Nestled in a steep fjord beneath three kilometers of Antarctic ice, the lost world of Lake Ellsworth has haunted Martin Siegert’s dreams ever since he got involved in subglacial research a dozen years ago. Finally, the time has come for him to explore its mysterious waters.
Next week, Siegert, a glaciologist at the University of Bristol, UK, packs his bags for the long journey to the opposite end of the world. Once he has reached the Rothera Research Station of the British Antarctic Survey (BAS) on an island off the Antarctic Peninsula, he and his science crew will fly about 1,000 kilometers into western Antarctica. On 5 December, the real work begins: drilling straight down through the ice to the pristine lake beneath. In its shadowy waters they hope to find forms of life that have not seen the light of day in millions of years (see ‘Trapped under ice’). And in the lake bed sediments, the team will search for records of the poorly understood history of the West Antarctic Ice Sheet, potentially revealing how the mighty glacier has waxed and waned over time.
Is Siegert excited? “This is the very pinnacle of the science I’ve been doing since the turn of the millennium,” he says. “Now guess if I’m excited.”
Almost 380 subglacial lakes have been discovered and mapped in Antarctica, and have been explored remotely with ice-penetrating radar, gravity measurements and seismic investigations (A. Wright and M. Siegert Antarctic Science http://doi.org/jsn; 2012). These ancient lakes, large and small, owe their existence to geothermal heat that melts the Antarctic ice from below. Gravity and ice pressure force the melt water to flow, and it collects in the hollows and valleys of the continent under the ice.
If all goes to plan, Lake Ellsworth will be the second such lake to be breached. In February, a Russian team penetrated Lake Vostok — the largest and deepest Antarctic lake — completing a project that was launched more than 20 years ago (see Nature 482, 287; 2012). And a third effort is about to begin: next week, a US drilling team will set out for McMurdo Station in Antarctica. In January, the researchers will move to their target — subglacial Lake Whillans, a small, shallow body of water close to the edge of the Ross Ice Shelf.
The quest to find exotic microbial life that may have evolved in or beneath these lakes is for many the most thrilling aspect of the research. Scientists have discovered a catalogue of bacteria elsewhere that mine their energy from rocks and minerals, and many assume that specialized microbes living in Antarctica’s hidden lakes might do the same.
“Life exists in extreme ecosystems, from the deep lithosphere to the high atmosphere,” says David Pearce, an environmental microbiologist with the BAS who will join the UK expedition. “I would be incredibly surprised if we get there and find no organisms at all.”
The Lake Vostok team found evidence that heat-loving bacteria may live in the bedrock surrounding that lake. The clues came from DNA in sediment that had become trapped in accretion ice — the lake water that freezes to the bottom of the massive glacier (S. A. Bulat et al. Adv. Space Res. 48, 697–701; 2011).
But the upper layers of the lake itself seem to be lifeless, reported Sergey Bulat, a microbiologist at the Petersburg Nuclear Physics Institute in Russia, at the 12th European Workshop on Astrobiology in Stockholm last month. No native microbes turned up in a preliminary analysis of lake water that had frozen onto the Russians’ drill bit, although the team will return to the site this season to collect more samples.