Scientists have discovered 85 "active" lakes buried beneath Antarctic ice.

The European Space Agency's Cryosat-2 satellite is monitoring subtle changes in ice sheet thickness in Antarctica and Greenland. (Image credit: ESA/AOES Medialab)

Scientists, using satellite data collected over a decade, have discovered 85 previously unknown lakes hidden beneath the Antarctic ice.

The researchers stated that the newly discovered lakes are “active,” meaning they periodically dry up and fill, changing size and shape over months and years. This subglacial activity affects the stability of glaciers and their movement across Antarctic bedrock, which, in turn, could affect global sea levels, the researchers noted.

“It was very exciting to find that the areas of subglacial lakes can vary with filling and draining cycles,” said study co-author Anna Hogg, a professor in the Department of Earth Observation at the University of Leeds (UK), in a statement from the European Space Agency (ESA). “This shows that Antarctica's subglacial hydrology is much more dynamic than previously thought, so we need to continue to monitor the evolution of these lakes in the future.”

You may like

Scientists have discovered long-lost giant rivers that flowed through Antarctica up to 80 million years ago.
'It was so unexpected': 90 billion litres of meltwater pierced the Greenland ice sheet in an unprecedented melt
Antarctic sea ice collapse linked to mysterious surge in ocean salt levels

Prior to this latest discovery, 146 active subglacial lakes were already known in Antarctica. The new study brings the total number of active lakes to 231 and expands scientists' understanding of when and how subglacial lakes drain and refill, said lead author Sally Wilson.

“Monitoring the filling and draining of subglacial lakes is incredibly challenging,” said Wilson, a doctoral student at the University of Leeds's Institute of Climate and Atmospheric Science. “Before our study, only 36 complete cycles—from the beginning of filling to the end of draining—had been recorded worldwide. We recorded another 12 complete filling and draining cycles, bringing the total to 48.”

Subglacial lakes are accumulations of meltwater that form when geothermal heat from the Earth's interior rises to the base of an ice sheet or when sufficient heat is generated by friction between ice and bedrock. Subglacial lakes can occasionally dry out periodically, creating a flow of water that lubricates the bottom of the ice sheet and facilitates its sliding over bedrock, accelerating the ice's movement toward the ocean.

For the study, the scientists analyzed data collected between 2010 and 2020 by the European Space Agency's Cryosat-2 satellite, which measures changes in the thickness of sea ice, glaciers, and ice sheets worldwide. Cryosat-2 is equipped with an instrument called a radar altimeter, which can detect small changes in the elevation of ice formations, including changes caused by runoff and the filling of lakes at the base of the ice.

The data revealed dozens of locations where the Antarctic ice sheet alternately sinks and rises slightly as meltwater drains and recharges subglacial lakes. The observations also revealed 25 lake groups and five previously unobserved subglacial lake networks with interconnected drainage and recharge cycles, the researchers wrote in a study published September 19 in the journal Nature Communications.

A map of Antarctica showing the locations of 85 recently discovered “active” subglacial lakes (red triangles). The pink area is where Cryosat-2 collected data between 2010 and 2020.

The results are important because they expand scientists' understanding of ice sheet dynamics and their impact on global sea levels, which could help researchers develop more accurate climate and Earth models. “The numerical models we currently use to predict the contribution of all ice sheets to sea level rise do not account for subglacial hydrology,” Wilson said. “These new datasets on the locations of subglacial lakes, their extent, and time series of changes will be used to deepen our understanding of the processes that control water flows beneath Antarctica.”