Half of the corals in the Great Barrier Reef have disappeared

Australia’s Great Barrier Reef has lost 50 percent of its coral population in the past 30 years. Climate change played the most important role in this, new research confirms.

Researchers at Australia’s ARC Center of Excellence for Coral Reef Studies (CoralCoE) studied colonies along the full length of the reef and found that all declined between 1995 and 2017.

“The number of small, medium and large corals has declined more than 50 percent since the 1990s,” said Terry Hughes of CoralCoE. “This decrease is visible in shallow and deeper water, and in almost all species – but especially in table and branched corals. These species suffered the most from record temperatures that resulted in massive bleaching in 2016 and 2017. ”

Loss of habitat

The structures of branching and table corals attract reef dwellers such as fish. The loss of these corals also means loss of habitat, a declining fish population and lower productivity of coral reef fisheries.

“A vibrant coral population includes millions of small baby corals, as well as large corals. The large corals produce the most larvae, ”says lead author Andy Dietzel. “The study results show that the Great Barrier Reef is having more trouble recovering than it has in the past because there are fewer babies and fewer breeding adult corals.”

Frequent disruptions

Climate change has increased the frequency of disruptions, such as heat waves in the sea. The reef’s large size does not guarantee full recovery between different disturbances, according to Hughes. “Even the largest and relatively well-protected reef system in the world is increasingly damaged and declining.”

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