Web edition: January 28, 2013
At 5 a.m. local time today (January 28), U.S. researchers successfully completed boring a 30-centimeter-diameter hole through 800 meters of Antarctic ice, piercing into Lake Whillans. It’s one of a series of interconnected subglacial lakes that periodically fill and drain. Scientists estimate that the lake’s water, which flows beneath the Whillans Ice Stream, has not had contact with the atmosphere for untold millennia.
Research teams from Russia, the United Kingdom and United States have each spearheaded drilling efforts over the past few years to pierce and sample separate subglacial Antarctic lakes. Russian scientists reported last year piercing into Lake Vostok but has so far turned up no identifiable life. Those researchers are now working to analyze a new sample of ice recently retrieved from that drill project. Last month, the British team suspended its efforts for this summer season (which ends next month) to reach Lake Ellsworth.
The just-completed borehole into Lake Whillans “marks the first successful retrieval of clean whole samples from an Antarctic subglacial lake,” the U.S. team reported today. “Water and sediment samples returned to the surface are now being processed to answer seminal questions related to the structure and function of subglacial microbial life, climate history, and contemporary ice sheet dynamics.”
A research team led by Frank Rack, of the University of Nebraska, Lincoln, recently developed and field-tested the novel hot-water drill used to cut through the roughly half-mile-deep sheet of ice to reach Lake Whillans. “Over the whole Antarctic continent, there are more than 340 [subglacial] lakes,” he notes. “We selected this one because we know that it goes up and down, which means that the water underneath the ice sheet is periodically filling up the lake, then draining out again.”
Researchers have monitored this cycle through a rise and fall of the surface of that portion of the ice sheet covering the lake. Each cycle can last up to a decade, Rack says.
A video camera and series of sampling instruments will be periodically lowered down the borehole in the day or two available before this portal begins freezing shut again. “Lake Whillans has already presented surprises,” according to Doug Fox, a reporter embedded with the drill research team, which is camped out less than 400 miles from the South Pole. “For one, the lake has turned out to be only five or six feet deep — shallower than the 20 to 30 feet that people expected based on seismic measurements,” Fox reported in a blog on the Discover website.
When I met with the Lake Whillans research team, last month, they planned to begin analyses of retrieved water and sediment within minutes of it reaching the surface. A series of mobile research labs were recently hauled to the Lake Whillans drill site. At least one lab will be used to study the chemistry of the water. Another will focus on probing for signs of microbial life — chiefly bacteria and viruses.
Whillans Ice Stream Subglacial Access Research Drilling (WISSARD) home page. [Go to]
J. Raloff. Antarctic test of novel ice drill poised to begin. Science News blog. Dec. 15, 2012. [Go to]