Consulta: creatorFacets:"Chapelle, Annie"
Registros recuperados: 37
Data/hora: 03/06/2024 07:34:27

Modelling seasonal dynamics of biomasses and nitrogen contents in a seagrass meadow (Zostera noltii Hornem.): application to the Thau lagoon (French Mediterranean coast)
Provedor de dados: 5
Autores: 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

Resource Competition Affects Plankton Community Structure; Evidence from Trait-Based Modeling
Provedor de dados: 5
Autores: Sourisseau, Marc; Le Guennec, Valerie; Le Gland, Guillaume; Plus, Martin; Chapelle, Annie.
Understanding the phenology of phytoplankton species is still a challenge and despite a lot of theoretical work on competition for ressources this process is under-represented in deterministic models. To study the main driver of the species selection, we thus used a trait-based model that keeps phenotypic variability through physiological trait parameterization. We next validate the results by using a key species, the toxic dinoflagellate Alexandrium minutum. Due to their monitoring, we show that harmful algae are ideal models for studying ecological niches and for contributing to this more global challenge. As a first step, a dimensionless model of an estuary (France) was built with water temperature and water exchanges deduced from a hydro-dynamic model....
Tipo: Text
Palavras-chave: Droop; Competition; Inter-specific; Estuary; Bay of Brest; Alexandrium minutum; Phenology; Niches.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00373/48414/48624.pdf

Modelling nitrogen, primary production and oxygen in a Mediterranean lagoon. Impact of oysters farming and inputs from the watershed
Provedor de dados: 5
Autores: 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

DYNAPSE - DYNamiques des efflorescences et de la toxicité des espèces phytoplanctoniques nuisibles du genre PSEudo nitzschia en région Loire Bretagne
Provedor de dados: 5
Autores: Belin, Catherine; Chapelle, Annie; Delmas, Daniel; Nezan, Elisabeth; Siano, Raffaele.
Les efflorescences de la diatomée Pseudo-nitzschia sont largement répandues sur les côtes Manche-Atlantique depuis une trentaine d’années (source Rephy). Depuis les années 2000 elles y sont parfois associées des événements toxiques du type ASP (Amnesic Shellfish Poisonning) qui perturbent grandement les pêcheries de coquillages et notamment celles de coquilles Saint Jacques. Les efflorescences et toxicités liées aux Pseudo-nitzschia sont des phénomènes en augmentation sur les côtes françaises mais aussi mondialement. Le genre Pseudo-nitzschia comprend plusieurs espèces très difficiles à identifier en routine or certaines sont toxiques et d’autres pas. Les facteurs environnementaux abiotiques et biotiques contrôlent à la fois la croissance des microalgues...
Tipo: Text
Palavras-chave: Algues toxiques; Pseudo nitzschia; Toxicité des coquillages; Pêcheries; Facteurs environnementaux.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00189/30035/28521.pdf

Étude sur la prolifération de la micro algue Alexandrium minutum en rade de Brest. Projet Daoulex. Rapport d’avancement n° 2 : Analyse des traces biologiques d’Alexandrium minutum dans les sédiments de la Rade de Brest.
Provedor de dados: 5
Autores: 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
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00191/30231/28647.pdf

Modélisation écologique de la Baie de la Vilaine - Rapport annuel
Provedor de dados: 5
Autores: 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
Ano: 1989
URL: http://archimer.ifremer.fr/doc/00104/21526/19107.pdf

Analysis of hydrobiological pattern in the Bizerte lagoon (Tunisia)
Provedor de dados: 5
Autores: 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

Competition for phosphorus between two dinoflagellates: A toxic Alexandrium minutum and a non-toxic Heterocapsa triquetra
Provedor de dados: 5
Autores: 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

PHENOMER: Better knowledge of HAB with the help of citizen observations
Provedor de dados: 5
Autores: Curd, Amelia; Chapelle, Annie; Siano, Raffaele.
Tipo: Text
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00213/32415/30888.pdf

Global and local factors driving the phenology of Alexandrium minutum (Halim) blooms and its toxicity
Provedor de dados: 5
Autores: 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

Etude écophysiologique et paramétrisation du rôle du phosphore sur la croissance d'Alexandrium minutum, espèce responsable d'eaux colorées toxiques en estuaire de Penzé, et de son principal compétiteur Heterocapsa triquetra - Rapport final PNEC-ART3
Provedor de dados: 5
Autores: 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
Ano: 2004
URL: http://archimer.ifremer.fr/doc/00105/21598/19178.pdf

