By Quirin Schiermeier
The pitch-black lakes hidden beneath Antarctica's ice sheet will finally start to release their secrets next year. At a meeting last week, scientists from Russia, the United Kingdom and the United States described their plans to explore the planet's last uncharted ecosystems by drilling into three very different examples of these subglacial lakes.
Over the past 40 years, radar imagery has revealed around 150 freshwater lakes of various sizes and ages beneath the massive Antarctic ice sheet. Some have been isolated from the outside world for millions of years, raising the possibility that they hold unique life forms. The dark, nutrient-deprived environment of the lakes could resemble conditions on Jupiter's moon Europa, which is assumed to hold a large ocean beneath its frozen surface.
Scientists have longed to draw samples from the lakes, but technical problems and environmental concerns have slowed their progress. Now, the Russian team expects to reach its quarry, Lake Vostok, by February 2011. The Americans and British will follow several years later with forays into lakes with different hydrological and geological characteristics (see graphic).
"Over the next few years we'll be able to explore a continental-scale ecosystem that has never before been sampled," says Robin Bell, a senior researcher at Columbia University's Lamont-Doherty Earth Observatory in Palisades, N.Y. "This is a madly exciting endeavor."
Lake Vostok is the best known and largest of the subglacial lakes, measuring roughly the size of Lake Ontario. Buried beneath almost 4,000 meters of ice in eastern Antarctica, the lake is thought to be 35 million years old and could host ancient microbial life.
Russian drillers had planned to penetrate the lake in the 2008-09 Antarctic field season, but their drill got stuck 80 meters above the lake surface. All technical problems have been resolved during the past field season, says Valery Lukin, director of the Russian Antarctic program, who spoke at the meeting, held by the American Geophysical Union in Baltimore, Maryland.
Some researchers worry that a Russian success could come at the cost of biological and chemical contamination of the pristine waters. "Let's hope they don't spoil the lake," says Robert Bindschadler, a glaciologist at NASA's Goddard Space Flight Center in Greenbelt, Md.
Lukin says that his country's team has come up with plans to safeguard Lake Vostok. The team will cut through the ice using a heated drill, with non-toxic silicone oil serving as the lubricating fluid. It will also explore the lake in stages; at first it will only suck up a water sample before allowing the bottom of the hole to refreeze. Plans for lowering instruments into the lake to explore the bottom sediment will be postponed until an extra environmental assessment has been completed.
The Antarctic Treaty's committee for environmental protection is expected to approve the Russian plans in October, although there is no official requirement for the team to wait until then. "The Russians are trying very hard to do it right, and that means a lot," says Bell.
At the meeting, U.S. and British researchers described their longer-term plans for exploring subglacial lakes on the opposite side of the pole. Lake Ellsworth, a relatively small lake in western Antarctica, is the target for researchers from the British Antarctic Survey. And over the next two field seasons, US researchers will conduct radar surveys from the surface to study Lake Whillans near Antarctica's Ross Ice Shelf, says Ross Powell, a geologist at Northern Illinois University in DeKalb. The US$20-million Whillans Ice Stream Subglacial Access Research Drilling (WISSARD) project, which Powell oversees, plans to drill into the lake during the 2012-13 field season.
Lake Whillans has a subsurface connection with the ocean beneath the ice shelf, making it more dynamic than isolated lakes such as Vostok. "We know that the lake surface is constantly falling and rising, and we assume the lake is occasionally draining and refilling completely," says Powell.
The ebb and flow of lakes such as Whillans are thought to influence the movement of the overlying ice sheet. The WISSARD team will study processes at the interface of ice and water that affect the movement.
With so many drilling projects, "it's like going fishing in the Everglades, in the Rocky Mountains and in Northern Canada", says Bell. "The catch will be very different and we're going to learn a lot."