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Registros recuperados: 10 | |
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Vanwambeke, F; Christaki, U; Gaudy, R. |
The microbial food web structure, the carbon flux between mesozooplankton and the microbial community, and the importance of heterotrophs in the diet of marine zooplankton were investigated in the surface layer of a pelagic area of the NW Mediterranean Sea in five 24-h shipboard experiments: Heterotrophic flagellates grazed 65 % to 91 % of the bacterial production. However, the protozoan community seems also to utilize alternative carbon sources, such as small autotrophs. In most of the experiments, the estimated production of the protozoan > 7 mu m was sufficient to supply mesozooplankton carbon demand. Copepods stimulated bacterial growth, presumably through excretion and preference for heterotrophic flagellates. Variations of the experimentally... |
Tipo: Text |
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Ano: 1996 |
URL: http://archimer.ifremer.fr/doc/00096/20727/18364.pdf |
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Gaudy, R; Pagano, M. |
The zooplankton of an eutrophic brackish lagoon (Etang de Berre), near Marseille (France) was studied during an annual cycle. It was characterized by large populations of a pelagic copepod (Acartia tonsa ). Grazing on natural particles by this species was investigated. Adults were able to use an extended range of particle sizes, but showed selectivity for particles concentration was observed (14 mu m). Temperature and particles concentration appear to modify the selectivity behavior. Juvenile stages could also catch particles of various size but did not show the same selectivity for the peak particles as adults. Daily food ration was high comparatively to open-sea copepods. Taking into account several results obtained on food ration, egg production and... |
Tipo: Text |
Palavras-chave: Copepoda; Lagoons; Energy budget; Seasonal variations; Particle concentration; Zooplankton; Food availability; Temperature effects; Nutrition. |
Ano: 1984 |
URL: http://archimer.ifremer.fr/doc/1984/acte-1526.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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Gaudy, R; Pagano, M; Cervetto, G; Saintjean, L; Verriopoulos, G; Beker, B. |
Feeding, respiration, and ammonia excretion of Acartia tonsa were studied in a brackish lagoon, near Marseilles (Southern France). The experiments were performed during the same season in two successive years, using naturally occurring particles as food. Strong variations in both quantity and quality of food particles were recorded between the two series of experiments. The ingestion of particles according to their size was studied by means of the Coulter Counter technique. Females ingested more food than males. In both sexes, there was a tendency to select median to large particles, regardless of the shape of the particles-size spectrum. In 1990, the specific production rate, deduced from the energy budget, was equivalent to or greater than the observed... |
Tipo: Text |
Palavras-chave: Acartia tonsa; Feeding; Metabolism; Production. |
Ano: 1996 |
URL: http://archimer.ifremer.fr/doc/00096/20731/18368.pdf |
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Youssara, F; Gaudy, R. |
Zooplankton from the upper 200 m of the Almeria-Oran frontal region, (east of the Alboran sea, western Mediterranean) was sampled during winter 1997, using two nets equipped with 200 and 80 mum mesh. Eight sites representative of the different hydrodynamic structures (Mediterranean water, geostrophic Atlantic jet, associated anticyclonic gyre) were investigated over 2 d, using two day- and two night-samples per site. Zooplankton biomass was correlated to chlorophyll abundance, with lowest values in the oligotrophic Mediterranean water and highest in Atlantic water. The high biomass resulted from the enhancement of the secondary production, as indicated by the greater proportion of nauplii and the increase of zooplankton metabolism and feeding. Total... |
Tipo: Text |
Palavras-chave: Mer d’Alboran; Distribution; Front; Zooplancton; Alboran sea; Distribution; Front; Zooplankton. |
Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/00322/43348/42878.pdf |
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Gaudy, R; Youssara, F. |
Respiration, excretion (NH4 and PO4) and feeding of zooplankton from the upper 200 m of the Almeria-Oran frontal region (western Mediterranean), were studied during winter 1997. Eight sites belonging to the three main hydrodynamic structures of the area (Mediterranean water, geostrophic Atlantic jet and associated anticyclonic gyre) were considered. Lowest values of respiration, PO4 excretion, O/P atomic ratio and particle ingestion were found in Mediterranean waters. At the frontal limit, respiration and ammonium excretion were enhanced compared to the adjacent structures (Mediterranean water and Atlantic jet). In the gyre water, lowest O/N and highest N/P values were observed and maximum faecal pellet production and reproduction activity (inferred from... |
Tipo: Text |
Palavras-chave: Mer d'Alboran; Front; Zooplancton; Métabolisme; Nutrition; Alboran sea; Front; Zooplankton; Metabolism; Feeding. |
Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/00322/43275/43006.pdf |
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Registros recuperados: 10 | |
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