- Conference Proceedings Paper
Abstract: Large amounts of terrestrial carbon and nutrients are routed to the ocean through the Land-Ocean Aquatic Continuum (LOAC). Once in coastal waters, these terrestrial inputs impact ocean carbon chemistry. Lateral carbon export from rivers has been estimated to be responsible for global-ocean outgassing of roughly 0.45 Pg C yr-1. However, the biogeochemical pathway for this outgassing has not yet been quantified. In this study, we have carried out a set of model sensitivity experiments, in which we introduce terrestrial carbon and nutrients in the ECCO-Darwin global-ocean biogeochemistry state estimate. We compute daily riverine export by combining the GlobalNEWS2.0 watershed model with point-source freshwater discharge from the JRA55-do atmospheric reanalysis. We quantify the litter and soil carbon pool for mangrove forests worldwide and the tidally-driven flux from this intertidal carbon pool to the open ocean following the time-volume change of water estimated from the combination of the FES2014 barotropic tidal model and the Global LiDAR Lowland Digital Terrain Model. We evaluate the impact of terrestrial exports on the global ocean by comparing a suite of experiments against a baseline simulation that does not include terrestrial carbon and nutrient export for the 1995–2017 period. Our study explores the role of terrestrial carbon and nutrients in the ocean’s biological and carbon chemistry. By including processes that occur at the land-ocean interface, we aim for an improved understanding of how the LOAC impacts global carbon cycling.