Determination of the denitrification capacity of unconsolidated rock aquifers using 15N tracer experiments at groundwater monitoring wells development of a new method to assess actual and future denitrification in aquifers The nitrogen cycle is one of the most important nutrient cycles in terrestrial ecosystems and has been dramatically altered by increasing anthropogenic inputs of reactive nitrogen (Nr) to terrestrial ecosystems. Nitrate (NO3−) emissions from the agricultural sector are the dominant source of Nr fluxes to aquatic systems like aquifers and NO3− pollution of groundwater is a problem due to eutrophication of surface waters receiving polluted groundwater possible indirect emissions of nitrous oxide (N2O) and increasing costs for keeping the standard for NO3− in drinking water. Denitrification i...