Global Warming Leads to Coral bleaching

Warmer sea surface temperatures are blamed for an increase in a phenomenon called coral bleaching. It is a whitening of coral caused when the coral expels a single-celled, symbiotic alga called zooxanthellae. This alga usually lives within the tissues of the corals and, among other things, gives them its spectacular range of colours.

Zooxanthellae are expelled when the coral is under stress from environmental factors such as abnormally high water temperatures or pollution. Since the zooxanthellae help coral in nutrient production, their loss can affect coral growth and make coral more vulnerable to disease. Major bleaching events took place on the Great Barrier Reef in 1998 and 2002, causing a significant die-off of corals in some locations.