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| Registros recuperados: 37 | |
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| Plus, Martin; Chapelle, Annie; Menesguen, Alain; Deslous-paoli, Jean-marc; Auby, Isabelle. |
| A numerical deterministic model for a seagrass ecosystem (Zostera noltii meadows) has been developed for the Thau lagoon. It involves both above- and belowground seagrass biomasses, nitrogen quotas and epiphytes. Driving variables are light intensity, wind speed, rain data and water temperature. This seagrass model has been coupled to another biological model in order to simulate the relative contributions of each primary producer to: (i) the total ecosystem production, (ii) the impact on inorganic nitrogen and (iii) the fluxes towards the detritus compartment. As a first step in the modelling of seagrass beds in the Thau lagoon, the model has a vertical structure based on four boxes (a water box on top of, three sediment boxes) and the horizontal... |
| Tipo: Text |
Palavras-chave: Thau lagoon; Nitrogen cycle; Oxygen cycle; Box model; Seagrass ecosystem. |
| Ano: 2003 |
URL: https://archimer.ifremer.fr/doc/2003/publication-461.pdf |
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| Chapelle, Annie; Menesguen, Alain; Deslous-paoli, Jean-marc; Souchu, Philippe; Mazouni, Nabila; Vaquer, André; Millet, Bertrand. |
| An ecosystem model based on nitrogen cycling and oxygen has been developed for the Thau lagoon. It takes into account the specific features of this Mediterranean lagoon, a semi-confined system with watershed inputs and oyster farming. The ecosystem model uses currents calculated by a two-dimensional hydrodynamic model and integrated into a box model. This model is compared with a year survey data and used to estimate nitrogen and oxygen fluxes between the different ecosystem compartments. The yearly simulation shows that the ecosystem behavior is driven by meteorological forcing, especially rain which causes watershed inputs. These inputs trigger microphytoplankton growth, which is responsible for new primary production. During dry periods, nitrogen is... |
| Tipo: Text |
Palavras-chave: Oxygen; Nitrogen; Oysters; Primary production; Box model; Lagoon ecosystem. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/2000/publication-725.pdf |
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| Chapelle, Annie; Le Bec, Claude; Siano, Raffaele; Caradec, Florian; Andrieux, Francoise. |
| Suite à l’efflorescence de grande ampleur d’Alexandrium minutum et des événements toxiques associés en Rade de Brest en 2012, un projet a été monté avec la Région dans le cadre du développement du port de Brest, pour élucider les contrôles de cette efflorescence. De juillet à août 2013, l’Ifremer a organisé un échantillonnage serré dans l’estuaire de Daoulas, zone la plus touchée en 2012 (rapport d’avancement n°1). Une autre partie de ce projet vise à la détection (rapport d’avancement n°2) et à la quantification (rapport d’avancement n°3) des traces biologiques d’A. minutum dans les sédiments de surface en différentes stations de la Rade de Brest présentant des caractéristiques sédimentaires différentes. Pour la détection des traces biologiques (ADN... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00191/30231/28647.pdf |
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| Chapelle, Annie. |
| La baie de Vilaine, d'une superficie de 200 km², est située au sud de la Bretagne (fig. 1). Son bassin versant (10 400 km²) s'étend sur un tiers de la Bretagne ; il est drainé principalement par le fleuve Vilaine et son affluent l'Oust. L'importance des activités agricoles, et l'agglomération de Rennes sont responsables de teneurs élevées en azote et phosphore dans le fleuve Vilaine, le situant à la limite supérieure de l'eutrophie (QUEGUINER, 1988 a). La construction du barrage d'Arzal (1970), prévu pour assécher la zone marécageuse autour de Redon et établir une réserve d'eau potable à Férel, a réduit l'estuaire de la Vilaine d'une quarantaine de kilomètres. Il en résulte un déplacement des fonctions de dégradation de la matière organique vers la baie... |
| Tipo: Text |
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| Ano: 1989 |
URL: http://archimer.ifremer.fr/doc/00104/21526/19107.pdf |
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| Bejaoui, B; Harzallah, A; Moussa, M; Chapelle, Annie; Solidoro, C. |
