Discovery of a hypersaline subglacial lake complex beneath Devon Ice Cap, Canadian Arctic

Subglacial lakes are unique environments that, despite the extreme dark and cold conditions, have been shown to hostmicrobial life. Many subglacial lakes have been discovered beneath the ice sheets of Antarctica and Greenland, but no spatially isolated waterbodyhas been reported to be hypersaline.Weuse radio-echosoundingmeasurements toidentify twosubglacial lakes situated in bedrock troughs near the ice divide of Devon Ice Cap, Canadian Arctic. Modeled basal ice temperatures in the lake area are no higher than-10.5°C, suggesting that these lakes consist of hypersalinewater. This implication of hypersalinity is in agreement with the surrounding geology, which indicates that the subglacial lakes are situated within an evaporite-rich sediment unit containing a bedded salt sequence, which likely act as the solute source for the brine. Our results reveal the first evidence for subglacial lakes in the CanadianArctic and the first hypersaline subglacial lakes reported to date.We conclude that thesepreviouslyunknownhypersaline subglacial lakesmay represent significant andlargely isolatedmicrobial habitats, andare compelling analogs for potential ice-covered brine lakes and lenses on planetary bodies across the solar system.