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| Registros recuperados: 425 | |
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| 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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| Garnier, Matthieu; Carrier, Gregory; Rogniaux, Helene; Nicolau, Elodie; Bougaran, Gael; Saint-jean, Bruno; Cadoret, Jean-paul. |
| Understanding microalgal lipid accumulation under nitrogen starvation is of major interest for biomass feedstock, food and biofuel production. Using a domesticated oleaginous algae Tisochrysis lutea, we performed the first comparative proteomic analysis on the wild type strain and a selected lipid over-accumulating mutant. 2-DE analysis was made on these strains cultured in two metabolic conditions, with and without nitrogen deprivation, which revealed significant differences in proteomes according to both strain and nitrogen availability. Mass spectrometry allowed us to identify 37 proteins that were differentially expressed between the two strains, and 17 proteins regulated by nitrogen starvation concomitantly with lipid accumulation. The proteins... |
| Tipo: Text |
Palavras-chave: Microalgae; Biotechnology; Lipid; Nitrogen; Proteomic; Selection. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00179/29012/27470.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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| 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; 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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| Roque D'Orbcastel, Emmanuelle; Blancheton, Jean-paul; Boujard, Thierry; Aubin, Joel; Moutounet, Yves; Przybyla, Cyrille; Belaud, Alain. |
| European water legislation enforces increasingly restrictive measures with regards to reduction of water consumption and waste emission in order to minimise the potential environmental impact of the agro industry sector. Fish farms are particularly concerned, but legislation covering effluent discharge varies significantly from country to country. However, recommendations and directives from institutional, national or regional bodies suggest the enforcement of increasingly strict waste reduction measures and the development of waste treatment. Before treatment, it is necessary to evaluate waste production in terms of composition and quantity. The waste quantification methods used today for fish culture systems are either based on direct measurements of... |
| Tipo: Text |
Palavras-chave: Phosphorus; Nitrogen; Suspended solids; Trout farm; Waste. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-6822.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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| Lema, Anais Kimberley; Latimier, Marie; Nezan, Elisabeth; Fauchot, Juliette; Le Gac, Mickael. |
| The factors responsible for inducing the synthesis of toxins and responses from toxic phytoplankton blooms remain unclear. In this study we compare the influence of genotypic (at both the intra and interspecific levels) and environmental factors (nutrient concentration and ratio) on growth (in terms of cell densities) and domoic acid (DA) production in three Pseudo-nitzschia species: P. australis, P.pungens and P.fradulenta. A strong phosphate effect was detected. More precisely, a low initial concentration in phosphate, even at high initial nitrogen and silicate concentrations, induced the highest DA concentrations and the lowest cell densities in all strains/species studied. In contrast, a low initial concentration of nitrogen and silicate combined, with... |
| Tipo: Text |
Palavras-chave: Pseudo-nitzschia strains; Domoic acid; Ratio; Phosphate; Nitrogen. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00377/48849/49397.pdf |
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| Zheng, Li-wei; Hsiao, Silver Sung-yun; Ding, Xiao-dong; Li, Dawei; Chang, Yuan-pin; Kao, Shuh-ji. |
| Total organic carbon to total nitrogen ratios (C/N) and their isotopic compositions (δ13CTOC and δ15NTN) are oft-applied proxies to discern terrigenous from marine-sourced organics and to unravel ancient environmental information. In high depositional Asian marginal seas, the inclusion of N-bearing minerals in the bulk sediment dilutes or masks signals sought after in δ15N and δ13C analyses, thus leading to incorrect and even contradictory interpretations. We used KOH-KOBr to separate operationally defined total organic matter into oxidizable (labile) and residual fractions for content and isotope measurements. In a sediment core in the Okinawa Trough, significant amounts of carbon and nitrogen existed in the residual phase, in which the C/N ratio was ~9,... |
| Tipo: Text |
Palavras-chave: Carbon; Nitrogen; Isotope; Okinawa Trough; Sediment; Total organic carbon. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00295/40584/39503.pdf |
