A pair of massive subglacial lakes have been discovered underneath of the melting Greenland Ice Sheet by researchers from the Scott Polar Research Institute (SPRI) at the University of Cambridge. The lakes — located over 800 meters beneath surface of the ice sheet — are each around 8-10 km2 in size.
The new research was done by utilizing airborne radar measurements to peer underneath of the massive ice sheet. It’s currently thought that the behavior of subglacial lakes have a significant impact on the flow of ice sheets — thereby exercising a great impact on the rate of any potential sea level rise that we may experience in the near-future.
Lead author Dr Steven Palmer, formerly of SPRI and now at the University of Exeter, stated: “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.”
The University of Cambridge provides more:
The lakes are unusual compared with those detected beneath Antarctic ice sheets, suggesting that they formed in a different manner. The researchers propose that, unlike in Antarctica where surface temperatures remain below freezing all year round, the newly discovered lakes are most likely fed by melting surface water draining through cracks in the ice. A surface lake situated nearby may also replenish the subglacial lakes during warm summers. This means that the lakes are part of an open system and are connected to the surface, which is different from Antarctic lakes that are most often isolated ecosystems.
While nearly 400 lakes have been detected beneath the Antarctic ice sheets, these are the first to be identified in Greenland. The apparent absence of lakes in Greenland had previously been explained by the fact that steeper ice surface in Greenland leads to any water below the ice being ‘squeezed out’ to the margin. The ice in Greenland is also thinner than that in Antarctica, resulting in colder temperatures at the base of the ice sheet. 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 researchers speculate that there is a great possibility that there are other such meltwater lakes currently underneath of the ice sheet — the existence of such lakes will have great implications for the future of the ice sheet.
The new findings were just detailed in a paper published in the journal Geophysical Research Letters.
Image Credit: Greenland via Wikimedia CC