The role of water nitrogen retention in integrated nutrient management: assessment in a large basin by different modelling approaches

The removal of excessive nitrogen (nitrogen retention) is an important service that the aquatic ecosystem provides to humans. Assessing the removal of nitrogen (temporal and permanent) in large river basins is complex due to the dependency on climate, hydrological and physical characteristics, and ecosystem functioning. Measurements are generally limited in number and do not represent the full integration of all processes contributing to nitrogen retention in the river basin. However, the estimation of nitrogen retention by the ecosystem is crucial to understand the water pollution and the N2O emissions to the atmosphere, as well as the lag time between the implementation of agri-environmental measures to reduce nitrogen pollution and the improvement of water quality. Models have often been used to overcome the lack of information and to understand the dynamic of the river basin system. The objective of this study is to assess the nitrogen retention in a large river basin, the Seine basin (~70000 km2, in France), by the application of three models of different complexity and developed for different specific purposes: GREEN, SWAT and RiverStrahler. The study analyses the different modelling approaches and compares their estimates of water nitrogen retention over a period of 10 years. Then it reflects on the role of nitrogen retention by aquatic ecosystems in integrated nutrient management. The results of this study are relevant for the understanding of nitrogen retention process at the large river basin scale and for the analysis of scenarios of mitigation measures to reduce nitrogen impacts on aquatic ecosystems and climate.

GRIZZETTI Bruna;  PASSY Paul;  BILLEN Gilles;  BOURAOUI Faycal;  GARNIER Josette;  LASSALETTA Luis; 

2015-06-22

IOP PUBLISHING LTD

JRC91596

1748-9326,   

http://iopscience.iop.org/1748-9326/10/6/065008/,    https://publications.jrc.ec.europa.eu/repository/handle/JRC91596,   

10.1088/1748-9326/10/6/065008,