Ocean Carbon Pumps: Analysis of Relative Strengths and Efficiencies in Ocean-Driven Atmospheric CO 2 Changes

An ocean carbon pump is defined as a process that depletes the ocean surface of σCO2 relative to the deep-water σCO2. Three pumps are recognized: a carbonate pump, a soft-tissue pump, and a solubility pump. The first two result from the biological flux of organic and CaCO3 detritus from the ocean's surface. The third results from the increased CO2 solubility in downwelling cold water and is demonstrated by a one-dimensional upwelling-diffusion model of an abiotic ocean. In the soft-tissue and solubility pumps, working strengths are defined in terms of the ΔσCO2 each creates between surface and deep-water. Efficiencies of each pump are quantified as a ratio of working strength to potential maximum strength.…