Discovery in Antarctica: a huge water reservoir hidden under a glacier

Found in Antarctica
Huge water tank hiding under glaciers

06/05/2022 11:44 AM

Scientists have long speculated that huge aquifers could be hidden beneath Antarctica’s ice. Now the expedition team finds such an aquifer.

Researchers have identified a huge underground water reservoir near the Ross Ice Shelf in Antarctica. Liquid water is found in a sedimentary basin up to 1.3 km deep. If the sediment is removed, the height of the water column will be between 220 and 820 meters. The discovery team hypothesizes that water affects the flow velocity of the Whillans Glacier and that there are other deep water reservoirs in Antarctica. The study conducted by the research group led by Chloe Gustafson of Columbia University in Palisades (New York, USA) is located in Published “Science” magazine.

“Others have hypothesized that there may be deep groundwater in these sediments, but no one has done detailed imaging yet,” Gustafson explained. She and her team used seismometers and the so-called passive seismic method to draw conclusions about underground structure from analysis of light seismic waves. They also used a technique previously used only in Antarctica to reveal structures ten kilometers or more deep: magnetology.

Scientists are evaluating data on the electrical conductivity of structures underground. Natural magnetic fields release eddy electric currents into the Earth’s interior, which in turn generate magnetic fields that can then be recorded and analyzed. Using this technique, Gustafson and colleagues were able to determine the depth and extent of the sedimentary basin. Since salt water conducts electricity better than fresh water, they were also able to determine the salinity of the water: it is lower at the top of sediment than in seawater, but increases with depth.

A note on the huge sea basin

Researchers explain this result as follows: thousands of years ago, the sedimentary basin was a sea floor, which is why the sediments were filled with salt water. For the researchers, a low salt content is an indication that the water reservoir is connected to meltwater on the glacier’s bottom, meaning that meltwater has seeped inland. The water on the bottom of the glacier reduces friction as the glacier moves over rocks or sediments. So the water affects the glacier’s flow rate and the amount of ice that ends up in the sea – which then contributes to sea level rise as a result of climate change.

In order to better understand the impact of groundwater on glacier behavior, these water reservoirs should be incorporated into the next generation of ice sheet models, the scientists recommend. They also advocate the use of ferromagnetism, a method of measurement based on electromagnetism: “I hope that people will look at electromagnetism as part of the standard Antarctic geophysical toolkit,” said Gustafson, who is also a professor at UCSD in Jolla (LA). California, USA).

in one “Science” comment refers to Winnie Choo from Georgia Institute of Technology in Atlanta (Georgia, USA) He suggests that groundwater may also contribute to the glacier’s slow flow: “If the aquifer could hold a large amount of subglacial water, the amount of lubricating water that contributes to the slip on hard ground would decrease.” How groundwater actually affects glacier behavior remains to be researched.