L'eutrophisation des eaux marines et saumâtres en Europe, en particulier en France
Provedor de dados: 5
Autores: 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

Phenomer. Rapport d’activités de juillet 2015 à septembre 2016 pour la Fondation de France
Provedor de dados: 5
Autores: Curd, Amelia; Siano, Raffaele; Chapelle, Annie; Pilven, Sophie.
Tipo: Text
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00356/46694/46556.pdf

Comprendre, Prédire et Agir sur les efflorescences toxiques. Jusqu'où peut-on aller aujourd'hui dans le cas d'Alexandrium minutum en Penzé ?
Provedor de dados: 5
Autores: Chapelle, Annie; Andrieux, Francoise; Fauchot, Juliette; Guillaud, Jean-francois; Labry, Claire; Sourisseau, Marc; Verney, Romaric.
Tipo: Text
Ano: 2007
URL: http://archimer.ifremer.fr/doc/00105/21651/19232.pdf

Modélisation des cycles de l'azote et du phosphore dans les sédiments d'une lagune soumise à une exploitation conchylicole
Provedor de dados: 5
Autores: 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

Modélisation du phytoplancton dans les écosystèmes côtiers. Application à l’eutrophisation et aux proliférations d’algues toxiques
Provedor de dados: 5
Autores: 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
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00360/47141/47092.pdf

Rapid detection and quantification of the marine toxic algae, Alexandrium minutum, using a super-paramagnetic immunochromatographic strip test
Provedor de dados: 5
Autores: Gas, Fabienne; Baus, Beatrice; Quere, Julien; Chapelle, Annie; Dreanno, Catherine.
The dinoflagellates of Alexandrium genus are known to be producers of paralytic shellfish toxins that regularly impact the shellfish aquaculture industry and fisheries. Accurate detection of Alexandrium including A. minutum is crucial for environmental monitoring and sanitary issues. In this study, we firstly developed a quantitative lateral flow immunoassay (LFIA) using super-paramagnetic nanobeads for A. minutum whole cells. This dipstick assay relies on two distinct monoclonal antibodies used in a sandwich format and directed against surface antigens of this organism. No sample preparation is required. Either frozen or live cells can be detected and quantified. The specificity and sensitivity are assessed by using phytoplankton culture and field samples...
Tipo: Text
Palavras-chave: Alexandrium minutum; Detection; Quantification; Dipstick lateral flow immunoassay; Super-paramagnetic.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00286/39695/38152.pdf

The Bay of Brest (France), a new risky site for toxic Alexandrium minutum blooms and PSP shellfish contamination
Provedor de dados: 5
Autores: Chapelle, Annie; Le Gac, Mickael; Labry, Claire; Siano, Raffaele; Quere, Julien; Caradec, Florian; Le Bec, Claude; Nezan, Elisabeth; Doner, Anne; Gouriou, Jeremie.
Tipo: Text
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00278/38921/37461.pdf

Effet des changements environnementaux sur les communautés phytoplanctoniques et évaluation des risques d’efflorescences d’algues toxiques (PhytoRisk)
Provedor de dados: 5
Autores: 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
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00315/42640/42019.pdf

Effet des changements environnementaux sur les communautés phytoplanctoniques et évaluation des risques d’efflorescences d’algues toxiques (PhytoRisk). Livrable : Données environnementales utilisées et modèles de la phénologie des espèces de phytoplancton
Provedor de dados: 5
Autores: Guallar Morillo, Carlos; Chapelle, Annie; Bacher, Cedric.
Ce rapport d'étape présente les éléments suivants :  1. Identification et inventaire des données environnementales disponibles en relation avec l’espèce A. minutum sur les côtes bretonnes et atlantiques françaises. 2. Description de la méthodologie développée pour l’étude de la phénologie des efflorescences d’A. minutum. 3. Présentation des premiers résultats obtenus sur l’étude de la phénologie.
Tipo: Text
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00278/38878/37417.pdf

