Oceanus

VOL. VIII. NO. 1 SEPTEMBER, 1961

EDITOR: JAN HAHN

Published periodically and distributed to the

Associates of the Woods Hole Oceano-

graphic Institution and others

interested in Oceanography

HENRY B. BIGELOW

Founder Chairman

NOEL B. McLEAN

Chairman, Board of Trustees

PAUL M. FYE

President and Director

COLUMBUS O'D ISELIN

H. B. Bige/o--iv Oceanographer

BOSTWICK H. KETCHUM

Senior Oceanographir

The Woods Hole Oceanographic Institution • Woods Hole, Massachusetts

Nous verrons
que nous verrons

X

HIS might well be the motto of oceanographers. The men on our cover
leaning over the side of the R.V. 'Chain' to bring up a coring tube, are full
of anxiety which may turn to joy or to disappointment. After many hours
of waiting the instrument returned from a depth of 25,000 feet. "Did we
get a core? Did it trip correctly? Did we hit hard bottom?" We shall see
what we shall see. After another ten or fifteen minutes of struggle the
50 foot long steel barrel is laid along the deck and may lead to the
excitement so well described by Dr. Nicholls in this issue.

Editorial

VOL. VIII, NO. 1, SEPTEMBER 1961

l7OR once we have devoted an entire issue to just one cruise of one of
our research vessels. Cruise No. 17 of the R.V. 'Chain' (Captain E. H.
Killer) to the Romanche Trench on the Atlantic Equator was particularly
interesting in that a large amount of diversified work was done during
the 3l/2 months, 17,000 miles voyage. Measurements of the Atlantic
Equatorial undercurrent, the finding of a passage through the Mid-
Atlantic Ridge, the dredging of volcanic boulders and glass and many
other interesting observations were made by a total of 29 men (and girls)
in the scientific party; consisting of physicists, geologists, chemists and
biologists. In addition a new method of navigation was tried out, gravity
measurements were made and time exposures of the night sky were
obtained possibly for the first time. All in all 'Chain' 17 was a most
successful cruise.

Although the often oppressive heat did not make for the most ideal
working conditions the officers and crew of the 'Chain' assisted "science"
in the cheerful and co-operative manner in the tradition of the Institu-
tion's ships' personnel.

Porpoises jumping ahead of the 'Chain'.

CHAIN - 17

IN THE

ROMANCHE TRENCH

BY W. G. METCALF

A newly discovered passage through the Mid-Atlantic Ridge

and measurements of the Atlantic Equatorial Undercurrent

were some highlights of the cruise.

HE Romanche Trench Cruise was
conceived in the fall of 1958 when,
during the Equator Crossing of the
Atlantic Ocean on the R.V. 'Craw-
ford' as a part of our International
Geophysical Year studies, our curi-
osity was aroused by the results of a
7,000 meter hydrographic station in
the Trench. The Trench itself has
been known since its discovery by
the French Naval Vessel LaRomanche
in the last century as a geological
phenomenon of an extremely deep
hole lying directly on the mid-
Atlantic Ridge. The deep water of
the Trench, our Crawford Station
#482 showed, was of Antarctic origin
with a potential temperature of
0.65°C. and an adiabatic increase in
the observed temperature from a
minimum of 1.10° at 5030 meters to
1.37° at 7020 meters.

The Eastern Basin of the Atlantic
Ocean has considerably warmer deep
water temperatures than does the
Western Basin, and our IGY data
suggested that the coolest Eastern
Basin deep temperatures lay in the
vicinity of the Romanche Trench.
This led me to believe that this area
might be the saddle point of the
mid-Atlantic Ridge. One of the major
objects of the 'Chain' cruise #17 was
to check this point.

Hydrographic station on the 4-8 watch

We had hopes of an additional
course of investigation in the Equa-
torial Region which also stemmed
from our Equator cross-section in
1959. . . and that was to look for the
Equatorial Undercurrent such as the

one described by Knauss in the
Pacific and which he has named the
Cromwell Current. In the Pacific, the
Cromwell Current lies on the Equa-
tor running strongly to the east only
a few meters below a west flowing

Chain- 17

surface current. A Cromwellian
Current had not been described in
the Atlantic, but Gordon Volkmann
had suggested we look for it on the
Equator crossing by means of lower-
ing very small parachutes with the
BT winch to see if an east flowing
sub-surface current could be detec-
ted. Although only the crudest form
of observations were made by this
method, we were convinced of the
existence of such a current.

Bathymetric survey

In connection with the Romanche
Trench and mid -Atlantic Ridge
saddle point, one of the most impor-
tant things was to obtain as complete
a bathymetric survey as possible of
the Trench area. Therefore, the first
phase of the cruise consisted almost
entirely of echo-sounding work.
Originally this was planned to be
centered on the Trench inasmuch as
I was able to convince myself from
our scanty hydrographic data that
this was the key to the problem of
deep water communication between
the Eastern and Western Basins.

However, one weekend evening
J. B. Hersey called me up and
expressed considerable concern over
this plan. Existing charts of the area
are extremely poor in showing the
contours of the Ridge, and Dr.
Hersey feared that concentration on
the Trench might lead us to overlook
a possible saddle point he suspected
might exist a few hundred miles
further east along the Ridge. This
sent me scurrying back to the hydro-
graphic data files, and the informa-
tion derived certainly indicated that
it was a pretty risky proposition to
consider the Trench as the saddle
point. So it was agreed that the
bathymetric survey, which was car-
ried out by Arthur Voorhis and
Elizabeth Bunce, should be expanded
in scope to check the Ridge to the
East. This was done, and it saved
the day.

When I arrived in Freetown,
Sierra Leone, to join the 'Chain'
following the bathymetric survey, I

MR. METCALF is a Physical Oceanog-
rapher on our staff and joined the
Institution in 1945. He was chief scientist
on the second and third phases of 'Chain1
Cruise #17.

was greeted by a vast array of fatho-
grams and a wonderful three dimen-
sional plastic model constructed by
Charles Parker and Marvel Stalcup,
all of which indicated that Brackett
Hersey's weekend phone call had
paid off. The deepest passage across
the ridge apparently occurs not as a
deep cut at 18° west on the Equator
through the Romanche Trench but as
a series of meandering canyons and
mountain passes and gullies weaving
their way tortuously around isolated
mountain peaks and ridges in the
general area of 15° west on the
Equator.

