New hope that coral reefs could be revived after bleaching events

Coral bleaching on the Great Barrier Reef during a mass bleaching event in 2017.
Coral bleaching on the Great Barrier Reef during a mass bleaching event in 2017 (Getty)

‘Coral bleaching’ due to climate change poses a threat to reefs around the world - but could it be reversed?

A new study by Californian researchers offers hope that the damage of ‘bleaching’ might be reversible and that the reefs could be saved.

Corals receive some of their nutrients through a symbiotic relationship with photosynthetic algae which live inside their cells.

High ocean temperatures cause a breakdown in the symbiosis resulting in a 'bleached' coral that has expelled the algae.

If symbiosis is not initiated within a few weeks, the coral will starve to death.

Read more: World’s southernmost reef hit by coral bleaching

Bleached coral is a sign the reef is close to death. (Getty)
Bleached coral is a sign the reef is close to death. (Getty)

The study shines new light on the delicate relationship - finding that although photosynthesis by algae is a key part of the symbiotic relationship it is not required to initiate symbiosis.

The finding could lead to strategies that might prevent warmer oceans from breaking the symbiotic relationship between the two organisms and saving what remains of the world's coral.

Robert Jinkerson, an assistant professor of chemical and environmental engineering at UCR, and Tingting Xiang, an assistant professor of biological sciences at the University of North Carolina, led a team to create mutant Symbiodiniaceae algae - and use these mutants to investigate symbiosis with cnidarians

Co-lead author Joseph Russo said: "Time is of the essence regarding the protection of the coral reefs, and our hope is that these mutants will allow ourselves and others to increase the overall pace towards this goal.”

"Our study highlights the power of forward genetic approaches to probe cnidarian Symbiodiniaceae symbiosis and provides a promising platform to answer key questions in symbiosis and ultimately develop strategies to save corals," said Xiang.

A dead bleached coral reef. (Getty)
A dead bleached coral reef. (Getty)

Read more: Melting snow in Himalayas drives growth of green sea slime visible from space

A study found that coral reefs are expected to see huge changes in the water around them by the second half of this century.

The researchers found that 60% to 87% of the ocean is expected to experience multiple biological and chemical changes, such as increases in water temperature, higher levels of acidity and changes in oxygen levels, by the year 2060.

The rate of change is expected to be even higher, 76% to 97%, in very large marine protected areas such as Australia's Great Barrier Reef Marine Park and the Galapagos Marine Reserve in Ecuador.

"What we're looking at here is the potential extinction of a whole environment," said Watson, who specialises in marine social-ecological systems and understanding complex adaptive systems.

"In some places, the environments we have today are not going to exist in the future. We won't be able to go visit them or experience them. It is an environmental, cultural and economic loss we can't replace."

Watch: Florida scientists use human medicine to help save coral reefs