Mail Buoy
May 22, 2005
Students in the 4th and 8th grades from the Rodeph Sholom School in New York City sent the following questions for scientists on the Galápagos Rift expedition. Biologist Rhian Waller from the Woods Hole Oceanographic Institution answers.
1) What is the temperature at the bottom of the ocean?
This depends on where you are and how deep you go. Here at the Galapagos Rift the temperature will be around 2 degrees Celcius (36°F) at areas surrounding the vents. The low-temperature venting we have found can have temperatures up to 20 degrees Celcius (68°F). Vents elsewhere can be hot enough to melt lead (327 degrees Celcius, or 620°F).
2) Are you finding new species or life forms that have never been seen before?
Always. Nearly every biology research cruise will find new species, though they may not be recognized as such until they are brought to land and examined by specialized taxonomists.
3) Can those life forms be brought to land?
Deep-sea animals are often hard to bring back to land alive because of the differences in the environment. However there are a few specialized tanks that some researchers use that can keep the animals collected in their natural temperature and pressure. However vent animals are especially difficult to keep alive because they rely on chemicals produced by vents (chemosynthesis) for survival, something very difficult to re-create.
4) What can you see down there?
There is a lot to see on the bottom of the ocean. On the way down in Alvin has its lights shut off to conserve battery power. As you descend in the dark, you can see the bioluminescence produced by jellies and fish, and once on the seafloor Alvin turns its lights on and you can see all the animals that inhabit the deep-sea, such as starfish, crabs, corals and vent fauna.
5) How do creatures exist with so much pressure against them?
Deep-sea animals have evolved many different strategies to deal with the immense pressure at depths. Most invertebrates have no air spaces, and so are not affected by the changes in pressure and some even use the water as part of their skeleton (anemones and sea squirts are a few). Other, more mobile fauna, such as fish, have swim bladders or oily livers to aid them in traversing different depths. Read more in the Deep Sea Biology hot topic on the Dive and Discover website.
6) Does your body feel differently down there?
The slightly higher carbon dioxide concentrations in the sub can make you have a headache or feel slightly tired, but otherwise the only difference from land is that it can be cold. There are no heaters in Alvin.
7) Do you have to compress as you come up?
No, the part of Alvin where people sit is a special sphere that keeps the pressure the same as at the surface, so there is no need to de-compress as divers do.
8) What happens if somebody gets sick down there, or there is an emergency?
The Alvin pilots are all very well trained to deal with emergencies and the ship is always close by when the sub is in the water, so if there is a real emergency the pilot will end the science mission and Alvin will come to the surface to be recovered.
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