Using a decade of satellite data, researchers have identified 85 previously unknown lakes several kilometres under the frozen surface surrounding the South Pole.
Hidden beneath the biggest ice mass on Earth, hundreds of subglacial lakes form a crucial part of Antarctica’s icy structure, affecting the movement and stability of glaciers, and consequentially influencing global sea level rise.
Thanks to a decade of data from the European Space Agency’s CryoSat-2 satellite, researchers led by Sally Wilson, a doctoral researcher at the University of Leeds, have increased the number of known active subglacial lakes below Antarctica by more than half to 231.
The research, published today in Nature Communications, is significant because active subglacial lakes, which drain and refill on a cyclical basis, offer a rare insight into what is happening kilometres below the ice surface, at the base of the ice sheet.
The research also identified new drainage pathways underneath the glaciers, including five interconnected lake networks.
Lead author of the study, Sally Wilson from the School of Earth and Environment at Leeds, explained that what we know about subglacial lakes and water flow is limited because they are buried under hundreds of metres of ice.
She said: “It is incredibly difficult to observe subglacial lake filling and draining events in these conditions, especially since they take several months or years to fill and drain.
“Only 36 complete cycles, from the start of subglacial filling through to the end of draining, had been observed worldwide before our study. We observed 12 more complete fill-drain events, bringing the total to 48.”
Study co-author Anna Hogg, Professor of Earth Observation at the University of Leeds, said, “it was fascinating to discover that the subglacial lake area’s 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.”
Sally explained that observations like these are vital to understanding the structural dynamics of ice sheets and how they affect the ocean around them.
She said: “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, extents, and timeseries of change, will be used to develop our understanding of the processes driving water flow beneath Antarctica.”
Martin Wearing, ESA Polar Science Cluster Coordinator, noted: “This research again demonstrates the importance of data from the CryoSat-2 mission to improve our understanding of polar regions and particularly the dynamics of ice sheets.
“The more we understand about the complex processes affecting the Antarctic Ice Sheet, including the flow of meltwater at the base of the ice sheet, the more accurately we will be able to project the extent of future sea level rise.”
