Southeast Asia coral deaths 'the worst since 1998'

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International marine scientists are calling for the control of global carbon emissions after one of the largest coral deaths ever seen has hit Southeast Asia.

In the last six months many reefs have either died or are dying across the Indian Ocean and into the Coral Triangle - known as the 'Amazon rainforest' of the seas - following a bleaching event that extends from the Seychelles in the west to Sulawesi and the Philippines in the east and includes reefs in Sri Lanka, Burma, Thailand, Malaysia, Singapore, and many sites in western and eastern Indonesia.

This means that coral cover in the region could drop from an average of 50% to just 10%, and will take years to recover, affecting both local fishing communities and regional tourism industries.

Dr Andrew Baird ARC Centre of Excellence for Coral Reef Studies and James Cook Universities is quoted saying:

"It is certainly the worst coral die-off we have seen since 1998. It may prove to be the worst such event known to science. So far around 80% of Acropora colonies and 50% of colonies from other species have died since the outbreak began in May this year."

The bleaching event was caused by a large pool of super-hot water which swept into the eastern Indian Ocean region several months ago. By July, local divers recorded water temperatures of 34C, over four degrees higher than the average water temperature at this time of year.

The sudden rise of temperature shocked the corals causing them to shed the symbiotic algae that nourish them, thus losing their colour - this is known as "bleaching." If the corals do not regain their algae they eventually starve to death.

The Coral triangle is the richest region for corals on earth and relies on the areas around it to supply the coral spawn and fish larvae, this means that there are both direct and indirect effects of the die off, also affecting their ability to recover from future disturbance.

Dr Baird added: "The reefs of the region support tens of millions of people who make their living from the sea and so plays a vital role in both the regional economy and political stability. the bleaching is most severe, a high proportion of the people rely on fishing and tourism for their livelihoods. While it may take up to two years for some fish species to be affected by the loss of coral habitat, fisheries yields will decline and this combined with a drop in the number of SCUBA divers visiting could have major long-term effects on the local economy."

"My colleagues and I have high confidence these successive ocean warming episodes, which exceed the normal tolerance range of warm-water corals, are driven by human-induced global warming. They underline that the planet is already taking heavy hits from climate change - and will continue to do so unless we can reduce carbon emissions very quickly."