Abstract
The lateral transport of dissolved organic carbon (DOC) from terrestrial uplands to aquatic ecosystems, particularly headwater streams, plays a critical role in linking terrestrial and aquatic carbon cycles, but its spatial distribution and magnitude at the global scale remain highly uncertain. Here, we compiled 20,403 field-based DOC concentration measurements and modeled them against catchment properties to generate monthly predictions across over 90,000 forested catchments (30°S-70°N). These models explain between 64% and 90% of the total variability in DOC concentrations (R(2) values from predictions versus withheld observations), revealing previously unrecognized hotspots of terrestrial-aquatic carbon transfer. By coupling these predictions with a physically-based hydrological routing scheme (HydroBASINS database), we provide the first catchment-resolved estimates of DOC yields. This dataset represents a valuable resource for the carbon-cycle community, supporting the validation of terrestrial biosphere models and cross-checking of datasets.