Consulta: creatorFacets:"Richard, P"
Registros recuperados: 12
Data/hora: 09/06/2024 02:16:59

Influence of environment factors on bacterial ingestion rate of the deposit-feeder Hydrobia ulvae and comparison with meiofauna
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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

Stable isotope analysis position of intertidal of food source and trophic nematodes and copepods
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Rzeznik Orignac, J; Boucher, G; Fichet, Denis; Richard, P.
Four dominant nematode species and various copepods from an intertidal mudflat in Marennes-Oleron Bay were analyzed for delta C-13 and delta N-15 ratios together with their potential food source, the microphytobenthos. It was shown that microphytobenthic C is passed to nematodes either by grazing or predation on herbivorous meiofauna by other nematodes. Diatoms of different sizes exhibited different C-13 content, which can be reflected in herbivorous meiofauna, such as the nematodes Daptonema oxycerca and Metachromadora remanei and the bulk of copepods, indicating they can select different sizes of diatoms. Results confirm the need to analyze meiofauna feeding habits at the species or genera level since the delta N-15 and delta C-13 signatures differed...
Tipo: Text
Palavras-chave: Stable isotopes; Marennes Oleron; Mudflat; Food web; Benthic diatoms; Microphytobenthos; Meiofauna; Copepods; Nematodes.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-4292.pdf

Coupling experimental and field-based approaches to decipher carbon sources in the shell of the great scallop, Pecten maximus (L.)
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Marchais, V.; Richard, J.; Jolivet, A.; Flye-sainte-marie, J.; Thebault, J.; Jean, F.; Richard, P; Paulet, Y. -m.; Clavier, J.; Chauvaud, L.
This research investigated how the carbon isotopic composition of food source (delta C-13(food)) and dissolved inorganic carbon (delta C-13(DIC)) influences the carbon isotopic composition of Pecten maximus shells (delta C-13(shell)) under both experimental and natural conditions. The objectives are to better understand the relationship between P. maximus and its environment, and to specifically distinguish conditions under which calcification is influenced by respired CO2 derived from food sources versus conditions in which calcification uses inorganic carbon from seawater. Laboratory experiment investigated carbon incorporation into shell carbonates by maintaining scallops under conditions where the stable carbon isotopic composition of food sources was...
Tipo: Text
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00284/39485/82772.pdf

Bacterivory in the common foraminifer Ammonia tepida: Isotope tracer experiment and the controlling factors
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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

Effect of starvation on RNA, DNA and protein-content of laboratory-reared larvae and juveniles of Solea-solea
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Richard, P; Bergeron, Jean-pierre; Boulhic, M; Galois, Robert; Person, Jeanine.
Using analyses of individuals, dry weight, RNA, DNA and protein content were measured on the same samples to assess the nutritional status of laboratory-reared larvae and juveniles of Solea solea (L.). During the early life of S. solea, 2 growth periods could be distinguished by dry weight measurements and biochemical composition analysis. After metamorphosis, dry weight, RNA, DNA and protein content per individual increased more slowly than before metamorphosis. RNA, DNA and protein were strongly positively correlated to dry weight of fed larvae. Starvation led to immediate loss of weight and to decrease in RNA and protein content, while DNA amount per individual remained roughly constant. Percentage of protein relative to dry weight was always lower in...
Tipo: Text
Ano: 1991
URL: http://archimer.ifremer.fr/doc/00072/18304/15868.pdf

Variations des caractéristiques pondérales et des compositions amino-acide et protéique pendant le développement embryonnaire de Palaemon serratus
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Richard, P; Ceccaldi, H.j.
Wet and dry weights variations related to mother shrimps length, as well as free amino acids, proteins and lipoproteins concentrations of the eggs, have been measured during embryonic development. Eggs wet weight strongly increases whereas dry weight remains nearly constant. Both are closely correlated to mother shrimp length. Total free amino acids concentration is fourfold higher at hatching than at laying, due to the increase of some amino acids such as proline, glycine, alanine and glutamic acid, whereas the so-called essential ones decrease in percentage, chiefly the tryptophane ratio. The slight fall of the total protein concentration throughout the development is the result of embryonic proteins synthesis from lipoproteins. Aminoaaid composition of...
Tipo: Text
Ano: 1977
URL: http://archimer.ifremer.fr/doc/00305/41608/40817.pdf

