Hope Beneath the Surface

The world’s coral reefs are under pressure from rising sea temperatures. Data collected by Coral Reef Watch from reefs in 82 countries and territories shows how rapidly the damage is spreading across the Pacific, Atlantic and Indian oceans. Countless reefs have already been weakened or killed.

In Genoa, Fabio Mattioli is trying to work out whether some corals can be taught to withstand the heat.

Mattioli, 54, a natural scientist and curator of the tropical department at the Acquario di Genova, oversees an internationally recognised coral-breeding programme. His department is home to 2,700 specimens from 75 species, kept in 14 aquariums and two large tanks. Some were rescued after being seized by customs officials.

“We make only a very small contribution to saving the corals compared with the scale of the disaster that is coming,” Mattioli says.

His team is nevertheless testing the limits of what corals can endure. At 28C, the researchers examine which enzymes the animals produce in response to heat stress and whether they can adapt. The temperature is then gradually raised to 30C and the tests repeated.

This is around the point at which coral bleaching normally begins. Heat-stressed corals expel the microscopic algae known as zooxanthellae that live inside their tissues. The algae provide nutrients and give the corals much of their colour. Without them, corals may eventually starve and die.

The researchers are therefore breeding the corals that appear best able to withstand the heat.

Edith Canepa, a biologist and one of eight research assistants in the department, demonstrates how fragments are propagated. She cuts a branch from a coral colony, fixes it to a piece of stone with industrial adhesive and returns it to the tank. Other species are attached to the substrate or held in place with small dowels.

“In the long term, the glue and the fastenings have to be biodegradable,” she says. The team is experimenting with organic resins.

The work in Genoa is also being taken beyond the laboratory. Together with the University of Milano-Bicocca, the department is involved in a research project in the Maldives, the Marthe Center Lab, where coral gardens are being replanted with the help of local residents and tourists.

Canepa has seen the results for herself. The transplanted corals are growing well, she says. But rebuilding an entire reef is another matter.

“It would be a Herculean task,” she says, even if every coastal resident and tourist could be trained to help.

Still, there is something to be said for beginning with a single fragment of coral, fixed to a stone in a tank in Genoa.

“We have made a start.”