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Antarctica is hiding a huge amount of water beneath its surface. Researchers have long suspected that there might be groundwater buried beneath the ice, but until now there has been no conclusive evidence to confirm that suspicion.

Within Antarctica’s ice sheet, corridors of relatively fast-moving ice flow to the ocean. “Ice streams are responsible for bringing 90 per cent of Antarctica’s ice out into its margins, so they’re really important for understanding how ice in Antarctica ultimately goes into the ocean,” says at the University of California, San Diego.

“They’re sort of like water slides, in that if there’s water at the base of your ice stream, it can go very quickly, but if there’s no water there, you can’t go very fast,” she says.

Researchers already knew that shallow pools of water –­­­ typically millimetres to a few metres deep –­­­ can sit between the ice streams and the ground below. But Gustafson and her colleagues wanted to know whether there was a larger reservoir of moving water beneath the Whillans ice stream in West Antarctica.

By measuring seismic activity and electromagnetic fields, they found a kilometre-thick layer of sediments saturated with a mix of fresh glacier water and ancient seawater.

It contains more than 10 times as much water as the shallower pools beneath the ice stream, and water seems to flow between the deep and shallow areas.

The apparent connection suggests the groundwater may be important for controlling the flow rate of the ice streams, a process that is crucial to understand for predicting the effects of climate change on sea level.

“Antarctica as a whole, the whole ice sheet, contains [enough water to lead to] about 57 metres’ worth of sea level rise,” says Gustafson. “Ultimately, we want to understand how quickly that ice is going to flow off the continent into the ocean and affect that sea level rise.”

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