Mass bleaching of Sri Lanka coral reefs


Higher than normal ocean temperatures off Sri Lanka’s coast is threatening to damage the best coral reefs in the island, according to surveys done by marine scientists of the National Aquatic Resources Research and Development Agency (NARA).

“Underwater surveys shows widespread bleaching or whitening along the reefs, especially in shallow depths (of less than 10 meters) in the south and south west coast and also reported in Jaffna and Bar Reef in Kalpitiya,” a statement said.

NARA scientists diving on the reefs said huge areas of previously pristine reefs they have seen in Unawatuna, Weligama, Mirissa and Polhena are being turned into barren white.

All signs point to a repeat of a similar bleaching event in 1997/1998 which saw over 50 per cent of some reefs in Sri Lanka being destroyed, NARA said.

“Coral bleaching events have been increasing in both frequency and extent worldwide in the resent past years. Global climate change may play a role in the increase in coral bleaching events.”

NARA said the intolerable heat experienced over the past months is being blamed for the coral bleaching, which experts fear could be worse than in 1997/1998.

According to Mark Eakin, co-ordinator of the National Oceanic and Atmospheric Administration's Coral Reef Watch, the bleaching is very strong throughout south east Asia and the central Indian Ocean.

“Increased ocean temperatures due to climate change, combined with the warming effects of an El Niño pattern are driving temperatures to record levels and threatening to severely deplete the coral reef ecosystems that support fish habitats, shoreline protection and coastal economies mainly through fisheries and tourism,” he said.

Many of the reefs affected by the 1998 El Niño have made at least partial recoveries, NARA said.

“However, even when reefs do recover, old growth corals that may have taken centuries to mature are often replaced with faster growing species that quickly colonize large areas, homogenizing the ecosystem.”

Bleaching of coral reef may result in changes in diversity, with more sensitive coral species gradually being replaced by more tolerant ones, reducing the biodiversity of the coral reef.
(Colombo/June 11 2016)

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