Conchologists and malacologists:
For those of you into really obscure but interesting molluscs, there
is a new handbook out which describes the molluscan fauna associated
with some of the known deep-sea hydrothermal vents around the world's
continental spreading axes:
Desbruyeres, D. and M. Segonzac. 1997. Handbook of Deep-Sea
Hydrothermal Vent Fauna. Editions IFREMER, Brest. 279 p.
This first edition was published under the auspices of InterRidge, an
international consortium of scientists/institutions conducting
research on and around the many vent systems at oceanic spreading
centers discovered since 1977. This was when remarkable
chemosynthetic communities ("the biological discovery of the century")
were first discovered on manned submersible dives on the 2500-m deep
crest of the Galapagos Rift. The book was actually meant to allow sub
pilots and scientists to recognize and collect the most valuable
(scientifically) forms on expensive dives with limited bottom time,
and as an ID guide in the lab. Typically the chemo-communities and
vent habitats are in waters from ~400 to 4,000m in depth.
Unfortunately, this volume costs about $175 on sale, but those of you
at academic institutions might be able to get your library to get it
for you. Pages 109-160 are devoted to the gastropods, bivalves and
cephalopods, and the rest is everything from sponges to fishes.
(Whew, some of the fish are ugly!) There are about 70 gastropods
mentioned, some (many) of which have not received specific names.
None have common names, and few are really pretty. There seem to be
some really primitive forms but no neopilinas. New species are being
described all the time. For those of you who are restricted to the
continental shelf <200m, these animals may prove interesting.
Actually, three genera, Acharax, Calyptogena, and Bathymodiolus, with
their several species, directly contribute to the chemosynthetic
fixation of carbon in the ecosystem using symbiotic chemoautotrophic
bacteria in their gills. Some are living in areas where water over
350 degrees C (660 degrees F) is issuing out of the rocks. Most
species hang out in the community, presumably for food.
Incidentally, similar forms have been found here in the Gulf of Mexico
at cold seeps at less than 1,000m depth. But here they eat natural
hydrocarbons seepage (methane) rather than hydrogen sulfide.
This ain't Sanibel Island, baby! You thought Janthina had strange
habits.
Robert M. Avent, Ph.D.
Oceanographer
Minerals Management Service
New Orleans.
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