 113, 117, 118 pollution in, 119, 337 water cycle, 198, 200, Fig. VII-2 lake eutrophication, 268 world-wide, 165, Fig. VI-1 see also Rainfall; Snow Precipitation stations National Weather Service, 197 Predators balance of nature, 280 control of, 303 in forest ecosystem, 292, 302 modeling, 282 see also Isle Royale ecosystem Predictions air turbulence, 111 change in shallow-water communities, 230-231 climatic changes, 59, 61 droughts, 165-168, 172, 221 earthquakes, 35, 36, 38 forest stream temperature, 206 injury to ecological systems, 340, 342 lead concentrations in ocean, 360 long-range effects on biosphere, 280 processes in forest ecosystems, 292-293 responses of ecosystems to changes, 300 responses within ecosystems, 289 sea-air rhythms, 78, 79, 80, 81, 89 solar activities, 5, 6, 11, 13, 16-17 volcanic eruptions, 43-45 415 INDEX water supply, 197-202 weather, 94, 95, 97, 100 hurricanes, 123-124, Fig. V-3, 135, 136 severe weather, Fig. V-10 tornadoes, 137-138, 146 sec also Weather forecasting President's Science Advisory Committee (PSAC),215 Pressure atmospheric climatic records, 51, 58 cloud seeding, 129 ocean currents and, 78 sea level, model, Fig. III-6 sea temperature and, Fig. IV-5 tornadoes, 137, 144, 145 tropical regions, 188 weather, 95 effect on materials, 22, 23 subsidence, 203 Primates: malarial infection, 365 Primitive man, 74, 378 Princeton University, 87, 88 Propane, Liquified: fog-seeding nucleant, 180, 183 Protactinium-231, 53 Proteins chemical changes in, 388 in marine animals, 239, 240-242 Prudhoe Bay, Alaska, 32 PSAC, see President's Science Advisory Committee Public Health Service, U.S., 365 Puerto Rico, 135 Puget Sound, 248, 249, 250, 270, 271 Pulmonary edema (HAPE), 379, 384, 385 Pumice, 362 Punta Arenas, Chile, 241 Purdue University, 304 Purse seine, Fig. VIII— 9 Pyroclastic material, 40 Quail, 306 Quartz in dust over tropical areas, 193 in ocean sediments, 358 Quaternary volcanoes, 45, 63, 344 Quizapu (volcano), Chile, 41 Rabbits, 304, 388 "Race": human differences, 373, 374 376, 377, 378 Radar, Acoustic ultra-high resolution, 108, Fig. IV-10 WIT detection, 112 Radar, Coherent laser, see LIDAR Radar, Doppler, 95, 110, 140-141, 144, 147 Radar, Frequency modulated continuous wave, 109, 110, 111 Radar, Incoherent scatter, 9-10 Radar, Pulsed microwave cloud measurements, 170, 176 observations, 108 air-borne, 111, 129-130 ground-based, 111 hook-shaped echoes, Fig. V-7 weather modification, 178 storm detection, 94, 95 tropical areas, 187 weather prediction, 103, 104, 109, 138, 141, Fig. V-8, Fig. V-9, 147, Fig. V-10 Radiation belt, 6, 8 Radiation hazards man in space, 5, 14, 25 effects, 325 Radio waves commnications, 3, 4, 5, 8, 11, 14 lightning, 157 Radioactivity dating techniques, 53, 54, Fig. III-3, 58, 72 fallout, 332, 340 wastes, 323, 335, 357 Radiometric sounders, 87, 90, 96, 98 Radiosondes, Fig. IV-6, Fig. IV-7, 98 Radon-222, 193, 194 Ragweed pollen, 345, Fig. X-9, 347, Fig. X-10 Rainfall air-sea rhythms and, 85-86 Canton Island, Fig. IV-4 areas of malaria potential, Fig. X-19 causes, 165 cloud seeding model, Fig. VI-6 for prescribed fire in forests, 310 generation, 170 hurricane carried, 126, 128, 131, 133 in ecosystems, Fig. IX-5 tropical forests, 295, 298, Fig. IX-11 lightning and, 160 tornadoes and, 139 tropical areas, 186, 187, 189 typhoons, 140 urban-induced, 115 see also Monsoons Rajasthan Desert, India, 58 Ramage, Colin S., Fig. VI-10 RAND Corporation, The, 68 Rapid City, S. Dak., 153 Raschke, K., 202 Rawinsonde networks tornado warnings, 146 weather analysis, 101, 104 Reaction rates ocean layers, 89 precipitation mechanisms, 169 Recreation and leisure time effect on water quality, 205, 209, 210, 214 factor in environmental design, 279, 280 forest wildlife, 303 game laws and aquaculture, 251 hunting, 293, 307 noise pollution, 326 tourism in arctic, 313 water use, 200, 254, 257 see also Aesthetics Recycling of resources, 338 environmental design, 278 food chain, 226 Red crab, 240 Red scale, Fig. X-13 Redondo Beach, Cal., 203 Reducers: trophic dynamics, 225 Reflectivity of the earth, see Albedo of the earth Regional effects: urban-induced weather change, 115, 119 Regional Meteorological Center, Darwin, Australia, 185 Residence time air pollutants carbon monoxide, 358 water pollutants, 267 DDT, Fig. X-14 Great Lakes, 269 ocean-floating oil lumps, 362 oceans, 357 Resistance children to disease, 378 pest species, 350 malarial insects, 364, 365, 367 Resources, Nonrenewable: projection, Fig. X-5 Respiration air pollution and, 385, 386, 387, 388 high altitudes, 381, 385 plants, 288 Revelle, Roger (R. D.), 82 Reynolds numbers, 269 Rh babies, 374 Rhodesia, 297 Ribeirao Preto, Brazil, 369 Rice production, 218, 220 Richardson, L. F., 107, 109, 110 Richardson number (Ri), 107, 109, 111 Richter scale, Fig. II— 7 Rio de Janeiro, Brazil, 41 Rio Grande River, 31 Rio Negro River, S.A., 300 Riometers, 15 Rivers as a water supply, 187 impact on lakes, 270 nitrate concentrations in, Fig. VIII— 15 nutrient-rich, 268 thermal pollution, 34 Robbins, Robert