More than 2 miles beneath the coldest spot on Earth, Russians scientists have finally reached the surface of Antarctica's Lake Vostok. The team confirmed today it has finally pierced the upper reaches of the lake, which is roughly the size of Lake Ontario and has been sealed off from the atmosphere for 15 to 34 million years. It's the first time anybody has drilled into one of Antarctica's roughly 280 subglacial lakes, and scientists are hoping the lake water might reveal heretofore unknown forms of life.
But getting there wasn't easy. Montana State University researcher John Priscu, who communicates regularly with the Russian group, says the Russians have been stalled for several years figuring out how to drill into the lake without contaminating it. According to Priscu and the Russian team's statement, the researchers completed the final steps of drilling using a technique to depressurize the final length of borehole so that lake water would rush up into it. That also prevents kerosene and Freon from leaking downward; besides contaminating the water, those chemicals could circulate throughout the borehole to keep it from freezing shut, which is what the drillers want.
The Russian statement, released by the head of the Russian Antarctic Expedition, Valery Lukin, said the drill made contact with the lake at a depth of 12,366 feet. Water then rushed 100 to 130 feet up the borehole, according to the team's measurements, where it should then freeze and prevent leakage, Priscu says. The Russian team has actually already left Antarctica because the end of summer there is fast approaching and temperatures have plunged to nearly -50 Fahrenheit. In December, when the next Antarctic summer begins, the team will return to take core samples of the ice and look for signs of life.
Drillers first bored into the ice sheet at Vostok more than 20 years ago to take ice cores, an extremely valuable source of information about the composition of our atmosphere over the last 400,000 years. (For example, analysis of the concentrations of carbon dioxide and oxygen isotopes within ice-bound bubbles has shown a link between atmospheric carbon and global temperatures.) Back then, the Russian began drilling with a traditional mechanical drill, and kept the hole open year-round by circulating drilling fluids throughout its length. But in the late 1990s, researchers realized the pristine subglacial Lake Vostok, isolated for millions of years, was right beneath their feet, according to Robin Bell, a researcher at the Lamont-Doherty Earth Observatory at Columbia University in New York. The methods that Russian scientists had been using to extract ice cores, which are similar to those used to drill for oil, are effective but messy. So, since the 1990s, Russian scientists have been drilling toward the lake while trying to figure out how to reach it without contaminating it.
The Russians may have gotten to a subglacial lake first, but they've got company. Teams from the United Kingdom and United States are close behind them, poised to make their own breakthroughs into other lakes on Antarctica. The British have been planning for several years to drill into Lake Ellsworth, a subglacial lake toward the west of the continent, and they are set to begin drilling in late 2012. David Blake, head of technology and engineering for the team said they've already manufactured all the parts to get into the lake and get a good look at it.
In some ways the Americans and British may have it easier than the Russians. For example, Blake says, their drill is designed to be much cleaner than the one used by the Russians; rather than a mechanical system, the British team will plow through the ice by sending pressurized—and sterilized—hot water squeezed through a 2-mile-long hose to melt a path through the roughly 12,000 feet of ice above the lake. The team will then lower cables with a series of instruments to measure the lake's temperature, pressure, and chemistry, as well as snap photos and take samples of water and sediment. But they must do it quickly; Blake calculates the hole will only stay open for little over 24 hours. All the equipment has already been sterilized and sealed. It's ready to go when summer returns to the icy continent late in 2012.
An artist's representation of the aquatic system scientists believe is buried beneath the Antarctic ice sheet. Credit: Zina Deretsky / NSF
The Americans have a similar plan to drill into Lake Whillans, close to the Ross Ice Shelf. Unlike the other lakes, though, Whillans likely has a one-way sub-surface connection to the sea, and it also swells and shrinks as the ice sheet above it moves in concert with the seasonal movements of glaciers near the ocean. Its underwater connections, proximity to the sea, and seasonal variability make it more dynamic than the other lakes. Chuck Kennicutt, Texas A&M University researcher and president of the Scientific Committee on Antarctic Research, which oversees much of the research conducted on the continent, says looking into this lake should provide a glimpse of yet another kind of subglacial environment. Frank Rack, an engineer at the University of Nebraska-Lincoln, designed the team's hot water drill. "It's basically like one of those pressurized sprayers you see at a car wash," Priscu says, "except much bigger." The system also has several small filters and UV emitters so that when the 197 F water comes out, it won't contaminate the subglacial gem.
Once the hole is drilled, the Americans will then lower a suite of instruments similar to the Brits' to get a physical picture of Whillans and take water samples and pictures. They will also use a filter that circulates water, trapping any DNA or microbes present in the water. Small metal tubes will be dropped to the bottom to take samples of sediment, which should provide vital clues to the biology of the lake, as well as its paleoclimate and formation. All sensors will be sterilized before being submerged.
The U.S. team also hoped to introduce the Sub-Ice Rover, a 27.5-foot underwater robot from Northern Illinois University that can be retracted to fit through a borehole before unfolding and going to work on the other end. Unfortunately, Kennicutt says, the funding for that project fell through, but he hopes it will be able to go to Antarctica the next year. Researchers also plan to introduce permanent monitors in the future, if funding comes through, to provide a continuous look at the lake and any life it may harbor and likely other robotic explorers. For now, though, the Americans will be limited to about a week, the length of time the hole is predicted to stay open before inevitably freezing shut.
While the Russians have beat the rest of the world to Vostok, it may be the Brits or the Americans who actually find the first indisputable evidence of life within these isolated environments, since they will begin sampling liquid water around the same time the Russians will retrieve their ice cores. Regardless of who's first, though, finding life here would be hugely important. For one thing, it would give scientists reason to believe life could survive beyond Earth, such as within the icy moons of Jupiter, whose environments are thought to be similar to that of these Antarctic lakes.
Although many researchers expect to find life in these dark and isolated waters, Priscu is sure that it will happen. He published a controversial 1999 study in the journal Science suggesting the presence of DNA in Lake Vostok, and the discovery of microbes in environments that surround these lakes, such as subglacial sediments and the glacial ice itself. "I think it would be the exception, as opposed to the rule, if we don't find bugs down there," Priscu says. "It's our planet's biggest wetland. I bet life isn't just eking it out down there, but thriving."