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Microbial life at -13 °C in the brine of an ice-sealed Antarctic lake


Murray, AE and Kenig, F and Fritsen, CH and McKay, CP and Cawley, KM and Edwards, R and Kuhn, E and McKnight, DM and Ostrom, NE and Peng, V and Ponce, A and Priscu, JC and Samarkin, V and Townsend, AT and Wagh, P and Young, SA and Yung, PT and Doran, PT, Microbial life at -13 °C in the brine of an ice-sealed Antarctic lake, Proceedings of the National Academy of Sciences, 109, (50) pp. 20626-20631. ISSN 0027-8424 (2012) [Refereed Article]

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Copyright 2012 PNAS

DOI: doi:10.1073/pnas.1208607109


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 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.

Item Details

Item Type:Refereed Article
Keywords:astrobiology, geomicrobiology, microbial ecology, extreme evvironment
Research Division:Earth Sciences
Research Group:Physical geography and environmental geoscience
Research Field:Physical geography and environmental geoscience not elsewhere classified
Objective Division:Environmental Management
Objective Group:Other environmental management
Objective Field:Other environmental management not elsewhere classified
UTAS Author:Townsend, AT (Associate Professor Ashley Townsend)
ID Code:81200
Year Published:2012
Web of Science® Times Cited:116
Deposited By:Central Science Laboratory
Deposited On:2012-11-27
Last Modified:2015-08-06

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