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| Registros recuperados: 63 | |
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| Loizeau, Veronique; Menesguen, Alain. |
| A five-compartment steady-state food web model is proposed for the benthic food web leading to the dab. Three exposure pathways are considered in the description of accumulation by benthic animals: ingestion of particulate contaminants associated with either sediment or phytoplankton, and respiratory uptake of free dissolved contaminant in overlaying water. Application of the model to a simple food web in the Bay of Seine (Eastern Channel) indicates that : a) feeding is the principal route of contamination, especially for PCB which have more than four chlorine atoms in the molecule ; b) excretion and growth rates, phytoplankton lipid fraction and organic carbon content of sediment are the parameters which mostly determine the chemical bioaccumulation in... |
| Tipo: Text |
Palavras-chave: MODEL; PCB; FOOD WEB; BENTHIC INVERTEBRATES; DAB. |
| Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/00100/21127/18747.pdf |
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| Guillaud, Jean-francois; Andrieux-loyer, Francoise; Menesguen, Alain. |
| As part of the French National Programme for Coastal Oceanography, this paper focuses on improvement of biogeochemical modelling in the: Bay of Seine (Eastern Channel), by introducing phosphorus in nutrient cycles. The Bay of Seine receives the Seine river, which exhibits very high nutrient concentrations, and this coastal zone constitutes a typical case of eutrophication in a river plume area. In terms of analyses, sequential extraction and analysis of sedimentary phosphorus were used in order, to measure various forms of particulate phosphorus in suspended matter and sediment (calcium-bound phosphate, Fe/Al-bound phosphate, exchangeable phosphate and organic phosphorus). In the modelling approach, the Bay is divided into 42 boxes and a two-layer,... |
| Tipo: Text |
Palavras-chave: Bay of Seine; Phytoplankton; Phosphorus; River plume; Biological two layer box model. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/2000/publication-462.pdf |
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| Lazure, Pascal; Huret, Martin; Gohin, Francis; Menesguen, Alain; Lecornu, Fabrice; Le Traon, Pierre-yves; Thomin, Pascale; Jegou, P.; Baraer, F.; Corre, Gilles; Louazel, Stephanie; Equipe projet PREVIMER. |
| Sommaire * Météo et débits des fleuves.....2 * Caractéristiques des masses d’eau côtières..............5 * Production biologique............11 * Rappel des objectifs du bulletin PREVIMER..................13 * Les moyens d’observations et de prévisions de l’état des mers côtières...........................13 * Glossaire..................................15 |
| Tipo: Text |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00242/35367/33866.pdf |
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| Menesguen, Alain; Dussauze, Morgan; Dumas, Franck; Thouvenin, Benedicte; Garnier, Valerie; Lecornu, Fabrice; Repecaud, Michel. |
| European directives (Water Framework Directive - WFD and Marine Strategy Framework Directive - MSFD) require a regular survey of several descriptors of the Environmental Status of coastal waters of the North-east Atlantic Ocean. Especially for the MSFD, which may concern large continental shelf areas where measurements are scarce, realistic ecological models can help assessing the Environmental Status. The ECO-MARS3D model of the pelagic ecosystem of the Bay of Biscay and English Channel continental shelf (NE Atlantic) has been developed for these applied purposes and validated against various types of historic data. This first paper deals with the basic biogeochemical version, which contains inorganic nutrients (NH4, NO3, PO4, Si(OH)4), three... |
| Tipo: Text |
Palavras-chave: Ecological 3D model; Continental shelf; Bay of Biscay and English Channel; Surface chlorophyll; Dissolved oxygen; MSFD. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00469/58098/60510.pdf |
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| Desmit, Xavier; Lacroix, Geneviève; Thieu, Vincent; Menesguen, Alain; Dulière, Valerie; Campuzano, Francisco; Billen, Gilles; Neves, Ramiro; Lancelot, Christiane; Gypens, Nathalie; Dussauze, Morgan; Garnier, Josette; Silvestre, Marie; Passy, Paul; Lassaletta, Luis; Guittard, Gabriel; Théry, Sylvain; Thouvenin, Benedicte; Garcia, Carla; Pinto, Ligia; Sobrinho, Joao; Mateus, Marco; Ascione Kenov, Isabella. |
