The Great Barrier Reef has lost half its corals

(CNN) – Australia’s Great Barrier Reef has lost 50% of its coral population in the last three decades, a new study by a major driver of reef disturbances with climate change.

Researchers at the ARC Center of Excellence for Coral Reef Studies in Queensland, northeastern Australia have evaluated the size of mung bean communities and their colony based on the length of the Great Barrier Reef between 1995 and 2017, reducing almost all coral populations Does.

Coral reefs are some of the most vibrant marine ecosystems on the planet – between a quarter and a third of all marine species rely on them at some point in their life cycle.

The Great Barrier Reef is the largest coral reef in the world, spanning approximately 133,000 square miles and contains more than 1,500 fish species, 411 species of hard coral and dozens of other species.

“We found that the number of small, medium and large corals on the Great Barrier Reef has declined by more than 50% since the 1990s,” said a distinguished professor at the ARC Center of Excellence for Core-Reef Studies, co-author Terry Hughes reported. in a statement.

Reefs are fundamental to the health of marine ecosystems – without them, ecosystems collapse, and marine life dies.

The Great Barrier Reef covers approximately 133,000 square miles.

Francois Gohier / VWPICS / Universal Image Group / Getty Images

The coral population size is also considered important when it comes to coral fertility.

“A vibrant coral population has millions of small, baby corals as well as many large ones — which produce large larvae,” said Andy Dietzel, a doctoral student at the ARC Center of Excellence for Coral Reef Studies. in a statement.

“Our results show the ability of the Great Barrier Reef to recover – its resilience – is compromised compared to the past, as it has fewer children, and fewer breeding adults,” he said.

Experts found that shallow and deep-water coral species declined both, but experts found that branches and table-shaped coral, which provide habitat for fish, were the most affected by large-scale bleaching events in 2016 and 2017. More were affected, which began with record breaking temperatures.

This file photo, taken on 22 September 2014, appears to be floating through the coral on Australia's Great Barrier Reef.

The authors of the report warn that climate change is accelerating the frequency of “reef disturbances”.

William West / AFP / Getty Images

Warm ocean temperatures are the main driver of coral bleaching, when the coral turns white as a stress response to water that is too hot. Bleaching does not kill coral immediately, but if temperatures remain high, coral will eventually die, destroying a natural habitat for many species of marine life.

Tuesday’s study revealed large-scale bleaching events in 2016 and 2017, with worsening of coral colonies in the northern and central Great Barrier Reef.

The Great Barrier Reef has suffered several large-scale bleaching events over the past five years, and experts said the southern part of the reef was also exposed to record-breaking temperatures in early 2020.

“We used to think that the Great Barrier Reef is protected by its sheer size – but our results show that the world’s largest and relatively well-protected reef system is rapidly compromised and degraded,” Hughes said.

The authors of the report warned that climate change is accelerating the frequency of “reef disturbances” like ocean heat.

“There is no time to lose – we must sharply reduce greenhouse gas emissions,” the report published in the proceedings of the Royal Society magazine, the report’s authors warn in the paper.

Helen Regan of CNN contributed to this report.


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