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| Registros recuperados: 38 | |
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| Giraldo, Carolina; Ernande, Bruno; Cresson, Pierre; Kopp, Dorothee; Cachera, Marie; Travers-trolet, Morgane; Lefebvre, Sebastien. |
| Depth is one of the environmental variables influencing the structure of marine food webs by directly or indirectly influencing benthic-pelagic coupling and predator-prey relationships. In shallow waters, the high degree of connectivity between pelagic and benthic networks results in complex systems with multiple interactions. Digestive tract (DT) and stable isotope (SI) analyses were used to investigate depth-related changes in feeding patterns for 33 fish species (eastern English Channel [EEC]) collected between 5 m and 80 m depth. Fish species were first arranged into functional groups based upon trophic and habitat similarities. DTs were used to determine the general topology of the food web and SIs were used to estimate the contributions of different... |
| Tipo: Text |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00386/49711/52255.pdf |
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| Cachera, Marie; Ernande, Bruno; Villanueva, Ching-maria; Baheux, Mickael; Lefebvre, Sebastien. |
| By covering 80% of Earth, the global ocean is the most spread ecosystem in the world. Human activities (pollution, fisheries…) have huge impacts on both oceans and marine life. Despites overfishing and intense maritime transport, many fish species remain in the English Channel. A major challenge in biological research is to comprehend and facilitate the emergence of body shape in fishes for understanding how these organisms may respond and persist in complex and multiple environments with predictable and unpredictable perturbations. Body shape in fish is conditioned by several developmental paths and functions depending on multitude behaviours. Fishes body morphology varies in every species and in some cases had been shown to influence their occurrence,... |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00161/27217/25416.pdf |
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| Ropert, Michel; Lefebvre, Sebastien; Soletchnik, Patrick; Blin, J. L.; Faury, Nicole; Struski, Caroline. |
| The "trophic risk" has been demonstrated in the bioenergetic model developed in vivo and based on various diet conditions similar to those of different types of oyster culture basins (eutrophic, heterotrophic and oligotrophic) [22, 23]. The trophic resource mortality relationship differs from one basin to another, according to the quantity of this resource. Multy-varied analysis (ACP) conducted on a total of 11 oyster culture sites and handled in a database matching mortality and environmental data, show that the trophic indicator "chlorophyll a" (often coupled with temperature) is involved in a positive correlation with the mortality of both age classes (1 and 2 years old). The stock transfer from the Bay of Veys to the west coast of Cotentin in spring... |
| Tipo: Text |
Palavras-chave: MOREST; Crassostrea gigas; Physiologie; Phéopigments; Ressources trophiques; Modèle bioénergétique; Mortalités; Huîtres. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/acte-3410.pdf |
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| Chambord, Sophie; Villanueva, Ching-maria; Ernande, Bruno; Lefebvre, Sebastien. |
| Les réseaux trophiques engendrent tous les transferts d’énergies et de matières au sein d’un écosystème, ce qui expliquent l’intérêt de leur compréhension. Ces réseaux dépendent essentiellement des relations proies-prédateurs, il est donc important de connaître les processus les déterminants. La morphométrie peut être un processus déterminants les relations proies-prédateurs. Ces travaux ont permis d’identifier les relations entre les caractéristiques morphologiques des individus et leur régime alimentaire chez deux espèces relativement contrastée en termes de guilde trophique, à savoir Pleuronectes platessa (plie, Linné 1758) et Dicentrarchus labrax (bar commun, Linné 1758). |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00143/25417/23568.pdf |
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| Hussenot, Jerome; Lefebvre, Sebastien; Martin, Jean-louis. |
| Fish culture (seabass, turbot...) on the French metropolitan coast, and shrimp culture in the overseas territories (essentially New Caledonia and Tahiti) are subject to a regular development through land based farms. Three thematic of research on aquaculture ponds are carried out in CREMA-L’Houmeau, in collaboration with producers. The aim of the first one is to determine the optimal rearing conditions (stocking density, water renewal rate, input of oxygen, rate of feeding...) which allow to minimise the quantity of wastes for a similar final biomass. The second part aims to reduce the nutrient loading in the effluent, through open-air treatments: sedimentation ponds, foam fractionation, mass production of phytoplankton, and rearing of molluscs on the... |
| Tipo: Text |
Palavras-chave: Fish; Shrimp; Pond management; Effluents; Treatment. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/00016/12728/9650.pdf |
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| Callier, Myriam; Lefebvre, Sebastien; Dunagan, Mary K.; Bataille, Marie-paule; Coughlan, Jennifer; Crowe, Tasman P.. |
| The extent of the influence of salmon farming on the environment and on the uptake of particulate and dissolved effluents by benthic organisms was assessed using community structure and stable isotope analyses. Sediment cores were collected in 2 directions: perpendicular and parallel to the main residual current, 0, 25 and 200 m from 2 salmon farms (Millstone and Cranford) located in Mulroy Bay, Ireland. In addition, artificial substrates were placed for 2 mo at 1 m depth 0, 25 and 200 m from one farm to trace the uptake of farm-related nutrients by fouling organisms. The extent of measurable change in benthic communities (abundance, diversity, structure, trophic composition) depended on residual current direction. Intraspecific variation in isotopic... |
