Consulta: subjectFacets:"Hydrobia ulvae"
Registros recuperados: 7
Data/hora: 11/06/2024 10:54:15

Influence of environment factors on bacterial ingestion rate of the deposit-feeder Hydrobia ulvae and comparison with meiofauna
Provedor de dados: 5
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

Devenir des bactéries dans les réseaux trophiques des vasières intertidales : le cas de brouage (Baie de Marennes-Oléron)
Provedor de dados: 5
Autores: Pascal, Pierre-yves.
Bacteria are highly abundant and productive in intertidal mudflat sediments. By analogy  with pelagic system, it has been suggested that bacteria play an important role in benthic food  web. Due to technical difficulties, numbers of studies dealing with benthic bacterivory are not  numerous and give conflicting results. A method using community of 15N enriched bacteria as  tracer was developed in order to measure grazing of meiofauna and macrofauna. Since enriched  bacteria present characteristics of size, activity and diversity close to natural ones, bias due to  selective bacterial ingestion by grazers are limited. Due to tidal cycles, intertidal mudflat  constitutes highly variable environment at short time scale. Since those variations may influence...
Tipo: Text
Palavras-chave: Stable isotope; Hydrobia ulvae; Foraminifera; Copepod; Nematode; Bacteria; Mudflat; Trophic foodweb; Isotope stable; Hydrobia ulvae; Foraminifère; Copépode; Nématode; Bactérie; Vasière; Réseau trophique.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/these-4778.pdf

Spatio-temporal variations in intertidal mudflat erodability: Marennes-Oleron Bay, western France
Provedor de dados: 5
Autores: Orvain, Francis; Sauriau, Pierre-guy; Le Hir, Pierre; Guillou, Gael; Cann, Philippe; Paillard, Michel.
A portable erosion device (ERIS) was deployed in November 2000 and May 2001 to investigate the spatio-temporal variation of fine-grained sediment erosion over a transect on the intertidal mudflats of Marennes-Oleron Bay, western France. The objective was to relate changes in bed erodability over diurnal emersion periods to bioturbation, rapid changes in sediment characteristics, and microphytobenthos biomass.   Macrofaunal assemblages were dominated by the bivalve, Scrobicularia plana, on the upper mudflat, and by the gastropod, Hydrobia ulvae. on the middle mudflat. A power relationship was obtained where tau(cr) was plotted as a function of sediment density. Results from the upper part of the mudflat deviated from this relationship due to bioturbation by...
Tipo: Text
Palavras-chave: EPS; Microphytobenthos; Erodability; Intertidal mudflat; Sediment; Scrobicularia plana; Hydrobia ulvae; Bioturbation; Resuspension; Eris.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-3779.pdf

Environmental and behavioural factors affecting activity in the intertidal gastropod Hydrobia ulvae
Provedor de dados: 5
Autores: Orvain, Francis; Sauriau, Pierre-guy.
Laboratory microcosms were used to investigate the mud snail Hydrobia ulvac (Pennant) bioturbation activities and behavioural changes in response to snail density, algal food, sediment moisture content, light regime and water cover conditions. Density-dependent kinetics of bioturbated muddy areas were described by von Bertalanffy equations, which provided reliable estimates of mud surface covering rates by snail tracks (m(2) h(-1) snail(-1)), Snails need a wet habitat to be active either covered by seawater or by moving in fluid layers for low-tide conditions. Light and microphytobenthic biomass, which are less potent to affect snail activity, are positively interrelated to increase covering rates in the tested chl a concentrations within the range of 1 -...
Tipo: Text
Palavras-chave: Modelling; Intertidal mudflat; Hydrobia ulvae; Environmental factors; Bioturbation; Behaviour.
Ano: 2002
URL: http://archimer.ifremer.fr/doc/2002/publication-3775.pdf

Kinetics of tidal resuspension of microbiota: Testing the effects of sediment cohesiveness and bioturbation using flume experiments
Provedor de dados: 5
Autores: Blanchard, Gérard F; Sauriau, Pg; Cariou-le Gall, Valerie; Gouleau, D; Garet, Mj; Olivier, F.
Resuspension of the top few sediment layers of tidal mud flats is known to enhance planktonic biomass of microbiota (benthic diatoms and bacteria). This process is mainly controlled by tidal shear stress and cohesiveness of mud, and is also influenced by bioturbation activities. Laboratory experiments in a race track flume were performed to test the interactive effects of these factors on both the critical entrainment and resuspension kinetics of microbiota from silt-clay sediments from the Marennes-Oleron Bay, France. The marine snail Hydrobia ulvae was used to mimic surface bioturbation activities. As expected, the kinetics of microbial resuspension versus shear stress were largely controlled by the cohesiveness of silt-clay sediments. However, our...
Tipo: Text
Palavras-chave: Microphytobenthos; Bacteria; Resuspension; Bioturbation; Hydrobia ulvae; Shear velocity; Sediment cohesiveness; Flume experiment.
Ano: 1997
URL: http://archimer.ifremer.fr/doc/00337/44789/44480.pdf

The influence of sediment cohesiveness on bioturbation effects due to Hydrobia ulvae on the initial erosion of intertidal sediments: A study combining flume and model approaches
Provedor de dados: 5
Autores: Orvain, F; Sauriau, Pierre-guy; Bacher, Cedric; Prineau, Michel.
Laboratory experiments performed in a recirculating flume were designed to quantify the bioturbation influence of the mud snail Hydrobia ulvae, one of the most abundant deposit feeders on European intertidal mudflats. Variations in sediment moisture content that occur between bedforms in shore-normal, ridge and runnel systems of intertidal mudflats were added to the model definition. Sediment erosion thresholds, erosion rates and the microalgal pigment composition of resuspended material were quantified for different H. ulvae densities (0, 1000, 5000, 10 000 and 50 000 snails m(-2)) and applied bed shear stresses. Two different sediment moisture contents were tested. In the absence of macrofauna, recorded turbidities increased up to the maximum applied...
Tipo: Text
Palavras-chave: Model; Flume; Chloropigments; Ridges and tunnels; Mudflat; Sediment; Hydrobia ulvae; Bioturbation; Resuspension.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/publication-3774.pdf

Interacting effects of Hydrobia ulvae bioturbation and microphytobenthos on the erodibility of mudflat sediments
Provedor de dados: 5
Autores: Orvain, Francis; Sauriau, Pierre-guy; Sygut, A; Joassard, Lucette; Le Hir, Pierre.
Microphytobenthos-macrofauna sediment interactions and their effects on sediment erodability were examined in laboratory experiments. Sediment beds were manipulated in a tidal mesocosm to produce diatom mats in exponential or in stationary phases of development after 6, 8 or 11 d of culture. These sediment beds were used in flume experiments to investigate the influence of bioturbation by the gastropod Hydrobia ulvae on both sediment and pigment resuspension as a function of the physiological state of the microphytobenthic mats. In most experiments, only a surface layer was resuspended. A model was used to analyse in detail the contribution of each variable to this surface-layer erosion. Bioturbation was the major factor controlling resuspension, and its...
Tipo: Text
Palavras-chave: Sediment; Bioturbation; Erosion; Model; Hydrobia ulvae; Physiological state; Microphytobenthos; Resuspension.
Ano: 2004
URL: http://archimer.ifremer.fr/doc/2004/publication-3780.pdf