What Lies Beneath

In January, an iceberg the size of Chicago broke off from one of the vast floating glaciers attached to the Antarctic Peninsula, exposing a portion of the seafloor that had never been seen before. 

Excited by the opportunity, a team of researchers on board the Schmidt Ocean Institute’s research vessel R/V Falkor (too) working in the Bellingshausen Sea off Antarctica quickly shifted gears and rushed to the site to explore the geology and biology of the newly exposed depths of up to 4,000 feet below sea level. 

They were stunned by what they found.  

“We didn’t expect to find such a beautiful, thriving ecosystem,” said expedition co-chief Patricia Esquete in a statement. “Based on the size of the animals, the communities we observed have been there for decades, maybe even hundreds of years.” 

Little is known about what lies beneath Antarctica’s floating ice shelves, researchers say. In 2021, British Antarctic Survey researchers first reported signs of bottom-dwelling life beneath the Filchner-Ronne ice shelf in the Southern Weddell Sea. 

After the iceberg, known as A-84 and with an area of 209 square miles, broke off, the Schmidt Ocean Institute’s remotely operated vehicle, ROV SuBastian, was sent to the ocean floor for eight days. It exposed flourishing ecosystems: Researchers identified large corals and sponges supporting a range of marine life, like icefish, giant sea spiders, and octopus. 

Because of the significant biomass and biodiversity of the ecosystem observed, the team believes they have discovered new species as well. 

Deep-sea ecosystems generally receive nutrients from the surface that slowly reach the seafloor, but these Antarctic ecosystems have been buried by around 500 feet of ice for centuries and received nothing from the surface. However, ocean currents also move nutrients, and researchers believe these currents may have played a role in sustaining life beneath the ice, even if scientists don’t exactly understand how. 

The discovery of the rich biodiversity offers new insights into how ecosystems function beneath floating sections of the Antarctic ice sheet. The newly exposed Antarctic seafloor also allowed researchers to gather critical data on the past behavior of the larger Antarctic ice sheet, which has been shrinking and losing mass over the last few decades due to climate change. 

“The ice loss from the Antarctic Ice Sheet is a major contributor to sea level rise worldwide,” said expedition co-chief Sasha Montelli in the statement. “Our work is critical for providing longer-term context of these recent changes, improving our ability to make projections of future change – projections that can inform actionable policies. We will undoubtedly make new discoveries as we continue to analyze this vital data.”