Coral reef bleaching: Facts, hypotheses and implications

Peter W. Glynn

Research output: Contribution to journalArticle

465 Scopus citations

Abstract

Coral reef bleaching, the temporary or permanent loss of photosynthetic microalgae (zooxanthellae) and/or their pigments by a variety of reef taxa, is a stress response usually associated with anthropogenic and natural disturbances. Degrees of bleaching, within and among coral colonies and across reef communities, are highly variable and difficult to quantify, thus complicating comparisons of different bleaching events. Small-scale bleaching events can often be correlated with specific disturbances (e.g. extreme low/high temperatures, low/high solar irradiance, subaerial exposure, sedimentation, freshwater dilution, contaminants, and diseases), whereas large scale (mass) bleaching occurs over 100s to 1000s of km2, which is more difficult to explain. Debilitating effects of bleaching include reduced/no skeletal growth and reproductive activity, and a lowered capacity to shed sediments, resist invasion of competing species and diseases. Severe and prolonged bleaching can cause partial to total colony death, resulting in diminished reef growth, the transformation of reef-building communities to alternate, non-reef building community types, bioerosion and ultimately the disappearance of reef structures. Present evidence suggests that the leading factors responsible for large-scale coral reef bleaching are elevated sea temperatures and high solar irradiance (especially ultraviolet wavelenths), which may frequently act jointly.

Original languageEnglish
Pages (from-to)495-509
Number of pages15
JournalGlobal Change Biology
Volume2
Issue number6
StatePublished - Dec 1 1996

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Keywords

  • Bleaching
  • Coral reefs
  • Global change
  • Stress
  • Zooxanthellae

ASJC Scopus subject areas

  • Environmental Science(all)
  • Ecology
  • Environmental Chemistry
  • Global and Planetary Change

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