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| Registros recuperados: 22 | |
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| Orvain, Francis; Le Hir, Pierre; Sauriau, Pierre-guy. |
| Previous studies have shown that the gastropod Hydrobia ulvae destabilizes the top layers of fine-grained sediments. This process is mediated by the formation of a "biogenic" fluff layer that includes tracks, faecal pellets and mucus. This fluff layer has been shown to be easily resuspended before general bed erosion. In order to examine how fluff layer and bed. erosion interact, flume experiments were performed with fluid sediments of varying water contents. Ten thousand snails were placed and allowed to crawl for 5 h on the sediment surface, and then the resuspended sediment mass was measured in response to step-wise shear stress increases. Two distinct erosion phases were observed: (1) initial resuspension of the fluff layer and (2) the subsequent bed... |
| Tipo: Text |
Palavras-chave: Gastropoda; Erosion sediment; Bioturbation; Cohesive sediment; Marine sediment. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/2003/publication-805.pdf |
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| Orvain, Francis. |
| Flume experiments were designed to study how sediment erodibility was modified by the facultative suspension-feeder Scrobicularia plana living at different densities in sediment beds of various degrees of compaction. Two separate erosion phases were identified from the resuspension kinetics: (1) erosion of an unconsolidated surficial layer (i.e. fluff layer) and (2) the subsequent bed erosion. S. plana were found to influence both erosion phases: (1) erosion rates of the fluff layer were controlled by bioturbation activities, the extents of which were influenced by bivalve density and the degree of compaction of the sediments, and (2) critical thresholds of the subsequent bed erosion decreased as clam density increased, likely due to depressions in the... |
| Tipo: Text |
Palavras-chave: Resuspension; Model; Functional groups; Sediment transport; Bioturbation; Scrobicularia plana; Intertidal mudflat. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-3776.pdf |
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| Donnadieu, Y; Lecroart, P; Anschutz, P; Bertrand, P. |
| We have constructed a nonsteady state numerical model of organic carbon, aluminum, and uranium burial to examine the dynamic response of sediments to variations on thousand years scale. The three components are defined by distinct behaviors in the sedimentary system. The aluminum is a conservative component, the organic carbon is a nonconservative component degraded in superficial sediment, and the uranium is a component affected by redox conditions. By introducing a simultaneous variation of incoming fluxes of C-org and Al, geochemical profiles of Al, Corg, and U clearly show separate distributions after burial. Each component record the synchronous variation of the incoming fluxes, but the position in the sedimentary pile of the recording differs from a... |
| Tipo: Text |
Palavras-chave: Time lag; Sedimentary system; High-resolution record; Modeling; Bioturbation. |
| Ano: 2002 |
URL: https://archimer.ifremer.fr/doc/00223/33390/31872.pdf |
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| Aschenbroich, Adelaide; Michaud, Emma; Stieglitz, Thomas; Fromard, Francois; Gardel, Antoine; Tavares, Marcos; Thouzeau, Gerard. |
| This study in French Guiana evaluates the changes of crab assemblages and their bioturbation activities between mangrove early stages (pioneer and young mangrove) and within stages by taking their spatial heterogeneity (tidal channels, flat areas, pools) into account. The results show differences in crab assemblage structure between and within the early stages of mangrove in relation to microhabitat and sediment characteristics. The sediment reworking rates are a function of the biomass or density of particular species (Ucides cordatus, Uca cumulanta) and burrower functional groups. Crab species or functional interaction mediate changes in sediment reworking rates suggesting the need to consider entire benthic communities rather than single species. This... |
| Tipo: Text |
Palavras-chave: Mangroves; Crabs; Community composition; Bioturbation; French Guiana; Amazon. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00350/46154/45852.pdf |
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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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| Mathieu, M; Leflaive, J; Ten Hage, L; De Wit, R; Buffan Dubau, E. |
| The aim of the present study was to examine the effects of biofilm-dwelling nematode activity on the oxygen turnover of cultured diatom biofilms. Oxygen microprofiles were simultaneously measured using the microelectrode technique in biofilms incubated with and without nematodes during short-term (24 h) and medium-term (6 d) experiments. During 24 h nycthemeral incubations, maximum oxygen concentrations and oxygen peak depths of microprofiles, as well as net oxygen production rates, were significantly higher in the diatom biofilms with nematodes. These effects might be dependent on the densities of nematodes. In the present study, significant effects were observed at nematode densities exceeding 100 ind. cm(-2), but not at a density <50 ind. cm(-2).... |
| Tipo: Text |
Palavras-chave: Bioturbation; Grazing; Net production rate; Oxygen community metabolism; Microelectrode; Oxygen microprofile; Nematodes; Diatom biofilms. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3607.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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| Feuillet-girard, Michelle; Gouleau, Dominique; Blanchard, Gérard; Joassard, Lucette. |
