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Registros recuperados: 35
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Assessment of eutrophication of French Mediterranean lagoons in relation to meteorological interannual variability ArchiMer
Malet, Nathalie; Derolez, Valerie; Laugier, Thierry; Munaron, Dominique; Fiandrino, Annie; Messiaen, Gregory; Fortune, Martine; Souchu, Philippe; Barral, Marc; Daloz, Aurélien; Moragues, Laurent.
Since recent decades, nutrient-related eutrophication, originating from agricultural use of fertilizer and population enhancement, can be considered worldwide as the main disturbance for coastal lagoons. Since coastal lagoons are very shallow and enclosed, their functioning is tightly linked to meteorological conditions. The aim of this study is to compare different rainfall levels and eutrophication response on coastal lagoons of the Languedoc-Roussillon (Western Mediterranean coast), subject to different nutrient loads from their watershed, in order to check the possibility to distinguish the effects of watershed management or rainfall conditions on water quality (waste water treatment plant improvement, decrease of fertilizer spreading).
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Ano: 2009 URL: http://archimer.ifremer.fr/doc/00008/11945/8651.pdf
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Bilan des observations hydrologiques du secteur côtier au large de la Loire et de la Vilaine en 2016 ArchiMer
Retho, Michael; Bizzozero, Lucie; Le Merrer, Yoann; Manach, Soazig; Collin, Karine; Fortune, Mireille; Schmitt, Anne; Gabellec, Raoul; Souchu, Philippe; Cochennec-laureau, Nathalie.
Ce rapport décrit le contexte hydrologique du littoral côtier du Morbihan, de la Loire Atlantique et de la Vendée Nord, sous l'influence des deux fleuves la Loire et la Vilaine, durant l'année 2016. Il s'appuie sur les suivis environnementaux réalisés dans le cadre des réseaux REPHY et DCE, complétés par les données acquises en haute fréquence sur la bouée MOLIT (réseau COAST HF-HOSEA).
Tipo: Text Palavras-chave: Hydrologie; DCE; Nutriment; Loire Bretagne; REPHY; Phytoplancton.
Ano: 2017 URL: http://archimer.ifremer.fr/doc/00416/52720/53593.pdf
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Bilan des observations hydrologiques du secteur côtier au large de la Loire et de la Vilaine en 2017 ArchiMer
Collin, Karine; Bizzozero, Lucie; Le Merrer, Yoann; Retho, Michael; Souchu, Philippe; Cochennec-laureau, Nathalie; Schapira, Mathilde; Manach, Soazig.
Ce rapport décrit le contexte hydrologique du littoral côtier du Morbihan, Pays de Loire et Nord Vendée, sous l’influence de la Loire et de la Vilaine, durant l’année 2017. Il s’appuie sur les suivis environnementaux réalisés dans le cadre des réseaux REPHY et de la DCE, complétés des données acquises en haute fréquence sur la bouée MOLIT (réseau COAST-HF).
Tipo: Text Palavras-chave: Hydrologie; DCE; Nutriment; Loire Bretagne; Rephy; Phytoplancton.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00472/58410/60972.pdf
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Biogeochemical aspects of bottom anoxia in a Mediterranean lagoon (Thau, France) ArchiMer
Souchu, Philippe; Gasc, Anne; Collos, Y; Vaquer, A; Tournier, Henri; Bibent, B; Deslous-paoli, Jean-marc.
Physical and chemical characteristics (temperature, salinity, dissolved oxygen), nutrients [dissolved inorganic nitrogen (DIN), soluble reactive phosphorus (SRP) and silicate], dissolved organic nitrogen (DON) and phosphorus and particulate matter [particulate organic carbon (POC) and nitrogen (PON) and chlorophyll a] were measured at a station located in the deepest part of the Thau lagoon (8.5 m), France, during a 10 d period of bottom anoxia in summer 1994. The upper 8 cm of sediment were also analyzed for ammonium (NH(4)(+)) and SRP concentrations in the porewater. The study period was characterized by mean wind speed under 4 m s(-1) which induced an increase of surface temperature from 18 to 29 degrees C with the formation of a thermocline. The...
