Coral Reef Biodiversity and Thermal Bleaching Responses under Climate Change

Abstract

Coral reefs occupy less than one percent of the ocean floor but host approximately a quarter of described marine species. Climate-driven sea-surface warming has produced five global mass-bleaching events since 1998, with the 2014–2017 event inflicting unprecedented coral mortality on the Great Barrier Reef and other systems.^1,2 This paper reviews the biology of reef-building corals and their obligate endosymbionts, the thermal physiology of bleaching, the documented global bleaching record, and the prospects for adaptation, assisted evolution, and ecosystem-based conservation. Quantitative region-wise coral-cover declines are summarised. The paper concludes that meaningful long-term reef persistence requires atmospheric-CO₂ stabilisation well below 2°C warming, supplemented by locally targeted reduction of compounding stressors and selective reef-restoration programmes.