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| Registros recuperados: 26 | |
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| Vincendeau, Marie-laure. |
| L'impact de l'excrétion de Mollusques Bivalves cultivés sur la croissance de Diatomées dans les zones conchylicoles est étudié expérimentalement. Les Huîtres et les Palourdes enrichissent les eaux où elles séjournent en ammoniaque, urée, acides aminés et autres substances azotées ainsi qu'en phosphore minéral et organique dissous. En conséquence, la fertilité potentielle des eaux pour trois Diatomées des milieux conchylicoles est améliorée. De plus, les algues bénéficient parfois d'apports complémentaires de vitamines et de métaux de la part des Mollusques. Les Diatomées prélèvent les nitrates simultanément à l'ammoniaque. Elles peuvent de plus utiliser l'azote organique dissouss sous les formes excrétées par les Bivalves. Parmi ces formes, la taurine peut... |
| Tipo: Text |
Palavras-chave: Mollusques bivalves; Excrétion; Diatomées; Azote; Phosphore; Taurine; Essais biologiques; Indice de fertilité. |
| Ano: 1987 |
URL: http://archimer.ifremer.fr/doc/00443/55477/57007.pdf |
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| Piriou, Jean-yves; Coic, Daniel; Merceron, Michel. |
| The coastal marsh of Kervigen is located near by the bay of Douarnenez and its 22 hectares are almost entirely covered by reeds. An experiment was there carried out to assess the nitrogen flux depletion of a small stream, the Kerharo. That one has a 45 km 2 mostly agricultural drainage basin. Due to its nitrate loadings to the next sandy beach, it feeds a green algae (Ulva) proliferation. In order to control its nitrogen fluxes, the stream was partly diverted through a part of the marsh (9 ha), before it was allowed to go back to the main bed. Thus a collapsible weir was set up during several springs and summers, i.e. the growing period of Ulva. The nitrate stripping off the going through flux is within a 30 to 90 % range,that is important (175 kg N03... |
| Tipo: Text |
Palavras-chave: Algae; Nitrogen; Ulva; Nitrate depletion; Costal marsh; Algue; Azote; Ulva; Abattement de nitrate; Marais côtier. |
| Ano: 1999 |
URL: http://archimer.ifremer.fr/doc/1999/rapport-64.pdf |
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| Medale, Francoise; Boujard, Thierry; Vallee, Frédéric; Blanc, Denise; Mambrini, Muriel; Roem, Arjen; Kaushik, Sadasivam. |
| High energy extruded diets were formulated to contain the same level of protein supplied either by soy protein concentrate (SPC) or fish meal. Three experiments were performed in order to measure voluntary feed intake and feed waste, faecal losses and soluble losses of nitrogen and phosphorus in rainbow trout (average body weight: 100 g). Voluntary feed intake and growth performance of fish fed with demand feeders were not different when diets contained 0, 50 or 75 % SPC instead of fish meal. Total replacement of fish meal by SPC led to a significant decrease in feed intake and resulted in poor growth. This was partly due to methionine deficiency in the SPC based diet. With the addition of crystalline DL-methionine in the diets, an improvement of feed... |
| Tipo: Text |
Palavras-chave: Digestibilité; Excrétion; Azote; Phosphore; Protéine de soja; Ingestion volontaire; Truite arc-en-ciel; Digestibility; Excretion; Nitrogen; Phosphorus; Soy protein; Voluntary feed intake; Rainbow trout. |
| Ano: 1998 |
URL: https://archimer.ifremer.fr/doc/1998/publication-871.pdf |
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| Silva, Celine; Raillard, Marieke; Bodoy, Alain; Hussenot, Jerome. |
| In spring 2001, during a complete tidal cycle, nitrogen fluxes between the sea and the salt marsh were calculated. The marsh (1198 m2) covered in 75 % by halophytes, with 46 % by the sea purslane, Halimione portulacoides. The nitrogen balance shows that the salt marsh imports nitrogen micro-particules (2,09 g) by sedimentation, exports dissolved nitrogen (4,13 g), and that the macro-element part (-1,02 g in fauna and vegetable refuse) in the global mass balance (3,06 g) is not unimportant. Nitrogen fluxes are mainly under inorganic form for the incoming flux (mainly NO3), and under organic form for the outgoing flux. The halophyte vegetation of this marsh seems to play thus a dominating role in the tidal nitrogen exchanges, by a mechanical action on the... |
