Andreas B Rechnitzer.

Summary of the bathyscaph Trieste research program results : (1958-1960) online

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toward the background. However, no ripple marks or
scouring are evident. The two white crescents to the
left and right of photograph center are photoprocessing
faults. Dive No. 60.


Figure 7. The sea floor at 4900 feet on the west slope of
Guam was approximately 50 per cent exposed basement
rock with a thin mantle of sediment. The bedrock was
finely sculptured by erosion and dissolution of the softer
portions. A partially disintegrated palm frond (?) appears
in the lower third of the figure. Dive No. 60, (35- mm
electronic flash photograph)


Figure 8, A living single ship coral is found attached to
an unidentified substrate that is either an eroded piece of
sheet steel or exposed crustal bedrock. Sprinkled about
on the surface of the off-white sediment are small black
pebbles. At the lower center a heavy concentration of the
pebbles surrounds a depression of biological origin. Dive
No. 60.



Man's first direct viewing of the sea floor at 18, 150
feet was achieved on this dive, which brought the manned
deep- diving record back to the U. S. Upon landing, the
bottom was noted to be uniformly level, but pock-marked
with numerous white circular areas on a tawny substrate
(fig. 9). Closer examination revealed that biological
activity was responsible for these marks. The lighter sub-
surface sediment had obviously been brought to the surface
by burrowing animals. The sediment had subsequently
spread circumferentially about the penetration without
creating a mound. The bearing strength of the sea floor
was adequate to sustain the weight of the bathyscaph satis-
factorily. Maximum penetration was estimated to be no
more than 3 inches.

Figure 9 illustrates the numerous particles that were
present in the water immediately above the bottom. Bio-
logical entities and suspended particles above the sea floor
were conspicuous and a definite turbid condition existed.
The brownish tinge of the sea floor was thought to be caused
by the settling of the inanimate materials and organic sub-
stances present in the water mass directly above the bottom.

The sea floor downgrade slope was evident and esti-
mated to be about 1 degree. Upon leaving the sea floor,
the observers noted a vertical drop of 4 to 5 feet that inter-
rupted the gentle slope to form a "berm" running perpen-
dicular to the downslope gradient. Beyond this drop, the
sea floor appeared to have approximately the same depres-
sion angle. The upper discontinuity of the break in the
slope clearly revealed an exposed rock outcrop. Maximum
exposure of rock was 6 inches.

Evidence of ripple marks or scouring formations was
absent. The funnel-shaped depressions and/or volcano-
shaped mounds found at shallower depths and at all loca-
tions where bathyscaph operations had been previously
conducted were absent. Water current was negligible and
apparently had been in recent time insufficient to produce
ripple marks or contribute significantly to the alteration
of the microrelief. A few pebbles, about 0. 5 inch in
diameter, similar to those seen at 4900 feet, were scattered
irregularly throughout the area.

Upon leaving the bottom, it was possible to see that the
sphere had been supported during the bottoming by a ridge
of exposed rock 8 to 10 feet long.


Figure 9. The sea floor at 18, 150 feet reveals evidence
of biological activity, such as the whitish sediment
brought to the surface by burrowing animals. The "pock-
marked" light-brown sea floor was noted to slope down-
ward slightly to the left. The heavy concentration of
suspended matter near the bottom can be noted in the
figure. Dive No. 61.



Upon approaching the bottom, the fathometer readings
were questionable and, in an attempt to make a "soft land-
ing, " too much shot was dumped. Consequently the sea
floor at 22, 540 feet was sighted only briefly. The dive
yielded a new depth record and a test of the craft and its


The ultimate in depths- -the Challenger Deep- -was
found by explosive echo- ranging to have a flat- surfaced
full plane approximately 0. 5 mile wide and 3 miles long.
The long axis of the plane was parallel to the Marianas
Trench axis. The geographical location of its center was
determined by Loran sea fixes to be 11° 18. 5 'N latitude,
and 142° 15. 5'E longitude.

Upon landing, sediment was brought into suspension
where it remained for the duration of the 2 0- minute stay.
The sea floor was remarkably white and of extremely fine
material. It was uniformly flat and there was no evidence
of burrowing animals. Water current was virtually nil.
Microrelief was observed to be minimal. However, only
the area immediately adjacent to the touch-down point was

Near the bottom, a jellyfish approximately 3 inches
in diameter was observed pulsating 6 to 8 feet from the
sea floor. Just prior to landing on the bottom a red shrimp
swam through the cone of light.

