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| Registros recuperados: 30 | |
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| Agogue, Helene; Mallet, Clarisse; Orvain, Francis; De Crignis, Margot; Mornet, Francoise; Dupuy, Christine. |
| In intertidal mudflats, during low tide exposure, microphytobenthos (MPB) migrate vertically through the surface sediment and form, with the heterotrophic bacteria, a transient biofilm. Inside this biofilm, multiple interactions exist between MPB and bacteria. These micro-organisms secrete a wide range of extracellular polymeric substances (EPS), which are major components of the biofilm matrix. In this study, we used a tidal mesocosm experiment in order to decipher the interactions of the MPB-EPS-bacteria complex within the biofilm. We tried to determine if the EPS could control bacterial activities and/or production and/or richness according to the age of the biofilm and to the immersion/emersion period. The dynamics of biomasses of MPB and prokaryotes,... |
| Tipo: Text |
Palavras-chave: Muddy sediment; Microphytobenthos; Bacteria; Extracellular polymeric substances; Interactions; Mesocosm. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00181/29271/27682.pdf |
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| Perrot, Laurie; Gohin, Francis; Ruiz-pino, Diana; Lampert, Luis; Huret, Martin; Dessier, Aurelie; Malestroit, Pascale; Dupuy, Christine; Bourriau, Paul. |
| Coccolithophore blooms occur regularly from April to June in the Bay of Biscay where they have been observed for many years from ocean-colour imagery thanks to the ability of their calcite plates to scatter light. They are easily depicted on interpolated images of non-algal Suspended Particulate Matter (SPM) derived from satellite reflectance data in May, at the time of the PELGAS (PELagique GAScogne) annual surveys. Over the springs 2012 to 2015, the PELGAS surveys provided in-situ data on the turbidity throughout the water column and on the hydrological environment prevailing during the blooms in the vicinity of the continental shelf break. The satellite-derived SPM in the area of coccolithophore blooms was closely related to measured turbidity in the... |
| Tipo: Text |
Palavras-chave: Bay of Biscay; Ocean colour; Suspended particulate matter; Turbidity; Coccoliths; Stratification. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00416/52790/53689.pdf |
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| Degre, Delphine; Leguerrier, D; Du Chatelet, E; Rzeznik, J; Auguet, Jean-christophe; Dupuy, Christine; Marquis, E; Fichet, Denis; Struski, Caroline; Joyeux, E; Sauriau, Pierre-guy; Niquil, Nathalie. |
| Inverse analysis was used to model the food webs of two intertidal mudflat ecosystems: Aiguillon Cove (AC) and Brouage Mudflat (BM) (south-western Atlantic coast, France). The aim of the present study is to describe and compare the functioning of these two ecosystems. The method of inverse analysis has been adapted in order to take into account, in a single calculation, two seasons: spring/summer (mid-March to mid-October) and autumn/winter (the rest of the year). Gathering all available data on the two sites, the most important gaps in knowledge were identified with the help of sensitivity analyses: they concerned mainly the exports of material by grazing fish (such as mullet Liza ramada), resuspension of microphytobenthos, and fluxes linked to microfauna... |
| Tipo: Text |
Palavras-chave: Atlantic coast; Sensitivity analysis; Tidal flat; Inverse analysis; Steady state; Food web. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-1863.pdf |
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| Doray, Mathieu; Petitgas, Pierre; Romagnan, Jean-baptiste; Huret, Martin; Duhamel, Erwan; Dupuy, Christine; Spitz, Jérôme; Berger, Laurent; Dorémus, Ghislain; Bourriau, Paul; Grellier, Patrick; Massé, Jacques; Sanchez, Florence. |
| The initial objective of the PELGAS integrated survey was to assess the biomass of small pelagic fish in the Bay of Biscay in spring. Sampling has been extended to study the spatial structure and dynamics of the pelagic ecosystem in springtime. The PELGAS survey has produced since 2000 long-term time-series of spatially-explicit data and indices, describing the main pelagic ecosystem components: hydrology, phytoplankton, mesozooplankton, fish and megafauna. In addition to small pelagic fish biomass estimates used for fish stock assessment, the survey now delivers two types of ecosystem products: standard gridded maps of ecosystem parameters, and a time series dataset of indicators of the Bay of Biscay pelagic ecosystem state. The evolution of the PELGAS... |
| Tipo: Text |
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| Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00457/56844/58693.pdf |
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| Dupuy, Christine; Vaquer, André; Lam Hoai, Thong; Rougier, Claude; Mazouni, Nabila; Lautier, Jacques; Collos, Yves; Le Gall, Solange. |