Our study of the deep water com-
munication through this region
consisted of a series of hydro stations
extending across the saddle region
from the deep water of the Eastern
Basin into the deep water of the
Western Basin to determine exactly
what sort of water we were dealing

Three dimensional models made on ship-
board show the Romanche Trench area in
the background and the Trench details
in the foreground.

3CTW 19'

18"

3'N

3'S

302

3*N

A Bathymetric chart of the Romanche Trench area on the equator shows the newly found passage for
deep water as a series of meandering canyons and mountain passes through the Mid-Atlantic Ridge at
about 15° West. Contour intervals are 1000 meters. The black dots and numbers refer to hydrographic
• stations.

"These charts are published from preliminary data based on the Chain — 17 survey. Corrections are
being applied. The final charts will be published at a later date in the scientific press/'

I

This detailed chart of the Romanche Trench was obtained while the 'Chain' steamed some 4,600 miles

over an area of about 180 x 600 miles.

50'

with. These .observations were
extended down to within a few
meters of the bottom, scraping up
mud in our Nansen bottles on many
occasions. Then a series of stations
parallel to the Ridge on the Eastern
Basin side delineated quite closely
the area where the coolest water was
entering the Eastern Basin.

Tentatively, it looks as if the sill
depth lies very close to 3750 meters
and is in the region of about 15°
West on the Equator.

At one time I had hoped to launch
a Swallow-type buoy into this cool
water to measure the flow, but after
studying the station data, I feared it
would be useless. The cool water
entering the Eastern Basin appears
to hug the bottom so very closely
that unless one could determine the
depth at which the pinger drifted
within exceedingly narrow limits —
say considerably less than 100 meters

- one ran the risk either of having
the pinger run aground while the
ship "tracked" it futilely for days, or
else having the pinger float a little
too shallow, thus missing the cold
water entirely, a fact which the
observer could not readily ascertain.

Therefore, the major effort to
determine the saddle of the Ridge
consisted of many hundreds of miles
of sounding runs and twenty or so
carefully placed hydrographic sta-
tions. The analysis of the results will
take considerable time before our
success or lack of success is known.

Lighted buoy _

fastened to a parachute

drogue at a depth of 55 meters """**•

is towed toward the east in the Atlantic _

Equatorial undercurrent. The westerly surface

current adds to the turbulence behind the buoy.

A study of the Cromwellian
Atlantic current next occupied our
attention: First a broad survey run
from north to south along 18° 30'
West was made to acquaint us with
the situation, with shallow stations
each degree from every 30 meters
down to over 500 meters — 18
samples in all - were analyzed for
temperature, salinity and dissolved
oxygen content. Then a lowering to
500 meters with the Richardson cur-
rent meter was made with current
measurements at frequent intervals
on the way down and up. This pro-
gram worked out so well that a
second section was made at 13° 30'
west with sirhilar stations every
thirty miles from 3° 30' south to
3° 30' north. In the course of this
second section and on the basis of
the results as they were obtained, a
parachute drogue was lowered on
65 meters of polyethylene line to
study the core of the east flowing
sub-surface current at about 10
minutes North latitude.

Cham - 17

The drogue and lighted buoy were
launched and we watched delightedly
as it started to drift rapidly to the
east. Before we could get any mea-
sure of its speed, it was suddenly
and inexplicably sucked down out of
sight. A second effort met the same
fate. For a third attempt Charles
Parker improvised a more power-
fully buoyant float, and a drogue
launched at 2200 one evening was
followed until 1730 the next evening
at which time it was recovered. The
only slightly disappointing feature of
what was otherwise a magnificently
successful experiment came from the
fact that cloudy weather precluded
as many celestial fixes as we could
have hoped for. However, we feel
that the navigational control was
adequate to establish a good deal of
information about the current.

The buoy took off to the east
surging through the water and leav-
ing a wake like a moored buoy in the

New President
D

Woods Hole Channel with the tide
running. The ship followed closely
along side and repeated ship log
measurement showed the surface
buoy, dragged by a parachute at
about 55 meters in depth, to be
moving through the surface water at
a speed up to 2% knots. Our meager
celestial sights indicated that of this
2% knots, about % of a knot was due
to a westward flowing surface cur-
rent and 2 knots due to the eastward
flowing sub surface current.

This was written as the 'Chain'
approached Sierra Leone to pick up
more scientists for additional studies
on the third phase of the cruise. But
several of us are already laying plans
for a cruise we would like to make
sometime in the future when we
hope to measure the subsurface
current system all the way from the
coast of Africa to the coast of Brazil
— but in an air conditioned ship!!

'URING the annual meeting on August 11, 1961, Mr. Homer H. Ewing
of Wilmington, Delaware, was elected President of the Associates of the
Woods Hole Oceanographic Institution. He succeeded Mr. Noel B. McLean
of Stamford, Connecticut, who served as President since 1955 and was
elected Chairman of the Board of Trustees of the Institution on the
above date.

Mr. Ewing recently retired from the duPont Company and is widely
known in industrial circles having served as President of the National
Security Industrial Association and as Chairman of its Undersea Warfare
Panel. He has been a member of the Board of Trustees of the Woods Hole
Oceanographic Institution since 1959. We feel sure that the Associates will
welcome the leadership of Mr. Ewing and congratulate Mr. McLean upon
his election as Chairman of the Board of Trustees. We are most grateful
for Mr. McLean's many years of service to the Associates.

Chain - 17

Some Statistics

Major purpose: To study the Romanche Trench in the Mid-Atlantic Ridge.
Divided into three phases. Ports of call: Bermuda and Freetown, Sierra
Leone. Departed Woods Hole 1 February 1961. Returned May 16, 1961.

Total miles sailed: 16,630 of which
4,601 miles were devoted .to a thor-
ough bathymetric survey of the
Romanche Trench and its surround-
ings over an area of 180 x 600 miles.

Days at sea: 1st leg: 30 days, 12 hours, 17 minutes (more than any of our
ships ever spent at sea). The longest voyage by 'Atlantis' was 28 days.
2nd leg: 19 days, 20 hours, 11 minutes. 3rd leg: 24 days, 15 hours, 19 minutes.