At the bottom, Piccard reported observing a flat fish
looking like a sole, " Since flat fish are vertebrates and
teleosts, this demonstrates the capability of high forms
of life to exist at the greatest depths. Apparently a satis-
factory amount of oxygen and food replenishment exists
even there.

The previous record depths for fish were about 7000
meters, where they have been trawled by both the Danish
Galathea Expedition and by the Soviets from the Vityaz.
It is known that certain proteins coagulate at pressures
considerably less than those of the deep trenches- -for
example, a sea urchin egg will coagulate. Hence these
great depths might have been entirely without higher forms
of life for such barochemical reasons.


The TRIESTE depth was determined to be 35, 800 feet
following calibration tests of the Bourdon tube- type hydrau-
lic pressure gauges by the Eastern Standards Laboratories,
U. S. Naval Weapons Plant, Washington 2 5, D. C. Addi-
tional calculations of the depth attained were made and
offered to the author by Dr. John A. Knauss, Scripps Insti-
tution of Oceanography, Dr. John Lyman, National Science
Foundation, and Dr. Ernest R. Anderson of the Navy
Electronics Laboratory. These calculated values varied
from 34, 931 to 35, 805 feet depending upon the calibration
data used. The "best value" for the depth may be a few
hundred feet less than the figure 35, 800 used throughout
this report. Further investigation of the temperature
corrections to the pressure gauges may resolve the differ-


Dive No. 76 was made primarily to acquire sound-
velocity measurements. The ultimate depth reached for
these measurements was 18, 900 feet. The bottom was
obviously bedrock covered by only a thin mantle of whitish
sediment (fig. 10). The greater portion of the exposed
black bedrock was clearly rounded and appeared encrusted,
as if by accretion. Some individual small rocks, also
rounded and no more than 2 to 3 inches in diameter were
strewn about the sediment cover. The sea floor beneath
the mantle of sediments appeared to be a solidified mater-
ial with long ridges of outcroppings. The ridges formed
at the boundary where a minor drop in the downslope pro-
file existed.

The bedrock was exposed for long sections at this
nominal break in the slope. The slope gradient was esti-
mated to be 2 to 3 degrees. From a viewing vantage point
60 feet from the bottom, a distinct ridge of exposed rock
extended for more than 100 feet; it apparently ran parallel
to the axis of the trench. Isolated clumps of rocks were
for the most part flat, about 1 foot in diameter. They
protruded out of the bottom about 3 inches. Smaller frag-
ments, about 0. 2 5 inch thick and only 2 to 3 inches in
diameter were also distributed at random on the sea floor.

A few worm tubes protruded out of the sediment.
These tubes were approximately 0. 2 5 inch in diameter and
2 inches high. Within the thin sediment mantle, several
conical hummocks of sediment with a distinct aperture in


Figure 10. Photograph of the sea floor. Dive No. 76.


the center were noted, but there was no evidence of a bio-
logical inhabitant.

Upon landing, sediment was elevated into suspension
by the displaced water. The majority of the heavy material
remained in a suspended state only a matter of seconds and
then settled. The remaining material offered an index to
the prevailing water current velocity. The current was
measured visually to be less than 1 cm per second moving
parallel to the ridges of exposed bedrock. The water
immediately above the sea floor was clear and virtually
devoid of marine life and suspended particles.

A coil of material that had formed a 6- foot double S
was noted on the bottom. It was apparently a piece of

Visual observations of the sea floor at this location
were comparable to those made at 18, 150 feet (Dive No.
61). A definite sea floor slope of about 1 degree with
discontinuities involving abrupt breaks in the slope expos-
ing bedrock were present. Bedrock covered with a thin
mantle of whitish sediment was noted in both dives. The
mantle gave all appearances of being relatively thin.
Bearing strength, however, was again adequate to sustain
the weight of the bathyscaph and only a modest penetration
of the sphere was experienced.


