Fig. 3: The relative importance of different processes.

a,b, The relative importance (%) of six processes to PE when MOC is considered in addition to POC (a) and to preservation rates for MOC (b). The six processes are DOC hydrolysis, DOC remineralization, mixing, equilibrium adsorption, kinetic sorption and geopolymerization. The newly defined PE is given by equation (7). The preservation rates for MOC are shown as the rate of MOC formation, which is the sum of net kinetic sorption rates integrated at the depth of 1 m (µmol cm⁻² yr⁻¹) for DOC, GPS and lrDOC. The importance of each process is obtained on the basis of the maximum sensitivity of the parameters categorized for each process. The categorization is presented in Supplementary Table 9. Each bar is the mean of 1,000 executions of the process importance analysis, and the error bars represent the 95% confidence interval. Details of sampling in the Monte Carlo method for process importance analysis are provided in Supplementary Sections 1.3–1.5 and in previous studies³⁵.