4 Aled. Kiedfield NFERENCE MARCH '5B \ ae } = CLE is a o see. V4 SE yt j ~/) [MARINE INSTITUTE ~~ THE UNIVERSITY OF GEORGIA M/18lN MT LLL PROCEEDINGS Salt Marsh Conference held at THE MARINE INSTITUTE of the UNIVERSITY OF GEORGIA SAPELO ISLAND, GEORGIA March 25-28, 1958 Published by the Marine Institute of the University of Georgia with aid from a grant from the National Science Foundation. Athens, Georgia April, 1959 cover by University of Georgia Art Department. Printed by The University of Georgia Printing Department, Athens, Ga. April, 1959 ‘uosuyof Youepary “gp forworyD uyof “Lp teunsy[@A “YU ‘f 9p fxayeys WPYTEAN “Sh SSHEAN Pong “pp SAoTPeIG “H “AN “eh feuded “f WEITJIA ‘Gh ‘UeBIOW, “q sowmef Tp :youRqing WITT “OP Suosilapuy “AV WEITTIA “6 ‘4BNHOA “I ‘Lf “8E fjasnidg aB10245 “2g S19] Ape “9e ‘umpo “L “H “Se ‘sMezpuy Aef “pe ‘sx9a1g “y “f ‘ee ‘AU “A WPH "ZE e[PM Weqiey TE fu1o0ysieg “S$ OS[y “OE ‘1e[Zueny preMpy 6% snumig "JT uAjaaq “8% ‘MOW “L UMP “16 frauseA, YuUey 9% taaygow Aepreg “y "sz *yoKq ueA [Yq HZ ‘pAog “H e8109g “ez *ABY “A IOIIA “ZZ {PUB[PULAY GOUeIMET “TZ ‘][assny “f preyorY “OZ *SeAeH preuoy “q “6 ‘uosuaraig “q Meqoy “gl ‘aryzosey “y Weqoy “LT Suuemyonyog “YA OT sAaqTeuUg “Gy pay “GT ‘uleprequey) “T ‘f ‘PL {PPYPEM ‘DO PAHV “EL *1S19Z UYoL “ZI *[e4yoszueH IOIEA “TL ‘KolwwWog “Yo suUIIMeT “OL ‘PAL “We UYyof “6 ‘4euUaf “| seTtey °g txaurayuaddg prey “2 ‘urqny Jodo “9 SF[OPUY “Y “UH “S sJeplouyng [ned “p fesuypPyW O “aA “"g ‘ueudeyy “f “A “Z ‘dney W Yny T SLNVGNAILLV JDNIYIINOD ke ST VIDWOND 40 ALISNEAINA © ae oS Ra RIS ie 2 AAD ALAS NL ANY W 4 ‘ A = : Se se - ; ~ fa me ee iil EDITORIAL COMMENT AND ACKNOWLEDGEMENTS Abstracts of the papers appear as furnished by the authors. Because ot the freshness and unrestrained charac - ter of the discussion, it was important that it be retained in as nearits original formas possible. Therefore a minimum number of changes were made by the editorial committee. Technical changes, where they were necessary, were made by the discussants themselves. We have enjoyed wholehearted cooperation by the authors in submitting their abstracts and by the discussants in making technical corrections in their comments. For this we wish to express our appreciation. The assistance of Alfred E. Smalley in transcribing the tape recording is also gratefully acknowledged. Finally we are grateful to Mrs. Lois G. Scott for her painstaking work in typing the final copy. The editorial task was shared by the entire commit- tee, but final responsibility for any errors rests with the chairman, Robert A. Ragotzkie, Chairman Lawrence R. Pomeroy John M. Teal Donald C. Scott iv TABLE OF CONTENTS Frontispiece, Photograph of Participants Editorial Comments and Acknowledgments , 2 list of Figures , ee ee Fora ec ee cee List of Attendants and Contributors . . . . . . . Introduction , . ‘ ‘ z ‘ ‘ Part I. Salt Marshes as Land Forms. The Physiography of Salt Marshes. Jem SLC ERS a oe mei. San Fes Ee Origin of Dutch Tidal Flat Formations. Its IME dig Wo WE SEEING 45 5 GCC Drainage Patterns in Salt Marshes. Ris ING IREOWASI GO 6 90 oO ©0 56 Alluvial Morphology of Louisiana Salt Marshes. R. J. Russell Ae Ee Oe Sp iv cdly W Sone Besly ans Coastal Morphological Changes Resulting from Hurricane "Audrey", J. P. Morgan So OL. Ue Soup ate ae pkeaee The Barnstable Marsh. A. G. Redfield aA tee a So ee eee ee: The Sedimentary Environment of Newport Bay. R. WE Stevenson Maks Ce eeek 6.8 Jane. ee Comments on the Geologic History of the Sea Islands of the Southeastern United States. Je Mz Zeigler Ah a Sy Ok Pre Ge © (One +O Part Il. Salt Marshes as Vegetation. Relationships of Salt Marsh Vegetation. V. J. Chapman iv 22 29 32 37 ZS 45 47 Ecological Observations of Pools in the Salt Marshes of New Jersey. Be ie aMoulys) 5) Sean ge st) soe) et Siete ae ee Nutritional Factors in Salinity and Temperature Tolerance of Some Phytoflagellates. 5S. Secheriand bh 2. Moul seyret vce base Pen eo ee ee Some Microbiological Aspects of Marine Productivity in Shallow Waters. BP Rabarkholder” <5 2 yen Sct eel” cores) 3. ee et Part III. The Salt Marsh as an Ecosystem. Circulation of Heat, Salt, and Water in Salt Marsh Soil. A.gG. Redfield —. cs) Aw aa W pop hele eos) Oe ere ee cr slat Algal Productivity in Salt Marshes. ly kts IPhooneetehe gq 5 oo oo OG UU em The Growth Cycle of Spartina and its Relations to the Insect Populations in the Marsh. A Ge Smalley <4. 25705 Oe We ees we. ae es! “OG Energy Flow in the Salt Marsh Ecosystem, Tes SLeala eat © cen GCb cette Biestetrto ey © Owe mere) 0) Part IV. Salt Marshes as Historical Records. Paleobotanical Studies in Salt Marsh Deposits with Special Reference to Recent Changes in Sea Level. E. S. Barghoorn Sos, We Ay Vcore te eee EEE tome yer LOO Some Aspects of the Biochemistry of Mud. J. R. Vallentyne oo, WOU nce Peg oe Gia ol Moeeede 26 LULA! Archaeology and Salt Marsh Problems in the Taunton River Valley, Massachusetts. Helin. sap: Ged ko Site ee ae” 20..o eei Archaeology and Salt Marsh Problems in Massachusetts Es Johison o3) ao. JG eae ee 4 Oe eee se ae Elements of Actuo-paleontology. WieiSchater cc. te) oe se bet ghepeee ot oe tor ike) ney e oc ema Trails and Burrows on the Tidal Flats of the North Sea and Their Paleontological Significance. Wi. Hantzschel v0 .- os) ko soe. Se ee ee ee Wye 14, Wye Wee FIGURES. Diaprampon Wadden seasenviTonnmie nts sla) lenin cmc ts ue) Lia Contact of two series of deposits formed in tidal flat Enyvigonme nts, jsifpcs = and—sciliates—smicrofauna—macrofauna. detritus In view of the need for B vitamins by certain green flagellates, diatoms and photosynthetic marine bacteria, it is important to learn more about the distribution of these compounds in the sea. Studies on vitamin B]2 in muds and suspended matter of the Sapelo region have been published (Burkholder wl and Burkholder, Limnology and Oceanography, 1, 202, 1956; Starr, Ecology, 37) 658) 11956). More recent studies on B vitamins in Bahia Fosforescente, Puerto Rico, show values as follows in my/gm. of dried mud: Bj, 280; biotin, 7; and Bj, 73, or a ratio of about 40:1:10. Calculated ratios for half maximum growth of vitamin-requiring microorganisms would be about 1:1:800, expressed in weight of B)>: biotin: B]. Vitamin B)2 appears to be present in relative ex- cess, while thiamine may be a limiting factor for growth of some benthic pop- ulations. Data obtained for ten segments of a mud core taken from the Bahia suggest that these B vitamins may decrease steadily with increasing depth and age of the sediments. Of the total B)> activity in muds, assayed with a mutant strain of E. coli, from 7 to 29 percent appeared to be cyanocobalamine, as in- dicated by Ochromonas determinations. The ratio of B;> in suspended solids to Bj2 in solution was found to be about 2.5 in the waters of Bahia Fosforescente. Assays showed that B)>3 is contributed from land drainage and also is produced in shallow marine waters at significant physiological levels. The ecological relationships among organisms is oftentimes regulated by chemical factors. One of the new aspects of this general problem is the role of antibiotics in nature (Brian, Symposium on Microbial Ecology, Soc. Gen. Microbiol., Cambridge U. Press, 1957). Our recent studies on antibiotic substances in marine organisms have revealed interesting antimicrobial prop- erties of gorgonian corals collected from reefs located off the southern coast of Puerto Rico. Sea whips, sea fans and plexaurid corals were inhibitory to many bacteria. The sea whip, Antillogorgia turgida, was especially striking in its action against numerous marine bacteria, Micrococcus aureus, Clostrid- ium feseri, and others, The active principle appears not to be located in the brown core of horny corals, but is present in the outer cortex. Little or no antimicrobial activity could be detected in species of stony corals that were tested. These data suggest that antibiotics may have importance, and deserve further consideration, in marine ecology. DISCUSSION Davis: I would like to make a few comments about soft coral and Thalassia and ask the speaker some questions about it. The Florida coast has shallow waters and probably amounts to 500 miles of coral reef tract. There is 187 miles above Tortugas. I would imagine that you might have to modify some of that be- cause the Thalassia colonies are fewer down in your part of the country but as you progress northward you get Cymodocea and other things. I would question making that a separate type although from a plant ecological point of view that may be safer. Burkholder: Have you ever seen them down there in the islands ? Davis: Yes. I have been on Andros too. Thalassia covers the whole (2 business. I have seen it in Jamaica and other places. I think between the temperate Spartina and the tropical Thalassia, you would have to incorporate the manatee grass. The manatee grass (Cymodocea) is very abundant, If you have been along the Florida beaches, you can see that at certain times of the year that is much more important than Thalassia. You go out in about 6 feet of water and get to about 20 feet of water and you have still got a mixture of the two. So if you want to describe these marshes you might include those and then you have two or three other species. Burkholder: Yes, that is right. Davis: So you end up with a submarine, or if you wish to call it benthic marsh, or submarine type vegetation which begins with Thalassia and changes gradually to Spartina as you go north, but I think your word ''marsh'! is entirely correct. When you get to marsh man- groves I go with Dr. Chapman on that; you must buy the propo- sition that mangrove peat itself can form without Thalassia. It can do it right on top of other mangrove peat. Thalassia will seek soft mud. Cymodocea will seek hard sand. There is quite a bit of difference in the bottom elements, but you can re- place them all with mangrove. Oppenheimer: I would like to make a few comments on Dr. Burkholder's work with Thalassia because I have been working in Thalassia beds too in our shallow bays down in Texas. It is rather unique in that we have a rather strong onshore wind most of the year and our Thalassia beds grow in a sort of mucky material which is a fine silt with diatoms, algae and bacteria, but during the times that the wind blows these sediments all go up into suspension. We have been able to find differences in Thalassia beds which we think may be due either to chemical precipitation by some- thing put out by the Thalassia beds or due to the filter action of certain organisms, mainly shelled organisms which are in the beds. So, therefore, in one bed the water will remain cloudy for a good long period of time, the material settling out from the water onto the Thalassia leaves. The material builds up on the leaves. Then it sloughs off and falls down onto the bottom, but in the other beds the water becomes clear within a very short time after the storm and we think that this is due to one of these two processes (we don't know whicn one). We think that it is filter feeding organisms that are picking all the bac- teria, the diatoms, the algae, and the silt with other organic material adsorbed on it as a nutrient source, Burkholder: Are ciliates in your Thalassia beds? Oppenheimer: Yes, very abundant. There are ciliates and just about every- vs Davis: Burkholder: Davis: Pomeroy: Burkholder: Vallentyne: Burkholder: Vallentyne: Burkholder: thing you can imagine, and incidentally, if you take the Thalassia leaves and strip them off you will find a symbiotic effect here with one species of diatom of which we have not determined the name. This one species of diatom lives in crevices on the sur- face of the Thalassia. When you strip off the outer membrane and look at it under a phase microscope you will see that almost the entire surface is covered with this diatom. It is hard to know what special relationships you have here. Are the diatoms between the bacteria and the water, or bacteria between the dia- toms and the water, and which is feeding on which? It is a tre- mendous problem in ecology in which I think we should have more interest. We found 20 different species of algae on Thalassia. Sometimes six of them on top of each other. One of my students found 20 piled on top of each other. Is this a food chain or just mechanical ? It is mechanical - epiphytic. All these underwater plants have algae all over them. The plankton is nothing more than what is swept off of them. The number of species in Florida springs is sometimes between 20 and 30 epiphytic on one plant. When you mention the production of the Thalassia beds of course you are lumping in a production of aufwuchs. Do you think that is a significant part? Oh, it is a very large part of the total production of the Thalassia beds. There are so many green things there. I take it, from what you have said, that perhaps there has been something done recently on the role of vitamins in this relation- ship between the zooxanthellae and corals. Is that so? Vitamins are put into the solution in which zooxanthellae are cultivated in the laboratory now. They have to be put in appar- ently. Ido not know where they come from in nature. Do the corals themselves produce it (B,,)? I would not think so. I think they pick it up from bacteria in the water, We have made quite a study of the origin of vitamin B)> in water and it comes from two places: bacteria in the mud and the actinomycetes and bacteria in the water. I don't know of any animal that produces B >, if you want to call coral an animal. The animal part of the coral complex I should think would not be expected to make Bj2, so the bacteria must be filtered out by the polyps. Perhaps this complex situation gets the vitamins 74 Odum: Burkholder: Stevenson: Burkholder: from marine bacteria growing externally and there is enough for the polyp and the dinoflagellates. It is a very complex sym- biosis there. Did you get around to plating out the bacteria in the coral? Yes, the bacteria are in the stony part of the coral, down inside. You know a lot of people have come to Southern California to live and these people have come in such great numbers that the ocean is changing rather significantly, much to the distress of the fish people. We find that in the giant sewage fields offshore, where you have great numbers of bacteria of human origin, (coliform types, of course) one of the significant increases in the plankton are great numbers of ciliates. Normally in the oceans ciliates are relatively minor. So we can detect without any other para- meter a sample of sewage water or contaminated water by the great number of ciliates. At the same time we find that in these sewage fields phytoplankton increased perhaps two or three or even four orders of magnitude. We are not sure to what we at- tribute this except to nutrients maybe several hundred times greater than normal in these areas. One question then that this all leads to: would we expect to find vitamin Bj> as a trigger mechanism for plankton blooms ina sewage field? Yes. Ido not agree with some of this recent literature that Bj)? is not ever a limiting factor in the ocean. Iam sure it is, be- cause there are plenty of places where we can't find it. I could present you evidence for the ratio between the Bj>2 in the sus- pended particulate matter and that dissolved in the sea water, and there is a kind of ratio there that seems to excess. Often- times there is not as much in solution - not available, It is al- ready taken up by particulate plankton and adsorbed on the col- loids and so on, so anything that stimulates the production of synthesizers of B)7 would be of significance in the subsequent development of planktonic blooms and other organisms requiring B)2, for how would they grow as blooms if there were no B)2? Us PARSE e Lit THE SALT MARSH AS AN ECOSYSTEM, Discussion leader: A. C. Redfield Contributors: L. R. Pomeroy A. C. Smalley Vo IM, Ikea CIRCULATION OF HEAT, SALT AND WATER IN SALT MARSH SOIL by Alfred C. Redfield Woods Hole Oceanographic Institution The annual cycle of temperature in salt marsh peat has been measured to determine whether water moves through the soil fast enough to disturb the predictable relations expected if the water is stagnant. The distribution of temperature ina solid of uniform composition, when subject to a sinusoidal change in temperature at the surface is given by (Joos 1934): Yio. z. piseateoien’ in eas o (t- 2) where (S) = difference between recorded and average temperature o) = maximum value of Oat the surface max t = time since Ovrne occurred x = depth below surface @ = angular frequency (2 9T/period) m = thermal diffusivity The predicted relations are shown in Figures1l3and14which indicate con- venient methods of deriving the diffusivity, m, from experimental data, When plotted as in Figure 14the attenuation of the thermal wave is given by the en- velope of maximum or minimum temperatures and is described by the expo- nential term. When plotted as in Figurel3 the line describing the change in depth with time of the average temperature ( @ =O ) has a slope equal to the wave velocity = /zmw. Thus either term may be used independently to de- termine the diffusivity of the material, Measurements made in the marsh at Barnstable 100 yards from the high land where 4.5 meters of relatively homogeneous peat occurred conformed approximately to the predicted pattern shown in Figures l3and14. Prelimin- ary estimates of the value of v and m are given in Table 1 together with their accepted values for water. Determination of the density, specific heat, and water content of the peat indicate that the interstitial water in the marsh if stagnant would yield values about 20 percent less than that of pure water. 