Riding over the Kuroshio from the South to the East China Sea: Mixing and transport of DIC

Abstract

Export of dissolved inorganic carbon (DIC) to adjoining oceans enhances the potential of CO2 sequestration in marginal seas. By using a series of measured DIC depth profiles and reported flow transports, we estimated that the intermediate outflow (100–600 m) from the South China Sea is capable of transporting 6.5 ± 4.1 Tg (1 Tg = 1012g) of biologically mediated carbon (DICbio) annually to the East China Sea (ECS) via the northwardly flowing Kuroshio current. The mixing and transport of these DIC-rich waters would raise 3% and 16% of DIC/TA ratio and the Revelle factor of the adjoining seawaters, respectively. Upon upwelling onto the ECS shelf, these DIC-rich waters would counteract the potential of CO2 uptake of shelf waters that might have been enhanced by the accompanying increase in nutrient inputs, thus complicating assessment of the ECS as a net CO2 source or sink.