Aquatic Sciences Meeting, Albuquerque 2001

SS14 Microbial Diversity (Disciplinary Connections)

Date: Monday, February 12, 2001, Time: 11:15:00 AM

Location: Brazos

Cottrell, M, T, University of Delaware, Lewes, USA, cottrell@udel.edu

Kirchman, D, L, University of Delaware, Lewes, USA, kirchman@udel.edu

DOM CONSUMPTION BY THE DOMINANT GROUPS OF MARINE BACTERIA

We have learned much about bacterial diversity in the ocean, but comparably little about metabolic functions of the numerically dominant bacterial groups. It is well known that heterotrophic bacteria are important consumers of dissolved organic matter (DOM), but how microbial diversity impacts DOM consumption is not clear. In order to test hypotheses about how community composition influences DOM consumption, we use fluorescence in situ hybridization (FISH) and microautoradiography together with FISH to assess DOM uptake by various bacterial groups. Our work and the work of others indicate that the Cytophaga-Flavobacter group may be especially abundant, suggesting a proportionally large contribution to DOM consumption. In the Delaware Bay estuary and the coastal Pacific Ocean we are determining which bacteria consume the DOM compounds that support a large fraction of bacterial production, e.g. protein and amino acids. We are also examining thymidine and leucine uptake to assess differences in bacterial production and total DOM consumption by numerically dominant versus rare bacterial groups. Initial results indicate that bacteria in the Cytophaga-Flavobacter group are important consumers of high molecular weight DOM.

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Aquatic Sciences Meeting, Albuquerque 2001

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