Crowell, 330 Robinson, Elmer, 330 Robinson, George D., 68 Rockets pollution, 65, 69 used in cloud seeding, 151, 152, 153 Rocketsonde programs: weather forecasting, 101 Rocky Mountain Arsenal, Col., 39 Rocky Mountains earth processes, 28, 29, 31 precipitation, 166, 204 severe storms, 160 weather forecasting, 38 weather modification, 177 Rodents in food chain, Fig. IX-6, 302 malaria systems, 365, 366 rat middens, 73 Rosenthal, S. A., 128 Ross Sea, Antarctica, 84 Rossby, Stig A., 13, 102, 103 Rossow, V., 139 Rotation of the earth, see Coriolis force Rotifers, 228 416 Royal Observatory, Hong Kong, 185 Royal Society, London, Eng., 51 Rubber, Fig. VII-9, 297 Rubidium in isotopic studies, 30 Russia, 68, 358, 359 fishing, 232, 241, 242, 24o Moscow, 41, 53 oceans, 82, 239, 241, 244 soil, 220, 291 Ukraine, 216 volcanoes, 44 weather, 69, 100, 106 hail, 149, 151, 152, 154, 155 Rusts (plant diseases), Fig. VII-9, 339, 340, 341, Fig. X-8, 343 S-waves, 29 Saarinen, Thomas Frederick, 219 Saginaw Bay, 263 Sahara (desert), Africa, 52, 192, 193, 329 St. Lawrence River, 261, 262 St. Lawrence Seaway, 259 St. Louis, Mo., 113 St. Pierre, Martinique, 42, 44 St. Vincent (island), Lesser Antilles, 42 Salmon, 266, 271 Atlantic, 261, 262 coho, 228, 263 Salmonella, 217 Salt cloud seeding, 174, 192, 329 deposits, 28 in blood of fish, 232 in haze, 68 in irrigation waters, 291 in ocean waters, 83, 84 Salton Sea, Cal., 33 Samoa, 87 Samplers, Aeroallergen Durham, 347 impaction, Fig. X-10 rotoslide, 348 San Andreas Fault, Cal., 26, 30, 36, 37 San Bernardino Mountains, Cal., 337 San Diego, Cal., Fig. IV-10 San Francisco, Cal., 35, 38, 39, Fig. IV-12, 357 San Gabriel Mountains, Cal., 337 San Joaquin Valley, Cal., 204, 352 San Jose, Cal., 204 San Juan, Puerto Rico, 44 Sand, 135, 329 Sandstone, 203 Santa Barbara, Cal., Fig. VII-5, 361 Santa Clara Valley, Cal., 204 Sardines, 237, 238 Saskatchewan, Can., 32 Satellites APT, 185 atmospheric circulation, 90, 96 cloud cover monitoring, 68-69 drag, 14 effect of radiation, 8 instrumentation, 87, 90, 96, 98 observations from, 5, 7, 15, 22, 97, 98, 104 radiation monitoring, 58, 59, 66 sea-air studies, 78, 81, 84, 87, 100 weather forecasting, 103 tropical areas, 187, 188, Fig. VI-12, 190 Satellites, Geostationary ATS-3 atmospheric dust, 191, Fig. VI-13 hurricane surveillance, 129, 130, 134 storm tracking, 94, 95 weather forecasting, 101 Satellites, Polar orbiting ESSA-3, 124 hurricane pictures, 95, 123, Fig. V— 1, Fig. V-2 ITOS-I, 69 Nimbus-3, 90, 98 Nimbus-4, 69 Nimbus-F, 69 weather forecasting, 101 Sauger in Great Lakes, 263 Saury, 363 Savannah, Forest, 299 Scales distance, Fig. X-3 time air-sea systems, 79, 82, 83 atmospheric circulation, 91 models of the atmosphere, 90 Scandinavia, 86, 314 Schaefer, Vincent J., 154, 183 Schistosomiasis, 217, 323, 367-369 Scholander pressure chamber: soil profile, 202 Schove, D. J„ 51 Sculpin in Great Lakes, 263 Sea farming, sec Aquaculture Sea floor oil, 361-363 spreading, 22, 26-27, 29, 32 Sea lamprey in Great Lakes 262, 263, 264, 266 Sea levels, Interglacial, 54 Sea-lion, 241 Seals in sub-antarctic, 232, 240, 241, 242, 246, 247 Seas, see Oceans Seattle, Wash., 53, Fig. VI-7, 270, 271 Seaweeds as food source, 236 sub-antarctic, 232 Secchi disc, Fig. VIII-16 Sediment particles effect of land use, Fig. VII-7 flow rate, Fairfax County, Fig. VII-6 microfossils in lakes, 344 ocean floor, 358, Fig. X-17 pollen proples, 61, 72, 73 water quality and, 206, 209 Seeding techniques for fog, 188-183 see also Cloud seeding Seedlings, Hurricane: surveillance of, 123, Fig. V-l, 125, 126 Seiches, 254, 255 Seismic measuring and monitoring, 28, 31 seismographs, 22 waves, 22, 28, 29 Seismicity of the earth, 35, Fig. II— 5, 37 U.S., Fig. II-7 Selenium, 215 Sellers, William D., 67 Semi-arid regions water supply, 198 water conserving, 220 Semi-deciduous fores : Severe local storms: prediction Sewage as fertilizer, 251 effect on aquatic life, 230, 231, 233-234, 235 effect on estuaries and coastal zones, 248 effect on lakes, 254, 265 Lake Washington, 270, 271, 272, 273 in aquaculture, Fig. VIII-11 in humid tropics, 300 pollution, 230, 323, Fig. X-16 oceans, 357, Fig. X-17 Shales, 203 Shallow-water communities predictions of change, 230-231 seaweeds, 236 Sheepshead, 261, 263, 266 Shipping hazards to, 33-34, 41, 82, 180 water use to maintain stream depth, 200 weather forecasting for, 81 Ships: used for sea-air studies, 78, 79, 84, 87, 100 Shock waves solar wind, 5 seismic, 22, 35, 36, 38, 39 Shore zones lakes, 254, 255 Great Lakes, 268 see also Coastal areas Shorebirds: tundra ecosystem, Fig. IX-16 Showa Shin-Zan, Japan, 43 Shrimp sergestid, 238 Japan, 251 aquaculture, 253 see also Krill Shrimp-seals, 241 Shull, George, 218 Siberia, 189, 314 Sicily, 35 Sickle cell anemia in Liberia, Fig. XI-3 malaria and, 365, 377 race and, 373, 374 Sierra Nevada Range (U.S.), 29 Signal Hill, Cal., 203 Silicic rock, 29 Silver bromide (AgBr) : cloud seeding, Fig. VI-3 Silver iodide (Agl) cloud seeding, 128, 129, 141, 175, 192 hailstorms, 151, 152, 153, 154 