There is life in Lake Whillans. For millions of years, this small body of liquid water has lurked hundreds of meters below Antarctica's Ross Ice Shelf, sealed off from the outside world and the scientists who would explore its subglacial depths. Now, in a monumental first, a team of researchers led by Montana State University glaciologist John Priscu has bored a tunnel to Whillans and encountered life, making Priscu and his colleagues the first people in history to discover living organisms in the alien lakes at the bottom of the world.
I say "alien" because Lake Whillans — like the hundreds of other subglacial lakes and waterways entombed beneath Antarctica's assorted ice shelves — is thought to harbor conditions similar to those of Jupiter's moon Europa and Saturn's moon Enceladus. Hundreds of meters below the surface of Earth's southernmost continent, pressures soar to vitality-crushing levels. Nutrient availability is minimal. Sunlight is nonexistent. Antarctica's bygone repositories of liquid water have been isolated from the rest of the world for so long, under conditions so extreme, that evidence of life in any of the continent's subsurface reservoirs would bode well for our chances of discovering life on other worlds — to say nothing of the enormous boon such a discovery would be to biological research here on Earth.
Now, it appears we have that evidence.
"Lake Whillans definitely harbors life," said Priscu in a phone interview with Nature News's Quirin Schiermeier. "It appears that there lies a large wetland ecosystem under Antarctica's ice sheet, with an active microbiology."
Pictured above is the tunnel that Priscu and his colleagues had to drill in order to break through to the lake's surface last month, on the 28th of January. "What they found," writes Schiermeier, "was a body of water just 2 metres or so deep - much shallower than the 10–25 metres seismic surveys had suggested, although Priscu notes that the lake may well have deeper spots."
The team put a camera down the borehole to make sure that the borehole was wide enough for sampling instruments to be deployed and returned safely. It was, and over the next few days, the scientists collected some 30 litres of liquid lake water and eight sediment cores from the lake's bottom, each 60 centimetres long.
What precious stuff they had retrieved soon became clear under the on-site microscope. Both water and sediment contained an array of microbes that did not need sunlight to survive. The scientists counted about 1,000 bacteria per millilitre of lake water - roughly one-tenth the abundance of microbes in the oceans. In Petri dishes, the bacteria show a "really good growth rate", says Priscu.
Photographs like the one featured below, captured by cameras at the bottom of Lake Whillans, can't tell us much of anything about the genetic makeup of these microbes. That being said, the hypothesis that these organisms will represent some heretofore undescribed extremophiles, uniquely suited to their punishing local environment, is not an unreasonable one; and it's a hypothesis which, if confirmed, could make for some very intriguing lines of genetic investigation.
To that end, Priscu says he and his team will have to rely on DNA sequencing and other tests, preliminary rounds of which will take at least a month to perform. Followup studies will surely extend out for years to come.
"What we are all dying to find out now is, of course, ‘who's there' and ‘what's their life style'," he says.
Aren't we all.
Read more at Nature News and at links provided throughout the post. For more on the hunt to explore Antarctica's subglacial lakes, start by visiting here and here; Lake Whillams may be the first of Antarctica's subsurface pools to exhibit an active microbiology, but it's far from the first to have its surface breached.
Photos by Alberto Behar, JPL/ASUM