Two decades of Pseudo-nitzschia spp. blooms and king scallop (Pecten maximus) contamination by domoic acid along the French Atlantic and English Channel coasts: Seasonal dynamics, spatial heterogeneity and interannual variability
Provedor de dados: 5
Autores: Husson, Berengere; Hernandez Farinas, Tania; Le Gendre, Romain; Schapira, Mathilde; Chapelle, Annie.
King scallop contamination (Pecten maximus) by domoic acid, a neurotoxin produced by some species of the diatom Pseudo-nitzschia, is highly problematic because of its lengthy retention in the bivalve tissue, leading to prolonged fishery closures. Data collected within the French Phytoplankton and Phycotoxin monitoring network (REPHY) over the 1995–2012 period were used to characterize the seasonal dynamics and the interannual variability of P.-nitzschia spp. blooms as well as the contamination of king scallop fishing grounds, in six contrasted bays distributed along the French Atlantic coast and English Channel. Monitoring revealed that these toxic events have become more frequent since the year 2000, but with varying magnitudes, frequencies and timing...
Tipo: Text
Palavras-chave: Pseudo-nitzschia spp.; Domoic acid; King scallop; Interannual variability; Seasonal dynamics; Environmental parameters.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00299/40983/40084.pdf

Contribution of climate variability to occurrences of anoxic crises 'malaigues' in the Thau lagoon (southern France)
Provedor de dados: 5
Autores: Harzallah, Ali; Chapelle, Annie.
The Thau lagoon, located in southern France, suffers episodically in summer from anoxic crises known as 'malaigues'. Such crises mostly occur under warm conditions and low winds. In this paper we investigated effects of local weather conditions (air temperature, wind speed and precipitation over southern France), and two climate oscillations (the North Atlantic Oscillation and the El Ni (n) over tildeo Oscillation) on malaigue occurrences based on 33-year data series and dates when malaigues appeared. The study shows that the probability of occurrence of malaigues increases with increasing temperature and decreasing winds in August both mostly associated to the high phase of an index of North Atlantic Oscillation. Malaigues are found to be frequently...
Tipo: Text
Palavras-chave: Lagoon; Thau; Malaigues; Anoxic crises; Climate variability; Lagune; Thau; Malaïgue; Eutrophisation; Variabilité climatique.
Ano: 2002
URL: http://archimer.ifremer.fr/doc/2002/publication-517.pdf

Modelling water discharges and nitrogen inputs into a Mediterranean lagoon - Impact on the primary production
Provedor de dados: 5
Autores: Plus, Martin; La Jeunesse, I; Bouraoui, F; Zaldivar, J; Chapelle, Annie; Lazure, Pascal.
The Soil and Water Assessment Tool (SWAT model, 2001 Version) has been applied to the Than lagoon catchment area in order to simulate water discharges and nutrient inputs into the lagoon over a 10 years period (1989-1999), and to provide routing inflows to a previously developed lagoon ecosystem model. The watershed model has been calibrated and validated using measured data available for the two main rivers. The results indicate that the mean annual nitrogen inputs into the Thau lagoon is 117 +/- 57 tons y(-1), with the two main rivers, contributing for 80% of total annual nitrogen export. The variations of outputs to the lagoon are nonetheless important from 1 year to another. Due to the local agricultural practices and a reduced in-stream natural...
Tipo: Text
Palavras-chave: Thau lagoon; Primary production; Integrated modelling; Lagoon model; Watershed model.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/publication-1118.pdf

Etude sur la prolifération de la micro algue Alexandrium minutum en rade de Brest. Projet Daoulex. Rapport d’avancement n° 1 : Novembre 2013
Provedor de dados: 5
Autores: Chapelle, Annie; Le Bec, Claude; Le Gac, Mickael; Labry, Claire; Amzil, Zouher; Guillou, Laure; Dreanno, Catherine; Pineau-guillou, Lucia.
Suite à l’événement de grande ampleur d’efflorescence d’Alexandrium minutum et des toxicités associées en Rade de Brest en 2012, un projet a été monté avec la Région dans le cadre du développement du port de Brest. De juillet à août 2013, l’Ifremer a organisé un échantillonnage serré dans l’estuaire de Daoulas, zone la plus touchée en 2012. De ce suivi et des mesures réalisées au laboratoire à ce jour, ainsi que des résultats du réseau Rephy et Velyger, il ressort que : * Alexandrium minutum s’est développé à nouveau en rade de Brest en 2013 mais à des teneurs inférieures à 2012. * l’épisode de bloom et de toxicité supérieur aux seuils légaux s’est déroulé plus tard qu’en 2012, du 1er juillet jusqu’à 5 août. * les efflorescences et la toxicité ont touché...
Tipo: Text
Ano: 2013
URL: https://archimer.ifremer.fr/doc/00191/30230/28644.pdf