The sea floor at 8530 feet revealed coarse sediment
cover of at least several inches. Here well- developed
ripple marks were observed. The average crest-to-
crest distance of all the ripple marks was estimated to
be 18 inches with an amplitude of 0. 75 to 1 inch (from
motion picture footage and fig. 11). Water current at
that time was 0. 7 cm per second. It appeared that the
water current flow rate, which was not oscillatory, would
be too slow to form such ripple marks, which were con-
tinuous and parallel. They showed no signs of cross-
rippling and were well formed, as though of recent origin.
No thin layer of dark material was present on the surface.
Some dark pebble- like particles on the bottom were
scattered at random about 2 to 3 inches apart. The par-
ticle size was only slightly larger than the ballast (i. e. ,
estimated to be 4 to 5 mm in maximum width).


Figure 11,

Photograph of the sea floor, showing bottom


Sediments brought into suspension were observed to
drift rapidly past the bathyscaph port. Water particle
movenaent through the illuminated area was at the rate of
0. 7 cm /sec. Water flow was perpendicular to the long
axis of the ripple marks. An attempt to obtain sediment
samples for correlation of water current velocity and the
physical dimensions of the ripples was thwarted by the
accidental loss of the sampler. There was no evidence
of burrowing or benthic organisms. Some pelagic inverte-
brates were seen in the water immediately above the sea
floor. Suspended inanimate particles were also present,
but in such quantities that visibility was not seriously


While this dive was made about sixty miles from Dive
No. 75, the materials making up the sea floor sediments at
this location appeared to be the same as in Dive No. 75.
However, ripple marks here were definitely crossed and
deteriorating, A thin mantle of dark substance had settled
on the bottom, occluding the clean white sediment observed
on Dive No. 75. The bearing strength of the material was
comparable to that of the previous sea- floor sediment
encountered. Biological life was limited to one starfish
and possibly a few tube- dwelling worms.

An artifact of man that caused great concern was an
unexploded 5- inch projectile that was located directly in
the circle of light provided by the bow lamp. Ironically,
a beer can was leaning against the base of the projectile.
Both objects were supported high on the surface of the sea-
floor sediment. There was no evidence of scour or settling
of these two artifacts (fig. 12). Water current flow here
was very slow and seemed to vary in direction. Poor
illumination vitiated any attempt to determine the precise
velocity of the current.


Figure 12. Photograph of the sea floor, showing bottom
ripples and artifacts (projectile and beer can). Dive
No. 78.



Sound-Speed Measurements

The primary purpose of the scientific program usin|
the TRIESTE during Project NEKTON II was to obtain
sound- speed measurements in situ. Table 1 gives some
of the data obtained.








Sound Spe

No. 1

3ed Meter

No. 2




13. 5

26. 92

34. 79

1540. 78

1540. 78



13. 5

25. 83

35. 01

1538. 86

1538. 87



32. 5


34. 08

1488. 7



13. 5

13. 77



1507. 75



12. 7

4. 15

34. 67

1485. 60




32. 5

3. 38

34. 53





3. 54

34. 50

1485. 00

1484. 86




1. 77







1. 75


1499. 67

1495. 93


2 598*


1. 72*













1. 44


1554. 68

*30 minutes later.


In general, the measured values of sound speed at
great depths were found to be less than those computed.
Measurements for depths greater than 8000 meters would
be very valuable to obtain or verify the depth dependence
of sound speed.

Reference 1 (see list of references at end of report)
presents a detailed discussion of sound- speed measure-
ments made from the TRIESTE during NEKTON E. Earlier
experiments using the bathyscaph in a similar manner are
reported in reference 2.

Sonar Tests

Dives Nos. 61 and 69 furnished opportunities to test
the effectiveness of the AN/SQS-4 and the AN/SQR-8
Mod 4 sonars in detecting and following the bathyscaph on
its descent and ascent, while maintaining voice communi-
cations through the bathyscaph acoustic telephone and two
AN/UQC-lB's. Results are omitted because of classifica-


To test the usefulness of the bathyscaph as a platform
for obtaining gravity measurements at great ocean depths,
K, V. Mackenzie obtained a LaCoste- Romberg Company
geodetic gravimeter, model G, to measure the value
in situ . This instrument has a range of 6. 000 cm/sec^
with a sensitivity of 1 x lO"'^ cm/sec^.