| Fluxes of nutrients (NH sub(4) super(+), NO sub(3) super(-), PO sub(4) super(3-) and Si(OH) sub(4)) were studied on an intertidal mudflat in Marennes-Oleron Bay, France, at two different seasons and at different times of the emersion period. Fluxes through the sediment-water interface were both calculated from vertical profiles of nutrient concentration in pore-water (diffusive fluxes, JD) and measured in light and dark benthic mini-chambers (measured fluxes, J sub(0)). Results indicate that ammonia was mainly released in summer while nitrate was mainly taken up in late winter. This uptake from the overlying water was probably due to the coupling of nitrification-denitrification within the sediment. The J sub(0) /J sub(D) ratio further indicates that... |
| Tipo: Text |
Palavras-chave: Estran vaseux; Flux de nutriments; Microphytobenthos; Bioturbation; Marennes-Oléron; Intertidal mudflat; Nutrient fluxes; Microphytobenthos; Bioturbation; Marennes-Oleron Bay. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00038/14893/12220.pdf |
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| Reichardt, W. |
| The predominantly anoxic, sulfide-rich sandy sediment of a shallow lagoon at Kiel Fjord was densely inhabited by the polychaete worm Nereis diversicolor (280 cm super(3) m super(-2) of biomass volume). Burrow walls which contrasted by their brown coloration of at least 1.5 mm thickness with the bulk of the reduced black sediment, made up for 6% of the total volume of the 10 cm cores investigated. Only the uppermost mm of the internal surface layer contained detectable O sub(2). As a result of the build up of internal redox gradients, CO sub(2) dark fixation was activated in the burrow walls (by a factor of approximately equals 2). Assays of ribulose-biphosphate carboxylase activities and viable counts of potentially chemoautotrophic bacteria in different... |
| Tipo: Text |
Palavras-chave: Nereis diversicolor; Polychaeta; Bacteria; Microorganisms; Carbon cycle; Tube dwellers; Carbon fixation; Burrows; Bioturbation; Sediments. |
| Ano: 1984 |
URL: http://archimer.ifremer.fr/doc/1984/acte-990.pdf |
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| Lemonnier, Hugues; Hochard, Sebastien; Nakagawa, Kento; Courties, Claude; Rodier, Martine. |
| We conducted a mesocosm study to investigate the combined effect of organic enrichment and sediment resuspension by shrimp on phytoplankton communities in shrimp aquaculture ponds. Hence, the factorial design included two factors, i.e., (i) shrimp density with a concomitant increase of feed input resulting in organic enrichment and (ii) with/without access of shrimp to the sediments. Increasing feed input in the system raised the eutrophication state of the environment characterized by an increase in phytoplankton biomass. Bioturbation enhanced (i) mineralization of organic matter via the microbial loop, resulting in faster nutrient recycling, (ii) an increase of primary production, and (iii) buffering capacity against eutrophication consequences. The... |
| Tipo: Text |
Palavras-chave: Aquaculture; Litopenaeus stylirostris; Phytoplankton communities; Eutrophication; Bioturbation. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00392/50364/51066.pdf |
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| Lamarque, Bastien; Deflandre, Bruno; Galindo Dalto, Adriana; Schmidt, Sabine; Romero-ramirez, Alicia; Garabetian, Frédéric; Dubosq, Nicolas; Diaz, Melanie; Grasso, Florent; Sottolichio, Aldo; Bernard, Guillaume; Gillet, Hervé; Cordier, Marie-ange; Poirier, Dominique; Lebleu, Pascal; Derriennic, Hervé; Danilo, Martin; Murilo Barboza Tenório, Márcio; Grémare, Antoine. |
| The spatial distributions of (1) surface sediment characteristics (D0.5, Sediment Surface Area (SSA), Particulate Organic Carbon (POC), Chlorophyll-a (Chl-a), Phaeophytin-a (Phaeo-a), Total and Enzymatically Hydrolyzable Amino Acids (THAA, EHAA), δ13C) and (2) sediment profile image (apparent Redox Potential Discontinuity (aRPD), numbers and depths of biological traces) characteristics were quantified based on the sampling of 32 stations located within the West Gironde Mud Patch (Bay of Biscay, NE Atlantic) in view of (1) assessing the spatial structuration of a temperate river-dominated ocean margin located in a high-energy area, (2) disentangling the impacts of hydrodynamics and bottom trawling on this structuration, and (3) comparing the West Gironde... |
| Tipo: Text |
Palavras-chave: RiOMar; Surface sediment; Spatial distribution; Sedimentary organics; Bioturbation. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00681/79336/81848.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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| Hochard, Sébastien; Royer, Florence; Hubert, Morgane; Lemonnier, Hugues. |
| The evolution of benthic pelagic coupling was followed in two semi-intensive shrimp ponds in New Caledonia, with a special emphasis on the role of microphytobenthos (MPB). Three distinct periods could be identified. During the first period, MPB activity led to relative decoupling between the water column and the sediment, both compartments being autotrophic with low nutrients exchanges. During the second period, the sediment operated at the edge of a functional switch between autotrophy and heterotrophy. The amplitude of nutrient fluxes depended of the pool considered (DIN, DIP) and showed light dark variation. In the last period, sediment switched to heterotrophy with the establishment of benthic-pelagic coupling concomitantly to a massive sediment... |
| Tipo: Text |
Palavras-chave: Tropical aquaculture; Shrimp; Eutrophication; Benthic-pelagic coupling; Microphytobenthos; Bioturbation. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00485/59681/62754.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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| Registros recuperados: 22 | |
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