|
|
|
| Registros recuperados: 63 | |
|
| |
|
| |
|
|
| Menesguen, Alain; Hoch, Thierry. |
| This paper presents the general framework of an ecological model of the English Channel. The model is a result of combining a physical sub-model with a biological one. in the physical submodel, the Channel is divided into 71 boxes and water fluxes between them are calculated automatically. A 2-layer, vertical thermohaline model was then linked with the horizontal circulation scheme. This physical sub-model exhibits thermal stratification in the western Channel during spring and summer and haline stratification in the Bay of Seine due to high flow rates from the river. The biological sub-model takes 2 elements, nitrogen and silicon, into account and divides phytoplankton into diatoms and dinoflagellates. Results from this ecological model emphasize the... |
| Tipo: Text |
Palavras-chave: Ecological box-model; Thermohaline stratification; English Channel; Primary production. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00337/44790/44479.pdf |
| |
|
| |
|
|
| Menesguen, Alain; Gohin, Francis. |
| Accumulation of heat, or dissolved substances (nutrients, pollutants, etc.), or fine suspended particles in a water body is a key process in the functioning of aquatic ecosystems and their resistance to perturbations. In complex and wide open environments such as marine ecosystems, net accumulation is not only linked to the local renewal capacity of the water body, but also to the partial recirculation of water due to convective cells of various sizes. The English Channel, which can be considered as mainly dominated by tidal movements, exhibits such a complex quasi-permanent long-term circulation, made of a central "river" bordered with a lot of nested gyres. Here, we show that structures visible on satellite images of SST (Sea Surface Temperature),... |
| Tipo: Text |
Palavras-chave: Remote sensing; Suspended Particulate Matter; Chlorophyll; SST; Retention structures; Tidal residual circulation; Steady state model; English Channel. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-2181.pdf |
| |
|
| |
|
|
| 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 |
| |
|
|
| Heral, Maurice; Bacher, Cedric; Razet, Daniel; Prou, Jean; Deslous-paoli, Jean-marc; De Pontual, Helene; Raillard, Olivier; Ravail, Brigitte; Maestrini, Serge; Mornet, Francoise; Menesguen, Alain; Sautour, Benoit; Robert, Jean-michel. |
| Les termes du contrat passé entre le Fond de la Recherche et de la Technologie et l'IFREMER précisent qu ele programmer a pour objectif une gestion rationnelle du milieu conchylicole avec notamment une mise au point de modèles (voir notification de l'aide en annexe). Un premier modèle appelé modèle global par analogie avec les modèles de pêche met en évidence la limite de la capacité trophique du bassin de Marennes-Oléron pour les huîtres cultivées. Un modèle analytique avec un modèle physique simple permet dans un premier temps de développer un modèle de croissance des huîtres en fonction de la nourriture disponible et d'effectuer des simulations qui confirment l'influence du stock sur les performances de croissance des bivalves. Un troisième approche... |
| Tipo: Text |
Palavras-chave: Modélisation; Production; Biomasse; Huîtres creuses; Crassostrea gigas; Capacité biotique; Bassin de Marennes Oléron. |
| Ano: 1989 |
URL: http://archimer.ifremer.fr/doc/00048/15904/13332.pdf |
| |
|
|
| Menesguen, Alain; Dussauze, Morgan; Lecornu, Fabrice; Dumas, Franck; Thouvenin, Benedicte. |
| Nitrate loadings to the French coastal waters of the Bay of Biscay and the English Channel have increased from 5 to 10 times during the four last decades, due to runoff on intensively fertilized agricultural watersheds. Eutrophication of this coastal zone is now a recurrent problem, with wellknown direct impacts (Ulva “green tides” on beaches, excessive phytoplanktonic blooms responsible for “coloured waters” and bottom hypoxia events offshore), but also indirect enhancement of the toxicity of some phytoplankton species, caused for instance by increased N:Si ratio in the coastal sea. In order to better guide the decision makers about nutrient loading reduction, Ifremer uses the so-called ECO-MARS3D biogeochemicalhydrodynamical model to simulate the present... |
| Tipo: Text |
|
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00197/30797/29166.pdf |
| |
|
|
| Desmit, X.; Thieu, V.; Billen, G.; Campuzano, F.; Duliere, V.; Garnier, J.; Lassaletta, L.; Menesguen, Alain; Neves, R.; Pinto, L.; Silvestre, M.; Sobrinho, J. L.; Lacroix, G.. |
| Marine eutrophication in the North-East Atlantic (NEA) strongly relies on nutrient enrichment at the river outlets, which is linked to human activities and land use in the watersheds. The question is whether human society can reduce its nutrient emissions by changing land use without compromising food security. A new version of Riverstrahler model (pyNuts-Riverstrahler) was designed to estimate the point and diffuse nutrient emissions (N, P, Si) to the rivers depending on land use in the watersheds across a large domain (Western Europe agro-food systems, waste water treatment). The loads from the river model have been used as inputs to three marine ecological models (PCOMS, ECO-MARS3D, MIRO&CO) covering together a large part of the NEA from the Iberian... |
| Tipo: Text |
Palavras-chave: North-East Atlantic; Eutrophication; Model scenarios; Land-sea continuum; Land use; Pristine; Management support. |
| Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00438/55007/56426.pdf |
| |
|
|
| 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 |
| |
|
|
| 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 |
| |
|
|
| Ferreira, Joao G.; Andersen, Jesper H.; Borja, Angel; Bricker, Suzanne B.; Camp, Jordi; Da Silva, Margarida Cardoso; Garces, Esther; Heiskanen, Anna-stiina; Humborg, Christoph; Ignatiades, Lydia; Lancelot, Christiane; Menesguen, Alain; Tett, Paul; Hoepffner, Nicolas; Claussen, Ulrich. |
