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“Life finds a way,” declared actor Jeff Goldblum, who plays scientist Ian Malcolm in the 1993 film “Jurassic Park.”
Animal life was not what scientists expected to find in wolf-black seawater under nearly half a mile of floating Antarctic ice, but it seems to have found a way with the discovery of sea creatures that live in the extreme environment.
Geologists who took sediment cores from the seafloor below the giant Filchner-Ronne ice shelf on the southern edge of the Weddell Sea in Antarctica discovered what biologists believe are types of sponges. The finding was published Monday in Frontiers in Marine Science.
Geologists were more than 150 miles from the open ocean when they drilled a hole through the 3,000-foot-thick ice with a hot water drill and lowered a coring device and video camera into the dark seawater below. he.
They had expected the seabed to be muddy, but were dismayed when they hit a rock, which meant they couldn’t get the expected sediment samples. But to his surprise, the camera showed colonies of “stationary” animals attached to the rock, probably sponges and related sea creatures.
“It was a bit disappointing for them – they had spent weeks getting there and it didn’t work out,” 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 seen these [organisms] prior to.”
Antarctica is surrounded by more than half a million square miles of ice shelves, the Filchner-Ronne being one of the largest, covering more than 160,000 square miles, but the wells have revealed an area of seafloor below them of the size of a tennis court. “It’s a huge area, but we have a tiny widow in it,” Griffiths said.
Small mobile animals like shrimp and crustaceans called sea fleas had 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 and find food,” he said. “Whereas if you’re glued to a rock and you’re waiting for food to arrive, then the only thing that happens this year could happen to you.”
The teardrop-shaped bumps seen on the right of the video are clearly a type of sponge, while the stalked creatures on the left are similar to some other sponges found near Antarctica, he said. There are also indications that other animals may attach to the rock, such as tube worms, stalked barnacles or hydroids, which are related to jellyfish.
To survive, organisms would have to feed on floating material from other animals or plants, because it is impossible for plants to photosynthesize in sunless seawater. While the rock is about 150 miles from the ocean, the direction of the currents under the ice shelf suggests that the closest plant life is up to 1,000 miles away, Griffiths said.
But the question of how these animals obtain food will have to wait until another scientific expedition can visit the site, perhaps equipped with a remotely operated underwater vehicle that can retrieve samples from 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 studied life under polar ice for nearly 40 years but was not involved in the last study.
It appears that the animals attached to the rock moved there as microscopic larvae and then grew into their adult forms: “life is everywhere and the environment selects the species that will eventually thrive.”
A future stage will be to determine if the animals are similar to those in the open ocean or if they have evolved to live where they are now, Priscu said in an email. “[If] organisms evolved to live beneath ice shelves, they can provide us with a molecular clock that can be used to measure past climate changes in Antarctic ice. “
The discovery shows that life can exist in environments where science suggests it shouldn’t: “There are still things we have to learn,” Griffiths said. “There are still animals that can break the rules that we have written to them.”
