Researchers have made the first detection of groundwater beneath an Antarctic ice stream. The discovery confirms what scientists had already suspected but had been unable to verify until now.
Scientists require data from all parts of the Antarctic ice sheet to understand how the system works and how it changes over time in response to climate. The research provides a glimpse of a previously inaccessible and unexplored part of the Antarctic ice sheet and improves scientists’ understanding of how it might affect sea level.
“Ice streams are important because they funnel about 90% of Antarctica’s ice from the interior out to the margins,” said Chloe Gustafson, a postdoctoral researcher at UC San Diego’s Scripps Institution of Oceanography. Groundwater at the base of these ice streams can affect how they flow, thus potentially influencing how ice is transported off of the Antarctic continent.
Although the team imaged only one ice stream, there are many more in Antarctica. “It suggests that there is probably groundwater beneath more Antarctic ice streams,” Gustafson said.
A team of scientists from Scripps Oceanography and Columbia University’s Lamont-Doherty Earth Observatory led the project. Gustafson and six co-authors reported their findings in the May 6, 2022, issue of the journal Science.
“It’s been a hypothesis from our understanding of how the planet works that there’s groundwater under Antarctica, but we haven’t been able to measure it before,” said study co-author Helen Amanda Fricker, a Scripps glaciologist and co-director of the Scripps Polar Center.
The researchers measured the groundwater during the 2018-2019 field season by using a ground-based geophysical electromagnetic (EM) method called magnetotellurics. The method uses variations in Earth’s electric and magnetic fields to measure subsurface resistivity. This study was the first time the method had been used to search for groundwater beneath a glacial ice stream.
Groundwater may exist under similar conditions on other planets or moons that are releasing heat from their interiors, Key said.
“You can imagine a frozen lid over a liquid interior, whether it’s completely liquid or liquid-saturated sediments,” he said. “You can think of what we see in Antarctica as potentially analogous to what you might find on Europa or some other ice-covered planets or moons.”
The existence of subglacial groundwater also has implications for the release of significant quantities of carbon that were previously stored by seawater-adapted communities of microbes.