Scientists stumble upon super-salty lakes beneath Nunavut glaciers
Unusual discovery may offer insights into extraterrestrial life
Researchers studying Nunavut’s Devon Ice Cap have made a surprising discovery: beneath more than half a kilometre of ice lie two super-salty lakes.
They’re the first lakes of this kind to be found beneath glaciers. And scientists hope the unusual conditions created in these water bodies may give us a better idea of whether life can exist on other planets.
Researchers made the discovery using aircraft-mounted ground-penetrating radar, which essentially allows them to see through the glacier by bouncing electromagnetic waves through the ice and back. Their findings were recently published in the journal Science Advances.
“We weren’t looking for subglacial lakes,” Anja Rutishauser, a PhD student at the University of Alberta, said in a news release issued by the university. “The ice is frozen to the ground underneath that part of the Devon Ice Cap, so we didn’t expect to find liquid water.”
Instead, Rutishauser hoped to map the bedrock beneath the ice cap by analysing the data from airborne radar studies done by NASA and the University of Texas Institute for Geophysics.
“We saw these radar signatures telling us there’s water, but we thought it was impossible that there could be liquid water underneath this ice, where it is below -10C,” said Rutishauser.
The explanation that researchers hit on is that these lakes must be salty enough to withstand freezing at this temperature. That would make them four to five times saltier than seawater.
There are more than 400 known subglacial lakes in the world, but these are the first to be found in Canada. And they’re the only ones in the world known to be super-salty. Researchers believe this saltiness comes from salt-bearing outcrops beneath the ice—and they say there are likely other super-salty lakes hiding beneath some of Nunavut’s other glaciers.
What’s more, researchers say the two lakes—which measure eight and five kilometres squared—could be useful stand-ins for the icy moons in our solar system. “We think they can serve as a good analogue for Europa, one of Jupiter’s icy moons, which has similar conditions of salty liquid water underneath—and maybe within—an ice shell,” said Rutishauser.
“If there is microbial life in these lakes, it has likely been under the ice for at least 120,000 years, so it likely evolved in isolation. If we can collect a sample of the water, we may determine whether microbial life exists, how it evolved, and how it continues to live in this cold environment with no connection to the atmosphere.”
Rutishauser collaborated with her PhD supervisor, University of Alberta glaciologist Martin Sharp, and University of Texas geophysicist Don Blankenship and others from the University of Texas at Austin, Montana State University, Stanford University and the Scott Polar Research Institute for the study.
Rutishauser and her colleagues are now working with The W. Garfield Weston Foundation to do a more detailed airborne geophysical survey over the Devon Ice Cap this spring to learn more about the subglacial lakes.