Aquatic Sciences Meeting, Albuquerque 2001

PC04 Microbial Diversity

Date: Tuesday, February 13, 2001

Location: Southwest Hall

Obraztsova, A, , Scripps Inst. Oceanography, UCSD , La Jolla,92093-0202, USA, annao@ucsd.edu

Ransom, B, , Scripps Inst. Oceanography, UCSD , La Jolla,92093-0220, USA, bransom@ucsd.edu

Arias, Y, A, Scripps Inst. Oceanography, UCSD , La Jolla,92093-0202, USA, meriah@ucsd.edu

Kastner, M, , Scripps Inst. Oceanography, UCSD , La Jolla,92093-0212, USA, mkastner@ucsd.edu

Tebo, B, M, Scripps Inst. Oceanography, UCSD , La Jolla,92093-0202, USA, btebo@ucsd.edu

Mineralogical Controls On Microbiological Diversity

Little is known about the specificity of prokaryotes for different fine-grained geological substrates (i.e., clay minerals) that dominate marine and terrestrial surface environments. We investigated the possible correlations between clay minerals and the microorganisms that colonize them. Natural marine sediment collected near SIO was used as an inoculum for enrichments of sulfate-and iron-reducing bacteria with different minerals. DNA was isolated from the minerals and 300 bp fragment of the small subunit 16S r RNA genes was amplified using Bacteria-specific primers. Denaturing gradient gel electrophoresis followed by PCR and DNA sequencing of the major bands in the gel was used to determine the bacterial groups in the enrichment cultures. The dominant bacterial sequences associated with kaolinate and chlorite were most related to the genus Desulfomicrobium (95% similarity). Dominant sequences associated with quartz and montmorillonite were most similar to Desulfovibrio (87-97% similarity). Positive amplification of 16S rRNA gene fragments with Archea-specific primers was obtained from all the iron-reducing enrichment cultures. These results suggest that different minerals may exert some control on the composition of anaerobic communities.

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Aquatic Sciences Meeting, Albuquerque 2001

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