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Billen, Gilles; Garnier, Josette; Ramarson, Antsiva; Romero, Estela; Thieu, Vincent; Le Noe, Julia; Silvestre, Marie; Thery, Sylvain; Barles, Sabine; Bognon, Sabine; Castaings, Jerome; Legendre, Romain; Riou, Philippe; Bacq, Nicolas; Fisson, Cédric. |
Le système agro-alimentaire du bassin de la Seine est aujourd’hui caractérisé par une extrême spécialisation en grandes cultures céréalières de sa partie centrale, l’élevage étant repoussé vers sa frange orientale où domine la polyculture-élevage, et celle occidentale dont les systèmes se rapprochent du modèle d’élevage intensif du Grand Ouest. Cette spécialisation s’inscrit dans le mouvement historique de «modernisation» de l’agriculture qui s’affirme au milieu du XXe siècle, et est accentué en ce début de XXIe siècle par les politiques publiques et privées qui visent à renforcer la concentration de population le long de l’axe Paris-Le Havre («Le Grand Paris») au détriment des zones amont du bassin, et à accroitre la place de la France comme exportatrice... |
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Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00416/52796/53695.pdf |
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Garnier, Josette; Riou, Philippe; Le Gendre, Romain; Ramarson, Antsiva; Billen, Gilles; Cugier, Philippe; Schapira, Mathilde; Théry, Sylvain; Thieu, Vincent; Ménesguen, Alain. |
The continental coastal waters of the Eastern Channel, from Normandy to Hauts-de-France, are subject to the major influence of unbalanced nutrient inputs from inflowing rivers. Several episodes of harmful algal blooms (HABs) compromising fishing and shellfish farming activities have been observed at the coast. For a better understanding of how the land-to-sea aquatic continuum functions, the GRAFS-RIVERSTRAHLER river biogeochemical model was implemented to cover the watersheds of 11 rivers flowing into this area (including the Seine) and chained with the ecological marine ECO-MARS3D model, applied to the French Northern coastal zone. Human activities strongly impact on the functioning of coastal ecosystems. Specifically, for these fertile soils of Northern... |
Tipo: Text |
Palavras-chave: Toxic microalgae; Pseudo-nitzschia spp.; River basins; Nutrient flows; Scenarios; Coastal zone ecosystem; Modelling. |
Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00589/70076/68049.pdf |
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Romero, Estela; Garnier, Josette; Billen, Gilles; Ramarson, Antsiva; Riou, Philippe; Le Gendre, Romain. |
The model ECO‐MARS3D, successfully applied thus far to coastal ecosystems, has been extended to encompass the Seine estuary up to Poses, at the limit between the river and the estuary. We used updated bathymetric data and thoroughly calibrated the hydrodynamics and the sedimentary dynamics in the turbidity maximum zone (TMZ). Biogeochemical processes related to oxygen were newly implemented, and freshwater phytoplankton and zooplankton groups were added to the existing marine groups. The simulations allowed us to evaluate the filter effect of the estuary with regard to the main nutrients (N, P, and Si). Today, this filter role appears quite limited and variable depending on the hydrology. On average, considering three different hydrological years, the... |
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Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00469/58067/60463.pdf |
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