| Tipo: Text |
Palavras-chave: Aquaculture; Organic matter; Stable isotope; Community structure; Diet shift; Trophic structure. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00144/25481/23634.pdf |
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| De Cubber, Lola; Lefebvre, Sebastien; Fisseau, Charline; Cornille, Vincent; Gaudron, Sylvie Marylene. |
| Arenicola spp. are marine benthic polychaetes dug for bait by anglers. Without regulation, this activity can lead to the decrease of lugworms' population meanwhile affecting the physical characteristics of the beach and the biodiversity. Here, we identified through morphology and genetics two species of lugworms, Arenicola marina and A. defodiens, within a Marine Protected Area of the Eastern English Channel (France). For each species, abundance and spatial distribution were assessed using a stratified random sampling and interpolation at four studied sites, as well as some life-history traits. These data were compared to lugworms' collection data to estimate its sustainability and to provide potential management measures. At one site, A. marina was... |
| Tipo: Text |
Palavras-chave: Arenicola marina; Arenicola defodiens; Spawning; Population structure; Size at first maturity; Recreational fisheries; Conservation; English channel. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00451/56284/60474.pdf |
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| Kopp, Dorothee; Lefebvre, Sebastien; Villanueva, Ching-maria; Ernande, Bruno. |
| The structure, dynamics and productivity of marine ecosystems depend mainly on their underlying food webs. In temperate marine ecosystems, specifically in the English Channel, strong seasonality, habitat diversity and variability in the sources of available organic matters are controlling factors affecting the trophodynamics of these networks. Exploitation through fisheries may also alter these food webs. During the last decade, the study of trophic ecology has greatly benefited from the use of stable isotope analysis (SIA) that integrates diet information over long time periods and complements gut content analysis. Applied in complex ecosystems, such as the English Channel, SIA may help to detect nutrient pathways and trophic links. Stable isotopic... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00161/27213/25412.pdf |
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| Chouvelon, Tiphaine; Chappuis, A.; Bustamante, Paco; Lefebvre, Sebastien; Mornet, Francoise; Guillou, G.; Violamer, L.; Dupuy, Christine. |
| European sardine (Sardina pilchardus) and European anchovy (Engraulis encrasicolus) are two species of economical and ecological significance in the Bay of Biscay (north-east Atlantic). However, the trophic ecology of both species is still poorly known in the area, and more generally, few studies have considered the potential trophic overlap between sardines and anchovies worldwide. This study aims to highlight the trophic links between the mesozooplankton and adults of these two pelagic fish in the Bay of Biscay, through carbon and nitrogen stable isotope analysis (SIA). Mesozooplankton and individuals of sardines and anchovies were collected during one season (spring 2010), over spatially contrasted stations within the study area. First, the potential... |
| Tipo: Text |
Palavras-chave: Plankton preservation; Plankton delipidation; Pelagic fish; Trophic interactions; Spatial variability; Isotopic mixing model. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00176/28741/27280.pdf |
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| Buzin, Florence; Dupuy, Beatrice; Lefebvre, Sebastien; Barille, Laurent; Haure, Joel. |
| In response to the closure of shellfish production sites due to increasing occurrence of toxic algal blooms, land-based recirculating aquaculture systems (RAS) could be used by producers to store a proportion of their stock temporarily. An RAS prototype was tested in this study to store Pacific oyster Crassostrea gigas over a range of temperatures. In such systems, the water temperature is a variable that could influence the bivalve excretion rate of ammonia, the concentration of which may become critical for the water quality. In this study, we first estimated the total ammonia nitrogen (TAN, N-NH4+ + N-NH3) excretion of the Pacific oyster and then investigated whether the bacterial population associated with the oysters could act as a natural biofilter... |
| Tipo: Text |
Palavras-chave: Crassostrea gigas; Ammonia excretion; Nitrification rate; Recirculating system; Temperature. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00248/35889/34409.pdf |
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| Emmery, Antoine; Lefebvre, Sebastien; Alunno-bruscia, Marianne; Kooijman, S. A. L. M.. |
| We studied the dynamics of stable isotopes δ13C and δ15N of an opportunistic suspension feeder the Pacific oyster (Crassostrea gigas) to better understand the factors that influence the trophic enrichment (trophic-shift, Δ) between primary producers and consumers. Most of the previous studies on this topic do not quantify mass fluxes or isotopic discrimination phenomena in the organism, which are two pillars in isotope ecology. We used a dynamic energy budget (DEB) approach (Kooijman, 2010) to quantify i) the fluxes of elements and isotopes in C. gigas soft tissues and ii) the impact of the scaled feeding level, the organism mass and the isotopic ratio of food on the "trophic-shift" Δ, and isotope turnover in tissues. Calibration and parametrization... |
