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| Registros recuperados: 425 | |
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| Piriou, Jean-yves; Chapron, Victorien; Annezo, Jean-pierre. |
| The gulf of Morbihan, without manifesting any pronounced signs of eutrophication, has, in 1995, three sites of green algae proliferation: the Auray river estuary, the branches of the Vannes and Séné estuary, as well as the outlet of the Noyalo's estuary. They are also the three sectors of the gulf that receive the most nutrient salts, in particular, nitrogen, which is a determining factor in the development of nitrophilic green algae (Ménesguen and Piriou 1995). During spring the nitrogen seems to come as much from urban sources (Vannes, Auray) as from agricultural sources coming from the northern catchment areas of the gulf. |
| Tipo: Text |
Palavras-chave: Morbihan gulf; Eutrophication; Nitrogen; Green seaweed; Green algae; Eutrophisation; Golfe du Morbihan; Azote; Algues vertes. |
| Ano: 1995 |
URL: http://archimer.ifremer.fr/doc/1995/rapport-2084.pdf |
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| Lauter, Lukas; Hochenauer, Roman; Buchegger, Christoph; Bohn, Marcel; Lengauer, Walter. |
| The solubilities of the most common grain -growth inhibitors (GGIs) Cr, V, Ta, Mo, Nb, Zr and certain combinations there of in the binder phase of WC-Co hardmetals as well as hardmetals of the type WCTiC-TiN-TaC-NbC-Co containing an fcc MC carbide (or carbonitride) phase "MC"("WC-MC-Co" hardmetals) were analysed by means of WDS-EPMA. The carbon potential of the binder phase was fixed at its highest and lowest maxima by the presence of either graphite or eta (M6C) phases. In case of low-carbon hardmetals the composition of M6C, and in the MC-containing hardmetals the composition of the MC phase, was analysed. Two types of solubilities were determined. The first type was measured after controlled cool-down from liquid-phase sintering temperature and... |
| Tipo: Text |
Palavras-chave: Hardmetal; Cemented carbides; Grain-growth inhibitor; Nitrogen; Binder phase; Solubility; EPMA. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00332/44332/44155.pdf |
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| Huang, Bing; Marchand, Justine; Blanckaert, Vincent; Lukomska, Ewa; Ulmann, Lionel; Wielgosz-collin, Gaëtane; Rabesaotra, Vony; Moreau, Brigitte; Bougaran, Gael; Mimouni, Virginie; Morant-manceau, Annick. |
| Nitrogen (N) and phosphorus (P) limitations induce triacylglycerol (TAG) accumulation and membrane lipid remodelling in the marine diatom Phaeodactylum tricornutum. However, a clear understanding of the metabolic reorientation is still lacking. Carbon partitioning is of great interest because this microalga produces various highly valuable molecules such as lipids and polyunsaturated fatty acids. This study compared growth, photosynthetic activity, biochemical and transcriptional responses of P. tricornutum throughout batch culture under N or P limitation. The integrated results show that the photosynthetic intensity was greatly reduced under N or P limitation. Under N limitation, the degradation and re-use of cellular N-containing compounds contributed to... |
| Tipo: Text |
Palavras-chave: Betaine lipid; Lipid remodelling; Microalga; Nitrogen; Phosphorus; Polyunsaturated fatty acid. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00491/60249/63861.pdf |
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| Longphuirt, Sorcha Ni; Lim, Jae-hyun; Leynaert, Aude; Claquin, Pascal; Choy, Eun-jung; Kang, Chang Keun; An, Shu. |
| The importance of intertidal flats as areas of nitrogen filtering has become increasingly apparent in recent times. TO understand fully the cycling of this nutrient. in these areas of high metabolic activity, it is necessary to elucidate the influence of microphytobenthos (MPB) on stocks of ammonium and nitrate in surface areas. In this study, we aimed to quantity nitrogen uptake and relate it to the in Situ concentrations and environmental conditions to which MPB are exposed. In an estuarine system on the Korean Peninsula, we conducted kinetic experiments using N-15 stable isotopes and core sampling over the tidal cycle to determine the temporal evolution of porewater nutrient concentrations and the migration of MPB. The results revealed a range of K-s... |