| The Mediterranean Thau Lagoon is an important oyster farming area in Europe. Oyster growth rates are among the highest in France, although chlorophyll a concentration is low. Previous studies have demonstrated that picophytoplankton, nano-microphytoplankton, dinoflagellates and loricate ciliates such as tintinnids are abundant. However, heterotrophic flagellates and aloricate ciliates have not been investigated. The aim of this study was to assess picophytoplankton, protist and zooplankton abundances in the Lagoon and to investigate the particular structure of the microbial food web, which may explain such paradoxical oyster growth. In oligotrophic waters in the Thau Lagoon, the picoeukaryote Ostreococcus tauri is the dominant autotrophic picoplankter,... |
| Tipo: Text |
Palavras-chave: Trophic link; Picophytoplankton; Heterotrophic protist; Microbial food web; Thau Lagoon; Food source; Oyster; Bivalve. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/2000/publication-812.pdf |
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| Doray, Mathieu; Petitgas, Pierre; Romagnan, Jean-baptiste; Huret, Martin; Duhamel, Erwan; Dupuy, Christine; Spitz, Jérôme; Authier, Matthieu; Berger, Laurent; Doremus, Ghislain; Bourriau, Paul; Grellier, Patrick; Masse, Jacques; Sanchez, Florence. |
| The initial focus of the PELGAS integrated survey was to assess the small pelagic fish biomass in the Bay of Biscay in springtime, for fisheries management purposes. Sampling has been extended to produce long-term time-series of spatially-explicit data and indices, describing the main pelagic ecosystem components: hydrology, phytoplankton, mesozooplankton, fish and megafauna. A collaborative analysis of these datasets has brought new insights on the Bay of Biscay pelagic ecosystem summarized here. New results on single ecosystem components include an analysis of water samples to groundtruth the results of an ocean color algorithm aiming at detecting phytoplanktonic coccolithophores. New insights on mesozooplankton spatio-temporal distribution and energy... |
| Tipo: Text |
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| Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00445/55665/57331.pdf |
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| Loret, Pascale; Le Gall, Solange; Dupuy, Christine; Blanchot, Jean; Pastoureaud, Annie; Delesalle, Bruno; Caisey, Xavier; Jonquieres, Gerard. |
| Pearl oysters are farmed in oligotrophic tropical atoll lagoons where planktonic communities are dominated by production from cyanobacteria smaller than 2 pm. Paradoxically, the pearl oyster Pinctada margaritifera only retains particles larger than 2 Pm. In this study, we assess the relative contribution of hetero/mixotrophic microbiota to the available planktonic resource. In Takapoto Atoll, picocyanobacteria are the dominant biomass (20 mug C l(-1)). The carbon biomass of ciliates and dinoflagellates ranges from 1 to 24 and 0.5 to 5 mug C l(-1) respectively, with a mean of 6 mug C l(-1) for ciliates and 2 mug C l(-1) for dinoflagellates. The possible retention by P. margaritifera on a natural protist suspension was investigated. Due to its high clearance... |
| Tipo: Text |
Palavras-chave: Trophic resource; Picoplankton; Pinctada margaritifera; Pearl oysters; Atoll lagoon; Protists. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/2000/publication-823.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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| Dupuy, Christine; Pastoureaud, Annie; Ryckaert, Mireille; Sauriau, Pierre-guy; Montanie, Hélène. |
| To assess the in situ impact of oysters Crassostrea gigas on planktonic protist and bacteria communities and the potential contribution of protozoa to their food resource intake, the abundance and the diversity of protists and bacteria were followed in 2 Atlantic coastal ponds, with and without oysters. The protist biomass in such ponds was high, with a maximum in spring of 982 mug C l(-1) and a minimum in winter of 179 pg C l(-1). Whatever the season, the presence of oysters (20 m(-2) corresponding to an average of 23 mg dry weight m(-2)) induced a significant decrease in >5 pm protist abundance. On the contrary, planktonic organisms <5 pm, such as Chlorophyta flagellates and bacteria, developed similarly in both ponds. It can be assumed that such... |
| Tipo: Text |
Palavras-chave: Trophic link; Bacteria; Protists; Microbial food web; Coastal pond; Food source; Oysters; Bivalve. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/2000/publication-822.pdf |
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| Méléder, Vona; Savelli, Raphael; Barnett, Alexandre; Polsenaere, Pierre; Gernez, Pierre; Cugier, Philippe; Lerouxel, Astrid; Le Bris, Anthony; Dupuy, Christine; Le Fouest, Vincent; Lavaud, Johann. |