lightning reduction, 161 precipitation modification, 170, 172, Fig. VI-3, Fig. VI-4 fog seeding, 180 Singapore, Fig. IV-5, 185, 238 SIRS (Satellite Infrared Spectrometer), 90, 98 Skillet Fork River, 111., Fig. VIII-15 Skin color in human populations, 374-375 417 INDEX Slash-and-burn technique in tropical agriculture, 296, Fig. XI-3 Smagorinsky, Joseph, 88 Smelt, 261, 263, 264 Smith, J. E„ 232 Smithsonian Institution, 47, 52 Smog, 12, 65, 67, 68, 113 adaptation to, 385-390 chambers, 334 photochemical, 335, 336, 385, 387, 390 ecology of, 337-338 Smokes, 65, 67, 68 air pollution, Fig. X-6 forest fires, 33 urban-induced, 113 Smut (plant diseases), 341 Fig. X-8, 343 Snails, see Schistosomiasis Snake River Plain, 29 Snow cloud seeding and, 170, 171, 177 cover climate and, 64, 68, 97 satellite monitoring, 59 tundra, 313 urban areas, 114, 117 Social implications air pollution control, Fig. X-4, 334 climatic changes, 57 man-induced weather changes, 172, 173, 175 parasitic diseases, 367, 369 pollution, 327 Social sciences: role in agricultural adaptations, 220, 221 Sodium arsenate (herbicide), 213 Soils fertility, 40, 45, 295, 296, 297 fire and microorganisms, 311, 312 in forest ecosystems, 292, 293 southern pine areas, 311, 312 tropical areas, 295, Fig. IX-10 leaching irrigation, 216 water storage and, 202 pollution, 291, 323 reserves of plant nutrients, 215 studies for ecosystems, 291 water storage, 200, 202, 211, 212 Solar constant, 52, 55 Solar flares, Fig. 1-1, 5, 6, 13, 14 Solar radiation, 3, 52, 254, 287 absorption by animals, 289 atmosphere-ocean system, 66, 67, 70 atmospheric circulation and, 89 climatic changes and, 55, 64 ecosystems, 285, 287, 288, Fig. IX-9, 301 food chain, Fig. IX-6 effect of dust, 57-58, 68, 191, 194 effect of pollution, Fig. X-2, 332 effect of snow, 89 effect of volcanic activity, 45 effect on climate, 52, 65-69, Fig. III-7 tropical areas, 186 extreme ultraviolet, 4, 9, 10 modified by CO=, 337 plant energy, 287 precipitation, 167, 173 re-radiation, 70 scattering, 58, 89 trophic dynamics, 225, 226 urban effects on, 113, 114, 116, 119 water movement and, 200, 206 Solar-terrestrial system, 3-13 Solar wind, 3, 5, 6, 8, 15 Sole, English, 249 Solfatara Volcano, Italy, 43 Solvents, Dry-cleaning: air pollution, 357 Sonar: fisheries management, 244 Sonoran Desert, Ariz., 282 Sound waves, 112 South America agriculture, 167, Fig. VII-8, 242 air-sea system, 77, 86 earth processes, 27, 28, 32, 35, 44, 59 ecosystems, 286, 291, 297, 300 environmental contamination, 364, 365, 370 human adaptation, 378 South Carolina, 309, 310 South Georgia Island, Antarctica, 239, 241 Southern hemisphere chronology of tree rings, 61 dust measurements, 194 monsoons, 184 weather forecasting, 90, Fig. IV-7, 98, 103 Soybeans, 216, 217 Space Environment Laboratory (NOAA), 16 Spain, 252 Spinel, 29 Spiny lobsters, 250 Sponges, 232 Spores: air pollution, 339, 340, 342, 343, 345 Sputum and cough, 386, 390 Squirrel, Gray, 302 Stabia (historic), 40 Stakman, E. C, 339 Standard of living, 330 Stanford Research Institute, Cal., 330 State, U.S., Department of, Fig. VI-11 Steam, Industrial: as pollutant, 329 Steering methods: weather prediction, 93, 94, 95, 148 Stokes, G. G., 192 Stokinger, H. E„ 389 Stommel, Henry Nelson, 79 Stone Age, 74 Stone-crabs, 241 Storm systems climatic records, 51 droughts and, 165 tropical, 189 influence of dust, 191-194 modification, 187 turbulence in, 108 urbanization and, 113 see also Hurricanes; Severe local storms; Tornadoes STORMFURY, Project, 126, 127-132 Strait of Magellan, 241 Stratopause, 3, 11 Stratosphere, 3, 69, 287 drift of pollutants, 190 dust in, Fig. 111-10 turbulence in, 105 Streamflows as part of water supply, 197, 198 stability of channels, Fig. VII-7 Stress measurement: earthquake prediction and, 37, 38 Strontium, in isotopic studies, 30 Sturgeon, Great Lakes, 263 Sub-Antarctica islands, 313-314 waters, 240, 241 Subsidence, in water and oil bearing formations, 203-204, Fig. VII-3 Subtropical belt of dryness, le5, 166, 167, 191 Succession principle of natural communities aquatic, 230 forests, 299, 304, 308 Suckers (fish), 261 Sukurajima (volcano), Japan, 45 Sulakvelidze, G. K., 152 Sulfur agriculture, 215 sulfur oxides air pollution, 319, 337, 360, 385, 387, 388, 390 modeling, 335, 336 natural causes, 330 smog, 337 urban areas, Fig. X-2, 319, 342 volcanoes, 21, 41, 43 sulphates contaminants, 322 increase in Great Lakes, 268 Sumatra (island), Indonesia, 41, 44 Summer anomalies, 56 droughts (U.S.), lob dust transport, 191, 192 content, 193 forest fires, 309, 310 monsoons, 184 stratification of lake water, 258 urban effects on weather, 114, 116 Sun, 3-17 climate and, 51 damage to human beings, 325 heat input on Great Lakes, 257 radiation, 4, 14, 25 sunspots, 3, 4, 13, Fig III— 1, 52, 58 see also Solar radiation Sunflowers, 216 Sunnyvale, Cal., 204 Superior Province, Great Lakes, 31 Surtsey (volcano), Iceland, 47 Sverdrup, H. U., 79 Switzerland, 154, Fig. V-14 Systematic biology, 231 Systems analysis environmental design, 289, 340 forest ecosystem, 