Friday, July 16, 2010

Red Sea coral growth 'to halt by 2070'

Mark Kinver in the BBC: A species of coral in the Red Sea could stop growing by 2070 if current warming trends continue, say scientists. A team of US researchers, using 3D technology, said that the rate of growth of Diploastrea heliopara had declined by 30% since 1998.

Rising sea surface temperature was already "driving dramatic changes" in the growth rate in the important reef-building organism, they observed. The findings have been published in the journal Science.

Co-author Anne Cohen, a research specialist at Woods Hole Oceanographic Institution (WHOI) in the US, explained that the team were able to measure the decline in growth by examining core samples from coral skeletons…."What is really cool is that everything that the colony has experienced in its life, which can be very long - these colonies can live four or five hundred years - is recorded in the skeleton," Dr Cohen explained. "It is recorded in annual growth bands, so we know exactly the year in which certain things happened."

The team collected "biopsies" from six colonies, which were then examined in a computerised tomography (CT) scanner.

…"We say in our paper that the upper growth rate has decreased by 30%, and the amount of calcium carbonate produced has decreased by 20% since 1998." Using the precise chronology provided by the CT scans, the team were able to compare coral growth with the sea surface temperature (SST) record. There was a critical temperature, 30.5C, above which the growth rate "basically plummetted"…

Coral in the Red Sea, but not the species discussed in the article, shot by Mahmoud Habeeb, Wikimedia Commons, USAID

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