Personnel: Scientific party: 3 ladies,
26 men (not all on board on each
phase). Chief scientists: Phase 1:

Dr. A. Voorhis, Phase 2 & 3: Mr.
Wm. G. Metcalf. Ship's Compliment:
29 officers and crew. Part-time par-
ticipants: several unidentified land-
birds, one of which stayed on or
around the ship for five days a
thousand miles from land.

18 crossings of the Equator between March 4th (day of ceremony) and

April 27th. Possibly only old whaleships or lurking warships ever crossed

the Equator so many times in such a short period.

Data: 1085 temperature observations
and an equal number of salinity
measurements, chiefly made on the
second and some on the third leg of
the cruise on 53 hydrographic sta-
tions. 1200 oxygen titrations, 900
total phosphate determinations, 800
insitu inorganic phosphates, and 450
samples frozen on which inorganic
phosphates, silicates, nitrates and
nitrites were run.

4 large volume water sample stations providing 33 water samples for
fission product studies on each station. 675 bathythermograph observa-
tions. 78 plankton tows. 24 mid-water trawls. 57 parachute drogue
observations. 2 big buoy drogue observations. 1 small buoy drogue observa-
tion. 20 scattering layer stations, totaling 30 hours and using some 350 Ibs.
of explosives. 13 lowerings of the velocimeter. 40 current shear studies.
8 piston coring tube lowerings. 17 Van Veen samples. 1 Pipe Dredge.

Routine observations: Continuous
bottom recording with the Precision
Graphic Recorder. Continuous ob-
servations of atmospheric and
oceanic CO2. In addition biological
observations were made of visible
marine life and of birds. Many
surface dipnet collections were made
day and night. A few hours also were
spent in chasing porpoises, blackfish
and sperm whales and recording
their sounds.

Equatorial Undercurrents

HE recent "discoveries" of strong, shallow Equatorial undercurrents in
the Pacific and in the Atlantic Ocean throw an amusing sidelight on
scientific research. At first we thought: "Ah, here is a fine triumph for
oceanography"! Two hitherto unknown major ocean currents comparable
in volume of flow to the Gulf Stream have been found by oceanographers
from the Scripps Institution of Oceanography and from the Woods Hole
Oceanographic Institution. This is a triumph for our science and could be
used to point out how much we still need to learn of our earth.

Now it turns out that evidence of these currents dates back some
75 years and that for some reason or other one had lost sight of the earlier
works on the subject. The German oceanographer Krummel reported in
a book published in 1911 that J. Y. Buchanan on the 'Buccaneer' measured
the Atlantic Equatorial Undercurrent at 55 meters moving south-east at
more than one knot underneath a weak westerly-flowing surface current.
Apparently the measurements were made while the ship was more or less
anchored by its cable recovering line, and there was some criticism of the
results because the line was dragging.

Puls (1895) observed in both oceans that when the south-east Trade
Winds on the Equator died out for a period of time, an easterly-flowing
current developed at the surface, and he suggested that it was constantly
present as an undercurrent, coming to the surface only during
extended calms.

Cromwell, Montgomery and Stroup described in 1954 the behavior of
long-line fishing gear in the Equatorial Pacific leading to their positive
identification of the subsurface easterly flow. Following Cromwell's
death, the suggestion was made that this current be called the Cromwell
Current.

On the IGY trans-Atlantic section along the Equator, made in
December 1958, the behavior of the wire on the hydrographic stations
convinced us of the presence of a swift shallow easterly undercurrent.
Shallow casts on the stations showed a much larger easterly angle than
did the deep casts where enough wire was below the current so that the
current drag forces were counterbalanced.

Neumann (1960) reviewed the earlier literature on the subject and
discussed the dynamic topography of the Equatorial region. He pointed
to the probability of there being an Atlantic Ocean version of the
Cromwell Current. Soon afterwards, Voigt (1960) reported on an anchor
station occupied by the 'Mikhail Lomonosov' on the Equator at 30° West
on May 1959. They found an easterly current of a knot and a half at 50
and 100 meters dropping to under a knot at 150 meters. This was during
a period of calm weather, and a surface current flowing east at a knot or
more was present.

On the recent cruise of the 'Chain' to the Romanche Trench, one of
the major objectives of the operation was the study of this interesting
feature.

We were most excited when the Atlantic Equatorial Undercurrent
was indeed found to exist and were amazed by its strength. Much work
needs to be done to delineate and to understand these rediscovered
currents, the actual driving mechanism is unknown for either current and
there are significant differences between the Pacific and the Atlantic
Equatorial undercurrents which are not yet understood.

10

Sound

Scattering

BY R. H. BACKUS

c

\^j HAIN' Cruise 17 was especially
interesting to me because it was the
first of several Atlantic crossings I
have made in which a wide band of
latitude was covered. Most of our
trans-Atlantic passages are pretty
much west to east or east to west.

My principal concern on this
voyage was the study of the variation
in sound-scattering over the track
between Africa and Woods Hole.
Sound scatterers in the sea are
mostly restricted to the upper few
hundred meters of the water column
and occur in strata (the so-called
"deep scattering layers"). The most
effective sound scatterers are be-
lieved to be small bathypelagic
fishes with swimbladders. The gas-
filled swimbladder is an effective
scattering agent as its acoustic
contrast is high compared with sea
water and the remainder of the
fish's body.

Sound-scattering may be studied
in several ways. The most effective
manner designed to date and the one
employed on this cruise, uses the
explosion of a small (one -half
pound) charge of TNT as the sound
source. The echoes from the scat-
terers are received by a hydrophone,
or underwater microphone, and are
stored by a magnetic tape recorder.
Ashore, the tape recordings made at
a number of stations along the ship's
track are analyzed to show the
intensity of sound-scattering as a
function of depth and sound fre-
quency.

"Over the side!" goes a half pound
charge of TNT.

DR. BACKUS is a marine biologist on
our staff. His interests are not only in
scattering layer studies but include
natural studies of sharks and whales and
studies of the sounds produced by
marine life.

