How corals can be ‘trained’ to cope with heat stress from climate crisis

A new study has been called a “glimmer of hope” for corals, who are vulnerable to damage as oceans get hotter and extreme weather becomes more frequent due to the climate crisis.

US scientists say they have found a way to improve the “stamina” of the organisms when faced with heat stress - and so boost their chances of survival in a warming world.

This is good news for corals, who have been faced with an onslaught of stark warnings over their fate in the climate crisis - which the University of Miami researchers called the “greatest threat” to reefs.

Scientists have previously warned limiting global temperature rises to 1.5C - the target set by the Paris Agreement - would be “catastrophic” for them due to damage from heat stress.

In the recent Intergovernmental Panel on Climate Change report, considered the leading authority on climate science, even 1.2C warming in the near-term would lead to coral reef bleaching - when they turn white and risk dying.

The new research saw corals placed in different conditions in a laboratory: one group was subjected to fluctuating temperatures - going betwween 28C and 31C twice a day - while another was kept at a stable 28C for three months.

Those which experienced varying temperatures succumbed to bleaching more gradually than ones kept at 28C, as well as others in a control group.

While other studies have looked at conditioning corals to stressful conditions in the past, this is the first to look at the effect of long-term fluctuating temperatures.

“This ‘training’ regime is akin to an athlete preparing for a race,” Allyson DeMerlis, the study’s lead author, said.

She added: “Our findings bring a glimmer of hope to the uncertain future of corals, as we identified a treatment in which we can enhance their tolerance to heat stress.”

These solutions are essential to ensuring coral reefs survive in the climate crisis, according to another author of the study published in journalCoral Reefs.

Ian Enochs said: “We have unfortunately reached the point where active intervention and restoration are necessary to ensure that valuable coral reefs are able to persist for generations to come.”

The coral scientist at the National Oceanic and Atmospheric Administration added: “We want to increase the efficiency and efficacy of these efforts, and ultimately ensure that the corals that are placed back out on a reef have the greatest chance of enduring the stressful conditions they will face in the future.”