294, 295, 300 Great Lakes water management, 267, 269- 270 maintenance of the biosphere, 281 meteorology, 339 oceans and marine productivity, 233-235 pest control, 352, 353 plants, 289 418 Taiwan, 35 Talc, 359, 360 Tall Timber Research Station, Tallahassee, Fla., 307 Tanganyika, 220 Tanzania, Fig. VII-10 Tarawa (island), 87 Taxonomic identification of plankton, 228, 230 Tay-Sachs disease, 374 Teal, John M., 3ol, 363 Teleconnections, 85, 88, 100 Telemetry animal ecology, 302 energy relations of animals in the ecosystem, 289 field studies of animals, 289 Temperate zone agricultural practices, 295 drought, 165 forests, 292, 298-301 hurricanes, 123, 124, 135 Temperature bacterial oxydation, 362 climatic records, 51, 52, cloud-seeding, 176 cloud-top, 175 CO. content of atmosphere and, 64, 67, Fig. Ill— 9, Fig. 111-10, 72, 332 deep earth processes, 22 derived from sea-core dating, Fig. Ill— 3 earth and above it, 89 historic records on, 58 human beings, 374, 376 northern hemisphere, Fig. Ill — 4, 57, Fig. III-8, Fig. III-9, Fig. 111-10 nucleating agent effectiveness, 174 sounding by satellites, Fig. IV-6 worldwide effect of dust, 194 Temperature, Atmospheric, 11, 12 distribution, Fig. 1-5 effect of CO., 119 effect on clouds, 141, 174 effect on mosquitoes, Fig. IX-3 fluctuations, tropical vs. temperate species, 298, Fig. IX-11 forecasting, 94, 100, 102 forest fires, 306, 307, 311, 312 formation of hailstones, Fig. V-ll global variations, 55 in ecosystems, 285, Fig. IX-5, 300, 301 patterns, 102 plants, 287, 288, 289 Project STORMFURY, 129 records, 51, 52 smog, 337 tropical areas, 188 urban areas, 113, 114, 116, 119 Temperature, Water Antarctica, 83, 231-232 Great Lakes, 261 lakes, 254 thermal influence, Fig. VIII-13 sea-surface, Fig. Ill— 2, Fig. IV-1 drought causes, 165 north Pacific, 78 tropical regions, 85, Fig. IV-5 water cycle, 200, 201, 202 forest areas, 206 Terrestrial ecosystems, 277-315 Tertiary era, 63, 358 Texas earth processes, Fig. II-7 ecosystems, 306, 308 groundwater, 203, 204 range management, 74 severe storms, 123, 124, 140, 147, 154 Texas Agricultural Experiment Station, 204 Texas Tech University, Lubbock, Tex., 306 Thailand, 184, 185 aquaculture, 238 Thalassemia, 373 Thera (volcano), Crete, 44 Thermal bar Great Lakes, 268, 270 lakes, 255, 258, 259 Thermal engine, 65-66, 67, 77, 123 Thermal plume in lake water, 259 Thermal pollution, see Pollution, Thermal Thermocline, 84, 87 Thermohaline alterations, 83 Thermonuclear energy, 5, 8, 25 Thermosphere, 3, 11 Thomas, Heriberto V., 388 Thomson, J. J., 10 Thorium, 30, 53 Thorpe, Steven A., 106, 109 Thunderstorms hailstorm type, 154, Fig. V-13 lightning and, 157, 160 prediction, 93, 94, 95, Fig. V-10 tornadoes and, 137, 138, 139, 144 tropical areas, 186, 187 Tibet, 184, 186 Tidal waves, 35 earthquakes and, 81 volcanic eruptions and, 44 Tides, 81, 123 atmospheric, 58 gauges, 87 sea-air system and, 78, 81 Time factor in water cycle, 202 landscape stability, 211 Tin deposits, 32 TNT, 153 Tonga, Friendly Isls., Pac. Ocean, 35 Tornadoes, 137-148 effect on water quality, 212 hurricanes and, 123 occurrence, 132 predictions, 94, 98 Torrey Canyon, S.S. (ship), 361 Toxic substances agriculture and, 278 changes in ecosystems, 280 Lake Washington, 272 see also Pollution, Chemical Toyama, T., 388 Trace elements, 34, 296 Trade winds dust from Africa, 191, 192, 193, 358 equatorial belt of wetness, 165 hurricanes and, 123 pesticides spread precipitation Transparency decrease in Great L.i! i measurements in Lai-. I Fig. VII1-16, 272 Transpiration in plants, 287 Transportation hazards due to fog, Fig. VI-8 impact of climatic change, 58, 59 Transportation, U.S. Department of, Fig. VI-11 Transverse Ranges, Cal., 29 Tree rings: climatic change shown by, 58, 59-61, Fig. III-S Trees, see Forests; Vegetation Triggering agents climatic events, 55, 69 convection, 119 earthquakes, 37, 39 gravity waves and turbulence, 106 precipitation, lead-contaminated, 118 waves, 111 waves and wind speed, 110 Trophic dynamics aquaculture and, 252 estuaries, 248-253 Great Lakes, 225-229, 230, 261 world ocean, 236-247 Trophic levels aquatic, Fig. VIII— 1, 226, 227, 228 estuaries, 248 Tropic of Cancer: atmospheric dust, 191 Tropical medicine, 364-370 Tropical regions air-sea rhythms, 84-88 animal diseases, 217 atmospheric composition, 330 climatic changes, 57, 133 drought, 220 effects of dust, 191-194 human adaptation in, 378-379 natural air contaminants, 330, 344 radiative balance, 68 soil studies, 291, 295-297 storms see Hurricanes; Typhoons weather forecasting, 90, 91, 95, 98, 184-190 Tropopause, 105 Troposphere, 3, 11, 69 atmospheric circulation studies in, 90, 105 drift of pollutants, 190, 357 dust in, Fig. Ill 10, 193 tropical weather, 186 Trout freshwater, 225, 251, 261, 262, 263, 266, 271 sea, 253 Trout, Dennis, 105 Trypanosomiasis, American, see Chagas' disease Tsetse fly, 344 Tsunamis, see Tidal waves Tundra biomes, Fig. IX-15, 314, 315 Tungsten, 31, 90 Turbidity atmosphere, 339 419 INDEX measurement, 1°4, 331 monitoring, 56, 58 role of aerosols, 