In 1998 the Seychelle Islands experienced severe coral bleaching as a result of the El Niño Southern Oscillation (ENSO). Historically it is the largest, most intense, and prolonged bleaching event ever observed. Coral bleaching describes the “whitening” of corals resulting from the loss of zooxanthellae, a coral building algae responsible for making corals colorful and ensuring their survival. It is directly caused by higher-than-average sea surface temperatures and ENSO, which are associated with climate change. Satellite imagery identifies and tracks Sea Surface Temperature (SST) hotspots, which was used by reef scientists to analyze the 1998 bleaching event. The Seychelle Islands contain some of the most severely impacted reefs, which were part of the most extensive reefs within the Western Indian Ocean. They provide coastal protection, tourism, recreation, and fisheries, comprising 10% of the Seychelle’s GDP. Mortalities of this scale are largely unprecedented: the 1998 bleaching caused a 95% mortality of its reefs and altogether a loss of 16% of the world’s reefs. Nowadays ENSOs are supposedly reoccurring at 10- to 15-year intervals, instead of the normal 20–30 years. This threatens locations like the Seychelles, whose people are almost exclusively reliant on their marine ecosystems. The impact on reefs also demonstrates how severely ecosystems can be impaired by climate change.
Contributed by Sophie Bernstein
Course: Global Environmental History
Instructor: Andrew Stuhl, Ph.D.
Bucknell University, Lewisburg, US
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- Lough, J. M. "1997–98: Unprecedented Thermal Stress to Coral Reefs?" Geophysical Research Letters 27, no. 23 (2000): 3901–04.
- Payet, Rolph, and Wills Agricole. "Climate Change in the Seychelles: Implications for Water and Coral Reefs." AMBIO: A Journal of the Human Environment 35, no. 4 (2006): 182–9.
- Spencer, Thomas, Kristian A. Teleki, Clare Bradshaw, and Mark D. Spalding. "Coral Bleaching in the Southern Seychelles during the 1997–1998 Indian Ocean Warm Event." Marine Pollution Bulletin 40, no. 7 (2000): 569–86.