17 FIGURE 13 Temperature > i< 7 (oa /o oa / Pee = Se, E giv/am v5 eS Nean Temp, FIGURE 14 FIGURE I5 Figure 13 - Pattern of isotherms resulting from damped thermal wave. Diagrammatic. Figure 14 - Distribution of temperature in depth at successive times resulting from damped thermal wave. Diagrammatic. Figure 15 - Points: distribution of chloride in Barnstable salt marsh. Curves are calculated from equations discussed in text. 78 It is concluded that the rate of penetration of heat into the marsh peat is of the order of magnitude to be expected if the interstitial water is stagnant. The distribution of chloride in the interstitial water at the same site is given in Figure 15. The distribution suggests a steady state due to a balance between a downward movement of salt water by some form of eddy diffusion and an upward movement of ground water. If such movements occur they must be reconciled in magnitude with the conclusions from the temperature observations. The minimal vertical movement which might be considered is that re- quired to balance the molecular diffusivity of salt. This would result ina steady state distribution of chloride described by the equation: a & x yo where a is the velocity of advection upward is the molecular diffusivity of salt a S/5, is the ratio of chloride at the depth, x, to that at the surface. This equation yields curves which are concave downward but the fit is not good. An approximate fit as shown in Figure 15is obtained taking = = O25 emeyiscer If A is given the value of 107°, the diffusivity of NaCl,then @ becomes 2.5x 107" cm./sec. which is only 1 percent of the velocity of the thermal wave. If molecular diffusivity is the mechanism responsible for salt transport, the associated advection will have an insignificant effect on the thermal diffus- ivity. Arons and Stommel (1951) have developed an equation to describe the steady-state distribution of salt in an ideal estuary. Fresh water is assumed to enter a channel of uniform cross section at one end with a constant velocity, @, while salt water enters the other end from a source of constant salinity, Sj, and is mixed with the outflowing fresh water by an eddy diffusivity,A , ascribed to tidal motion, which diminishes in value with distance from the sea. The steady-state concentration of salt along the channel is given by AY) isis Q) in which F is a dimensionless parameter defined by 2 DA cag ake @ F (2) where L, is the total length of the channel, X is the distance from the source of fresh water, and r= Xa GL Equation (1) describes the chloride distribution in the marsh peat closely re) Table l. Vv k 2 cm/sec cm /sec Wistar 9° 2.2x 107? le eeclOn> 20° 2.4 x 10-4 1.4x 1073 Peat - from m Wave Velocity - warming 3,3 x 107° 2.8x 1073 -cooling 2.4x 107° 1.4 x 1073 Attenuation - - Sie 1073 v = Wave velocity k = Thermal diffusivity of water m <= Thermal diffusivity of peat Table 2. Depth ns Avia A A/k cms 0 1.0 214 64x10" 0.49 135 0.7 105 gelec 10 = 0.24 270 0.4 34 D0: lone 0.08 405 Oa Del Reese 0.005 A = fraction of total depth from till A = eddy diffusivity of peat a 2 S)s% 10-6 cm/sec k = thermal diffusivity of water. 80 if L is taken as its thickness, 450 centimeters, and X is the distance measured upward from the till underlying the peat. F is determined to be 2,14 x 10°A by equation (2). It is not unlikely that the peat acts as a wick, conducting water upward at about the rate at which it evaporates from the surface. BESTE SE this to be the rate at which sea water evaporates at 409 N., a=3x10 cm./sec., which is only one tenth the velocity of the thermal wave, and consequently would not greatly influence its determined value. Substituting this value in equation (2) the values of the requisite associ- ated eddy diffusivity, A, may be estimated as it varies with depth, + as shown in Table 2. Except close to the surface eddy diffusivity becomes sufficiently small, relative to the thermal diffusivity to have little effect on the observed values for the latter, The preceding considerations do not lead to unique solutions for the water motions. They indicate however that on reasonable assumptions the distribution of chloride may be reconciled with the observed thermal cycle on the assumptions that; 1. The interstitial water is very nearly stagnant. There is a movement of ground water upward ata rate not greater than that of evaporation, 3. The interstitial water is being mixed by weak eddy motions which decrease in intensity with depth below the surface. References Joos, G. -Theoretical Physics, New York, 1934. Arons, A. B. and H. Stommel-A mixing length theory of tidal flushing. dmeingic ING Gig Wo S745 Gul UOE IN. DISCUSSION Chapman: Iam most interested in the contribution that Dr. Redfield has given. It raises a number of important points I think. The first question I would like to ask him is the distance that these observations were made from a creek, because one of the im- portant things that we have found out, not only on the New Eng- land marshes but also on the New Zealand and British marshes, is that the up and down movement of water varies with the dis- tance from the creek, and results that you have obtained here might hold well for a certain distance from a creek. The ques- tion is, would they then hold for a greater proximity to a creek? The second point I would like to ask Dr. Redfield is whether he has any views on this: there are two effects on the water table 81 Redfield: of the marsh as I understand it, the first is the diurnal one which Dr. Redfield has mentioned, concerned with the ebb and flow of each tide, and that movement is more pronounced the nearer you are to a creek and it also, I think, depends upon the height of the tide that is involved. That is, if you are dealing with a spring tide I think the movement is likely to be greater than if you are dealing with a neap tide. There is, in addition to that, what I call the spring tidal cycle movement of the water table as well, and the diurnal movement if superimposed upon this spring tidal cycle movement so that during the neap tide period the water table will be lower in the marsh initially than it is at the height of the spring tidal cycle movement. Ido not know whether that is going to add a further complication to the picture that Dr. Redfield has outlined, and I would rather like to have some views on that. Personally the thing that interests me most is Dr. Redfield's statement that there is no substantial movement. His data indicate no substantial movement of the water table. I would have thought that there comes a point when you approach a creek where quite clearly there is a substantial movement of the water table. Whether using this technique you could find that point I do not know. Well, I take no exception to any of the things you have suggested. This was a job which was going to require a long time. I did not understand it at the beginning. I did not know very well what to expect. I selected a point which was as accessible as possible so that I could drive out onto the marsh on a road which was available. I was 100 yards from the foreshore, which was about halfway between the foreshore and the large creek which came in, and there were drainage ditches of course - the small mos- quito ditches, not very deep. I could find a more remote spot. I didn't think that was very important at this stage. The point is, if this is reasonable, you have an extremely convenient method of quantitating things from relatively few movements and obviously my next task is to go as far out in the middle of the marsh as I can and repeat at least some of these determinations. Just where the water table is, I think, is very hard to say. This is an asymptotic curve. Several feet in the marsh there is no detectable chlorinity. There is no sharp boundary line, There is, however, a place down here where you change very abruptly into glacial till with gravel, glacial stones and so on. It is in- teresting to remark that this mean temperature, which is about 10.5° C, and which is just about the temperature of well water, is just about the temperature of the bottom of these ponds which occur in depressions in the moraine - depressions below the water table - the water at the bottom of those ponds remains at about this temperature all summer after the thermal stratifica- tion begins. These ponds begin to stratify only when the surface temperatures begin to get above 10.5; so we have certainly tied 82 Davis: Bradley: Redfield: Bradley: Odum; it very closely here with the ground water. Of course, the ground water and this value here in the marsh should represent about the average climatic temperature. I would like to introduce the idea of an air block. In some peat deposits you get a layer of air between two water tables. It may not be apparent all the time but it is particularly true in the Juncus romerianus tops over Spartina bottoms. Sometimes the amount of water in many samples I have taken is almost down to the dry point in the layer between the two types of peat so that your thermal gradients would not be the same. I just wanted to mention the air block. It occurs in some peats. I am quite sure that that is true. I think there are differences of course in the character of material. There might very well be this sort of distortion. I have one curve which I made out in the Puget Sound area which is apparently quite atypical. One thing which I might mention in closing is that from this equation, knowing the value of m which we have determined, and knowing the period, you can find out how much a diurnal or weekly or two-weekly variation will penetrate. It works out that a two-week variation would be compressed to about 1/5 this. In other words the fluctuations associated with the two- week tidal period would become unmeasurable at about one meter. Those associated with day and night would not go down more than about six inches so that you have a method of deter- mining what these valuations are and furthermore you have a method of determining what the mean surface regime is without measuring it every day because if you get down here, your curves will give you a nice smooth sinusoidal curve, and if you know your attenuation, you simply calculate back, and very quickly have a very good picture of the annual trend without worrying about the short term variations. I have some figures that may be comparable or may not. The flat in which we measured the thermal conductivities does not drain out and water is still standing in the ripple troughs throughout the half tidal cycle. There is no peat over it. In other words this was a bare sandy mud, We got thermal con- ductivities of 4.4 - 4.6x 10 ~. I suppose this is comparable to your m. Yes, it is the same. It would be then about twice as great, The depth to which the diurnal temperature range went in mid- summer was almost exactly 60 centimeters. What is the depth there approximately on your graph of chloride ? 83 Redfield: Odum: Redfield: Odum: Redfield: Chapman: Odum: Chapman: Redfield: Chapman: It runs down to about 4.5 meters - 15 feet. How deep do the roots on the marsh plants go? Oh, the live ones go down 6 inches to a foot. So there is no possibility that your plants are drawing water from a fresher source ? I wouldn't think so. You have a very firm crust of living roots and then it is extremely mushy and fragmented. Indications are that the roots of salt marsh plants are in pretty saline water generally. On the coast of Texas as you come around from Houston or somewhere about halfway down, the marsh drops out. There are several possible explanations. Two of the most probable ones are that the tide is low along the whole coast and the inlets get less and the evaporation goes up. It is conceivable that where you do not have much marsh it is more sandy. You may go from a place where there is an underlaying with a fresh water table to one which is underlain with a more salty table. I have been thinking more about this and I take it that this is a peat or peaty kind of soil all the way down. Is it? All the way down. Yes. Well, peat has the capacity to retain water. It acts as a sponge. One of the difficulties which I encountered when I was working on the Boston marsh was the difficulty of using ordinary record- ers of the type I had used in England because the spongy nature of the peat retained the water. It remained saturated so that I would think that this kind of technique would only operate really effectively as long as there is uniform material down through your marsh, and if the marsh geologically is composed of sev- eral distinct strata which differ in coarseness or fineness of material, one would undoubtedly get irregularities in the curve which would be related to the marsh structure, For ex- ample, in the marsh I worked on in New Zealand, particularly where there is this layer of fresh water peat about a foot beneath the surface, we found that the movement of the water was almost entirely restricted to the peat zone and that there was no move- ment if your recorders were in the mud. As soon as you got quite a short distance through the peat, there was no movement in the water at.all in the mud zone, but if your recorder went into the peat zone then there was movement of the water. If the soil is entirely a peat and there is a source of water underneath, 84 Chamberlain: Redfield: Chamberlain: Redfield: Chamberlain: Redfield: Bradley: Redfield: then I think one can see, because of the spongy nature of the peat, that the water would remain relatively stagnant, and that such movements as occur would only probably be reasonably adjacent to the creeks. I have two questions. Will you say a little more about the phys- ical nature of the substratum below your 15 foot marsh deposit? It seems to be glacial till. I have worked in an area; each time I gol move 5 feet in sort of a grid pattern so as not to be dis- turbed by the previous bore hole. I have really sounded out now a considerable area. There are variations in depth, and every once ina while I hit a large stone. Every once ina while I can feel gravel. Sometimes the probe just stops abruptly as though I have gotten into something pretty hard not obviously too gritty. I think it is what you might call boulder clay, would you not, Dr. Bradley ? The other point. Would you describe the instrument you used to measure your temperature variations ? Yes. The instrument is a thermistor. I use a 1/2 inch steel rod. At the end I have put a little plastic point. I wrap this with tape pretty well, Then I fasten the thermistor on with tape so that I leave about an inch of its casing exposed. Then a flex- ible tube runs up to a micro-ammeter which enables me to read the thing. The thermistor actually is encased ina strip of 1/2 inch copper tubing such as you use for gas lines and the ends are pinched down. It is embedded in wax so as to avoid disturb - ances which might come from mechanical effects. Did you have any difficulty getting a thermistor which was appro- priate for this kind of work? No, I did not. I cannot tell you the properties of it because I was not interested in finding out, but I couid get those from the man who designed the instrument. The particular recording system we have used is not a very good one, and I hope to get one which is better. You see, these determinations depend on the precise calculation of the mean temperature. Iam quite sure that if I played with my data I could bring them into adjust- ment. It may be that I am off 0.2 degree in my estimate of the mean temperature, Is that decrease in the chlorinity due to underground fresh water flowing in the till? That is my thought. 