| This study deals with the use of a multivariate analysis method in order to understand the functioning of the Bizerte lagoon ecosystem. A set of hydrobiological parameters was collected during 10 monthly campaigns in 2004. A variant of the EOF (Empirical Orthogonal Function) technique is used to examine hydrobiological variability modes in this lagoon. The permanent features characterising the lagoon are obtained by applying the EOF technique to data after removing the annual cycle. Two major modes were obtained. The first one shows a contrast between the northern sector of the lagoon, influenced by the Mediterranean Sea, and the southern one influenced by continental waters. This mode is mostly prominent for temperature and salinity. The second mode shows... |
| Tipo: Text |
Palavras-chave: Nutrient cycles; EOF analysis; Bizerte lagoon. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4808.pdf |
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| Labry, Claire; Erard-le Denn, Evelyne; Chapelle, Annie; Fauchot, Juliette; Youenou, Agnes; Crassous, Marie-pierre; Le Grand, Jacqueline; Lorgeoux, Benedicte. |
| The understanding of the dominance of one species with respect to others is a pertinent challenge in HAB growth dynamics studies and the nutrient supply mode is one of the factors potentially involved. The competition for phosphorus (P) between a toxic species, Alexandrium minutum, and a non-toxic species, Heterocapsa triquetra, was studied (1) along a gradient of P depletion, (2) testing different P depletion degrees before a single PO4 supply and (3) experimenting different PO4 supply frequencies. In conditions Of PO4 depletion, H. triquetra stopped growing after two days both in monospecific and mixed batch cultures whereas A. minutum grew progressively from day 2 until the end of the experiment. This time-lag growth of A. minutum is associated to its... |
| Tipo: Text |
Palavras-chave: Semi continuous culture; Batch culture; Ecophysiology; Pulse; Phosphorus storage; Dinoflagellates; Heterocapsa triquetra; Alexandrium minutum. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4067.pdf |
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| Guallar, Carles; Bacher, Cedric; Chapelle, Annie. |
| The dinoflagellate Alexandrium minutum is a toxic bloom-forming species distributed worldwide. The mechanisms driving and promoting the species blooms and their toxicity are studied and presented here. Most previously published work focuses on local and/or short-term scales. In this study, a broad temporal and spatial approach is addressed using time series covering several sites over several years and combining environmental variables and A. minutum abundances from the French English Channel − Atlantic coasts. Data were explored by means of phenology and threshold analysis. The A. minutum bloom characteristics are defined. Only one bloom per year is measured and it may reach more than a million of cells L−1. Bloom period extends from April to October and... |
| Tipo: Text |
Palavras-chave: Alexandrium minutum; PSP toxicity; HAB; Bloom phenology; Threshold analysis; Monitoring long time-series. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00390/50130/51076.pdf |
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| Labry, Claire; Erard-le Denn, Evelyne; Chapelle, Annie; Youenou, Agnes; Crassous, Marie Pierre; Martin-jezequel, Véronique; Le Grand, Jacqueline. |
| Suite à un premier criblage des facteurs environnementaux favorables à la croissance d'Alexandrium minutum comparativement à celle d'une espèce compétitrice en rivière de Penzé, Heterocapsa triquetra (rapport ART3 2002-2003) cette étude vise à préciser et quantifier les réponses physiologiques respectives des deux espèces à différentes conditions d'apports en phosphate (taux de croissance, vitesse d'assimilation des phosphates, capacité à stocker le phosphore intracellulaire). Elle montre qu'Alexandrium minutum a plutôt une stratégie de « stockage », capable d'assimiler rapidement le phosphate après un apport mais le stockant pour une meilleure croissance ultérieure quand la ressource sera à nouveau épuisée. Comparativement, Heterocapsa triquetra aurait,... |
| Tipo: Text |
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| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/00105/21598/19178.pdf |
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| Menesguen, Alain; Aminot, Alain; Belin, Catherine; Chapelle, Annie; Guillaud, Jean-francois; Joanny, Michel; Lefebvre, Alain; Merceron, Michel; Piriou, Jean-yves; Souchu, Philippe. |
