The Census of Marine Life project, scheduled for completion in October 2010, is discovering and cataloging as many species as possible. Five of the fourteen census projects are related to deep sea life. "Deep sea" is defined as below the level which light penetrates, which is about 200 meters. The observed species are located as deep as 5,000 meters (three miles). A total of 17,500 deep sea species have been cataloged so far, of which 5,722 are found below a depth of 1000 meters.
Here are some of the most interesting and bizarre species found so far.
A new species of "Dumbo", a finned octopod.
Clione lamacina, a snail found in Arctic and Antarctic waters.
Here is another polar species, Mimonectes sphaericus, a polar crustacean.
The image gallery at the Census of Marine Life website has some great photos, but they can't be downloaded.
An exceptionally strange group of deep sea creatures are members of the Osedax genus (bone-eating tubeworms). They devour whale bones in association with symbiotic bacteria that help in the digestion process.
They are small; their length ranges between 0.2 and 05. millimeters, and live in tubes that they build. Only the females feed on whales, The males live inside the females and feed on yolk contained inside their bodies. One female may contain dozens of males. Osedax may play a major role in carbon recycling in the deep sea.
Here are two videos on the deep sea projects.