Heat stress causes bleaching in two-thirds of world's coral reefs, alarms report

Approximately two-thirds of the world'scoral reefs, underwater ecosystems which are crucial for so many reasons, are getting bleached due to severe heat stress, according to the latest report by the US National Oceanic and Atmospheric Administration (NOAA).

Coral reefs are often referred to as the "rainforests of the sea" and are incredibly biodiverse andimportantto marine life.While protecting and preserving these fragile ecosystems is essential to supporting coastal economies and ensuring the health of our oceans,the combined effects of climate change and the El Nino climate pattern which have driven ocean temperatures to record highs have led to these bleaching events.

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NOAA's Coral Reef Watch coordinator Derek Manzello expressed grave concern during a recent briefing.

"I am very worried about the state of the world's coral reefs," Manzello said, adding, "We are seeing (ocean temperatures) play out right now that are very extreme in nature".

Coral bleaching occurs when corals expel the algae living within their tissues, which are called zooxanthellae. These algae provide corals with food through photosynthesis and give them their vibrant colours.

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However, bleaching by heat stress is expelling the algae and rendering coral reefs pale, leaving them starved and sick.

Dozens of countries face mass coral reefs bleaching

Reports from scientists have revealed mass bleaching occurrences in over 62 countries and territories. The 2014-2017 event is still considered the worst on record due to its severity and persistence. However,2023-24 could soon take over as being the worst coral reefbleaching event.

Recent assessments from April 2024 have shown alarming levels of coral mortality. Between 50 per cent and 93 per cent bleaching observed in certain areas like Huatulco, Oaxaca, in the Mexican Pacific.

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The Atlantic Ocean, in particular, has witnessed a significant impact. Nearly 100 per cent of its reefs there are experiencing bleaching-level heat stress over the past year.

Manzello described the situation in the Atlantic as "off the charts."

Manzello warned that "this has never happened so early in the year before.""El Nino is dissipating, but the ocean is still anomalously hot. It won't take much additional warming to push temperatures past the bleaching threshold," he added.

(With inputs from agencies)