Phenomer. Rapport d’activités de juillet 2014 à juin 2015 pour la Fondation de France
Provedor de dados: 5
Autores: Curd, Amelia; Antoine, Virginie; Chapelle, Annie; Siano, Raffaele; Pilven, Sophie.
Tipo: Text
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00286/39762/38255.pdf

Modelling the impact of a cultivated oyster population on the nitrogen dynamics: the Thau lagoon case (France)
Provedor de dados: 5
Autores: Bacher, Cedric; Bioteau, Hélène; Chapelle, Annie.
The Thau lagoon (France) is an important site for the cultivation of Crassastrea gigas. The relationship belween the oyster population and the environment was assessed through a model of trophic relationships. The results represent the initial step lowards a more precise assessment of the biological fluxes in the lagoon. This preliminary model was based on the nitrogen dynamics among the following compartments: phytoplankton, zooplankton. oysters. detritus and dissolved inorganic nitrogen in the water column. Two other compartments were also considered in the sediment: detritus and dissolved nitrogen. The model considered the watershed input and seawater exchange belween the lagoon and the open sea . The parameters were estimated from experiments on oyster...
Tipo: Text
Palavras-chave: Oyster; Crassostrea gigas; Nitrogen dynamics; Impact.
Ano: 1995
URL: http://archimer.ifremer.fr/doc/00039/15069/12403.pdf

Influence of gametogenesis pattern and sex on paralytic shellfish toxin levels in triploid Pacific oyster Crassostrea gigas exposed to a natural bloom of Alexandrium minutum
Provedor de dados: 5
Autores: Hermabessiere, Ludovic; Fabioux, C.; Lassudrie, Malwenn; Boullot, F.; Long, Marc; Lambert, Christophe; Le Goic, N.; Gouriou, Jeremie; Le Gac, Mickael; Chapelle, Annie; Soudant, P.; Hegaret, Helene.
This study investigated the effect of gametogenesis pattern and sex on levels of paralytic shellfish toxins (PST) accumulated by triploid oysters Crassostrea gigas exposed to a natural bloom of the toxic dinoflagellate Alexandrium minutum in the Bay of Brest (Western Brittany, France), over the summer 2014. Toxin accumulation in oysters was proposed to be influenced by the proportion of energy allocated to reproduction versus other metabolisms, as proposed by Haberkorn et al. (2010). Thus, we hypothesized that triploid oysters with different gametogenesis patterns (α or β, producing respectively numerous gametes or rare gametes) could result in differences in toxin accumulation. Toxin level could also be different according to the gender of the oysters. To...
Tipo: Text
Palavras-chave: Crassostrea gigas; Alexandrium minutum; Harmful algal bloom (HAB); Paralytic shellfish toxin (PST); Gametogenesis pattern; Triploid.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00307/41801/41010.pdf

Modélisation d'un écosysteme marin côtier soumis a l'eutrophisation : la baie de vilaine (sud bretagne). Etude du phytoplancton et du bilan en oxygène
Provedor de dados: 5
Autores: Chapelle, Annie.
The Bay of Vilaine (South-Brittany, France ) has been affected for many years by eutrophication process . Discoloured waters, oxygen depletion in bottom waters occured, being sometimes so drastic as in July 1982 that several ten tons of fishes and invertebrates were killed by anoxia. This coastal ecosystem is studied using a box model simulating the nitrogen cycle, oxygen and salinity. The model takes into account river inputs and exchanges with the ocean. It is calibrated and validated against several year measurements. The understanding of primary production and oxygen budget is improved. Phosphorus cycle simulation is then added in the model. The impact of different reductions of river nutrients on chlorophyll concentration and on hypoxia in the Bay are...
Tipo: Text
Ano: 1991
URL: http://archimer.ifremer.fr/doc/00015/12611/9490.pdf

