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| Registros recuperados: 28 | |
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| Lunven, Michel; Guillaud, Jean-francois; Crassous, Marie Pierre; Youenou, Agnes; Gohin, Francis; Huret, Martin; Danielou, Marie-madeleine; Kerouel, Roger; Labry, Claire; Aminot, Alain. |
| Inscrite dans le cadre du Grand Défi Golfe de Gascogne, la campagne VILOIR a été réalisée du 19 au 26 Juin 2003 à bord du Côtes de la Manche avec pour objectif l’étude en période estivale des structures hydrologiques et phytoplanctoniques des panaches de la Loire et de la Vilaine. Elle fait suite, sur la même thématique, à la campagne hivernale NUTRIGAS (2001) et à la campagne printanière GASPROD (2002). |
| Tipo: Text |
Palavras-chave: Surveillance; Littoral; Phytoplancton; Phycotoxines; Bretagne; Pays de Loire. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/00144/25494/23648.pdf |
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| Guillaud, Jean-francois. |
| Cette étude, engagée à la demande de l'Agence Financière de Bassin Seine-Normandie dans le cadre du SAUM de l'estuaire de la Seine, a deux objectifs principaux qui sont : - de définir les flux et le cycle des sels nutritifs dans l'estuaire de la Seine, ainsi que leurs variations, dans le temps et dans l'espace, en fonction des conditions hydrologiques. - d'évaluer les principaux facteurs chimiques, physiques et biologiques, régissant la distribution de l'oxygène dissous dans l'estuaire et ceci en vue de l'établissement d'un modèle mathématique de l'oxygène dissous. |
| Tipo: Text |
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| Ano: 1980 |
URL: http://archimer.ifremer.fr/doc/00104/21520/19101.pdf |
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| Menesguen, Alain; Cugier, Philippe; Loyer, Sophie; Vanhoutte Brunier, Alice; Hoch, Thierry; Guillaud, Jean-francois; Gohin, Francis. |
| The general trend in ecosystem modelling is to improve the spatial resolution by shifting from rough box-models to fine 3D models. Despite the continuous speeding-up of computing, 3D models involving numerous state variables may remain intractable, especially for parameter calibration, when processes with long half-life periods (i.e, from years to decades) are introduced, such as the behaviour of organic matter in sediment and population dynamics of benthic species. In these cases, a first approach can be provided by fast-running box-models, if they take into account the most crucial hydrodynamic properties of the system. In a macrotidal shelf sea such as the English Channel, the long-term horizontal transport can be summarized by the tidal residual... |
| Tipo: Text |
Palavras-chave: English Channel; Stratification; Diatom/dinoflagellate succession; 3D model; Layered box model. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2315.pdf |
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| Gohin, Francis; Lampert, Luis; Guillaud, Jean-francois; Herbland, Alain; Nezan, Elisabeth. |
| A phytoplankton bloom was observed in late winter 2000, on the continental shelf offshore of southern Brittany, in northwestern Bay of Biscay. This bloom appeared initially along the 120-m isobath, in stratified and clear waters, at the interface between the oceanic water and the plumes of southern Brittany rivers (mainly the Loire and Vilaine). The development of the bloom was triggered by favourable meteorological conditions, characterised by solar irradiance reaching the maximum level expected for that period of the year. Outside of the bloom area, the phytoplankton photosynthesis was irradiance limited: inshore, because of the stronger attenuation of the light; offshore, because of the weak stratification. The hydrological conditions at the onset of... |
| Tipo: Text |
Palavras-chave: Bay of Biscay; Coscinodiscus; Algal bloom; Phytoplankton; Ocean colour; Satellite sensing. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/2003/publication-463.pdf |
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| Repecaud, Michel; Degres, Yves; Bernard, Nathalie; Allenou, Jean-pierre; Aoustin, Yannick; Arrondeau, Jean-pierre; Bouget, Jean-francois; Bucas, Karenn; Daniel, Anne; Guillaud, Jean-francois; Hamon, Michel; Jegou, Paul; Laes, Agathe; Le Roux, Dominique; Le Piver, David; Quemener, Loic; Rolin, Jean-francois; Rudelle, Tiphaine; Legrand, Jacques; Vuillemin, Renaud. |
