High water temperature

More and more corals in the Great Barrier Reef dead

The Great Barrier Reef off the north coast of Australia is home to a unique animal and plant world. However, studies have now revealed mortality rates of up to 72 percent. Among other things, rising water temperatures have contributed to this.

These lead to coral bleaching. This means that the corals then shed the microscopic algae living on them in order to survive. If the water temperatures remain high, the corals turn white and die. Surveys of twelve sub-reefs have found mortality rates of up to 72 percent, as the Australian Institute of Marine Science announced on Tuesday. In one northern section, a third of the hard corals are already dead.

"Limited resilience"
Although only a relatively small part of the entire reef was examined for the new report, it is feared that the rest of the Great Barrier Reef has suffered a similarly high level of coral mortality. The fast-growing species Acropora was particularly affected this year. "The damage is serious, the losses are huge," said study leader Mike Emslie.

The Great Barrier Reef could recover, but its "resilience" is "limited", said Richard Leck from the environmental protection organization WWF. The Australian government must reduce greenhouse gas emissions by at least 90 percent by 2023 compared to 2005. The country is one of the largest coal and gas exporters in the world.

The famous coral reef is 2300 kilometers long and is a UNESCO World Heritage Site. It consists of 2500 individual reefs. These in turn are among the largest and most complex ecosystems on earth, providing a natural environment for various plants and animals. More than 75 percent of all coral reefs worldwide are already under threat, for example due to overfishing, higher water temperatures and environmental pollution.