Preliminary analyses of the data
from 'Chain' 17 show that the
intensity of sound-scattering is well
correlated with our other observa-
tions of the relative abundance of
life in the sea along the Africa to
Woods Hole track. In the region from
the equator north to the beginning
of trade wind zone and the Sargasso
Sea, sound-scattering is intense and
here we saw many birds, sharks,
porpoises, and whales and net hauls
for deep-sea fishes were good. On
entering the trade wind zone and
coming into the Sargasso Sea signs
of life at the sea surface became
fewer, net hauls were poorer, and
sound -scattering was much less
intense. Such a low level of "life"
was maintained until we crossed the
Gulf Stream and entered the rich
slope waters in the approaches to the
New England coast.

11

^••O^MI^H* •V^K^^^B^^h«H«M^^KV*MiHHMAM^M^Mr JWm.^^Ml^HMW B^MU^M^^ V^Ma ^^V^K^^K^KK^M^H^^^B'^B^^— ^H-

STARS and GRAVITY

A

new system of navigation, called GEON (Gyro Erected Optical Naviga-
tion System) was successfully tried out at sea during 'Chain' Cruise 17.

The system consists of a north-seeking gyrocompass rotor slaved to a
second horizontal rotor oriented east-west on its spinning axis. The combina-
tion provides the gravity vertical and the geographic north point and thus, the
local meridian plane. Disturbing responses to horizontal speeds and accelera-
tions are made quite small by coupling suitable sensors to the gimbals and
converting their signals into appropriate correcting torquess to precess
the rotors.

Celestial navigation can be practiced at any time of the day or night
when clear skies exist. Given the local vertical and north point to define the
local meridian plane, Greenwich Mean Time and the celestial coordinates of a
body, it is possible to fix the momentary latitude and longitude of a moving
ship to one minute of arc (1 nautical mile) from a single observation, and to
track its change of position with time by taking serial observations on a single
celestial body.

As a by-product, the apparatus also makes it possible to take 30-minute
time exposures of the sky with small cameras mounted on the gyro. The photo
above shows the Milky Way in the Crux-Argo region, photographed on
19 March 1961 while the 'Chain' was underway at 13 knots in lat. 00-10 South
and long. 18-44 West. Compensations for roll, pitch and yaw were provided
by the Sperry Mark 19 Meridian gyrocompass. Corrections for the ship's
motion in latitude and longitude as well as for the earth's rotation were
provided by hand guiding on Spica.

12

See: "Applications of the Gyropendulum",
by W. S. von Arx, The Seas, Ideas and
Observations; Interscience Press, N. Y. (in
press).

30-minute time
sky made while
el led at 13 knol
cross and the "co;
the left of center
top. Zeiss Biota
length, f.2

D. W. S. von Arx, assisted
by Lorraine Barbour, making
a gravity observation in the
box-sized laboratory observa-
tory mounted on the boat
deck of the 'Chain'. The
gravimeter employs a non- i
magnetic steel ball falling
slowly through silicone oil
of very high viscosity.

X

cr

z
o

exposure of the
the 'Chain' trav-
;. The southern
1 sack" appear to
North is at the
% 50 mm focal
on Tri-X.

Star observations for navigation could be made by day or
night with the aid of a small equatorially mounted
theodolite, fixed to the head of a meridian gyrocompass.

BY G. D. NICHOLLS X <•*

BOTTOM >'

SAMPLING

.UCH effort has been, and is
being, expended in studies of the
seas and oceans as they now exist.
Much more still remains to be done.
Yet it is not too early for speculation
on the development of the oceans,
how the waters came to acquire their
present complexities, how the basins
evolved. Speculation has its place
in science but it can never substitute
for investigation. The need for such
investigation is obvious. The oceans
as we know them are but a stage in
a continually changing sequence. To
understand them fully, even in their
present form, we must know some-
thing of the earlier pictures in this
kaleidoscope of time. History leaves
its imprint on the material world no
less than on the mental processes of

man; no scientist studying any part
of the planet Earth can neglect the
time factor.

Though the need is obvious the
methods to be used are less so. Geolo-
gists, in their studies of Earth's
development have long believed that
"the record of the past is written in
the rocks." For the oceanographer
the record of the past is written in
the sediments of the ocean floor. We
must learn to read that writing, to
interpret the meaning of what we
see and find in these sediments so
that, one day, we may understand
something of the nature and form of
the oceans in the long stretches of
time before man arrived to study
them.

14

Traditionally, geologists have at-
tempted deductions about earlier
conditions from the nature of fossils
found in deposits formed in those
remote times, or, more precisely,
from the character of fossil assem-
blages. Investigations of sub-surface
geology by means of boreholes, with
its restriction of the amount of
material available for study, stimu-
lated interest in micropalaeontology
— the study of micro-fossils. Over
the last decade or so the possibility
of pushing this line of approach to
its logical conclusion has been
explored, viz, — using the atoms
themselves, of which the rocks and
sediments are composed, as "fossils".
The relative proportions of the
chemical elements and their location
in different components of the sedi-
ment are influenced by the conditions
of sedimentation and the character
of the water in which the sediments
accumulate. Sufficient work has
already been completed to indicate
that this approach holds considerable
promise as a means of deducing con-
ditions in bodies of water on the
surface of the planet in remote times.
Some of the critical chemical ele-
ments in such studies are present in
sediments in only trace amount,
calling, for very careful analytical
techniques for their determination,
but the science of sedimentary geo-
chemistry is developing fast as more
and more of the analytical problems
are solved. To a considerable degree
micropalaeontology and sedimentary
geochemistry complement each other
and we may hope that the use of
both approaches in the study of deep
sea sediments will produce much
information relative to the develop-
ment of the oceans. These, then, are
our methods.

Dr. Vaughan T. Bowen early
recognized the significance of the
new geochemical approach to sedi-
mentation in oceanographic studies
and contacted the author of this
article during a visit of the latter to
various geological institutions in

U.S.A. in 1956-57. One outcome of
our discussions was the bottom
sampling program undertaken by
R.V. 'Chain' on the third leg of cruise
#17 from Freetown, Sierra Leone, to
Bermuda. Five sediment cores rang-
ing in length from 24 feet to 37.5 feet
were taken at pre-determined sta-
tions meeting the requirements of a
sedimentary geochemical investiga-
tion of the ocean floor. One of these
cores was raised from a depth of
7,610 metres in the Romanche Trench
and study of it should throw interest-
ing light on the origin of that
remarkable topographic feature.

