Avoiding eutrophication of Europe's valuable coastal areas
Nitrate finds its way into our groundwater from a number of sources, including fertilizer application in agriculture as well as livestock and human waste management. Apart from contamination of drinking water supplies, coastal waters are also at risk. When nitrate-rich groundwater mixes with relatively nutrient-poor seawater at the coastal boundary, the result is eutrophication. The ensuing plant growth and algal blooms negatively impact biodiversity and can even produce a toxic environment in these delicate ecosystems. Prior to the NAME project sponsored by the Energy, Environment and Sustainable Development Programme, the magnitude of the nitrate flux from groundwater into the sea was unknown. Thanks to important research performed by the Technical University of Denmark, important insight into nitrogen cycling at this crucial boundary has been obtained. Measurements of the amount of nitrate released into the sea from a groundwater aquifer were made. Models were then applied to track the fate of this nitrate in the nitrogen cycle, addressing the complex biogeochemical conversion processes that occur. The Danish scientists established that the groundwater nitrate flux is considerable and should be taken into account. It was determined, however, that under certain conditions the nitrate is converted into harmless free nitrogen. This knowledge will be useful for coastal managers looking to avoid the unwanted effects of eutrophication, which can decrease the value of these important natural resources.
