Researchers have discovered two new subglacial lakes 800 meters beneath the Greenland Ice Sheet, which are spread across an area of 8-10 km.
A team of British researchers have identified two subglacial lakes 800 meters beneath the Greenland Ice Sheet. They are 8-10 km in size and can help researchers understand how the ice will respond to changing environmental conditions, according to a press release.
"Our results show that subglacial lakes exist in Greenland, and that they form an important part of the ice sheet's plumbing system," Lead author Dr Steven Palmer, formerly of SPRI and now at the University of Exeter said. "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."
Subglacial lakes are likely to influence the flow of the ice sheet, impacting global sea level changes. Researchers assume that the newly discovered lakes may have been three times larger than their current size at one point. They are also very different from the subglacial lakes detected beneath the Antarctic ice sheets, suggesting their formation process may have been different.
Unlike Antarctica where surface temperatures remain below freezing point all year long, these subglacial lakes were fed by melted ice water that seeped through cracks on the surface of the ice sheet. Researchers also speculate that a surface lake situated nearby may have also refilled the subglacial lakes during warm summers.
The following assumptions led to the conclusion that the newly discovered lakes were part of an open system and were connected to the surface, which is different from Antarctic lakes that are most often isolated ecosystems.
This is the first set of subglacial lakes discovered under the Greenland ice sheet, though more than 400 such lakes have been discovered in Antarctica. Up until now researchers believed that such lakes didn't exist in Greenland and supported their theory by suggesting that steeper ice surface in Greenland leads to any water below the ice being 'squeezed out' to the margin.
The Antarctica ice sheet is also thicker, which means that it acts like an insulin blanket, preventing the water present beneath the surface from freezing.
"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," the researchers concluded.
Findings of the study were published in Geophysical Research Letters.
