(Reuters) — Coral reefs in the Red Sea’s Gulf of Aqaba are able to tolerate rising sea temperatures, which could mean they could be used to reseed dying reefs elsewhere in the world, according to a new study.
As sea temperatures rise as a result of global warming, coral reefs are deteriorating on a massive scale.
When the seawater is too warm, coral expels the algae on which it depends, causing calcification and turning the coral white. Scientists warn that if water temperatures do not drop, coral reefs will die as a result of bleaching.
Researchers from the Swiss Federal Institute of Technology (EPFL), the University of Lausanne, Bar Ilan University and the Interuniversity Institute of Marine Sciences undertook the first detailed physiological assessment of coral specimens taken from the Gulf Aqaba.
They kept the specimens – of the Stylophora pistillata coral – in tanks where they were exposed to stressful conditions over a six week period.
“We expose these corals here to thermal ramping. That means we increase the temperature to resemble a future ocean and at the same time we also alter the pH of the sea water,” explained EPFL researcher Thomas Kruegel.
The temperatures and acidification of the water resemble what the researchers predict would be the summer conditions of the future in the Red Sea if local warming continues at the current rate of 0.4-0.5 degrees Celsius per decade.
The researchers found that the specimens from the Gulf of Aqaba were not affected by the changes.
“Most of the variables that we measured such as energy metabolism or building a skeleton were actually improved, which suggests actually that these corals are living under suboptimal temperatures right now and might be better prepared for future ocean warming,” said Krueger.
The scientists believe the coral in the Gulf of Aqaba is unique because it has evolved to have a high thermal tolerance due to the geography and history of the local environment.
They hypothesize that coral recolonized the Red Sea as sea temperatures rose at the end of the last Ice Age. The southern entrance represented a “thermal bottleneck” with temperatures rising as high as 32 degrees Celsius in the summer, allowing only coral with high thermal tolerance to move north.
The researchers hope that their discovery could mean that coral from the Gulf of Aqaba could be used to reseed damaged reefs such as Australia’s Great Barrier Reef, which is enduring a second year of unprecedented bleaching.
The Great Barrier Reef stretches 2,300 km (1,430 miles) along Australia’s northeast coast and is the world’s largest living ecosystem. It experienced the worst reported bleaching on record in 2016.
However, they warn that the hardy Gulf of Aqaba coral is just as vulnerable to environmental damage like pollution and urged the countries bordering the Gulf – Egypt, Israel, Jordan and Saudi Arabia – to create a program to protect it.