Sporadic disturbances in fluctuating coral reef environments: El Nino and coral reef development in the eastern Pacific

P. W. Glynn, M. W. Colgan

Research output: Contribution to journalArticle

57 Scopus citations


The intense 1982-83 El Nino-Southern Oscillation (ENSO) sea surface warming event caused extensive reef coral bleaching (loss of symbiotic zooxanthellae), resulting in up to 70-95% coral mortality on reefs in Costa Rica, Panama, Colombia and Ecuador. In the Galapagos Islands, most coral reefs experienced >95% coral mortality. Also, several coral species experienced extreme reductions in population size, and local and regional extinctions. The El Nino event spawned secondary disturbances, such as increased predation and bioerosion, that continue to impact reef-building corals. The death of Pocillopora colonies with their crustacean guards eliminated coral barriers now allowing the corallivore Acanthaster planci access to formerly protected coral prey. Sea urchins and other organisms eroded disturbed corals at rates that exceed carbonate production, potentially resulting in the elimination of existing reef buildups. In other reef-building regions following extensive, catastrophic coral mortality, rapid recovery often occurs through the growth of surviving corals, recruitment of new corals from nearby source populations, and survival of consolidated reef surfaces. In the E Pacific, however, the return of upwelling conditions and the survival of coral predators and bioeroders hamper coral reef recovery by reducing recruitment success and eroding coral reef substrates. Thus, coral reef growth that occurs between disturbance events is not conserved. Repeated El Nino disturbances prevent coral communities from increasing in diversity and limit the development and persistence of significant reef features. -from Authors

Original languageEnglish
Pages (from-to)707-718
Number of pages12
JournalAmerican Zoologist
Issue number6
StatePublished - Dec 1 1992


ASJC Scopus subject areas

  • Earth and Planetary Sciences(all)
  • Environmental Science(all)

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