| Tipo: Text |
Palavras-chave: N 15 stable isotope; Porewater; Microphytobenthos; Kinetic; Nitrogen. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6622.pdf |
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| Lemonnier, Hugues; Faninoz, Sebastien. |
| An experiment was conducted in six earthen ponds with 20 shrimps m(-2) Litopenaeus stylirostris (Stimpson) during the warm season in New Caledonia to study the dynamics of wastes in relation with water exchange rate (WER). The nitrogen budget was established, taking into account the different forms of nitrogen in the water, sediment, feed and shrimp. Data from a wide range of treatments applied in unreplicated ponds were treated using regression analysis to establish the relationship between WER and partial nitrogen budget, sediment characteristics and shrimp performance. To compare effluent quality between treatments during the season, data were analysed using the non-parametric sign test. The water outflow was characterized by a decrease in the... |
| Tipo: Text |
Palavras-chave: New Caledonia; Nitrogen; Water exchange; Shrimp; Sediment quality; Effluent. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-1811.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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| 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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| Huang, Bing; Mimouni, Virginie; Lukomska, Ewa; Morant-manceau, Annick; Bougaran, Gael. |
| The domesticated marine microalga Diacronema lutheri is of great interest for producing various highly valuable molecules like lipids, particularly long‐chain polyunsaturated fatty acids (LC‐PUFA). In this study, we investigated the impact of phosphorus (P) and nitrogen (N) starvation on growth, carbon fixation (photosynthetic activity) and partitioning, and membrane lipid remodeling in this alga during batch culture. Our results show that the photosynthetic machinery was similarly affected by P and N stress. Under N starvation, we observed a much lower photosynthetic rate and biomass productivity. The degradation and re‐use of cellular N‐containing compounds contributed to triacylglycerol (TAG) accumulation. On the other hand, P‐starved cells maintained... |
| Tipo: Text |
Palavras-chave: Carbon partitioning; Diacronema lutheri; Nitrogen; Phosphorus; Polyunsaturated fatty acid. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00619/73071/72204.pdf |
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| Belloni, Bruno; Sartoretto, Stephane; Cresson, Pierre; Bouchoucha, Marc; Guillou, Gael; Lebreton, Benoit; Ruitton, Sandrine; Harmelin-vivien, Mireille. |
| The coralligenous ecosystem is one of the biodiversity hotspots in the Mediterranean Sea. This study aims at determining (i) the organic matter (OM) sources at the base of the food web in a coralligenous ecosystem near Marseille (Cap Caveau, Frioul Island) and (ii) the global functional structure of its community. For that purpose, C and N stable isotope analyses were performed on 78 compartments or species collected in this habitat between 30 and 40 m depth. Results suggested that the pelagic particulate organic matter (POM), mainly composed of phytoplankton, was the main OM source fuelling coralligenous food webs, followed by sedimented organic matter (SOM) and some macrophytes. At least three level of consumers were identified from... |
| Tipo: Text |
Palavras-chave: Food webs; Coralligenous ecosystem; Stable isotopes; Carbon; Nitrogen. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00483/59511/62396.pdf |
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| Bréchet, Laëtitia; Courtois, Elodie A.; Saint-germain, Thomas; Janssens, Ivan A.; Asensio, Dolores; Ramirez-rojas, Irene; Soong, Jennifer L.; Van Langenhove, Leandro; Verbruggen, Erik; Stahl, Clément. |
