Feb. 15 (UPI) -- Scientists have discovered a collection of strange sponge-like sea creatures living on a boulder under some 1,650 feet of Antarctic ice.
The unidentified lifeforms, detailed Monday in the journal Frontiers in Marine Science, were found by a team of geologists drilling through the Filchner-Ronne Ice Shelf, which stretches across part of the Weddell Sea.
"The boulder came from the land and probably dropped off the bottom of the ice shelf floating above," biogeographer Huw Griffiths of British Antarctic Survey told UPI in an email.
Griffiths, lead author of the paper describing the discovery, said the animals likely colonized the boulder after it fell onto the seafloor.
There is no light where scientists found the sea creatures. Directly above the boulder floats more than a quarter mile of ice. The animals are stationary, but if they could move, they would need to travel more than 160 miles to reach the open ocean.
The geologists who found the sponge-like organisms weren't looking for or expecting to find living creatures beneath the Filchner-Ronne Ice Shelf, where temperatures in the unfrozen seawater can reach 28 degrees Fahrenheit. They just wanted some sediment.
"They wanted the mud to be able to look at the history of the ice shelf," Griffiths said. "On this occasion, they hit a boulder instead of mud. This was not good news for the geologists, but it was an amazing find for biologists."
Video returned by the geologists was turned over to a team of marine biologists, including Griffiths, who specialize in studying harsh polar ecosystems.
"The team involved have made many such discoveries including many new species, but we usually do that work from a ship," Griffiths said. "This finding was a complete accident as we weren't even looking for this life when we found them."
Scientists aren't sure how these animals came to colonize the boulder or how exactly they survive in the frigid, lightless conditions beneath the ice shelf -- they said they don't even know what the organisms are.
"We have only had a quick glimpse on the video and that doesn't have enough detail to be able to identify them to species," Griffith said. "We think that there are at least two types of sponges and some other animals that we cannot identify. Given that we usually find new species when working in Antarctica, there is a good chance that they could be new to science."
It's possible the animals are uniquely adapted to life under an ice shelf. It's also possible the animals, still in their larval stage, were unwittingly swept under the ice shelf by ocean currents.
Many questions about the discovery remain. To answer them, researchers hope to find more boulders like the one featured in the newly published study.
"These findings show that polar ecosystems are even more diverse than we expected and that some animals can survive far further from daylight than we previously believed," Griffith said. "The next task is to understand how common these boulders and communities are and what role they play in the broader Antarctic ecosystem."