Researchers studying the ocean floor beneath a recently calved iceberg have made a groundbreaking discovery, challenging existing theories about the impact of massive ice chunks on their surrounding environment.

A team of scientists investigated the seafloor in an area that was previously covered by the enormous A-84 iceberg, which is comparable in size to the city of Chicago. To their surprise, they found a diverse and thriving community of organisms on the seafloor, located beneath the spot where the iceberg was once attached to an ice shelf connected to Antarctica.

“The discovery of such a vibrant and thriving ecosystem was unexpected,” said Patricia Esquete, co-chief scientist of the expedition and a researcher at the University of Aveiro in Portugal, in a statement released by the British Antarctic Survey online. “Based on the size of the animals, it appears that these communities have been present for decades, possibly even centuries.”

With the 197-square-mile (510-square-kilometer) iceberg no longer obstructing their view, the team was able to explore the seafloor at depths of 4,265 feet (1,300 meters) using the remotely operated vehicle (ROV) SuBastian. Their findings included large corals and sponges that supported a variety of other species, such as icefish, giant sea spiders, and octopuses.

The research team was aboard the Schmidt Ocean Institute’s R/V Falkor (too), a 363-foot-long (111-meter) vessel that has made numerous significant discoveries about life on the ocean floor. The vessel has previously mapped unexplored areas of the seafloor and even captured footage of intimate octopus breeding grounds.

Prior to the iceberg’s calving, the seafloor beneath the ice shelf was cut off from the nutrient-rich surface waters, making it difficult for organisms to survive. The team hypothesized that ocean currents play a crucial role in sustaining life beneath the ice sheets. Additionally, they collected data on the larger ice sheet, which is shrinking at an alarming rate, posing a significant threat to the animals that inhabit the area beneath it.

“The loss of ice from the Antarctic Ice Sheet is a major contributor to global sea level rise,” said Sasha Montelli, co-chief scientist of the expedition and a researcher at University College London, in the same statement. “Our research provides critical context for understanding these changes and improving our ability to predict future changes, which can inform policy decisions. As we continue to analyze the data, we are likely to make new discoveries.”

Although the disappearance of the ice shelf is a cause for concern, it also presents scientists with a unique opportunity to explore an area that was previously inaccessible. The ROV SuBastian and R/V Falkor (too) are likely to make further discoveries about the extreme environments that support life, before their expeditions come to an end.