Scientists believe that global warming has been affecting Caribbean corals for decades, weakening reefs and making them more susceptible to maladies like Stony Coral Tissue Loss Disease.

Several warming-related bleaching events have already occurred in the Caribbean, according to Dr. Shannon Gore, director of the Association of Reef Keepers.

Dr. Gore explained exactly what happens when temperatures are too warm for corals to survive.

Corals have a symbiotic relationship with an algae that lives in their tissue, she said. The algae photosynthesises and produces excess sugar which the coral uses to lay down calcium skeletons. At the same time, the algae gets a constant source of nutrients from the coral eating and producing waste.

But when sea surface temperatures get too warm, the algae begins to produce a chemical that is toxic to the coral, and so the coral spits the algae out. However, the coral can only last a couple of weeks without the algae, and if temperatures don’t decrease, the tissue dies and all that’s left is a skeleton.