Добавлено: Пт Янв 07, 2011 9:49 pm Заголовок сообщения: Mysteries of Lake Vostok on brink of discovery
Mysteries of Lake Vostok on brink of discovery
16:48 05 January 2011 by Olivier Dessibourg
For 14 million years, Antarctica's vast Lake Vostok has remained tantalisingly sealed off from the rest of the world, hidden under 4 kilometres of ice. What unique forms of life might have evolved in the hidden depths?
After years of speculation we are about to find out, as a Russian drill nears the lake. The Antarctic Treaty Secretariat, the body set up to preserve the continent, has approved the comprehensive environmental evaluation carried out to ensure the reservoir is not polluted. Researchers from Russia's Arctic and Antarctic Research Institute (AARI) in St Petersburg expect to reach the water in late January.
The AARI's Valery Lukin says they have devised a clever method for sampling the lake without contaminating it. "Once the lake is reached, the water pressure will push the working body and the drilling fluid upwards in the borehole, and then freeze again," Lukin says. The following season, the team will go back to bore in that frozen water, take the sample out and analyse its contents.
"The Russians really did a good job in giving answers to all the fears raised that their actions would contaminate this unexplored environment," says Manfred Reinke, head of the ATS.
Covering an area of 16 square kilometres, and reaching down 1050 metres, Lake Vostok is isolated from the other 150 subglacial lakes found in Antarctica. Anything living in the lake is either very old, or – potentially – an unknown form of life.
The Russian science team based at Vostok station have been ready to drill into ice above the lake since 1998. But the ATS wouldn't give the go-ahead until it was satisfied that a thorough environmental assessment had been conducted to avoid any pollution of the pristine reservoir.
"The bottom of the new borehole lies at 3650 metres, more or less 100 metres above the lake," says Lukin. "Beginning late December, we will first use a mechanical drill and the usual kerosene-freon to reach 3725 metres. Then, a newly developed thermal drill head, using a clean silicon-oil fluid and equipped with a camera, will go through the last 20 to 30 metres of ice."
Yves Frenot of the French Polar Institute Paul Emile Victor in Brest, France, doubts the Russians will penetrate the lake during this Antarctic summer. "In respect to the Antarctic Treaty, they should wait 60 days after having submitted their CEE, which would bring them almost to the end of the Antarctic season."
Lukin admits time is short but says that since the exact location of the ice-water boundary is not known, "the breakthrough could well happen in a few weeks."