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March 21, 20253 min readStunning Antarctic Sea Creatures Discovered after Iceberg Breaks AwayA calving iceberg exposed a region that never before had been seen by human eyes, revealing a vibrant, thriving ecosystemBy Ashley Balzer Vigil edited by Andrea ThompsonA large sponge, a cluster of anemones, and other life is seen nearly 230 meters deep at an area of the seabed that was very recently covered by the George VI Ice Shelf in Antarctica. Sponges can grow very slowly, sometimes less than two centimeters a year, so the size of this specimen suggests this community has been active for decades, perhaps even hundreds of years. ROV SuBastian/Schmidt Ocean InstituteIn H. P. Lovecrafts chilling science-fiction novella At the Mountains of Madness, a group of researchers uncovers the ruins of an ancient alien civilization while exploring beneath Antarctica. Now a real team has investigated what lies beneath some of the frozen continents floating ice, and its findings are certainly otherworldly.Scientists onboard the Schmidt Ocean Institutes research vessel Falkor (too) sailed to Antarctica to study the nearby seafloor, the creatures that live there and the way climate change is affecting Antarctic ice and the ecosystems that evolved around it. But their plan was sidetracked after an iceberg the size of Chicago broke away from a nearby ice shelf in Bellingshausen Sea on January 13.The ice front left behind where the iceberg calved off in the Bellingshausen Sea.Alex Ingle/Schmidt Ocean InstituteOn supporting science journalismIf you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.That event presented an opportunity that was too good to pass up: the chance to explore the seafloor below the icebergs original locationlike overturning a rock or log in the woods to see what creatures lie hidden underneath. There was a sense of going into a complete unknown, says the expeditions co-chief scientist Sasha Montelli of University College London. We thought we might see some life there, but it was really surprising to see the degree to which life was thriving in such a hostile environment. And it wasnt just existing there but had apparently been sustained for a very long time.The researchers sent their underwater robot SuBastian into the deep and found an ecosystem filled with anemones that look like Dr. Seusss Truffula Trees, along with sea spiders, icefish, octopuses. Some of the creatures that are new species, and many may only be found near Antarctica. Beyond simply being remote, the continent has been isolated for millions of years by the Antarctic Circumpolar Current, which surrounds it like a moat around a castle.An octopus rests on the seafloor 1150 meters deep in the Bellingshausen Sea.ROV SuBastian/Schmidt Ocean InstituteThe tentacles of a solitary hydroid drift in currents 360 meters deep at an area of the seabed that was very recently covered by the George VI Ice Shelf. Solitary hydroids are related to corals, jellyfish, and anemones, but do not form colonies.ROV SuBastian/Schmidt Ocean InstituteBecause the Bellingshausen Sea is not much explored in terms of deep-sea biodiversity, we expect many new species from the expedition. And in fact, we have already confirmed some, including snails, polychaete worms, crustaceans and even fish, says the expeditions co-chief scientist Patricia Esquete of the Center for Environmental and Marine Studies and the University of Aveiro in Portugal.The researchers also encountered large vaselike sponges whose size hints at their age. Based on the size of the animals, the communities we observed have been there for decades, maybe even hundreds of years, Esquete said in a recent press release.The observations draw sharp contrast to previous studies of ecology below the ice, which either dropped cameras down through holes drilled in the ice or took place years after an iceberg calved. Those studies indicated that the ecosystems seemed to be quite impoverished, with a limited number of species, Esquete says. Now we know that under ice shelves, at least in the first 15 kilometers from the frontthe newly exposed area the new expeditions researchers were able to explore after the iceberg calvedthere are diverse, well-established ecosystems.A squid eats a fish at a depth of nearly 950 meters in the Bellingshausen Sea.ROV SuBastian/Schmidt Ocean InstitutePatricia Esquete inspects a suspected new species of isopod that was sampled from the bottom of the Bellingshausen Sea. It will take scientists years to describe all of the new species found during this expedition.Alex Ingle/Schmidt Ocean InstituteLess certain is how this vibrant ecosystem will fare now that the iceberg has broken away. Many deep-sea dwellers are adapted to unchanging conditions found in their environment, so they are highly sensitive to even small environmental shifts. For the life-forms uncovered in Bellingshausen Sea, the dramatic loss of their former iceberg ceiling may rock their ecosystem.Montelli says that the floating ice shelf that the iceberg broke away from has retreated inland by about 25 miles (40 km) over the past 50 yearsjust one example of accelerating ice loss on the continent. The ice loss from the Antarctic Ice Sheet is a major contributor to sea level rise worldwide, Montelli said in the recent press release. Our work is critical for providing longer-term context of these recent changes, improving our ability to make projections of future change.
