Coral connections threatened by climate change

A new offshore network of Marine Protected Areas could be disconnected by changes in weather associated with climate change. Coral populations on mountains beneath the sea hold the key to maintaining the links according to a study published in the Royal Society.

Deep-sea coral populations are linked by tiny, fragile larvae - ten would fit comfortably on the head of a pin - that drift and swim on the ocean currents, travelling hundreds of miles between suitable habitats. Dr Alan Fox, lead author of the study and a Daphne Jackson Trust Fellow said, "We can't track these particles in the ocean, but the little we know of their behaviour allows us to use computer models to simulate their epic journeys, predicting which populations are connected and which are isolated. In less well-connected networks, populations become isolated and cannot support each other, making survival and recovery more difficult."

The vulnerable cold-water coral Lophelia pertusa creates reefs that are hotspots of biodiversity. Today, Scotland's MPA network for Lophelia pertusa appears to be weakly connected, held together by a population on Rosemary Bank seamount, an undersea mountain off the west coast of Scotland. In years where the winds from the west are weaker during winter, the coral sites become isolated, with fewer links. Years with stronger winter westerlies produce a generally more connected network. A shift in average winter conditions in western Europe, as has been predicted by climate change models, could profoundly change the MPA network.

Cold-water corals also thrive on oil and gas platforms in the northern North Sea and west of Shetland. Results suggest these new populations bridge a gap in the network between corals in the Atlantic and along the coast of Norway. Professor Murray Roberts, co-ordinator of the ATLAS project, at the University of Edinburgh (Scotland, UK) said, "This study shows the unique role Scotland's seabed plays as a stepping-stone for deep-sea Atlantic species. By teaming up with researchers in Canada and the USA we will expand this work right across the Atlantic Ocean."

Reference: Royal Society Open Science. "Sensitivity of marine protected area network connectivity to atmospheric variability". Alan D. Fox, Lea-Anne Henry, David W. Corne, J. Murray Roberts 

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