Scientists used 10 years of satellite data to identify 85 previously unknown lakes hidden beneath Antarctic ice.
The new lake is “active,” draining and refilling regularly, changing size and shape over months and years, researchers said. The ice age activity affects the stability of the glaciers and its crushing movement on the Antarctic bedrock, which could affect the global sea level, the team noted.
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Before this latest discovery, 146 active glacial lakes were already known in Antarctica. The new study brings a total of 231 active lakes to add to scientists’ understanding of subglacial lake drainage and replenishment, study author Sally Wilson said in a statement.
“They’re a great doctoral student at the Institute of Climate and Atmospheric Science at Leeds University,” said Wilson, a doctoral student at the Institute of Climate and Atmospheric Sciences, “They’re very happy to be aware of.” “Only 36 complete cycles were observed worldwide prior to the study, from the start of subglacial filling to the end of drainage. We observed 12 more complete filling and drainage events, bringing the total to 48.”
Subglacial lakes are pools of molten water that form when geothermal heat rises from inside the Earth to the bottom of the ice sheet, or when sufficient frictional heat is generated by ice crushing the bedrock. Subglacial lakes sometimes drain regularly, lubricate the bottom of the ice sheet, helping to slide down the bedrock, and accelerate ice movement towards the ocean.
For this study, researchers analyzed data captured between 2010 and 2020 from the ESA Cryosat-2 satellite, measuring variations in sea ice, glaciers and ice sheet thicknesses around the world. The cryosat-2 is equipped with an instrument called a radar altimeter that can detect small changes in the height of ice features, including changes that occur from lakes discharged and filled at the base of the ice.
The data revealed dozens of locations where the Antarctic ice sheets have sub-glacial lakes discharged and replenished under the surface, resulting in dozens of locations where the Antarctic ice sheets have sub-sloped and slightly risen. The observations also showed 25 lakes with interconnected drainage and reversion cycles, as well as five glacial lake networks that they had never seen before, the researchers published September 19th in Nature Communications.
The results are important. This is because it could help scientists improve their understanding of ice sheet dynamics and how they affect the global sea level, and help researchers design more accurate climate and earth models. “The numerical model we currently use to project the contribution to sea level rise across the ice sheet does not include subglacial hydrology,” Wilson said. “We will use these new datasets of subglacial lake locations, extents and times of change to cultivate an understanding of the processes driving water flow below the Antarctic.”
It is stable in subglacial lakes in Antarctica, so it does not drain and refill. An example is Lake Vostok, located beneath the ice sheet in the East Antarctica, and holding enough water to fill the Grand Canyon, according to a statement. If Lake Vostok begins to empty, it could affect the entire ice sheet and raise the global sea level, researchers noted.
“The more you understand the complex processes affecting Antarctic ice sheets, such as meltwater flow at ice sheet bases, the more accurate we can project the range of future sea level rise,” concluded Martin, digital twin earth scientist and ESA polar science cluster coordinator, in a statement.
Antarctica Quiz: Test your knowledge of the frozen continents of the Earth
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