Scientists have discovered a hidden ecosystem beneath a colossal iceberg the size of Chicago, which they speculate may have been dwelling there for hundreds of years.
This hidden habitat is overflowing with never-seen-before life forms, including anemones, sponges, hydroids, and corals, supporting a wide array of animal life such as icefish, giant sea spiders, and octopus. The ecosystem, nestled beneath an iceberg named A-84 in the Bellingshausen Sea off Antarctica, was found when the iceberg broke away from the George VI Ice Shelf.
Researchers used a remotely operated vehicle (ROV), SuBastian, to explore the deep seafloor, and they were astonished to find a significant amount of biomass and biodiversity at a depth of 230 meters. The team suspects that several new species might have been discovered.
“We seized upon the moment, changed our expedition plan, and went for it so we could look at what was happening in the depths below. We didn’t expect to find such a beautiful, thriving ecosystem,” said expedition co-chief scientist Dr. Patricia Esquete of the Centre for Environmental and Marine Studies (CESAM) and the Department of Biology (DBio) at the University of Aveiro, Portugal.
“Based on the size of the animals, the communities we observed have been there for decades, maybe even hundreds of years.”
In 2021, British Antarctic Survey researchers first indicated the bottom-dwelling life beneath the Filchner-Ronne ice shelf. However, very little is known about what lives on the Antarctic seabed below thick chunks of floating ice.
Scientists are still uncertain about the precise mechanisms that fuel this ecosystem. Deep-sea ecosystems typically rely on surface nutrients that rain from above, but, with the cover of 150-meter-thick ice, this ecosystem has been cut off from such inputs for centuries. Researchers hypothesize that lifeforms here survive purely on nutrients flushed by ocean currents.
SuBastian explored this newly found biome for over eight days and collected biological samples, such as coral and sea sponges. Since Sponges grow only a few centimeters a year, this likely indicates that the ecosystem here has existed for centuries.
“The science team was originally in this remote region to study the seafloor and ecosystem at the interface between ice and sea,” said Schmidt Ocean Institute Executive Director Dr. Jyotika Virmani.
“Being right there when this iceberg calved from the ice shelf presented a rare scientific opportunity. Serendipitous moments are part of the excitement of research at sea – they offer the chance to be the first to witness the untouched beauty of our world.”