Scientists discover first subglacial lakes in Canadian Arctic
Super salty water beneath ice may be analogue for habitat for life on other planets
Scientists have discovered two lakes below nearly half a mile of ice in the Canadian Arctic. While hundreds of freshwater lakes have been found under ice in other parts of the world, this is the first time researchers have documented subglacial lakes of water even saltier than the sea.
“We weren’t looking for subglacial lakes. The ice is frozen to the ground underneath that part of the Devon Ice Cap, so we didn’t expect to find liquid water,” said Anja Rutishauser, PhD student at the University of Alberta, who made the discovery while studying radar data from NASA and The University of Texas Institute for Geophysics (UTIG) to describe the bedrock conditions underneath the Devon Ice Cap.
Radar measurements are based on electromagnetic waves that are sent through the ice and reflected back at contrasts in the subsurface materials, essentially allowing scientists to see through the ice. “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 -10 C.”
While there are more than 400 known subglacial lakes in the world, concentrated primarily in Antarctica with a few in Greenland, these are the first in the Canadian Arctic. And unlike all the others — which are believed to be freshwater — these two consist of hypersaline water. Rutishauser explained the source of the salinity stems from salt-bearing geologic outcrops underneath the ice.
Rutishauser collaborated with University of Alberta glaciologist Martin Sharp, as well as geophysicists Dustin Schroeder from Stanford University's School of Earth, Energy & Environmental Science, and scientists from University of Texas at Austin, Montana State University, and the Scott Polar Research Institute to test her hypothesis. The bodies of water — roughly five and three miles squared, respectively — exist at temperatures below freezing and are not connected to any marine water sources or surface meltwater inputs, but rather are hypersaline, containing water four to five times saltier than seawater, which allows the water to remain liquid at these cold temperatures.
Implications for life beyond Earth
"This project was an ideal natural laboratory to push the limits on radar analysis techniques we've been developing to study both Earth's ice sheets and the icy moons of Jupiter. These lakes were smaller, saltier, and colder than the subglacial lakes we typically observe with ice penetrating radar on Earth. So, from a geophysical perspective they're already very alien," said Schroeder.
These newly discovered lakes are also potential habitats for microbial life and may assist scientists in the search for life beyond earth. Though all subglacial lakes are good analogues for life beyond Earth, the hypersaline nature of the Devon lakes makes them particularly tantalizing analogues for an icy moon of Jupiter.
“We think they can serve as a good analogue for Europa, one of Jupiter’s icy moons, which has similar conditions of liquid water underneath — and maybe within — an ice shell,” said Rutishauser. “If there is microbial life in these lakes, it has been under ice for at least 12,000 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, who plans to start a postdoctoral fellowship in the fall at the University of Texas at Austin, along with Schroeder and other colleagues are now in discussions with a private foundation to fund an airborne geophysical survey over the Devon Ice Cap this spring to derive more information about the lakes.
Rutishauser believes that similar salty rock outcrops occur underneath other Canadian Arctic ice caps. “Although the Devon hypersaline subglacial lakes are very unique discoveries, we may find networks of brine-rich subglacial water systems elsewhere in the Canadian Arctic.”
This research was supported by funds from the Natural Sciences and Engineering Research Council of Canada, Alberta Innovates Technology Futures, the CRYSYS Program (Environment Canada), the G. Unger Vetlesen Foundation, NASA, NSF and the UK Natural Environment Research Council. “Discovery of a hypersaline subglacial lake complex beneath Devon Ice Cap, Canadian Arctic” was published in the April 11 edition of Science Advances.