This project follows the overall design and objectives of “South China Sea Deep” (SCSD) Research Program, integrate the outcomes from the five on-going relevant SCSD projects towards a better understanding of the key processes and mechanisms of carbon sequestration in the ocean. The research focus on the interactions between the biological carbon pump (BP) and microbial carbon pump (MCP) and its effects on carbon sequestration under different environmental conditions. The integration is featured by coupling the epipelagic and deep waters, the water column and sediments, the micro- and macro-scale biogeochemical processes. Research contents include primary production and microbial respiration, physical and chemical variables, biomarkers for sedimentation and decomposition, along environmental gradients and temporal-spatial dimensions. This research will establish conceptual models (focusing on the process and mechanism), box-type model (focusing mainly carbon reservoirs and their interface fluxes) and ecosystem dynamics model / numerical model (with emphasis on physical - biological coupling for potential manipulation and prediction).