ea (Bryant, 1998).Medicine - About half of the potential pharmaceuticals being explored are from the oceans, many from coral reef ecosystems. Several promising drugs have already been identified, developed, and tested (Carte, 1996).Ecological Indicators - Due to the potential vulnerability of modern corals to high temperature, coral reefs may be among the first systems to show signs of ecological stress from global warming (IPCC, 1998). Detecting this change will require an extensive network of monitoring sites throughout the coral reef regions of the world.Threats to Coral ReefsNatural CausesCoral bleaching is the whitening of coral colonies due to the loss of symbiotic zooxanthellae from the tissues of polyps. This loss exposes the white calcium carbonate skeletons of the coral colony. Without zooxanthellae, the coral polyps have less energy available for growth or reproduction. Scientists arent sure why bleaching occurs. Hypotheses include James W. Hyde BIOL 1040elevated water temperatures, ultraviolet radiation, and diseases or viruses affecting the zooxanthellae (Brown and Ogden, 1993). Bleaching is a natural phenomenon and is not lethal unless it occurs for long periods of time.Changes in sea level are detrimental to established corals and reefs. If there is a drop in sea level the corals are exposed, corals need water. If a rise occurs it decreases the amount of available sunlight and may inhibit growth. Added emissions of carbon dioxide and other trace gases (greenhouse gases) into our atmosphere may be causing a gradual warming of our planet. This warming could cause the polar ice caps to melt, thereby raising sea level. Rises in sea level can also release nutrients trapped in soil (...
