Abstract:Coral reefs are one of the most productive, and yet most vulnerable marine ecosystems. The global decline of coral reefs induced by climate change and human activities has already affected the processes of coral calcification and carbon cycling in the reef ecosystem, intensifying the long-standing CO₂ “source-sink” debate over coral reefs. Despite the fact that coral calcification is accompanied by the release of CO₂ to the atmosphere, the significance of coral reefs as a carbon sink cannot be ignored, given the complex biogeochemical processes in the reef ecosystem and the characteristic mixotrophic lifestyle of the reef-building corals. From the perspective of increasing coral resilience to climate change, this study attempts to clarify the controversy over the coral reef CO₂ “source-sink” debate, explore the possible ecological regulations and pathways to transform coral reefs from a carbon source to a carbon sink, and provide theoretical framework and technical support for the deployment of ocean negative carbon emissions and the implementation of the national carbon neutrality strategy.