Directly below AntarcticaResearchers on the ice shelf have discovered dozens of creatures that thrive on small parts of the ocean floor. This is an unprecedented level of species diversity in an environment that has never been exposed to sunlight.
Research co-author David Burns, a marine biologist at the British Antarctic Survey, asked, “How rich life would you find if you asked me three questions at the beginning of the manuscript?” Not many. How rich will it be? ” It’s not. How will growth be? It’s very slow. And I would have been wrong in every way. “
Far below the Antarctic ice sheet, protected from the rays of the sun’s energy, life may exist, but it was considered rare. Most ecosystems are built on the foundations of photosynthetic organisms such as plants and algae, so such dark areas should not have enough food to support a wide variety of life.
Related: Time-lapse image of a retreating glacier
But when Gerhard Kuhn and Raphael Gromig of the Alfred Wegener Institute dug 656 feet (200 meters) of ice on the Ekström ice shelf with boiling water in 2018, they were able to scoop an additional 328 from the ocean floor. I was surprised. (100 m) below.
Ice shelves cover 600,00 square miles (1.6 million square kilometers) of the sea, and what’s under the ice may be very common. EarthThe least explored underwater habitat.
In such a dark and seemingly unruly environment, the team found fragments of life. When he realized he had discovered more than expected, Klaus Dieter Hillenbrand, a sedimentary scholar at the British Antarctic Survey, recommended sending submarine samples to Burns.
The debris pulled from under the ice shelf was clearly from another animal when examined under a microscope. After all, Burns identified 77 different species, far more than he should have reasonably found. This one sample was even more seed-rich than expected from the open shelf survey.
“Is this a prank?” Burns recalled what he thought when examining the specimen. “It’s like a sample of the entire research vessel, but from one drill hole.”
Many of the identified species were bryozoa, or fixed filter feeders that often looked like brains or moss. Melicerita obliqua And tube feeding worms, etc. Paralaeospira sicula, Above all. “This discovery of so many lives living in these extreme conditions is a complete surprise and reminds us of how unique and special Antarctic marine life is,” Burns said of Live Science. Told to.
Finding such an affluent life under an ice sheet that is always present is one thing, but explaining why it exists is a completely different matter. Marine organisms, especially filter feeders such as bryozoa, sponges, and jellyfish, should theoretically decrease as they move away from the open ocean. It was thought to be too delicate for the cruel temperatures of 28 degrees Fahrenheit (minus 2.2 degrees Celsius), eating algae that needed sunlight.
However, it was found that these animals feed on microorganisms such as ciliates and flagellates that are swept under the ice shelves by ocean currents. “Surprisingly, there’s enough,” Burns said.
Looking at the submarine communities of the polar continental shelves under ice-free water, they are not restricted by food.
Instead, they get much more than they could ever consume. Besides, they don’t consume much. These are animals that stick to the floor and do not form large bodies of energy-hungry tissues. As such, they can survive the torrents of food that come their way.
“It’s life in a super slow lane,” Burns said.
In addition, radiocarbon dating reveals that these bottom occupants are not new tenants under the shelves of Antarctica.
“Even though we live 3-9 km from the nearest open ocean, there may have been an oasis of life under the ice shelves for nearly 6000 years,” said Kuhn, the leader of the drilling project. There is. ” In the statement.. The oldest wreckage was 5,800 years old, but only 20 of the hundreds of fragments are dated. Future data may push this estimate further into the past. No matter how long it has existed, it is clear that there has been an almost isolated life here for thousands of years.
“This may be the most undisturbed habitat on the planet,” Burns said of the space between the ocean floor and the ice above it.
He said that lack of obstruction may explain the species diversity of the ecosystem. Under ice, there are no storms, floods, or fires, enabling all species that can survive the time and stability needed to radiate to all available niches.
But pristine habitats like these may be part of the first habitat to succumb to man-made things. Climate change, Burns said. As the Antarctic ice shelves recede, these unique environments can be lost.
And once lost, the environment cannot be recreated. “People talk about recreating and rewilding, and trying to protect and preserve, but we don’t do that here,” Burns said.
This study was published in the journal on December 20th. Current biology..
Originally published on Live Science.
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