Antarctica Groundwater Detected by Scientists Below the Whillans Ice Stream

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Antarctica
Courtesy of Tak (Flickr CC0)

Researchers have hypothesized that the groundwater below the West Antarctic ice sheet has been an unknown region. The water volume is comparable to several hundred meters deep waterholes. The water detected by scientists below the Whillans Ice Stream is presumably duplicated beyond the White Continent.

This discovery is the first time scientists have detected groundwater underneath an ice creek in Antarctica, which could redefine our knowledge of how this freezing continent responds to global warming and the type of mysterious organisms that lurk underneath it.
The recently discovered groundwater system is like a giant sponge of 0.5 to 1 kilometer [0.3 to 1.2 miles], made of permeable residue and drenched with water. In a statement, Chloe D. Gustafson, lead author of the study, said:

These sediments I like to think of as a giant sponge. If you could squeeze out all that water and pool it on the surface, the water would range anywhere from about 220m in depth all the way up to 820m. For comparison, the Empire State Building is about 440m tall. So at the shallowest, this water would go halfway up the Empire State Building, and at the deepest it would almost submerge two Empire State Buildings.

The ice cap covering Antarctica is not completely solid. It is interconnected with hundreds of liquid rivers and lakes nestled in the ice.
The authors of this study, published in the journal Science, focused on the Whillans Ice Stream, roughly the size of Canada’s Yukon Territory, about 60-mile-wide (96.6-kilometer-wide), one of six streams grazing the Ross Ice Shelf.

Antarctica
Mt Wallace, Yukon Territory Courtesy of WherezJeff (Flickr CC0)

Gustafson and her associates used geophysical instruments to map the ice using a magnetotelluric imaging technique to measure the different electromagnetic energy conducted by ice, bedrock, sediment, freshwater, and saltwater to form a map from these diverse sources. The team concealed these devices in shallow craters and collected data from approximately four dozen other spots on the ice stream.

How did it get there?

The data from the magnetotelluric station revealed that the water gets saltier with depth, resulting from how the groundwater system formed.

Ocean water presumably reached the location and doused the sediment with seawater during a warm period some 7,000 years ago. Fresh meltwater produced by pressure from above and friction at the ice base was forced into the upper deposits when the ice advanced. It probably continues to filter down and mix into the groundwater.

The researchers said more work needed to be done to understand the implications of groundwater discovery. Scientists must learn more about the linkage between groundwater and ice sheet hydrology before saying anything definitive about how groundwater hydrology may modify weather change that impacts Antarctica.

It was possible that the slow draining of water from the ice into the sediment could prevent moisture from building up at the base of the ice.
However, if the surface ice cap were light, the force reduction could let this deep water up and lubricate the ice base to rev its flow.

Written by Janet Grace Ortigas
Edited Sheena Roberson

Sources:
CNN: Massive amount of water found below Antarctica’s ice sheet for 1st time; by Katie Hunt
BBC: Huge volume of water detected under Antarctic ice; by Jonathan Amos
Live Science: ‘Giant MRI of Antarctica’ reveals ‘fossil seawater’ under ice sheet; by Nicoletta Lanese

Featured and Top Image Courtesy of Tak’s Flickr Page – Creative Commons License
Inset Image Courtesy of WherezJeff’s Flickr Page – Creative Commons License

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