Stationary sponge-like animals and potentially previously unknown species have been discovered clinging to a rock far below an ice shelf of the Antarctica.
During an exploratory study, investigators drilled 900 meters of ice on the Filchner-Ronne ice shelf, located in the southeast of the Weddell Sea. At a distance of 260 km from the open sea, in complete darkness and with temperatures of -2.2 ° C, very few animals have been observed under these conditions.
In a statement the biogeographer and lead author, Dr Huw Griffiths of the British Antarctic Survey, stated in a statement:
“Our discovery raises many more questions than it answers, for example, how did they get there? What are they eating? How long have they been there? How common are these covered boulders in life? Are these the same? species that we see out on the ice shelf or are they new species? And what would happen to these communities if the ice shelf collapsed? “
The floating ice shelves represent the largest unexplored habitat in the Southern Ocean. They cover more than 1.5 million square kilometers of the Antarctic continental shelf, but only a total area similar in size to a tennis court has been studied through eight previous boreholes.
Current theories about what life could survive under ice shelves suggest that all life becomes less abundant as it moves away from the open ocean and sunlight.
Previous studies have found some small mobile predators and scavengers, such as fish, worms, jellyfish or krill, in these habitats. But filter-feeding organisms, which depend on food supplies from above, were expected to be among the first to disappear further under the ice.
So it came as a surprise when the team of geologists, drilling through the ice to collect sediment samples, hit a rock instead of mud on the ocean floor. They were even more surprised by the video footage, which showed a large rock covered in strange creatures.
This is the first record of a hard-substrate community (i.e. a rock) deep within an ice shelf and it seems to go against all previous theories about what kinds of life could survive there.
Given the water currents in the region, the researchers estimate that this community may be up to 1,500 kilometers from the closest source of photosynthesis.
Other organisms are also known to collect nutrients from glacier melt or chemicals from methane seeps, but researchers won’t know more about these organisms until they have the tools to collect samples of these organisms – a significant challenge in and of itself.
“To answer our questions, we will have to find a way to get close to these animals and their environment, and that is under 900 meters of ice, 260 kilometers from the ships where our laboratories are located.”Griffiths continues.
“This means that, as polar scientists, we will have to find new and innovative ways to study them and answer all the new questions that we have.”
Griffiths and the team also note that with the climate crisis and the collapse of these ice shelves, time is running out to study and protect these ecosystems.