Great Barrier Reef might lose its ability to recover from bleaching

Pablo Tucker
October 14, 2020

Australia's Great Barrier Reef has lost more than half of its coral population in the last three decades, according to a new study, with climate change being the main driver of this loss.

Researchers at the ARC Centre of Excellence for Coral Reef Studies in Queensland, Australia, found that numbers were declining across the board. The destruction was particularly pronounced after the mass coral bleaching events that occurred between 2016 and 2017.

The Great Barrier Reef stretches across 2,300 kilometers down Australia's northeastern coast and is home to a wide variety of marine life, making it the world's largest coral reef ecosystem.

Coral reefs are essential to the health of marine ecosystems - without them, ecosystems would collapse and marine life would die.

"To know how coral populations will recover from these mass mortality events, we need to learn more about their composition", Andreas Dietzel, a coral researcher at the ARC Centre for Excellence for Coral Reef Studies at James Cook University who led the study, said in an email. Such a thing was mandatory because population researches are significant for comprehending the corals' capacity to breed.

Dr Dietzel said better data is urgently needed to see "how coral populations are changing and whether or not they can recover between disturbances".

We found the number of small, medium and large corals on the Great Barrier Reef has declined by more than 50 percent since the 1990s.

Lots of different types of corals in the reef have suffered.

"We used to think that the Great Barrier Reef was protected by its sheer size - but our results show that even the largest and relatively well-protected reef system in the world is increasingly vulnerable and in decline", said Professor Hughes.

The Great Barrier Reef, the largest coral reef in the world, covers almost 133,000 square miles and is home to more than 1,500 species, 411 species of hard corals and dozens of other species. What they discovered is a high reduction of coral populations.

The team were shocked by the huge decline after tracking the size of coral colonies along the length of the 133,000 sq mile reef between 1995 and 2017.

Authors of the study, published Wednesday in the journal Proceedings of the Royal Society B, warn "there is no time to lose" in ensuring carbon emissions are rapidly reduced.

The table-shaped and branching corals impart the structures that are crucial for reef inhabitants, for example, fish.

Larger species, such as branching and table-shaped corals, have been affected hardest, nearly disappearing from the far northern reaches of the reef, which experienced extreme heat stress during 2016 and 2017.

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