Quirks & Quarks

Newly discovered salt lakes in Canadian Arctic help us understand Jupiter's moons

Scientists never expected to find two lakes under a glacier in below freezing temperatures.
A cold and windy spring night on the vast landscape of Devon Ice Cap — two subglacial lakes are lurking 750 metres below the surface. (Anja Rutishauser)

A surprise discovery

It was supposed to be a routine PhD. project to analyze the bedrock underneath the ice cap on Devon Island in Nunavut.

Instead, Anja Rutishauser, a PhD student from the University of Alberta was analyzing the radar data collected from recent aerial surveys and saw a distinct mirror-like reflection off the radar signals.

This is a tell-tale sign for liquid water. Except, it's under a glacier over half a kilometre thick in the furthest northern reaches of Canada where the ice never gets warmer than -13C. The liquid water simply shouldn't be there.

Only one explanation

There were two distinct lakes, one almost five square kilometres in area and the other over eight square kilometres and the team was convinced it had to be water.

There was only one explanation for the presence of liquid water at that temperature: it had to be salty, really salty.

The researchers propose that these hyper-saline lakes must be at least four times as salty as seawater to keep them liquid below freezing.

Another mystery emerged: where was the salt coming from? These lakes appear in the middle of the Devon ice cap nowhere near any sources of salt water or any water input.

The salt must be coming from the bedrock. Mineral halite was discovered nearby and the team suggests that this mineral runs right under the lakes and could be leaching salt and melting the ice above, similar to how rock salt works in the middle of a Canadian winter.

And this melting of the ice has probably been happening for tens of thousands of years to accumulate the amount of water in these large lakes. Yet, the lakes are completely isolated from the atmosphere and the rest of the world since the last ice age.

Alien world

The idea that super salty lakes can be buried under ice isn't new. The moon Europa that orbits Jupiter is thought to have lakes under its icy surface.

But these types of lakes are newly discovered here on Earth - which means that exploring the lakes right here in Canada may be a good analog for how to explore lakes on other worlds.

The University of Alberta group doesn't know if there is life inside the lakes, that will take years to determine but if there is, it will represent an ecosystem unlike any ever discovered on Earth and may be closer to alien life than we have ever come across.