Consulta: subjectFacets:"Marée verte"
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Data/hora: 01/06/2024 08:01:35

L'utilisation de modèles écologiques dans la lutte contre l'eutrophisation des eaux côtières françaises
Provedor de dados: 5
Autores: Menesguen, Alain.
Increasing anthropogenic nitrogen and phosphorus loadings in some coastal areas have induced during the last twenty years excessive production of algal material, either phytoplanktonic or macrophytic. This so-called eutrophication phenomenon alters the usual structure of ecosystem and can lead to massive kills caused by anoxia in some extreme cases, when almost all the dissolved oxygen in bottom waters has been consumed by organic matter decomposition. Just behind the semi-enclosed lagoons, the most sensible areas are the dilution plumes of main rivers. In the case of French coasts, mediterranean lagoons have been eutrophicated for a long time, whereas the coastal areas of the Bay of Biscay and English Channel have been partially preserved by the strong...
Tipo: Text
Palavras-chave: Ecological models; Hydrodynamical models; Residence time; Limiting factor; Phytoplankton blooms; Green tides; Coastal eutrophication; Modèles écologiques; Modèles hydrodynamiques; Temps de résidence; Elément limitant; Eau colorée; Marée verte; Eutrophisation côtière.
Ano: 1999
URL: http://archimer.ifremer.fr/doc/1999/rapport-144.pdf

Simulation de l'effet sur l’eutrophisation côtière bretonne de 3 scénarios de réduction des teneurs en nitrate et phosphate de chaque bassin versant breton et de la Loire
Provedor de dados: 5
Autores: Dussauze, Morgan; Menesguen, Alain.
This study commissioned by the Région Bretagne and the Agence de l'Eau Loire Bretagne aimed at assessing on a mathematical modelling basis the marine influence of most of watersheds in Brittany, and the impact of 4 scenarios of reduction of the loadings of each of these watersheds on the phytoplanctonic biomass and ulva mass proliferation. The ecological 3D model ECOMARS3D has been applied to a domain containing Brittany (which is also used in an operational mode for putting everyday the 2dayforecasts on the website: http://www.previmer.org/previsions/production_primaire/modele_eco_mars3d_bretagne) and to 6 zooms which enabled a finer representation of coastal waters. This study highlighted the fact that: •a nitrate reduction for any river has no effect on...
Tipo: Text
Palavras-chave: Bretagne; Bassins versants; Eaux côtières; Nitrate; Phosphate; Marée verte; Ulve; Diatomée; Dinoflagellé; Modèle mathématique; Brittany; Watersheds; Coastal waters; Nitrate; Phosphate; Green tide; Ulva; Diatom; Dinoflagellate; Mathematical model.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/00097/20804/18429.pdf

Simulation de l'effet de 3 scénarios de réduction des teneurs de l'Elorn en nitrate sur l'eutrophisation de la rade de Brest
Provedor de dados: 5
Autores: Menesguen, Alain.
This study commissioned by the Syndicat de l'Elorn et de la Rivière de Daoulas aimed at assessing on a mathemical modelling basis the impact of 3 scenarios of reduction of the loadings of Elorn river (imposed concentrations : 20, 15 et 10 mg/L NO3) on the status of ulva mass proliferation in the Moulin Blanc cowe (Bay of Brest). An ecological 3D model of N, P and Si cycling in the bay of Brest has been applied to a "reference situation": 2004 meteorological forcing combined to recent loadings of the new sewage plant. This model showed that: · the 3 reduction scenarios did not reduce significantly the early summer biomass of ulvae, but allowed to slightly reduce the subsequent summer and autumn levels of biomass (up to 20% reduction for 10 mg/L NO3). The...
Tipo: Text
Palavras-chave: Mathematical model; Dinoflagellate; Diatom; Ulva; Green tide; Nitrate; Moulin Blanc cowe; Elorn river; Bay of Brest; Modèle mathématique; Dinoflagellé; Diatomée; Ulve; Marée verte; Nitrate; Anse du Moulin Blanc; Elorn; Rade de Brest.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/rapport-6327.pdf

Les "marées vertes" en Bretagne, la responsabilité du nitrate
Provedor de dados: 5
Autores: Menesguen, Alain.
Since 25 years, an increasing number of beaches and coves along the Britanny coast are invaded from spring until autumn by proliferating green macroalgae (free ulvae, fixed enteromorphae). This typical case of eutrophication, which has been well studied in the bays of Saint-Brieuc, Lannion, Douarnenez and Brest, could be explained by the conjunction of a natural containment of shallow water masses with a recent enrichment of them by nitrate river loadings. In the naturally confined sites, field measurements of summer biomass showed a good correlation with the spring nitrate river loadings ; furthermore, the summer rarefaction of these loadings explains the fall of the nitrogen content of the ulvae, which induces the summer stop of the algal growth.  The...
Tipo: Text
Palavras-chave: Intensive farming; Biogeochemical models; Coastal eutrophication; Nitrate; Ulva; Green tide; Agriculture intensive; Modèles biogéochimiques; Eutrophisation côtière; Nitrate; Ulve; Marée verte.
Ano: 2003
URL: http://archimer.ifremer.fr/doc/2003/rapport-143.pdf