Tipo: Text Palavras-chave: Anoxia; Nitrogen; Phosphorus; Eutrophication; Thau lagoon; Mediterranean Sea.
Ano: 1998 URL: http://archimer.ifremer.fr/doc/00070/18142/15694.pdf
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Caractérisation de l'état d'eutrophisation des trois principaux étangs corses (Biguglia, Diana et Urbino), et proposition de renforcement de leur surveillance. Rapport final ArchiMer
Orsoni, Valerie; Souchu, Philippe; Sauzade, Didier.
L'étude porte sur les trois principaux étangs corses (Biguglia, Diana et Urbino), situés à la bordure de la plaine orientale. Ecosystèmes fragiles et productifs, ces étangs supportent des enjeux importants, en tant qu'habitats naturels remarquables et du fait de leur exploitation intensive par la pêche, l'aquaculture et la conchyliculture. Cette étude vise à évaluer leur état d'eutrophisation, en utilisant une méthode de diagnostic spécifique aux milieux lagunaires méditerranéens, développée par l'Ifremer pour l'Agence de l'eau Rhône Méditerranée Corse, et portant sur l'utilisation d'indicateurs caractérisant la colonne d'eau, dont le phytoplancton, le sédiment et les macrophytes. Dans l'eau, les prélèvements ont été réalisés sur une période de 12 mois en...
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Ano: 2001 URL: http://archimer.ifremer.fr/doc/00074/18534/16078.pdf
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Comparing diatom and Alexandrium catenella/tamarense blooms in Thau lagoon: Importance of dissolved organic nitrogen in seasonally N-limited systems ArchiMer
Collos, Yves; Jauzein, Cecile; Ratmaya, Widya; Souchu, Philippe; Abadie, Eric; Vaquer, André.
Diatom blooms in Thau lagoon are always related to rain events leading to inputs of inorganic nutrients such as phosphate, ammonium and nitrate through the watershed with time lags of about 1 week. In contrast, blooms of Alexandrium catenella/tamarense can occur following periods of 3 weeks without precipitation and no significant input of conventional nutrients such as nitrate and phosphate. Field results also indicate a significant drop (from 22–25 to 15–16 μM over 3 days) in dissolved organic nitrogen (DON) at the bloom peak, as well as a significant inverse relationship between A. catenella/tamarense cell density and DON concentrations that is not apparent for diatom blooms. Such dinoflagellate blooms are also associated with elevated (6–9 μM) ammonium...
Tipo: Text Palavras-chave: Alexandrium catenella/tamarense; Non classical blooms; Organic nitrogen; Ammonium; Growth rate.
Ano: 2014 URL: http://archimer.ifremer.fr/doc/00194/30488/29758.pdf
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Contribution of several nitrogen sources to growth of Alexandrium catenella during blooms in Thau lagoon, southern France ArchiMer
Collos, Y; Vaquer, A; Laabir, M; Abadie, Eric; Laugier, Thierry; Pastoureaud, Annie; Souchu, Philippe.
A monitoring program with a weekly sampling frequency over a 15-month period indicates that urea concentrations above a certain threshold level may trigger the blooms of Alexandrium catenella in Thau lagoon. However, urea concentrations were also sometimes related to ammonium and dissolved organic nitrogen concentrations, indicating that the role of urea may not be a direct one. An original approach is used to assess the relative contribution of several nitrogen sources (nitrate, nitrite, ammonium, urea) to growth of A. catenella by comparing nitrogen uptake rates to nitrogen-based growth rates estimated from dilution experiments during four blooms over a 4-year period (2001-2004) in Thau lagoon. Nitrate and nitrite contributed 0.1-14% and 0.1-5%...
Tipo: Text Palavras-chave: Uptake kinetics; Ammonium; Urea; Growth; Nitrogen; HAB; Alexandrium catenella.
