This phenomenon of dieback is caused by the rise in the temperature of the water, which causes the expulsion of the symbiotic algae giving to the coral its bright color.
Le Monde with AFP
The great Australian coral barrier undergoes a “large bleaching” caused by oceanic temperatures above average, on Friday, March 25, the authority responsible for this reef. Aerial surveillance flights have seen a discoloration of the coral, “confirming a vast phenomenon of laundry, the fourth since 2016”, according to the authority of the Marine Park of the Great Barrier of Coral (GBRMPA), responsible for the management of the biggest coral reef system in the world.
The corals suffered despite a phenomenon of refreshment of the southern summer by the Niña, cyclical climate phenomenon – contrary to that of El Niño – which translates into a cooling of the Pacific Ocean.
This phenomenon of decaying the Great Coral Barrier is caused by the rise in the temperature of the water – consequence of global warming – which causes the expulsion of symbiotic algae giving the coral its bright color.
Although bleached corals are stressed, they can still recover if the conditions become better, however, highlighted the GBRMPA: “Weather conditions for the next two weeks are crucial to determine the extent and severity of the Bleaching corals in the marine park. ”
” The colors replaced by a ghostly white “
The study of this extensive whitening phenomenon was published four days after the United Nations began the inspection of the Great Barrier to assess whether the site, classified as World Heritage, is protected from climate change. .
“The bright and appreciated colors of the Great Coral Barrier are being replaced by (…) a ghostly white,” lamented Martin Zavan, a Greenpeace Australia activist. He urged the government to show areas affected by this phenomenon to the UN mission that currently inspects the reef rather than the picturesque areas that have not been affected. “If the government really wants to allow the United Nations mission to be a complete idea of the State of the reef, it must take the mission in the north and the center of the reef,” said Zavan.
The objective of the mission of UNESCO aims to assess whether the Australian Government acts sufficiently against the threats to the Great Barrier of Coral, before the World Heritage Committee determines in June if it is necessary to classify it. “in danger”.
In July 2021, the World Heritage Committee decided not to classify the site “at risk”, to the general surprise and against the recommendation of UNESCO . Australia has launched a “reef 2050” protection plan, with billions of dollars, after the United Nations threatened in 2015 to decommission the site.
The large coral barrier houses some 1,500 species of fish and 4,000 types of molluscs. In recent years, it has also been affected by several cyclones, in addition to being threatened by agricultural runoff and by purple acanthaster, a coral starfish.