La Tour du Valat

Institut de recherche pour la conservation des zones humides méditerranéennes

Titre :	Climatic influences on riverine nitrate flux: Implications for coastal marine eutrophication and hypoxia
Auteurs :	D. Justic, Auteur ; R. E. Turner, Auteur ; N. N. Rabalais, Auteur
Type de document :	Article
Dans :	Estuaries (26(1) FEB 2003)
Article en page(s) :	1-11
Résumé :	The average nitrate flux of the lower Mississippi River increased 3.3-fold between 1954-1967 and 1983-2000. During the same time period, the average nitrate concentration increased 2.3-fold while the average discharge increased 40%. Partitioning of the observed trend in nitrate flux among the two flux components, nitrate concentration and discharge, revealed that about 80% of the observed increase in flux could be explained by the increase in nitrate concentration. This indicates that a historical increase in the anthropogenic nutrient inputs has had a far greater impact on the lower Mississippi River nitrate flux than a change in climate. The influence of climatic factors on nitrate flux has been significant and may further increase as a result of global climate change. This argument is supported by two tines of evidence. The residual component of nitrate flux, obtained by removing a trend from the time series, is controlled primarily by the variability in discharge, i.e., climatic factors. Also, there is a highly significant relationship between discharge and nitrate concentration at the low end of the discharge spectrum (

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