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Global coral bleaching may be ending, says US agency

A ranger takes photographs and notes during an inspection of the reef's condition in an area called the 'Coral Gardens' located 80 kilometers north-east from the town of Bundaberg in Queensland, Australia, June 11, 2015. Photograph: (Reuters)

WION Web Team New Delhi, Delhi, India Jun 20, 2017, 05.39 AM (IST)

Coral reef bleaching may be easing after three years of high ocean temperatures, the longest such period since the 1980s, the National Oceanic and Atmospheric Administration (NOAA) said Monday. If they do in fact ease, it will reverse a worrying and important trend.

But a UNESCO draft report also says that in this same three year period 75 per cent of world heritage coral reefs have already been exposed to stress from warmer waters that causes bleaching, ABC reports.

The NOAA brought good news, but the UNESCO report may dampen that. It says, "Coral mortality during the latest global-bleaching event most likely has been the worst ever observed, including at world heritage property reefs."

If coral bleaching is indeed easing up, hopefully it's not too late.


What is coral bleaching and why does it matter?

Basically, when coral dies, it bleaches. Healthy coral reefs protect shores from storms and offer habitats for fish and other marine life, including ecologically and economically important species.

However, after corals die, reefs quickly degrade and the structures that corals build erode. While corals can recover from mild bleaching, severe or long-term bleaching is often lethal, experts say.

Early in 2017, the rise in water temperature caused significant bleaching in the Great Barrier Reef in Australia for the second consecutive year and also in American Samoa, which was severely affected in 2015.


What's new?

NOAA experts said satellite data and other analysis showed widespread bleaching was no longer occurring in all three ocean basins -- Atlantic, Pacific and Indian -- "indicating a likely end to the global bleaching event".

NOAA scientists said they will closely monitor sea surface temperatures and bleaching "over the next six months to confirm the event's end".

Since 2015, all tropical coral reefs have seen above-normal temperatures, and more than 70 per cent experienced prolonged high temperatures that can cause bleaching. 

US coral reefs were hit hardest, with two years of severe bleaching in Florida and Hawaii, three in the Mariana Islands, and four in Guam, according to the NOAA.

(With inputs from AFP)


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