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| Registros recuperados: 10 | |
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| Gentilhomme, V; Raimbault, P. |
| The uptake and regeneration of four forms of nitrogen NO3-, NO2-, NH4+ and urea) have been studied, in the euphotic layer of a frontal area (Algerian current), in relation with hydrological, chemical and biological parameters. Ln this area vertical stratification is pronounced; a deep chlorophyll maximum at the bottom of the euphotic layer is present. Results show the importance of measuring urea uptake and regeneration in the study of nitrogen cycling, because this component can be regenerated as rapidly as ammonia, and is a source of nitrogen for phytoplankton. Other results show the oxidation of ammonia to nitrate in the euphotic layer, and particularly at the base of this layer. This nitrification is a source of in situ regenerated nitrate, and could... |
| Tipo: Text |
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| Ano: 1994 |
URL: http://archimer.ifremer.fr/doc/00099/21012/18638.pdf |
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| Gaudy, R; Youssara, F; Diaz, F; Raimbault, P. |
| Zooplankton biomass was measured at 20 stations located along five coastal-offshore transects in the Gulf of Lions (NW Mediterranean) during spring 1998 and winter 1999, using two nets equipped with 200 and 80 Pm mesh. Biomass was twice as abundant in spring. It increased toward the coast and the west of the gulf and was positively correlated to chlorophyll, primary production and organic particulate matter and negatively to temperature and salinity. The enrichment effect of Rhone river input and the oligotrophic influence of the north Mediterranean current (NMC) were the main distribution factors of zooplankton biomass. Higher biomass was obtained in coastal stations with the 80 mum net, which sampled more efficiently young larval stages and nauplii.... |
| Tipo: Text |
Palavras-chave: Zooplankton; Métabolisme; Cycle saisonnal; Golfe du Lion; Zooplankton; Metabolism; Seasonal cycle; Gulf of Lions. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/00321/43262/42993.pdf |
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| Raimbault, P; Slawyk, G; Boudjellal, B; Coatanoan, Christine; Conan, Pascal; Coste, B; Garcia, N; Moutin, T; Pujo-pay, M. |
| Biomass, inorganic carbon and nitrogen uptake, ammonium regeneration, nitrification, and vertical flux of particulate matter were measured in the equatorial Pacific at 21 daily productivity stations occupied on a meridional transect (150 degrees W) between 1 degrees N and 16 degrees S. Three areas could be distinguished along the transect: (1) the equatorial area between 1 degrees N and 6 degrees S, where nitrate concentrations were typically eutrophic, reaching up to 3 mu g-at L(-1) in surface waters; (2) an intermediate mesotrophic area between 6 degrees and 10 degrees S, where surface nitrate concentrations decreased from 1 mu g-at L(-1) to zero; and (3) the oligotrophic area beyond 10 degrees S, characterized by warm and nitrate poor waters. Although... |
| Tipo: Text |
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| Ano: 1999 |
URL: http://archimer.ifremer.fr/doc/00172/28366/26656.pdf |
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| Herbland, Alain; Le Bouteiller, A; Raimbault, P. |
| A study of the size structure of chlorophyll a (Chla) covering the major part of the equatorial Atlantic Ocean from 5 degree N to 5 degree S leads to the conclusion that seasonal nutrient enrichment in the open eastern equatorial Atlantic does not drastically affect the size distribution of the primary producers: 90% of the total Chla is everywhere contained in the < 20 mu m fraction on the average. In the coastal upwelling near Dakar, this percentage is less than 60%, for the same range of chla concentrations. In the equatorial region the percentage of < 1 mu m Chla is the same in the deep chlorophyll maximum located at the top of the nitracline during the warm season and in the subsuperficial maximum of the upwelling. |
| Tipo: Text |
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| Ano: 1987 |
URL: http://archimer.ifremer.fr/doc/00267/37855/35936.pdf |
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| Leblanc, K; Queguiner, B; Raimbault, P; Garcia, N. |
| A one-year survey of the sedimenting particulate material was conducted at the SOFi site located on the edge of the continental slope in the Gulf of Lions (Northwestern Mediterranean) between September 1999 and December 2000. The main focus of this paper was to establish an annual budget of biogenic silica export, to describe the seasonnal pattern of Si fluxes in relation to the organic and mineral C fluxes and to quantify the Si/C decoupling processes during sedimentation. The pattern of the downward flux of BSi was partly typical with increased daily sedimentation rates during spring followed by smaller peaks during summer. However, an unusual sedimentation event was recorded in the bottom trap in February before the spring thermal stratification... |
| Tipo: Text |
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| Ano: 2005 |
URL: https://archimer.ifremer.fr/doc/00320/43091/42628.pdf |
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| Durrieu De Madron, X; Denis, L; Diaz, F; Garcia, N; Guieu, C; Grenz, C; Loye-pilot, Md; Ludwig, W; Moutin, T; Raimbault, P; Ridame, C. |
| Shelf-slope exchanges and budgets of organic and inorganic nutrients are calculated for the Gulf of Lion continental margin in the northwestern Mediterranean. Computations are based on data from three seasonal marine surveys performed in March 1998, June 1998 and January 1999 in the framework of the French Programme National d'Environnement Cotier. A Land-Ocean Interactions in the Coastal Zone type box model is used to calculate the advective exchanges between the shelf and the adjacent open sea and to estimate the budgets of non-conservative elements (DIP, DIN, DOP, DON, DOC, POC, PON, POP). These budgets consider river discharges, urban sewage supply, atmospheric deposition, and fluxes at the water-sediment and shelf-slope interfaces. Uncertainties on... |
| Tipo: Text |
Palavras-chave: Mer Méditerranée; Echanges côte-large; Fonctionnement de l’écosystème; Cycle du carbone; Bilan de sels nutritifs; Mediterranean Sea; Shelf-slope exchanges; Ecosystem functioning; Carbon cycle; Nutrients budget. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/00301/41236/40426.pdf |
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| Leblanc, K; Queguiner, B; Garcia, N; Rimmelin, P; Raimbault, P. |
| A study of the biogeochemical cycle of silicon has been conducted in the Gulf of Lion (NW Mediterranean) from September 1999 to September 2000. Most of the year the study site was under the influence of the NW Mediterranean Current, characterized by oligotrophic conditions. A seasonal pattern of silicon stocks was found, showing an inverse annual distribution of biogenic silica and lithogenic silica. Biogenic silica integrated stocks were higher during spring and summer (21.5 and 19.3 mmol m(-2)) due to siliceous phytoplankton Si uptake and build-up of biomass. By contrast lithogenic silica integrated stocks were highest during the fall and winter (61.8 and 45.0 mmol m(-2)), which may be explained by a higher degree of turbulence of the water column,... |
| Tipo: Text |
Palavras-chave: NW Mediterranean; Biogenic silica; Phytoplanktonic community; Limiting nutrient; Seasonal cycle. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/00320/43092/42629.pdf |
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| Registros recuperados: 10 | |
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