Evolutionary processes and cellular functions underlying divergence in Alexandrium minutum
Provedor de dados: 5
Autores: Le Gac, Mickael; Metegnier, Gabriel; Chomerat, Nicolas; Malestroit, Pascale; Quere, Julien; Bouchez, Olivier; Siano, Raffaele; Destombe, Christophe; Guillou, Laure; Chapelle, Annie.
Understanding divergence in the highly dispersive and seemingly homogeneous pelagic environment for organisms living as free drifters in the water column remains a challenge. Here, we analyzed the transcriptome wide mRNA sequences, as well as the morphology of 18 strains of Alexandrium minutum, a dinoflagellate responsible for Harmful Algal Blooms worldwide, to investigate the functional bases of a divergence event. Analysis of the joint site frequency spectrum (JSFS) pointed toward an ancestral divergence in complete isolations followed by a secondary contact resulting in gene flow between the two diverging groups, but heterogeneous across sites. The sites displaying fixed SNPs were associated with a highly restricted gene flow and a strong...
Tipo: Text
Palavras-chave: Dinoflagellates; Harmful algal blooms; Populations Genomics; Pseudocryptic species; Speciation.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00347/45857/45529.pdf

MODELLING REPORT. Coastal lagoon modelling : An integrated approach. Deliverables D12 – D13 – D14
Provedor de dados: 5
Autores: Chapelle, Annie; Bacher, Cedric; Duarte, P; Fiandrino, Annie; Galbiati, L; Marinov, D; Martinez, J; Norro, A; Pereira, A; Plus, Martin; Rodriguez, S; Tsirtsis, G; Zaldivar, Jm.
Tipo: Text
Ano: 2005
URL: http://archimer.ifremer.fr/doc/00348/45930/45622.pdf

Harmful algae niche responses to environmental and community variation along the French coast
Provedor de dados: 5
Autores: Karasiewicz, Stephane; Chapelle, Annie; Bacher, Cedric; Soudant, Dominique.
Distribution, frequency and intensity of harmful phytoplanktonic species are impacted by changes in environmental conditions. In the Bay of Brest, Alexandrium minutum has been responsible for several harmful algal blooms (HABs) associated with toxin production causing paralytic shellfish poisoning (PSP). Additionally, Lepidodinium chlorophorum causes green water and hypoxia locally in the Bay of Biscay. Previous studies revealed that L. chlorophorum’s success was related to possible competitive exclusion. Therefore, the phytoplankton composition and the environmental conditions should be taken into account. This study aims to assess the combined effect of changes in habitat conditions and community structure with the occurrence of HAB species, on a...
Tipo: Text
Palavras-chave: Alexandrium minutum; Lepidodinium chlorophorum; Subniche; Competition; Indicating species; Spatio-temporal data.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00614/72567/71521.xml

Modélisation de l'eutrophisation de la Baie de Vilaine et des phénomènes d'anoxie associés
Provedor de dados: 5
Autores: Chapelle, Annie.
The Vilaine bay (South Brittany) has been showing for many years eutrophication troubles (red tides, anoxia, toxic blooms...). Facing these biological and economical problems, scientific studies have been performed and the results are joined in an ecological box model of the bay. It simulates the primary production through nitrogen cycle, dissolved oxygen, and salinity, used to calibrate the advection-dispersion fluxes of the physical submodel. The model is running several years to bring out the seasonal characteristics of this site. A special attention is reported on the oxygen balance sheet. Simulations try to quantify the oxygen demand and to recognize the major cause of anoxia. These results are applied to reproduce the July 1982 anoxia, which caused...
Tipo: Text
Ano: 1990
URL: https://archimer.ifremer.fr/doc/00480/59124/61752.pdf

Modèle des cycles de l'azote et du phosphore à l'interface eau-sédiment. Application à l'étang de Thau
Provedor de dados: 5
Autores: Chapelle, Annie.
Le programme de recherche Oxythau a pour but l'étude des relations concyliculture - milieu dans l'étang de Thau. Dans ce contexte, l'interface eau-sédiment apparait comme une structure majeure intervenant dans les cycles de la matière et dans les problèmes de dysfonctionnement de l'écosystème (malaïgues). Un modèle en azote et en phosphore simule les étapes de transformation de la matière organique sédimentée jusqu'au relargage de sels nutritifs, ainsi que la concentration en oxygène qui intervient dans les cinétiques de dégradation. L'ensemble de ces réactions est simulé au moyen d'un modèle vertical. La colonne d'eau est scindée en cinq boîtes de 1m superposées et le sédiment en deux boîtes de 5 cm. Ce modèle est mis au point en situation d'équilibre...
Tipo: Text
Ano: 1993
URL: http://archimer.ifremer.fr/doc/00060/17091/14604.pdf

