Deep, dark and mysterious, Lake Vostok is one of the largest subglacial lakes in the world.
Buried under more than 2 miles (3.7 kilometers) of ice near Vostok research station in Antarctica, the lake filled before Antarctica froze 15 million years ago, researchers think. Covered with ice for millennia, cut off from light and contact with the atmosphere, Lake Vostok is one of the most extreme environments on Earth.
The freshwater lake may harbor a unique ecosystem of microbes and other creatures that evolved in isolation for hundreds of thousands of years. These "extremophiles" could mimic life on other moons and planets, such as Jupiter's icy moon Europa. Only meltwater from the overlying icesheet and drainage from Antarctica's subglacial waterways have touched the lake since it froze over during the Miocene period. This constant replenishment means the water in the lake may be only as old as the ice that melts to form it, some 700,000 to 800,000 years, according to ice cores. But the true age of the lake water is unknown.
DNA retrieved from lake water frozen onto the bottom of glaciers sliding over the lake suggests a diverse array of life may exist in Lake Vostok, though at low levels compared to other lakes. But despite several attempts, no teams have successfully retrieved pristine samples of lake water with evidence of life. A Russian team is currently analyzing water samples collected in early 2013 for signs of microbial life.
In 2013, scientists exploring subglacial Lake Whillans reported the first evidence for microbial life in water retrieved from a buried lake in Antarctica. There are nearly 380 subglacial lakes in Antarctica.
However, researchers have plumbed Lake Vostok's depths with remote sensing techniques, such as seismic soundings and ice-penetrating radar. Lake Vostok is much shallower on one end than the other, with the two basins separated by a ridge. Some scientists think the ridge could be a hydrothermal vent, similar to the ocean floor black smokers that teem with tubeworms. [Image Gallery: Alien Life of the Antarctic]
Geothermal energy, or heat from the Earth, keeps the temperature of the lake water hovering around 27 degrees Fahrenheit (minus 3 degrees Celsius), scientists believe.
The lake itself is 143 miles (230 km) long, 31 miles (50 km) wide and as much as 1,600 feet (500 meters) deep. Lake Vostok sits near the South Pole, within striking distance of Russia's Vostok research station in East Antarctica. The presence of a large buried lake was first suggested in the 1960s by a Russian geographer/pilot who noticed the large, smooth patch of ice above the lake from the air. Airborne radar experiments by British and Russian researchers in 1996 confirmed the discovery of the unusual lake.
Correction: This article was updated Aug. 14, 2013, to include the correct temperature of the water in Lake Vostok.