Hidden beneath the thick ice of West Antarctica lies a vast network of water—an interconnected system of subglacial lakes and rivers. This is the first time researchers have gathered direct empirical evidence about such hidden ecosystems, offering crucial clues about how Antarctic glaciers behave and how they melt.
A team from the Scripps Institution of Oceanography has become the first to map these concealed features beneath the ice and has published its findings in Science.
For decades, scientists have flown over the Antarctic ice sheet with radar and other tools to glimpse underground structures. The results have been imperfect. They showed sedimentary basins trapped between ice and bedrock, but they could not reliably determine water content or other key characteristics. The data existed, but it remained elusive to human analysis.
Below is a photograph captioned as penguins in Antarctica, from Pixabay.
However, the current research team has begun to solve that mystery. They traveled to the western sector of Antarctica, near the Whillan Current. This region is roughly 800 meters thick and spans about 100 kilometers in width, feeding the world’s largest ice shelf, the Ross Ice Shelf. Previous studies in this area had already suggested a subglacial lake and an underlying sedimentary basin. A few years ago, the outer ice layer was penetrated, revealing liquid water and a thriving microbial community. Yet what lay deeper still remained unknown.
The scientists employed the magnetotelluric method, which measures the natural electromagnetic energy that travels from the atmosphere into the Earth. By comparing how ice, seafloor sediments, fresh water, salt water, and bedrock emit different electromagnetic signals, researchers can generate digital maps similar to MRI scans.
The key to glacier dynamics
The team found groundwater in amounts large enough to influence ice flow. This finding suggests that future models must account for groundwater to accurately simulate glacier movement. Liquid water inside the ice can lubricate gravel layers and accelerate movement toward the sea.
Additionally, magnetotelluric signals provided insight into groundwater properties because fresh water appears differently from salt water in the images, according to lead author Chloe Gustafson.
Below is another photograph captioned Antarctica has a large body of groundwater, from Pixabay.
In the study’s second phase, seismic data supplied by co-author Paul Winberry of Central Washington University complemented the imaging. The analysis showed that under the ice, sediment thickness varied from about half a kilometer to nearly two kilometers before bedrock. A lake with depths ranging from 220 to 820 meters can exist within this subglacial system.
What effect these underwater lakes have on marine dynamics remains to be fully understood, but researchers are beginning to assess potential impacts. If warming oceans cause ice shelves to melt, seawater could permeate these sediments and raise the risk of rapid sea-level rise beyond current projections. Groundwater presence also affects carbon stored by microbial communities, potentially releasing significant amounts of gas that were previously underestimated.
A lake comparable in size to the island of La Gomera
In a separate study published in Geology, researchers examined East Antarctica under three kilometers of ice, discovering a 370-square-mile subglacial lake with an estimated 21 cubic kilometers of liquid water. By analyzing this lake and other subglacial hydrological features, scientists aim to reconstruct the ice sheet’s history.
Researchers from the University of Texas, among others, focus on how Antarctica looked before it froze, how climate change has shaped it over millions of years, and how current warming could alter its future. The lake may hold a record spanning the last 34 million years of ice cover.
Reference study: Science, doi: 10.1126/science.abm3301
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