| One of the leading challenges in marine science and governance is to improve scientific guidance of management measures to mitigate eutrophication nuisances in the EU seas. Too few approaches integrate the eutrophication process in space (continuum river-ocean) and in time (past, present and future status). A strong need remains for (i) knowledge/identification of all the processes that control eutrophication and its consequences, (ii) consistent and harmonized reference levels assigned to each eutrophication-related indicator, (iii) identification of the main rivers directly or indirectly responsible for eutrophication nuisances in specific areas, (iv) an integrated transboundary approach and (v) realistic short term and long term nutrient reduction... |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00292/40301/38750.pdf |
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| Le Moal, Morgane; Gascuel-odoux, Chantal; Menesguen, Alain; Souchon, Yves; Etrillard, Claire; Levain, Alix; Moatar, Florentina; Pannard, Alexandrine; Souchu, Philippe; Lefebvre, Alain; Pinay, Gilles. |
| Eutrophication is one of the most common causes of water quality impairment of inland and marine waters. Its best-known manifestations are toxic cyanobacteria blooms in lakes and waterways and proliferations of green macro algae in coastal areas. The term eutrophication is used by both the scientific community and public policy-makers, and therefore has a myriad of definitions. The introduction by the public authorities of regulations to limit eutrophication is a source of tension and debate on the activities identified as contributing or having contributed decisively to these phenomena. Debates on the identification of the driving factors and risk levels of eutrophication, seeking to guide public policies, have led the ministries in charge of the... |
| Tipo: Text |
Palavras-chave: Eutrophication; Nitrogen; Phosphorus; Algae bloom; Land-sea continuum; Diffuse pollution. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00456/56734/58551.pdf |
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| Menesguen, Alain; Desmit, Xavier; Duliere, Valerie; Lacroix, Genevieve; Thouvenin, Benedicte; Thieu, Vincent; Dussauze, Morgan. |
| Since 1950, increase in nitrogen (N) and phosphorus (P) river loadings in the North-East Atlantic (NEA) continental seas has induced a deep change in the marine coastal ecosystems, leading to eutrophication symptoms in some areas. In order to recover a Good Ecological Status (GES) in the NEA, as required by European Water Framework Directive (WFD) and Marine Strategy Framework Directive (MSFD), reductions in N- and P-river loadings are necessary but they need to be minimal due to their economic impact on the farming industry. In the frame of the “EMoSEM” European project, we used two marine 3D ecological models (ECO-MARS3D, MIRO&CO) covering the Bay of Biscay, the English Channel and the southern North Sea to estimate the contributions of various... |
| Tipo: Text |
Palavras-chave: Marine eutrophication; Ecosystem modelling; Nutrient reduction scenario; Linear optimization; Good ecological status; EU policies. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00426/53774/54661.pdf |
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| Del Amo, Yolanda; Le Pape, Olivier; Treguer, Paul; Queguiner, Bernard; Menesguen, Alain; Aminot, Alain. |
| The chemical factors (inorganic nitrogen, phosphate, silicic acid) that potentially or actually control primary production were determined for the Bay of Brest, France, a macrotidal ecosystem submitted to high-nitrate-loaded freshwater inputs (winter nitrate freshwater concentrations >700 mu M, Si:N molar ratio as low as 0.2, i.e. among the lowest ever published). Intensive data collection and observations were carried out from February 1993 to March 1994 to determine the variations of physical [salinity, temperature, photosynthetically active radiation (PAR), freshwater discharges] and chemical (oxygen and nutrients) parameters and their impacts on the phytoplankton cycle (fluorescence, pigments, primary production). With insufficient PAR the winter... |
| Tipo: Text |
Palavras-chave: Coastal ecosystem; Phytoplankton dynamics; Macrotidal; Nutrient limitation; Silicon; Eutrophication. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00337/44782/44588.pdf |
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| Hamon, Dominique; Blanchard, Michel; Houlgatte, Eric; Blanchet, Aline; Gaffet, Jean-dominique; Cugier, Philippe; Menesguen, Alain; Bassoullet, Philippe; Cann, Philippe; Domalain, David; Haubois, Anne-gaelle. |
