Russian scientists in Antarctica have drilled through nearly four kilometres of ice to reach a vast freshwater lake that has lain untouched for at least 14 million years.

Sealed deep under the ice sheet, Lake Vostok is one of the world’s last unexplored frontiers, and scientists suspect it may reveal new life forms.

It is the deepest and most isolated of Antarctica’s sub-glacial lakes, supersaturated with oxygen, resembling no other known environment on Earth.

Experts say the ice sheet acts like a blanket, trapping in the Earth’s geothermal heat and preventing the lake from freezing.

If life is found in the lake’s icy darkness, it may provide the best answer yet to whether life can exist in the extreme conditions on Mars or Jupiter’s moon Europa.

One of the researchers, Lev Savatyugin, also says samples from the lake could provide an insight into life on Earth before the Ice Age.

“There isn’t a single object on the Earth that has been isolated from the rest of the world for more than 20 million years,” he said.

“We don’t know what the climate was then, what sort of bacterial world existed then, how the genesis of life was happening. The answers could be there.”

After 20 years of stop-go drilling, the Russian team raced to chew through the final metres of ice and breached Lake Vostok in time to take the last flight out on Tuesday before the onset of Antarctica’s harsh winter.

It was here that the coldest temperature found on Earth, minus 89.2 Celsius, was recorded.

Russia must wait for the Antarctic summer to collect and study water samples, leaving the door open for US and British missions to explore two other sub-glacial lakes and beat it to be the first to answer the question of whether life exists under the polar ice.

This is probably one of the last frontiers on our planet that remains largely unknown to us.

Hidden lakes

A century after the first expeditions to the South Pole, the discovery of Antarctica’s hidden network of sub-glacial lakes via satellite imagery in the late 1990s set off a new exploratory fervour among scientists the world over.

“This is scientific exploration, this is work that no-one has ever done before,” said Martin Siegert, the head of the University of Edinburgh’s School of Geosciences.

“This is probably one of the last frontiers on our planet that remains largely unknown to us,” said Mr Siegert, who is leading a British expedition to explore Lake Ellsworth in West Antarctica in 2012-13.

If there is life in Vostok and other ice-bound lakes, it is unlikely to be anything more complicated than single-cell organisms adapted to survive in the high-pressure, sunless environment, Mr Siegert said.

“It is just imagination, we don’t really know until we go in,” he said.

John Priscu of Montana State University suspects that an oasis of life may lurk there, teeming around thermal vents.

“I hope that they can confirm unequivocally that there is indeed microbial life in the lake,” said Mr Priscu, the chief scientist on the US project to probe sub-glacial Lake Whillans.

Original: http://www.abc.net.au/news/2012-02-09/russia-drills-to-ancient-antarctic-lake/3820606