Environments with the power to unlock the secrets of other worlds have been found several hundred meters beneath the ice of the Canadian Arctic. A joint study published last month in Science Advances predicted the presence of two hypersaline subglacial lakes on either side of the east-west ice divide of the Devon Ice Cap, an ice cap located in Nunavut, Canada, known for its rugged terrain of both mountain ridges and bedrock troughs. These are not only the first subglacial lakes to be found in the Canadian Arctic but also the first hypersaline subglacial lakes reported to date, each estimated to be around 5 and 8.3 square kilometers.
The lakes, which are described as “unprecedented” in the study, are of great interest to researchers for their unique characteristics: both are hypersaline and spatially isolated. This isolation from outside influences may reach back 120,000 years ago, when the lakes were covered by glacial ice.
The lakes could represent significant microbial habitats, which could be used as analogs to study the conditions for potential life on other planets. Specifically, the study states that these lakes could represent similar environments to the potential brine bodies within Europa’s ice shell or Martian polar ice caps.
“Because these subglacial systems are isolated for tens of thousands of years, they are excellent candidates to explore life processes in extreme conditions,” states Alexandre Anesio, a professor and researcher at the University of Bristol who studies the biogeochemistry of the cryosphere. He sees this opportunity as “one of the best ways to explore the limits of life on other planets.”
The newfound potential of these lakes came as a shock, Anja Rutishauser, one of the study’s researchers, told GlacierHub. “The original research goal was to better understand these basal conditions of Devon Ice Cap, as they largely affect ice dynamics and how ice flow might change under future climatic conditions. We expected to find subglacial water signatures in the faster-flowing marine-terminating outlet glaciers, but certainly not in the center of Devon Ice Cap.”Rutishauser added that the ice cap was expected to have ice frozen to the ground, not liquid water or entire subglacial lakes.
The discovery was made when the researchers analyzed radio-echo sounding measurement data. Models further analyzed the basal ice temperature. It measured 10.5 degrees Celsius, which led to the conclusion that the hypersalinity was significantly depressing the freezing point temperature. Further, the study found that this is in “agreement with surrounding geology, situated within an evaporite-rich sediment unit containing a bedded salt sequence,” the likely source for the salt. The exact origins of the subglacial lakes and the processes that formed them remain unclear, but similar bodies can offer clues to the specifics of the Canadian lakes.
According to the study, Taylor Glacier in Antarctica contains the most comparable subglacial fluid to the Canadian lakes, with similar temperature and salinity measurements. However, it is sourced from ancient marine water and not spatially isolated. Taylor Glacier’s outflows have been found to have active microbial communities, which leads researchers to believe the same is possible in the Devon Ice Cap.
Many subglacial lakes in Antarctica and Greenland share other similarities with the Canadian lakes, further bolstering the study’s evidence. “Almost all the effort on subglacial lake exploration is concentrated in Antarctica, but this study reveals that there are other excellent locations for subglacial lake exploration,” according to Anesio. However, he believes further exploration is no trivial task considering the engineering challenge to drill cleanly into a subglacial lake without the risk of contaminating it. “However, it is certainly worth a try,” he said.
This is precisely how the researchers plan to follow up on their unprecedented discovery. “Our long-term vision is to cleanly access these lakes in order to derive if life exists,” added Rutishauser.
For now, Rutishauser said the research team is partnering with the W. Garfield Weston Foundation this spring to perform a more detailed aerogeophysical survey over Devon Ice Cap to derive more information about the lakes, including their hydrological and geological contexts.