Alberta student discovers salty Nunavut lakes under 700 metres of ice, a first for our planet

The extremely salty subglacial lakes in Nunavut are the first ever discovered on Earth, and could give us insight into life on other planets

Credit: KEVIN TUONG / FOR STARMETRO

 

Call it an ice surprise.

A University of Alberta grad student made an unexpected discovery studying an ice cap in the Canadian Arctic last spring that could provide clues about life beyond Earth.

PhD student Anja Rutishauser was using radar to study bedrock conditions underneath the Devon Ice Cap in Nunavut, a remote Arctic glacier on Devon Island, the largest uninhabited island in the world.

Underneath the 550 to 750 metres of ice was something that seemed impossible: water.

“We were super surprised when the radar data showed up that there should be liquid water,” Rutishauser said.

“It was very confusing, because it was supposed to be about -10 C there.”

It turns out the two bodies of water, each stretching several square kilometres, are isolated hypersaline — extremely salty — subglacial lakes.

They are believed to be the first in the world.

The water is four times saltier than seawater, which allows it to stay in liquid form.

“Only once we started to see the big picture and started to put the pieces together and understand that these subglacial lakes contain salty water, so the salt depresses the freezing point,” Rutishauser said. “So then it started to make sense.”

Rutishauser was studying data acquired by NASA and the University of Texas Institute for Geophysics using electromagnetic waves when she made the discovery.

The waves are sent into the ice and analyzed as they’re reflected back, essentially allowing researchers to see through the ice.

U of A glaciologist Martin Sharp and other scientists tested Rutishauser’s hypothesis, and on Wednesday the finding was published in the peer-reviewed journal Science Advances.

While there are more than 400 known subglacial lakes on Earth, all the others are believed to contain fresh water, rather than the hypersaline water that comes from salt-bearing geologic outcrops under the ice on Devon Island.

And although the lakes don’t quite resemble anything else on Earth, they might have relatives on one of Jupiter’s moons.

Rutishauser explained that they could serve as a terrestrial analog for Europa, which has similar conditions of salty liquid water underneath an ice shell.

“If we can explore the Devon subglacial lakes in terms of life, we can maybe better understand what are the possibilities and limitations of life in such extreme environments – not only on earth, but also on other planetary bodies,” she said.

The lakes could house microbial life, but it will probably be several years before scientists can say for sure.

Rutishauser and her colleagues are partnering with the W. Garfield Weston Foundation to do a more detailed geophysical survey over the Devon Ice Cap this spring.

Ultimately, they want to get through the ice and fish for life.

“It’s kind of our long-term mission to drill into those lakes and collect a sample,” Rutishauser said.

“It’s not very straightforward. And it has to be super clean drilling so we don’t contaminate anything. So it would be a long-term project, maybe five to seven years from now.”

Source :

Toronto Star

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