85 Bradley: Redfield: Bradley: Redfield: Bradley: Redfield: Rubin: Redfield: Otherwise you would have no decrease in chloride at all, I suppose so, if this were over a rock bottom. I want very much to get a series of these out across this marsh and get out a mile or two in between large creeks, which would give a very good opportunity for surface water to come up, and see how the whole thing varies. Wouldn't you get some upward movement of water, perhaps geo- logically slow, from compaction of the sediments so that there is always a slight advection ? It would be geologically slow. It must be or you would not have compaction, Actually there is not much evidence of compaction in the column until you get within a foot or two of the bottom and then you get an increase in the mineral content and a decrease in the water content, Bringing geologic time into the picture, I was interested in whether or not there would be a lot of movement of humic acids in a bog and so I investigated one. This was ina kettle in glacial till in lowa. I had pictured a churning motion of the water in a bog taking humic acid from the surface and mixing it and having it stain the peat at the depths. This then would give you carbon of different age being introduced as a contam- inant to the lower section. So I took samples from the bottom and from different strategic places along the peat bog and sep- arated the humic acid from the cellulose with sodium hydroxide separation. After that I ran radiocarbon on the two. In the peat at the bottom the cellulose ran 11,400 years and the humic acid at that level ran 11,400. The next level was 8,000 years and the humic acid 8,000. The next level I had was 6,000 and 6,000 and there was no appreciable difference in the two fractions as far as our error of measurement which at that range was between 100 and 200 years. Ido not think that you picture a completely stagnant bog through 11,000 years. It may be that the humic acid has no way of getting into the structure of the peat, because it is already saturated, and this stuff is immediately washed off with the first washing, but at least I must revise my idea ofa churning bog with complete overturning. I think that comes out to something like 5 feet a year. You see it is a very slow movement. It is all essentially in one direction so that soluble materials produced down here would tend to be very generally carried up and swept away. For example, this material does not impress me as having hydrogen sulphide in it. 86 Odum: Redfield; Odum: Redfield: Hayes: Redfield: Hayes: Redfield: Hayes: Redfield: Hayes: Redfield; Hayes: Redfield: It does not smell strongly the way muddy patches on the shore smell, It is pretty nice stuff, so I think that hydrogen sulphide and other things that are produced there are very gradually re- moved so it is all pretty well washed out. The water that is coming down is anaerobic, apparently, and it is coming up an- aerobic. Itis a stream of anaerobic water washing away the products of anaerobic decomposition. Is it a fertilizer? Is the fresh water a fertilizer ? I don't know what nutrients there are. Ground waters would be rich. Yes, I suppose there would be a certain amount. Iam not sure, however, what that would be on Cape Cod. Is the diffusion of salt out of the surface waters an appreciable factor that could enter in. This would be proportionable to the difference in salt concentration rather than to the difference in temperature and would drive the salt out of the surface waters and I suppose down into the depths. Well, this calculation was based on the idea that the salt was diffusing down by molecular diffusion, which can be measured. Is the temperature term appreciable in that? Oh, I suppose so. There did not seem to be a temperature term there and I pre- sume the temperature is warmer at the surface. Well, half the year it's warmer, the other half it's colder. You just left that out. Well I left that out because it is the powers of 10 which will show you whether there are large or small effects, and when I have got that straight I don't worry too much about this number, Is it possible to put a tracer like flourescein on the water table with the rocks underneath and have it move over and up? Well, I suppose you could do that and come back in three years and some of it ought to be up to the surface. Yes, that would be perfectly feasible but, of course, you do not know whether it is moving this way or whether it is moving that way. I mean it might not come up in the hole you put it down. 87 PRODUCTIVITY OF ALGAE IN SALT MARSHES by Lawrence R. Pomeroy University of Georgia The surface layers of the sediments in salt marshes contain a diversi- fied population of algae, Pennate diatoms of many genera and species are abundant. Dinoflagellates, green, and blue-green algae are also present. Al- though the algal population of the marshes is inconspicuous, and the standing crop is small, the rate of growth of the population is rapid, and growth con- tinues throughout the year. The amount of energy transformed by algal photo- synthesis is a significant contribution to the total primary production of the salt-marsh ecosystem. Photosynthesis of the marsh algae was measured under bell jars filled with filtered, boiled estuarine water (by change in oxygen content of the water). When the sediments were exposed to air at low tide, photosynthesis was measured by pressing transparent plastic boxes into the sediments, passing air through the boxes continuously, and measuring the change in carbon di- oxide content of the air with CO2-absorption columns. Measurements of photosynthesis were made at various elevations on the side of a natural levee beside the Duplin River, a tidal drainage creek. These were taken to represent production in other areas of the marsh having similar elevation, density of Spartina, and temperature conditions. Under- water production reaches a peak rate of about 200 milligrams of carbon fixed per square meter of marsh surface per hour (gross algal production: the total primary product of photosynthesis) during August and drops to about 50 milligrams in winter. For periods when the marsh is exposed to air a peak rate of about 150 milligrams is reached in January. Production drops nearly to zero in March, and gradually rises again through the rest of the year. Daily rates of production were estimated from the short-term (1 hour) production measurements by correcting for day length and the amount of time various parts of the marsh are exposed to air and flooded with water during a tidal cycle (Table 1). From the daily production estimates an estimate of annual production was made which was weighted according to the amount of marsh in the study area having certain elevations and Spartina density. The mean annual production for Georgia salt marshes was estimated to be 200 grams of carbon per square meter (gross algal production). To estimate net algal production (total primary product of photosyn- thesis less the amount required for respiration by the photosynthetic organ- isms) it is necessary to separate the amount of respiration of algae from that of the heterotrophic organisms in the sediments. This can be done, because 88 virtually all of the salt-marsh algae are motile and migrate vertically. By choosing a time and place when the algae have migrated to the surface, they can be scraped off almost quantitatively. Respiration of the scraped area can then be compared with an adjacent undisturbed area. When this is done, all the respiration measured, within the limits of the method, is non-algal. Therefore the data for gross algal production must also serve as approxima- tions of net algal production, and the difference between the two is probably less than ten percent. Respiration of the sediments community amounts to about 100 grams of carbon per square meter per year. Short-term rates are 13 milligrams of carbon per square meter per hour under water and from 10(spring) to 50 milligrams (winter) in air. Table 1. Weighted mean gross algal production, milligrams of carbon fixed per square meter per day, for periods of two months. Month: I-i Ui-IV V-VI VU-VIill IX-xX X1I-xX0 Production: 443 237 435 780 -- 714 Net production of the sediments community (excluding Spartina and macroorganisms such as snails and crabs) is about 100 grams of carbon per square meter per year. This is the production by algae less the respiration of the algae and the heterotrophic organisms in the sediments: bacteria, nematodes, protozoa, etc. The amount of solar radiation reaching the sediments proves to be one factor limiting algal production in salt marshes. Radiation was measured with a Whitney photometer both in air and under water. When the marsh is exposed to air, light intensity is above the optimum for photosynthesis except under dense stands of Spartina. This will limit photosynthesis, particularly in summer. When the marsh is under water, light intensity is within the op- timal range over much of the marsh. This shows us why production in air is at a maximum in winter when radiation is at a minimum, while production under water is at a maximum in summer when radiation is near its maximum. Photosynthesis varies with temperature when the algae are under water and light is optimal, but it does not vary with temperature when the algae are in air, because light is above the optimum. Temperature as well as light in- tensity may limit photosynthesis under water in winter and enhance it in sum- mer. This may explain why the maximum rate of photosynthesis under water is in late summer rather than spring. There is no evidence that the supply of carbon dioxide is limiting to underwater photosynthesis, but it may sometimes be limiting to photosynthesis in air, The pH of the surface of the marsh sediments rises from an early 89 morning low of about 7.5 to 9 or even 10 during the day. At pH 9 there is no free carbon dioxide in the interstitial water of the sediments and at pH 10 there is no bicarbonate either. Under these conditions the only sources of carbon dioxide for photosynthesis are the respiration of heterotrophic organ- isms in the immediate vicinity and diffusion from the air or the depths of the sediments, Considering only the algal production and ignoring the Spartina, the primary productivity of the salt marshes is comparable to that of many other aquatic ecosystems, such as lakes and the oceans. It is lower than many terrestrial and some flowing aquatic ecosystems. DISCUSSION Burbanck: Did you notice that the hydrogen sulfide formation in your marsh seems to be limiting at all? Pomeroy: That is something I have not done a thing with. Oppenheimer; Hydrogen sulphide apparently is not, because the algae will grow right in the hydrogen sulfide layer. It is just as product- ive as anywhere else. McHugh: Just as a matter of curiosity, have you figured out this pro- ductivity in terms of tons per acre ? Pomeroy: I cannot give you that offhand, Odum: Multiply grams per square meter by 10 and you get pounds peracne. Pomeroy: Well it is 200 grams per square meter per year. Odum: So that would be 2,000 pounds per acre. Chapman: What exactly do you mean by estuarine water? You said that you covered it with estuarine water. Is it brackish? Pomeroy: I took water from the immediate situation so I wouldn't be sub- jecting these organisms to a sudden change in salinity. Iam sure they are tolerant to it but I didn't want to introduce this possible variable, so I just collected water from the spot near- by and took it to the laboratory, filtered it and boiled it, sol would have no phytoplankton production and a minimum turbid- ity in the water. Chapman: You do not know what the salinity was ? 90 Pomeroy: It varied. Chapman: One other question. I am wondering whether your production underwater in relation to light is really completely valid, be- cause it is the quality of light rather than the quantity that matters under water. Your whole spectrum changes with depths. The usual technique, I think, when one is measuring algal productivity under water, is to measure it in terms of energy received rather than in terms of light intensity which may be entirely misleading. Iam just wondering what results you would get under those circumstances if one measured it in terms of light energy received. Pomeroy: I would like to hear some other opinions on that. I wonder if it is not a rather thin layer of water that we are talking about? It is a meter or less. Chapman: Well, I think the spectral composition is supposed to change rapidly even within a meter. What one really ought to get at I imagine is an acticn spectrum for your diatoms at the depth of water in which you are operating. Odum: The photometer he has does cover the spectrum of the action of photosynthesis and judging by what precedent there would be for diatoms there is no reason to think that there would be a great difference between the kind of measurement you would get with a photometer and the kind of action spectrum. One would be perhaps straighter than the other but your orders of magnitude ought to be the same, Moul: Isn't there a piece of work that shows that the other pigments in diatoms pick up energy from light in the position where chlorophyll does not and that you would get a plateau of photo- synthesis from diatoms. The work was done on the Pacific coast. And you are using clear water - filtered water. Pomeroy: Wels, Miltered) watex. Moul: I do not think this makes much difference. Pomeroy: I do not really either, but I cannot satisfy the criticism because I do not have an action spectrum. Ido not have an energy value, just a light value. Odum: On the subject of light that is one of the main ideas you have advanced. Let's see if this is right first, that what controls this is whether they are getting the right foot candles, say 800 or 1,000 foot candles. 91 Pomeroy: Odum: Pomeroy; Odum: Pomeroy: Odum: Pomeroy: Moul: Pomeroy: Moul: Pomeroy: Within the optimal range. And thus both seasonally and vertically and with the tide you have high photosynthesis when this happens. Now don't these diatoms move in and out of the mud as you have described them ? The migration is pronounced on the bare strand at the bottom of the levees and on the mud banks around the creeks, When you get up into the Spartina and up into the marsh proper, I cannot detect any migration up in there; so I think that becomes rela- tively unimportant when you are talking about the marsh as a whole. In other words you wouldn't think that the plants would seek their own light level? They wouldn't have to go very far. They do not seem to be. They seem to be doing exactly the opposite, because they are coming up when the sediments are exposed. Maybe they are fighting each other and trying to reach the top, but that does not seem reasonable to me. There is something else controlling it. The mechanism is there but the plants are doing what is not good for them, The mechanism is there and if, while they have migrated to the surface, you put a box over them, they will go right down. Or- dinarily they won't go down until an hour to half an hour before the tide comes back, but cover them up and they will go right down. You can check this by putting black polyethylene right on the top. That heats them so rapidly they are killed. Then y ou have a control, and you can peel the polyethylene off and you have a nice brown or green patch as the case may be to compare with, At the base of the Spartina do you have here a skin of blue- green algae, like we have on the Jersey coast? Yes, and during the winter and early spring we get quite a lot of blue-green algae up on the upper parts of the levee and back in the marsh, That is not subject to this migration? As far as I have found, it is not, and I think as far as produc- tion is concerned that they are probably less important than the diatoms. I have made a few measurements on it and there is production there during a short time of year when they are very evident, but it is a short period. 92 Oppenheimer: Did you say the change in pH is a limiting factor: In the possi- Pomeroy: Oppenheimer: Pomeroy: Chapman: Pomeroy: Odum: Pomeroy: Odum: Pomeroy: Odum: Pomeroy: Odum: Pomeroy: Burkholder; ble limiting of COz, might this account for the migration? You remember that you found the organisms out in the mud flats right below the surface. It is very possible that right on the surface CO> is limited so they migrate back down into the sedi- ment to where CO2 might be abundant. They are migrating up during the period when they are exposed to the air, and that is when I am measuring this pH in air. That is when they are up there, you see. I was thinking of this effect whenever you go out on sediments you almost invariably find your green coloration about two or three millimeters below the surface. That is true up in the marsh but it is not true when you get down near the low tide level. Could I ask another question? When you had this setup on the marsh and you have got your water in the bell jar, does the water in the bell jar fall at all during the course of the experi- ment or is the mud so compact that the water stays in? It stays there. I throw it away if I have a hole or anything underneath which lowers the level at all. I discard about 50 percent of them for that reason. Is there competition between the winter which is mostly a transient population and your summer which is mostly a water population? I take it that is the case, You are suggesting that this is a different population? I am just trying to see if there is something else besides light. There might be a different population. into the taxonomy. I simply have not gone Wait a minute, start over. the water. You have a population of algae in Not in the water Iam using for my measurements. So that's out. That's out. How did you get the population out of the water? 