ammonia
; dissolved organic carbon
; hydrogen
; metal
; nitrate
; nitrogen
; nitrous oxide
; organic carbon
; sodium chloride
; sulfate
; sulfur
; unclassified drug
; acidity
; Antarctica
; aquatic environment
; article
; bacterial metabolism
; bacterium
; biogeochemistry
; biota
; concentration (parameters)
; controlled study
; electron
; electron transport
; energy resource
; habitat
; ice age
; lake
; life cycle stage
; methanogenesis
; microbial diversity
; microorganism
; nonhuman
; oxidation
; pH
; phylogeny
; polar ice cap
; priority journal
; reduction
; rock
; sea
; water temperature
; Antarctic Regions
; Bacteria
; Cold Climate
; Ecosystem
; Evolution, Molecular
; Ice
; Lakes
; Microscopy, Electron, Scanning
; Molecular Sequence Data
; Phylogeny
; RNA, Bacterial
; RNA, Ribosomal
; Water Microbiology
英文摘要:
The permanent ice cover of Lake Vida (Antarctica) encapsulates an extreme cryogenic brine ecosystem (-13 °C; salinity, 200). This aphotic ecosystem is anoxic and consists of a slightly acidic (pH 6.2) sodium chloride-dominated brine. Expeditions in 2005 and 2010 were conducted to investigate the biogeochemistry of Lake Vida's brine system. A phylogenetically diverse and metabolically active Bacteria dominated microbial assemblage was observed in the brine. These bacteria live under very high levels of reduced metals, ammonia, molecular hydrogen (H2), and dissolved organic carbon, as well as high concentrations of oxidized species of nitrogen (i.e., supersaturated nitrous oxide and ∼1 mmol·L-1 nitrate) and sulfur (as sulfate). The existence of this system, with active biota, and a suite of reduced as well as oxidized compounds, is unusual given the millennial scale of its isolation from external sources of energy. The geochemistry of the brine suggests that abiotic brine-rock reactions may occur in this system and that the rich sources of dissolved electron acceptors prevent sulfate reduction and methanogenesis from being energetically favorable. The discovery of this ecosystem and the in situ biotic and abiotic processes occurring at low temperature provides a tractable system to study habitability of isolated terrestrial cryoenvironments (e.g., permafrost cryopegs and subglacial ecosystems), and is a potential analog for habitats on other icy worlds where water-rock reactions may cooccur with saline deposits and subsurface oceans.
Murray, A.E., Division of Earth and Ecosystem Sciences, Desert Research Institute, Reno, NV 89512, United States; Kenig, F., Department of Earth and Environmental Sciences, University of Illinois at Chicago, Chicago, IL 60607, United States; Fritsen, C.H., Division of Earth and Ecosystem Sciences, Desert Research Institute, Reno, NV 89512, United States; McKay, C.P., Space Science Division, National Aeronautics and Space Administration Ames Research Center, Moffett Field, CA 94035, United States; Cawley, K.M., Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80309, United States, Southeast Environmental Research Center, Florida International University, North Miami, FL 33181, United States; Edwards, R., Department of Imaging and Applied Physics, Curtin University of Technology, Perth, WA 6845, Australia; Kuhn, E., Division of Earth and Ecosystem Sciences, Desert Research Institute, Reno, NV 89512, United States; McKnight, D.M., Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80309, United States; Ostrom, N.E., Department of Zoology, Michigan State University, East Lansing, MI 48824-1115, United States; Peng, V., Division of Earth and Ecosystem Sciences, Desert Research Institute, Reno, NV 89512, United States; Ponce, A., Jet Propulsion Laboratory, Pasadena, CA 91109, United States; Priscu, J.C., Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT 59717, United States; Samarkin, V., Department of Marine Sciences, University of Georgia, Athens, GA 30602, United States; Townsend, A.T., Central Science Laboratory, University of Tasmania, Hobart, TAS 7001, Australia; Wagh, P., Division of Earth and Ecosystem Sciences, Desert Research Institute, Reno, NV 89512, United States; Young, S.A., Department of Geological Sciences, Indiana University, IN 47405-1405, United States; Yung, P.T., Jet Propulsion Laboratory, Pasadena, CA 91109, United States; Doran, P.T., Department of Earth and Environmental Sciences, University of Illinois at Chicago, Chicago, IL 60607, United States
Recommended Citation:
Murray A.E.,Kenig F.,Fritsen C.H.,et al. Microbial life at -13°C in the brine of an ice-sealed Antarctic lake[J]. Proceedings of the National Academy of Sciences of the United States of America,2012-01-01,109(50)