Wildlife

Pacific corals in ‘worrying’ state

An in-depth probe along a 50,000-kilometre (31,000-mile) stretch of the Pacific found that up to 90 percent of some coral colonies around the Samoan islands had been bleached.

Around the Tuamotu archipelago, up to half of colonies are bleached, according to researchers on board the French research schooner Tara.

Around the islands of Tuvalu and Kiribati, sections of reef were dead by the time the team got there.

Even in more temperate waters to the north, reefs did not escape bleaching, said the team, with up to 70 percent of corals damaged around Okinawa, Japan.

Corals make up less than one percent of Earth’s marine environment, but are home to an estimated 25 percent of marine life. They act as nurseries for many species of fish.

Corals are tiny, invertebrate marine creatures that live in colonies and require algae to survive. The algae live on the corals, providing them with food and the bold colours that reefs are known for.

Corals “bleach” when they are stressed by environmental changes — due to ocean warming or pollution. They expel the algae and turn bone-white.

If the harm is not too severe, reefs can recover from a bleaching event, although this can take many years.