Insights from the metagenome of an acid salt lake: the role of biology in an extreme depositional environment.
The extremely acidic brine lakes of the Yilgarn Craton of Western Australia are home to some of the most biologically challenging waters on Earth. In this study, we employed metagenomic shotgun sequencing to generate a microbial profile of the depositional environment associated with the sulfur-rich sediments of one such lake. Of the 1.5 M high-quality reads generated, 0.25 M were mapped to protein features, which in turn provide new insights into the metabolic function of this community. In particular, 45 diverse genes associated with sulfur metabolism were identified, the majority of which were linked to either the conversion of sulfate to adenylylsulfate and the subsequent production of sulfide from sulfite or the oxidation of sulfide, elemental sulfur, and thiosulfate via the sulfur oxidation (Sox) system. This is the first metagenomic study of an acidic, hypersaline depositional environment, and we present evidence for a surprisingly high level of microbial diversity. Our findings also illuminate the possibility that we may be meaningfully underestimating the effects of biology on the chemistry of these sulfur-rich sediments, thereby influencing our understanding of past geobiological conditions that may have been present on Earth as well as early Mars.
Science, Technology, and International Affairs, Georgetown University, Washington, District of Columbia, United States of America.
Sarah Stewart
SS
Johnson
Graduate Program in Biotechnology and Bioengineering, Harvard University Extension, Cambridge, Massachusetts, United States of America.
Marc Gerard
MG
Chevrette
Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, United States of America; Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, United States of America.
Bethany L
BL
Ehlmann
Department of Geology and Geography, West Virginia University, Morgantown, West Virginia, United States of America.
Kathleen Counter
KC
Benison
D001105:Archaea / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D001419:Bacteria / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D019015:Geologic Sediments / Q000032:analysis / Q000382:microbiology; D060106:Lakes / Q000032:analysis* / Q000382:microbiology*; D053858:Metabolic Networks and Pathways; D054892:Metagenome; D056186:Metagenomics; D054712:Salinity; D012492:Salts / Q000737:chemistry; D017422:Sequence Analysis, DNA; D013455:Sulfur / Q000032:analysis* / Q000378:metabolism; D014904:Western Australia
D012492:Salts; C017082:brine; D013455:Sulfur