El Nino Impacted Coral Reefs in the Tropical Eastern Pacific: Secondary Disturbances, Recovery and Effects on Community Diversity and Reef Growth

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This project will long term study that has focused on ecological disturbances, causes, and the responses of eastern Pacific reef coral populations and reef communities during and following the severe and historically unprecedented 1982 1983 El Nino / Southrn Oscillation (ENSO) event. This study involves strong international collaboration with host country research teams working at several field sites in Costa Rica, Panama, and the Galapagos Islands (Ecuador), all areas that were severely affected during the 1982 1983 ENSO disturbance. This study will continue with (a) monitoring the physical and biological conditions of eastern Pacific coral reefs initiated in the early to mid 1970s, (b) investigating the responses of different coral species to ENSO stressors (chiefly positive sea temperature anomalies) under controlled microcosm conditions, (c) studying coral reproductive ecology as it relates to recruitment success in field surveys, and (d) documenting coral community recovery or changes leading to alternate, non reef building communities. New research directions initiated in 1994 will be pursued, namely (e) an attempt to link coral bleaching/mortality with local and global scale sea surface temperature (SST) anomalies, and (f) modeling the size structure of coral populations and coral community dynamics based on mechanistic relationships between temperature, predation, coral growth, and survivorship derived from field monitoring and experimental results. In addition, (g) analyses of the molecular genetic structure of the different zooxanthella taxa found in eastern Pacific corals to assess the importance of zooxanthellae diversity in explaining the variability in patterns of coral bleaching, and (h) recovering coral populations, to assess their genetic structure and diversity in relation to population size and distance from source populations, will be investigated.