Long hours

The requirements of a geochemical
investigation impose quite stringent
controls on the sampling of cores of
deep sea sediments. Great caution
must be exercised to avoid contam-
ination from any source. Further-
more, until we are more fully aware
of the possible extent of diffusion of
chemical elements, especially those
in trace amount, in the interstitial
waters of the sediments, the only
wise course is to extrude and sample
the cores as soon as possible after
collection. Aboard the 'Chain' extru-
sion from the core barrels and
sampling was initiated immediately
the cores came over the side. While
the sympathetic concern of the
'Chain's' company over long hours
spent at the extrusion table is
appreciated, it may be pointed out
here that no scientist, having at last
got the cores he wants on the
extrusion table, would willingly
yield the sampling knife to any
other. Thousands of miles and
months of waiting precede those
exciting moments when the sediment
cores begin to slide from their enclos-
ing barrels. The need for sleep is a
most exasperating natural weakness
of the human frame at such times.
Fortunately, on each occasion the
core was 'cleared' before 'Chain'
reached the next station and progress
was never held up by the sampling
stipulations of our geochemical
program.

15

Exciting discovery

Successful and satisfactory as our
coring program was, the most excit-
ing part of the bottom sampling
work was not part of the planned
program at all. On May 6th an
attempt was made to obtain a sedi-
ment core from the eastern flank of
the Mid-Atlantic Ridge at latitude
19°23' N. As is well known, the
bottom topography on the flank of
the ridge is highly irregular with
many topographic high (hills) sep-
arated by lows (depressions). The
corer was lowered over a depression
where the water depth was approxi-
mately 2,650 fathoms but even as the
corer went down 'Chain' drifted over
a hill and by the time the corer was
nearing the sea floor the depth was
only 2,420 fathoms. The danger of
the corer being buckled by contact
with a solid floor was considered but,
after some deliberation, it was
decided to continue with the opera-
tion. Let it be admitted now that
secret daydreams were being enter-
tained that we might, we just might,
get a sample of the solid rock from
beneath the sediments in such a
location. Dame Fortune had smiled
so sweetly hitherto that she might
even go that far. The time required
for raising the corer to the surface
seemed interminable. Only those
who endured that waiting can fully
appreciate the excitement as the
main corer was examined — or the
acute and stabbing disappointment
at finding it empty. Some minutes of
disconsolation passed before the pilot
corer was checked. As the liner slid
out of the pilot tube all disappoint-
ment evaporated in a burst of elation
for the liner held red clay and in
addition a fragment of the solid rock
from beneath the sediment of the
ocean floor - - a freshly broken frag-
ment of a dark natural glass. Subse-
qent examination of the piston of the
main corer showed red clay stuck on
its end and, embedded in the clay,
shards of the same glass. Many
boulders have been dredged from
the floor of the Atlantic over the

A volcanic boulder, about one foot long, was
brought up by hauling a pipe dredge up the
western slope of the central valley on the Mid-
Atlantic Ridge. The haul was made between
depths of 1910 fathoms to 1542 fathoms.

A section of the boulder shows a white rim
consisting of loosely aggregated modern foramini-
fera coated by manganese where the boulder
was exposed.

16

Bottom Sampling —

years which are almost certainly
locally derived. But they cannot be
proved to be representative of the
sub-sediment surface in the same
way as can the fragment broken and
recovered from that surface on the
afternoon of May 6th. At last specu-
lation can give place to investigation
— at last we have a sample indis-
putably from the sub-sediment
surface. I do not consider it too
extravagant a claim that this cruise
would have been justified if this
specimen alone had been won from
the waters of the Atlantic. Yet to fill
our cup of success to the brim an
hour or so later we raised a 30 foot
core of sediment from an adjoining
area.

So it is that we look back on a
bottom sampling program successful
beyond all our hopes. Though much
work has to be done before our
samples yield their secrets to us, the
program for geochemical investiga-
tion of deep sea sediments of the
equatorial Atlantic has got off to a
most auspicious start.

Ending on a personal note I wish to
thank all those who helped to make
this cruise so successful. Richard C.
Leahy, Peter L. Sachs and George L.
Erlanger laboured long and willingly.
Dr. Bowen's never-flagging faith and
encouragement were a constant
source of inspiration. To these and
many others I tender my sincere
thanks.

DR. NICHOLLS, is Associate in Geo-
chemistry on our staff and lecturer at
the Department of Geology of the Uni-
versity of Manchester, England.

ARENDS

At a depth of about 25,000 feet a deepsea
holothurian was photographed by an
Edgerton camera in the Romanche Trench.
Recently our colleagues at the Lamont
Geological Observatory took a photo of a
whole group of Holothurians in the Chilean
Trench. Both photos are the deepest known
views of these bottom dwellers. The animal
shown is about 6 inches long and is closest
to Penagione incerta Theel, known to grow
to about three inches.

A manganese covered piece of

ancient Foraminifera cemented

together by opaline cilica.

BRAY

17

Foraminifera

BY R. CIFELLI

The most common sea shells are but little known
to most people, yet provide a history of the earth.

18

.HE Foraminifera are inconspicu-
ous because of their small size —
mostly about the size of a sand grain,
though some fossil giants were
several inches long — and are little
known to most people. Yet these
unicellular shelled animals are found
almost everywhere in our Recent
seas and are of great geologic impor-
tance. Foraminifera are, in fact,
among the most common of shelled
animals. They are widely distributed
in marine rocks throughout the
geologic column from the Lower
Paleozoic to the Recent and probably
no other group of organisms has had
such a long, continuous history pre-
served. The Foraminifera are widely
used by geologists for the correlation
of rock strata and for the interpre-
tation of ancient environments.

Foraminifera are found in all
marine environments from brackish
marshes to abyssal depths. Most
species are benthonic and crawl on
the sediments of the sea bottom or
are attached to sea weed and other
objects. A few species are pelagic
and live floating in the water above
the bottom as part of the planktonic
fauna. The remains of the animals,
after death, sink to the sea bottom
where they accumulate in enormous
numbers. In the shoaler parts of the
deep sea, where little sediment is
received from land, the shells of
pelagic Foraminifera form sticky,
shelly deposits called Globigerina
oozes, because of the predominant
occurrence of Globigerina and other
pelagic species. At great depths,
below about 15,000 feet, Foraminifera
do not accumulate because the shells
are dissolved in the cold, calcium
poor waters.

