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| Registros recuperados: 21 | |
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| Roussel, Erwan; Sauvadet, Anne Laure; Allard, Jonathan; Chaduteau, Carine; Richard, Pierre; Cambon Bonavita, Marie-anne; Chaumillon, Eric. |
| In Marennes-Oleron Bay, a macro-tidal bay located on the French Atlantic coast, kilometer-scale acoustic turbidity reveals an accumulation of free gas in the sediment. Large concentrations of organic matter and rapid sedimentation rates provide ideal settings for biogenic methane cycling. We integrate seismic, sedimentologic, biogeochemical and molecular genetic approaches to determine whether microbial methane cycling is involved in this process. Here we show that the acoustic turbidity upper boundary matched with X-ray facies displaying fissures with the highest methane concentrations, demonstrating the existence of methane bubbles in the sediment. 16S rRNA and mcrA gene clone libraries were dominated by sequences affiliated to the three known ANME... |
| Tipo: Text |
Palavras-chave: Sediment; Methane; McrA; 16S rRNA; Archaea. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6165.pdf |
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| Lebreton, Benoit; Richard, Pierre; Radenac, Gilles; Bordes, Monique; Breret, Martine; Arnaud, Christophe; Mornet, Francoise; Blanchard, Gerard F.. |
| The role of epiphytes in an intertidal Zostera noltii seagrass bed in Marennes-Oleron Bay was assessed in comparison with the other main benthic primary producers (Z. noltii, microphytobenthos) at two bathymetric levels and on a seasonal basis. Assemblage and biomass of epiphytes were studied using scanning electron microscopy (SEM). Z noltii and its detrital matter followed a typical seasonal pattern: microphytobenthos was present in large quantities throughout the year representing 21% of the total biomass while detrital matter, above-ground parts and below-ground parts accounted for 65, 9 and 5%, respectively. Only two species of epiphytic diatoms, Cocconeis scutellum and Cocconeis placentula, were observed on seagrass leaves. Epiphyte biomass was very... |
| Tipo: Text |
Palavras-chave: SEM; Cocconeis spp.; Epiphyte diatom; Microphytobenthos; Zostera noltii; Intertidal seagrass bed; Primary producer. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6589.pdf |
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| Herlory, Olivier; Blanchard, G; Planche, S; Huet, V; Richard, Pierre. |
| Many scientists consider that the top centimetre of the sediment on intertidal mudflats contains the photosynthetic competent biomass (PCB). Part of this biomass migrates upward to the surface of the sediment during diurnal emersion periods to form a temporary biofilm: the photosynthetic active biomass (PAB). The present study tests the hypothesis that the size of the biofilm (PAB) is functionally dependent on PCB. Therefore, we have plotted PAB as a function of PCB for a range of different environmental conditions: 3 seasons and 5 tidal situations, representing a total of 600 cores. This investigation points out that, in spring and autumn, there was a simple linear relationship between PAB and PCB, thus indicating that the maximum size of the biofilm... |
| Tipo: Text |
Palavras-chave: Functional relationship; Biofilm; Biomass; Intertidal mudflat; Microphytobenthos. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-3622.pdf |
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| Lienart, Camilla; Savoye, Nicolas; Bozec, Yann; Breton, Elsa; Conan, Pascal; David, Valerie; Feunteun, Eric; Grangere, Karine; Kerherve, Philippe; Lebreton, Benoit; Lefebvre, Sebastien; L'Helguen, Stephane; Mousseau, Laure; Raimbault, Patrick; Richard, Pierre; Riera, Pascal; Sauriau, Pierre-guy; Schaal, Gauthier; Aubert, Fabien; Aubin, Sebastien; Bichon, Sabrina; Boinet, Christophe; Bourasseau, Line; Breret, Martine; Caparros, Jocelyne; Cariou, Thierry; Charlier, Karine; Claquin, Pascal; Cornille, Vincent; Corre, Anne-marie; Costes, Laurence; Crispi, Olivier; Crouvoisier, Muriel; Czamanski, Marie; Del Amo, Yolanda; Derriennic, Herve; Dindinaud, Francois; Durozieri, Maia; Hanquiez, Vincent; Nowaczyk, Antoine; Devesa, Jeremy; Ferreira, Sophie; Fornier, Michel; Garcia, Fabrice; Garcia, Nicole; Geslin, Sandrine; Grossteffan, Emilie; Gueux, Aurore; Guillaudeau, Julien; Guillou, Gael; Joly, Orianne; Lachaussee, Nicolas; Lafont, Michel; Lamoureux, Jezabel; Lecuyer, Eric; Lehodey, Jean-paul; Lemeille, David; Leroux, Cedric; Mace, Eric; Maria, Eric; Pineau, Philippe; Petit, Franck; Pujo-pay, Mireille; Rimelin-maury, Peggy; Sultan, Emmanuelle. |
