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rfmcdonaldEarly indications that Antarctica's subglacial Lake Whillans might harbour microbial life (1, 2) have been confirmed. Via Will Baird is the report from Nature.
io9's Robert Gonzalez notes the implications of this discovery for life elsewhere in the solar system, in the subsurface water oceans known to exist on worlds like Europa and Enceladus.
As at least some commenters at io9 note, Antarctica's subglacial lakes are not at all like the subsurface oceans of Europa or Enceladus in that, until geologically quite recently, Antarctica was a temperate continent on a warm Earth. Europa and Enceladus have always been outer-system ice moons. Did life ever get started in those extraterrestrial oceans (or, perhaps, get transplanted there)?
Having just completed the tortuous 48-hour journey from the South Pole to the US west coast, John Priscu is suffering from more than his fair share of jet lag. But his tiredness can't mask the excitement in his voice. After weeks of intense field work in Antarctica, he and his team have become the first to find life in a lake trapped under the frozen continent's ice sheet.
“Lake Whillans definitely harbours life,” he says. “It appears that there lies a large wetland ecosystem under Antarctica’s ice sheet, with an active microbiology.”
The lake in question is a 60-square-kilometre body of water that sits on the edge of the Ross Ice shelf in West Antarctica. To reach it, Priscu, a glaciologist at Montana State University in Bozeman, and his team had to drill down 800 metres of ice.
They arrived at their goal on 28 January, when their environmentally clean hot-water drill broke through to the lake's surface. What they found was a body of water just 2 metres or so deep — much shallower than the 10–25 metres seismic surveys had suggested, although Priscu notes that the lake may well have deeper spots.
The team put a camera down the borehole to make sure that the borehole was wide enough for sampling instruments to be deployed and returned safely. It was, and over the next few days, the scientists collected some 30 litres of liquid lake water and eight sediment cores from the lake’s bottom, each 60 centimetres long.
What precious stuff they had retrieved soon became clear under the on-site microscope. Both water and sediment contained an array of microbes that did not need sunlight to survive. The scientists counted about 1,000 bacteria per millilitre of lake water — roughly one-tenth the abundance of microbes in the oceans. In Petri dishes, the bacteria show a “really good growth rate”, says Priscu.
io9's Robert Gonzalez notes the implications of this discovery for life elsewhere in the solar system, in the subsurface water oceans known to exist on worlds like Europa and Enceladus.
Lake Whillans — like the hundreds of other subglacial lakes and waterways entombed beneath Antarctica's assorted ice shelves — is thought to harbor conditions similar to those of Jupiter's moon Europa and Saturn's moon Enceladus. Hundreds of meters below the surface of Earth's southernmost continent, pressures soar to vitality-crushing levels. Nutrient availability is minimal. Sunlight is nonexistent. Antarctica's bygone repositories of liquid water have been isolated from the rest of the world for so long, under conditions so extreme, that evidence of life in any of the continent's subsurface reservoirs would bode well for our chances of discovering life on other worlds — to say nothing of the enormous boon such a discovery would be to biological research here on Earth.
As at least some commenters at io9 note, Antarctica's subglacial lakes are not at all like the subsurface oceans of Europa or Enceladus in that, until geologically quite recently, Antarctica was a temperate continent on a warm Earth. Europa and Enceladus have always been outer-system ice moons. Did life ever get started in those extraterrestrial oceans (or, perhaps, get transplanted there)?
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