Life Found Deep Below Antarctic IceScience Monday, February 4th, 2013
Janet Raloff | ScienceNews
Cells containing DNA have emerged as the first evidence of life in a subglacial lake in West Antarctica. On January 28, a U.S. research team retrieved water from Lake Whillans, which sits 800 meters below the ice surface. The water hosted a surprising bounty of living cells.
The scientists collected three 10-liter water samples from the lake. Preliminary tests conducted in mobile labs show that the cells are actively using oxygen. It may take months for biologists to identify the microbes present.
A challenge was ruling out contamination as a source of the cells, says microbiologist Brent Christner of Louisiana State University in Baton Rouge, reached by satellite phone at a tent encampment at the drill site. Even glacial ice harbors low concentrations of microbes, “or their corpses,” so the researchers were concerned that cells in the lake samples could actually have come from the ice, Christner says.
He argues that the cells come from the lake. First, cell concentrations in water retrieved from the lake were on the order of 10,000 per milliliter, which is about 100 times higher than the cell count in meltwater from the drill hole. Second, that meltwater is roughly comparable chemically to distilled water. In contrast, mineral levels in the water from which Christner’s team isolated its cells are 100 times higher — equivalent to what’s present in the lake’s water.
“This is a big deal — and exciting,” says glaciologist Martin Siegert of the University of Bristol in England. The U.S. team’s drilling endeavor marks “the first clean access to a subglacial lake system.” Acquiring clean samples is imperative, he adds, to inspire confidence that any microbial finds truly come from the buried lakes…