Ano: 2007 URL: http://archimer.ifremer.fr/doc/2007/publication-6454.pdf
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Diagnostic étendu de l'eutrophisation (DIETE). Rôle des sédiments dans le cycle des nutriments et impacts sur l'eutrophisation de la baie de Vilaine (2014-2017) ArchiMer
Souchu, Philippe; Cochennec-laureau, Nathalie; Ratmaya, Widya; Retho, Michael; Andrieux, Francoise; Le Merrer, Yoann; Barille, Laurent; Barille, Anne-laure; Goubert, Evelyne; Plus, Martin; Laverman, Anniet.
Le projet DIETE a exploré les données hydrobiologiques (paramètres physico-chimiques, nutriments, phytoplancton) acquises depuis les années 80 dans les eaux côtières au large de la Loire et de la Vilaine, parallèlement à celles des deux fleuves. L’augmentation des concentrations de nitrates dans les eaux de la Loire, appuyée par les réserves sédimentaires de phosphates et de silicate ont entraîné de profonds bouleversements dans la dynamique du phytoplancton de la baie de Vilaine ces deux dernières décennies avec 1) une augmentation substantielle de la biomasse, 2) une modification importante de l’évolution saisonnière, 3) un changement dans les proportions entre diatomées et dinoflagellés au profit des diatomées. Ces résultats ouvrent tout un champ...
Tipo: Text Palavras-chave: Eutophisation; Azote; Phosphore; Silicium; Sédiments; Modélisation.
Ano: 2018 URL: http://archimer.ifremer.fr/doc/00425/53695/54593.pdf
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Dinophag. Programme de recherche sur Dinophysis dans les eaux littorales des Pays de la Loire ArchiMer
Souchu, Philippe; Oger-jeanneret, Helene; Lassus, Patrick; Sechet, Veronique; Le Magueresse, Alain; Le Bihan, Veronique.
Ce document résume les conclusions du programme de recherche Dinophag réalisé par l’Ifremer avec l’aide de la Région Pays de la Loire de janvier 2011 à décembre 2012. Il est destiné à tous ceux qui se sont interrogés sur la place que tient la microalgue toxique Dinophysis dans l’économie littorale de notre Région. Les lecteurs y découvriront aussi que Dinophysis n’est pas vraiment une microalgue comme les autres et qu’il reste encore pour les chercheurs de nombreuses interrogations sur le déterminisme de son développement et de sa toxicité.
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Ano: 2013 URL: http://archimer.ifremer.fr/doc/00172/28368/26660.pdf
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Distribution of picophytoplankton and nanophytoplankton along an anthropogenic eutrophication gradient in French Mediterranean coastal lagoons ArchiMer
Bec, Beatrice; Collos, Yves; Souchu, Philippe; Vaquer, Andre; Lautier, Jacques; Fiandrino, Annie; Benau, Laurent; Orsoni, Valerie; Laugier, Thierry.
We explored the role of natural and anthropogenic environmental perturbations in shaping the community structure and dynamics of pico- and nanophytoplankton in coastal waters. The distribution patterns of phycoerythrin-rich picocyanobacteria (PE-CYAN) and phycocyanin-rich picocyanobacteria (PC-CYAN), autotrophic picoeukaryotes (PEUK) and nanophytoplankton (NANO) were examined over a period of 3 yr in 24 Mediterranean coastal lagoons displaying wide trophic gradients (from 0.2 to 630 mu g chlorophyll a [chl a] l(-1)) and salinity gradients (from fresh to marine waters). In summer, picoplanktonic abundances reached 3 x 10(8) cells l(-1), 5 x 10(9) cells l(-1) and 6 x 10(10) cells l(-1) for PE-CYAN, PC-CYAN and PEUK, respectively. PE-CYAN and PC-CYAN showed...
Tipo: Text Palavras-chave: Autotrophic picoeukaryotes; Picocyanobacteria; Nanophytoplankton; Abundance; Biomass; Eutrophication; Mediterranean lagoons.
Ano: 2011 URL: http://archimer.ifremer.fr/doc/00031/14267/11547.pdf
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Dynamique hivernale des nutriments et du carbone dans les cours d’eau contrastés du Marais poitevin et flux terrestres associés en Baie de l’Aiguillon ArchiMer
Polsenaere, Pierre; Le Marchand, Marie; Le Moine, Olivier; Soletchnik, Patrick; Chabirand, Jean-michel; Geairon, Philippe; Thomas, Gerard; Bechemin, Christian; Souchu, Philippe; Joyeux, Emmanuel; Le Roy, Yoann; Corre, Frédéric.
