Lake Vostok, which has been sealed off from the world for 14 million years, is about to be penetrated by a Russian drill bit.
The lake, which lies four kilometres below the icy surface of Antarctica, is unique in that it's been completely isolated from the other 150 subglacial lakes on the continent for such a long time. It's also oligotropic, meaning that it's supersaturated with oxygen -- levels of the element are 50 times higher than those found in most typical freshwater lakes.
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.
It is located beneath Russia's Vostok Station, 4,000 metres (13,000 ft) under the surface of the central East Antarctic ice sheet. It is 250 kilometres (160 mi) long by 50 kilometres (31 mi) wide at its widest point, thus similar in size to Lake Ontario, and is divided into two deep basins by a ridge. The water over the ridge is about 200 metres (660 ft), compared to roughly 400 metres (1,300 ft) deep in the northern basin and 800 metres (2,600 ft) deep in the southern. Lake Vostok covers an area of 15,690 square kilometres (6,060 sq mi). It has an estimated volume of 5,400 cubic kilometres (1,300 cu mi) and consists of fresh water. The average depth is 344 metres (1,129 ft). In May 2005 an island was found in the center of the lake.