Sat, Oct 30, 2004 page9

• Scientists search for signs of life in underground Antarctic lake

  After discovering a lake deep below Antarctic ice, scientists are now searching for the existence of organisms which could tell us about how life on earth evolved

  • By David Adam / THE GUARDIAN
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  This is the story of a lost world. A tale of mysterious creatures and thrilling exploration, of dreams, arguments and an international race for glory -- all set against the stunning backdrop of Antarctica. But mostly, this is a story about drilling. The old joke from the Yellow Pages does not ring true in this case: for drilling do not see boring.

  It all began in 1989 when Russian scientists at a remote Antarctic research field station, in the center of the mighty East Antarctic glacial plateau 1,250km from the South Pole in one direction and 1,260km from the coast in the other, started to drill a hole into the ice.

  The researchers knew exactly what they were looking for: trapped in the ice, which had steadily built up over hundreds of thousands of years, would be tiny bubbles of air that carried secrets of Earth's past climate. It worked, and the now famous Vostok (named after the station) ice core was the first to show a clear link between raised carbon dioxide levels and a warmer atmosphere over the past 400,000 years.

  But, as the scientists drilled, it became clear that something else was lurking under the ice. For years, Russian pilots in the area had noticed a strange flat region on the surface and as the drillers neared a depth of 4,000m, the ice they dragged back to the surface started to look very different. It was not snow squeezed from the surface through thousands of years of compaction, but refrozen water.

  Seismic surveys and satellite images confirmed the scientists' suspicions: lying directly underneath the Russian station, way down in the freezing depths, was a lake of fresh, liquid, water.

  Now called Lake Vostok, the scale of the underground reservoir stunned experts -- about 14,000km2 and up to 1,200m deep. More intriguingly, its icy roof has probably sealed the lake from the rest of the planet for at least 15 million years. With no sunlight and just traces of nutrients to provide energy, biologists quickly realized that if there is life in the lonely waters of Lake Vostok -- and there is life everywhere else on Earth where there is fresh water -- it might be very different from life on the rest of our planet.

  "We really don't know what's down there," said Martin Siegert, a glaciologist at the University of Bristol and an expert in subglacial lakes.

  At its most far-reaching, life that evolved in the lake from the simple organisms that drained into it millions of years ago could show us what we might find in the watery depths predicted to lie beneath the icy crust of Europa, one of Jupiter's moons and the prime candidate for finding life on another world.

  The one thing the scientists could be sure of was that puncturing the lake's surface with a dirty Russian drill loaded with 60 tonnes of kerosene to stop it freezing was not a good idea. With the bottom of the borehole just 120m above the pristine lake's frozen surface, drilling operations at Vostok were suspended in 1998.

  Debate about what to do next has swung back and forwards ever since. Until now. At a meeting earlier this month in the German port of Bremerhaven, scientists from across the world finally hammered out a plan to explore Lake Vostok. Well, nearly.

  "We want to get into Vostok eventually but we want to approach it very carefully," said Colin Summerhayes, director of the Scientific Committee on Antarctic Research in Cambridge, which oversees international efforts in Antarctica and has drawn up the new plan.

  "We're going to try out our techniques and technology on some of the smaller lakes first," he said.

  Vostok is the biggest and most famous lake underneath Antarctica, but not the only one. Some 145 have been identified so far, and more will follow. Formed by geothermal heat melting the base of the ice sheet, which then acts as an insulating blanket to stop the water refreezing, all the lakes are dark, isolated from the outside world and all pose the same problem to scientists who want to probe them for life.

  "If we find life we have to be sure that it was there before and that we didn't put it there," said John Priscu, an ecologist at Montana State University who has studied lakes in Antarctica.

  Space scientists heading to search Mars and other worlds, Europa included, face the same problem.

  Subglacial lakes only stay liquid if their ice blanket is thicker than about 3,000m, which makes them awkward to access. But some are more awkward than others, and among the easiest to explore is Lake Ellsworth in West Antarctica, about 3,400m down.

  "Lake Ellsworth is reasonably small so we can cut our teeth on that one and then move onto something bigger," Summerhayes said.

  Siegert is leading a British project, which includes scientists who worked on the ill-fated Beagle 2 mission to Mars, that aims to send a robot explorer into Lake Ellsworth within five years.

  "It's very exciting from a British point of view," he said. "We will actually be leading the way in subglacial lake exploration."

  His team wants ? 2 million (US$3.6 million) to melt a hole down to the lake using hot water -- through which a slimline robot fitted with lights and cameras will be lowered to analyse lake sediment, scan for life and retrieve water samples.

  If there is life in Lake Ellsworth, it is likely to be simple.

  "It will be basic stuff like single-celled organisms, algae, some viruses and fungi -- that kind of thing," Siegert said.

  Currently living under crushing pressure because of the weight of frozen water above, he said nothing would survive being brought to the lower-pressure surface.

  "It will just get blown apart but we'll still be putting the bits and pieces back together to identify what it was," he said.

  Under the Bremerhaven plan, if the British pull it off then next on the list would be an Italian-led expedition to the much larger Lake Concordia. Following that would be a similar body beneath the South Pole and then the jewel in the crown, Vostok itself.

  "We want people to work on particular projects at particular times so there's more of a sequence than a mad gold-rush-style scramble with everyone doing their own thing," Summerhayes said.

  Still, not everybody wants to play ball and the Russian team insists it will enter Vostok much earlier. Valery Lukin of the Arctic and Antarctic Research Institute in St Petersburg said drilling in the original Vostok borehole could resume in January.

  "I am a Russian and the first people I listen to are Russian scientists," he said.

  Within two or three years they want to puncture Vostok's seal, trusting in the lake's high pressure to drive water up the borehole and keep the less dense, contaminating drill fluids away. They will then wait for the water to refreeze, before redrilling, extracting and analyzing it.

  "Maybe this year we will drill 20m of new ice," Lukin said -- though he is still waiting for the final go-ahead from his political masters.

  A decision is expected in the next two weeks.

  Other scientists are unhappy with the plan, but are powerless to act.

  "I think it's going to be too risky for the science involved," Priscu said. "It's going to be a contaminated mess."

  "I don't like the idea. It seems we're going back to the Amundsen-Scott stuff and we don't need that. I don't think a nation has to be first any more," he said.

  For your information

  Further reading

  ■ Briefing on the lakes from the Scientific Committee on Antarctic Research can be found at: www.scar.org/treaty/atcmxxvii/ ip100subglaciallakes.pdf ■ Details of UK proposal to explore Lake Ellsworth can be found at: www.ggy.bris.ac.uk/ellsworth/index.htm ■ Study of Antarctic subglacial lakes from geophysical and numerical modelling information can be found at: www.ggy.bris.ac.uk/research/ glaciology/personalpp/siegert/ pdf1.pdf ■ Arctic and Antarctic Research Institute in St Petersburg can be found at: www.aari.nw.ru/index_en.html graphic: TT
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