| The automated monitoring of physico-chemical parameters in the coastal zone has been using large buoys and fixed infrastructures. A better understanding of many estuaries is needed in order to fulfil the agenda and requirements of the European Water Framework Directive. In order to address the fluxes of nutrients as well as algal blooms and low oxygen events, the "TROPHIMATIQUE" project has developed a new generation of instruments able to be deployed in sea waters. The smaller size of the new instruments is intended to facilitate the maintenance. A new multi-parameter probe has been developed. The measurements of all nutrients are performed thanks to the CHEMINI flow injection analysers for nitrate, ammonia, silicate and phosphate. A sampler using similar... |
| Tipo: Text |
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| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00107/21807/20276.pdf |
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| Abarnou, Alain; Guillaud, Jean-francois; Miossec, Laurence; Batt, Agnes. |
| Chlorination of wastewater prior to effluent discharge into the sea is used as disinfecting treatment to preserve salubrity of the coastal marine environment wich is necessary for such activities as shellfish-farming and nautical sports. The disinfecting capacity of chlorine results from its oxydizing property which gives rise to various chemical reactions with constituents present in wastes. ln wastewaters, highly loaded with organic matter and ammonia, monochloramine is the main active chlorine species. Due to organic matter oxydation, thèse active chlorine species rapidly disappear by transformation into non toxic chloride. However, a very sm ail part of the initial chlorine dose can be found as stable and toxic chloroorganics. Monochloramine is also... |
| Tipo: Text |
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| Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/00173/28438/26772.pdf |
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| Pommepuy, Monique; Dupray, Elisabeth; Guillaud, Jean-francois; Derrien, A; L'Yavanc, Jacky; Cormier, M. |
| The behaviour of fecal bacteria was investigated in a turbid estuary which is also a shellfishing area. Sediments are polluted by sewage by the way of settlement, fecal bacteria mixed with estuarine water being able to survive a very long time (T90 are about several days). By measuring the increase of salt tolerance of the strains grown in natural estuarine organic matter, it was demonstrated that Escherichia coli is able to support the salinity of coastal water. Moreover, because light penetration is obstructed by suspended matter, the solar bactericidal effect is very low. A close relationship between T90 and light intensity received by the bacteria is found. These mechanisms can explain the low die-off rate found in turbid areas. |
| Tipo: Text |
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| Ano: 1991 |
URL: http://archimer.ifremer.fr/doc/00267/37860/35941.pdf |
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| Guillaud, Jean-francois; Aminot, Alain; Delmas, Daniel; Gohin, Francis; Lunven, Michel; Labry, Claire; Herbland, Alain. |
| Seasonal variations in nutrient inputs are described for the main rivers (Loire and Vilaine) flowing into the northern Bay of Biscay. The river plumes are high in N/P ratio in late winter and spring, but not in the inner plume during the summer. Conservative behavior results in most nutrients entering the estuary and eventually reaching the coastal zone. Temporal and spatial aspects of phytoplankton growth and nutrient uptake in the northern Bay of Biscay distinguish the central area of salinity 34 from the plume area. The first diatom bloom appears offshore in late winter, at the edge of the river plumes, taking advantage of haline stratification and anticyclonic "weather windows." In spring, when the central area of the northern shelf is... |
| Tipo: Text |
Palavras-chave: Northern Bay of Biscay; Phytoplankton; Continental shelf; Riverine inputs; Nutrients. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2354.pdf |
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| Lunven, Michel; Guillaud, Jean-francois; Youenou, Agnes; Crassous, Marie-pierre; Berric, Roger; Le Gall, Erwan; Kerouel, Roger; Labry, Claire; Aminot, Alain. |
