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Applied and Environmental Microbiology, November 2005, p. 6986-6997, Vol. 71, No. 11
0099-2240/05/$08.00+0 doi:10.1128/AEM.71.11.6986-6997.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.
Suzanne P. Anderson,2
Martin Sharp,3
Julia Foght,4 and
Brian D. Lanoil1*
Department of Environmental Sciences, 2217 Geology Building, University of California, Riverside, California 92521,1 Institute of Arctic and Alpine Research and Department of Geography, University of Colorado at Boulder, UCB 450, Boulder, Colorado 80309-0450,2 Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2E3,3 Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2E94
Received 14 March 2005/ Accepted 13 June 2005
Viable microbes have been detected beneath several geographically distant glaciers underlain by different lithologies, but comparisons of their microbial communities have not previously been made. This study compared the microbial community compositions of samples from two glaciers overlying differing bedrock. Bulk meltwater chemistry indicates that sulfide oxidation and carbonate dissolution account for 90% of the solute flux from Bench Glacier, Alaska, whereas gypsum/anhydrite and carbonate dissolution accounts for the majority of the flux from John Evans Glacier, Ellesmere Island, Nunavut, Canada. The microbial communities were examined using two techniques: clone libraries and dot blot hybridization of 16S rRNA genes. Two hundred twenty-seven clones containing amplified 16S rRNA genes were prepared from subglacial samples, and the gene sequences were analyzed phylogenetically. Although some phylogenetic groups, including the Betaproteobacteria, were abundant in clone libraries from both glaciers, other well-represented groups were found at only one glacier. Group-specific oligonucleotide probes were developed for two phylogenetic clusters that were of particular interest because of their abundance or inferred biochemical capabilities. These probes were used in quantitative dot blot hybridization assays with a range of samples from the two glaciers. In addition to shared phyla at both glaciers, each glacier also harbored a subglacial microbial population that correlated with the observed aqueous geochemistry. These results are consistent with the hypothesis that microbial activity is an important contributor to the solute flux from glaciers.
Present address: Department of Earth Sciences, Montana State University, Bozeman, MT 59717.
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