The goal of the project is to advance the mechanistic understanding of the response of the ocean carbon sink to changes in ocean ventilation under increasing atmospheric CO2 concentrations. This objective will be accomplished by: (1) Developing an expanded and improved theoretical understanding of ocean carbon pumps. This will be achieved by including the effects of the carbonate, solubility pumps and anthropogenic emissions in the investigator’s previous simplified theoretical framework (Marinov et al. 2008b). The theory will be used to predict the potential impact of changes in ventilation on ocean carbon pumps and the resulting feedbacks on atmospheric pCO2. (2) Designing and executing a set of coupled ocean-atmosphere model experiments suitable for evaluating the separate impacts of wind-driven and buoyancy-driven ventilation changes on the biological pump, solubility pump, and anthropogenic carbon uptake. (3) Introducing a new set of ocean physical and biogeochemical tracers and diagnostics to allow an unprecedented clean separation of ocean carbon pumps. These tools will be used to evaluate the effect of ventilation changes on both the natural biological and solubility carbon pumps and on the anthropogenic carbon uptake, the sum of which constitute the total carbon sink.