Coral bleaching, like the one seen around Lizard Island on Australia’s Great Barrier Reef, occurs when water temperatures are too high.
A global coral bleaching event that began last year has quickly become the largest in history, with the area of affected coral reefs continuing to expand, according to a U.S. government agency.
“About 77% of the world’s coral reef areas experienced bleaching-level heat stress from early 2023 to October 10, 2024,” Derek Manzello of the National Oceanic and Atmospheric Administration (NOAA) told AFP on Friday. ” he said.
He said the ongoing bleaching event – the fourth since 1998 – had surpassed the previous record of 65.7% in half the time and was “still increasing in scale”.
Corals are marine invertebrates made up of individual animals called polyps.
They have a symbiotic relationship with algae that live within their tissues and provide their primary food source and attractive color.
When water temperatures are too high, such as during the heat wave that hit areas from Florida to Australia in the past year, corals expel algae and turn white, a phenomenon called “bleaching,” exposing corals to disease. be at risk of death. off.
The last record was set during the third global bleaching event, which lasted from 2014 to 2017, following previous events in 1998 and 2010.
NOAA’s heat stress monitoring is based on satellite measurements from 1985 to the present.
Manzello said NOAA has confirmed reports of large-scale coral bleaching from 74 countries or territories since February 2023.
“This includes locations in the Northern and Southern Hemispheres of the Atlantic, Pacific and Indian Oceans,” he told AFP by email.
About 850 million people around the world depend on coral reefs for food, jobs and to protect coastlines from storms and erosion, according to the nonprofit organization WWF.
This ecosystem is a haven for marine life and is home to more than a quarter of all marine life.
© 2024 AFP
Source: Biggest Global Coral Bleaching Event in History: U.S. Government Agency (October 18, 2024) from https://phys.org/news/2024-10-global-coral-event-biggest-agency.html Retrieved October 18, 2024
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