The indirect effects of ocean acidification on corals and coral communities

Summary

This systematic review synthesises evidence on both direct physiological effects of ocean acidification on reef-building corals and the indirect ecosystem-level consequences of altered species interactions. The authors find that acidification impacts accumulate at larger spatial scales through sub-lethal stress, and that indirect effects—particularly declines in coralline algae settlement substrate and increased bioeroders—may substantially amplify direct negative effects on coral recruitment, calcification and reef persistence. The review identifies critical knowledge gaps around herbivory dynamics, macroalgal competition and changes to coral habitat provision for associated fauna.

UK applicability

This review concerns tropical and subtropical coral reef ecosystems and has limited direct applicability to UK terrestrial or temperate marine systems. However, findings on acidification mechanisms and indirect trophic effects may inform UK policy responses to ocean acidification affecting British Overseas Territories with coral reefs and inform broader marine ecosystem resilience planning.

Key measures

Physiological stress responses to acidification; coral calcification rates; recruitment and settlement cues; abundance of crustose coralline algae and bioeroders; coral cover; ecosystem function and biodiversity

Outcomes reported

The study reviewed physiological effects of ocean acidification on reef-building corals from cellular to population scales, and synthesised evidence on indirect effects arising from altered species interactions. It identified that direct acidification effects accumulate as sub-lethal physiological stress at larger scales, whilst indirect effects through changes in coralline algae, bioeroders, herbivory and coral habitat provision may compound population and ecosystem-level declines.

Topic tags