Long jellyfish against black backdrop
A giant phantom jellyfish floats in the Bellingshausen Sea off Antarctica. ROV SuBastian / Schmidt Ocean Institute
Earlier this year, an iceberg the size of Chicago broke off the Antarctic Peninsula. When the gigantic iceberg calved, it revealed a previously hidden 209-square-mile area of seafloor that had never been accessible to humans before.
By coincidence, an international team of scientists was working nearby on a research vessel floating in the Bellingshausen Sea. They dropped what they were doing and immediately pivoted their research plans so they could investigate the mysterious seabed using a remotely operated vehicle.
They didn’t expect to find much—after all, what creatures could survive in the cold, dark depths beneath such a thick crust of ice?
But, somehow, life finds a way: The seafloor was crawling with critters of all shapes and sizes, from centuries-old sponges and cup corals to octopuses, snails, worms, sea spiders, icefish and even a rare giant phantom jellyfish. Though they’re still analyzing their findings, the team expects they’ll be able to identify several new species from the serendipitous expedition.
Reddish octopus
An octopus rests on the seafloor some 3,770 feet deep in the Bellingshausen Sea off Antarctica. ROV SuBastian / Schmidt Ocean Institute
“We were really surprised and amazed by the diverse ecosystems and the rich ecosystems we found down there,” says Patricia Esquete, an ecologist at Portugal’s University of Aveiro and the expedition’s chief scientist, to the Washington Post’s Dino Grandoni.
The iceberg, named A-84, broke off from the southern end of the George VI Ice Shelf on January 13. Measuring 19 miles long by 11 miles wide, A-84 was quickly carried away by coastal ocean currents and began “ricocheting” off parts of the Antarctic coastline, according to NASA’s Earth Observatory. Scientists have since been tracking the “potato-shaped” iceberg’s movements using satellite imagery.
Iceberg breaking off and moving around
Scientists tracked A-84's movements using satelite imagery. NASA Earth Observatory
The day A-84 calved, scientists were nearby onboard the Falkor (too), a research vessel owned by the nonprofit Schmidt Ocean Institute. They were focused on studying how other ice-shelf systems had changed over time.
But they decided to alter their plans and divert the research vessel to take advantage of the rare opportunity, “because you cannot predict this calving and subsequent drifting with accuracy,” says Aleksandr Montelli, a geophysicist and glaciologist at University College London and the expedition’s co-leader, in a statement.
“Ice shelves are among the most hostile and most remote environments on the planet, and they’re extremely difficult to get underneath,” he adds.
Research vessel near iceberg
The research vessel Falkor (too) was in the right place at the right time. Alex Ingle / Schmidt Ocean Institute
The group—which consisted of researchers from Portugal, the United Kingdom, Chile, Germany, Norway, New Zealand and the United States—was able to reach the newly exposed area less than two weeks later, on January 25.
Using a remotely operated underwater vehicle called SuBastia n, they spent eight days capturing photos and videos of the seafloor at depths of up to 4,265 feet. They also collected biological and geological samples, including a long gravity core full of sediment layers from the previously obscured seafloor.
Researchers looking at a sediment core
Scientists took a long gravity core to study the sediment layers of the seafloor.
The expedition marked the first time anyone had used a remotely operated underwater vehicle to explore the seafloor beneath an ice shelf—and the first time anyone had investigated this specific area, according to Schmidt Ocean Institute.
“It’s quite unprecedented,” says Montelli in the statement.
The researchers also hope to uncover additional details about this unique type of ecosystem more broadly. What mechanisms are at play that allow deep-sea creatures to thrive in such a harsh environment?
In other parts of the deep ocean, surface nutrients sink to the seafloor and nourish the animals that live there. But no surface nutrients could have existed under the 500-foot-thick layer of ice, so something else must have been going on. The researchers suspect ocean currents or meltwater may be bringing nutrients to the region, but they’re not yet sure.
Large vase-shaped sea sponge
Scientists were surprised by how much life they found, including large sponges, anemones, worms, snails, fish and more.
In the future, they also want to return to the site to measure how the ecosystem changes. Those insights could prove useful in a warming world, in which more icebergs are breaking off in Antarctica and the Arctic.
“At a time when the West Antarctic Ice Sheet is melting at an alarming rate, understanding these dynamics and their impacts is particularly crucial,” says Svetlana Radionovskaya, a paleoceanographer and marine geologist with the British Antarctic Survey, in a statement.