The discovery may have implications for how the frozen continent responds to or may even contribute to climate change.

We know that even Antarctica, the coldest area on Earth, cannot escape the effects of climate change. To properly understand how the warming climate is affecting the South Pole, it is very important that researchers have data from all parts of the Antarctic ice sheet and that they understand how the complex system works. A new study makes an important contribution. Because for the first time, scientists have discovered groundwater under an Antarctic ice flow; something that has been suspected for a long time, but could not be confirmed before.

ice flow

Ice flows are nothing more than fast-flowing ice rivers, which according to study leader Chloe Gustafson are very important. “They transport about 90 percent of the Antarctic ice from the interior to the edges,” she explains. To understand what goes on under such an ice stream and whether groundwater could possibly be found, the researchers took a closer look at the so-called Whillans Ice Stream; an ice stream about 800 meters thick.

Research sites on the Whillans Ice Stream. Electromagnetic display stations were set up in place of the yellow markings. Image: Chloe Gustafson

New method

The researchers searched for groundwater using an electromagnetic technique called magnetotellurica. This method uses variations in the Earth’s electric and magnetic fields to measure underground resistance. Ice, sediments, fresh water, salt water and rock all conduct electromagnetic energy to varying degrees. And by measuring those differences, researchers can put together MRI-like maps. Although this technique is not often used in polar environments, the researchers show its potential. Because with the help of this new method, they discovered an enormous amount of groundwater in Antarctica for the first time.

For decades, scientists have studied the Antarctic ice sheet using radars and other instruments to visualize underground features. These missions have uncovered sedimentary basins sandwiched between ice and bedrock, among other things. The downside, however, is that aerial observations generally only reveal the rough outlines of such features; not the water content or other properties. So the researchers decided to take a different tack in the new study.

The discovery of groundwater is an important step. For although its existence in Antarctica has long been suspected, it could not be established with certainty. “It was a hypothesis based on our understanding of how the planet works, but we haven’t been able to measure it before,” explains Fricker. In the current study, the team mapped only one ice flow. But there are many more fast-flowing rivers in Antarctica. “This suggests that groundwater likely exists under multiple Antarctic ice flows,” Gustafson said.

Empire State Building

The team calculated that if they squeezed the groundwater from the sediments to the surface, it would form a lake 220 to 820 meters deep. “The Empire State Building is about 420 meters high,” Gustafson says. “This means that the water would reach halfway up the Empire State Building or even enclose two Empire State Buildings stacked on top of each other. This is important because the subglacial lakes in the area are two to fifteen meters deep. That’s about one to four floors of the Empire State Building.”

Climate change

The study provides a glimpse into a previously inaccessible and unexplored area of ​​the Antarctic ice sheet and improves our understanding of how sea levels may be affected in unknown ways. Groundwater at the base of ice flows can influence how they flow. And that in turn affects how ice is transported on the Antarctic continent. In addition, the discovery could have implications for how the frozen continent responds to, or possibly even contributes to, climate change. For example, the existence of subglacial groundwater has implications for the release of significant amounts of carbon previously stored by seawater-adapted microbes. “There may be more carbon being transported to the ocean than we thought,” Gustafson said. In addition, if deep groundwater is pushed upward by the warming climate and thinning ice, it could carry geothermal heat generated naturally in the bedrock; this allows ice to thaw further and be propelled forward, moving the ice out to sea even faster. And that while the Whillans Ice Stream already transports one meter of ice to the sea per day.

Although there are still many questions about the exact consequences of the discovery of groundwater in Antarctica and its link with climate change, the study does show the important added value of applying electromagnetic techniques in polar environments. “I hope people start to see electromagnetism as part of the standard geophysical toolkit for Antarctica,” Gustafson said. In addition, the discovery of groundwater in Antarctica may also have implications for our understanding of other celestial bodies. Groundwater could in fact exist under similar conditions on other planets and moons that give off heat from their interiors. And that means that what researchers have now discovered in Antarctica may be analogous to what we can find on Jupiter’s moon Europa or other ice-covered planets or moons.