| In coastal systems, the multiplicity of sources fueling the pool of particulate organic matter (POM) leads to divergent estimations of POM composition. Eleven systems (two littoral systems, eight embayments and semi-enclosed systems and one estuary) distributed along the three maritime façades of France were studied for two to eight years in order to quantify the relative contribution of organic matter sources to the surface-water POM pool in coastal systems. This study was based on carbon and nitrogen elemental and isotopic ratios, used for running mixing models. The POM of the estuary is dominated by terrestrial material (93% on average), whereas the POM of the other systems is dominated by phytoplankton (84% on average). Nevertheless, for the latter... |
| Tipo: Text |
Palavras-chave: Particulate organic matter; Coastal systems; C and N stable isotopes; C:N ratio; Mixing model. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00374/48550/48871.pdf |
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| Guarini, Jean-marc; Blanchard, Gerard; Bacher, Cedric; Gros, Philippe; Riera, Pascal; Richard, Pierre; Gouleau, Dominique; Galois, Robert; Prou, Jean; Sauriau, Pierre-guy. |
| 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 chl a m-2) than in January (ca 85 mg chl 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 for this result , we suggest that... |
| Tipo: Text |
Palavras-chave: Marennes Oleron; Intertidal mudflat; Geostatistics; Spatial distribution; Chrlorophyll a; Microphytobenthos. |
| Ano: 1998 |
URL: https://archimer.ifremer.fr/doc/1998/publication-3820.pdf |
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| Richard, Pierre. |
| Ce rapport présente les résultats des travaux réalisés dans le cadre du programme d'étude "Potentialités conchylicoles du Pertuis Breton" pour mettre en évidence, par traçage isotopique naturel, les sources de nourriture utilisées par les mollusques cultivés (moules et huîtres). Les 13 sites étudiés s'étendaient sur le littoral de la Baie de l'Aiguillon, du sud des côtes vendéennes (moules sur bouchots) et de la côte Nord-Est de l'Ile de Ré (huîtres sur table), et comprenaient aussi 2 stations au milieu du Pertuis Breton (moules sur filières) . Les sources potentielles de nourriture présentes dans le Pertuis ont d'abord été caractérisées pour leur composition isotopique, et trois campagnes de prélèvement pour analyse isotopique des mollusques ont été... |
| Tipo: Text |
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| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/00426/53782/54684.pdf |
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| Niquil, Nathalie; Kerleguer, G; Leguerrier, D; Richard, Pierre; Legrand, Helene; Dupuy, Christine; Pascal, P; Bacher, Cedric. |
| The presence of herbicides in the run-off water coming over Brouage mudflat (Marennes-Oleron Bay, France) is suspected to cause a loss of primary production by benthic diatom biofilm. Microphytobenthos being the main primary producer of this ecosystem, it was questioned about what could be the effect of such a modification of primary production on the entire food web that depends on it. The probable impacts were investigated through a sensitivity analysis conducted on the steady-state model of the Brouage mudflat, coupling two seasons and trophic-hydrodynamic flows. The loss of benthic primary production had an effect on compartments at a low trophic level, but was buffered at higher levels because of the compensation of herbivory by other pathways and... |
| Tipo: Text |
Palavras-chave: Intertidal mudflat food web; Pollution; Microphytobenthos; Inverse analysis; Sensitivity analysis. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-3613.pdf |
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| Legrand, Helene; Herlory, Olivier; Guarini, Jean-marc; Blanchard, Gerard; Richard, Pierre. |
| Atrazine and diuron are two herbicides present in sediments of the intertidal mudflats in the Pertuis Charentais (Atlantic coast, France). They may negatively affect photosynthesis processes in microphytobenthos, the most productive primary producer in these environments. The impact of these herbicides on benthic diatoms was investigated using PAM fluorimetry on natural microalgal communities, once extracted from sediment, by following the variations of the effective quantum yield of PSII (Phi(PSII)) during exposure to atrazine and diuron concentrations in a range 0.1 mu g L-1 (.) 10 mg L-1. No significant effect was noticed for 0.1 mu g L-1 concentrations, but progressive reduction in photosynthetic efficiency, always occurring within 15 min, was... |
