Fig. 3. Contour plots of advective-diffusive export flux at the base of the model euphotic zone.
a, Distribution of advective-diffusive flux by labile organic carbon (mg C m−2 day−1). b, Distribution of advective-diffusive flux by semi-labile organic carbon (mg C m−2 day−1). c, Distribution of the ratio of advective-diffusive flux to TOC flux. d, Distribution of DOC residence time in years at the bottom of the euphotic zone. The residence time is defined as the time elapsed for DOC to be upwelled to the surface ocean following its export below the euphotic zone at that grid box. The results are based on the CbPM NPP product and an e-folding remineralization time of 12 h for labile DOC.