Seminari del Dr. Gilles Pinay (OSUR-ECOBIO-CNRS): ‘Upscaling nitrogen removal capacity from riparian zone to the landscape scale’. 12 de febrer del 2015. Seminaris del CEAB.
‘Denitrification is the main process removing nitrate in drainage basins, which buffers input from agricultural land and limits aquatic ecosystem pollution. However, the identification of these hotspots (including riparian zones) and their role in a landscape context and the evolution of their overall removal capacity at the drainage basin scale are still challenging. The main approaches used, i.e. mass balance method, denitrification proxies and potential wetted areas, suffer from methodological drawbacks. We review these approaches and the 3 frameworks that have been proposed to date to formalize the understanding of the forces driving denitrification, i) diffusion versus advection pathways of nitrate transfer, ii) the biogeochemical hot spot, iii) the Damköhler ratio. Based on these frameworks we propose to use high resolution mapping of catchment topography and landscape architecture to define both, potential denitrification sites and the dynamic hydrologic modeling at a similar small spatial scale (< 10 km2). This would allow the characterization of the “denitrification architecture” of the drainage basins and the quantification of cumulative denitrification activity at the small catchment scale, using spatially distributed Damköhler and Peclet numbers and biogeochemical proxies.’