Melting Ice Battering Antarctic Shores, Killing Species

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Massive losses of sea ice in Antarctica have left icebergs free to roam for most of the year, with the out-of-control icebergs bashing Antarctic shores and killing species, new research has found.

According to the study, published in the journal Current Biology, boulders on the region’s shallow seabed that were once encrusted with a rich assemblage of organisms now mostly support just one species: a tough little marine creature with tentacles.

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David Barnes of the British Antarctic Survey and colleagues study the region, in part, to better understand how climate change is affecting the planet and ecosystems.

“The Antarctic Peninsula can be considered an early warning system—like a canary in a coal mine,” Barnes explained in a press release. “Physical changes there are amongst the most extreme and the biology considered quite sensitive, so it was always likely to be a good place to observe impacts of climate change—but impacts elsewhere are likely to be not too far behind.”

He added, “A lot of the planet depends on the near-shore environment, not least for food; what happens there to make it less stable is important.”

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For the study, he and his colleagues analyzed surveys of marine life along the Antarctic shore. They also went on frequent diving trips to observe iceberg changes and to do species population counts.

Several species were documented in the area in 1997. In 2013, only the pioneering Fenstrulina rugala, the aforementioned small critter with tentacles, was literally hanging on for dear life. While the other species have not gone extinct, they were in negligible numbers.

The scientists indicate that volatility to prior stable habitat, caused by the free-roaming icebergs bashing into boulders in the shallow seabed, is the culprit.

Even the tentacled creature, which Barnes and his colleagues describe as a “rather unremarkable suspension feeder,” didn’t seem too happy. F. rugala individuals were found to be competing with each other for Antarctic real estate.

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The researchers were surprised to see such population losses happen so quickly. Many scientists claim that climate change is expected to be a slowly evolving, long-term process. But in the Antarctic, things are moving much faster, and not for the better.

“Warming is likely to increase ice scour mortality and reduce assemblage complexity and could aid establishment of non-indigenous species,” the researchers concluded.

“We expect the deeper seabed to become richer in benthic (seafloor region) colonization with more ice shelf collapses and fast ice losses, but hard surfaces in the shallows are likely to become deserts dominated by rapidly colonizing pioneers and responsive scavengers—with little role for spatial competition or even predation in shaping the structure of such assemblages.”

Photo: A broken ice pack in Antarctica. Credit: Wikimedia Commons

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