HR: 1340h
AN: OS43A-0527    [Abstracts]
TI: Microbial Community Structure of the Japan Trench Cold Seeps Sediment Determined by Phospholipid Analysis
AU: * Chan, O
EM: chanolivia@gmail.com
AF: Department of Geological and Atmospheric Sciences, Iowa State University, 253 Science I, Ames, Iowa, 50011-3212, Ames, IA 50014 United States
AU: Fang, J
AF: Department of Geological and Atmospheric Sciences, Iowa State University, 253 Science I, Ames, Iowa, 50011-3212, Ames, IA 50014 United States
AU: Kato, C
AF: Department of Marine Ecosystems, Japan Marine Science and Technology Center, 2-15 Natsishima-cho, Yokosuka 237, Japan, Yokosuka, 237 Japan
AB: Seafloor cold seeps support some of the most prolific and diverse ecosystems on Earth. A multitude of microbial habitats are associated with cold seeps. The seeping fluids are enriched in reduced chemical species such as sulfide and methane. These reduced species are utilized by microorganisms to gain energy from the reduction of sulfate and oxidation of methane, the so-called anaerobic oxidation of methane. The Japan Trench is characterized by abundant chemosynthesis-based communities associated with cold seeps. Chemosynthetic communities of {\it Maorithyas hadalis} and {\it Calyptogena phaseoliformis} have been discovered at depths of over 7,000 m. In this project, sediment samples were collected from communities dominated by thyasirid bivalve {\it Maorithyas hadalis} and the vesicomyid clam {\it Calyptogena phaseoliformis} and analyzed for phospholipid fatty acids (PLFA). Our objectives were to determine and compare the microbial biomass and community structure of the two sites with different megafaunal species. Result showed the average estimated microbial biomass was 2.97*109 and 4.78*109 cells (g dry wt)-1 for {\it Calyptogena} and {\it Maorithyas} sediment, respectively. Fatty acids ranging from 12 to 22 carbons were detected. The PLFA profiles suggest the presence of methanotrophic bacteria, sulfur-oxidizing bacteria as well as sulfate-reducers. The polyunsaturated fatty acids (C 18:2 and C20:5) also allow us to trace the possible source of the sediment to the piezophilic bacteria. The assemblage of fatty acids indicates the presence of complex microbial communities in the cold seeps sediments of the Japan Trench.
DE: 4825 Geochemistry
DE: 4803 Bacteria
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting