An Examination of the “Continental shelf pump” in an open ocean general circulation model


  • Andrew Yool,

  • Michael J. R. Fasham


In a recent study of the shelf region of the East China Sea, Tsunogai et al. [1999] estimated that a combination of air-sea exchange and biological and physical transport processes could transfer carbon from the shelf region into the open ocean at a rate of 35 g C m−2 yr−1. Contrasting with the solubility and biological pumps of the open ocean, they described this collective activity as the “continental shelf pump” and suggested that if this pump operated throughout the world's shelf regions, it could be responsible for ocean uptake of ∼1 Gt C yr−1 (≈50% current ocean uptake of anthropogenic CO2). In this work a general circulation model (GCM) is used to explore the potential strength of this pump across the world's shelves. Since the GCM does not represent the continental shelf regions explicitly, a parameterization of the pump has been used. Results of simulations find modeled pump activity very variable between shelf regions, with the East China Sea shelf behaving very similarly to the global average. Storage of pump carbon is particularly high in the Atlantic Ocean and other regions where deep water is formed. A considerable reservoir of pump carbon becomes trapped under the Arctic ice sheet. Simple extrapolations from the results suggest that should shelf regions absorb CO2 at the rate of the East China Sea, the pump would account for a net oceanic uptake of 0.6 Gt C yr−1.