Lake Vostok

A freshwater lake under about 4 km of ice beneath Russia's Vostok Station in central East Antarctica, first detected by airborne radio-echo survey in 1974-75 and confirmed by satellite in 1993. A 2013 report of a new bacterium in its water was later put down to contamination.

In a 1996 paper in Nature, A. P. Kapitsa, J. K. Ridley, G. de Q. Robin, M. J. Siegert and I. A. Zotikov described a big, deep body of fresh water buried beneath central East Antarctica's ice. Radio-echo sounding from aircraft in 1974-75 first detected it: a lake about 10,000 square km in area, of unknown depth, under roughly 4 km of ice. Satellite altimetry in 1993 confirmed its extent and showed it to be ten times bigger than any other known lake beneath ice. Wikipedia places it beneath Russia's Vostok Station and calls it the biggest of the 675 subglacial lakes known in Antarctica.

Wikipedia reports that researchers from Germany, Russia and Japan found in April 2005 that its water rises and falls with tides, its surface rising about 12 mm as the Sun and Moon shift. The water sits in total darkness at 355 bar of pressure and is expected to hold plenty of oxygen, which has led to speculation that anything living there could have evolved in its own way. Researchers suggest that a magnetic anomaly of 1 microtesla on the lake's east coast, about 105 by 75 km, may come from thinner crust there. BBC News reported in 2011 that, by scientists' estimates, the sealed-off lake has probably kept the same conditions for around 15 million years.

In 2013 The Telegraph passed on reports that Russian scientists had found a wholly new kind of bacterium in the lake. NBC News wrote later that year that those findings had since been attributed to contamination. NBC also covered a separate study in PLOS ONE whose authors said they took great care to rule contamination out. They argued that the broad range of DNA sequences they found fitted what a lake under a glacier might hold, and they found more organisms in samples taken nearer the lake surface.