These lakes, buried under kilometres of ice, fill and drain in long cycles, altering ice sheet dynamics and potentially influencing global sea level rise. Researchers observed 12 complete filling and draining events, raising the worldwide total of documented cycles to 48. Five interconnected networks of subglacial lakes were also revealed.
"Only 36 complete cycles had been recorded globally before this study. Observing 12 more demonstrates how dynamic Antarctica's subglacial hydrology really is," said lead author Sally Wilson, a doctoral researcher at the University of Leeds.
The team relied on CryoSat's radar altimeter, which measures ice sheet height variations with high precision. As subglacial lakes refill and drain, the surface rises and falls, leaving a detectable signal across time. This dataset, spanning 2010 to 2020, enabled scientists to map changes with unprecedented clarity.
"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," added co-author Anna Hogg, professor at the University of Leeds.
Such findings are critical because current climate and ice sheet models rarely incorporate subglacial hydrology. "By mapping where and when these lakes are active, we can start to quantify their impact on ice dynamics and improve projections of future sea level rise," Wilson said.
CryoSat, launched in 2010 under ESA's FutureEO programme, monitors polar ice sheet thickness, sea ice distribution, and glacier dynamics. ESA Polar Science Cluster coordinator Martin Wearing noted, "The more we understand about the processes affecting the Antarctic Ice Sheet, the more accurately we can project the extent of future sea level rise."
Subglacial lakes form when geothermal and frictional heat melt ice at its base. The water collects in depressions and occasionally drains, reducing friction and allowing ice to slide more rapidly toward the ocean. While many lakes remain stable, some, such as those identified in this study, undergo periodic cycles that affect ice sheet flow.
One of the largest known subglacial reservoirs is Lake Vostok, beneath four kilometres of East Antarctic ice. It contains enough water to overflow the Grand Canyon by at least a quarter, though it is believed to be stable. If such a giant lake were ever to drain, the consequences could ripple through ocean circulation, ecosystems, and global sea levels.
Research Report:Detection of 85 new active subglacial lakes in Antarctica from a decade of CryoSat-2 data
Related Links
CryoSat
Beyond the Ice Age
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