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Introduction | Identification | Impacts | Causes | Actions | More Info
|In 1998, a wave of mass coral bleaching affected reefs around the globe. This dramatic and damaging phenomena caught the attention of scientists and citizens around the world and has resulted in greater awareness and concern about the possible impacts of climate change on coral reef ecosystems. Coral bleaching occurs when corals are stressed by environmental conditions such as unusually high sea temperatures, low salinity, and exposure to toxic chemicals. It is characterized by the loss of microscopic algae called zooxanthellae that live within the tissues of most corals. Zooxanthellae not only provide corals with a food supply, they are also responsible for giving corals their distinctive green and brown coloration. High water temperature is the most common stress that leads to coral bleaching and is the trigger for the large-scale bleaching events seen in 1998. Though some corals can recover from bleaching by regaining their zooxanthellae, others may die (CRC Reef). Reefs are at risk of mass coral bleaching events during the months that normally experience the highest sea temperatures.||
|School of Zanclus cornutus among bleached Acropora thickets.
Location: Hikkaduwa, Sri Lanka
Photo by: A. Rajasuriya
(from ReefBase: http://www.reefbase.org)|