To understand the bedrock under Devon Ice Cap, one of largest in the Canadian Arctic, PhD student Anja Rutishauser poured through radar data that she hoped would reveal a better picture.
But instead of finding solid ground, Rutishauser found liquid water.
The University of Alberta student found two super-salty lakes underneath the Canadian Arctic, located nearly a half a mile below the ice, Josh Gabbatiss reports for The Independent. And the discovery could provide insight into possible extraterrestrial life.
According to a press release, NASA and The University of Texas Institute for Geophysics (UTIG) collected the radar data by sending electromagnetic waves through the ice and then watching what bounced back. This allows scientists to essentially see what’s happening below the frosty surface. And the data hinted at the presence of a subglacial lake.
There are around 400 known subglacial lakes on Earth, but they are all believed to be freshwater or connected to a marine source, according to the press release. These lakes, mostly found in Greenland and Antarctica, are created by melting at the base of the ice. As Mary Halton reports for BBC News, heat rises from the bedrock but is insulated by a thick ice sheet, creating the perfect conditions for a subglacial lake.
But in the case of the Canadian ice sheet, the ice is not thick enough to insulate the heat and create a pocket of water.
"The ice is frozen to the ground underneath that part of the Devon Ice Cap, so we didn't expect to find liquid water," Rutishauser says in a statement. "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 -10C."
How could water stay liquid at such extremely cold temperatures? The bodies of water are not connected to other sources of water, so the scientists think the answer is salt.
The salt from rocks beneath the ice made the subglacial lakes four to five times saltier than seawater, or hypersaline. This saltiness allows the lake to stay liquid at temperatures well below the freezing point of pure water. It works the same way as salting your sidewalks in the winter to keep them from frosting over.
The lakes are thought to be the first isolated hypersaline subglacial lakes in the world, as detailed in the journal Science Advances. "I did the analysis multiple times, because I was, like, 'Can I really trust this?'" Rutishauser tells CBC News’ Kyle Muzyka. “Those lakes are super unique, and worldwide and that's very exciting.”
What's more, the conditions of the hyper-salty subglacial lakes are surprisingly similar to those found on Europa, one of Jupiter's many moons. Scientists think the new discovery may provide some insight into possible life there. That’s because, despite their darkness, isolation and cold conditions, subglacial lakes have been known to host microbial life, Rutishauser says in the press release.
As Gabbatiss writes, Europa is often considered to be one of scientists’ best chances at finding extraterrestrial life. Previous research suggests that the moon likely harbors a vast amount of water under its icy surface—and possible underwater volcanic activity. This has triggered speculation that the world might harbor life, perhaps similar to Earth's hydrothermal vents.
Rutishauser soon plans to collect samples of the water by drilling to measure the lakes’ salt levels and look for signs of microbial life there. If she finds it, the discovery could help researchers better understand what life on Europa would look like.
"If there is microbial life in these lakes, it has likely been under the ice for at least 120,000 years, so it likely evolved in isolation,” she says in the statement. “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."
The likelihood that life exists in these hypersaline subglacial systems is high, Alison Murray of Nevada's Desert Research Institute tells Halton. Though the temperatures might limit whatever biological activity is found.
But there’s still work to be done. The team plans to complete a geophysical survey of the Devon Ice Cap this spring that should also answer questions about how the lakes formed and whether more subglacial lakes exist nearby.