68, 71 urban-induced weather change, 119 forested watersheds, 206, 209, 210 Turbulence earth's magnetic field, 6 forest canopy, 201 in atmosphere, 91, 335 urban-induced, 113 wave-induced, 105-112 in mesosphere, 12 lake waters, 254, 256, 260 tornadoes, 138 Turkey (country), 35 Turkey, Wild, 302, 306 Turner, J. S., 140 Typhoons study of effects, 185 weather forecasting, 102 models, 91 u Uccle, Belgium, 68 Udall, Kans., 139 Ukraine, 21o Ultraviolet radiation, 55, 287 ionosphere, °, 11 urban areas, lip United Nations: environmental research, 344 United States agriculture, 199, 215, 218, 219, 291, Fig. X-8 air-sea interaction, 56, 7}, 81, 89, 97, 106, 109 climatic change, 57, 08, 73, 74, 220 data networks, Fig. IV-7, 141, 147 drought, lo5, loc, 219 earth processes, 28, 29, 32, 45, 48 ecosystems, 205, 232, 233, 241, 24c, 251- 253, 261, 293, 295, 300, 302, 30t>, 308 environmental contamination, 69, 192, 194, 329-332, 334, 343, 345, Fig. X-9, Fig. X-12, 367, 369, 390 human adaptation, 373, 374, 378, 379, Fig. XI-6 pollution, 265-268, 270 regional weather, 185, 188 severe storms, 123, 126-128, 130, 133, 135, 137-139, 146, 149, 151, 153-155, 157, 158 urbanization, 113, 114, 118, 119, 283 volcanoes, Fig. II— 8 water resources, 210, 361 weather forecasting, 35-40, 42, 44, 94, 100, 103, 104, 181 weather modification, 170, 172, 181-183 Updrafts, 149, 150 Upper Colorado Pilot Project, 172 Upwelling coastal, 80, 86 lake water, 255, Fig. VIII-12, 259, 269 Uranium, 30, 32, 325 Urban areas aircraft pollution, 65 atmospheric chemistry, 336 biological pollution, 342, 343 ecology of smog, 337 hurricane damage, 135 ice nuclei, Fig. VI-7 solar radiation in, 55 Urbanization air pollution-smog, 385 effects on large lakes, 22o effects on water supply, 198 effects on weather, 114, 115, 118 environmental design requirements, 278 humid tropics, effect on ecology, 300 sea farming and, 251 spread of parasitic disease, 369 water quality and, 261 weather changes and, 113-120, Fig. IV-11 Urea cloud-seeding nucleant, 174 fog-seeding nucleant, 180 Ury, Hans K„ 388 USGS, see Geological Survey, U.S. Utah groundwater, 204 seismic refraction profile, 29, 31 Valley of Ten Thousand Smokes, Alaska, 42, 44 Vegetation affected by smog, 337 carbon dioxide removed from air, 358 effect on aeroallergens, 349 effect on water movement, 200, 201, 202 effect on water quality, 212, 265 fire and, 306 forested areas, 302 fossil studies, 73 pollen profiles and, 61 restoration upon lava flows, 41 sulfur dioxide removal from air, 330 urban areas, 118 western America, 74 see also Plants VELA program, 23 Venezuela, 33, 203 environmental disease, 369 genetic differences, 374, Fig. XI-1, Fig. XI-2 Ventilation: water movement and storage, 200, 202 Ventura-Winnemucca earthquake zone (Cal. and Nev.), 31 Verification systems: weather forecasts, 102, 103 Veronis, George, 82 Vesuvius (volcano), Italy, 40, 43, 45 Vigo, Bay of, Spain, 251 Virginia effects of hurricanes, 133 Fairfax County, Fig. VII-6 urban-induced weather change, 118 Viruses, Fig. X-6, 341, Fig. X-8 Visibility: urbanization and, 113, 117 Vital statistics: high altitude populations, 385 Volcanoes, 21, 40-48 carbon gases, 43 effects on water quality, 212 forest soil, 295 records on, 58 sea floor topography, 27-28 sec also, Ash, Volcanic Von Neumann, John, 97 Vonnegut, B., 139, 183 w Waite, P. J., 139 Walker's "southern oscillation", Fig. IV-5 Waller, H. J., 388 Walleye, 261, 263 Wallihan, Ellis F., 201 Wallops Island, Va., 10<> Walter Reed Army Institute for Research, 3c5 Ward, N. B., 140 Warm fog, 181, 183 Warning systems ecological changes, 344 ecological damage, 340 hurricanes, 136 tornadoes, 138, 144, 148 Wasatch Range, U.S., 31 Washington crustal velocity, 29 fishery technology, 252 urban-related precipitation, 113, 119 volcanoes, 31, 40, 44 weather modification, 101 see also Seattle Washington, D. C, 68, 98, 185 Washington, University of, 330 Forest Service, 306 Waste management conservation and, 338 detinition of wastes, 330 forestry and, 213, 301 human ecosystem, 278 land pollution, 248, 323 rivers and, Fig. X-2 Water contamination, 329 hurricane clouds, 129 volcanic action and, 42, 43 Water budget cloud systems, 171 Great Lakes, 269 Lake Washington, 273 precipitation augmentation, 177 urban areas, llo Water conservation devices, 296 Water management development schemes and parasitic diseases, 369 Great Lakes, 266, 267 Water quality arid regions, 291 diverted use, 198 environmental design and, 278 forest areas, 205-214 Great Lakes, 2ol-270 lakes, 226, 227, 230, 257 standards, 214 Water resources, 197-204 Water shortages, 178 priorities, Great Lakes, 270 Water supply agriculture, 215-216 420 contaminants, 322 data bases, 197 desert areas, Fig. IX-3, 291 for tundra vegetation, 313, Fig. IX-16 forest land, 205, 292, 300, 307 tropics, Fig. IX-10 storage in rocks, 203 tropical areas, 187, 188 Water use, 198, l°o-200 Water vapor as pollutant, 337 disease carrier, Fig. X-21 atmosphere-ocean system, 66, t>7, 71 hail clouds, 152 heat balance of the earth and, 287, 288 