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| Huang, Bing; Marchand, Justine; Thiriet-rupert, Stanislas; Carrier, Gregory; Saint-jean, Bruno; Lukomska, Ewa; Moreau, Brigitte; Morant-manceau, Annick; Bougaran, Gael; Mimouni, Virginie. |
| Nitrogen (N) and phosphorus (P) limitations induce neutral lipid accumulation and membrane lipid remodeling in the domesticated oleaginous microalga Tisochrysis lutea. This study compared growth, photosynthetic activity, biochemical and transcriptional responses of T. lutea throughout batch cultures under N or P limitation compared with non-limiting nutrient condition (NP). The results show that, under N limitation, the breakdown and re-use of cellular N-containing compounds contributed to carbohydrates and further triacylglycerol (TAG) accumulation, where the accumulation of docosahexaenoic acid (DHA) in neutral lipids might mainly be derived from the recycling of membrane polar lipids. Conversely, P limitation did not hinder the photosynthetic capacity;... |
| Tipo: Text |
Palavras-chave: Tisochrysis lutea; Phosphorus; Nitrogen; Lipid remodeling; Betaine lipid; Polyunsaturated fatty acid. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00492/60409/64776.pdf |
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| Deborde, J; Anschutz, P; Auby, Isabelle; Gle, C; Commarieu, M; Maurer, Daniele; Lecroart, P; Abril, G. |
| The hypothesis of nutrient-rich pore-waters seeping at low tide through sediments to channel waters, which drain tidal flats during ebb, was evaluated in the Arcachon lagoon. The back of the bay is affected by freshwater inputs and underground freshwater discharges. The upper part of tidal flat consists of permeable sandy sediments, which are covered by a muddy sediment layer on the lower part. Permeable sediments outcrop in the bed of channel web. Surface water chemistry and early diagenesis processes in sediment were estimated by collecting channel web waters and cores on a tidal flat and in channels at different seasons and time scales. Waters from tidal creeks are under-oxygenated, and enriched in reduced solutes. Muddy sediments showed evidences of... |
| Tipo: Text |
Palavras-chave: Arcachon Bay; Pore waters seeping; Nitrogen; Phosphorus; Organic matter mineralization; Tidal creek water; Tidal pump. |
| Ano: 2008 |
URL: https://archimer.ifremer.fr/doc/2008/publication-3927.pdf |
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| Guazzelli Gonzalez, Julio; Ménard, Frédéric; Le Loc'H, François; Agrelli De Andrade, Humber; Pontes Viana, Andréa; Ferreira, Valdimere; Frédou, Flávia Lucena; Lira, Alex Souza; Munaron, Jean-marie; Frédou, Thierry. |
| We investigated the trophic niches and the resource partitioning of two snook species, the common (Centropomus undecimalis) and the fat snook (C. parallelus), in four tropical estuaries of the northeastern Brazil, using stable isotope analyses of carbon (δ13C) and nitrogen (δ15N). Fish specimens, mainly juveniles, basal resources and a primary consumer were collected in 2015 during dry and rainy seasons in all estuaries, which exhibited differences in system size, geomorphologic shapes, levels of sea access and anthropic pressures. Potential effect of factors like fish body length, estuary and seasonality on isotope ratios were investigated. Positive relationships between the size of fish and δ15N values were found, regardless the species. Our results... |
| Tipo: Text |
Palavras-chave: Brackish water fish; Trophic relationships; Carbon; Nitrogen; Centropomus. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00506/61767/65745.pdf |
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| Garnier, Matthieu; Bougaran, Gael; Pavlovic, Marija; Berard, Jean-baptiste; Carrier, Gregory; Charrier, Aurelie; Le Grand, Fabienne; Lukomska, Ewa; Rouxel, Catherine; Schreiber, Nathalie; Cadoret, Jean-paul; Rogniaux, Helene; Saint-jean, Bruno. |
| Haptophytes are a diverse monophyletic group with a worldwide distribution, known to be significantly involved in global climate regulation in their role as a carbon sink. Because nitrogen is a major limiting macronutrient for phytoplankton in oceans and for cultures of microalgae, understanding the involvement of nitrogen availability in haptophyte carbon partitioning is of global and biotechnological importance. Here, we made an ecophysiological study coupled with comprehensive large scale proteomic analysis to examine differences of behavior in reaction to nitrogen availability changes between a wild type strain of Tisochrysis lutea (WTc1) and a mutant strain (2Xc1) known to accumulate more storage lipids. Strains were grown in chemostats and studied... |
| Tipo: Text |
Palavras-chave: Algae; Isochrysis; Lipids; Nitrogen; Reverse genomic: proteomic. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00356/46702/46904.pdf |
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| Registros recuperados: 425 | |
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