| Tipo: Text |
Palavras-chave: Marais salé; Halophytes; Azote; Bilan de masse; Halimione portulacoides; Salicornes; Salt marsh; Halophytes; Nitrogen; Mass balance; Halimione portulacoides; Sea purslane; Sampshire. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/00045/15597/13000.pdf |
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| Feuillet-girard, Michelle; Heral, Maurice; Sornin, Jean-marc; Deslous-paoli, Jean-marc; Robert, Jean-michel; Mornet, Francoise; Razet, Daniel. |
| The respective influences of the sediment and of oyster (Crassostrea gigas) farming on the accumulation and the recycling of different forms of organic and inorganic nitrogen are described. Fluxes of dissolved inorganic and organic forms of nitrogen were studied between the water column, the water overlying the sediment and the pore waters, while for particulate forms the fluxes were studied between suspended material, the "biodeposits" (faeces and pseudofaeces of Crassostrea) and the sediment. The flux of inorganic nitrogen amounts to 10.5 106 g.m(-2). Yr(-1), while that of organic nitrogen is half this figure. The particulate flux is 15.106 g.m(-2).yr(-1). On the other hand, the phytoplanktonic nitrogen accounts for only 6% of the total particulate... |
| Tipo: Text |
Palavras-chave: Marenne Oleron; Sediment; Pore water; Interface; Crassostrea gigas; Nitrogen; Marennes Oléron; Sédiment; Eau interstitielle; Adsorption; Interface; Crassostrea gigas; Azote. |
| Ano: 1988 |
URL: http://archimer.ifremer.fr/doc/1988/publication-2878.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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| Chamroux, S.; Boucher, G.. |
| Chemical and Biological evolution of sediments in closed circuit : I. Nitrogen and bacteria. A series of well controlled sea water closed circuit sand filters allowed the study of chemical and biological regulation processes in the sediment. Bacteria, Nitrogen chemistry and meiofauna were mainly investigated. The evolution of the different forms of nitrogen is rather similar, whatever the organic matter flow in the sediment. As long as the amount of organic input works as limiting factor, bacteria densities are proportional to its flow. No correlation was found between bacteria and chemical parameters in the sand or in the water. The temperature does not seem to play a determinant part neither in the evolution of bacteria nor in the mineralization of... |
| Tipo: Text |
Palavras-chave: Circuit clos; Sédiment; Bactéries; Matière organique; Azote; Closed circuit; Sediment; Bacteria; Organic matter; Nitrogen. |
| Ano: 1979 |
URL: http://archimer.ifremer.fr/doc/00305/41652/40861.pdf |
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| 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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| Pete, Romain; Malet, Nathalie. |
| Afin d’apporter des éléments de réponse quantitatifs à ces questions, un outil numérique GAMELag a été développé en collaboration avec l’UMR ECOSYM en se basant sur l’approche LOICZ. Par suite ce modèle « simple » (modèle en boîtes avec calcul de bilan de matière aux interfaces) a été affiné au cours de phases successives de validation. La présente étude vise à déployer le modèle écosystémique « GAMELag » permettant d’évaluer les flux et stock d’azote et de phosphore dans la lagune de Biguglia. L’objectif est de i) valider le fonctionnement du modèle sur la lagune de Biguglia et ii) de fournir aux gestionnaires des résultats en réponse à différents scenarios hydroclimatiques (année sèche/pluvieuse) ou selon différentes options de gestion, notamment... |
| Tipo: Text |
Palavras-chave: Modèle écosystémique; GAMELag; Flux; Stock; Azote; Phosphore; Scenarios écologiques. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00604/71565/70025.pdf |
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| Registros recuperados: 26 | |
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