As rocks transform the seafloor, melting icebergs create new deep-sea habitats 2,500 meters below the Arctic Ocean |

Climate change is often dismissed as a story of ecological loss, but scientists have discovered unintended consequences occurring nearly 2,500 meters below the surface of the Arctic Ocean. As glaciers in Greenland and parts of the Russian Arctic become destabilized, more and more debris-laden icebergs are drifting across the Fram Strait before melting and releasing large amounts of rock to the seafloor. Known as rockfalls, these stones create a rare hard surface in the muddy deep-sea landscape. Researchers found that the newly deposited rocks are becoming settlements for sponges, sea anemones, corals and other marine life that need solid ground to survive. The discovery provides a striking example of how global warming is reshaping ecosystems in complex and often unexpected ways, altering the conditions for life in one of the most rapidly changing regions on Earth.

Arctic icebergs are transporting tons of rock to the seafloor

The findings come from a study, ‘Expanding Arctic iceberg traffic reshapes seafloor biodiversity,” by researchers at the Alfred Wegener Institute and the Woods Hole Oceanographic Institution. In a 2026 study published in the journal Nature, Krumpen, Meyer-Kaiser and colleagues discovered a climate-driven mechanism in which accelerated glacier calving increases deep-sea hard-bottom habitat. On June 14, 2021, during the RV Polarstern Expedition PS126, researchers visited the HAUSGARTEN Observatory (78°N). 35.66′ W, 3° 32.92′ W), which carried a large amount of dark rock-forming material. Scientists encountered an unusually dark iceberg in the Fram Strait between Greenland and Svalbard. Icebergs look almost black because they contain large amounts of shale, quartzite, gravel and rock scraped from the Arctic by glaciers.Melanie Bergmann, a marine biologist at the Alfred Wegener Institute, said:“We immediately realized that tons of rock were drifting in the Arctic Ocean, hundreds of kilometers away from any glaciers.”Subsequent analysis showed that the increase in iceberg numbers since the early 2000s was linked to instability in major glaciers in northeast Greenland and parts of the Russian Arctic. Reduced sea ice cover also allows icebergs to move more freely and melt faster, accelerating the transport of rock fragments to distant parts of the Arctic Ocean.The study further shows that Greenland’s tidewater glaciers are capable of transporting large amounts of sediment via iceberg drift, highlighting the scale of material movement throughout the Arctic marine environment.

new biodiversity hotspots Emerging on the Arctic seafloor

Photos collected from the long-term deep-sea observatory AWI-Hausgarten show a significant increase in the amount of rock accumulation on the seafloor between 2015 and 2017. The rocks can be traced directly to the melting icebergs overhead.For many deep-sea species, the arrival of these stones represents a rare ecological opportunity. Much of the Arctic seafloor consists of soft sediments, providing limited attachment points for organisms that rely on hard surfaces.Dr. Kirstin Meyer-Kaiser of the Woods Hole Oceanographic Institution explains:“Where before there were just isolated stones of varying sizes, we now find larger accumulations, often in small clusters. Each new stone forms a permanent settlement on the seafloor.”The researchers observed sponges, sea anemones, and other hard substrate specialists beginning to colonize these newly formed habitats. Each rockfall effectively acts as a miniature island, creating areas of biodiversity within an otherwise featureless environment.Commenting on the wider implications of the findings, Bodil Bluhm, a marine biologist at the Department of Arctic and Marine Biology at the Arctic University of Norway, described the study as:“This is a ‘wow’ example of how incredibly connected different parts of our planet are.”

Climate change is redrawing ecological boundaries beneath the Arctic Ocean

While the emergence of new habitats may benefit some species, scientists caution against viewing the phenomenon as a net ecological gain. Colonization of the deep ocean occurs extremely slowly, often taking decades. Researchers monitoring the same Arctic sites for 25 years recorded only a handful of new species colonizing the rocky surfaces.Furthermore, the processes that create these habitats are driven by accelerating climate change. Retreating glaciers, increased iceberg mobility, and the loss of Arctic sea ice continue to disrupt ecosystems across the region. Recent research shows that reduced sea ice also leads to nutrient imbalances that threaten the Arctic marine food web by reducing the supply of nitrates, a key resource for phytoplankton growth.The increase in icebergs also poses practical challenges. Researchers warn that increased iceberg traffic could increase the risk of shipping, offshore operations and future fisheries expansion into northern waters. Newly deposited stones may even pose a hazard to bottom trawling operations in shallower areas of the Arctic.As Meyer-Kaiser points out, shifts in Arctic seafloor communities are likely to continue in “slow motion” as warming reshapes glacier behavior and iceberg movement patterns. The discovery suggests that climate change is changing not just temperatures and ice sheets; It is physically reorganizing habitats and creating entirely new ecological niches in places that were once thought to be stable for thousands of years.