A near-global dataset of dissolved organic carbon concentrations and yields in forested headwater streams

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.