Summary: APPLIED AND ENVIRONMENTAL MICROBIOLOGY, Oct. 2005, p. 6353­6359 Vol. 71, No. 10
0099-2240/05/$08.00 0 doi:10.1128/AEM.71.10.6353­6359.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.
Diversity and Distribution of Sulfate-Reducing Bacteria
in Permanently Frozen Lake Fryxell, McMurdo Dry
Valleys, Antarctica
Elizabeth A. Karr, W. Matthew Sattley, Melissa R. Rice, Deborah O. Jung,
Michael T. Madigan, and Laurie A. Achenbach*
Department of Microbiology, Southern Illinois University, Carbondale, Illinois 62901-6508
Received 30 March 2005/Accepted 27 May 2005
The permanently frozen freshwater Lake Fryxell, located in the Dry Valleys of Antarctica, exhibits an ideal
geochemistry for microbial sulfate reduction. To investigate the population of sulfate-reducing bacteria in Lake
Fryxell, both 16S rRNA gene and metabolic primer sets targeting the dsrA gene for the dissimilatory sulfite
reductase alpha subunit were employed to analyze environmental DNA obtained from the water column and
sediments of Lake Fryxell. In addition, enrichment cultures of sulfate-reducing bacteria established at 4°C
from Lake Fryxell water were also screened using the dsrA primer set. The sequence information obtained
showed that a diverse group of sulfate-reducing prokaryotes of the domain Bacteria inhabit Lake Fryxell. With
one exception, the enrichment culture sequences were not represented within the environmental sequences.
Sequence data were compared with the geochemical profile of Lake Fryxell to identify possible connections
between the diversity of sulfate-reducing bacteria and limnological conditions. Several clone groups were highly

Source: Achenbach, Laurie A. - Department of Microbiology, Southern Illinois University

Collections: Environmental Sciences and Ecology; Environmental Management and Restoration Technologies; Biology and Medicine