*Published by permission of the Secretary,
Smithsonian Institution

The Foraminifera are valuable in
the study of deep sea sediments, and
are used as indicators of geologic
ages and past marine environments.
Sediments as old as Cretaceous have
been penetrated by cores and recog-
nized by the occurrences of extinct
species of pelagic Foraminifera. Most
cores, however, do not penetrate
below the Pleistocene, because of the
short length of the coring devices.

The Foraminiferal material col-
lected from the Romanche Trench
cruise is extremely valuable because
it comes from a remote, not easily
accessable part of the world. Plank-
ton samples were collected along the
entire traverse from Bermuda to the
equator, thus covering an unusually
large range of latitude and represent-
ing a unique opportunity to study
the distribution of living forams
during one cruise.

The five cores collected in the
Equatorial Atlantic and southern
part of the North Atlantic contained
layers rich in Foraminifera. One of
the cores came from the bottom of
the Romanche Trench, at a depth of
over 24,000 feet. There are no Fora-
minifera at the top of the core, as
would be expected, since at that
great depth the shells are dissolved
before they reach the bottom. How-
ever, at some depth below the top of
the core there is a thick layer of
almost pure Globigerina ooze. A
similar appearing ooze occurs on the
surface of the bottom on the slope of
the trench at a much shallower
depth. It is too soon to speculate on
the origin of the ooze in the core, but
its presence there has an important
bearing on the history and past
conditions of the trench.

Carbon Dioxide

BY R. G. LEAHY

OINCE the middle of the 19th
century the normal cycle of carbon
dioxide in the ocean and the atmos-
phere has been affected, by the in-
creased burning of fossil fuels.*
It has long been realized that this
action could result in an increase in
the amount of CO2 in the atmos-
phere and the oceans; and since such
an increase would markedly affect
the earth's weather, this process has
been the subject of considerable re-
search and speculation.

The cruise of the 'Chain' to the
Romanche Trench offered a valuable
opportunity to study the exchange of
carbon dioxide across the sea surface,
as the ship's track covered a wide
range of latitude and hence en-
countered a great diversity of
oceanographic conditions. Since the
level of carbon dioxide is dependent,
among other things, upon tempera-
ture, pressure and biological activity
it had been predicted that there
should be areas in the ocean where
carbon dioxide is taken up by the sea
and other areas where the sea is
releasing carbon dioxide to the
atmosphere.

To study this problem an infrared
analyzer was set up on board the
ship and arranged to monitor the
atmospheric and surface sea water
CO2 levels. In addition, measure-
ments were made of the acidity of
surface sea water and of various
meteorological parameters. In gen-
eral it was found that the carbon
dioxide levels in the ocean increased
with increasing surface water temp-
erature, a result that would be
expected on the basis of the solu-
bility of CO2 in sea water. Com-
monly, the levels recorded at higher

*See: "Sun, Sea and Air", Oceanus, Vol. V,
nos. 3 & 4.

latitudes indicated that the water
was undersaturated with respect to
the atmosphere while in the tropics
the reverse was the case. This
tendency can be seen on the diagram
which illustrates the values recorded
along the ship's track between
Bermuda and the Romanche trench.
One particularly interesting aspect
of this section was the indication of
supersaturated water in an area that
correlates with the position of the
Atlantic Equatorial undercurrent.
Although not presently understood,
these CO2 levels are undoubtedly
related to the mechanism of the
formation and maintenance of the
undercurrent.

The values recorded for trade wind
air are similar to those recorded dur-
ing previous studies in the western
Equatorial Atlantic. The relative
constancy of values measured under
similar meteorological conditions
was also in agreement with earlier
studies, but under certain circum-
stances parallel daily variations of
the surface sea water and atmos-
pheric values were noted but have
not yet been satisfactorily explained.
These diurnal variations suggest that
the transfer of CO2 across the sea
surface can take place quite rapidly.

On the other hand, an analysis of
the records showed evident differ-
ences in the atmospheric and surface
sea water CO2 levels which is indica-
tive of a rather slow exchange rate.
This slow rate is in accordance with
previous investigations carried out
at the Institution and precludes the
possibility of the tropical ocean being
a sink and an effective reservoir for
atmospheric carbon dioxide.

19

IPS

BY V. T. BOWEN

Studies of radioactive elements in the sea indicate that bomb test
debris returns at a much higher rate on the ocean than on land.

A

major activity within the Insti-
tution's geochemistry program for
some years now, has been the
analysis of the changing distribution
of long-lived radioisotopes from fall-
out in the Atlantic Ocean. These
isotopes in general were not meas-
urably present in sea water before
mid-1954, and measurable amounts
have been delivered to the Atlantic
Ocean only by bomb-test fallout
precipitation onto the sea surface,
hence study of their distributions in
sea water, both horizontally and
vertically, permits us to see how
rapidly various chemical elements
move from the upper layers toward
their final end in the bottom sedi-
ments. By relating this information
to other factors, we can also tell
something about the mechanisms
responsible for these movements.
And in cases of particular elements
which can be shown to move only as
the water itself moves, we can see
how rapidly water masses inter-
change across their boundaries, and
how rapidly they homogenize within
these boundaries. In addition, once
we have a clear picture of the
distribution, both horizontal and
vertical, in an ocean area, this can be
used, by comparison with data from
land and island stations, to study the
total fallout delivery in various
periods of time. From this we can
compare either the rates of precipi-
tation in the meteorological sense, or
the mechanics of precipitation; un-
fortunately this data does not allow
us to argue simultaneously both of
these meteorological questions.

It is one of the exciting things
about oceanography that so often
this experience arises: a series of
measurements undertaken for a
specific and relatively narrow pur-
pose proves to be giving information
of very broad interest in several
related areas of study. The spreading
impact of these fallout studies has
been a satisfactory example.

Sampling Problems

Before going into a discussion of
results or of cruise planning, we
should point out that although the
amounts of radioactivity involved in
these studies are measurable, they
are only barely so. Even though we
use highly refined counting proced-
ures, modeled to a great extent on
those used for carbon-14 dating, we
still require 15-gallon samples of
sea water, and would use larger
samples if not limited by the cargo
capacity of our research vessels.
Because the certainty of accuracy
provided by analyses of duplicate
samples is more important than the
improvement in precision produced
by a two-fold increase in counting
rate, we collect 36.5 gallon samples
from which we bring back two 15
gallon duplicates.

