When a colossal iceberg broke free from Antarctica, scientists found something staggering beneath it

When a colossal iceberg broke free from Antarctica, scientists found something staggering beneath it

With the help of a remotely operated vehicle, the researchers discovered a breathtaking world hidden under the ice for centuries.

Published: March 20, 2025 at 3:50 pm

A team of international scientists aboard the Schmidt Ocean Institute’s research vessel, R/V Falkor (too) have shared a remarkable set of images and videos from a section of Antarctic seafloor that had been concealed beneath ice for centuries.

The shots were taken on a mission to explore the freshly exposed seabed left behind by the enormous A-84 iceberg, which dramatically broke away from the George VI Ice Shelf on 13 January 2025.

Measuring a staggering 510 square kilometres – roughly the size of Chicago – the iceberg’s sudden departure revealed a vast and previously inaccessible underwater world.

Join the expedition team as they discover a hidden world beneath the ice/Schmidt Ocean Institute (SOI)

A thriving and unexpected ecosystem

Armed with cutting-edge technology, including the remotely operated vehicle (ROV) SuBastian, the scientists embarked on an eight-day, deep-sea survey, plunging to depths of up to 1,300 metres.

What they found was nothing short of astonishing – an abundant and vibrant ecosystem flourishing in total darkness beneath the ice.

“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,” says expedition scientist Dr. Patricia Esquete.

"We didn’t expect to find such a beautiful, thriving ecosystem. Based on the size of the animals, the communities we observed have been there for decades, maybe even hundreds of years.”

Phantom jelly
A giant phantom jelly is documented in the Bellingshausen Sea off Antarctica, at an area where the shelf break and slope are cut by several underwater gullies/Credit: ROV SuBastian, Schmidt Ocean Institute

Corals and sponges played host to a variety of marine life, including icefish, huge sea spiders, octopuses and even a giant phantom jelly, a species of jellyfish that can grow up to a metre wide, while its four ribbon-like oral arms can measure more than 10 metres in length.

The team suspects they may have discovered several species new to science, offering a fresh perspective on life beneath Antarctica’s floating ice shelves.

Falkor Too Antarctica icebergs
Research vessel Falkor (too) manoeuvres around icebergs while conducting research in the Bellingshausen Sea off Antarctica/Alex Ingle, Schmidt Ocean Institute

Rethinking life beneath the ice

Until recently, little was known about the organisms residing beneath Antarctica’s vast ice shelves. The discovery of such a biodiverse ecosystem presents new mysteries – how do these creatures survive in a place completely cut off from sunlight and the usual food sources?

Deep-sea communities typically depend on organic material sinking from surface waters, yet this region had been entombed beneath 150-metre-thick ice for centuries, say the researchers.

The team hypothesises that ocean currents could be transporting essential nutrients, sustaining life in this hidden world.

Iceberg map
Satellite imagery from 19 January 2025 showing where the iceberg calved from George VI Ice Shelf in the Bellingshausen Sea/NASA Worldview application

Unlocking climate secrets

Beyond its biological wonders, the expedition is yielding critical insights into Antarctica’s past and future. The team, who are investigating geological clues left by the retreating ice sheet, say that understanding these patterns is crucial for predicting future ice loss and its impact on rising sea levels worldwide.

“The ice loss from the Antarctic Ice Sheet is a major contributor to sea level rise worldwide,” says expedition scientist Sasha Montelli.

"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 analyse this vital data.”

The team deployed autonomous underwater gliders to measure how glacial meltwater is influencing the region’s chemistry and ocean currents. Preliminary findings suggest heightened biological productivity and a significant influx of meltwater from the retreating ice shelf.

Periphylla predation
A helmet jellyfish drifts through the deep with tentacles splayed/Credit: ROV SuBastian, Schmidt Ocean Institute

This mission forms part of Challenger 150, a UNESCO-endorsed global initiative dedicated to deep-sea research. Schmidt Ocean Institute’s Executive Director, Dr Jyotika Virmani, says that "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.”

What else did they find?

An octopus rests on the seafloor
An octopus rests on the seafloor 1,150 metres deep/Credit: ROV SuBastian, Schmidt Ocean Institute
Sponge anemone
A large sponge, a cluster of anemones, and other life seen nearly 230 metres deep/Credit: ROV SuBastian, Schmidt Ocean Institute
Sponge and brittle stars
Brittle stars climb on a sponge, documented at a depth of 215 metres. This area, at the southeastern end of the Ronne Entrance off the Bellingshausen Sea, lost its ice shelf cover a few years ago/Credit: ROV SuBastian, Schmidt Ocean Institute
Solitary hydroid
A solitary hydroid drifts in currents approximately 380 metres deep. Solitary hydroids are related to corals, jellyfish and anemones, but do not form colonies/Credit: ROV SuBastian, Schmidt Ocean Institute
Krill
Krill swarm the lights of the Remotely Operated Vehicle (ROV)/Credit: ROV SuBastian, Schmidt Ocean Institute
A squid in the process of consuming a fish
A squid reveals a fish it is consuming at a depth of nearly 950 metres/Credit: ROV SuBastian, Schmidt Ocean Institute

Main image: an octopus rests on the seafloor 1,150 metres deep, in the Bellingshausen Sea off Antarctica/ROV SuBastian, Schmidt Ocean Institute

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