SS2.06 Microbial Diversity in Time and Space
Date: Tuesday, June 11, 2002
Location: Poster Session - VCC
 
HodgesLR, University of Georgia, Athens, USA, lizah@arches.uga.edu
Bano, N, , University of Georgia, Athens, USA, nasreen@arches.uga.edu
Hollibaugh, J, T, University of Georgia, Athens, USA, aquadoc@arches.uga.edu
Yager, P, L, University of Georgia, Athens, USA, pyager@arches.uga.edu
 
BACTERIAL COMMUNITY STRUCTURE IN THE CHUKCHI SEA: DIFFERENCES BETWEEN FREE-LIVING AND PARTICLE-ASSOCIATED ASSEMBLAGES IN HIGH AND LOW POM ENVIRONMENTS
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The composition of summertime Chukchi Sea (70–73 N, 158–167 W) bacterial assemblages under varying primary production regimes was investigated using seawater samples from four stations. Free-living (3 um-filtered, FL) and particle-associated (unfiltered, FL+PA) assemblages were examined using denaturing gradient gel electrophoresis (DGGE) of amplified 16S rRNA. Ribotypes from bacteria isolated from unfiltered seawater were compared to DGGE fingerprints. Nutrients, chlorophyll a, particulate organic matter (POM), and bacterial and viral abundance were also measured. Station richness and similarity between filtered (FL) and unfiltered (FL+PA) samples were determined as the number of bands and by comparison of DGGE patterns, respectively. Decreased richness and similarity between FL and PA assemblages was observed in high POM (5-12 bands, 61-75% similarity) versus low POM (13-22 bands, 88-96% similarity) regions. Partial correlation analysis revealed POM as the most significant factor determining bacterial abundance (r>0.67, n=15). Viral abundance correlated best with bacterial abundance. High POM concentrations may therefore increase bacterial and viral abundance while reducing richness of the bacterial assemblage. Differences between FL and PA assemblages, however, appear greater in regions of high POM.