How the surprise discovery of lakes under Arctic glaciers could help the search for life on Mars

The possibility of a subsurface lake on Mars raises intriguing questions about hidden lakes in the Canadian Arctic.

By Dermot Cole - September 3, 2018
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The headlines in late July conveyed some surprising findings from the Red Planet.

Scientists using radar observations believe they’ve found a 12-mile-wide saltwater lake that about one mile below the southern ice cap on Mars.

The lake is about three feet deep, according to data gathered from a European spacecraft in Mars orbit.

“We discovered water on Mars,” Italian scientist Roberto Orosei said at the time.

The biggest tipoff was that the radar echoes from below the Martian ice were stronger than those from the surface, a pattern that has been also seen on Earth.

For Anja Rutishauser, a doctoral student in glaciology at the University of Alberta, the possibility of a subsurface Martian lake raises intriguing questions about hidden lakes much closer to home.

Rutishauser was the lead author of a study published earlier this year about the discovery of two saltwater lakes on Devon Island in Nunavut, high in the Canadian Arctic.

Using techniques similar to those employed to examine Mars, Rutishauser and her co-authors analyzed radar data to find two lakes accidentally discovered about 550 to 750 yards beneath the Devon Ice Cap.

Before this study, researchers had believed that the Devon Ice Cap was solid to the bottom.

Rutishauser said they had not expected to find liquid water there because of the cold temperatures, but salt provides the most likely explanation.

“The radar reflected signal is much stronger when liquid water is present underneath the ice,” she said.

The biggest similarity with the Martian lake is that both places appear to have liquid salty water at temperatures well below the freezing point of freshwater, she said.

The water chemistry is probably different, but the salt likely originated in the rocks beneath the lakes.

The Devon Ice Cap lakes, which are under great pressure from the ice above, are about four times as salty as that in the Atlantic and Pacific oceans, she said.

More than 400 subglacial lakes have been found in Antarctica and Greenland, but those contain fresh water, kept from freezing by friction, pressure, insulation and heat from below ground.

The Devon Island subglacial lakes are the first in which water has been found with high salt content.

“These subglacial lakes and their surrounding environments are very different from those reported in Antarctica and Greenland,” the researchers said.

They are in mountainous terrain, “exist at temperatures well below the pressure-melting point, do not receive surface meltwater input, and likely consist of hypersaline water derived from dissolution of a surrounding salt-bearing geological formation.”

Direct sampling of the water is out of reach for the moment, both on Mars and Devon Island, but Rutishauser hopes that the Arctic lakes can be inspected more closely in years to come.

“Drilling into these subglacial lakes would be quite challenging due to the cold water temperatures and high salinity, but I believe it is possible,” said Rutishauser.

In June, Rutishauser and others collaborated with the W. Garfield Weston Foundation to do a detailed airborne survey of the area.

“This dataset will help us get a better understanding of the lakes, including their hydrological and geological contexts, and will lay the ground for future efforts such as drilling and sampling,” she said.

It is an open question as to whether the water on Devon Island may contain life, she said.

“However, microbial life has been found in numerous subglacial aquatic environments in both fresh and saline water, which shows life adapt to such extreme conditions,” she said.

“If life exists in these lakes, it could have evolved in isolation since the area was last overridden by glacier ice, which was at least 120,000 years ago,” the researchers said.

Learning more  about the Devon Ice Cap lakes will lead to a better understanding of life not only on Earth, but also perhaps on Mars and elsewhere in the universe.

The Arctic lakes make “compelling targets for future exploration,” the researchers said.

Columnist Dermot Cole can be reached at [email protected].