Tim Radford
Scientists are poised to explore a mysterious lost world more than 3,2km below Antarctica. A huge lake, insulated by millions of years of ice, could hold living creatures that inhabited the planet more than 30-million years ago.
British, French, German, Russian and American scientists met in St Petersburg recently to agree on what will, in effect, be a landing on another planet: the painstaking venture into a body of water the size of Lake Ontario, more than 3km under the icecap at the Russian base of Vostok.
The lake was “mapped” by space-based and ground-based instruments in 1996, and the Russians have penetrated to within 136,5m of the surface of the water. But then the drilling had to stop.
The researchers face a dilemma. They have to find a way to explore the mysterious world of Lake Vostok without contaminating it with life from the surface.
They know there will be forms of life down there: Russian and American microbiologists have been examining microbes in samples of ice laid down 400 000 years ago.
“We’ve found some really bizarre things -things that we have never seen before,” said Richard Hoover of Nasa. He and his Russian colleague have given the microscopic creatures temporary nicknames, such as Sphere, Klingon, Mickey Mouse and Porpoise. The discovery at such depths raises the hope that even stranger things lie waiting to be discovered under Vostok.
Dr Cynan Ellis-Evans of the British Antarctic Survey, one of the experts at the St Petersburg meeting, said the researchers were likely to use a hot-water lance to cut deeper into the ice. Then they plan to lower a thermal probe, which will sterilise itself as it descends. The ice will freeze again and close behind it. When the “cryobot” reaches the water, it will release a “hydrobot” to begin sampling the chemistry of the lake.
“We are expecting to find new things – and yes, it is like going to another planet,” he said. “People who work on Martian environments and the Jovian system all came along and said it had exactly the same feel.”
Nobody knows why lakes should exist under the largest body of ice on the planet. Antarctica was once a mild, forested landscape: even now, geologists are still discovering fossil ferns and carnivorous dinosaurs in the polar mountains.
The glaciers began to close over the continent 40-million years ago. Lake Vostok could be in a rift valley – a deep fissure in the continent’s crust – and if it is, the huge depth of sediment below the water could be a “time capsule” of the planet’s history.
Some geologists argue that there could be some form of volcanic heat providing the energy for unusual forms of life.
But there are other hypotheses: for instance, ice may have melted to form the lake as it sheared over the bedrock.
“I’m more of the feeling that there wasn’t a lake to start with: that one evolved in more recent times,” said Ellis-Evans.
The voyage of discovery will take years. Nasa scientists regard the project as a rehearsal for the exploration of the ocean of Jupiter’s moon, Europa – another mysterious body of water, trapped under kilometres of ice.
Life depends on water, and Mars once had rivers but is now arid. American scientists want to launch an orbiter to explore Europa – and then devise a nuclear-powered probe to drive through the crust and into the ocean beneath the surface.
They expect to learn valuable lessons from Lake Vostok. Other researchers hope to learn a lot more about planet Earth.
Antarctica is 58 times as big as Britain, and more than 99% of it is covered in thick ice -but there could be hundreds of lakes below the icesheet.
“Every single one of them could be, potentially, of significance,” said Ellis-Evans. “This is a whole new world opening up for us.”