Coral responses to anthropogenic stress in the twenty-first century: an ecophysiological perspective

The number of ecophysiological studies involving reef corals has increased markedly over the last 20 years, driven primarily by the concern over the potential effects of anthropogenic change on coral communities. In particular, the evaluation of the effects of global climate change has prompted major research efforts into understanding the consequences of both rising seawater temperatures and ocean acidification on the physiology of corals. In recent years the recognition that corals harbour not only symbiotic algae but also a diverse microbial consortium, which may both influence and be influenced by the physiology of the animal host, has added an extra layer of complexity to this biological system known collectively as the 'coral holobiont'. The present review draws together an extensive literature on ecophysiological responses of the coral holobiont to anthropogenic change, with specific references to the latest molecular and genetic developments in the field. It also highlights gaps in our basic understanding of coral physiology and draws attention to the value of extreme physical habitats in elucidating the acclimatory and adaptive scope of reef corals to climate change.