| In order to be able to count the cases of coastal eutrophication and to propose methods to monitor as well as to reduce these phenomena, first of all it is necessary to precisely define the word eutrophication itself. Instead of the strict etymological definition, that is to say a progression of the enrichment of a medium, we will rather retain the concept of a state enriched at a point such as it causes harmful effects on the ecosystem, and nuisances to man's activities. Based on the average chemical equations of the organic matter synthesis/degradation in the sea, this operational definition thus puts forwards the harmful consequences of enrichment, i.e. the production of an excessive algal biomass, sometimes unbalanced from the point of view of... |
| Tipo: Text |
Palavras-chave: Alexandrium; Phaeocystis; Monostroma; Ulva; Dilution plume; Water trapping; Anoxia; Nitrogen and phosphorus loadings; Red tides; Phytoplankton blooms; Green tides; Eutrophication; Alexandrium; Phaeocystis; Monostroma; Ulva; Panache de dilution; Confinement; Anoxie; Phosphate; Nitrate; Apports terrigènes; Eaux colorées; Blooms phytoplanctoniques; Marées vertes; Eutrophisation. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/2001/rapport-22.pdf |
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| Chapelle, Annie; Mesnage, Valérie; Mazouni, Nabila; Deslous-paoli, Jean-marc; Picot, Bernadette. |
| A simulation of nitrogen and phosphorus exchanges for the sediment-water interface is presented, The aim of the sttudy is to understand the dynamic behaviour of an eutrophie coastal lagoon (Thau, France), ln situ experiments were performed to estimate the different pools of nitrogen and phosphorus in the water column and in the sediment. The diffusive fluxes between them were also estimated. A numerical mode1, simulating nitrogen and phosphorus cycles, was developed and calibrated with data recorded .at two seasons (winter and summer). This study leads to the conclusion that is necessary to know the different pools of nitrogen and phosphorus in order to estimate which fraction is bioavailable and the rate of nutrient exchange between sediment and water. It... |
| Tipo: Text |
Palavras-chave: Modèle; Phosphore; Azote; Sédiment; Ecosystème conchylicole; Modelling; Phosphorus; Nitrogen; Sediment; Shellfish ecosystem. |
| Ano: 1994 |
URL: http://archimer.ifremer.fr/doc/00039/15026/12360.pdf |
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| Chapelle, Annie. |
| Le phytoplancton, de par sa diversité et sa fonction de producteur primaire, est le support de l’ensemble des réseaux trophiques des eaux douces et marines. Il est aussi responsable de la production de la moitié de l’oxygène de notre atmosphère. Il participe à la productivité des écosystèmes côtiers et il témoigne également de leur dégradation. La modélisation numérique permet d’appréhender les multiples liens entre le phytoplancton et les autres composantes de l’écosystème côtier et de centrer le modèle sur les questions posées. Dans ce manuscrit sont abordés les principes de modélisation du phytoplancton dans les écosystèmes côtiers, et les applications du modèle à l’étude de l’eutrophisation et des proliférations de phytoplancton toxique, dans un... |
| Tipo: Text |
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| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00360/47141/47092.pdf |
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| Chapelle, Annie; Le Gac, Mickael; Labry, Claire; Siano, Raffaele; Quere, Julien; Caradec, Florian; Le Bec, Claude; Nezan, Elisabeth; Doner, Anne; Gouriou, Jeremie. |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00278/38921/37461.pdf |
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| Guallar Morillo, Carlos; Chapelle, Annie; Bacher, Cedric. |
| En résumé, ce rapport présente les éléments suivants : 1. Identification et inventaire des données environnementales disponibles en relation avec l‟espèce A. minutum et Pseudo-nitzschia sur les côtes bretonnes et atlantiques françaises. 2. Description de la méthodologie développée pour l‟étude de la phénologie des efflorescences et la niche écologique des espèces cibles. 3. Présentation des résultats obtenus sur l‟étude de la phénologie d‟A. minutum. 4. Présentation des résultats obtenus sur l‟étude de la niche écologique d‟A. minutum et Pseudo-nitzschia. 5. Tableau de bord récapitulant les facteurs explicatifs, leur évolution et les risques associés en termes d‟efflorescences des espèces ciblées. |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00315/42640/42019.pdf |
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| Registros recuperados: 37 | |
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