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A polar research expedition back in 2021 noticed something weird along the Fram Strait, a marine passage into the Arctic Ocean between Greenland and Svalbard. “Some of the icebergs were carrying unusually large amounts of debris and looked almost black from above,” as one biologist on the team, Melanie Bergmann, recalled in a statement.
This strange floating mystery has yielded a series of surprising discoveries along this Arctic region’s ocean floor. Researchers led by Germany’s Alfred Wegener Institute (AWI) and the Massachusetts-based Woods Hole Oceanographic Institution have documented thriving and entirely new ecosystems of soft coral, sea stars, “moss animal” bryozoa, anemones, sponges, and more. These emerging habitats on the chilly Arctic seabed, the team argues in its new study, appear to have been seeded by “dropstones” released from those craggy melting icebergs, creating the “hard substrate” surfaces that sedentary marine animals have long adapted to colonize.
But the research doesn’t just show how sensitive these Arctic climes have become to the impacts of climate change. Their work may soon also be of use to sea vessels needing better data to navigate around this increasing number of icebergs calved from melting glaciers—as well as from their dropstones, which pose risks in shallow waters if left uncharted.
Marine biologist Bodil Bluhm at UiT The Arctic University of Norway, who was not affiliated with the team’s research, described the finds to Nature as a real “‘wow’ example for how incredibly connected different parts of our planet are.”
Floating islands
Kirstin Meyer-Kaiser, a marine biologist at Woods Hole who collaborated on the new research, uncovered evidence that these dropstones have created new habitats via AWI’s network of 21 undersea sensor stations in the strait, the Hausgarten observatory. Satellite images of the rock-mottled icebergs, alongside deep-sea images from Hausgarten’s network, slowly helped identify which recently melted icebergs had left a trail of geological debris across the ocean floor as they vanished into the sea.
“Where previously there were only isolated stones of various sizes, we are now finding much larger accumulations, frequently in small groups. And with each new stone, a permanent settlement is created on the seabed,” Meyer-Kaiser said in a statement. “As a result, biodiversity in the deep sea is increasing.”
Chronological reconstructions via satellite traced the majority of these icebergs back to glaciers in northeastern Greenland and areas along the Russian High Arctic. But spotty satellite cover over those Russian glaciers, researchers said, prevented them from stating with confidence whether or not climate change has increased the creation of icebergs from those ice sheets.
The data collected above Greenland, however, was considerably better, allowing the team to chart how glacial formations scooped up myriad rock formations only to ship those stones out to sea as the melting ice slid and cracked apart.
The team also sampled stones from the Arctic’s emerging dropstone habitats, confirming that their mineralogical composition matched stones on these icebergs.
The tip about the iceberg
According to sea ice physicist Thomas Krumpen, the study’s lead author, there is value outside of marine biology and climate science in developing a better understanding of how icebergs are redistributing literal tons of rock from land to sea. His colleagues at AWI spun off a private company, in fact, Drift+Noise Polar Services, with the goal of sharing “timely sea ice information,” like iceberg hazards, with maritime customers.
“An increasing presence of icebergs in certain regions of the Arctic harbours considerable risks, for example for cruise ships and cargo ships, which are travelling in ever greater numbers in the ice or near the ice edge, as well as for exploration activities for oil and gas,” Krumpen explained.
“As fishing moves further north,” he added, “newly deposited stones in shallower areas could also become a risk for bottom trawling in the future.”
Not unlike the strait’s new soft coral habitats, these iceberg hazards are another example of the unintended ramifications of rising temperatures worldwide, Meyer-Kaiser noted: “Climate change impacts our world in ways we never even thought of,” she said.