| Many studies in coastal areas have shown the existence of thin chemical and biological layers. Their thickness and vertical extension are mainly controlled by hydrological and physical forcing. An accurate description of the phytoplankton communities growing within these layers is difficult to obtain without a well-adapted sampling system. A new Fine Scale Sampler (FSS) has been designed in Ifremer in order to study phytoplankton distribution and associated dissolved properties in high stratified water column. This FSS consists in a vertical array of 15 sampling bottles, horizontally laid with 20 cm intervals. Data acquired from a CTD and Fluorescence probe provide a precise FSS positioning at the depth of highest density gradient or at chlorophyll a... |
| Tipo: Text |
Palavras-chave: Surveillance; Littoral; Phytoplancton; Phycotoxine. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/00144/25493/23647.pdf |
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| Billen, Gilles; Cugier, Philippe; Garnier, Josette; Menesguen, Alain; Guillaud, Jean-francois; Durand, I. |
| Le processus d'eutrophisation des milieux marins côtiers, et le développement épisodiques de dinoflagellés qui en est une des manifestations, dépend de manière complexe de l'équilibre des flux d'azote, de phosphore et de silice en provenance des milieux terrestres du bassin versant. Ceux ci sont déterminés par la manière dont les activités humaines sur le bassin versant interagissent avec les processus naturels. La possibilité de prévoir l'effet sur l'eutrophisation marine des mesures prises pour l'amélioration de la qualité des eaux continentales dépend donc à la fois de notre connaissance du fonctionnement des milieux marins et de celui des bassins versants. En vue de développer les outils de modélisation nécessaire pour prévoir l'Etat de la Baie de... |
| Tipo: Text |
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| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/00106/21695/19274.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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| Lunven, Michel; Guillaud, Jean-francois; Youenou, Agnes; Crassous, Marie-pierre; Berric, Roger; Le Gall, Erwan; Kerouel, Roger; Labry, Claire; Aminot, Alain. |
| A new Fine Scale Sampler (FSS) was designed and used in the Loire River plume (Bay of Biscay, France) in order to study phytoplankton distribution in highly stratified water columns. The FSS consists of a linear array of 15 sampling bottles, set horizontally at 20 cm intervals. Data acquired from the CTD and fluorescence probe of the FSS enable it to be precisely positioned at the depth of the highest density gradient or at the chlorophyll a maximum. The FSS made it possible to investigate fine scale vertical distribution of phytoplankton and relationships with water density, nutrient concentrations or light availability, for spring and summer conditions. Under spring conditions, the entire upper layer exhibited a dominant diatom population (Chaetoceros... |
| Tipo: Text |
Palavras-chave: Plankton patchiness; Density discontinuity; Sampling; Thin layer; Nutrients; Phytoplankton. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-533.pdf |
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| Aminot, Alain; Guillaud, Jean-francois; Kerouel, Roger. |
| The data of hydrology, nutrients and chlorophyll obtained in the Bay of Seine over the period 1978-1994, from 14 océanographie cruises, are synthetised and illustrated by an atlas. The Bay is a typical example of a coastal area influenced by a large river. In winter, the nutrient input is drained off into the eastern Channel. In spring, nutrients are consumed intensively. Silicate is the first that drops to limiting levels. The spring bloom generally begins in the centre-east of the Bay. Chlorophyll a can reach up to 40-70 µg/l during the year, values typical of eutrophic coastal areas. Despite the regular increase of nitrogen inputs, the biomass (as chlorophyll) has not significantly changed over a fifteen year period. |
| Tipo: Text |
Palavras-chave: Chlorophyll; Nutrients; Hydrology; Bay of Seine; Chlorophylle; Nutriments; Hydrologie; Baie de Seine. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/1997/rapport-1428.pdf |
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| Registros recuperados: 28 | |
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