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DEEP-SEA BIOLOGY
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| NOTE: if you use or copy any pictures, please writer for permission (see MAIN PAGE for instructions) |
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DEEP-SEA BIOLOGY
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| NOTE: if you use or copy any pictures, please writer for permission (see MAIN PAGE for instructions) |
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III. Deep-Sea RESEARCH AT SEA: updated
8/06 with Alvin information; see new VENTS page for 2007 Alvin photos
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| EQUIPMENT FOR DEEP-SEA BIOLOGY A. SHIPS AND NETS: Studying the deep sea requires properly outfitted research ships (R/V for research vessels), with cranes and winches. Examples of ones we have used are the Wecoma of Oregon State Univ., the Thomas G. Thompson of Univ. Washington, and the Atlantis of WHOI . --Research with trawls and dredges is a round-the-clock process. It involves hours of free time as the net goes down then up. During this time we analyze samples and data, sleep, eat, or relax with books, movies, games, watching the sea. This is followed by intense teamwork when the net returns as the fishes and invertebrates have to be sorted, dissected, analyzed and preserved before they decay. See pictures to the left and below. B. SUBMERSIBLES/ROVs: D. CAMERAS and OTHER PERMANENT INSTRUMENTS: Other deepsea research is using cameras and other instruments on platforms on the seafloor, or on buoys at the surface. Examples: Hawaii H2O Deepsea Observatory, Mbari's Ocean Observing System (MOOS), the New Millenium Observatory (NeMO) on the Juan de Fuca ridge, and the Neptune Undersea network off western USA and Canada. E. CORING DEVICES, WATER SAMPLERS, Etc.: There are also a variety of other devices which can be deployed into the deep with a crane and winch on research ships. One example is a multicoring device (picture above) which plunges into the seafloor and collects cores of sediment. Another is a Conductivity-Temperature-Depth (CTD)sensor and water sampler (see picture, above). |
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| 1. Operating otter
trawl After deploying the "otter" trawl, we took 2 hours to feed 6000m (almost 4 miles) of cable out to insure the net hit bottom at 2900m. Then we trawled on the bottom for 2 hrs, then took another 2 hrs to haul it in |
2. Sunrise at sea (4/97) --we work around the clock in "watches" (like shifts on land) when trawling or using an ROV. |
3. Sunset at sea (6/06) --I thought I saw the famous "green flash" after one sunset. However, astronomer Andrew Young of SDSU reports this flash, though often real, may sometimes be an illusion resulting from red sunset light bleaching out our red retinal cones, leaving our eyes to see yellow light as green (New Scientist, 20-June-98, p.5) |
4. Porpoises "surfing" Dolphins and porpoises occasionally ride the ship's bow wave. In 1992 it was shown that this saves these animals considerable locomotory energy (of course, they may also be having fun!). Click SURFACE button at bottom of page to get more pictures and videos of porpoises in the wild |
5. Typical catch of abyssal invertebrates (plus a midwater hatchetfish), from an otter trawl |
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| 6. ROV on deck
of Thompson Oceanic Explorer sits on the deck of the ship |
7. ROV launch -- picked up by crane and lifted to the water |
8. ROV manipulator at work --arm collects specimens and experimental equipment |
9. ALVIN launch --the A-frame drops it slowly into the water, while swimmers (specially trained divers) wait in an Avon boat to remove the ropes |
10. Inside ALVIN -- 1 pilot and 2 "observers" fit snugly inside the titanium sphere, each with a porthole window...my first dive!* [photo of me by Tina Treude] |
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| 11. ALVIN at work -- the pilot deftly uses the leftside manipulator arm to scoop up sediment and seep clams. During one dive, a cheeky squid attacks the arm! |
12. ALVIN returns --swimmers reach the Alvin after it surfaces to get the sub ready for recovery |
13. Alvin Recovery 1 -- the swimmers perform the sometimes-dangerous task of hooking the A-frame ropes to the Alvin |
14. Alvin Recovery 2 --after securing ALVIN, the swimmers jump off the sub to swim back to the Avon |
15. Alvin "baptism" --after returning from your first dive in ALVIN, you are ceremoniously greeted with a bucket of icewater and a seawater hosedown [photo by Andrew Thurber] |
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| IV.A. HIGH PRESSURE and HIGH SULFIDE |
  Movie of methane vent, near which hydrogen sulfide is produced by microbes |
PRESSURE: High hydrostatic pressure (from the
weight of the water column overhead) squeezes anything with an air chamber,
such as fishes with swimbladders. Many deep-sea fishes do have fat-filled
or vestigial swimbladders to avoid this problem, but some do have air-filled
ones. These require considerable energy to inflate, and they expand (often
lethally) when the fish is hauled to the surface. Pressure does not cause
large-scale compression of most deepsea life due to the absence of air chambers,
but it affects all life at a microsopic scale. It forces water molecules
to stay densely bound to charged molecules, which interferes
with critical binding events in cells (such as an energy-yielding molecule
binding to an enzyme). For pressure adaptations,
see below.
