Algae could ‘protect coral reefs from climate change’

A school of fish swims in the Coral Sea

Scientists have discovered a type of algae that could play a key role in protecting coral reefs against climate change. Coral reefs all over the world are being badly damaged as warming oceans gradually suck the life out of them.

But researchers have identified two species of algae which are able to adapt and survive the hotter seawater temperatures caused by global warming and could be used to boost the coral reefs’ defences.

“This is an important step forward in understanding how coral can handle global warming…It is encouraging to see that corals have mechanisms in place to adjust to high seawater temperatures,” said Cecilia D’Angelo, of the University of Southampton.

Changing their chemical make-up

The algae species – known as Cladocopium and Durusinium trenchi – are able to change their chemical makeup to survive warmer seas that can prove fatal to other coral-dwelling plants.

As such, their survival helps protect the coral from the warming ocean – protection that could be enhanced further through conservation measures to increase the algae’s presence on the corals.

The algae are already found in many of the world’s coral reefs, which stretch from the Pacific Ocean to the Indian Ocean, the Caribbean, the Red Sea and the Persian Gulf – but they could be present in much larger numbers.

Mutually beneficial relationship

The corals and the algae have a mutually beneficial relationship. The algae gain shelter, nutrients and carbon dioxide, which is needed for photosynthesis. In return, the algae produce oxygen and supply the coral with energy in the form of glucose, glycerol and amino acids, which are the products of photosynthesis.

The study is published in the journal Coral Reefs.

Previous study

The study is the second in recent months offering hope for the world’s beleagued coral reefs. In June, scientists identified more than a dozen areas where they are flourishing against the odds – a discovery that could provide valuable clues to protecting the others.

An international team of researchers found 15 coral reef “bright spots” where, despite facing similar pressures from fishing, disease, pollution and global warming as the others, they are doing better than might be expected.

These areas were typically found in the Pacific Ocean in places like the Solomon Islands, parts of Indonesia, Papua New Guinea and Kiribati, found the study of more than 2,500 reefs in and around 46 countries – and the key to their health was that they hosted more fish than comparable reefs faring less well.