(CNN) — Hidden deep in the ice sheet that covers Antarctica, scientists have discovered a vast body of water.
The groundwater system is found in deep sediments in West Antarctica and probably has the consistency of a wet sponge. The system will reveal an unknown part of the region and could have implications for how the frozen continent is responding to the climate crisis, according to new research.
“People have hypothesized that there could be deep groundwater in these sediments, but no one had done detailed imaging until now,” said lead author Chloe Gustafson, a postdoctoral researcher in oceanography at the University of California’s Scripps Institute. of California in San Diego, in a statement.
UC San Diego Scripps Institution of Oceanography researcher Chloe Gustafson prepares to set up a magnetotelluric station to map under the ice during 2018 fieldwork in Antarctica. (Credit: Kerry Key/Columbia University)
“Antarctica contains 57 meters of sea-level rise potential, so we want to make sure we include all the processes that control how ice flows from the continent to the oceans. Groundwater is currently a missing process.” he added in an email.
Research on water in Antarctica
The ice sheet covering Antarctica is not a rigid entity. Researchers in Antarctica have discovered hundreds of interconnected liquid lakes and rivers in recent years cradled in the same ice. But this is the first time large amounts of liquid water have been found in sediments beneath the ice.
The authors of this study, published Thursday in the journal Science, focused on the 60-mile-wide Whillans Ice Stream, one of six streams that feed the Ross Ice Shelf, the ice shelf. about the size of Canada’s Yukon Territory.
Gustafson and his colleagues spent six weeks in 2018 mapping the sediments beneath the ice. The research team used geophysical instruments placed directly on the surface to perform a technique called magnetotelluric imaging.
The team of researchers spent six weeks in Antarctica.
The technique can detect the different degrees of electromagnetic energy conducted through ice, sediment, freshwater rock and saltwater and create a map based on these different sources of information.
“We imaged from the ice bed to about three miles and even deeper,” study co-author Kerry Key, an associate professor of earth and environmental sciences at Columbia University, said in a separate statement.
The researchers calculated that if they could squeeze groundwater from the sediments in the 100 square kilometers they mapped at the surface, it would form a lake that was 220 to 820 meters deep.
“The Empire State Building to the antenna is about 420 meters high,” Gustafson, who conducted the research as a graduate student at Columbia University’s Lamont-Doherty Earth Observatory, said in the statement.
“In the shallow end, the water would rise halfway up the Empire State Building. In the deep end, it’s almost two Empire States stacked on top of each other. This is important because the subglacial lakes in this area are between 2 and 15 meters deep. That are about one to four floors from the Empire State Building.”
How did they get there?
The team checks data from a magnetotelluric station they used to map beneath the ice sheet.
The mapping showed that the water became saltier with depth, which was a result of the formation of the groundwater system.
Ocean water likely reached the area during a warm period from 5,000 to 7,000 years ago, saturated the sediment with salty seawater. As the ice progressed, fresh meltwater produced by pressure from above and friction at the base of the ice was forced into the upper sediments. It likely continues to seep and mix with groundwater today, Key said.
The researchers said more work is needed to understand the implications of the groundwater discovery, particularly with regard to the climate crisis and rising sea levels.
It was possible that the slow drainage of water from the ice into the sediment could prevent water from accumulating at the base of the ice, which would slow down the ice’s advance toward the sea.
However, if the surface ice sheet were to become too thin, the pressure drop would allow this deep water to flow out. This upward movement would lubricate the base of the ice and speed up its flow.
“This finding highlights groundwater hydrology as a potentially critical component in understanding the effect of water flow on the dynamics of the Antarctic ice sheet,” wrote Winnie Chu, an assistant professor at the Georgia Institute of Technology, in a commentary on the study published today. in the journal Science. She did not participate in the study.