hurricanes, 131 in clouds, 331, 337 in pure air, 329 precipitation, Fig. VI-2 storm forecasting, 138 tornado models, 139 urban area weather, 119 Watersheds forest areas, 20e, 209, 211, 212 lakes, 273 northern hardwood, 293-295 Waterspouts, 144, 147 Waves data, 78, 80 hurricanes, 127, 128 induced turbulence, 108-112, Fig. IV-10 kinds gravity, 106, 111 Kelvin-Helmholtz, 109, 110, 111 Kelvin type, 255 lakes, 254, 255, 256, 259 models, 81 ocean-surface, Fig. IV-2 Weasels in food chain, Fig. IX-6 tundra ecosystem, Fig. IX-16 Weather, 62 prescribed tire and, 311 urban-induced change, 119 see also Radar Weather forecasting, Fig. IV-9 anomalies, 87, 88 climatology, 103 data base, 90-92, 93, Fig. IV-7, Fig. IV-8, 98, 103 extrapolation method, 93, 94, 95, 97 for fishing industry, Fig. VIII— 7 models, 93, 94, 95, 96, 97, 102 extended periods, 99, 105 role of oceanography, 82, 100 short-range, 94-96, 101-104 tropical areas, 184, 189 storms and hurricanes, 187 urban-induced changes, 114, 115 Weather modification at airfields, 101 environmental management, 283 hail, 151 hurricanes, 126 lightning, 158, 190-161 tornado windspeed, 145, 146 urban-induced, 113-120, Fig. IV-11 see also Climate: control; Precipitation: modification Weather stations, 137, 138, 146 Weatherald, Richard T., 67, t>9 Weddell Sea, Antarctica, 84, 232 Weddell Seal, 232 Wegener, Alfred E., Fig. II-4 Well drilling, 203 Welland Canal, 261, 2c2 Weller, N., 139 Wells, Philip V., 73 West Germany, 181 West Indies, Lesser Antilles, 42, 134 West Virginia, 133 Western hemisphere dust from Africa and, 191 model of sea-level pressure, Fig. III-6 Whales, 232, 241 in food chain, Fig. VIII-6 management of stocks, 245-24o source of food, 240, 242 Wheat, 216, 217, 220, 289 White Mountains, Cal., el White Mountains, N.H., 293 Whitefish food fish, 227 Great Lakes, 261, 262, 263, 264 Lake Washington, 271 WHITETOP, Project, 170, 171, 172 WHO, see World Health Organization Wilderness reserves see Isle Royale ecosystem Williams, Roger J., 376 Wilmington, Cal., 203 Wind distribution in tornado vortices, 138 tornado models, 139 flow patterns atmospheric pollutants and, 335, 336, 344, 360 climatic change and, 56, 100 drought, 165 fog dispersal operations, 180 forecasting, 102, 104 hailstorms, 149 models, 89, 95 monsoons, 184 sea-surfaces and, 78, 86 severe storms, 125, 129, 130, 135, 138 tropical areas, 188 urbanization and, 113, 114, 116 water circulation, 254, Fig. VIII-12 weather modification systems, 174 shear, turbulence and, 108 speed atmospheric pollution, 347, Fig. X-10 climatic records, 51 cloud seeding, 176 factor in plant growl: :. forest fires, 306, 310 hailstorms, 149, 150, Fig. V-13 hurricanes, 123, 127-128 tornadoes, 137, 144-145, 14o tunnels air pollution research, 334 hail, 150 Wind River Basin, Wyo., 31 Winter dust transport, 191, 192, 193 forest fires, 310 monsoon winds, 184 temperatures, 56, 57, 114 Wisconsin, 257, 2o3, 269 Wisconsin, University of, 269 WIT (wave induced turbulence), 108, 109, 110, 111, 112 WMO, sec World Meteorological Organization Wolf, Timber, 302, 304-305 Woods, J. D., 106, 109 Woods Hole Oceanographic Institution, Mass., 3e>l Work capacity, at high altitudes, Fig. XI-4, Fig XI-5, 382 World Data Centers (Wash., D. C; Moscow, U.S.S.R., etc.) : space data clearinghouse, 15 World Health Organization (WHO), 379, 380, 385, 388 World Meteorological Organization (WMO), 91, 100, 185, 188, 340 see also Commission for Climatology World Weather Program (WWP), 91 World Weather Watch (WWW), 59, 91, Fig. IV-7, 100, 101, 190 Wright, Sewall, 374 WWP, see World Weather Program WWW, sec World Weather Watch Wyoming, 29, 31 XBT, see Expendable Bathy-Thermographs X-rays, 4, 9, 10, 11, 15 effects on humans, 325 fluctuations, 55 Yanomama Indians, Brazil, 374, Fig. XI-1, Fig. XI-2, 378, 379 Young's modulus, 203 Young, Thomas, 203 Zinc, 193 Zooplankton, Fig. VIII— 5 in food chain, 234, 237, 240 in lakes, 227, 228, Fig. VIII-2, 262 421 CONTRIBUTORS The following list is composed of (1) the names of people who responded in writing to a request for information in an area of their special interest and (2) the names of those people who contributed illustrative material for use in the report. In some cases, individuals contributed both text material and illustrations. WILLIAM C. ACKERMANN, Illinois State Water Survey CLIFFORD AHLGREN, Quetico-Superior Wilderness Research Station DURWARD L. ALLEN, Purdue University DAYTON L. ALVERSON, National Oceanic and Atmospheric Administration DAVID ATLAS, National Center for Atmospheric Research PAUL T. BAKER, The Pennsylvania State University ROGER G. BARRY, University of Colorado PAUL C. BEAVER, Tulane Medical Center W. BOYNTON BECKWITH, United Air Lines WILLIAM S. BENNINGHOFF, University of Michigan JACOB BJERKNES, University of California at Los Angeles F. HERBERT BORMANN, Yale University DUNCAN C. BLANCHARD, State University of New York at Albany ROSCOE R. BRAHAM, JR., The University of Chicago WALLACE S. BROECKER, Lamont-Doherty Geological Observatory JOHN L. BROOKS, National