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| Pascal, P.y.; Dupuy, C; Mallet, C; Richard, P; Niquil, N. |
| The fate of benthic bacterial biomass in benthic food webs is a topic of major importance but poorly described. This paper describes an alternative method for evaluation of bacterial grazing rate by meiofauna and macrofauna using bacteria pre-enriched with stable isotopes. Natural bacteria from the sediment of an intertidal mudflat were cultured in a liquid medium enriched with 15NH4Cl. Cultured bacteria contained 2.9% of 15N and were enriched sufficiently to be used as tracers during grazing experiments. Cultured bacteria presented a biovolume (0.21 μm3) and a percentage of actively respiring bacteria (10%) similar to those found in natural communities. The number of Operational Taxon Units found in cultures fluctuated between 56 and 75% of that... |
| Tipo: Text |
Palavras-chave: Tracer; Stable isotope; Sediment; Grazing; Bacteria. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4296.pdf |
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| Pascal, P.y.; Dupuy, C; Richard, P; Niquil, N. |
| The majority of sediment dweller foraminifera are deposit feeders. They use their pseudopodia to gather sediment with associated algae, organic detritus and bacteria. Uptake of bacteria by foraminifera have been observed but rarely quantified. We measured uptake of bacteria by the common foraminifera Ammonia tepida using 15N pre-enriched bacteria as tracers. In intertidal flats, seasonal, tidal and circadian cycles induce strong variations in environmental parameters. Grazing experiments were performed in order to measure effects of abiotic (temperature, salinity and irradiance) and biotic (bacterial and algal abundances) factors on uptake rates of bacteria. In mean conditions, A. tepida grazed 78 pgC ind-1 h-1 during the first eight hours of incubation,... |
| Tipo: Text |
Palavras-chave: Trophoecology; Prey abundance; Mudflat; Grazing; Foraminifera; Environmental factor; Bacteria. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4298.pdf |
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| Pascal, P.y.; Dupuy, C; Richard, P; Rzeznik-orignac, J; Niquil, Nathalie. |
| The fate of the benthic bacterial biomass is a topic of major importance in understanding how softbottom environments function. Because of their high abundance, production and nutritional value, benthic bacteria may constitute an important food resource for benthic fauna. The trophic role of bacteria for a nematode community on the Brouage mudflat (Marennes-Ole´ron-France), dominated by three species: Chromadora macrolaima (64% of the abundance), Daptonema oxycerca (15%) and Ptycholaimellus jacobi (8%), was determined in grazing experiments using 15N pre-enriched bacteria. On intertidal flats, seasonal, tidal and circadian cycles induce strong variations in environmental conditions. Grazing experiments were performed in order to measure the effects of... |
| Tipo: Text |
Palavras-chave: Mudflat; Environmental factor; Grazing; Bacteria; Nematode. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4295.pdf |
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| Pascal, Pierre-yves; Dupuy, C; Richard, P; Haubois, A.g.; Niquil, N. |
| Deposit feeders are able to process a considerable volume of sediment, containing large quantities of associated bacteria. However, conclusions concerning the trophic role played by benthic bacteria in marine sediments are still not fully elucidated. This study deals with bacterivory by the gastropod Hydrobia ulvae, one of the most abundant deposit-feeding species in intertidal mudflats in Western Europe. Ingestion rates of bacteria were determined during grazing experiments using 15N preenriched bacteria. Grazing experiments were performed in order to measure effects of abiotic (temperature, salinity and luminosity) and biotic (bacterial and algal abundances) factors on ingestion rates of bacteria by H. ulvae of an intertidal mudflat (Brouage,... |
| Tipo: Text |
Palavras-chave: Mudflat; Nematodes; Ammonia tepida; Environmental factors; Grazing; Bacteria; Gastropod; Hydrobia ulvae; Deposit feeding. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4781.pdf |
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