This study investigates dissolved organic carbon (DOC) export in headwater catchments. Results show small links between DOC, nitrates, and the iron cycle throughout the year, calling into question our current conceptualization of DOC export at the catchment scale. Indeed, this study evidences that the winter period, referred as a non-productive period in our current conceptual model, acts as an active period for DOC production in riparian soils and DOC export toward stream waters.