impact

Marine heatwaves kill corals quicker than previously thought

Australia’s Great Barrier Reef, a World Heritage site, is one of the most iconic coral reefs. But it’s in serious trouble due to bleaching: a new Australian Government report has officially downgraded the reef’s outlook from poor to very poor.

Coral bleaching is caused by global heating and leads corals to expel vital algae that live in its tissues, resulting ultimately in the death of these animals.

Now, according to scientists, there is an even more deadly threat—marine heatwaves—which destroy corals much more rapidly than previously thought.

A new study indicates that marine heatwaves should be considered a distinct biological phenomenon from bleaching events on coral reefs.

What happens is that in warmer water, within days, corals attract bacteria which speed up the breakdown of corals, says the study.

During the bleaching process, some corals produce fluorescent pigments that act as chemical sunscreens. Fluorescing is the reef’s beautiful last-ditch effort to save itself. Photo by the Ocean Agency/XL Catlin Seaview Survey, Coral Reef Image Bank  During the bleaching process, some corals produce fluorescent pigments that act as chemical sunscreens. Fluorescing is the reef’s beautiful last-ditch effort to save itself. Photo by the Ocean Agency/XL Catlin Seaview Survey, Coral Reef Image Bank