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ScienceShot: In a Scrape

25 September 2011 1:00 pm
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British Antarctic Survey

Icebergs are scraping the sea floor of Antarctic waters more than ever, much to the detriment of bottom-dwelling creatures. The change comes because seasonal ice in the Antarctic doesn't last as long. Icebergs that break off from glaciers onshore are driven by winds and currents into shallow waters. At Rothera station on the West Antarctic Peninsula, the so-called "fast ice" that forms each winter lasts, on average, about 5 days less per year than it did a quarter-century ago, researchers from the British Antarctic Survey report online today in Nature Climate Change. Accordingly, the number of iceberg scrapes (see image) on the sea floor there has increased substantially. Only half as many colonies of Fenestrulina rugula, a filter-feeder that lives on rocks on the sea floor, survive to sexual maturity—the first demonstrable effect of climate change on the Antarctic seabed, the researchers say. Because about 80% of all marine species found around Antarctica live on or just beneath the sea floor, and because many reach sexual maturity more slowly than F. rugula does, the new finding bodes ill for ecosystems in the Antarctic shallows.

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