Previously undiscovered animals and plants may live in warm caves under Antarctica's glaciers, according to a new study led by the Australian National University.
Forensic analysis of soil samples from caves on Ross Island revealed traces of DNA from algae, mosses and small animals.
ANU Fenner School of Environment and Society senior lecturer Ceridwen Fraser, who led the study, said some of the DNA sequences were unrecognised in the researchers' database.
"That might just be because there are plants and animals in Antarctica that we haven't sequenced at those parts of the genome before, so they might just be your bog-standard plants and animals from Antarctica, or they might indicate something more exciting, like species that we don't know anything about yet," she said.
"There was one set of sequences that look like they're from some sort of arthropod, and arthropods are things like spiders, mites, a lot of insects ... You could imagine maybe a cave mite or some sort of insect-like organism that's down there."
Dr Fraser said she went in search of life in the caves because they were an unusually hospitable environment.
The caves systems were created from steam emitted by active volcano Mount Erebus, with some caves capturing significant light and recording temperatures of up to 25 degrees, she said.
"If you think of caves that get discovered elsewhere in the world, they're often swarming with life and sometimes species that we've never seen before that have adapted to those subterranean conditions," Dr Fraser said.
"It's completely conceivable that there might be species living under the ice in Antarctica that we know nothing about that have adapted to those cave geothermal environments that would be really cool."
But Dr Fraser likened the discovery of the DNA to the early investigation of a crime scene.
"It's sort of like ... saying we've detected that these people have come past here but we can't be sure that they did the crime," she said.
"There are strong winds in Antarctica, so it's possible that dead material has blown into the caves and we're picking that up in our analyses, or it might be really old from a time before those areas were under ice.
"That's why the next thing is it's important to find living plants and animals in there. To be honest I don't think people have really looked yet, so it's quite possible that there is life under the ice that we haven't seen."
Researchers will travel back to Antarctica within the next two years to try to find further signs of life.
The research, undertaken with Antarctica New Zealand and the Marsden Fund, has been published in international journal Polar Biology.