| Tipo: Text |
Palavras-chave: Diuron; Atrazine; PAM; Chlorophyll fluorescence; Microphytobenthos. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-3614.pdf |
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| Raimonet, Melanie; Guillou, Gael; Mornet, Francoise; Richard, Pierre. |
| Although nitrogen stable isotope ratio (delta N-15) in macroalgae is widely used as a bioindicator of anthropogenic nitrogen inputs to the coastal zone, recent studies suggest the possible role of macroalgae metabolism in delta N-15 variability. Simultaneous determinations of delta N-15 of dissolved inorganic nitrogen (DIN) along the land sea continuum, inter-species variability of delta N-15 and its sensitivity to environmental factors are necessary to confirm the efficiency of macroalgae delta N-15 in monitoring nitrogen origin in mixed-use watersheds. In this study, delta N-15 of annual and perennial macroalgae (Ulva sp., Enterommpha sp., Fucus vesiculosus and Fucus serratus) are compared to delta N-15-DIN along the Charente Estuary, after... |
| Tipo: Text |
Palavras-chave: Nitrogen isotopes; Nitrate; Ammonium; Primary producers; Indicators; Land-sea continuum. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00134/24558/23645.pdf |
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| Herlory, Olivier; Richard, Pierre; Blanchard, Gerard. |
| The light response curve methodology for microphytobenthic biofilms was studied by comparing the two most usual approaches used in pulse amplitude modulated (PAM) fluorometry. The non-sequential light curve (N-SLC) method is characterized by independent measures of the photosynthetic activity across a light gradient whereas the rapid light curve (RLC) method consists of successive measures on the same sample exposed to a stepwise increase of light intensities. Experiments were carried out on experimental microphytobenthic biofilms prepared from natural assemblages and acclimated to dark conditions. In preliminary experiments, N-SLCs were constructed from fluorescence induction curves performed at 12 different photon flux densities (PFDs). A minimum of 50 s... |
| Tipo: Text |
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| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3331.pdf |
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| Herlory, Olivier; Guarini, Jean-marc; Richard, Pierre; Blanchard, Gerard. |
| The spatio-temporal dynamics of the microphytobenthic biofilm was analysed at microscale over a complete day-time emersion period in an intertidal mudflat. The structures of the biofilm were monitored by analysing the variability of the epipelic diatom cover in the horizontal dimension and the kinetics of biomass dispersion in the vertical dimension. Colonisation of the sediment surface by diatoms was rapid (within 15 min); 75% of the biomass contained in the top 1 mm was concentrated in the upper 200 mum, but the cover never reached 100%. This biomass had a higher chlorophyll a/pheopigment ratio than deeper in the sediment, suggesting a better physiological state and a higher photosynthetic potential. The dynamics of the biomass in the upper 200 mum... |
| Tipo: Text |
Palavras-chave: Microphytobenthos; Biofilm; Intertidal mudflat; Spatio temporal dynamics; Microscale. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/00000/10905/7580.pdf |
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| Richard, Pierre; Blanchard, Gerard; Goulletquer, Philippe. |
| The trophic resources of cultivated mussel have! been characterized and their contribution to the food of these molluscs estimated in the Bay of Aiguillon (France) through the analysis of their natural C and N isotope composition. The contribution of terrestrial organic matter (δ(13)C = -27 to -34 %0) to mussel food resources is around 10% along the year, except in winter (15 10 30 %). A large seasonal variation is observed in the utilization of oceanic phytoplanktoll (δ(13)C = -19 to -21.5 %0) and of littoral benthic productions (microphytobenthos and phanerogame detritus,δ(13)C = -12.0 to -16.7 %0). Overall, the main food source of mussels is formed by benthic productions for molluscs grown on poles, in peculiar in the South of... |
| Tipo: Text |
