June 26 (UPI) -- Researchers have found an additional 56 lakes under the Greenland Ice Sheet, bringing the island's total number of subglacial lakes to 60.
Projecting ice loss in Greenland remains difficult, but studies suggest the island's glaciers are melting more rapidly than they were a few decades ago. As Greenland continues to melt, sea levels are expected to rise.
Understanding the movement of water beneath the ice sheet is vital for scientists trying to predict the ice sheet's future behavior.
Subglacial lakes form when meltwater becomes trapped and pools at the bottom of an ice sheet. Ice melted by the pressure of the thick, heavy icy above can supply the lakes with water, as can ice melted by Earth's geothermal heat or heat produced by the flow of the ice. Surface meltwater can also filter to the base of the ice sheets through crevices.
By more accurately mapping and tracking the changes of Greenland's subglacial lakes, scientists can gain a better understanding of how the island's ice sheet drains. A more detailed understanding of the ice sheet's drainage dynamics can help researchers better predict how the Greenland Ice Sheet will respond to climate change.
Scientists found 54 of the lakes by analyzing airborne radio echo sounding data, which provides a map of the bed of the ice sheet. Another two were identified by studying ice-surface elevation changes.
"Researchers have a good understanding of Antarctic subglacial lakes, which can fill and drain and cause overlying ice to flow quicker," Jade Bowling, PhD student at Lancaster University, said in a news release. "However, until now little was known about subglacial lake distribution and behavior beneath the Greenland Ice Sheet."
Thanks to the new research, published this week in the journal Nature Communications, scientists now have a better idea of where the ice sheet's meltwater pools.
"This is important for determining their influence on the wider subglacial hydrological system and ice-flow dynamics, and improving our understanding of the ice sheet's basal thermal state," Bowling said.
Though most of the lakes were found beneath slow moving ice on the periphery of the ice sheet's thicker, more stable interior, researchers suggest climate change could trigger melting at higher elevations in the future, triggering the formation of subglacial lakes beneath the heart of the Greenland Ice Sheet.
"The lakes we have identified tend to cluster in eastern Greenland where the bed is rough and can therefore readily trap and store meltwater and in northern Greenland, where we suggest the lakes indicate a patchwork of frozen and thawed bed conditions," said Stephen J. Livingstone, senior lecturer in physical geography at the University of Sheffield. "These lakes could provide important targets for direct exploration to look for evidence of extreme life and to sample the sediments deposited in the lake that preserve a record of environmental change."