Lake Vostok is the world’s largest known subglacial lake, buried beneath Antarctica’s ice sheet.
The lake lies beneath Russia’s Vostok Station in East Antarctica, under roughly four kilometres of ice. Radar surveys revealed a large body of liquid water, protected from the surface environment for an exceptionally long period.
Lake Vostok is about 250 kilometres long and up to 50 kilometres wide. Its water remains liquid partly because geothermal heat rises from below and the enormous pressure of the overlying ice lowers the melting point.
Scientists study the lake as a possible analogue for icy environments elsewhere, including Jupiter’s moon Europa. Direct sampling has been difficult because drilling risks contaminating an isolated ecosystem. Lake Vostok is not an ordinary surface lake and should not be confused with the smaller, exposed lake at Russia’s Antarctic research station, which shares its name.