Greenlands's First Known Subglacial Lakes Revealed

New research published in the journal Geophysical Research Letters details the first subglacial lakes to be identified in Greenland.

Two lakes lie about 800 meters below the Greenland Ice Sheet according to researchers at the Scott Polar Research Institute (SPRI) at the University of Cambridge. The area of the two lakes are between 8 and 10 kilometers squared, but at one point the bodies of water may have been up to three times their current size.

The discovery of the lakes will help researchers better understand how Greenland's ice sheet will respond to changing environmental conditions, as the subglacial lakes are likely to influence the flow of the ice sheet and impact global sea level change.

Steven Palmer, formerly of SPRI and now with the University of Exeter, led the research.

"Our results show that subglacial lakes exist in Greenland, and that they form an important part of the ice sheet's plumbing system. Because the way in which water moves beneath ice sheets strongly affects ice flow speeds, improved understanding of these lakes will allow us to predict more accurately how the ice sheet will respond to anticipated future warming," Palmer said.

The structure of the Greenland subglacial lakes is unusual compared to similar lakes detected beneath the Antarctic ice sheets, suggesting that the bodies of water formed in different manners.

The researchers suspect that, unlike in Antarctica, where surface temperatures remain below freezing all year, the Greenland lakes are likely fed by melting surface water draining through cracks in the ice overhead. Another theory is that nearby surface lakes may resupply the subglacial lake during warmer months.

The researchers suggest that this open, surface-connected structure makes the Greenland lakes different from Antarctic lakes, which are typically isolated ecosystems.

While more than 400 subglacial lakes have been detected in Antarctica, these two in Greenland are the first of their kind to be detected, the researchers said in a statement, adding that the relatively steeper ice surface on Greenland has been used to explain a lack of subglacial lakes on the landmass.

Lower temperatures on Greenland make for thinner ice, which prevents the insulating effect that takes place in subglacial lakes beneath the colder ice sheets of Antarctica.

"This means that any lakes that may have previously existed would have frozen relatively quickly. The thicker Antarctic ice can act like an insulating blanket, preventing the freezing of water trapped underneath the surface," the University of Cambridge said in a statement.

"As many surface melt-water lakes form each summer around the Greenland ice sheet, the possibility exists that similar subglacial lakes may be found elsewhere in Greenland. The way in which water flows beneath the ice sheet strongly influences the speed of ice flow, so the existence of other lakes will have implications for the future of the ice sheet."