98 Pomeroy: Burkholder; Pomeroy: Burkholder: Pomeroy: Burkholder: Pomeroy: Burkholder: Pomeroy: Odum: Pomeroy: Odum: Pomeroy: Odum; Pomeroy: Odum: Pomeroy: I took it to the laboratory, filtered it and boiled it. And that removes the COz so your CO z supply comes from the mud then, Well, I reaerate the water partially. I try to keep the gasses intermediate in there so I can get a good change of oxygen without supersaturation, but it is partially reaerated. Do you think that the COz might be limiting and regulated by the microorganisms in the mud through the different seasons ? Well, Ido not know. I think that is possible. There is respiration in the mud here. We tried to measure it. It is pretty low unless it is refortified from some source and the photosynthetic products I presume are not diffusing very rapidly from the algae into the mud, so one wonders about this complex relationship between the known photosynthetic micro- organisms mixed in with the photosynthesizers. That is a very interesting question, I think there is a problem that deserves attention. It certainly does. Could the winter decomposition of your grass be considered as releasing nutrients whereas in the summer the grass is com- peting with the mud algae ? As you know, I have been making some starts on a study of the phosphorous cycle out there and I find a maximum of both total phosphorous and phosphate in these marsh creeks in August, and in the winter it is about a four to one change. How about the mud ? I haven't measured them in mud yet, I cannot tell you. Is your winter respiration that you said was high, unexplainably so? As far as Iam concerned it is unexplainable. Is that a function of a greater number of diatoms in the mud ? I haven't been making any measurements of population density that lam satisfied with. I have not tried cell counts, although 94 Dr. Moul apparently has a working method for this now. I have been working with pigment extractions, but there are complications in the marsh where you get a mixture of chloro- phylls and chlorophyll degradation products. 95 THE GROWTH CYCLE OF SPARTINA AND ITS RELATION TO THE INSECT POPULATIONS IN THE MARSH!) by Alfred E. Smalley University of Georgia Spartina alterniflora Loisel is the dominant spermatophyte of the marshes around Sapelo Island, Georgia, usually occurring in pure stands of varying height and density. Clip samples were taken at frequent intervals throughout the year by R. A. Ragotzkie in streamside marshes, the area of highest pro- duction, and by the author in the relatively low production areas of high marshes. Net production was computed from the between-sample increases in the living standing crops and changes in dead standing crops (the latter pro- viding a partial estimate of grass which died in the interval between samples). The estimate of the average annual net production of the entire marsh was 973 grams dry matter per square meter or 4248 kilogram Calories/m*% based on estimates of production of each marsh type in proportion to the area occu- pied by each as determined from aerial photos. The seasonal pattern of dead grass which remains in the marsh shows that the marshes of higher altitude contain large amounts of dead standing grass the year around, while most of the grass growing along tidal creeks either washes out while still growing or after dying in the winter and fall. Decompo- sition of the grass on the high marsh takes place largely in situ; that of the streamside marsh largely in the waters of the creeks and sounds. The weight ratio, roots and rhizomes/living leaves, is approximately 1.0. Much of the below-ground material is dead. Below-ground production is not considered here. The pattern of Spartina distribution revealed by standing crop measure - ments suggests that the organisms which depend on the grass as a nutrient source fall into two categories. The first are those which feed on the living, growing grass. The second are those which utilize the grass after it has died, whether it remains in the marsh or is washed out into the surrounding waters. The latter group must consist largely of microorganisms. The decomposed and fragmented grass forms part of the detritus of the marsh-estuarine com- plex and in this form may enter the marsh again when the marsh is flooded by the surrounding waters. Observations and collections on the marsh show that the most important herbivores feeding on living Spartina consist of two species of insects. One is a grasshopper, Orchelimum fidicinium Rehn and Hebard (Orthoptera: Tetti- goniidae), occurring from May to September; the other a leafhopper, 1) lam indebted to E. P. Odum and J. M. Teal for help in this research, which was aided by a grant from the National Science FoundationtoE. P. Odum. 96 Prokelesia marginata Van Duzee (Homoptera: Fulgoridae), which occurs the year round, but is most common in winter. The Orchelimum population was sampled with a sweep net, and density on an area basis estimated by a modi- fication of the method of G. Beall (Ecol., 16:216-225). Prokelesia density was estimated by cutting off grass in a quadrat of known area and placing the grass and insects into preservative (this could be done without disturbing the insects); or by placing a paper bag quickly over some grass and introducing some paradichlorobenzene into the bag. In order to equate the organisms which differed widely in size, life history and rate of metabolism, energy flow was used as a basis for comparison (Table 1). Energy flow is defined as the total population assimilation rate which is the sum of the respiration of the standing crop and the production of new biomass per unit time. Respiration per gram at the temperatures of the natural environment was calculated from oxygen consumption-temperature curves of different stages as determined in the laboratory. Respiration was converted to Calories by the oxycaloric coefficient of V. Ivlev (Biochem. Ztschr., 275:49-55). Production was calculated for Orchelimum by finding mortality from a survivorship curve constructed from periodic population samples. The sum of the caloric content (from bomb calorimetry) of the grasshoppers dying in each sample period equals the total production, since none of them survive to overwinter. The production of Prokelesia was found by assuming a ratio of respiration/assimilation of 75 percent, which is ap- proximately true for a wide variety of animals (H. T. Odum, Ecol. Monogr., 27:55-112, J. M. Teal, ibid., 27:283-302). As may be seen from Table 1, the two major herbivores assimilate only 7 percent of the annual net production of grass. In comparison, the "utilization efficiency" of herbivores is 38 percent (Odum, op. cit.) ina spring community and as high as 81 percent in a marine zooplankton-phytoplankton system in the English Channel (H. Harvey, J. Mar. Biol. Assoc. U. K., 29:97-137). Itis suggested that a tidal marsh is similar to a forest in its trophic structure at the herbivore level, since in either case immediate consumption of the primary photosynthetic product is of less importance than its subsequent utilization and decomposition by detritus feeders and microorganisms. Table l. Production and standing crop consumption of Spartina in KC/m4/yr. " Orchelimum Prokelesia ‘Spartina _ fidicinium marginata alterniflora Energy Utilization (Respiration) cea 205 Production il 69 4248 (net) Assimilation (Energy Flow) 25 274 UA Mon Pe oer Uae ee LO Os See 2 00 or TF Net Spartina production uo ———— DISCUSSION Odum: Smalley: Odum: Davis: Smalley: Davis: Teal: Davis: Teal: Smalley: If you take the slope of the standing crop graph of living Spartina, not the dead, what would the rate in gms/unit of time look like on a year's basis? Would you get a net production excess at the time of appearance of dead material? Try to see from these graphs whether you can compute the rate of export of organic matter or not. I don't think you can say you are exporting organic matter from the marsh because export is a function of detritus in the water. I will not say that the Spartina marsh is a system initself. The matter of export in the salt marsh-estuarine system is a matter of sedimentation and export to the sea and I do not know that. From your graph it appeared that in the spring you had the fast- est growth - it looked like April. Taking your figure off the graph it works out to be 13 grams per square meter per day net growth and that isn't far from the maximum growth of Chlorella cultures in a steady state that Tamiya has reported in a recent summary. Thus it looks like marsh growth may be of the same order of magnitude as the best yields in laboratory photosynthesis. There is one factor that I have been wanting to mention that has not been stressed. That is the loss by simple oxidation. Any substance like peat or any inert substance or organic matter is going to lose weight. Ido not know how you are going to handle that. In this whole eco-system business, as you get toward the tropics you do not get any leaf mold at all, because in your trop- ical A horizon there is no A horizon at all. Another trouble is comparing underwater productivity with above water because you won't get oxidation under water and you will above water. So you take Tom Odum's figures for Silver Springs and your figures for these Spartina marshes, and you are comparing two entirely dif- ferent habitats. One is subject to oxidation without any apparent way of measurement. This does not make any difference in the production of the grass. No, but it makes a difference...... On what happens to it afterwards. That is right and you use the word ''decomposition". I will talk about that. We did not use the figure supplied from the graph's data for the bacterial decomposition. 98 Oppenheimer: Whether it is water or air should not make much differeice in Chapman: Smalley: Chapman: Smalley: Chapman: Smalley: Chapman: Smalley: Burkholder: the oxidation rates because the dissolved oxygen in the water certainly should not be a limiting factor. Therefore oxidation rates would be comparable with respect to the other parameters such as temperature, salinity, etc. I remember when I was up in Massachusetts we recognized two different varieties of the Spartina: the tall one which we called variety glabraand a small one which we called variety pilosa. The small one lived on the higher parts of the marsh and tall one in the depressions which were the results of what we called the "rotten spots'' and I wondered whether you got those two varieties down here or whether the taxonomists have merged them. There are no recognized types of Spartina from the taxonomists! point of view, and I do not know whether there are any real types or not, but I rather doubt it. We never transplanted any from one place to another. That would be the acid test. We have just been playing about with a seaweed and we found that we could distinguish populations very easily and readily where you got variations within populations by making use of what is known as the ''discriminant function''. This depends upon two variables that you can measure so that if you have two variables in a population which you can measure as, for example, height of plant or length of plant and spike, or something like that, which seem to vary, you can make use of the ''discriminant function" to separate your plants into distinct populations occurring in dif- ferent habitats. Now this relates to your first question. You see from our point of view we do not want to separate these things. I have no interest in trying to get as many different varieties as possible. I would like as few varieties as possible. The production is what interests us. Yes, but if you really have got different varieties, your production may be different for different varieties. We would just as soon measure the production first. Why not? Well, because you do not know what you are measuring production of. It does not make any difference. Production is production whether you are measuring short grass or tall grass. You can measure these things as you separate them by observation in the field. Measuring fixed carbon? Cy Chapman; Smalley: Redfield: Odum: Smalley: Yes, but you want to be certain that your population is uniform. Actually 1am saying this, to a certain extent for argument's sake; we do try to pay careful attention to the taxonomy of the organisms that we study, but it would be so much better if we would try to minimize some of the subtle taxonomic differences and measure the functional aspects of the thing. I would like to say in regard to Dr. Chapman's remarks, that the separation of the forms of Spartinais possibly not as clear here as it is in New England. The high marsh, on which Spartina appears as a dwarf form, doesn't seem to develop here except under exceptional conditions. However, at the north end of the island we saw some Spartina growing very high on some old rem- nants of peat which resembled closely the type of plant we have on the high marsh in New England. It was very interesting that your dead grass curve was still very high at the start of the spring and that it decayed all during the summer so that this accounts, maybe, for the higher phosphate in Pomeroy's samples which appeared in the summer time. Re- generation was poor in the winter because of the low temperature and regeneration came about at the time of the high summer temp- eratures. It is the same thing in New England. In the North At- lantic you just have regeneration from the winter mixing,the same time light increases,and you have a spring bloom. You might remember Dr. Burkholder's discussion yesterday. If you add the decomposition time of the grass in the water to the time that it takes the grass to wash out of the marsh I think you will find that these tend to equalize the amount of detritus in the water the year round. There is a considerable time lag in some of these things we do not show when we put these diagrams on the board. This all looks like it is happening instantaneously. 100 ENERGY FLOW IN THE SALT MARSH ECOSYSTEM by John M. Teal University of Georgia In order to evaluate the role of the salt marsh in the estuary-marsh sys- tem along the Georgia coast and to understand the trophic relationships of the various organisms living in the marsh, I have, with the admittedly incomplete data available, constructed an energy flow diagram for the marsh. The diagram in Figure 16 shows the energy flow in kilocalories per square meter per year and was constructed in the following manner: The value for total light energy was taken from Kimball (1929) and divided equally between the two primary producers on the marsh, Spartina alterniflora, and the algae living on the mud surface. The values represented by question marks have not been measured. Data for Spartina production were taken from measurements made by Ragotzkie and Smalley of the standing crop of grass in the Sapelo Island marshes. The data for the algae were taken from the paper by Pomeroy in this publication. The assimilation and transformation of energy by insects was taken directly from the paper by Smalley. The marsh grass that is not eaten by insects is changed into detritus by the action of bacteria. Data for the calculation of the magnitude of this step were taken from Burkholder and Bornside (1957). Fifty-six percent of the marsh grass is composed of material available for bacterial metabolism and of this, 20 percent is built into bacterial substance while 80 percent is respired. This bacterial action does not all take place in the marsh, but also in the waters flow- ing in and out of the marsh. A part of the detritus energy is extracted from the energy flow as far as the marsh animals are concerned by the feeding of aquatic forms. There are errors in this calculation due to incomplete use of the avail- able Spartina by the bacteria and to turnover within the bacterial populations. Bacteria, detritus and algae form the food of the fiddler crabs, snails, nematodes and mussels. The fiddler crabs' respiration was measured through- out the year at the temperatures to which the crabs were acclimated. Multiply- ing population size be respiratory rate showed that an average of 133 KC/m“/yr was respired by the crabs. Since crabs grow to adulthood in a out one year, production was taken to be equal to the maximum standing crop, an average of ZATl KC/m“/yr. The respiration of the snail population, 72 KC/m“/yr is from the work of Smalley and the production of 8KC/m4/yr was calculated on the assumption of a 10 percent growth efficiency arrived at by combining theoret- ical considerations with Smalley's measurements of the growth of young snails. Using the data of Kuenzler for respiration and population size of the mussels and assuming a complete population turnover in one year, I found the mussels re- spired 49 KC/m4/yr and had a production of 20 KC/m24/yr. From some prelim- inary nematode samples, and using data from Nielson (1949) for respiration and turnover rate, I calculated respiration of 43 KC/m#/yr and a production of 101 SNOOOVY STIVY sgvuyo Gnw NOILONGOUd ALINAWWOD Ls ~ Vids Love S Gnw Cf . ne t RS) Nis iogasni| ® SNSYM o OF -< ol SuadidSs SYAWNSNOOD "ah/ 501/04 ul 91e SornstTy ‘ysaeul j{eS pueTSs] OTedeg 10; weisetp moTT ASrouq of ‘QT eansty 4K/2W/9> Sn ee ee mes | Baie {01 gO! Ol 01 ,O1 201 0! ,Ol 1v3H 006‘¢61' it T 00z86s ooz/\ é 4 o u a c29I 3 ze ! S Er ErAES / 5 ol stivnslo a 7 alvidaLova oe VW © — SY es ~ - ABS ol 000‘009 SYAWNSNOD ol SY¥s9NdOud LHS9I1 102 18 KC/m*#/yr. These figures are shown added together in the diagram. The author's data provide an estimate for the mud crabs of 21 KC/m*/yr for respiration and 5. 