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Ano: 2017 URL: http://archimer.ifremer.fr/doc/00405/51629/52184.pdf
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Ecologie conchylicole : de l'exploitation à l'environnement ArchiMer
Deslous Paoli, Jean-marc; Souchu, Philippe.
Tipo: Text
Ano: 1993 URL: http://archimer.ifremer.fr/doc/00083/19472/17087.pdf
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Eutrophication: A new wine in an old bottle? ArchiMer
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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Influence of nitrogen enrichment on size-fractionated in vitro carboxylase activities of phytoplankton from Thau Lagoon (Coastal Mediterranean Lagoon, France) ArchiMer
Fouilland, Eric; Descolas Gros, Chantal; Collos, Yves; Vaquer A, André; Souchu, Philippe; Gasc, Anne; Bibent, Bertrand; Pons, Virginie.
The influence of dissolved inorganic and organic nitrogen (DIN and DON) enrichments on pools of enzymes responsible for CO2 fixation by the Calvin-Benson (Rubisco) and beta-carboxylation pathways (beta-carboxylases) were studied in a natural plankton assemblage. The plankton community from a coastal Mediterranean lagoon were incubated in situ for 24 h with initially ammonium, nitrate and DON (taurine) enrichments and compared to a control without any enrichment. An increase of small picophytoplankton and diatom biomass was observed in the enriched inorganic nitrogen treatments 7 - 10 h after the initial enrichment. Phytoplankton biomass decreased in the control and under taurine enrichment suggesting an inorganic nitrogen limitation of phytoplankton growth.
Tipo: Text Palavras-chave: Heterotrophy; Autotrophy; Nitrogen enrichments; Size fractionated phytoplankton; Carboxylase activities.
Ano: 2002 URL: http://archimer.ifremer.fr/doc/2002/publication-451.pdf
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Influence of shellfish farming activities on nitrification, nitrate reduction to ammonium and denitrification at the water-sediment interface of the Thau lagoon, France ArchiMer
Gilbert, F; Souchu, Philippe; Bianchi, M; Bonin, P.
The seasonal patterns of nitrification, denitrification and dissimilatory ammonium production (DAP) rates were studied in the sediment of 2 stations in the Thau lagoon (south of France). The station ZA was located within the shellfish farming zone and the station B was the reference site. A marked effect of shellfish fanning on bacterial activities was observed. Spatial differences were associated with discrepancies in the organic content and the reduction state of sediments, i.e. highest reductive processes (denitrification and DAP) were noted in shellfish farming area, whereas the oxidative process (nitrification) was predominant outside the farming zone. At both stations, the DAP activity increased in September (autumn) concomitant with an increase of...
Tipo: Text Palavras-chave: Shellfish farming; Nitrogen bacterial processes; Nitrification; Nitrate reduction to ammonium; Denitrification; Thau lagoon; Mediterranean Sea; Sediment-water exchanges.
Ano: 1997 URL: http://archimer.ifremer.fr/doc/00070/18145/15697.pdf
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Influence of shellfish farming activities on the biogeochemical composition of the water column in Thau lagoon ArchiMer
Souchu, Philippe; Vaquer A, André; Collos, Yves; Landrein, Sonia; Deslous-paoli, Jean-marc; Bibent, Bertrand.
Thau lagoon is a Mediterranean shellfish ecosystem with large biomasses of oysters growing in waters with high residence time due to low tidal ranges, The influence of filter feeders (oysters and their epibiota) on the spatial distribution of particulate and dissolved compounds in the water column of Thau lagoon was studied through its variation with time, In 1991/1992, daily variations were investigated in pens, corridors and outside shellfish farming zones for nutrients, chlorophyll a and primary production. Salinity, dissolved oxygen, nutrients, organic matter and chlorophyll a were also monitored in surface waters inside and outside shellfish farming zones each week from January 1993 to March 1994. The presence of shellfish farms led to a decrease by...
