Antarctic species suffering from climate change

10 October 2011
Posted by Chris Smith.

David Barnes and his colleagues at the British Antarctic Survey have found that the sea-floor ecosystem of an area of the West Antarctic Peninsula is suffering from theeffects of climate change. The team were studying tiny organisms called bryozoansthat live on the sea floor, as a marker of the ecosystem's response to scouring byicebergs.

They also studied the duration of the skin of 'fast ice' that forms on thesea surface every winter. This skin helps to protect the shallower waters from beingscoured by ice flows, so if there is less ice in a particular year due to increasedtemperatures, then scouring of the seafloor communities will increase. They foundthat over the last 25 years, the duration of the fast ice has decreased, with now five days fewer ice coverage. Iceberg

There was also worrying data from looking at the bryozoans. Since 1997, the chance of a bryozoan colony reaching sexual maturity, around 2 years old, has halved. Obviously if they are killed before they can breed, this will have a damaging effect on the species. Plus benthic species like the bryozoans are important for carbon sequestration. Reduced sea ice coverage can mean an increase in growth, but the authors suggest that this will be counteracted by the damaging effects of ice scouring.

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