3 KC/m4/yr for production. For the Clapper Rail, infor- mation from a study by Oney (1954) was used to calculate the respiration of 1.4 KC /m*/yr and production of 0.2 KC/m4/yr. In the absence of data for racoons, they were assumed to be about as important as the rails and the rail figures were used, The spiders, wrens and other insect predators were assum- ed to be as effective as the predators on the crabs, snails, nematodes and mussels and the ratios of assimilation, respiration and production for the latter group were used for the former as well. The activity of mud bacteria was calculated from the figures of Burkholder for the dry weight of bacteria per gram of mud, assuming the bacterial popula- tion to be self-liquidating. The primary producers are fixing an unknown part of the incident solar radiation, and 0.5 percent of it shows up as primary production. The primary consumers as a whole assimilate 48 percent of the primary production and trans - form 76 percent of that 48 percent into heat. By groups, the insects assimilate 7 percent of the standing crop of Spartina and transform 73 percent to heat. The detritus-algae feeders assimilate 10 percent of the food available to them, i.e., the algae, bacteria and Spartina left after the insects and bacteria have taken their portion, and transform 82 percent of their food energy into heat. Of the production of primary consumers, the secondary consumers assimilate 40 per- cent and transform 80 percent of that to heat. The marsh consumers as a whole transform less than half, 46 percent of the total primary production of the marsh. This means the salt marsh is producing and exporting enough energy to support a larger community than that living on the marsh. (Much of the bacterial action upon Spartina considered a part of the marsh system actually takes place in the water.) There is plenty of energy fixed in the salt marsh to support a large population of shrimp, fish and bottom organisms in the tidal creeks and estuaries occurring in the Georgia salt marsh region. Data of Ragotzkie show that production of the local estuarine plankton community as measured by oxygen changes is negative, indicating that most aquatic organisms must obtain their energy from some outside source, in the author's opinion the marsh. It is not suggested that the marsh is adapted to use less than half of the energy fixed there so that the aquatic organisms will have a source of food. The aquatic forms, because of the flushing of the marsh surface with every tide, have a large part of the marsh production brought to them before the marsh consumers have a chance to eat it. A similar relationship between marsh and associated waters would not necessarildy be expected in a region where the great extent of the marsh was not regularly flooded. 103 References Burkholder, P.R. and G. H. Bornside. 1957. Decomposition of marsh grass by aerobic marine bacteria. Bull. Torrey Bot. Club 84: 366-383. Kimball, H. H. 1929. Amount of solar radiation that reaches the surface of the earth on the land and on the sea, and methods by which it is measured. Monthly Weather Rev. 56(10): 393-398. Nielsen, C. Overgaard. 1929. Studies on the soil microfauna. II The soil inhabiting nematodes, Natura Jutlandica 2: 1-131. Oney, J. 1954, Final report, Clapper rail survey and investigation study. Georgia Game Fish Comm. 1954. 50 pp. DISCUSSION Oppenheimer: (comment during paper) I want to point out that detritus eaters have available to them material from all the other environments which may put in appreciable error because all the excretory products are available to detritus eaters because they are ad- sorbed on the clay and silt...... Davis: I thought I would just volunteer a little bit. The Everglades are the only closed system we have of any great extent, and some of the marshes in Florida are lakes which are contained systems. How much entropy you have in these systems I never did know. Teal: I know nothing about your Florida systems, but for the marsh nearly 2800 KC/m*/yr is the entropy increase. Davis: Some peat deposits about seven or eight feet thick have been es- timated to be 5,000 years old by C-14 dating. Nothing washes out to sea. You see, you have an essential difference between a salt marsh and fresh water marshes. Fresh water marshes are not losing anything except to the air. The rate of oxidation for peat exposed to air is about anincha year. You can calcu- late the B. T.U.'s and convert to calories on the basis of C-14 accumulation of peat in the Everglade marshes or the Poplar Lake marshes. I have done some of that and cannot account for that much because carbon peat has an average of 8500 B.T.U.'s per pound, It is a rather slow rate of accumulation of peat; eight feet of carbon peat would require 5,000 years. You could figure it out in a closed system of a fresh water marsh. You have an advantage over a salt water marsh. You have something to account for that last figure. That is what I have been worrying about. meat: Yes, that would be interesting to figure out and put in the same 104 Odum: Teal: Odum: Teal: Odum: Teal: Redfield: Ragotzkie: Teal: Burkholder: Redfield: terms so you could get that last figure. It seems to me that you have pretty good measurements or are about to get good measurements on the production and your in- sect consumption, don't you? You could state a limit of accuracy, it might be 20 or 30 percent, whereas your bacteria are based on a bunch of inferences. It might be 100,000 percent off. No, it cannot be 100,000 percent off. No, but what I was going to suggest, why not work it backwards ? Why don't you concentrate on the export ? This is Ragotzkie's problem and he is working on it but he has not got it yet. If you could get that, then you would have for the first time bac - terial activity in a community. That is right, it would be nice and it would be nice to work back- wards. You have these other measurements for the macrocon- sumers and bacterial activity could be found by difference and you would have a better estimate of it. How are you going to find out how much Spartina goes out to sea? There should be a lot of it. I don't know, but physically it is very difficult. The transport would be tremendous during storm tides. These would move out a lot of material in perhaps two or three months when there would be no net consumption. Of course if you are going to measure this when it goes out to sea - out of the sound - and then try to figure back to bacterial activity, to make this a complete system you are going to have to have data for all of the consumers in the sound and in the creeks. All these are extracting energy too, and we do not know anything about these yet. Isn't a lot of this detritus being sloshed back and forth by the tides? It goes off the marsh and back again on the marsh. I think it is a very complicated business. Very complicated indeed. A single net wouldn't do it. Perhaps you could work back and forth with two nets. I would suspect it was a substantial quantity because here, as I see it, this stuff breaks off. It tends to stay in the creeks, with us it goes right up over the top of the marsh and deposits along the highland shore, but Iam sure that part of it goes out too. 105 Teal: Redfield: Ragotzkie: Redfield: Andrews: Teal: Wagner: Teal: Ragotzkie: Smalley: Ragotzkie: Smalley: Russell: Most of the loss is probably in the form of detritus. That is, very small particles. I don't think we lose much in the way of big pieces, Don't you ever find rafts of it floating around ? The rafts are primarily stems and the leaves are probably either decomposed by bacteria or mechanically broken up and take their place in the detritus which then merely become suspended mat- erial. It is very impressive to see the rafts. They appear as far as 10 miles to sea, but the nutrient value of these rafts is probably quite small because it is mostly cellulose stems. I think it would be more interesting to work on the losses into the mud, I gather that half of the vegetation is roots and that certain- ly doesn't wash away very fast but it will accumulate. If you knew the rate of growth of the marsh, then I would think that the contri- bution to peat would be a very small proportion of the free living plant. In Virginia we seem to get cycles of four good seasons for oysters, that is, for plankton, which is apparently related to a heavy runoff of water. Is there any mechanism by which the marshes might be built up in dry years and destroyed by storms? Do you know any- thing about the energy changes over a period of years rather than just a single year? No. Do you find much of a problem with manatee grass or turtle grass and some of those things washing in and piling in windrows on the marshes adding, I would think, considerable detritus from an out- side source ? I have never seen it here, I want to ask Al Smalley if he will comment on that annual varia- tion of production by Spartina. Don't we have some information on that ? I have some information on the high marsh but I think that by the time you consider that the production there is low and then you consider the production over the whole marsh this becomes small. But it does vary. Oh yes, there is variation. In your curve between July and October you have an increase in 106 the amount of dead material on the high marsh. I think that some of it has drifted in there, hasn 't it? Smalley: This is standing dead grass. The green grass is growing and dying at the same time. The outside leaves die or individual stems die. That increase in dead grass reflects production and I entered it into the total, 107 ARS SV) SALT MARSHES AS HISTORICAL RECORDS, Discussion leader: E. S. Barghoorn Contributors: J. R. Vallentyne H. M. Raup F. Johnson W. Schafer W. Hantzschel PALEOBOTANICAL STUDIES IN SALT MARSH DEPOSITS WITH SPECIAL REFERENCE TO RECENT CHANGES IN SEA LEVEL by Elso S. Barghoorn Harvard University The discussion in this paper pertains to studies of the plant remains found in a sedimentary complex exposed intwo building excavations in the Back Bay area of the city of Boston. This study involved the identification and ecological interpretation of both naturally occurring plant deposits recorded in peat and marine silt, as well as archeological specimens of wood intruded by human agency into the sedimentary complex. The deposits also provided unusually favorable material for histo-chemical study of degradation of plant remains under relatively well understood environmental conditions of deposition. The Back Bay sediments provided a basis of correlating vegetational changes ina complex estuarine environment, featured by a rising sea level, with an absolute chronology secured more recently by radiocarbon dating. The general sequence of events is interpreted as follows: 1) deposition of a marine (?) blue clay fol- lowed by sub-aerial erosion of the clay and subsequent intrusion over the eroded clay of sandy outwash(?) deposits. The age of the blue clay is unknown but is probably of late glacial age and is featured by ice rafted boulders; the sandy outwash deposits are probably of periglacial origin. Wind cut pebbles occur at the base of the sands. 2) development of a fresh water swamp forest featured by stumps of trees and shrubs (Quercus, Ulmus, Cephalanthus, Ilex, etc.). The forest was drowned by rising water with development of a fresh water reed swamp (Phragmites-Corex association). The fresh water reed swamp is dated as 5700 © 750 yrs. B.P. and is 20 = 2 feet below present mean low water of Boston Harbor. 3) inundation and termination of the fresh water swamp by marine waters with development of a short-lived salt marsh featured by Spartina alterniflora. 4) deposition of marine silt until the period of development of the city of Boston by European colonists subsequent to 1630 A. D. Within the stratigraphic sequence the following radiocarbon dates are re- corded, with their relation to the encroaching tidal plane: 1) fresh water reed- swamp peat at 20+ 2 feet below mean low water = 5700 750 yrs B.P. 2) human activity, represented by numerous stakes and wattles of a presumed fish weir, at or slightly below 13 feet below mean low water = 4500 £130 yarse B.P. (Human occupation probably occurred over a period of centuries). 3) stream rafted stump deposited at 9-10 feet below mean low water = 3850 390 yrs. B. P. 4) current tidal datum plane = 0 yrs. Extrapolation of the radiocarbon dates, in conjunction with paleo-ecologi- cal interpretation of the plant remains, preserved in the Back Bay sediments indicates that sea level has risen in the Boston Basin at an average rate of 6.6 inches per century during the past 5-6 thousand years. There is, however, no definitive evidence that this rise has been at a uniform rate. 109 Identification of the plant remains recovered from the basal peat and the overlying human occupational zones, dated respectively at 5700+ 700 yrs B.P. and 4500 130 yrs B.P., indicates that climatic conditions were essentially comparable with those of the present. There is some cogent evidence, based on statistical representation of certain species, that the climate at the time of human occupation and construction of the Fish Weir was warmer than the present. An interesting and significant corollary to the sedimentary history and chronological interpretation of the Boston Back Bay sediments has recently been secured from studies in the Barnstable Marsh, a large salt marsh on the northern coast of central Cape Cod, Massachusetts. Extensive unpublished palynological studies by Patrick Butler, formerly a graduate student in Harvard University now deceased, showed that the plant remains of the marsh consisted almost exclusively of Spartina alterniflora and S. patens. A depth of 29 feet of salt marsh peat was encountered in the deepe st boring. Detailed pollen diagrams were constructed from several cores. The entire marsh deposition was directly controlled by the advancing tidal plane. Recently Dr. Meyer Rubin of the U. S. Geological Survey secured four carbon-14 dates from Barnstable Marsh samples submitted by Dr. A. C. Redfield. There are as follows, respectively with depth and age, 21 * 6 inches = 400 £100 yrs B.P.; 33 inches = 770 £100 yrs B.P.; 207 inches = 1880 £ 100 yrs B.P.; 327 inches = 5480+ 120 yrs B.P. Since the present surface of the marsh is close to the mean high water tide range it is apparent that the salt marsh accumulation represents an average rate of submergence of approximately 6 inches per century, a value remarkably close to that for the Boston Basin area sixty miles away, as recorded in the Boylston St. Fish Weir site. The data, although regrettably limited, would also show that the rate of submergence has not been uniform during the period of marsh development. From neither the Boston deposits, nor the Barnstable Marsh deposits is it possible to conclude that submergence has resulted from crustal downwarping or from eustatic sea level rise. DISCUSSION Redfield: I would like to make just one comment with regard to the sort of evidence that you get if you plot the ages against the depth of the peat. We have a core from the marsh at Barnstable from a depth of 325 inches with an age of about 5,500 years. It indicates a rise in sea level at a mean rate of 6 inches per century. A second core from a depth of 200 inches from the same boring has an age of about 1,900 years; giving a rise in sea level at a mean rate of more than 10 inches per century. One might conclude that this marsh had grown upward slowly from 325 to the 200 inch horizon, and then more rapidly to the present level. However, we also have a sample from Center - ville, on the opposite side of Cape Cod, with an age of about 2,000 years from a depth of only 70 inches, corresponding to a mean rate of 3.5 inches per century. I think the deeper sample from Barnstable gives reliable in- formation because the peat was from right above the clay 110 Barghoorn: Redfield: Oppenheimer: Barghoorn: Oppenheimer: Barghoorn: Rubin: bottom and there cannot have been any great vertical change in its position since its formation. Since the peat is soft and of high water content I think it likely that the sample from 200 inches has moved downward by compaction from the weight of the peat which developed above it, and consequently it gives an