Six new species discovered beneath Antarctic seafloor after iceberg A-84 break-off

An international team aboard Schmidt Ocean Institute’s R/V Falkor (too), operating in the Bellingshausen Sea, rapidly altered their research plans to study an area that was, until January 2025, covered by ice.

On January 13, 2025, an iceberg roughly the size of Chicago—designated A-84—broke off the George VI Ice Shelf, one of the major floating extensions of the Antarctic Peninsula ice sheet. By January 25, a research team reached the newly exposed seafloor, becoming the first to study an area that had remained inaccessible to humans until now.

The expedition marked the first detailed, comprehensive, and interdisciplinary study of the geology, physical oceanography, and biology beneath such a large area once covered by a floating ice shelf. The calved ice measured approximately 510 km² (197 mi²), revealing an equivalent area of seafloor.

“We seized the moment, changed our expedition plan, and proceeded to observe what was happening in the depths below,” 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.

“We didn’t expect to find such a thriving ecosystem. Based on the size of the animals, the communities we observed have likely existed for decades, possibly hundreds of years.”

The vessel arrived at the area within a day. A submersible robot was lowered more than 1 000 m (3 281 feet) underwater to explore and livestream the region to scientists. Almost immediately, researchers began observing previously unseen lifeforms.

“The first thing we saw was a huge sponge with a crab on it,” said Esquete. “That was already quite surprising because one question we had was, ‘Will there be any life at all?’”

According to the institute, the remotely operated vehicle explored the seafloor for eight days. It also discovered large corals and additional sponges that were supporting species, such as icefish, giant sea spiders, and octopuses.

Esquete stated that researchers are now examining how the ecosystem has received enough energy to function. Dr. Jyotika Virmani, Executive Director of Schmidt Ocean Institute, suggested that ocean currents might be transporting nutrients to the area.

Since January, scientists have confirmed the existence of at least six new species, according to Virmani, with many more specimens yet to be analyzed.

Deep-sea ecosystems typically rely on nutrients from the surface slowly descending to the seafloor. However, these Antarctic ecosystems have been covered by 150 m (492 feet) of ice for centuries, isolating them from surface nutrients. Ocean currents can transport nutrients, and the team hypothesizes that this may be a mechanism sustaining life beneath the ice. The exact process enabling these ecosystems remains unclear.

The expedition was part of Challenger 150, a global initiative focused on deep-sea biological research, endorsed by the Intergovernmental Oceanographic Commission of UNESCO (IOC/UNESCO) as an Ocean Decade Action.

“The science team was originally in this remote region to study the seafloor and ecosystem at the interface of ice and sea,” said Virmani. “Being present when the iceberg calved from the ice shelf provided a rare scientific opportunity. Such serendipitous events are part of the excitement of marine research, offering a chance to be the first to witness untouched environments.”

The team’s research into the newly discovered ecosystem is ongoing, Esquete said. They plan to return to the area in 2028.

References:

¹ Thriving Antarctic Ecosystems Found in Wake of Recently Detached Iceberg – Schmidt Ocean Institute – March 20, 2025