Bernhard, J. M.. University of South Carolina, jmbernha@sph.sc.edu
Bowser, S. M.. Wadsworth Center, bowser@wadsworth.org
Buck, K. R.. Monterey Bay Aquarium Research Institute, buku@mbari.org

 
MEIOFAUNA OF THE SANTA BARBARA BASIN BEGGIATOA MAT: A SYMBIOSIS-DOMINATED COMMUNITY
 
Sediments of the bathyal Santa Barbara Basin (SBB; 34o15'N, 120o02'W) are bathed in severely dysoxic to anoxic water (typically <5uM or 0.1mL/L O2) containing considerable sulfide concentrations (>1uM H2S). Previous studies of SBB sediments concluded that few taxa besides the filamentous, sulfide-oxidizing bacteria Beggiatoa inhabited these seemingly hostile conditions; the eukaryotic meiofauna have been largely ignored or are assumed absent. Using a novel method that preserves the life position of organisms, we observed that an eukaryotic meiofaunal community thrives in Beggiatoa-laden SBB sediments. Members of the benthos include numerous species of protists (foraminifera, flagellates, ciliates) along with two species of nematodes, a previously undescribed polychaete, an undescribed gastrotrich, and an epifaunal gastropod. A survey using independent methods (TEM/SEM and DAPI) showed that the diverse, abundant SBB eukaryotic community is dominated by symbiotic relationships with bacteria. Dominance is demonstrated by the high proportion of putatively symbiotic taxa (>75%), the large biovolume of such taxa, and their high abundance. A comparison with the community from a similar but more aerated site suggests that the Santa Barbara Basin can be considered a
 
Day: Tuesday, Feb. 2
Time: 10:45 - 11:00am
Location: Sweeney Center
 
Code: SS27TU1045S