erroneous estimate of the rate of rise of sea level. A second difficulty arises from the fact that Spartina alterniflora may form peat at some depth below mean high water. Such peat would give an exaggerated estimate of the change in sea level. These difficulties would be overcome if a series of samples were secured from immediately above the substratum at a place where the rising sea level had permitted the high marsh to grow inward and upward over the slope of the upland. I hope to do this in the area from which the aforementioned cores were obtained. Well, I wouldn't object to the top 200 inches. I think that the compression factor would support those dates rather than upset them. My point is that one sample of peat has sagged, but the other sample has not. The rate of rise of sea level, and we would like to know the rate of rise, whether it is continual, gradual, reversive, or what, could be estimated by making a series of measurements of this type. Is there any evidence of animal fossil remains at the same depth as you used ? Which depth did you mean? In the peat. There was an extensive study made of the animal remains of the Boylston Street site. I would like to comment on the first portion of your talk where you show the cellulose decreasing tremendously with chemical decomposition. The lignins, however, stayed the same. In radiocarbon dating we are interested in migration of the carbon and so this is quite important. For the last few years, since, in fact, you showed me one of these slides back at Andover, we have been using the cellulose fraction, extracting the lignins and throwing them down the sink, with sodium hydroxide. Now, even though the cellulose decreases from, as you showed, 60 down to 3, it is still the cellulose that grew in the plant at that time. You are sure because of the cell wall remaining attached. The lignin, which stays in the same proportion can, with the rise in pH, move with the ground water, even though you say that it is hata immobile. The percentage stays the same, so even though the same percentage of lignins remains it is still safer, you would say, to date only the cellulose and to throw out the lignins. Barghoorn: I think so. I think you could even be more safe and say, what pH could you possibly get in nature. Anything that wouldn't come out in 2 percent caustic you could assume never did move. But you see ina salt marsh you have a whole lot of complicating factors. You have other things in the plant tissues besides anaerobic degradation products. You have on the surface a constant biological activity which provides stuff for immediate transport. A study of peat shows that the bulk of the peat or- ganic remains are degraded probably within a few years on the very surface under rapid aerobic processes. It is the stuff that gets down in underneath that is intriguing. That is what I was interested in. So much of our coal seams and lignites, etc. are quite probably deposited under anaerobic conditions. That is the only reason they are there, because they haven't undergone rapid aerobic oxidation. It is very complicated. Rubin: You say that Barnstable had a high alkalinity ? Barghoorn: I don't know. (Turning to Redfield) Do you have any pH measurements ? Redfield: Not on these. Burbanck:: I was just wondering, since I heard Ed Moul describe the vege - tation of Cape Cod, and certainly the two sides of the Cape seem to be quite comparable in their vegetation, whether or not anal- ysis where we have such a discrepancy in tide in a very small area with the same plants might help to point up the already ex- cellent evidence as to how things have been affected, because on one side there is a 2.5 foot tide and on the other side, 9. My other point is in walking down many of these estuaries on the Cape I come to an area almost devoid of life where, working with a Hayward dredge I find a jelly-like material. When this gets on me and dries, it looks like clay. I was wondering whether anal- ysis of this jelly, apparently anaerobic and full of H2S, might have some relationship to this clay which keeps cropping up all the time in all of these studies. In some of the places it seems to remain in a deep area or perhaps is left stranded by the changes in meanders. It is quite possible that peat would overgrow this material, and it would remain there and be consolidated with the water being squeezed out, Barghoorn: Is this organic ? Burbanck: Barghoorn: Burbanck: Odum: Barghoorn: Odum: Barghoorn: Odum: Barghoorn: Odum: Barghoorn: I have never seen your analysis of it. I would judge from the composition of it that it seems to be organic and I was wondering if it may not be some of the extracts of the plant material that you have been talking about. These jellies occur ina variety of sediments both recent and old. There is a possibility that they have colloidal systems. Still, it is right between your deposits of sand in the headwaters and where the sands from Buzzard's Bay have been moved in from the mouth. It is intermediate. It is pretty much devoid of life. Macoma baltica is about all you find in it. What is known about the antibiotic properties of peats, both from the organic antibiotic types and also for the inorganic; that is, are the metal ions concentrated perhaps by the plants and sub- sequently further concentrated. What lam getting at is, you know the terrible range of trace element concentrations in coal. It seems to make no sense in terms of anything we know about modern plants. What does this mean, and does this affect the decomposition? Well it is a very involved problem. Your inherent ash, your clastic ash, your solution ash, and all of those things, but as far as the antibiotic properties of peat are concerned they are highly bactericidal. Do you think it is an organic antibiotic or an inorganic antibiotic ? It must be organic. Now do you have an entire range of this property or different north-south latitude effects or anything of that type ? (He refers to the very high levels of antibiotic activity in bogs which are present both in Europe and in North America.) As far as the minerals in coal are concerned, this is very difficult. Secondary post-deposition problems come in. The uranium bus - iness is trying to help the picture. The inherent ash in coal probably has little to do with the ash content. What is the humic material in the streams that are acid, such as the Gulf and southeastern coastal plain? I do not know. I think a good deal of it is probably tannin. Ido not think it is humic. 113 SOME ASPECTS OF THE BIOCHEMISTRY OF MUD by J. R. Vallentyne Queens University Approximately 1017 grams of organic matter is annually synthesized by plants on the earth's surface. Most of this organic matter is degraded by ani- mals and microorganisms, eventually to carbon dioxide, which is then recycled in the biosphere. A small fraction of the synthesized organic matter is buried in sediments. Biochemical studies on the molecular nature of this fossil organic matter provide data bearing on temperature histories of geologic deposits, bio- chemical evolution, and the conditions of origin of petroleum and coal. Most of the critical work has been done within the past 10 years, and much remains to be done in the future. Apart from the demonstration of the presence of trimethylamine in salt marsh deposits by E. C. Shorey in 1913, no one has seriously studied the bio- chemistry of salt marsh sediments. Biochemical data pertaining to other types of sediment are reviewed here, focussing attention on fossil as well as recent materials. Degradation products of plant chlorophylls have been isolated from both freshwater and marine sediments by Corcoran, Orr and Brown. These workers agree that chlorophylls a and b and c only rarely occur in recent sediments. The most abundant green pigments in recent sediments are phaeophytin a and phaeophorbide a. Related compounds (desoxophylloerythrin and de soxophyllo - erythroetiophyrin) occur in sedimentary rocks and petroleum. These porphyins, which are chlorophyll derivatives, have been isolated from geologic materials as old as the Ordovician. Carotenoids have been found in virtually all recent sediments that contain organic matter. A-carotene, B-carotene, echinenone and rhodoviolascin have been identified. Carotenoids have not been reported to occur in sedimentary rocks or fossils older than the Pleistocene. Cellulose and other carbohydrates have been found in recent sediments, and also in lignites as old as the Cretaceous. Polysaccharides are hydrolyzed to polymers of lower molecular weight during the course of geologic time. Polypeptides and amino acids have been found in recent sediments and in sedimentary rocks and fossils dating back to the Devonian. As with the poly- saccharides, the molecular weights of proteins decrease during the course of geologic time. Recent work by the author has resulted in the isolation of microscopic 114 pyrite spheres from sediments. These spheres have a mean diameter of about 10 microns, and have been identified as pyrite on the basis of solubility tests and X-ray diffraction patterns. The spheres are formed in recent sediments, as evidenced by their occasional presence inside dead plant and animal cells in the sediment. Pyrite spheres were isolated from a Spartina salt marsh deposit on Sapelo Island, Georgia. The method of isolation was based on the separation of heavy and light minerals in tetrabromoethane (density = 2.95). The heavy mineral fraction mostly consisted of the pyrite spheres. tS ARCHAEOLOGY AND SALT MARSH PROBLEMS IN THE TAUNTON RIVER VALLEY, MASSACHUSETTS by Hugh M. Raup Harvard University Forest This paper reports the botanical phases of a collaborative study made by Frederick Johnson and the present author at an archaeal jeice site on Grassy Island. The essential features were published in 1947 ’, and are only sum- marized here, with some revisions in the calculations of the age of the site. Grassy Island is situated in Smith's Cove, a small abayment of the Taunton River estuary in southeastern Massachusetts. It is entirely covered with brackish water marsh, which grows on the surface of the mass of salt marsh peat of which the island is composed. This peat rests in turn upon the shallow, level to very gently rolling, bottom of the cove. The bottom is made up of glacial till and outwash deposits. The tidal range at the Island is approx- imately 2.8 feet, and ordinary high tide bathes the surface. Spring tides some- times cover it entirely. Mean low tide is approximately at the base of the peat. The main channel of the Taunton River is close to the western shore of the cove. Interest in Grassy Island stems from the presence at the base of the peat of an archaeological site containing an abundance of stone tools and the remains of hearths. A basic purpose of our studies of the island peat and its present vegetation has been to date, if possible, the time at which the site became un- inhabitable to Indians due to the advance of the tide which now covers it. Certain assumptions are made at the outset because they appear to be re- liable and well documented. One is that there has been a continuous rise of sea level with respect to the land for some thousands of years, and that this rise continues. Second, it is assumed that the rate of rise has been relatively slow and steady, being at no time in the last 2000 years or so greater or less than the rate of accumulation of the peat, which is made up primarily of high-tide grasses. Third, the identification of the peat as being composed primarily of these high-tide grasses (chiefly Spartina patens at Grassy Island) rather than of mid-tide grasses (Spartina alterniflora) is held to be reliable because of readily observed differences in the preserved rhizomes of these grasses. Many borings of salt marsh peat in southeastern New England have shown that the accumula- tions are composed primarily of the high-tide species, and there appears to be no other explanation for this except one which involves a steadily advancing strand line. Furthermore, many of these marshes are underlain by some fresh water peat, indicating that at the beginning they were invaded by advancing sea water, 1) Johnson, Frederick and Hugh M. Raup. Grassy Island; Archaeological and Botanical Investigations of an Indian Site in the Taunton River, Massachusetts. Papers of the R.S. Peabody Foundation for Archaeology, Vol. 1, No. 2, 68pp. (1947). 116 The peat at Grassy Island proved to be anomalous in having only a top ven- eer of high-tide peat from one to two feet thick. Beneath this is a mass of re- worked peaty materials in which there is a mixture of high-tide species with some rhizomes of mid-tide grasses. The undersurface of the veneer of high- tide peat is a fairly even inclined plane sloping downward from east to west. Thus the high-tide peat is thickest on the western shore of the island, This shore is clifflike in formation, with the reworked peat undercut beneath the upper layer of high-tide peat. The east shore of the island is more gently sloping, and is covered with mid-tide grasses in its upper parts. It slopes into a mucky bottom below tide level. The nature of the two peats, and the manner of their deposit, were in part worked out in a nearby marsh which drains into the eastern side of Smith's Cove. Here it was found that the activity ofa meandering tidal stream (Shove's Creek), altering its course as the tide levels rose, had formed a "lens'' of mixed peat in the zone of the meanders. Apply- ing the principles observed there, it was found that the peat on the west shore of Grassy Island was being eroded away and carried around the ends of the island by tidal and other currents. It was being deposited as the mixed peat on the gently sloping eastern shore, Assuming that this process had been going on for a long time, it was concluded that the island had been changing its geograph- ical position and gradually migrating eastward. By this reasoning the western shore should be the oldest and should have, as it does, the thickest part of the high-tide peat. Comparison with a Coast and Geodetic Survey map made in 1875 indicated that the island had been moving its position at approximately seven-tenths of a foot per year. Again assuming that the advance of the tide levels has been fairly constant for a long time, it was thought that the slope of the undersurface at the high-tide peat (about 10 inches in 200 feet) would be a function of time and the rate of rise. Projecting this plane westward it was found to intersect the bot- tom of the cove near the eastern margin of the main channel of the river, about 1000 feet west of the east shore of the island. At the rate of 0.7 of a foot per year, the island would thus have started its migration about 1200 years ago. We have no figures for the contours of the bottom of Smith's Cove as of that time, but estimating that they were then approximately as they are now, the high tides would have begun to inundate the bottom of the cove above the main channel of the river about 1200 years ago. This would give an approximate date for the time at which archaeological sites located on the bottom of the cove became uninhabitable. Immediately following the time of inundation by high tide, the bottom of the cove must have been covered by a fairly continuous salt marsh. We believe that this marsh was for the most part removed by tidal currents as the water deepened, leaving only the ancestral Grassy Island and perhaps other small pieces of marsh peat which have since disappeared. DISCUSSION Redfield: I have just one remark to make which has not been mentioned yet and is pertinent with regard to the rise in sea level, That is WALT Raup: Barghoorn: Redfield: Raup: Marmer's studies of the tide gauge records along the coast. In Boston these go back for more than fifty years. In general they show a continued rise in sea level which was, in New England, at about a foot per century. I think that it should be borne in mind that we do have that rather positive evidence of what has happened recently. I tried to stay inside of the botanical evidence, Marmer's figures were approximately .02 feet per year from 1930 to 1937 and one-fifth of that rate in the preceding twenty years, which would give you a value that comes closer to your outside figure than this long range figure. These measurements are being re-examined by Walter Munk at Scripps. There is a simultaneous change in the mean barometric pressure for which apparently there are excellent records. This, I think, takes up a certain amount of the fluctuation of the curve, but Iam not sure that it cancels the general trend. There may be some quantitative readjustment of the trend. When we say that the change in sea level - the rise in sea level - has to be at about the rate of accumulation of peat we really don't know what we are talking about. By that I mean we do not know what the range of possibilities is. ARCHAEOLOGY AND SALT MARSH PROBLEMS IN MASSACHUSETTS by Frederick Johnson Phillips Academy New England Paleo-Indian hunters previous to about 8000 B.C. did not, as far as is known, utilize the sea shore. Much later aboriginal settlements, which can be attributed to an Archaic Stage of culture development, were built along the sea shore, inundated by a rising sea (with reference to the land), and in three instances, at least, were covered with deposits of salt marsh peat. The Boylston Street Fishweir, located some 40 feet below the street in Boston's Back Bay, is probably evidence of several weirs built along the shores of a bay when high tide level was about 18 feet lower than its present stand. When sea level was lower than this, the surface of the bay was covered in part by a forest and in part by a wet meadow. As sea level rose, the bay was flooded with salt water and Spartina alterniflora grew for a short period of time. The Spartina alterniflora was smothered by silt which also probably caused the abandonment of the fishweirs. Extensive studies of the geology, biology and chemistry of the underlying peat and the silt produced a wealth of information concerning the history of the development of Boston's Back Bay. Radiocarbon dates indicate that the fishweirs were built about 2500 B.C. Grassy Island, in the Taunton River estuary, is a peat island, the compli- cated history of which is described by Dr. H. M. Raup. The peat covered 499 stone artifacts and at least 2 hearths. The artifacts belong in the later phases of an Archaic culture which flourished along the coastal plain as far south as Georgia. Artifacts similar in many ways to the above had been found beneath 27 inches of peat at Stewart's Island in Marion Harbor on Buzzard's Bay, Massachusetts and under about 5 feet of peat at Grannis Island on the Quinnipiac River across from New Haven, Connecticut. The collaboration among botanists, zoologists, geologists, archaeologists and others in the study of sites of this nature produces data of wide interest and significance. DISCUSSION Russell: This work involved several things. It started up on Cape Hatteras and one of the initial problems was to find the Mason-Dixon line of Indian times. The northern Indians come down and stop very abruptly along the coast, not so much inland, but along the coast, 1) Johnson, Frederick and others. 1942. ''The Boylston Street Fishweir". Papers of the Robert S, Peabody Foundation, Vol. 2. Johnson, Frederick, Ed. 1949. ''The Boylston Street Fishweir II''". Papers of the Robert S, Peabody Foundation, Vol. 4, No. l. 119 Then our southern group which fits into our southern Mississippi chronology comes up along the coast and makes a break in the vicinity of Wilmington, North Carolina, which seems to have been very persistent. Now the significant thing that Haag did is an excavation at Savannah, Georgia. I think he had about 15 feet or so depth in the excavation. It was alongside of the river next to the wharf where, unfortunately, I had spent many days sitting on the deck of a freighter hoping to get out, not realizing that out there with- in a few hundred yards was this beautiful site that preserves practically the complete chronology stratigraphically, This has resulted in a monograph which Haag will, I think, finish in the reasonably near future. It is a case of a stratigraphic record for all succeeding cultures and he feels that he has started pretty well at the base of the series. I would like to add something about rates such as six inches per century and so on (rise of sea level) for New England, These disturb those of us from the marshes of Louisiana to some degree. We have middens and in a few cases definite mounds. In two cases we found effigy mounds, one deliberately designed in the shape of an alligator. We found 1500 feet of it with the head and one of the front legs removed. The rest of the alligator is perfect. Effigy mounds are rare along the southern coast. Local subsidence commonly lowers the base of a mound 10 feet or so below present sea level and yet involved in this is possibly 2000 years or less. It is mainly a matter of subsidence, but there is also the matter of compaction of the materials beneath, It is not too easy to distinguish between them but in a number of cases we have bored holes down through the mounds. Generally we will find shells at least two feet lower in the center than around the margin. For getting the floor upon which a mound was built we found that just by probing out from the flanks of a mound we would find the floor by hitting occasional shells. Perhaps in the first few probes we hit shell practically every time. Then out perhaps a hundred yards we now and then hit an occasional shell, and establish a nice level such as 8 feet below sea level. But at the hole in the center of the mound the base may be 10 feet below sea level. As we get out toward the distal ends of the old deltas of the Lower Mississippi River the mounds have gone down more and more feet, This is the same sort of thing that Eugene Smith pointed out around Mobile Bay years ago. So to think of 6 inches per century and to regard it as an always rising sea level gives us a little pause. Some rising of sea level, yes; some sinking of land, yes; but when you are in New England where glacial re- bound is taking place and the land is going up, you see you have 120 Barghoorn: Russell: a dilemma. Iam well aware of that. I would like, if we have time, to devote a few words to this. There is the matter of changing shells too. With us the Rangia cuneata is the brackish water clam; Unio the fresh water clam; and the oyster a more saline indicator. In these mounds we start out with one and wind up with another, even right through the sequence, and do this ina short time. The artifacts may all be of the same cultural stage. 121 ELEMENTS OF ACTUO-PALEONTOLOGY by W. Schafer Zoologisches Institut der Universitat Frankfurt More than 150 years ago some geologists perceived that only with know- ledge about present occurrences upon the earth could they understand the forms and physical events in the rocks of the geological past. With this perception a principle of research became effective, which puts a causal-scientific kind of view beside the historical one. Two men especially should be mentioned who realized the principle in their pioneer piece of work: the German, Karl von Hoff (died 1835), and the English- man, Charles Lyell (died 1875). ''The Principles of Geology'! by Lyell espec- ially is to be read with advantage to the present day. It ought not to be forgotten that long ago the artist and researcher, Leonardo da Vinci, and the mathematician and astronomer, Galilei, had ex- pressed similar thoughts, without being understood by their contemporaries, Of course, it was not by chance that the method of actual research by the study of earth-history was first discovered in the Renaissance. Mechanistic inter- pretation of the world began at that time. It was an approach which in the nine - teenth century achieved the success in natural science which is still with us. It was only in recent decades that institutes began this special task of studying the recent happenings in nature, The first such institute was founded at Wilhelmshaven on the southern coast of the North Sea by Rudolf Richter. Today others have followed on other coasts and in other countries, They con- sider themselves servants of geology and paleontology, though they investigate the occurrences and forms on the earth of today. We call them institutes of "Actuogeology and Actuopaleontology"'. As to the method, we use the direct observation of events. Because the work is in the present there is the possibility of experiment. The result is in all cases the knowledge of timeless laws. These laws in the hands of the geol- ogist and paleontologist cast light on the geological occurrences of the earth's past, and they give an insight into the past life and death upon the earth and into the environments of this life. Many rocks of the continent are born in the sea; therefore the examination of the seas of today is more important than the examination of the occurrences on the continent. Many rocks born in the sea have arisen in the shallow water of the shelf, therefore the examination of the shelf of today is more important than the investigation of the deep sea, So we see the actualistic research had its origin in the analysis of the V2Z beach and of the bottom of the shallow sea. Even today the mest important areas of research are the shallow waters with low tide and high tide, with limey, clayey, sandy, and organic sedimentation, and with a rich benthos. The Con- ference at Sapelo Island is at a suitable place for studying the formation of the flat submarine and intertidal deposits as well as the formation of the salt marsh of the recent geological past. In Germany work began on the convenient tidal flats of the North Sea. Here we have the opportunity of studying the laws of sedimentation with our own eyes, without using tools. These studies have now grown beyond the areas of tidal flats and advanced with new methods to the deeper and always flooded areas of the sea bottom. The change of the field of work became necessary because the tidal flats are geologically special cases and many a formation observed there must not be generalized. Every single observation is necessary and every analysis is an important part of the whole. But we must not stop with merely collecting details. After the collecting follows the putting in order, and, in its way, the intellectual penetration of the whole phenomenon is growing. In submarine geological research there are preformed arrangements and systems. In submarine paleontological research there are no such systems, This is so because actuopaleontology stands at the limit between biological and geological research. It draws from both areas, but it is nevertheless a whole. Here is an attempt at a system of actuopaleontological phenomena which we have been building in Germany in recent years. We distinguish four areas of submarine actuopaleontology: 1. The death of animals, their decay and sedimentation. 2. The behavior of life, formed as tracks and trails in the sediment. 3. Animals and communities of animals such as fossils of a facies. 4. Functional morphology of the animal's body. 1, The death of animals, their decay and sedimentation, With death a body is usually embeded, but not immediately or completely. It is mechanically broken up and chemically removed. It is necessary to under- stand the stages of destruction. All our knowledge of the forms of fossil ani- mals is based on the interpretation of such bodies embedded "at the vight time", The sooner a body is embedded, the more readable is the document of organic life in the rocks, but the later it is, the smaller is the prospect of reconstruct- ing the whole from the fragments. We find a series of questions: What can we know about the remains of the organic substance ? Is the body destroyed purely chemically or by bacteria ? How is a dry mummification accomplished and where? Is the destruction a total putrefaction with water and oxygen? What are the conditions of ZS; putridity in the absence of oxygen? What influence has the sediment in the destruction? Does a single organ- ism die, or when and where have whole biocoenoses been destroyed ? Do the skeletons stay in place or are they transported, and if so, where? How are the shells heaped up, and what quantities are necessary to form a rock with mineral oil? 2. The behavior of the life, formed as tracks and trails in the sediment, The organism forms a document of its existence in the sediment in two ways: a) as a body with its skeleton. b) as tracks and trails of a distinct behavior. Ichnology today is an important discipline, and many a rock shows its sub- marine formation only by tracks and trails made by organisms in the sediment. Particularly in this case a fundamental knowledge of the recent is the suppos - ition for the interpretation of the fossil. We recognized this very late, and all the gaps in our knowledge are larger as a result. Today we speak of ''fossi-textures'"' or "fossi-structures" of bedded rock, and we mean the texture or structure marked by boring animals and the changes which the beds have undergone because of the activity of the endobionts in the bottom. These changes can be figurative or may only deform the beds, The study of the endobionts is more important than the trails made on the surface of the sediment, 3, Animals and communities of animals such as fossils of a facies. CE RN SAIC NOB 8 ON A IES SAE AEA RS eI a NEI et eee Ecological research has for a long time shown the close relation between the animals and their communities and that a determinate community of ani- mals always points to a determinate environment. Thus we are also able in fossil cases to determine a part of a rock as a unity, and we are able to delimit it from another space of life which existed at the same time in the past. The geologist and the paleontologist speak of the "facies", and they mean it to be an epoch of the same conditions, the epoch not only delimited by the character of the sediments but also by a community of organisms which is called a "biofacies", The laws of facies and of its changing in sediments and animals can only be studied on recent sea bottoms. The phenomenon must be examined in its entire scope of time and space. 124 4, Functional morphology of the animal's body. The paleontologist has in his hands fossil animals mostly in the form of fossilized skeletal parts; so he has to give the definition of the animal from the anatomical parts alone. This is possible because all organic forms are limited in their parts and in their whole by their relation to a performance in an intra- or extracorporal environment. Each part is a logical allusion to a whole to which it belongs. In this fact the organism differs from all inorganic forms. The knowledge of the functional meaning of an anatomical part and of the whole is thus the key of all paleontological research, Relations of form to function are only to be explained by means of living animals in their natural environment ments. Thus functional morphology is one of the important disciplines of actuo- paleontological research, 125 TRAILS AND BURROWS ON THE TIDAL FLATS OF THE NORTH SEA AND THEIR PALEONTOLOGICAL SIGNIFICANCE by Walter Hantzschel Geologisches Staatsinstitut, Hamburg On the German North Sea coast tidal flat deposits are developed as a broad zone between the East and North Frisian Islands and the continent. The sediments of these tidal flats consist of mud, sand, and sandy mud. This tidal region, allowing observations of sedimentation and stratification phenomena, of the formation of ripples and other markings, is therefore a field of work for the giologist and also for the paleontologist. Few other regions on the coasts of the earth offer such a great variety of these phenomena. Numerous animals of different groups live on and beneath the surface of these tidal flats, leaving the traces of their activity: traces of their movement, of their feeding in the sediment or grazing on its surfaces, of resting on or dwelling in the sediment. These traces of their various actions are termed in German ''Lebensspuren", a term also used in this German form in Japanese paleontological papers written in English. They are generally to be defined as features in sediments left by living animals. Such trails and burrows are to be seen abundantly on the tidal flats and their study is the object of "ichnology': They are of great interest to the geologist and paleontologist, especially those occupied with paleoecological studies. In all kinds of sediments of all geologic ages and formations such "trace -fossils'' are to be found. There are many sediments in which trace -fossils are the only fossils found, and they are of some importance as proving autochthonous life in such deposits. The study of recent trails and burrows on our coasts, and particularly on the easily access - ible tidal flats, can help much to explore trace-fossils and to use them for paleoecological and paleogeographical investigations of fossil sediments and their environments. Ichnological problems have an only restricted interest for the zoologist; they have become - at least in Germany - a realm of the paleont- ologist. Such investigations may serve as a key for a correct explanation of trace-fossils. The history of paleoichnology shows clearly how the ignorance and disregard of neoichnological investigations led often to misinterpretations of trace-fossils. For some decades since the first descriptions most of them were regarded as marine plants, particularly as different kinds of algae. It was only about 1880 when the Swedish paleobotanist Nathorst and the American paleontologist J. F. James showed conclusively that the explanations of most trace-fossils as marine algae were erroneous. The following short review will exhibit what general and special results for paleontological and paleoecological investigations can be obtained from a detailed and careful study