Science Foundation LINCOLN P. BROWER, Amherst College KIRK BRYAN, National Oceanic and Atmospheric Administration REID A. BRYSON, The University of Wisconsin at Madison SIR EDWARD C. BULLARD, University of Cambridge T. C. BYERLY, U.S. Department of Agriculture TOBY N. CARLSON, National Oceanic and Atmospheric Administration DAVID C. CHANDLER, University of Michigan STANLEY A. CHANGNON, JR., Illinois State Water Survey GABRIEL CSANADY, University of Waterloo ALLAN C. DeLACY, University of Washington ROBERT E. DILS, Colorado State University HANS DOLEZALEK, Office of Naval Research WILBUR G. DOWNS, The Rockefeller Foundation RICHARD C. DUGDALE, University of Washington JOHN A. DUTTON, The Pennsylvania State University W. THOMAS EDMONDSON, University of Washington KENNETH O. EMERY, Woods Hole Oceanographic Institution CESARE EMILIANI, University of Miami ROBERT D. FLETCHER, Department of the Air Force (Retired) THEODORE T. FUJITA, The University of Chicago NORIHIKO FUKUTA, University of Denver DONALD FUQUAY, Forest Service, Missoula DAVID M. GATES, University of Michigan R. CECIL GENTRY, National Oceanic and Atmospheric Administration STANLEY P. GESSEL, University of Washington JAMES GILLULY, Geological Survey (Retired) RAYMOND M. GILMORE, Natural History Museum at San Diego EDWARD D. GOLDBERG, Scripps Institution of Oceanography JOHN R. GOLDSMITH, Department of Public Health, State of California FRANK B. GOLLEY, University of Georgia DAVID R. GOODALL, Utah State University ARNOLD L. GORDON, Lamont-Doherty Geological Observatory LEWIS O. GRANT, Colorado State University WILLIAM E. GORDON, Rice University ROBERT F. GROVER, University of Colorado Medical Center JOEL W. HEDGPETH, Oregon State University at Newport CHARLES L. HOSLER, The Pennsylvania State University HENRY G. HOUGHTON, Massachusetts Institute of Technology (Retired) CARL B. HUFFAKER, University of California at Berkeley ROBERT R. HUMPHREY, The University of Arizon PATRICK M. HURLEY, Massachusetts Institute c Technology EDWIN 5. IVERSON, University of Miami CLA'i TON E. JENSEN, National Oceanic and Atmospheric Administration PHILIP L. JOHNSON, National Science Foundation RALPH G. JOHNSON, The University of Chicago ARCHIE M. KAHAN, Bureau of Reclamation HIROSHI KASAHARA, Food and Agriculture Organization ROBERT W. KATES, Clark University WILLIAM W. KELLOGG, National Center for Atmospheric Research GEORGE C. KENNEDY, University of California at Los Angeles EDWIN KESSLER, National Oceanic and Atmospheric Administration J. E. KIRBY, JR., Esso Eastern, Inc. JOHN A. KNAUSS, University of Rhode Island LEON KNOPOFF, University of California at Los Angeles EDWIN V. KOMAREK, Tall Timbers Research Station HELMUT E. LANDSBERG, University of Maryland NOEL E. LaSEUR, The Florida State University EDWARD R. LEMON, Agricultural Research Service and Cornell University HELMUT H. LE1TH, The University of North Carolina at Chapel Hill GENE E. LIKENS, Cornell University RAY K. LINSLEY, Stanford University C. GORDON LITTLE, National Oceanic and Atmospheric Administration FRANK B. LIVINGSTONE, The University of Michigan JAMES P. LODGE, National Center for Atmospheric Research EDWARD N. LORENZ, Massachusetts Institute of Technology JOHN LYMAN, The University of North Carolina at Chapel Hill GORDON A. MACDONALD, University of Hawaii BASSETT MAGUIRE, JR., The University of Texas at Austin PAUL S. MARTIN, The University of Arizona THOMAS R. McGETCHIN, Massachusetts Institute of Technology CARL E. McTLWAIN, University of California at San Diego WILLIAM G. MELSON, Smithsonian Institution HENRY W. MENARD, Scripps Institution of Oceanography RICHARD S. MILLER, Yale University J. MURRAY MITCHELL, JR., National Oceanic and Atmospheric Administration CLIFFORD H. MORTIMER, The University of Wisconsin at Milwaukee WALTER H. MUNK, University of California at San Diego GARTH I. MURPHY, University of Hawaii IEROME NAMIAS, Scripps Institution of Oceanography JAMES V. NEEL, The University of Michigan MORRIS NEIBURGER, University of California at Los Angeles JACK E. OLIVER, Cornell University LOUIS J. OLIVIER, World Health Organization HARRY ORVILLE, South Dakota School of Mines and Technology RICHARD E. ORVILLE, State University of New York at Albany LOUIS C. PAKISER, JR., Geological Survey EUGENE N. PARKER, The University of Chicago WILLIAM G. PEARCY, Oregon State University ALLEN D. PEARSON, National Oceanic and Atmospheric Administration SVERRE PETTERSSEN, London, England GEORGE W. PLATZMAN, The University of Chicago JOSEPH F. POLAND, Geological Survey ROBIN D. POWELL, Veterans Administration JOSEPH M. PROSPERO, University of Miami COLIN S. RAMAGE, University of Hawaii GILBERT S. RAYNOR, Brookhaven National Laboratory RICHARD J. REED, University of Washington GEORGE C. REID, National Oceanic and Atmospheric Administration JOSEPH L. REID, Scripps Institution of Oceanography ELMAR R. REITER, Colorado State University HERBERT RIEHL, Colorado State University WALTER O. ROBERTS, University Corporation for Atmospheric Research GEORGE D. ROBINSON, The