Coral Bleaching |
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Warmer water temperatures brought on by climate change stress corals because they are very sensitive to changes in temperature. If water temperatures stay higher than usual for many weeks, the zooxanthellae they depend on for some of their food leave their tissue. Without zooxanthellae, corals turn white because zooxanthellae give corals their color. White, unhealthy corals are called bleached. Bleached corals are weak and less able to combat disease.
Bleaching events on coral reefs around the globe were observed in 1998. In some Pacific islands, a little bit of bleaching is common in the summer; however, there have been times when bleaching is particularly bad in this region. For example, larger than normal bleaching events in the National Park of American Samoa occurred in 1994, 2002, and 2003. As climate change continues, bleaching will become more common, and the overall health of coral reefs will decline. |