HR: 17:00h
AN: V44A-06    [Abstracts]
TI: Macrobiotic Communities of Vailulu'u Seamount, Samoan Archipelago
AU: * Young, C M
EM: cmyoung@uoregon.edu
AF: Oregon Institute of Marine Biology, University of Oregon, P.O. Box 5389, Charleston, OR 97420 United States
AU: Lee, R W
EM: rlee@mail.wsu.edu
AF: School of Biological Sciences, Washington State University, 312 Science Hall, Pullman, WA 99164-4236 United States
AU: Pile, A J
EM: apile@bio.usyd.edu.au
AF: Department of Biology, University of Sydney, Heydon Laurence Building, Sydney, NSW 2006 Australia
AU: Hudson, I R
EM: dj1@mercury.noc.soton.ac.uk
AF: George Deacon Division for Ocean Processes, National Oceanography Center, European Way, Southampton, SO14 3ZH United Kingdom
AU: Brooke, S D
EM: brooke@uoregon.edu
AF: Oregon Institute of Marine Biology, University of Oregon, P.O. Box 5389, Charleston, OR 97420 United States
AU: Ted, P
EM: twp@u.washington.edu
AF: School of Aquatic and Fishery Sciences, University of Washington, Box 355100, Seattle, WA 98195 United States
AU: Staudigel, H
EM: h.staudigel@ucsd.edu
AF: Cecil H. and Ida M. Green Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, UCSC-0225, La Jolla, CA 92093-0225 United States
AU: Hart, S
EM: shart@whoi.edu
AF: Department of Geology and Geophysics, Woods Hole Oceanographic Institution, MS 25, Woods Hole, MA 02540 United States
AU: Bailey, B E
EM: bebailey@ucsd.edu
AF: Cecil H. and Ida M. Green Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, UCSC-0225, La Jolla, CA 92093-0225 United States
AU: Haucke, L
EM: haucke@ucsd.edu
AF: Marine Biology Research Division, Scripps Institution of Oceanography, UCSD, La Jolla, CA 92093-0225 United States
AU: Koppers, A
EM: akoppers@ucsd.edu
AF: Cecil H. and Ida M. Green Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, UCSC-0225, La Jolla, CA 92093-0225 United States
AU: Konter, J
EM: jkonter@ucsd.edu
AF: Cecil H. and Ida M. Green Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, UCSC-0225, La Jolla, CA 92093-0225 United States
AU: Templeton, A
EM: alexis.templeton@colorado.edu
AF: Cecil H. and Ida M. Green Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, UCSC-0225, La Jolla, CA 92093-0225 United States
AU: Tebo, B
EM: btebo@ucsd.edu
AF: Marine Biology Research Division, Scripps Institution of Oceanography, UCSD, La Jolla, CA 92093-0225 United States
AB: Vailulu'u, the active seamount on the hotspot at the Eastern end of the Samoan volcanic chain, was the focus of two research cruises in April and June 2005 using the Pisces V submersible. Warm-water vents on the summit of a newly formed volcanic cone in the crater supported a low-diversity community dominated by thick microbial mats and the synaphobranchid eel Dysommina rugosa. Isotope and gut analyses indicated that the eels feed not on the mats but on planktonic crustaceans imported to the system from the overlying water column. The microbial mat exhibited isotopic signatures consistent with local chemosynthesis, but not methane-based chemosynthesis; A���A,A'15 N values ranged from 2-6A�A�A��_sA�A,A� and A���A,A'13C ranged from -25 to -18 A�A�A��_sA�A,A�. Apart from the eels, only two metazoans were found near vents on the volcano summit, and the isotope composition of these (a copepod and a scale worm isolated from mat samples) were consistent with microbial mat as a source of dietary C and particularly N. Vents discovered in the deeper parts of the caldera, on the southern inside wall, and on the rift zone of the western flank supported no megafaunal vent communities. The deepest part of the crater contains toxic fluids, as evidenced by abundant fish, crustacean and cephalopod carcasses. The only species that survives here is a bright red hesionid polychaete that that feeds on or near dead fish. Hexactinellids and demosponges were found on both the inside and outside walls of the volcano. Isotopes indicate that those on the inside obtain nutrition from microbes of vent origin, while those on the outside feed on oceanic plankton. The background megafauna of the outer flank was dominated by octocorals and hexactinellid sponges, with occasional asteroids, ophiuroids and crinoids. Most megafaunal organisms collected from the outer flanks were isotopically heavy, with isotope values similar to those of non-vent deep-sea animals. However, the octocoral Anthomastis collected from low-elevation breaches on the cauldera summit were intermediate in isotopic composition, indicating that they may consume particulate material derived from vent C and N.
DE: 0410 Biodiversity
DE: 4800 OCEANOGRAPHY: BIOLOGICAL AND CHEMICAL (0460)
DE: 4804 Benthic processes, benthos (0408)
DE: 4815 Ecosystems, structure, dynamics, and modeling (0439)
SC: Volcanology, Geochemistry, Petrology [V]
MN: Fall Meeting 2005