The HIGHEST PRESSURES are found in the Challenger Deep of the Mariana Trench and the Mindanao Trench in the western Pacific. They are almost 36,000 ft or 11,000 m deep with almost 1100 atm of pressure (explored by a Japanese unmanned submersible, "Kaiko", which was unfortunately lost at sea in Sept. 2003). For depth limits of submersibles and life, see the Smithsonian's How Deep Can They Go page, and Extreme Science's Deep Ocean Creatures page. SULFIDE: Deep-sea animals at hydrothermal vents and gas seeps face another stress: high levels of hydrogen sulfide (H2S), a gas normally toxic to animals. However, giant tubeworms and certain clams and mussels at vents and seeps rely on sulfide-metabolizing bacterial symbionts in their internal tissues. Somehow the animals avoid sulfide toxicity--by binding sulfide to special proteins or converting it into non-toxic molecules. For our work on sulfide adaptations, see section 2 below. For pictures, see Seeps and Vents page |
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| 1. Trawl and Alvin dive sites off Oregon; click here for schematic diagram. [3-D images of the seafloor can be see in Scientific American June 1997 (Oregon coast on p.84)] | 2. Styrofoam head before and
after a trip on the ALVIN Hydrostatic pressure increases by 1 atm with each 10m of depth. This shows effects of 50 to 90 atm pressure on a styrofoam head taken to 520m and 906m on the Alvin (images at same scale) |
3. Swimbladder decompression --a rattail hauled for 2 hrs to surface from 2850. The air-filled bladder cannot be adjusted fast enough for low pressure, and it expands out the mouth. |
4. Swimbladder expansion effect Expanding swimbladder may push on eyes |
5. A transparent squid visits
Alvin. Squids and most animals in the oceans do not have air chambers in them, so they do not suffer from large-scale pressure effects. However, they do have to cope with microscopic effects on proteins and membranes; see OUR PRESSURE RESEARCH below. |
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| IV.B. OUR DEEP-SEA RESEARCH |
| 1. PRESSURE ADAPTATIONS High pressure traps water molecules at a high density around charged molecules, interfering with critical binding events in cells involving proteins. Dr. Joe Siebenaller of L.S.U. and other researchers have found that many proteins in deep-sea fishes somehow compensate for this effect. However, not all deep-sea proteins are pressure resistant. Pressure also makes membranes more rigid, impairing transport functions, etc. Researchers have found that deep-sea organisms have unsaturated lipids in their membranes to "loosen" them up. Unsaturated lipids (an example is vegetable oil) have mixed C-C single bonds and C=C double-bonds that prevent the lipid chains from stacking tightly together, making the lipid or fat more liquidy. In contrast, saturated lipids have all C-C single bonds that stack together, making the lipid or fat more rigid (an example is butter). In my laboratory, we have found that deep-sea fishes and some invertebrates have the highest known levels of trimethylamine oxide or TMAO (see below). This is a common compound in many marine animals, used to help maintain water balance against the high salinity of the sea. If your computer had "RealOdor" or "QuickSmell" technology, you'd recognize TMAO--it and its breakdown product, TMA, are what makes marine animals smell fishy. TMAO is also a stabilizer of proteins (helping these biological molecules remain functional when perturbed), and we have considerabl evidence (see example below) that it may be very high in these animals in order to help pressure-sensitive proteins overcome pressure inhibition (perhaps by helping to remove dense water from charged molecules). See references by Gillett, Kelly, Yancey below, and New Scientist news story (1999).
-- Recently, we analyzed deep clams from cold
seeps and found they have an unusual compound first reported by Alberic
and Boulegue in 1990: serine-phosphoethanolamine-X (where X is
an unknown). We discovered that this compound increases with depth in
clams from 1100 to 6400m depth. It may help protect proteins from pressure
effects (Fiess et al.). |
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| RIGHT: Structure of TMAO; and GRAPH of Effects of TMAO on Lactate Dehydrogenase (LDH) from a rattail (=grenadier) fish. After 8 hr at 1000 atm, this enzyme in water lost much of its activity, but with TMAO it lost much less. LDH is an enzyme that is crucial for burst activity in muscles. |  .
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RIGHT: Examples
of laboratory high-pressure devices that we've used. |
 George Somero's (Stanford) chamber for measuring enzyme activity under pressure |
Jeff Drazen's (U. Hawai'i) trap for large fish. |
 Ray Lee's (WSU) chambers for small animals |
 Hypotaurine |
2. SULFIDE ADAPTATIONS We discovered the sulfur compound methyltaurine as a dominant osmolyte in Lamellibrachia seep tubeworms. Its function is unknown, but as a methylamine, it may help counteract pressure effects (Yin et al. 2000). REFERENCES: |
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