Tiny animals discovered in Antarctic lake deep beneath the ice

Scientists have made a surprising discovery in Antarctica: the carcasses of tiny animals were found in a lake that sits deep beneath one kilometer (0.6 miles) of Antarctic ice.

The scientists were drilling into Subglacial Lake Mercer to look for evidence of life, though finding tiny animals was “fully unexpected” according to David Harwood, a micro-palaeontologist at the University of Nebraska-Lincoln and a part of the expedition. The Subglacial Antarctic Lakes Scientific Access (SALSA) mission progressed from previous studies that looked at the lake through ice-penetrating radar and other remote-sensing techniques, by melting a portal through the ice and into the water of the lake below.

The animals the team discovered in the underground lake included crustaceans and a tardigrade, also known as a water bear. When they looked at samples from the lake through a microscope, they saw “some things that looked like squished spiders and crustacean-type things with legs … some other things that looked like they could be worms,” Harwood told Science News. Strangely, some of the creatures that they discovered were land-based animals, like the eight-legged tardigrade which tends to live in damp soil, and the creatures that looked like worms were actually tendrils from a plant or fungus that lived on land.

The team believe that the creatures lived in ponds and streams in the Transantarctic Mountains, which lie roughly 50 kilometers (31 miles) from Lake Mercer. This was during a brief warmer period when the glaciers of Antarctica receded to reveal the lake — which is calculated to have occurred either in the past 10,000 years or a massive 120,000 years ago. It is unknown how the creatures came to be in the lake in distant Antarctica, but it is known that as the warm period ended and colder temperatures returned to the region, huge sheets of ice formed over the lake and preserved and isolated it. It could be that rivers under the ice washed the creatures from the mountains down into the lake, or it could be that the creatures were frozen into a glacier and were dragged away from their mountain home.

This is the first time that life of this complexity has been found under the ice sheet, as previous research had found microbes in Lake Whillans, which is 31 miles from Lake Mercer, but never higher life.