Coral reefs are made from a species of hard coral from the order Scleractinia. The polyps of this order form a hard exoskeleton made from aragonite, which is a solid form of calcium carbonate. (Matz). Climate change affects the structure of the coral reef and the hard corals themselves. Since the structure itself is pure calcium carbonate, it is naturally white. The colors attributed to coral reefs come from a symbiotic relationship that coral has with an algae, called zooxanthellae. The coral provides nutrients and shelter to the algae, and in return, the algae provides the coral with carbohydrates through photosynthesis, which is food for the coral. Bleaching occurs when coral expels the algae from its skin tissue because of a stress-related