| In 2009, following approval of the European Marine Strategy Framework Directive (MSFD, 2008/56/EC), the European Commission (EC) created task groups to develop guidance for eleven quality descriptors that form the basis for evaluating ecosystem function. The objective was to provide European countries with practical guidelines for implementing the MSFD, and to produce a Commission Decision that encapsulated key points of the work in a legal framework. This paper presents a review of work carried out by the eutrophication task group, and reports our main findings to the scientific community. On the basis of an operational, management-oriented definition, we discuss the main methodologies that could be used for coastal and marine eutrophication assessment.... |
| Tipo: Text |
Palavras-chave: Eutrophication; Chlorophyll; Dissolved oxygen; Harmful algae; Marine; Coastal; Assessment methods; Europe; Marine Strategy Framework Directive; Water Framework Directive. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00039/15055/12609.pdf |
| |
|
|
| Menesguen, Alain; Dreves, Luc. |
| The demographic structure of stable populations is usually modelled by a simple exponential decay mode. For 3 mollusc species, this model has been improved by taking inlo account monthly sea-temperature anomalies calculated on a 20 yr daily temperature chronicle. For the 3 species examined, Tapes rhomboïdes, Glycymeris glycymeris and Spisula ovalis, from the southern part of the Western English Channel, only temperature anomalies during the 2 mo following the major spawning period were positively eorrelated with density anomalies, probably in eonneetion with larval stage sensitivity. Comparison of temperature anomalies and mean annual growth va riability suggests an apparent positive effeet of temperature during autumn or winter months, significant for T.... |
| Tipo: Text |
|
| Ano: 1987 |
URL: http://archimer.ifremer.fr/doc/00155/26639/24880.pdf |
| |
|
|
| Grangere, Karine; Menesguen, Alain; Lefebvre, Sébastien; Bacher, Cedric; Pouvreau, Stephane. |
| It is well known that temporal changes in bivalve body mass are strongly correlated with temporal variations in water temperature and food supply. In order to study the influence of the year-to-year variability of environmental factors on oyster growth, we coupled a biogeochemical sub-model, which simulates trophic resources of oysters (i.e. phytoplankton biomass via chlorophyll a), and an ecophysiological sub-model, which simulates growth and reproduction (i.e. gametogenesis and spawning), using mechanistic bases. The biogeochemical sub-model successfully simulated phytoplankton dynamics using river nutrient inputs and meteorological factors as forcing functions. Adequate simulation of oyster growth dynamics requires a relevant food quantifier compatible... |
| Tipo: Text |
Palavras-chave: Baie des Veys; Normandy; France; Physiological Status; Phytoplankton Carbon Concentration; Food Supply; Temperature; Dynamic Energy Budget model; Biogeochemical Model. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6809.pdf |
| |
|
| |
|
|
| 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 |
|
| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/00032/14295/11574.pdf |
| |
|
|
| Savina, Marie; Menesguen, Alain. |
| Paphia rhombofdes is an infaunal filter-feeding bivalve, particularly widespread and abundant in the English Channel. In order to investigate the influence of the growth-related post-settlement processes on its distribution, a spatial growth model was developed and linked to an existing ecological model of the English Channel. This model was partially parameterized on the basis of a specific ecophysiological experimental study, and calibrated with growth data collected in the "Golfe Normand-Breton" (GNB), a region of the English Channel. Compared to the actual distribution of P. rhomboides, the results suggest a strong influence of the growth-related processes on the distribution of the species: particularly, the extremely low growth obtained with the... |
| Tipo: Text |
Palavras-chave: Distribution; Meroplanktonic invertebrates; Ecophysiology; Growth model; English channel; Paphia rhomboides. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3115.pdf |
| |
|
|
| Charria, Guillaume; Repecaud, Michel; Quemener, Loic; Menesguen, Alain; Rimmelin-maury, Peggy; L'Helguen, Stephane; Beaumont, Laurence; Jolivet, Aurelie; Morin, Pascal; Mace, E; Lazure, Pascal; Le Gendre, Romain; Jacqueline, Franck; Verney, Romaric; Marie, Louis; Jegou, Paul; Le Reste, Serge; Andre, Xavier; Dutreuil, Vincent; Regnault, Jean-pierre; Jestin, Herve; Lintanf, Herve; Pichavant, Pascal; Retho, Michael; Allenou, Jean-pierre; Stanisiere, Jean-yves; Bonnat, Armel; Nonnotte, Lidwine; Duros, Wenceslas; Tarot, Stephane; Carval, Thierry; Le Hir, Pierre; Dumas, Franck; Vandermeirsch, Frederic; Lecornu, Fabrice. |
| To design a prototype for an Integrated Ocean Observing System (IOOS), at least three components are mandatory: a modeling platform, an in situ observing system and a structure to collect and to disseminate the information (e.g. database, website). The PREVIMER project followed this approach and in order to sustain model applications, PREVIMER has developed, funded and organized part of in situ observing networks in the Bay of Biscay and the Channel. For a comprehensive system, focus was addressed on fi xed platforms (MAREL MOLIT, MAREL Iroise, Island network and D4 for sediment dynamics), ships of opportunity (RECOPESCA program and FerryBoxes), and coastal profi lers (ARVOR-C/Cm). Each system is briefl y described and examples of scientifi c results... |
| Tipo: Text |
|
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00197/30785/29143.pdf |
| |
|
|
| 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 |
| |
| Registros recuperados: 63 | |
|
|
|
