Under normal conditions, algae live symbiotically within the coral, giving it color and providing it with a source of food. But under stress, the coral expels the algae, leaving it whitened, or “bleached.” The longer the coral remains bleached, the more likely it is to die, according to marine biologists.
Following a hot summer – the fourth hottest on record for the US, according to the National Oceanic and Atmospheric Administration (NOAA) – nearly the entire Caribbean was at risk for bleaching. While some bleaching occurs every year, this year stands out.
“Temperatures are high in the Caribbean, and we expect this to continue. This season has the potential to be one of the worst bleaching seasons for some reefs,” Mark Eakin, coordinator of NOAA’s Coral Reef Watch, said in a statement in late September.
The phenomenon is not confined to the Caribbean. Coral reefs in Southeast Asia and in the Indian Ocean are experiencing their worst bleaching since 1998. Scientists expect similar results for the Great Barrier Reef off the coast of Australia.
The environmental and economic impacts are potentially enormous.