ly characterized by the expulsion of the zooxanthellae algae, loss of algal pigmentation, or both. Coral bleaching events have had serious effects on corals and reefs worldwide. What is crucial to the understanding of zooxanthellae expulsion and bleaching is how the density of zooxanthellae within the coral is changing, if at all, under the prevailing range of environmental conditions (Gates and Edmunds, 1999). Over the last twenty years, there has been a dramatic increase in both the frequency and intensity of coral bleaching events. Sixty major bleaching events have been reported between 1960 and 1979, whereas only nine were reported prior to 1979 (Huppert and Stone, 1998). Given the dependence of the coral on this symbiotic algae, it is important to determine the cause of these bleaching events. According to Helvarg (2000, p.12): "Coral reefs are fragile structures living within a narrow range of temperature, clarity, salinity and chemistry. Even a slight increase in ocean temperature, or increased CO2 can cause stresses such as bleaching These stresses slow the rate of growth of the corrals With some 60 percent of the worlds coral reefs now losing productivity, its becoming a global crisis and a scientific mystery."Scientists have been trying to solve this "scientific mystery" by evaluating each environmental condition that may be a cause for coral reef bleaching. A number of explanations for coral bleaching have been proposed, including unusually highseawater temperatures, high doses of ultraviolet light, bacterial infection, and changes in salinity. Huppert and Stone (1998) published a report on coral reef bleaching. They tested the role of the oceans natural El Nio cycle and how "hot spots," concentrated areas of the ocean that are abnormally warmer than average conditions, may affect coral bleaching. They attempted to demonstrate how environmental conditions, in particular temperature, determine the regularity in whi...
