Inventory of released inorganic carbon from organic matter remineralization in the deeper Arabian Sea

An attempt is made to quantify the biological carbon pump in Arabian Sea subsurface waters by estimating the total concentrations of remineralized dissolved inorganic carbon (DICrem) and its water column inventory. The influence of different sets of -DeltaO(2)/DeltaC(org) ratios, which are either constant or variable with depth, on the estimate is assessed. Throughout the water column the horizontally mapped DICrem concentrations increase northward due to enlarged export fluxes of organic matter and subsequently enhanced remineralization processes as well as to the accumulation of remineralization products along the trajectory path of the water masses ventilating the Arabian Sea from the southern Indian Ocean. The choice of the remineralization ratios generates significant differences in the DICrem concentrations at specific depth horizons. The DICrem inventory of the Arabian Sea between 500 and 4500 m in the years 1995-1997 amounts to similar to39-44 Gt C depending on the applied remineralization ratios