Researchers have identified 85 previously unknown subglacial lakes beneath Antarctica’s thick ice, raising the count of known active lakes to 231.

Published in the journal Nature Communications, the study highlights the significance of these hidden lakes in influencing glacier movement and the stability of the Antarctic Ice Sheet, with implications for future sea level rise.

The new lakes are located several kilometres beneath the surface near the South Pole. By analysing a decade of height data from the European Space Agency’s CryoSat satellite, scientists detected subtle changes as the lakes filled and drained, offering rare insight into Antarctica’s concealed hydrological systems.

The research also uncovered five networks of interconnected subglacial lakes and new drainage pathways.

Subglacial lakes are challenging to study because they are buried under hundreds of metres of ice. Sally Wilson, lead author and doctoral researcher at the University of Leeds, explained, “It is incredibly difficult to observe subglacial lake filling and draining events in these conditions, especially since they take several months or years. Only 36 complete cycles had been observed worldwide before our study. We observed 12 more, bringing the total to 48.”

Satellite observations have been crucial in mapping these lakes. The CryoSat mission, launched in 2010, has recorded changes in ice thickness and height over Antarctica, using radar altimetry to track minute surface shifts linked to activity beneath.

Anna Hogg, co-author and Professor at the University of Leeds, said, “It was fascinating to discover that the subglacial lake areas can change during different filling or draining cycles.

This shows that Antarctic subglacial hydrology is much more dynamic than previously thought, so we must continue to monitor these lakes as they evolve in the future.”

The research addresses gaps in understanding water flows beneath the ice sheet. “The numerical models we currently use to project the contribution of entire ice sheets to sea level rise do not include subglacial hydrology. These new datasets of subglacial lake locations and timeseries of change will help us understand the processes driving water flow beneath Antarctica,” said Sally Wilson.

Subglacial lakes form as meltwater accumulates due to geothermal heat and friction from ice sliding over bedrock. The periodic filling and draining of these lakes can reduce friction, causing ice to move more rapidly towards the ocean and potentially affecting global sea levels.

Many subglacial lakes are stable, but active lakes undergo cyclical changes. The largest, Lake Vostok, contains enough water to fill the Grand Canyon, but remains stable under the East Antarctic Ice Sheet.

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