of recent trails and burrows. One of the most frequent animals of the German tidal flats is the well- 126 known lugworm, Arenicola. Its castings characterize especially sandy tidal flats during ebb tide. Newer investigations proved that their rather deep- reaching burrows are not always in the shape of a U but sometimes a J, These burrows often show a fine annulation directly under the funnel. Such impress- ions of the body are also to be observed on some fossil burrows from which we are able to conclude that they were made by annelids, and not be arthropods which also produce similar burrows in sand and mud. The burrow of Arenicola is a typical "dwelling burrow" (in German "Wohn-Bau" according to a proposal of A. Seilacher). Its upper end has often been somewhat consolidated by slime and even by ferruginous material. Such burrows can be preserved during the diagenesis of the sediments. From the German middle Triassic Muschelkalk of Bavaria we know trace-fossils represented by funnels and small flat cone- like elevations sometimes connected by a U-shaped burrow. They resemble closely the recent Arenicola funnels and castings. The bed with these fossils is to be found through a distance of about 25 kilometers and they can serve as guide -fossils for a special horizon. The name Arenicola has been used (some - times also erroneously) to designate different fossil burrows believed to be made by similar worms: Arenicolites, Arenicoloides and Archarenicola. Such burrows are by no means indicators of fossil tidal regions as supposed by some authors: Arenicola funnels and castings may be seen on the shore of the Baltic Sea on occasions when western storms blow back the water; this area is nearly free of tides. Another polychaete worm, Nereis, often produces trails resembling the form of antlers. Its locomotion trails are often branched or show small lateral branches, while the dwelling burrow of Nereis is represented by a rather complicated system of irregularly dug burrows one connected with an- other. The crawling trail is sometimes used several times by the same ani- mal and it can be observed to turn back in the same trail. Such branching of trails was formerly believed impossible for fossil worm trails. Before Nathorst's observations of branched recent worm trails branching was one of the chief ''proofs'' for the plant origin of most fossils called 'Problematica". On the coast of the Frisian Islands and on the coast of the Baltic Sea, meandering trails in form of a rather regular spiral were detected; some years later it was found that they are produced by the worm Paraonis. Only few ani- mals live in the sandy region of the surf. A little polychaete worm (Scoleco- lepis) was here observed by Seilacher and its ''Lebensspuren" are circular markings made by its tentacles while fishing with them for nutrient particles. Very similar markings are also known from Cambrian and Jurassic strata. Other worms living in the tidal flats or in somewhat deeper water be- long to the well-known Terebellids which build tubes (Lanice, Lagis, Sabellaria). There are many fossil counterparts in rocks ranging in age from the Paleozoic to the present. The little annelid Polydora boring a U-shaped burrow in the shell of pelecypods, gastropods etc., gives a good example for that which we call in German "Spreiten-Bau", By the continuously prolonged deepening of the U 127 there originates a system of U's ina U. Between the limbs of the outer U a "Spreite'" is formed which can be compared with the web of a duck's foot. Beginning in the Paleozoic we know such U-shaped burrows with ''Spreite", also in much more complicated shapes. In recent biotopes they are also known from other, non-marine regions and fossil occurrences do not permit a conclus- ion of fossil tidal flat regions, not even of marine environment. Among the arthropods the little amphipod Corophium leaves a variety of trails and burrows. Thus, in fossil state one would not ascribe them to a single animal. It makes two different forms of crawling trails, a smooth one and one resembling a string of pearls; it digs a little U-shaped burrow, either perpendicularly into the surface or horizontally into the walls of the tidal chan- nels. While feeding it produces a little, rather regular star-like feeding trail. The form of the burrow is not always a U. In sandy sediments, which are better ventilated than muds, the animal often digs a simple vertical shaft. The well-known Crangon offers a good example of that which Rudolf Richter termed a "resting trail" (or Kuenen reposing trail, in German ''Ruhe - Spur''). This arthropod is to be found hidden in small pools in the surface of the sand during ebb tide. It leaves there flat, uncharacteristic and usually transient troughs. Commonly they are oriented parallel to one another, be- cause the animals faced the current. This parallelism is a characteristic feature for this kind of trail which is also to be found in fossil resting -trails produced by some kinds of arthropods. Many different arthropods in the ancient seas have made various kinds of burrows, often rather characteristic - ally branched or expanded. On our tidal flats we know of no recent examples for such burrows as the screw-like trace -fossil Xenohelix from the Tertiary of North America. Only Carcinus can be seen, retired in burrows ending with a hollow which have been dug in the walls of tidal channels. Among the more sessile pelecypods only few traces of their activity are recognizable. Cardium seldom crawls and its trails are only short furrows on the surface of the sand. Star-like feeding trails can be observed which are made by Scrobicularia. This pelecypod, living about 5 inches below the surface of the tidal flats in sandy sediment, extends one of the long and separated siphons (the incurrent siphon) to the surface of the sediment. It produces rather regular stars when it draws in sediment from the surface in various directions. Such trails can be named (according to A. Seilacher) feeding or grazing trails, in German ''Weide-Spuren'', The siphons of Mya are joined together and they pro- duce rather large holes by which this pelecypod can be detected. Among the gastropods Littorina is often to be seen wandering over tidal flats, especially near high water line. Sometimes the trails are parallel for long distances and not seldom one animal creeps behind the other in the same trail. If one of them leaves the furrow, the trail becomes branched which is somewhat unexpected in gastropod trails. The gastropod Hydrobia is very a- bundant on the tidal flats but produces trails of no specialinterest. These are simple, smooth furrows which are irregularly curved and which resemble those produced by other little animals such as crustaceans. 128 What can be concluded from these tidal flat observations concerning the interpretation and exploration of fossil trails and burrows? Too many animals in their activity produce such similar traces that a morphologic distinction be - comes impossible. On the other hand as shown by the amphipod Corophium one animal is able to make such different trails that nobody would interpret them, found in fossil state, in a correct manner and ascribe them to the single pro- ducer. Therefore it is very difficult and mostly impossible to determine the producer of a trace-fossil with certainty. The forms of the trails depend not only on the special activity of the animal but also on the sediment, its charac- ter and state. There may be little chance for these surface trails to be preser- ved for the future and to become fossil, but we know such transient markings as ripplemarks well preserved after many years in eroded tidal flats. The study of recent trails of animals in the tidal flats has given some help in erecting a "system"! of all trace-fossils as proposed some years ago by the German paleontologist A. Seilacher. Such a classification cannot be founded on morphological features nor can it be based on the zoological system as shown above. It seems only possible to distinguish trails and burrows ac- cording to their ecological value and to elaborate common features of trails produced under the same ecological conditions. Such results of neo-ichnolog- ical studies which are to be extended to other marine and non-marine biotopes will help to evaluate trace-fossils better than it is now possible. They will probably also give some assistance to paleogeographical investigations. Ac- cording to biocoenoses "ichnocoenoses" could already be distinguished in some ancient formations, but such explorations are still 'in statu nascendi''. Itis also to be hoped that new methods and techniques in sedimentology will be de- veloped in order to detect recent trails made within the sediment which are also of greatest interest and importance for the paleontologist. DISCUSSION Vallentyne: I was wondering about the presence of these tracks in pre-Cam- brian sediments. Do they occur there ? Hantzschel: In pre-Cambrian sediments trace-fossils are only rarely to be found. There is an interesting newer investigation by A. Seilacher (Der Beginn des Kambriums als biologische Wende. Neues Jahrb. Geol. Palaont. Abh., 103, pp. 155-180, Stuttgart 1956); he collected and compared trails and burrows of the pre-Cambrian and of the Cambrian sediments of the Grand Canyon, Arizona. He showed that only very few and uncharac - teristic forms of ichnofossils are to be found in the Precambrium, while Cambrian sediments (also in Scandinavia and Pakistan) con- tain much more and more differentiated forms of trails and bur - rows. Oppenheimer: Do you know if any animal at all secretes any substance which allows the sand to become more permanently impressed because 129 Hantzschel: Redfield: Mc Hugh: Hantzschel: Davis: Hantzschel: Zeigler: Hantz schel; Chronic: Hantzschel: during the process of overlaying it seems more than likely that the track would be washed away. In my lecture I mentioned the slimy material only briefly. Trails of Nereis are often consolidated by slime and those of Arenicola by ferruginous material. Yesterday we saw the same phenomenon on the beach of Sapelo Island in the burrows of Callianassa,. I think this must be a prerequisite for consolidation before becoming a fossil. May I comment on your question? Some years ago I was inter- ested in the subject of marine fouling and one of the things which seems to happen almost immediately when any object is placed in the sea is that it becomes coated with a slimy material which is a film of microbial origin. I have often wondered if films of that type were not only present as they must be around all par- ticles of sand, if they did not tend to compact and bind together and give the sand a structure which it would not have if it were perfectly clean, and so add to the permanence of traces of this sort. I was interested in your remark about Littorina, how various individuals will follow each other along in the same path. I was interested this afternoon to watch some of them on the mud flats and to see how exactly one will follow the path of another and I wonder how they can do this. I was wondering about the mech- anism by which he senses that another one has gone before him. I don't know. Did you find more trails in calcareous muds than you did in non- calcareous? The reason for asking that is because carbon diox- ide given off by the body of the animal will help cause induration of sediments if you have calcareous material. The sediments of the tidal flats of the North Sea are mostly sandy, more sand and more clay, but no calcareous material, Have any studies been made of the amount of area ona flat which is turned over per tide by these trails and the amount of sediment which is stirred up? It is difficult to say. I think we have no quantitative data on this. Have any studies been made of the impressions of the bottom which algae or floating organisms might make in shallow water - say tidal flats ? These are things which we don't call traces but which in Germany 130 Oppenheimer: Chronic: Oppenheimer: Chronic: Oppenheimer: Odum; Hantzschel: Odum: Hantzschel: Odum: Schuckmann: Bradley: we call ''Marken''. We restrict the term, ''Marken'! or mark- ings, absolutely to inorganic things but it is possible that a crustacean moving over the surface leaves a trail or marking. There is a reaction which might be interesting to the understand- ing of these burrowing animals. That is when you have an an- aerobic sediment and sulphate reducing bacteria active, you get a lot of hydrogen sulphide produced and this creates an acid sed- iment. When the organism comes into there and burrows a hole, it allows the oxygenated water to penetrate. Then the anaerobic acid sediment is converted to an aerobic state and thus the pH rises. It is very possible under certain conditions in which there are carbonates dissolved in a more acid anaerobic part of the sediment that you will get calcium carbonate precipitated due to the change in pH around the side of the burrow. I was going to ask if that could happen to iron as well. Well, the iron is changed from the reduced to the oxidized state. Is it apt to be precipitated as a limonitic band ? It is already precipitated as the iron sulphide and it is converted to a hydroxide so you just get a change of state of the precipitate; instead of black it is red. Ido not know if there is any mobility of the iron although iron hydroxide in the ferrous state is sup- posed to be mobile at minus 200 millivolts in the anaerobic state so there might be some migration there too. Do you have any suggestion as to what graptolytes are? No. They are not tracks I presume ? They are preserved fossils which are out of discussion today. There is a very fine investigation of these by the Polish paleont- ologists. But it could be some secretion from something couldn't it? I think that studies of thin sections and so on indicate that that could not be the case. May I comment on Dr. Oppenheimer's observation? I can't say what the pH was in the mud that I studied but I had the opposite experience measuring the pH and eH in the tidal flats on the Maine coast where the sediment is reducing and there are sul- phate reducing bacteria and in none of those did we find that the 131 Oppenheimer: Bradley: Stevenson: Burbanck: Hantzschel: Burkholder: Hantzschel: Redfield: Burbanck;: Chronic: Hantz schel: PH actually did go below 7. How soon after you collected the samples did you read it? We did it in place. I might just comment on that. I found pH's similar to those that Dr. Oppenheimer must have found as low as 4.9 although that was extreme, but certainly well below 7 - in the 6 and 5 range. I just wanted to ask about Limulus. It seems to leave sucha good trail, but it was not mentioned, It is an old group and I just wondered if this came into the picture at any time in your fossil trails. Yes. You know the famous paper of Kester published in the German Paleontology, I think in 1938, on investigations founded on observations on the east coast of the United States. Itisa very good investigation of the Limulus trails. There are trails in the upper Jurassic of Germany. There are Limulus trails in, I think, the Devonian of Pennsylvania. In Germany in the famous upper Jurassic slates which preserve such wonderful fossils. I wanted to ask if anyone studied the trails and burrows made by animals in deeper water where the sediment is not exposed, for example, with underwater cameras, Not yet. There are only some submarine photographs taken by deep sea expeditions. In some cores taken by deep sea exped- itions there are also to be found such burrows, and sedimentologists ologists do not like them because they stir up the stratification and sedimentation. I would suspect that under water an animal would leave a very weak trail because most of them don't weigh very much. I think that Ewing's pictures of the holothuroidian left quite a good one, This brings up the big subject of dinosaur tracks and other ver- tebrate organisms which have had a tremendous amount of writ- ing in the literature. Have you made any studies of these or any possible paleoecological implications of these which concern the tracks of vertebrates ? We omitted the tracks of vertebrates. In Germany some distinct trails that were said to be made by dinosaurs we found were worm trails. 132 Redfield: I remember when I was a student, Professor Raymond showed us a large slab of sandstone with a curious trail. They were sort of moonlike depressions forming a string of beads and he told us that this was a complete mystery to the paleontologists. Shortly after that I went down to the sand hills, It had been pretty wet and there was a shallow pool among the sand hills and here was almost the identical track somewhat reduced in size. I followed it across the bottom of this pool and on the lee side there was a large log. Apparently it had been going across on the waves and every time it hit a wave it made a little foot- print. I think you will admit that this is a difficult subject. 133 i, ‘ “