Abstract: Coral reefs, often termed the "tropical rainforests of the ocean," play a critical role in global carbon cycles and climate change mitigation through organic and inorganic carbon sequestration. The South China Sea coral reefs contribute up to 11% of global carbon sequestration, holding significant ecological and economic value. This review examines the latest advancements in carbon sequestration assessment methods, focusing on the principles, applications, and strengths and weaknesses of ReefBudget Indo-Pacific, geochemical approaches, remote sensing, three-dimensional modeling, and ecosystem modeling. ReefBudget quantifies carbonate budgets through standardized surveys, geochemical methods precisely measure calcification rates, remote sensing and 3D modeling expand spatial and structural analyses, and ecosystem models predict impacts of acidification and bleaching. Research in the South China Sea is constrained by limited regional data. Future efforts should integrate multiple methods, enable real-time monitoring, establish a South China Sea carbon sequestration database, and optimize heat-tolerant coral transplantation and restoration projects to enhance carbon sequestration capacity. This paper proposes a comprehensive assessment framework centered on multi-method integration, providing scientific support for South China Sea coral reef conservation, inclusion in blue carbon inventories, and global carbon emission reduction.

Key words: coral reef, ecosystem, carbon sequestration, carbonate pumps, biological pumps, microbial carbon pumps