Aquatic Sciences Meeting, Albuquerque 2001

PC04 Microbial Diversity

Date: Tuesday, February 13, 2001

Location: Southwest Hall

McCliment, E, A, University of Delaware, Lewes, USA, emcclim@udel.edu

Luther, G, W, University of Delaware, Lewes, USA, luther@udel.edu

Cary, S, C, University of Delaware, Lewes, USA, caryc@udel.edu

MICROBIAL BIODIVERSITY AND GEOCHEMISTRY IN THE HYDROTHERMAL SEDIMENTS OF THE GUAYMAS BASIN.

The ridge axis of the Guaymas Basin is covered in a thick layer of geothermal sediments characterized as having high levels of hydrocarbons as well as other unique chemical conditions. Microbial and geochemical interactions are tightly interwoven in this environment where intense redox and temperature gradients allow the evolution of metabolic pathways uniquely adapted to these extreme conditions. By integrating geochemical analyses with molecular genetic techniques, a highly diverse microbial community has been identified whose structure is mediated by local chemical gradients. Although the sediment in the Guaymas Basin is dominated by sulfate reduction, chemical analyses show high levels of ammonium (288-426uM) and nitrate (15-75uM) at depths below that where sulfate becomes depleted. Investigations using molecular probes diagnostic of specific metabolic pathways indicate the genetic capability for microbially mediated sulfate reduction, methanogenesis and ammonium oxidation. Microelectrode profiling of sediment cores shows H2S and FeS levels sharply increasing with depth. Further chemical analyses will be presented reporting levels of possible oxidants in the sediment core, as well as molecular investigations into the diversity and expression of these and other metabolic genes.

This Session Listing

Aquatic Sciences Meeting, Albuquerque 2001

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