During Dive No. 78, gravity measurements at mid-
water were attempted. However, the vertical stability
and control were insufficient to permit a satisfactory

Success was achieved on the sea floor at a depth of
2286 meters. The value of g was found^ to be 978. 9331
cm/sec^ . This compares with a reference value of g
at the Ship Repair Facility, Apra Harbor, of 978. 5376
cm/sec^. Although this isolated measurement does not
contribute significantly to knowledge of the variations of
g with depth, it does show the suitability of a manned
deep submersible to serve as a stable platform for such
delicate instruments.




Beebe^ (1934) using the bathyscaph and Monod* using
the French bathyscaph "FNRS- 3 observed bioluminescence
down to the greatest depths reached (1400 meters). Monod
found that the bioluminescence was much less near the

In Project NEKTON I, the bathyscaph descended to
the maximum known depth in the ocean (35, 800 feet in the
Challenger Deep). During this descent and others made to
the bottom at shallower depths, bioluminescence was found
to be present at all depths, but was not necessarily contin-
uous from surface to bottom. However, the greatest abun-
dance of bioluminescence was observed between the base of
the sunlit zone (the depth near the surface where the inten-
sity of daylight masks out the weak light generated by
marine organisms) and 10, 000 feet.

The common pelagic and bathypelagic sources of bio-
luminescence are found among the protozoans, coelenter-
ates, ctenophores, euphausiids, decapod crustaceans,
salps, and fishes. Both intermittent and steady lumines-
cence can be found among these animal groups.

Observations made by lowering bathyphotometers and
by direct visual observations reveal that deep-sea faunas
predominantly display intermittent flashing. Until the work
of Clarke and Backus^ very little was known about the
absolute magnitude of the luminescent flashes of oceanic
animals under natural conditions. Relatively few laboratory
studies have been conducted on the subject other than those
by Nichols'^ (1924) and by Clarke and Backus® (1956). In
both laboratory and sea conditions, the intensity of a lum-
inescent flash at 50 centimeters was found to be approxi-
mately 0. 00005 to 0. 000075 microwatt per cm^ .

An inherent difficulty in the system employed by Clarke
and Backus, or in any cable- lowered photometer, is that it
is difficult to determine the distance of the luminous source
from the photometer. This problem can be partially re-
solved by having bathyscaph observers conduct direct visual
observations along with estimates of the intensity. Intensity
of a luminescent flash can be qualitatively estimated using
the scale employed by astronomers in describing star


brightness, a technique readily adaptable to a scientist
using the bathyscaph. Distance to the emanating source
can also be approximated.

Clarke^ has, in view of the above problem, considered
the light intensity of a given flash of point source in relation
to its possible distance from a sensing instrument. His
experiments and deductions reveal, as a best estimate,
that the maximum possible sensing range of a photometer
is about 10 meters. His calculations and conclusions seem
correct, as 10 meters represents the maximum estimated
distance that such sources can be seen by the human eye
from within the bathyscaph. This assumes equal sensitivity
between instrumental sensors and the human eye.

Virtually continuous observations to determine the
presence of bioluminescence throughout the large water
column have been made during ascents of the TRIESTE
(Dives Nos. 61, 76, 77, 78). Results are shown in table 2.
It appears that bioluminescent flashes are normal at great
depths and do not necessarily require tactile stimulation
by a source such as the moving bathyscaph. Although Dietz^
reports that i^. is an advantage to have the eddy current
behind the bathyscaph, as during the ascent, because this
stimulates organisms to luminesce; subsequent observations
have revealed that this contributes only modestly to the
flashing rate. A burble or knuckle of water does follow
behind the bathyscaph on the ascent and this usually does
elicit a small increase in the the amount of biolumines-
cence. As the maximum ascent rate of the TRIESTE is
never more than 2 meters per second, the water current
activity behind the bathyscaph is relatively slight.

The quantity of bioluminescence remained substantially
the same for conditions of descent and ascent. Exceptions
noted were the breakup of strings of point flashes and en-
tanglement of medusae in the external rigging of the
TRIESTE during ascent. It is well known that tactile
stimulation will elicit significant increases of biolumines-
cence in surface "burning water. " (However, dropping of
ballast, which should be a potent tactile stimulus in a
limited area, resulted in little bioluminescence. )

By analogy, the concentration of bioluminescence at
any one time rarely exceeds the number of stars that can
be seen in the heavens on a clear, dark night. Evidence
of virtually incessant flashing in the viewing area was
observed by Piccard (personal communication) in 1956.




