The 2,300 km (1,429 mile) reef is in its fifth mass bleaching event since 2016, with aerial surveys showing the extent of the damage.
Australia’s Great Barrier Reef, which stretches some 2,300 km off the country’s northeast coast, is experiencing the worst bleaching event on record.
The extent of the bleaching was revealed by aerial surveys after the government agency responsible for managing the reef confirmed early last month that the reef had been affected by its fifth major bleaching event since 2016.
Bleaching, when corals expel the colorful microscopic algae that live in their tissues in an attempt to survive, was triggered by an increase in water temperature that began in December last year.
“This prolonged exposure to heat has caused massive bleaching of coral reef communities observed across all three regions of the Great Barrier Reef,” the Great Barrier Reef Marine Park Authority said in an update on Wednesday. on its website. “The combination of aerial and in-water surveys in 2024 confirms a mass bleaching event, with widespread and extreme bleaching observed on several reefs in the 3
regions of the Great Barrier Reef Marine Park.
The agency said it surveyed a total of 1,080 reefs and that 79% of them showed some level of coral bleaching. Some 49 percent of the reefs surveyed had high to extreme levels of bleaching, the report said, with the worst affected areas located in the central and southern parts of the World Heritage-listed reef.
In the southern region, heat stress was the highest recorded by the National Oceanic and Atmospheric Administration satellite since it began operations in 1985, the agency said. In this area, bleaching prevalence ranged from high (31 to 60 percent of bleached coverage) to extreme (more than 90 percent of bleached coverage). Only 3 percent of the reefs surveyed were not bleached.
Coral reefs are living organisms and the Great Barrier Reef is considered one of the most species-rich habitats in the world. It is home to hundreds of species of corals, 1,500 species of fish and 4,000 different molluscs.
Reefs also provide protection to coastal communities and are natural carbon sinks. Climate change is the the biggest threat to their survival because of their sensitivity to heat.
“Only the strongest and fastest possible actions to reduce global greenhouse gas emissions will reduce the risks of heat stress on the reef and limit the impacts of climate change on the Great Barrier Reef,” said the marine park authority.
Corals can recover from bleaching and the agency said the full impact of the event would not be known for some time. He added that investigations into the water would continue.
