Where land and water meet: The role of riparian zones in catchment nutrient cycling

Nutrient supply, processing, and transport in fluvial ecosystems have received increasing attention over recent decades due to their ecological significance and influence on water quality. Within catchments, riparian zones are widely recognized as critical control points for nutrient exports, serving as the last buffer zone of terrestrial nutrient exports. However, understanding their influence on downstream nutrient patterns, compared with other nutrient sources, remains poorly constrained. In this talk, we examine some of the key mechanisms by which riparian zones influence stream nutrient dynamics across different spatial and temporal scales. By combining synoptic surveys across multiple catchment compartments (soils, groundwater, stream) with modelling approaches, we demonstrate the dual role of riparian zones as both major regulators for terrestrial nutrient inputs and controls of stream metabolism and associated nutrient processing. Further, we discuss the hydrological and biogeochemical significance of riparian zones, with particular emphasis on its variability across seasons, along the river continuum and among biomes. Overall, this talk aims to highlight the need for an integrated, landscape-scale perspective to advance our understanding of catchment biogeochemistry.