Palavras-chave: Détritus; Production primaire; Isotope stable; Source trophique; Moule. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/2000/publication-2774.pdf |
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| Blanchard, Gerard F.; Guarini, Jean-marc; Richard, Pierre; Gros, Philippe; Mornet, Francoise. |
| A mathematical expression is proposed to describe the relationship between the photosynthetic capacity (Pmax) of natural assemblages of motile benthic diatoms and temperature. Experiments were performed in 2 different seasons to document the response of Pmax to a rapid increase in temperature (3*C h-1). In both cases, there was a progressive increase in Pmax up to an optimum temperature (Topt), beyond which Pmax declined rapidly. Topt did not change from September to December 1995, but the maximum photosynthetic capacity (PMAX, i.e. Pmax at Topt) was twice as high in September as in December. |
| Tipo: Text |
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| Ano: 1996 |
URL: http://archimer.ifremer.fr/doc/00013/12397/9183.pdf |
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| Cherel, Y; Le Corre, M; Jaquemet, S; Menard, Frederic; Richard, Pierre; Weimerskirch, H. |
| Characteristics of the tropical oceanic environment (low productivity, little seasonality) and poor diversity of tropical seabird foraging methods and prey relative to temperate and polar species suggest that tropical seabirds overall encompass a narrow range of isotopic niches, with large overlaps among species. To test this hypothesis, we examined the stable carbon (delta C-13) and nitrogen (delta N-15) isotopic composition of blood and feathers of 5 seabird species from Europa Island, Mozambique Channel. While differences were small, blood delta C-13 and delta N-15 values characterized 5 distinct and non-overlapping trophic niches during the breeding period. Seabirds used 2 distinct foraging areas (delta C-13), one used by sooty tern Sterna fuscata and... |
| Tipo: Text |
Palavras-chave: Trophic segregation; Tuna; Sooty tern; Pelagic ecosystem; Frigatebird; Booby. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4675.pdf |
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| Haubois, Anne-gaelle; Guarini, Jean-marc; Richard, Pierre; Blanchard, Gerard; Sauriau, Pierre-guy. |
| Spatio-temporal changes in density, breeding cycle, growth and population structure of Hydrobia ulvae (Gastropoda: Prosobranchia) were studied by monthly sampling of a wide bare mudflat in Marennes-Oleron Bay. Four stations, located along a cross-shore transect and characterized by different geomorphological structures, were investigated from March 2000 to February 2001. Hydrobia ulvae was mainly distributed in the upper half part of the mudflat and no individuals were found in the lower part. The breeding cycle extended from March to December and showed two annual peaks, in spring and in autumn. Three cohorts were recruited during the year and showed high growth rates during summer; the parameters of the von Bertalanffy model describing the growth curves... |
| Tipo: Text |
Palavras-chave: Gastropoda; Mudflat; Spatio temporal change; Population dynamic. |
| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/2002/publication-598.pdf |
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| Lebreton, Benoit; Richard, Pierre; Galois, Robert; Radenac, Gilles; Pfleger, Camille; Guillou, Gael; Mornet, Francoise; Blanchard, Gerard F.. |
| A current predominant paradigm emphasizes the role of epiphytic algae for invertebrates in most seagrass food webs. However, in some intertidal Zostera noltii beds, epiphyte biomass is very low compared to microphytobenthos and seagrass biomasses. We assessed the role of microphytobenthos in a temperate intertidal Z. noltii bed by combining stable isotope and fatty acid (FA) analyses on primary producers, composite sources suspended particulate organic matter (SPOM) and sediment surface organic matter (SSOM) and the main macrofaunal consumers. Z. noltii showed high delta C-13 (-9.9 parts per thousand) and high 18:2(n-6) and 18:3(n-3) contents. Microphytobenthos was slightly more C-13-depleted (-15.4 parts per thousand) and had high levels of diatom... |
| Tipo: Text |
Palavras-chave: Food web; Intertidal seagrass bed; Microphytobenthos; Zostera noltii; Stable isotope ratio; Fatty acid profiles; European Atlantic coast. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00035/14640/12051.pdf |
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| Registros recuperados: 21 | |
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