Scientists have discovered some strange and unexpected creatures living far beneath the Antarctic ice shelf, according to a new study published by Frontiers.
This is the first time a hard substrate community has been found deep beneath an ice shelf, and the discovery contradicts previous theories of what types of life could survive there.
During an expedition to the Filchner-Ronne Ice Shelf, which is located in the southeastern Weddell Sea, researchers drilled through 900 meters of ice. At a distance of 260 kilometers from the ice front, the site was under complete darkness with temperatures of -2.2 degree Celsius.
While very few animals have ever been observed in such conditions, scientists found that a large boulder on the seafloor was covered with sponge-like stationary animals.
“This discovery is one of those fortunate accidents that pushes ideas in a different direction and shows us that Antarctic marine life is incredibly special and amazingly adapted to a frozen world,” said study lead author Dr. Huw Griffiths of the British Antarctic Survey.
“Our discovery raises so many more questions than it answers, such as how did they get there? What are they eating? How long have they been there? How common are these boulders covered in life? Are these the same species as we see outside the ice shelf or are they new species? And what would happen to these communities if the ice shelf collapsed?”
Floating ice shelves cover more that 1.5 million square kilometers of the Antarctic continental ice shelf, yet only a total area similar in size to a tennis court has been explored.
“Prior to this study, our knowledge of these habitats and the life they support was restricted to what has been observed from eight boreholes drilled for geological and glaciological studies,” wrote the researchers.
It has been widely assumed that whatever life forms could survive beneath ice shelves become less abundant as you move farther away from open water and sunlight. In the past, some small mobile scavengers and predators like fish and worms have been spotted in these habitats.
The researchers said that the local currents suggest this community is somewhere between 625 and 1500 kilometers in the direction of water flow from the nearest region of photosynthesis.
There are some organisms that depend on nutrients from glacial melts or chemicals from methane seeps to survive in such extremities, but little is known about the new creatures until the researchers have an opportunity to study them further.
“To answer our questions we will have to find a way of getting up close with these animals and their environment – and that’s under 900 meters of ice, 260km away from the ships where our labs are,” said Dr. Griffiths. “This means that as polar scientists, we are going to have to find new and innovative ways to study them and answer all the new questions we have.”
The experts noted that with the climate crisis and the collapse of these ice shelves, time is running out to study and protect these ecosystems.
“This new evidence requires us to rethink our ideas with regard to the diversity of community types found under ice shelves, the key factors which control their distribution and their vulnerability to environmental change and ice shelf collapse.”
The study is published in the journal Frontiers in Marine Science.
By Chrissy Sexton, Earth.com Staff Writer