Consulta: creatorFacets:"Raimbault, P"
Registros recuperados: 10
Data/hora: 12/06/2024 14:29:25

Does the nutrient enrichment of the equatorial upwelling influence the size structure of phytoplankton in the Atlantic Ocean?
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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 &lt; 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 &lt; 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
Ano: 1987
URL: http://archimer.ifremer.fr/doc/00267/37855/35936.pdf

Biomass, metabolism and nutrition of zooplankton in the Gulf of Lions (NW Mediterranean)
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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

Variabilité hydrologique et biologique du golfe du Lion. I. Transports en azote et productivité potentielle
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Conan, P; Pujo-pay, M; Raimbault, P; Leveau, M.
A monthly time-series of the seasonal evolution of the North Mediterranean Current (NMC) and of nitrogen flux across a transect (5 degrees 12'5 E between 43 degrees 10'N and 42 degrees 50'N) at the entrance of the Gulf of Lions was carried out over two years. The NMC exhibited two distinct structures: a winter structure (from November to May) characterised by strong mesoscale and interannual variations in which the current was 20 to 30 km width, about 400 m depth and velocity scaled between 5 and more than 40 cm s(-1); and a summer structure (from May to November) which was less sensitive to mesoscale variations but showing large interannual variability. The current was located more offshore, was wider and shallower than the one in winter and velocity...
Tipo: Text
Palavras-chave: Hydrologie; Variabilité à méso-échelle; Azote; Flux de matière; Bilan; Hydrology; Mesoscale variability; Nitrogen; Flux; Budget.
Ano: 1998
URL: http://archimer.ifremer.fr/doc/00325/43638/43249.pdf

Absorption et régénération de l'azote dans la zone frontale du courant Algérien (Méditerranée Occidentale) : réévaluation de la production nouvelle
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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
Ano: 1994
URL: http://archimer.ifremer.fr/doc/00099/21012/18638.pdf

Nutrients and carbon budgets for the Gulf of Lion during the Moogli cruises
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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

Conditions hydrologiques, chimiques et production primaire dans les upwellings du Perou et des iles Galapagos, en regime d'hivers austral (Campagne Paciprod)
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Minas, Hj; Coste, B; Minas, M; Raimbault, P.
The Paciprod Cruise of the R/V Jean-Charcot was devoted to study upwellings and their biological consequences in the coastal area of Peru and in the equatorial divergence zone around the Galapagos Archipelago. Main objectives, methodology and shipboard experimentations have been reported.
Tipo: Text
Ano: 1990
URL: http://archimer.ifremer.fr/doc/00268/37956/36037.pdf

Efficiency of the silicate pump at a coastal oligotrophic site in the Mediterranean Sea
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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
Ano: 2005
URL: https://archimer.ifremer.fr/doc/00320/43091/42628.pdf

Carbon and nitrogen uptake and export in the equatorial Pacific at 150 degrees W: Evidence of an efficient regenerated production cycle
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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
Ano: 1999
URL: http://archimer.ifremer.fr/doc/00172/28366/26656.pdf

Silicon cycle in the NW Mediterranean Sea: seasonal study of a coastal oligotrophic site
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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

Variabilité hydrologique et biologique du golfe du Lion. II. Productivité sur le bord interne du courant
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Conan, P; Pujo-pay, M; Raimbault, P; Leveau, M.
An estimation of the annual productivity in the Gulf of Lions has been made in the 0-100 m layer using a Let-Go system, with monthly measurements at a fixed station. A value of 140 to 150 g m(-2) a(-1) of C is found, of which around 75 % occurs in the upper 50 m. The seasonal production is described according to three distinct patterns during the two hydrological seasons: (1) variable production in winter; (2) surface bloom in late winter; (3) homogeneous and mean production in summer with a clear Deep Chlorophyll Maximum. The hydrological winter phase represented 60 % of total annual production. The seasonal duality of the hydrodynamic system and the mesoscale variations of the Northern Mediterranean Current account for the variability and the evolution...
Tipo: Text
Palavras-chave: Production primaire; Bilan; Nitrate; Chlorophylle; Cycle saisonnier; Primary production; Budget; Nitrate; Chlorophyll; Seasonal cycle.
Ano: 1998
URL: http://archimer.ifremer.fr/doc/00325/43639/43248.pdf