bleached corals

More than 60% of Maldives’ coral reefs hit by bleaching

bleached corals
Bleached coral seen at low tide on Hudhuranfushi Island, North Male atoll. Bleaching events are becoming more frequent and severe due to sea temperature change. Photograph: Simon McComb/Alamy

Scientific survey found all reefs had been affected by high sea surface temperatures, with up to 90% of coral colonies bleached in some areas

August 12, 2016 — More than 60% of coral in reefs in the Maldives has been hit by “bleaching” as the world is gripped by record temperatures in 2016, a scientific survey suggests. 

Bleaching happens when algae that lives in the coral is expelled due to stress caused by extreme and sustained changes in temperatures, turning the coral white and putting it at risk of dying if conditions do not return to normal.

Unusually warm ocean temperatures due to climate change and a strong “El Nino” phenomenon that pushes up temperatures further have led to coral reefs worldwide being affected in a global bleaching event over the past two years.

Preliminary results of a survey in May this year found all the reefs looked at in the Maldives, in the Indian Ocean, were affected by high sea surface temperatures. Around 60% of all assessed coral colonies, and up to 90% in some areas, were bleached.

The study was conducted by the Maldives Marine Research Centre and the Environmental Protection Agency, in partnership with the International Union for Conservation of Nature (IUCN).

It took place on Alifu Alifu Atholhu – North Ari Atoll – chosen as a representative atoll of the Maldives.

Dr Ameer Abdulla, research team leader and senior adviser to the IUCN on marine biodiversity and conservation science, said: “Bleaching events are becoming more frequent and more severe due to global climate change.

“Our survey was undertaken at the height of the 2016 event and preliminary findings of the extent of the bleaching are alarming, with initial coral mortality already observed.

“We are expecting this mortality to increase if bleached corals are unable to recover.”

The Maldives contains around 3% of the world’s coral reefs and the islands are considered particularly at risk of climate change because they are low-lying and threatened by sea level rises.

In Australia, more than a fifth of the Great Barrier Reef is estimated to have died as a result of the worst mass bleaching event in history. In Kiribati in the Pacific, as much as 80% of the coral is dead.

guardian_64  by Press Association | The Guardian