Alexandrium minutum growth controlled by phosphorus An applied model
Provedor de dados: 5
Autores: Chapelle, Annie; Labry, Claire; Sourisseau, Marc; Lebreton, Carole; Youenou, Agnes; Crassous, Marie-pierre.
Toxic algae are a worldwide problem threatening aquaculture public health and tourism Alexandrium a toxic dinoflagellate proliferates in Northwest France estuaries (i e the Penze estuary) causing Paralytic Shellfish Poisoning events Vegetative growth and in particular the role of nutrient uptake and growth rate are crucial parameters to understand toxic blooms With the goal of modelling in situ Alexandrium blooms related to environmental parameters we first try to calibrate a zero-dimensional box model of Alexandrium growth This work focuses on phosphorus nutrition Our objective is to calibrate Alexandrium minutum as well as Heterocapsa triquetra (a non-toxic dinoflagellate) growth under different rates of phosphorus supply other factors being optimal and...
Tipo: Text
Palavras-chave: Toxic algal blooms; Alexandrium; Phosphorus uptake; Models; Competition; Northwest France.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00018/12901/9905.pdf

Étude sur la prolifération de la micro algue Alexandrium minutum en rade de Brest
Provedor de dados: 5
Autores: Chapelle, Annie; Le Bec, Claude; Amzil, Zouher; Dreanno, Catherine; Guillou, Laure; Klouch, Khadidja; Labry, Claire; Le Gac, Mickael; Pineau-guillou, Lucia; Siano, Raffaele; Abernot, Chantal; Andrieux, Francoise; Caradec, Florian; Destombe, Christophe; Dia, A.; Doner, Anne; Duval, Julia; Gouriou, Jeremie; Lazure, Pascal; Le Brun, Luc; Le Gal, Dominique; Malestroit, Pascale; Petton, Sebastien; Plus, Martin; Quere, Julien; Savar, Veronique; Schmitt, Sophie; Terre, A.; Youenou, Agnes.
Suite à l’événement de grande ampleur d’efflorescence d’Alexandrium minutum et des toxicités associées en Rade de Brest en 2012, un projet a été élaboré avec la Région Bretagne dans le cadre du développement du port de Brest. L’Ifremer a organisé un échantillonnage dans l’estuaire de la rivière de Daoulas, zone la plus touchée en 2012, au cours des printemps-été 2013 et 2014. Un suivi de la présence d’A. minutum dans les sédiments a également été réalisé en hiver 2014. De ces suivis, des mesures réalisées au laboratoire à ce jour, des simulations du modèle Prévimer ainsi que des résultats du réseau Rephy et Velyger, il ressort que: * La rade de Brest peut aujourd’hui être considérée comme une zone à risque pour Alexandrium minutum. En effet, depuis 2012...
Tipo: Text
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00254/36487/35029.pdf

Phenomer. Rapport d'Etude pour l'Agence de l'Eau Loire-Bretagne
Provedor de dados: 5
Autores: Curd, Amelia; Antoine, Virginie; Chapelle, Annie; Siano, Raffaele; Pilven, Sophie.
Tipo: Text
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00286/39760/38253.pdf

Modelling of oxygen and nitrogen cycling as a function of macrophyte community in the Thau lagoon
Provedor de dados: 5
Autores: Plus, Martin; Chapelle, Annie; Lazure, Pascal; Auby, Isabelle; Levavasseur, G; Verlaque, M; Belsher, Thomas; Deslous-paoli, Jean-marc; Zaldivar, J; Murray, C.
A three-dimensional model coupling physical and biological processes for the whole Than lagoon (Mediterranean coast of France) was developed in order to assess the relationships between macrophytes and the oxygen and nitrogen cycles. Ten species have been inserted as forcing variables in the model. Plankton dynamics, shellfish cultivation impact and mineralization of organic matter are also considered, as well as nutrient and oxygen exchanges between the sediment and the water column.   Simulations with and without the macrophytes have shown that the system can be characterized as having a highly structured pattern involving lagoon nitrogen and oxygen cycles. This pattern is created by the combined influence of macrophytes, watershed and oyster farming....
Tipo: Text
Palavras-chave: Thau lagoon; Biogeochemical cycles; Ecological modelling; Macrophytes.
Ano: 2003
URL: https://archimer.ifremer.fr/doc/2003/publication-459.pdf