An international team of scientists confirmed for the first time the existence of groundwater under an Antarctic ice stream, something that was suspected but that until now had not been verified. The researchers of the columbia university have mapped a huge groundwater system actively circulating in sediments deep in the West Antarctica. The research, published this Thursday in the science magazinehas been led by scientists from the Scripps Institution of Oceanography.
The study provides insights into the sediments beneath the Antarctic ice, an inaccessible part that has so far gone unexplored and that will help scientists better understand how the frozen continent works and how it changes in response to climate.
“Ice streams are important because they funnel about 90 percent of Antarctica’s ice from the interior to the margins,” said Chloe Gustafson, a postdoctoral researcher at the Scripps Institution of Oceanography. University of California in San Diego. And the groundwater under these ice currents “can affect their flow and, therefore, influence the transport of ice out of the Antarctic continent,” the researcher clarified.
The key to the discovery, electromagnetism
To do the study, the researchers used a electromagnetic geophysical method (EM) that uses the variations of the electric and magnetic fields of the earth to measure the resistivity of the ground, a technique that consists of scanning in the direction of the ground to see how it behaves when waves pass.
Gustafson and his colleagues collected Whillans ice stream datawhich has some 800 meters thick and a hundred kilometers wide and feed the ross ice shelf, the largest in the world. Those data complemented earlier information from deeper and shallower areas.
Following the research-proven success of this technique, Gustafson believes it’s time “people start looking at electromagnetism as part of the standard Antarctic geophysical toolkit. magnetotelluric signalspassively collected and naturally generated to measure variations in electrical resistivity, gave researchers insights into the characteristics of groundwater, “since freshwater shows up very differently in our images than freshwater.” salty,” said Gustafson.
Enough water to form a lake up to 820 meters deep
In a second part of the investigation, the EM measurements were complemented with data from seismic images collected by Paul Winberry of the Central Washington University, co-author of the study. This analysis showed that, depending on location, a thick layer of sediment it extends below the ice base from half a kilometer to almost two kilometers before reaching bedrock.
They also confirmed that sediments are loaded with liquid water to the bottom. According to his calculations, if all were removed, it would form a lake between 220 and 820 meters deep.
A discovery that fuels the possibility of finding water on other planets
The team only imaged one ice stream, but “there is probably groundwater beneath more Antarctic ice streams,” they say. Furthermore, the authors believe that it is groundwater under similar conditions may exist on other planets or moons that release heat from their interior and that are covered with ice.
The existence of subglacial groundwater also has implications for the carbon stored by communities of microbes adapted to seawater and could release “significant amounts” of this gas that until now had not been considered.
“This study is just a start to address all of these questions. It is confirmation that deep groundwater has dynamics that have transformed our understanding of the behavior of ice streams, and will force subglacial water models to change.”