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| 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 |
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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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| 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 |
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| 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 |
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| 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 |
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