Center for the Environment and Man, Inc. EMANUEL D. RUDOLF, The Ohio State University RICHARD J. RUSSELL, Louisiana State University (Deceased) JOHN R. RYTHER, Woods Hole Oceanographic Institution ELVIO H. SADUN, Walter Reed Army Medical Center LYLE S. ST. AMANT, Louisiana Wild Life and Fisheries Commission FREDERICK SANDERS, Massachusetts Institute of Technology 424 FREDERICK SARGENT II, University of Texas at Houston RICHARD A. 5CHLEUSENER, South Dakota School of Mines and Technology THEODORE W. SCHULTZ, The University of Chicago J. ALLEN SCOTT, National Institutes of Health (Retired) FRANCIS P. SHEPARD, Scripps Institution of Oceanography (Retired) JOANNE SIMPSON, National Oceanic and Atmospheric Administration ROBERT H. SIMPSON, National Oceanic and Atmospheric Administration JOSEPH SMAGORINSKY, National Oceanic and Atmospheric Administration TERAH L. SMILEY, The University of Arizona RAY F. SMITH, University of California at Berkeley STANFORD H. SMITH, National Oceanic and Atmospheric Administration FOREST W. STEARNS, The University of Wisconsin at Milwaukee ARTHUR C. STERN, The University of North Carolina at Chapel Hill HENRY M. STOMMEL, Massachusetts Institute of Technology EARL L. STONE, Cornell University JOHN D. H. STRICKLAND, University of California at San Diego (Deceased) WILTON STURGES, III, University of Rhode Islan JOHN C. F. TEDROW, Rutgers University MARTIN A. UMAN, University of Florida at Gainesville GEORGE VAN DYNE, Colorado State University JOHN VERHOOGEN, University of California at Berkeley BERNARD VONNEGUT, State University of New York at Albany FRANK H. WADSWORTH, Institute of Tropical Forestry PAUL E. WAGGONER, The Connecticut Agricultural Experiment Station JOHN M. WALLACE, University of Washington HELMUT K. WEICKMANN, National Oceanic and Atmospheric Administration JOHN M. WEIR, The Rockefeller Foundation KARL F. WENGER, Forest Service FRANS E. WICKMAN, The Pennsylvania State University FORD WILKE, National Oceanic and Atmospheric Administration (Retired) HAROLD G. WILM, University of Vermont HATTEN S. YODER, JR., Carnegie Institution of Washington PAUL C. YUEN, University of Hawaii CONSULTANTS LOUIS J. BATTAN, The University of Arizona JOHN E. CANTLON, Michigan State University WILBERT M. CHAPMAN, Ralston Purina Company (Deceased) JULIAN R. GOLDSMITH, The University of Chicago ROGER REVELLE, Harvard University GILBERT F. WHITE, University of Colorado STAFF DIRECTORS EUGENE W. BIERLY, National Science Foundation LAWTON M. HARTMAN, National Science Foundation 425 NATIONAL SCIENCE BOARD (AS OF MAY 1, 1972') Chairman DR. H. E. CARTER, Coordinator of Interdisciplinary Programs, University of Arizona Vice Chairman DR. ROGER W. HEYNS, President, American Council on Education, Washington, D. C. DR. R. H. BING, Visiting Professor of Mathe- matics, Department of Mathematics, Uni- versity of Texas at Austin DR. HARVEY BROOKS, Gordon McKay Pro- fessor of Applied Physics and Dean of En- gineering and Applied Physics, Harvard University DR. ROBERT A. CHARPIE, President, Cabot Corporation, Boston, Massachusetts DR. LLOYD M. COOKE, Director of Urban Affairs, Union Carbide Corporation, New York, New York DR. ROBERT H. DICKE, Cyrus Fogg Brackett Professor of Physics, Department of Phys- ics, Princeton University DR. WILLIAM A. FOWLER, Institute Profes- sor of Physics, California Institute of Tech- nology DR. DAVID M. GATES, Professor of Botany and Director, Biological Station, Depart- ment of Botany, University of Michigan DR. NORMAN HACKERMAN, President, William Marsh Rice University DR. PHILIP HANDLER, President, National Academy of Sciences DR. CHARLES F. JONES, Vice Chairman of the Board, Humble Oil & Refining Com- pany, Houston, Texas DR. THOMAS F. JONES, JR., President, Uni- versity of South Carolina DR. JAMES G. MARCH, David Jacks Profes- sor of Higher Education, Political Science, and Sociology, School of Education, Stan- ford University DR. ROBERT S. MORISON, Professor of Sci- ence and Society, Program on Science, Technology, and Society, Cornell Uni- versity DR. GROVER E. MURRAY, President, Texas Tech University DR. E. R. PIORE, Member, Board of Directors, International Business Machines Corpora- tion, Armonk, New York DR. FRANK PRESS, Chairman, Department of Earth and Planetary Sciences, Massachu- setts Institute of Technology DR. JOSEPH M. REYNOLDS, Boyd Professor of Physics and Vice President for Instruc- tion and Research, Louisiana State Uni- versity DR. FREDERICK E. SMITH, Professor of Ad- vanced Environmental Studies in Resources and Ecology, Graduate School of Design. Harvard University DR. ATHELSTAN F. SPILHAUS, Fellow, Woodrow Wilson International Center for Scholars, Smithsonian Institution DR. H. GUYFORD STEVER, Director, National Science Foundation MR. RICHARD H. SULLIVAN, Assistant to the President, Carnegie Corporation of New York, New York, New York DR. F. P. THIEME, President, University of Colorado Executive Secretary MISS VERNICE ANDERSON, National Science Foundation ' Includes one vacancy. 426 i ant r\ _ ^nfl. Oo-*