Explain how warmer coastal waters resulting from global climate change may affect coral reefs. ...

If water temperatures increase many species of coral will eject their zooxanthellae, subsequently bleaching and dying. Also, global climate change is strongly correlated with rising carbon dioxide levels, increasing amounts of which will dissolve in ocean waters. This produces acidification of ocean waters, and increased acidity increases the conversion of limestone, which comprises the corals' skeletal material, into soluble bicarbonate, i.e. increases the mortality of corals. On the other hand, corals may be able to colonize waters that were previously too cold for them and also move into low-elevation areas that may become flooded by expanding oceans.