HR: 1340h
AN: OS33A-1457 [Abstracts]
TI: The Fauna Of Two New Discovered Hydrothermal Fields At 5°S And 9°33'S On The
Mid-Atlantic-Ridge
AU: Stecher, J E
EM: jstecher@senckenberg.de
AF: Research Institute Senckenberg Dep. DZMB, Sdstrand 44, Wilhelmshaven, LS 26382
Germany
AB:
Before April 2005 there was a zoogeographical puzzle to solve: Are there any hydrothermal vent communities south of the
equator the Atlantic Ocean, and if so, what will be their characteristics? Are they similar with those of the northern
Atlantic Ocean or will they differ? Before the cruise 169 of the British "Charles Darwin" research vessel started, no vent
site was discovered on the southern Atlantic Ridge. Using an autonomous underwater vehicle from WHOI, the first hydrothermal
active vent site was found at 5°S in April 2005. With the support by British and American colleagues(Chris German and
Tim Shank) the scientific crew of Meteor cruise M64/1 sampled this site at 5° first with the ROV "Quest 4000" from
Marum, University Bremen. But far in excess of this success one more vent site was discovered and investigated by the Meteor
cruise M64/1: the Lilliput Field at 9°33S on the Mid-Atlantic-Ridge. Our first results indicate that the identified taxa
of the hydrothermal fields at 5°S and 9°33S resemble the northern Logatchev community (Gebruk et al. 2000) in most
elements. Remarkable is the missing of following typical hydrothermal taxa: Decapods of the families Alvinocaridae, like
Chorocaris, and Galatheidae, echinoderms like Ophiuridae and Ventfishes of the family Zoarcidae. Obviously the Romanch
Fracture Zone act only partly as a physical barrier between vent fauna assemblages of the North and South Atlantic Oceans
(see Shank 2004). Gebruk, A.V., Chevaldonn, P., Shank, T., Lutz, R.A. & Vrijenhoek, R.C. (2000): Deep-sea hydrothermal vent
communities of the Logatchev area (14°45'N, Mid-Atlantic Ridge): diverse biotopes and high biomass. J. Mar. Biol.
Assoc. U. K. 80: 383-393. Shank, T. (2004): The evolutionary puzzle of seafloor life. - Oceanus Magazine Vol. 42, No.2
http://oceanusmag.whoi.edu/v42n2/shank.html.
DE: 0410 Biodiversity
DE: 0439 Ecosystems, structure and dynamics (4815)
DE: 0450 Hydrothermal systems (1034, 3017, 3616, 4832, 8135, 8424)
SC: Ocean Sciences [OS]
MN: Fall Meeting 2005