Assessing the global flux of organic carbon transported from terrestrial surfaces to oceans by rivers

The magnitude and distribution of organic carbon (OC) transport from the terrestrial surface to the oceans is not well understood on a global scale. This hinders our understanding of terrestrial and marine carbon cycles. In this study, we determined the characteristics of OC flux. Our results showed that approximately 420 Tg C/yr of OC are transported from the terrestrial surface to the oceans, including 220 Tg C/yr of particulate organic carbon (POC) and 200 Tg C/yr of dissolved organic carbon (DOC). Asia, with only 32.46% of the basin area, accounts for 57.65% of the total POC flux, while North America, with only 17.52% of the basin area, accounts for 37.51% of DOC flux. Of these, the Pacific receives 48% of the total POC flux, and the Atlantic receives 46% of the total DOC flux. Five key zones are diagnosed and identified, in which latitudes between 5° N and 20° S contributed 72.76% of the global OC flux. Such insights directly reveal global riverine OC flux, which helps us to comprehensively understand the terrestrial and marine carbon cycles.