Original Paper

Marine Biology

, Volume 155, Issue 2, pp 173-182

First online:

Major bleaching events can lead to increased thermal tolerance in corals

  • J. A. MaynardAffiliated withGreat Barrier Reef Marine Park AuthorityAustralian Centre of Excellence for Risk Analysis, School of Botany, University of Melbourne Email author 
  • , K. R. N. AnthonyAffiliated withCentre for Marine Studies, ARC Centre of Excellence for Coral Reef Studies, The University of Queensland
  • , P. A. MarshallAffiliated withGreat Barrier Reef Marine Park Authority
  • , I. MasiriAffiliated withSchool of Geography and Environmental Studies, University of Tasmania

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access


Climate change is a major threat to coral reef ecosystems worldwide. A key determinant of the fate of reef corals in a warming climate is their capacity to tolerate increasing thermal stress. Here, an increase in thermal tolerance is demonstrated for three major coral genera (Acropora, Pocillopora and Porites) following the extensive mass bleaching event that occurred on the Great Barrier Reef (Australia) in 1998. During the subsequent and more severe thermal stress event in 2002, bleaching severity was 30–100% lower than predicted from the relationship between severity and thermal stress in 1998, despite higher solar irradiances during the 2002 thermal event. Coral genera most susceptible to thermal stress (Pocillopora and Acropora) showed the greatest increase in tolerance. Although bleaching was severe in 1998, whole-colony mortality was low at most study sites. Therefore, observed increases in thermal tolerance cannot be explained by selective mortality alone, suggesting a capacity for acclimatization or adaptation. Although the vulnerability of coral reefs remains largely dependent on the rate and extent of climate change, such increase in thermal tolerance may delay the onset of mass coral mortalities in time for the implementation of low-emission scenarios and effective management.