Tipo: Text Palavras-chave: Thau lagoon; Carrying capacity; Nutrient cycling; Phytoplankton; Suspension feeding bivalves.
Ano: 2001 URL: http://archimer.ifremer.fr/doc/2001/publication-808.pdf
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La crise anoxique du bassin de Thau de l'été 1997. Bilan du phénomène et perspectives ArchiMer
Souchu, Philippe; Abadie, Eric; Vercelli, Catherine; Buestel, Dominique; Sauvagnargues, Jean-claude.
La crise anoxique ou «malaïgue» qui a sévi dans le bassin de Thau durant l'été 1997 a détruit presque le tiers de la production annuelle d'huîtres. Son déclenchement a suivi une période durant laquelle les vents étaient exceptionnellement faibles. Après un rappel scientifique des processus mis en jeu, la crise anoxique est décrite au travers des observations de mortalités et des concentrations en oxygène dissous. Les eaux anoxiques se sont développées dans les zones conchylicoles vers l'Est et l'Ouest à partir d'un foyer situé à proximité du principal port conchylicole (Mourre-Blanc à Mèze). La comparaison de la crise de 1997 avec celles qui l'ont précédée fait apparaître un recul de l'eutrophisation depuis 25 ans. En revanche, des secteurs très localisés...
Tipo: Text Palavras-chave: Lagunes; Thau; Conchyliculture; Anoxies; Eutrophisation; Crassostrea gigas.
Ano: 1998 URL: http://archimer.ifremer.fr/doc/00039/15010/12336.pdf
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Le Continuum Homme-Terre-Mer ArchiMer
Garnier, Josette; Castelle, Bruno; Labille, Jérôme; Souchu, Philippe; Thieu, Vincent; Delacourt, Christophe.
L’interface entre l’atmosphère et les surfaces continentales est un lieu d’échanges importants d’énergie et de matière liquide, solide ou gazeuse. Aussi, comprendre et quantifier les interactions entre surfaces et atmosphère est un enjeu de premier ordre pour essayer d’anticiper au mieux les conséquences de nouvelles et futures évolutions des surfaces continentales, que ce soit sous l’effet de l’évolution du climat ou de modifications de l’usage des sols. Des processus spécifiques se produisent à l’interface surface-atmosphère, rendant nécessaire l’étude de cette interface non comme un simple lieu de transfert, mais en tant qu’objet propre. S’attacher à identifier et quantifier les processus opérant dans le continuum sol-eau-plante-atmosphère doit...
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Ano: 2019 URL: https://archimer.ifremer.fr/doc/00603/71464/69919.pdf
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L'eutrophisation des eaux marines et saumâtres en Europe, en particulier en France ArchiMer
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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L’eutrophisation : manifestations, causes, conséquences et prédictibilité. Synthèse de l’Expertise scientifique collective CNRS - Ifremer - INRA - Irstea ArchiMer
Pinay, Gilles; Gascuel, Chantal; Menesguen, Alain; Souchon, Yves; Le Moal, Morgane; Levain, Alix; Moatar, Florentina; Pannard, Alexandrine; Souchu, Philippe.
L'eutrophisation génère des perturbations majeures pour les écosystèmes aquatiques et a des impacts sur les biens et les services associés, sur la santé humaine et sur les activités économiques. Ses manifestations les plus connues sont les efflorescences de cyanobactéries toxiques dans les lacs et cours d'eau et les proliférations de macroalgues vertes dans les zones côtières. Ces proliférations représentent de fortes biomasses dont la décomposition par des bactéries induit un appauvrissement ou un épuisement en oxygène du milieu, voire l'émission de gaz toxiques. Les débats sur l'identification des facteurs et des niveaux de risque d'eutrophisation ont conduit à la réalisation d'une expertise scientifique collective. Elle vise à fournir aux pouvoirs...
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Ano: 2017 URL: http://archimer.ifremer.fr/doc/00408/51903/52526.pdf
Registros recuperados: 35
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