Catching such samples of sea water
from all depths is a time consuming
and laborious task at best, and it has
taken some years and a lot of inge-
nuity both from the Institution's
instrument shop, and from the expert
gear handlers at sea, to achieve our
best. The gadget used was a product

20

of the ideas and experience of R. H.
Bodman and L. V. Slabaugh of the
Shop, reacting with the plaintive
expressions and mechanical non-
dexterity of the man with the
problem. It has recently been
described for journal publication.
These samplers first were used in
1958 on 'Crawford' 22, the equatorial
crossings during the International
Geophysical Year from which the
present Romanche cruise developed.
Enough sample is brought in for a
variety of other analyses as well as
for the fission product studies. And
since the samplers are lined through-
out with a plastic like Teflon
(Kel-F), and use polyethylene valves,
the water caught in them is useful
for most biological, physical and
chemical purposes.

Our idea in planning on large
volume sampling has always been
that we should concentrate on a
device suitable for use on the usual
hydrographic wire (3/16 or 5/32 inch
diameter). This has implied restric-
tion to devices such as the present
one, which provide only one sample
per lowering. Furthermore, the effort
to make a device which can be
handled on a rolling deck with great-
est ease and least hazard, led to the
samplers being light in relation to
their size. This in turn means that
if they are lowered beyond a definite
maximum speed, the wire sinks
faster than the sampler and a tangle
results. This speed for 3/16 wire is
about 2700 meters an hour, and
defines the limit of the rate at which
samplers can be completed. A whole
station of nine samples from surface
to 4000 meters, for instance, requires
close to ten hours hove to. In addi-
tion, a complete hydro station is
needed, taken when possible just
before the large sample station.

Previous Cruises

Our fallout analyses have so far
dealt largely with strontium-90,
cerium-144 and promethium-147; we
have also made a small number of
analyses of cesium-137. Of these
isotopes, we are inclined to believe

that strontium and cesium move in
the ocean only as solutes; that is,
the overwhelmingly major amount
of each of these exists dissolved in
the water, and significant movement
either horizontally or vertically
requires comparable movement of
the mass of water. On the other
hand, cerium and promethium seem
to be largely associated with the
small particles of solid matter in
ocean water; these have rates of
vertical movement different from
those of the water masses in which
they are suspended.

In the cases of strontium and
cesium, our view, summarized above,
is not unanimously held. Under
special circumstances both of these
elements are strongly concentrated
by living things, and consequently
the possibility exists that the ele-
ments, and necessarily the isotopes
of concern to us, are moved verti-
cally in the water column in the
bodies of organisms. We think that
in the open ocean this is not occur-
ring for these two isotopes to a
significant extent. Our arguments
are complicated, but may be sum-
marized as follows: Both isotopes are
present in fallout, whether dry or
rain, in wholly soluble form. The
strontium-90 must then be assumed,
on hitting the sea surface to mix
isotopically with the rather large
amount of stable (naturally occur-
ring) strontium in surface sea
water, and chemically with the much
larger amount of stable calcium.
Once this mixing has taken place no
organism can remove strontium-90
from the water without simultan-
eously removing stable strontium in
proportion, and most organisms must
also remove stable calcium in the
same or even higher proportion. In
the case of strontium-90 we are talk-
ing about vertical transfer across the
100 meter level of 20 to 50 per cent
per year, a removal of the stable
strontium or calcium which would
be readily seen in chemical analyses
as a depletion fn surface waters and
an enrichment at deeper levels. In
fact, however, no such effects are

21

Isotopes —

seen in the observed value of calcium
or strontium. This would appear in
case of isotope removal by transfer
downward of an amount of "labeled"
water, which is replaced by water of
closely similar chemical but different
isotopic composition.

Although the stable cesium con-
centration in sea water is much less
than the strontium concentration,
there is enough combined with the
large amount of potassium (which
organisms generally cannot distin-
guish from cesium), so that marine
creatures do not often take up the
cesium from as much water as ten
times their own volume. Such low
concentration factors are not effec-
tive in moving significant amounts of
either radioisotope or element.
Another line of argument stems from
the fact that the ratio of strontium-90
to cesium-137 in surface water does
not vary widely, and is close to the
ratios both in rain and in fission
production. Since organisms do not
take up these two radioisotopes, or
their elements, in one to one ratio, it
is most unlikely that mass transport
by living things could result in an
unchanged ratio in the water, or in
a uniform ratio at all.

Strontium-90

Measurable amounts of strontium-90
were not added to the Atlantic
Ocean until the bomb tests of
spring, 1954; we may take July 1,
1954 as our starting date. By spring
and summer of 1957, however,
samples from 300 to 500 meters deep
showed strontium-90 with 30 to 50%
of the surface concentration; smaller
but measurable amounts were seen
in some samples from 1000 to 1200
meters. In July of 1958, stations
taken in the Sargasso Sea again
showed this pattern; from 300 almost
to 700 meters about half the concen-
tration found in the upper 100
meters, and at 1000 meters almost
half the 700 meter concentration. If
we assume that no significant
strontium-90 was yet to be found
below 1000 meters - - an assumption
almost certainly unwarranted —

integration of these figures still
shows more than four times as much
strontium-90 in the water column
below 100 meters as above that level.
This generally distributed downward
motion has taken place at a higher
rate and to a greater depth than had
been thought likely either from con-
ventional hydrographic studies, or
from other estimations of naturally
occurring radioisotopes like carbon-14
or radium. The repeated demon-
stration that these movements do
take place has already convinced
some carbon-14 students, and wider
acceptance is being steadily achieved,
indicated among other things by inter-
est from other laboratories in making
measurements of strontium-90.

Another, and more puzzling fact
came from these stations: that the
ocean water column contains more
strontium-90 per unit area, than does
the land surface at comparable lati-
tudes; about three times as much in
fact. After a very careful reexam-
ination of our now more extensive
data, we have concluded this is real:
that bomb test debris returns to
earth's surface at a much higher rate
on the ocean than on land. This has
been partly confirmed by Weather
Bureau studies showing higher fall-
out per unit area at coastal than at
inland stations, and still higher
values for islands, though in each
case well below our estimates for the
surface of the open ocean. No idea
yet exists for the mechanism produc-
ing this high sea surface fallout; it
does fit recent ideas that fallout
remains in the stratosphere for much
shorter times than was previously
estimated.