| Tropical soils are a major contributor to the balance of greenhouse gas (GHG) fluxes in the atmosphere. Models of tropical GHG fluxes predict that both the frequency of drought events and changes in atmospheric deposition of nitrogen (N) will significantly affect dynamics of soil carbon dioxide (CO2) and methane (CH4) production and consumption. In this study, we examined the combined effect of a reduction in precipitation and an increase in nutrient availability on soil CO2 and CH4 fluxes in a primary French Guiana tropical forest. Drought conditions were simulated by intercepting precipitation falling through the forest canopy with tarpaulin roofs. Nutrient availability was manipulated through application of granular N and/or phosphorus (P) fertilizer to... |
| Tipo: Text |
Palavras-chave: Carbon dioxide; Drought; Fertilization; Methane; Nitrogen; Phosphorus; Soil GHG fluxes; Tropical forest. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00595/70694/68903.pdf |
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| Van Langenhove, Leandro; Verryckt, Lore T.; Bréchet, Laëtitia; Courtois, Elodie A.; Stahl, Clement; Hofhansl, Florian; Bauters, Marijn; Sardans, Jordi; Boeckx, Pascal; Fransen, Erik; Peñuelas, Josep; Janssens, Ivan A.. |
| Atmospheric deposition is an important component of the nutrient cycles of terrestrial ecosystems, but field measurements are especially scarce in tropical regions. In this study we analysed 15 months of precipitation chemistry collected in an old growth tropical forest located in French Guiana. We measured nutrient inputs via bulk precipitation and throughfall and used the canopy budget model to estimate nutrient fluxes via canopy exchange and dry deposition. Based on this method we quantified net fluxes of macronutrients and compared their contribution to internal cycling rates via litterfall. Our results suggest that while atmospheric deposition of nitrogen was relatively high (13 kg ha−1 year−1), and mainly in organic forms, the N inputs via litterfall... |
| Tipo: Text |
Palavras-chave: Throughfall; Litterfall; Nutrient cycling; Nitrogen; Phosphorus; Potassium. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00629/74123/73572.pdf |
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| Jauzein, Cecile; Collos, Yves; Laabir, Mohamed; Vaquer, Andre. |
| Uptake rates of three potential N-sources (ammonium, nitrate and N-urea) and two potential C-sources (HCO(3)(-) and C-urea) were estimated during growth of Alexandrium catenella in both light and dark phases. According to the variations observed in (13)C-isotopic ratio, A. catenella cells were not able to use C-urea. Furthermore, decreases in (13)C cell content during darkness revealed a probably high involvement of C recently fixed in dark respiration. Dark N-uptake capacities of A. catenella were characterized by dark/light uptake ratio of 27%, 43% and 65% for NO(3)(-), NH(4)(+) and N-urea, respectively. An accumulation of C-rich compounds during the light period was highlighted through strong diel variations in C:N ratio and would provide C and energy... |
| Tipo: Text |
Palavras-chave: Diel cycle; Dark uptake; Nitrogen; Carbon; Uncoupling; Alexandrium catenella. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00056/16699/14199.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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| Martin-jezequel, Veronique; Calu, Guillaume; Candela, Leo; Amzil, Zouher; Jauffrais, Thierry; Sechet, Veronique; Weigel, Pierre. |
| Over the last century, human activities have altered the global nitrogen cycle, and anthropogenic inputs of both inorganic and organic nitrogen species have increased around the world, causing significant changes to the functioning of aquatic ecosystems. The increasing frequency of Pseudo-nitzschia spp. in estuarine and coastal waters reinforces the need to understand better the environmental control of its growth and domoic acid (DA) production. Here, we document Pseudo-nitzschia spp. growth and toxicity on a large set of inorganic and organic nitrogen (nitrate, ammonium, urea, glutamate, glutamine, arginine and taurine). Our study focused on two species isolated from European coastal waters: P. multiseries CCL70 and P. australis PNC1. The nitrogen... |
| Tipo: Text |
Palavras-chave: Pseudo-nitzschia; Toxic diatoms; Nitrogen; Amino acids; Domoic acid. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00308/41912/41188.pdf |
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| Registros recuperados: 425 | |
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