Print PageCoral reefs are thought to be more sensitive to climate change than any other marine ecosystem. Sea surface temperatures (SST) of only 1-2 °C can lead the phenomena known as coral bleaching, a loss of colour from the reef-building animals due to a breakdown of the symbiosis with the dinoflagellate Symbiodinium which reside in coral tissue. Occurrences of mass coral bleaching and associated coral mortality around the world over the past three decades have been attributed to rising ocean temperatures. Projected ocean warming over the next three to four decades may make mass coral bleaching a frequent occurrence on most reefs worldwide, depending on assumptions about acclimation and adaptation. Identifying regions and habitats resilient to thermal stress is critical to helping coral reef ecosystems persist in a warming world.This presentation will examine the impact of past temperature experience on the sensitivity of coral reef ecosystems to present and projected future thermal stress using physical, biological and geological data collected along a latitudinal gradient of temperature variability in the Central Equatorial Pacific nation of Kiribati since 2005.
Results/Conclusions
The coral reefs of the little-known island nation of Kiribati experience the highest inter-annual SST variability of any coral reefs in the tropics due to the El Nino / Southern Oscillation (ENSO). A variety of lines of evidence, including the absence of bleaching-sensitive species, rapid recovery of global coral cover from a 2004 bleaching event and lack of sensitivity to a subsequent warm water event at the more equatorial sites, suggest that past temperature variability affects coral resistance and recovery from bleaching. Furthermore, the expansion of “weedy” bleaching-sensitive species like Porites Rus at the sites with the highest temperature variability and highest local human disturbance paints a surprising picture of “resilience” to climate change.
phone 202-833-8773