When water temperatures rise it causes a complex cascade of molecular signals leading up to the self-inflicted death of corals and expelling their symbiotic relationship with algae. The complicated process ends in what is known as “apoptosis,” or programmed cell-death. Cell-suicide occurs when an organism deliberately destroys weakened cells as a form of amputation to protect the entire organism.
In the past 30 years, there have been 7 major events of coral bleaching worldwide. The Great Barrier Reef alone has suffered 8 events since 1980, the worst in 2002 when 55% of the total reef area was affected.
The frequency of events like this is increasing on a global scale. I myself saw the devastation of coral bleaching stretching throughout the Greater and Lesser Antilles. I have hope for coral reefs, especially after diving in places like Fort Lauderdale Beach, just a few miles offshore and seeing how colourful the reefs were, despite all the tires everywhere (I will come back to this in another blog, about Osbourne Reef).
Studies working with Acropora corals (you may know them as elkhorn, staghorn or table coral), it was observed that the cascade begins at changes of ocean temperatures as little as 3o lower than those previously associated with coral bleaching.
Because of research like this, it has become clear that any subtle change in the environment can send corals quickly packing the bags of their zooanthellae counterparts to protect themselves.
Scientists believe that after observing corals that are able to recover quickly from bleaching; they may be able to use this knowledge to change environments enough to expel weak cells, and strengthen others in order for possible recovery overtime. Information like this is crucial for understanding the recovery process, possibly becoming another marine breakthrough capable of help human medicine.