Etude de la composition corporelle de la sole (Solea solea ) au cours du jeune: Influence de la temperature
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Richard, P; Djabali, M; Lagardere, Francoise; Lagardere, J.
The effects of starvation on Solea solea at 10 and 20 degree C in sea water, were studied. At 20 degree C fishes start to die on week 4; at 10 degree C they support a longer starvation period (9 weeks). Proximate analysis shows that protein are more steadily used at 20 degree C than at 10 degree C, contrarily to the corporal lipids which are used at the same rate. Starvation results in a reduction of liver lipids and glycogen. This reduction is more pronounced at 20 degree C : 70% of hepatic glycogen is used at this temperature within the first week of starvation against 30% at 10 degree C.
Tipo: Text
Palavras-chave: Solea solea; Soleidae; Pisces; Survival; Tissues; Biochemical composition; Temperature effects; Proteins; Lipids; Starvation; Metabolism.
Ano: 1983
URL: http://archimer.ifremer.fr/doc/1983/acte-1246.pdf

Food source of intertidal nematodes in the Bay of Marennes-Oleron (France), as determined by dual stable isotope analysis
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Riera, P; Richard, P; Gremare, A; Blanchard, G.
Nematodes living on an intertidal mudflat of the Marennes-Oleron Bay (France) were assayed for delta(13)C and delta(15)N ratios together with their potential food resources between July 1992 and May 1993. Results suggest that nematodes do not exploit all the components of the sedimented organic matter (SOM) pool at the same rate. Furthermore, based on coefficients of average trophic enrichment found in the literature for both C and N, the enrichment of nematodes in C-13 and their depletion in N-15 relative to SOM suggest that microphytobenthos constitutes their main food source in this particular environment.
Tipo: Text
Palavras-chave: Nematodes; Microphytobenthos; Food sources; Stable isotope ratios.
Ano: 1996
URL: http://archimer.ifremer.fr/doc/00282/39288/43132.pdf

Bacterivory by benthic organisms in sediment : Quantification using 15N-enriched bacteria
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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 &amp;#956;m3) 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

Dynamics of spatial patterns of microphytobenthic biomass: inferences from a geostatistical analysis of two comprehensive surveys in Marennes-Oleron bay (France)
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Guarini, Jean-marc; Blanchard, Fabian; Bacher, Cedric; Gros, Philippe; Riera, P; Richard, P; Gouleau, D; Galois, R; Prou, Jean; Sauriau, Pg.
Microphytobenthos plays an important role as primary producer in shallow embayments subject to a tidal regime. The present paper aims to characterize the spatial patterns of sedimentary chlorophyll a (chl a) biomass in 2 seasons in the wide intertidal mudflats of the Marennes-Oleron Bay (France); furthermore, it provides estimates of total microphytobenthic biomass. Accordingly, a systematic sampling scheme was performed in June 1995 and in January 1996. On average, biomass was higher in June (ca 120 mg chi a m(-2)) than in January (ca 85 mg chi a m(-2)). Moreover, the geostatistical analysis revealed that spatial similarities were propagated over larger distances in June (6 km) than in January (2.2 km). In order to account or this result, we suggest that...
Tipo: Text
Palavras-chave: Microphytobenthos; Chlorophyll a; Spatial distribution; Geostatistics; Intertidal mudflat.
Ano: 1998
URL: http://archimer.ifremer.fr/doc/00447/55852/58117.pdf

Bacterivory of a mudflat nematode community under different environmental conditions
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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

Comparative foraging ecology and ecological niche of a superabundant tropical seabird: the sooty tern Sterna fuscata in the southwest Indian Ocean
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Jaquemet, S; Potier, M; Cherel, Y; Kojadinovic, J; Bustamante, Paco; Richard, P; Catry, T; Ramos, J; Le Corre, M.
Over 6-million pairs of sooty terns Sterna fuscata breed once a year in the southwest Indian Ocean, mostly on three islands of the Mozambique Channel (Europa, Juan de Nova and Glorieuses) and in the Seychelles region. Seasonal reproduction in either winter or summer is the dominant strategy in the area, but non-seasonal reproduction also occurred in some places like at Glorieuses Archipelago. The feeding ecology of the sooty tern was investigated during the breeding seasons to determine whether terns showed significant differences in their trophic ecology between locations. Regurgitations were analyzed to describe the diet of individuals when breeding, and stable isotopes and mercury concentrations were used to temporally integrate over the medium-term of...
Tipo: Text
Palavras-chave: Mercury &amp;#948; 15N &amp;#948; 13C fish larvae flying squid feeding ecology Seabirds.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-4654.pdf