“Life finds a way,” said actor Jeff Goldblum, scientist Ian Malcolm, in the 1993 film Jurassic Park.
Wildlife was not what scientists expected to find in the pitch-black seawater beneath nearly a mile of floating Antarctic ice, but it apparently found a way with the discovery of marine animals living in the extreme environment.
Geologists taking sediment cores from the seabed under the giant ice sheet Filchner-Ronne on the southern edge of Lake Weddell in Antarctica have discovered what biologists are sponge species. The finding was published Monday in Frontiers in Marine Science.
The geologists were more than 150 kilometers from the open ocean when they drilled a hole through the 3,000-foot-thick ice with a hot water drill and lowered a nuclear device and a video camera into the dark seawater below.
They expected the seabed to be mud, but were devastated when they hit a boulder, meaning they could not get the intended sediment samples. But to their surprise, the camera displays colonies of “stationary” animals attached to the rock – probably sponges and related marine animals.
“It was a bit of a disappointment for them – they spent weeks there and it did not work,” said marine biologist Huw Griffiths of the British Antarctic Survey, who is the lead author of the published study. “But for [biologists], it’s amazing because no one has ever seen it before [organisms] previously. ”
Antarctica is surrounded by more than half a million square miles of ice racks – the Filchner Ronne is one of the largest and covers more than 160,000 square miles – but boreholes have exposed a surface of the seabed beneath them only the size of a tennis court . “It’s a big area, but we have a little widow in it,” Griffiths said.
Small mobile animals such as shrimp and crustaceans called sea fleas have been seen under ice shelves before, but no one expected to see stationary animals like these. “The only things you would expect to find … are things that can wander around and get food,” he said. “While you are stuck on a rock and waiting for food to come to you, the one passing this year may pass by you.”
The blunt protrusions seen on the right side of the video are clearly a kind of sponge, while the back creatures on the left side are similar to some other sponges found near Antarctica, he said. There are also indications that other animals may be attached to the rock block, such as tube worms, stalked browns or hydroids, associated with jellyfish.
In order to survive, the organisms must feed on floating material from other animals or plants, as it is impossible for plants to photosynthesize in the sunless seawater. While the rock is located about 150 kilometers from the ocean, the direction of the currents under the ice shelf indicates that the nearest plant life is up to a thousand kilometers away, Griffiths said.
But the question of how these animals get food has to wait until another scientific expedition can visit the place, perhaps equipped with a remote-controlled underwater vehicle that can retrieve samples of the animals.
“All the ingredients for life exist under ice shelves,” said John Priscu, a professor of polar ecology at Montana State University, who has been studying life under polar ice for almost 40 years but who is not involved in the latest study. was not.
It seems that the animals attached to the boulder floated there like microscopic larvae, and then grew into their adult form: “life is everywhere and the environment chooses the species that eventually thrive.”
A future stage will be to determine whether the animals are similar to those in the open ocean, and whether they evolved to live where they are now, Priscu said in an email. ‘[If] if the organisms evolved under ice shelves, it could provide us with a molecular clock that could be used to measure climate-driven changes in the Antarctic ice. ”
The discovery shows that life can exist in environments where science suggests it should not: “There are still things we need to learn,” Griffiths said. “There are still animals that can break the rules we wrote for them.”