Cerium-144 and Promethium-147

When we began this study, these
isotopes were expected to be treated
in the oceans exactly alike, each
associating with the surfaces of
particles and sinking through the
water column at the velocity of these
sinking particles. This has not proved
quite so simple: although both
cerium and promethium separate
from strontium under conditions

22

Isotopes —

which convince us they do sink in
association with particles, they also
separate from each other, cerium
tending to stay longer in the upper
layers. Somewhat involved argu-
ments from the chemistry of cerium
at very high dilutions under condi-
tions found in sea-water, lead us to
conclude that promethium associates
largely with inorganic particles
sinking at rates much faster than
100 meters a month; cerium, we
think, associates with particles of
high organic content; two popula-
tions of cerium labelled particles are
in evidence in our stations, one sink-
ing at about 100 meters a month, the
other at no more than half that rate.

It seems thus that from changes in
the ratio of promethium to strontium
radioactivity we may draw conclu-
sions about the total surface area of
particles sinking through a water
mass in a given time, and from
changes in the ratios of cerium to
strontium and to promethium radio-
activities, conclusions about the
organic vs. inorganic nature of these
particles. Unfortunately, little par-
allel data exists to be used in testing
the conclusions resulting from this
hypothesis.

The Romanche Trench

As mentioned above, 'Chain' 17
was really conceived during the Inter-
national Geophysical Year cruise of
R.V. 'Crawford' across the equator
from east to west. On this cruise
several of us first saw the depth
profile of the Romanche Trench, first
saw the current system along the
equator, flowing at surface from east
to west, and at only about 75 meters
down much more strongly from west
to east, and left with many more
questions than, it has proved, could
be answered even by one more
cruise to the same area. Two large
volume stations were made on the
equator, one a 9° 41' West and one at
33° 40' west. Thus, this first time we
neatly missed the Trench. The fis-
sion product distribution in the two
stations is complicated, and not yet
fully analyzed. One interesting and

\

V

Isotopes —

wholly unexpected point did, how-
ever, appear: rather than the, ex-
pected strong horizontal homogeneity
induced by the current systems, we
found vertical homogeneity; at both
stations down to below 300 meters
the surface value for strontium-90
was found, but this value at 9° 41'
west was just half that found at
33° 40' west. This seems impossible
to reconcile with the picture which
one ordinarily draws of the effect of
two rapid currents flowing in op-
posite directions. It is further com-
plicated by the finding that surface
values about 40° west are the same
at 24° south, at the equator and at 4°
and 8° north, whereas that at 9° 41'
west on the equator is very close to,
though slightly lower than that at
24° south, 7° east.

It was primarily to elucidate this
set of observations that the large-
volume sampling of 'Chain' 17 was
originally planned. Unfortunately,
problems of ship scheduling while
on the equator forced us to reduce
the number of stations made there
to just one, in the Romanche Trench.
Analyses of these samples will sub-
stantially confirm or question the
results of 'Crawford' 22, but will not
give enough information to improve
our picture of what mechanisms may
be producing the observed patterns.
In addition to the samples taken at
depths down to about 2500 meters,
from which we expect to see fission
product distribution, samples were
taken at 5000 and at 7100 meters, in
the cold water mass below the
Trench's sill, to be analyzed for
carbon-14. It is hoped that these
may yield data which can help tell
the time of the last intrusion into the
Trench of Antarctic Bottom Water
from the western basin, as well as
telling something about rates of
vertical movement in the Trench's
isolated, very homogeneous mass of
deep water.

The curtailment of our work on
the equator had been decided on the
basis of misinformation. This per-
mitted us to add some stations on the

DR. BOWEN is a Geochemist on our
staff. He also is a lecturer in Zoology
at Yale University.

run returning to Woods Hole. Of
these, two were in the eastern
Atlantic basin, one at 5° 15' north,
23.° 30' west was planned to coincide
with a region of divergence, or up-
welling, inferred by Defant, and indi-
cated by our profile of CO2 concentra-
tions made on the run out. The second,
at 11° 2' north, 29° 38' west, was plan-
ned to give an uncomplicated — if
such is possible - - view of conditions
in the Cape Verde Basin, to compare
with our stations at various points
in the western basin. Here also deep
samples, at 4000 and 5400 meters,
were taken for carbon-14 measure-
ments. In addition to these, several
surface samples taken for fission
products and carbon-14, will indicate
the agreement in respect to north-
south uniformity between east and
western basins. Finally a station
from surface to 1500 meters was
made in the southeast quadrant of
the Sargasso Sea, at 29° 15' north,
57° 31' west, chiefly for comparison
with our other stations from near
Bermuda, and from the northwest
quadrant.

All of the stations were excep-
tionally successful. This was due
partly to the fine weather, extreme
steadiness of 'Chain' and the high
efficiency of our gear and its hand-
ling aboard. In addition, the availa-
bility of the salinometer , now able
to return measurements within 15 to
20 minutes of obtaining the samples,
enabled us to identify immediately
the small number of malfunctions
(three in all) and repeat these
lowerings until good samples were
obtained.

Now we face a tantalizing wait:
from the start of sample processing,
begun for these 'Chain' 17 samples in
mid-August, about three months is
required before the strontium-90
analyses for the first samples are
complete. From then on data rolls
in at the rate of about six samples
each two weeks, if nothing goes
wrong. So we may well know the
results of the first station, in the
Trench, by early January, 1962.

24

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im

Contents

CHAIN — 17 TO THE ROMANCHE TRENCH

by W. G. Metcalf

EQUATORIAL UNDERCURRENTS

HD SCATTERING

BOTTOM SAMPLING

FORAM1NIFERA

CARBON DIOXIDE

by K. H. Backus

by G. D. Nicholls

by R. Cifelli

by K. G. Leahy

RADIOACTIVE ISOTOPE STUDIES

by V. 7. Bowen

SOME STATISTICS ON CHAIN — 17
STARS AND GRAVITY

Published by

WOODS HOLE OCEANOGRAPHIC INSTITUTION

WOODS HOLE, MASSACHUSETTS