| Tipo: Text |
Palavras-chave: Oyster; Isotopic ratio; Discrimination; Trophic-shift; Diet; DEB theory. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00043/15434/12784.pdf |
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| Fagon, N.; Le Souchu, Pierrick; Lefebvre, Sebastien; Pouvreau, Stephane. |
| Force est de constater que, malgré un intérêt croissant depuis les 20 dernières années en matière d'écophysiologie des mollusques, il n'existe, à notre connaissance, aucun système réellement adapté à la mesure en continu et de façon concomitante des principales fonctions écophysiologies des mollusques filtreurs (notamment consommation et filtration). Faisant suite à la réalisation d'un cahier des charges et d'une version préliminaire d'un système, le but du présent projet est de doter la Station Expérimentale d'Argenton (entité expérimentale de l'UMR « Physiologie et Ecophysiologie des Mollusques Marins) de deux systèmes automatisés et opérationnels de mesures de l'écophysiologie des mollusques filtreurs. Après un bref rappel des principes de mesures des... |
| Tipo: Text |
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| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/00306/41769/40982.pdf |
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| Orvain, Francis; Lefebvre, Sebastien; Montepini, J.; Sebire, M.; Gangnery, Aline; Sylvand, B.. |
| Intertidal flats of the estuarine macro-intertidal Baie des Veys (France) were investigated to identify spatial features of sediment and microphytobenthos (MPB) in April 2003. Gradients occurred within the domain, and patches were identified close to vegetated areas or within the oyster-farming areas where calm physical conditions and biodeposition altered the sediment and MPB landscapes. Spatial patterns of chl a content were explained primarily by the influence of sediment features, while bed elevation and compaction brought only minor insights into MPB distribution regulation. The smaller size of MPB patches compared to silt patches revealed the interplay between physical structure defining the sediment landscape, the biotic patches that they contain,... |
| Tipo: Text |
Palavras-chave: Benthic diatoms; Benthos; Coastal ecosystems; Intertidal flats; Baie des Veys; Normandie; Spatial pattern; Geostatistics; Kriging. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00088/19945/17598.pdf |
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| Cresson, Pierre; Travers-trolet, Morgane; Rouquette, Manuel; Timmerman, Charles-andre; Giraldo, Carolina; Lefebvre, Sebastien; Ernande, Bruno. |
| Whether considered as a risk for human health or as ecological tracers, contaminants' concentrations measured in fish muscles are commonly expressed relative to wet or dry mass. Comparison of results required conversion factors (CF) but accurate values are scarce and case-specific. The present paper is aimed at investigating errors linked with the use of the theoretical value. Muscles dry and wet masses were measured in 15 fish species to determine the actual CF. Most CF were lower than the theoretical wet:dry ratio of 5 classically used, with variations at individual and species level. Muscle lipid content (inferred by C/N ratios) was a crucial factor explaining discrepancies, claiming for caution when working with lipid-rich species. The observed... |
| Tipo: Text |
Palavras-chave: Wet:dry ratio; Conversion factor; Contaminant concentration; Marine fish; Percentage of humidity. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00396/50736/51456.pdf |
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| Kopp, Dorothee; Lefebvre, Sebastien; Cachera, Marie; Villanueva, Maria Ching; Ernande, Bruno. |
| Recent theoretical considerations have highlighted the importance of the pelagic-benthic coupling in marine food webs. In continental shelf seas, it was hypothesized that the trophic network structure may change along an inshore-offshore gradient due to weakening of the pelagic-benthic coupling from coastal to offshore areas. We tested this assumption empirically using the eastern English Channel (EEC) as a case study. We sampled organisms from particulate organic matter to predatory fishes and used baseline-corrected carbon and nitrogen stable isotope ratios (δ13C and δ15N) to determine their trophic position. First, hierarchical clustering on δ13C and δ15N coupled to bootstrapping and estimates of the relative contribution of pelagic and benthic carbon... |
| Tipo: Text |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00226/33765/32191.pdf |
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| Ubertini, Martin; Lefebvre, Sebastien; Gangnery, Aline; Grangere, Karine; Le Gendre, Romain; Orvain, Francis. |
| The high degree of physical factors in intertidal estuarine ecosystem increases material processing between benthic and pelagic compartments. In these ecosystems, microphytobenthos resuspension is a major phenomenon since its contribution to higher trophic levels can be highly significant. Understanding the sediment and associated microphytobenthos resuspension and its fate in the water column is indispensable for measuring the food available to benthic and pelagic food webs. To identify and hierarchize the physical/biological factors potentially involved in MPB resuspension, the entire intertidal area and surrounding water column of an estuarine ecosystem, the Bay des Veys, was sampled during ebb tide. A wide range of physical parameters (hydrodynamic... |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00090/20126/17775.pdf |
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| Registros recuperados: 38 | |
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