Multi-isotope and chemical tracing for understanding the sources and fate of macronutiments at the basin scale (MUTUAL)
Nitrogen and phosphorous flows induce water quality degradations which are a major obstacle for reaching the “good qualitative status” of European surface and groundwater bodies aimed by the European Water Framework Directive (WFD). A diverse array of macronutrient sources and a complex network of transport pathways and reactive transformations are evident for both groundwater and surface water receptors. This diversity of sources and pathways is a key challenge for the management of natural resources. Understanding macronutrient sources and fate across large scales requires a multi-method and multi tracer approach. This STUDIUM consortium gathers both a critical mass of experience on nutrient cycling in a variety of hydroclimatic, hydrogeological and land use settings and a large variety of complementary tools in the field of environmental geochemistry. Reinforced networking among the partners will allow merging advanced tracer techniques into a diagnostic toolbox for characterising macronutrient (N and P) sources and fate in aquatic ecosystems for improved process understanding and catchment management. The regular interactions between the partners will allow for a better understanding of nitrogen and phosphorous contamination of water resources, of their speciation and transformations and of residence and transfer times of in in the different subsoil compartments.
Main outputs will be a shared data base on chemical and isotopic fingerprints of N and P sources in a diversity of catchments worldwide as basis of a common publication, and a critical analysis of the current approaches of source- and fate identification in contaminated watersheds. A dedicated conference session at European Geosciences Union meeting EGU2018 and an international workshop organised in Orléans (Centre Region, France) will bring together international experts in the field of nutrient cycling and -tracing with a variety of regional and national stakeholders.