A microbial ecosystem beneath the West Antarctic ice sheet
There has been active debate over microbial life in Antarctic subglacial lakes owing to a paucity of direct observations from beneath the ice sheet and concerns about contamination in the samples that do exist; here the authors present the first geomicrobiological description of pristine water and s...
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Veröffentlicht in: | Nature (London) 2014-08, Vol.512 (7514), p.310-313 |
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Zusammenfassung: | There has been active debate over microbial life in Antarctic subglacial lakes owing to a paucity of direct observations from beneath the ice sheet and concerns about contamination in the samples that do exist; here the authors present the first geomicrobiological description of pristine water and surficial sediments from Subglacial Lake Whillans, and show that the lake water contains a diverse microbial community, many members of which are closely related to chemolithoautotrophic bacteria and archaea.
Abundant microbes in subglacial Lake Whillans
Whether there is microbial life in subglacial lakes in the Antarctic has been a matter of controversy, as early results were compromised when it was discovered that contamination may have occurred during drilling. Discovered less than a decade ago using satellite data, Lake Whillans lies beneath some 800 metres of ice on the lower portion of the Whillans Ice Stream (WIS) in West Antarctica and is part of an extensive and evolving subglacial drainage network. In the first study to sample Antarctic subglacial waters directly, analysis of sediments obtained by the WISSARD drilling program shows that Lake Whillans' water contains more than 3,900 different types of bacteria and archaea, including one closely related to the nitrite oxidizing betaproteobacterium '
Candidatus
Nitrotoga arctica', which comprised 13% of the sequence data. The lake waters contain a diverse range of metabolically active microorganisms, many of which seem to gain nutrients from the melting ice and from the rock and sediment beneath the ice.
Liquid water has been known to occur beneath the Antarctic ice sheet for more than 40 years
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, but only recently have these subglacial aqueous environments been recognized as microbial ecosystems that may influence biogeochemical transformations on a global scale
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,
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,
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. Here we present the first geomicrobiological description of water and surficial sediments obtained from direct sampling of a subglacial Antarctic lake. Subglacial Lake Whillans (SLW) lies beneath approximately 800 m of ice on the lower portion of the Whillans Ice Stream (WIS) in West Antarctica and is part of an extensive and evolving subglacial drainage network
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. The water column of SLW contained metabolically active microorganisms and was derived primarily from glacial ice melt with solute sources from lithogenic weathering and a minor seawater component. Heterotrophic and autotrophic production data together with small subunit ri |
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ISSN: | 0028-0836 1476-4687 |
DOI: | 10.1038/nature13667 |