| La crépidule (Crepidula fornicata), mollusque gastéropode de la famille des Calyptraeidés, originaire de la côte atlantique d'Amérique du nord, a été introduite accidentellement sur le littoral français en plusieurs étapes (Blanchard, 1995, 1997). La plus importante d'entre elles, au début des années 70, est liée à l'importation massive de l'huître japonaise (Crassostrea gigas), en remplacement de l'huître portugaise (Crassostrea angulata) décimée par une épizootie. Cette espèce opportuniste a notamment proliféré au voisinage des principaux bassins ostréicoles de la Manche et de l'Atlantique. C'est en particulier le cas des zones conchylicoles infralittorales du golfe normano-breton où des évaluations de stocks font état de plusieurs centaines de milliers... |
| Tipo: Text |
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| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/00032/14295/11574.pdf |
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| Menesguen, Alain. |
| Excessive proliferation of UIva sp. (Chlorophyta) during spring and summer was responsible for increasing injuries to recreational use of several beaches of Britanny (France) during the last decade. These worldwide mass blooms are well known in eutrophicated lagoons (Venice, Tunis... ), but look paradoxical along open beaches with large tidal range and weak terrestrial nutrients inputs. Numerical modelling of the coupled physical and biological aspects clearly explains the Ulva mass blooms by the dynamical trapping of water masses in bays where tidal residual drift vanishes, and shows the main responsability of the increase of nitrogen inputs (of agricultural sources) in triggering the recent magnification of a natural phenomenon. |
| Tipo: Text |
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| Ano: 1990 |
URL: https://archimer.ifremer.fr/doc/00480/59125/61753.pdf |
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| 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 |
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| Menesguen, Alain. |
| Following lakes and rivers, a lot of estuaries (during the last twenty years) and shallow coastal zones (during the last decade) have been severely eutrophicated because of the too much increasing loads of nitrogen and phsophorus. In situ stutdy and numerical modelling of two french case studies bring some explanation to the facts that, in some sites, enrichment turns into green macroalgal proliferation whereas, in others, mass blooms of phytoplankton are induced. Whatever the case may be, the prominent role of the residence time of water in the enriched zone has been proven. In open coastal ecosystems, the difficulty in determining this residence time as well as the limiting factor (nitrogen, or phosphorus, or light) lowers considerably the reliability of... |
| Tipo: Text |
Palavras-chave: Eutrophisation côtière; Elément limitant; Temps de résidence; Modèles hydrodynamiques; Modèles écologiques; Coastal eutrophication; Limiting factor; Residence time; Hydrodynamical models; Ecological models. |
| Ano: 1992 |
URL: http://archimer.ifremer.fr/doc/00423/53416/54295.pdf |
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| Stanisiere, Jean-yves; Mazurie, Joseph; Bouget, Jean-francois; Langlade, Aime; Gabellec, Raoul; Retho, Michael; Quinsat, Kevin; Leclerc, Emilie; Cugier, Philippe; Dussauze, Morgan; Menesguen, Alain; Dumas, Franck; Gohin, Francis; Augustin, Jean-marie; Ehrhold, Axel; Sinquin, Jean-marc; Goubert, Evelyne; Dreano, Alain. |
| The project “Risco”, supported by the “Pôle Mer” and funded by the Regional Council of Brittany, deals with specific risks of mortality of oysters, Crassostrea gigas, cultivated on the bottom, in a subtidal bay of South Brittany : the bay of Quiberon (56, France). Massive mortalities of oysters were reported in summer 2006 in this bay, exclusively located in the deep muddy area with a positive gradient eastward. A validated biogeochemical model was applied in order to simulate the dissolved oxygen over 2000-2006 : it revealed several episodes of hypoxia, more or less intense according to years, but with the same spatial distribution. This approach proved 2006 to be the most hypoxic year since 2000. The hypoxia was due to a rare conjunction of 3 factors :... |
| Tipo: Text |
Palavras-chave: Baie Quiberon; Crassostrea gigas; Huître; Mortalité; Croissance; Hypoxie; Oxygène; Modèle; Upwelling; Loire; Vilaine; Quiberon; Crassostrea gigas; Oyster; Mortality; Growth; Hypoxia; Oxygen; Model; DEB; Upwelling; Loire; Vilaine. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00180/29131/27535.pdf |
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| Registros recuperados: 63 | |
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