HotPaNTS · Hot-spots of Phosphorus and Nitrogen delivery in Time and Space in agricultural catchments

Hot-spots of Phosphorus and Nitrogen delivery in Time and Space in agricultural catchments

Human activities, mainly diffuse pollution from agriculture, have led to a gradual deterioration of water quality in streams, rivers and seas and their eutrophication. Combating eutrophication is proving difficult and expensive and emphasizes gaps in our current understanding of sources and fate of agricultural pollution. One potential reason for this is poor targeting of diffuse agricultural pollution both in space and time by existing monitoring networks. To address this scientific challenge, we tested a hypothesis that organic matter measurements obtained with low-cost and portable optical sensors could provide vital information on hot-spots of diffuse pollution in space and time. To test this hypothesis, the project evaluated spatial and temporal relationships between phosphorus and nitrogen, two main nutrients responsible for eutrophication, and organic matter measurements in agricultural streams. These relationships were tested over two years for 10 agricultural catchments and 9 observation fields in Sweden, covering a gradient in climatic, hydrological, biogeochemical and land use conditions. Preliminary results show that: (1) relationships between nutrients and organic matter are site-specific and dependent on dominant geology, soil properties and dominant flow pathways in the catchment and (2) turbidity and organic matter fluorescence measurements obtained with optical sensors can characterise sources and dynamics of diffuse pollution. These findings show that we can use optical sensor technology to improve targeting of eutrophication pressures both in space and time. In the long-term, this can help us to mitigate eutrophication by better control of sources and their delivery pathways.

Data: CORDIS, © European Union