Scientists discover groundwater system in Antarctica

For the first time, scientists have mapped a huge, actively circulating groundwater system in deep sediments in West Antarctica. Such systems could have as yet unknown implications for how the frozen continent responds to, or perhaps even contributes to, climate change. Scientific article with results publishedA dynamic saline groundwater system mapped beneath an Antarctic ice stream / Science in the journal Science.

The researchers focused on the about 96 km wide Whillans Ice Stream, one of the fast-moving streams that feed the world's largest Ross Ice Shelf. Previous studies have identified a subglacial lake and a sedimentary basin extending beneath it. Shallow drilling revealed liquid water and a variety of microbes. But what lies beyond is still a mystery.

The research team used a magnetotelluric imaging technique that measures the penetration of natural electromagnetic energy into the ground, generated high in the atmosphere. Ice, sediment, water and rock conduct electromagnetic energy to varying degrees. By measuring the differences, you can create element maps, in a similar way that MRI works to map internal organs.

Scientists installed their instruments in snow pits for a day, after which they dug them up and moved them. They ended up getting data from 40 different locations.

The analysis showed that under the ice, the signal traveled to a depth of half a kilometer to almost two kilometers before hitting the bedrock. And these voids are completely filled with liquid water. The researchers estimate that if it is extracted, it will form a water column between 220 and 820 meters high - at least 10 times more than in the shallow hydrological systems at the base of the ice.

Salt water conducts energy better than fresh water. This made it possible to find out that groundwater becomes more saline with depth. This is logical, given that the deposits formed in the marine environment a long time ago. These waters probably last reached the surface during a warming period about 5,000–7,000 years ago.

It is noted that the underground system communicates with the outer ocean, releasing fresh water and making room for new melt under the ice. Active climate change could lead to an increase in currents, and carbon will enter the ocean, which is used by microbes under the ice. Scientists also do not deny that the process has already begun, and we are already swimming in Antarctic carbon.