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Lakes beneath Greenland's Ice Sheet are much more common than previously assumed, say scientists who recently discovered 56 new subglacial lakes.
Only four had been detected earlier. The new discovery takes the total number of lakes up to 60, according to study published in the Nature Communications journal.
The lakes ranging from 0.2-5.9 kilometres in length were found beneath relatively slow moving ice suggesting they can trap and store meltwater for long-term.
Thus, they plays an important role in rising global sea levels and are also important targets for studying evidence of extreme life, the researchers said.
“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,” said Stephen J Livingstone of University of Sheffield.
Subglacial lakes are bodies of water that form beneath ice masses when meltwater generated from a number of sources, including the Earth's geothermal heat, becomes trapped due to variations in the ice’s thickness or in depressions.
However, rising temperatures are likely to lead the formation of lakes and streams at higher elevations. Water from these will make its way to the bed, causing the subglacial lakes to drain.
Researchers from the Universities of Lancaster, Sheffield and Stanford analysed more than 500,000 km of airborne radio echo sounding data and identified 54 subglacial lakes. Another two were discovered using ice-surface elevation changes.
Under the Antarctic's Ice Sheet, on the opposite pole, more than 400 subglacial lakes have been detected. These range in size from water bodies less than 1 km to approximately 250 km in length.
While much has been known of these Antarctic subglacial lakes, which has been known to fill, drain and cause overlying ice to flow quicker, little was known about Greenland's subglacial lake distribution and behaviour.
"This study has for the first time allowed us to start to build up a picture of where lakes form under the Greenland Ice Sheet," said lead author Jade Bowling of the Lancaster Environment Centre, Lancaster University.
"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 added.