May 7, 2022 - Science

Scientists discover massive reservoir of water under Antarctic ice

Field site on the Whillans Ice Stream, West Antarctica. Credit: Kerry Key, Lamont-Doherty Earth Observatory, Columbia University
Field site on the Whillans Ice Stream, West Antarctica. Credit: Kerry Key, Lamont-Doherty Earth Observatory, Columbia University

Deep under the ice in West Antarctica, a massive reservoir of groundwater may help to drive ice from the interior of the continent to the ocean, scientists reported this week.

Why it matters: Determining how fast-flowing streams of ice work would allow researchers to better understand how ice melt in Antarctica contributes to sea level rise.

  • Right now, projections for sea level rise don't include the contributions from the groundwater reservoir to the timing, size and pace of ice streams.

Background: Scientists knew there is shallow water that moves through a network of channels, lakes and porous sediments just under the ice streams.

  • But for decades, they suspected there was also water deeper under the ice, much like aquifers on other continents.

What's new: Measurements of seismic activity and the electromagnetic fields around the Whillans Ice Stream in West Antarctica indicate there is a layer of sediment one-half-mile thick that holds water like a sponge, Chloe Gustafson, a geophysicist at the University of California, San Diego, and a team of researchers report in the journal Science today.

  • They estimate it contains 10 times more water than the shallower sources.
  • It is also saltier toward the sediment and becomes less salty toward the base of the ice.
  • That suggests the groundwater is being exchanged with fresh water in the subglacial lakes above it, possibly providing those lakes with carbon that supports the life observed there, Wired's Gregory Barber writes.

The big picture: "Ice streams transport about 90% of Antarctic ice from the interior out to edges," Gustafson says.

  • "I would bet there is groundwater beneath all the ice streams, and it is a continental-wide process that we haven’t truly accounted for."
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