Fig. 4: Depth profiles obtained from Monte Carlo modelling.

a, The ratio of the kinetic sorption rates averaged for 1,450 runs of the Monte Carlo modelling to the desorption rates also averaged for 1,450 model runs at different depths. b, The percentage contribution of the final GPS pool to the total lrDOC production (Fig. 1) at different depths. These contributions are averaged for 1,450 runs of the Monte Carlo modelling. The mathematical equations used to produce these plots are presented in Supplementary Section 3. c, The PE (%) for only POC and for both POC and MOC together, demonstrating that MOC increases calculated PE by a factor of 2.7 at 1 m depth compared with the conventional approach considering only POC. d, POC fluxes and MOC preservation rate. MOC content exceeds POC at a depth of ~50 cm and still continues to rise below this depth. All values have been averaged for 1,450 Monte Carlo model runs. The shaded areas of the curves represent 95% confidence intervals obtained from Monte Carlo model runs. The light-yellow-shaded region represents the mixed layer depth (top 10 cm).