Scientists Found Life in a Lake Sealed Under Antarctic Ice for 15 Million Years

The Most Isolated Body of Water on Earth

When Russian drillers broke through nearly four kilometres of Antarctic ice in February 2012, they reached a lake the size of Lake Ontario that had been sealed in darkness for roughly 15 million years — and recovered traces of life that had been evolving down there ever since. It was one of the most audacious scientific achievements of the modern era, and what they found rewrote our understanding of where life can exist.

Lake Vostok sits beneath the East Antarctic Ice Sheet at roughly 78 degrees south, almost exactly under the geomagnetic south pole. The surface station above it, founded in 1957, is the same place that recorded the coldest natural temperature ever measured on Earth: minus 89.2 degrees Celsius in July 1983. The lake itself, though, is liquid. Heat from the Earth's interior, combined with the immense pressure of the ice above, keeps the water in a slim, dark, freshwater layer between bedrock and glacier.

Fifteen Million Years of Darkness

Estimates of the lake's isolation vary, but the last contact with the atmosphere occurred around 15 million years ago, when Antarctica's ice sheet thickened into the form it holds today. To put that in perspective: when Vostok was last open to the sky, the ancestors of modern humans had not yet diverged from the ancestors of chimpanzees.

It is the largest of more than 400 subglacial lakes now known to exist beneath Antarctica, and the only one big enough to have its own internal currents and tides. Any microbes living in Vostok would have spent millions of generations adapting to a place with no light, no fresh nutrients from above, and extreme water pressures. One U.S. scientist compared the achievement of reaching it to "getting to the moon."

Life Where No Life Should Be

Russian scientists announced that preliminary analyses of water samples from the lake revealed a species of bacteria not belonging to any known subkingdoms. "We call it unidentified and 'unclassified' life," said team leader Sergei Bulat of the St. Petersburg Nuclear Physics Institute. The bacteria's DNA was less than 86% similar to known bacterial DNA, indicating it was a new species.

In 2013, researchers studying the accretion ice above the lake found DNA from over 3,500 organisms, including fungi and bacteria commonly found in the digestive tracts of fish — findings that suggest the lake was once connected to the ocean and may have been a thriving ecosystem before it was cut off by the thickening ice. The sheer variety of biological signatures stunned the scientific community. According to researchers, the quantity of oxygen in the lake exceeds that found in other parts of the planet by 10 to 20 times, and any life forms found there are likely to be unique on Earth.

A Window Into Other Worlds

The discovery of microbes in Lake Vostok supports the theory that life can exist in extreme environments, surviving without sunlight by relying on chemical energy sources — with significant implications for astrobiology and the search for life beyond Earth. Scientists studying the lake believe its conditions are similar to those found on Jupiter's moon Europa and Saturn's moon Enceladus, both of which have subsurface oceans beneath thick ice crusts.

The unique conditions presented by Lake Vostok may also offer an outlook on life to be expected in extra-terrestrial subglacial environments, such as on Jupiter's moon Europa or Saturn's moon Enceladus. Working in Lake Vostok could help NASA's engineers develop methods and technologies for drilling ice on Europa to search for extraterrestrial life, while avoiding interplanetary contamination. In other words, what scientists learn from one frozen lake in Antarctica could determine how — and where — humanity searches for life across the solar system. The ice is still keeping its secrets, but the door is finally cracked open.