Nitrogen Removal in Valley Bottom Wetlands: Assessment in Headwater Catchments Distributed throughout a Large Basin.

The article offers information about a study that quantifies the impact of valley bottom wetlands on NO₃^- concentrations in streams in the Brittany region of France. The proponents analyzed the spatial variation in NO₃-N concentrations in 18 headwater catchments located in a 400 square kilometer basin, with varying topographic, climatic, and agricultural intensity conditions. Results of the study demonstrate the contribution of natural valley bottom wetlands to NO₃^- removal at the catchment scale compared to other sources of variation, which is a need for integrating water quality criteria into wetland management.