Depth (feet)


^auge readings)

42 00

4800 &


6900 to
10, 500

12, 300

13, 800

Approximately 1 flash per 1/2 meter^ .
Usually single points. One fairly large
disc- shaped object with numerous
points of light.

Amount of bioluminescence remains
approximately uniform.

Bioluminescence much reduced; only
isolated points observed.

Virtually no bioluminescence present.

Single point, water virtually clear of
suspended material.

No bioluminescence observed since
12, 300 feet. Release of ballast incites
no bioluminescence.


17, 700

18, 000

18, 450

Amount of suspended material has
increased to a high quantity. Particles
reflect white. Most are inanimate.
Size average 1/8 inch, two are 3/8
inch. One pteropod observed.

One mysid. Considerable amount of
material in water. Isopod (?), white,
1/2 inch, swimming while in vertical

Pelagic annelid, Tomopteris sp. ,
2 1/2 inches, 1 inch wide including
parapodia, body 1/2 inch or less.
Two pteropods.

One mysid, 1 inch long,
in suspended animation,

resting quietly
11/8 inch


18, 540 Amount of suspended matter has

approximately doubled over what it
was earlier. Many of the particles
appear to be about 1/4 inch in diam-
eter and very light in color. Nearly
white. One mysid, one Tomopteris.

18, 600 Sea floor clearly shows the presence

of burrowing organisms. White
patches mottle the tawny sea floor,
and represent sediment brought to the
surface by burrowing animals. One
moUusk shell, similar to Astrea of
shallower water; 2 inches in diameter
at the base and about 11/2 inches high.
Water current virtually nil.

18, 600 (On leaving the bottom. ) One mysid,

one Tomopt e r i s ,

18,150 One Tomopteris .

15, 300 Some bioluminescence; four sustained

greenish-white flashes. Observation
followed by a period of no biolumines-

15, 060 Two bursts cf bioluminescence that

remained evident until the bathyscaph
passed away from the object (30 sec-

13, 500 Three greenish- white flashes.

12, 600 Two flashes.

'''2 00 A number of pieces of bioluminescence

observed. One unit appeared as a
cluster until it was broken into fine
pieces in the turbulence of the bathy-
scaph. Perhaps it was a siphonophore.
Several other points of light evident.


Depth (feet)












Euphausiid or crustacean. Visibility
70 to 80 feet.

Ten small white flashes.

One flash - none between 10, 800 and
10, 400.

Four flashes.

Six flashes. One 15- second duration

92 70 Flare-up of flashes. Quantity increas-

ing. Five or six of 30- second duration.

9075 2 00- foot interval, none; then four to

8830 five. One sustained big mass of light.

Adequate to permit viewing of grating

inside antechamber.

8780 Strings of bioluminescence being broken

up in burble. Too many to count. Four-
inch chain. Big points of 30- second
duration. Much suspended matter.

8185 Continuous biolumine scent flashing.

7990 Slight decrease. Water temperature,

3. 5°C.

7841 Short chain that appeared to be a fish

with lights on. Many other small points.

7495 String broken up.

7 346 Increase. Double of amount at 8000

feet. Full sky density. Some first

7100 About same density. Several appear

as three points in a cluster.

6900 Increasing. No void periods. Full sky.


6600 Broken animal. Bioluminescence not

as bright as isolated flashes. Weaker
lights are about one- third intensity of
first magnitude star. Majority second

6180 No change. Short periods of no flashes.

More breakup, A single 60- second
sustained glow.

5900 Ballast release caused no excitation.

5500 Increasing,

5300 Marked increase since 5500 feet,

4800 Tenfold increase over 6600 feet.

42 50 100-2 00 points present at all times.

Water temperature 5. 0°C.

4100 Same as above.

3600 Bright points increasing slightly.

3000 Same as above.

2150 Bright points increasing slightly,

2 000 Twofold increase over 4000.

1500 Detect contrast color of hull fittings.

Bright bioluminescence still visible.

1150 Bioluminescence detectable over

ambient sunlight. Magnetic value
clearly white now. Dark red paint
appears black,

1000 No longer possible to see biolumines-

cence due to daylight.



(in feet)







Few faint points.

Organisms transparent in searchlight.

Several small black fish 4 inches long;

2 4

Online LibraryAndreas B RechnitzerSummary of the bathyscaph Trieste research program results : (1958-1960) → online text (page 2 of 4)