| The gross primary production (GPP) of intertidal mudflat microphytobenthos supports important ecosystem services such as shoreline stabilization and food production, and it contributes to blue carbon. However, monitoring microphytobenthos GPP over a long-term and large spatial scale is rendered difficult by its high temporal and spatial variability. To overcome this issue, we developed an algorithm to map microphytobenthos GPP in which the following are coupled: (i) NDVI maps derived from high spatial resolution satellite images (SPOT6 or Pléiades), estimating the horizontal distribution of the microphytobenthos biomass; (ii) emersion time, photosynthetically active radiation (PAR), and mud surface temperature simulated from the physical model MARS-3D;... |
| Tipo: Text |
Palavras-chave: Microphytobenthos; Intertidal mudflat; Gross primary production; Remote sensing; NDVI; Modeling. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00643/75531/76429.pdf |
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| Savelli, Raphael; Méléder, Vona; Cugier, Philippe; Polsenaere, Pierre; Dupuy, Christine; Lavaud, Johann; Barnett, Alexandre; Le Fouest, Vincent. |
| Microphytobenthos (MPB) at the sediment surface of intertidal mudflats are known to show a high spatial and temporal variability in response to the biotic and abiotic conditions prevailing at the mud surface. It makes long-term and large-scale monitoring of MPB Gross Primary Production (GPP) difficult to set up. In this study, we developed the first 3D physical-biological coupled model (MARS-3D) that explicitly simulates GPP of intertidal MPB at the mudflat scale, and we compared the outputs with in situ and space remote sensing MPB GPP data. We discuss the sources of discrepancies between the modeling and the remote sensing approach in the light of future developments to be done. For instance, the remote sensing algorithm provides a very synoptic view of... |
| Tipo: Text |
Palavras-chave: Microphytobenthos; Intertidal mudflat; Gross primary production; Remote sensing; Physical-biological modeling. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00654/76612/77764.pdf |
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| Pagano, Marc; Sagarra, Pascual-boi; Champalbert, Gisele; Bouvy, Marc; Dupuy, Christine; Thomas, Yoann; Charpy, Loic. |
| Metazooplankton abundance, biomass (<80 mu m, 200-500 mu m and >500 mu m) and community structure in the Ahe atoll were studied together with their relationships with environmental factors (temperature, salinity, wind) and trophic factors (phytoplankton, bacteria, heterotrophic nanoflagellates (HNF) and ciliates) during three periods in 2008-2009. Meroplankton, mainly bivalve and gastropod larvae, was dominant. Holoplankton was dominated by copepods, the main species being Oithona spp., Paracalanus parvus, Clausocalanus spp., Corycaeus spp., Acartia fossae and Undinula vulgaris. The results suggest a clear wind influence on the structure and horizontal distribution of the zooplankton communities. The metazooplankton appeared to be controlled mainly... |
| Tipo: Text |
Palavras-chave: Metazooplankton; Spatio-temporal patterns; Trophic relationships; Pearl oyster; Atoll lagoon; French Polynesia. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00101/21207/19419.pdf |
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| Joux, Fabien; Agogue, Helene; Obernosterer, Ingrid; Dupuy, Christine; Reinthaler, Thomas; Herndl, Gerhard J.; Lebaron, Philippe. |
| In an attempt to compare the microbial community structure between the sea surface microlayer (SML) and subsurface waters (SSW), we determined the enrichment factors (EF: the ratio of abundance or activity in the SML to abundance or activity in SSW) of 13 biological parameters. Samples were taken at 2 contrasting coastal sites in the Mediterranean Sea, corresponding to a high (Barcelona, Spain) and low (Banyuls-sur-Mer, France) urbanized area. Principal component analysis showed that temporal variability was much higher at Barcelona than at Banyuls, and that the characteristics of the SML and SSW samples were more closely related at Barcelona. At both sites, the SML was weakly enriched in heterotrophic bacteria (on average 1.1-fold), Synechococcus spp. (on... |
| Tipo: Text |
Palavras-chave: Sea surface microlayer; Enrichment factor; Microbial structure; Virus-like particles; Bacteria; Microalgae; Nanoflagellates. |
| Ano: 2006 |
URL: https://archimer.ifremer.fr/doc/00243/35434/33961.pdf |
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| Montanie, Helene; Ory, Pascaline; Orvain, Francis; Delmas, Daniel; Dupuy, Christine; Hartmann, Hans J.. |
| In shallow macrotidal ecosystems with large intertidal mudflats, the sediment-water coupling plays a crucial role in structuring the pelagic microbial food web functioning, since inorganic and organic matter and microbial components (viruses and microbes) of the microphytobenthic biofilm can be suspended toward the water column. Two experimental bioassays were conducted in March and July 2008 to investigate the importance of biofilm input for the pelagic Microbial and Viral Loops. Pelagic inocula (< 0.6 μ- and < 10 μ filtrates) were diluted either with < 30 kDa-ultrafiltered seawater or with this ultrafiltrate enriched with the respective size-fractionated benthic biofilm or with < 30 kDa-benthic compounds (BC). The kinetics of heterotrophic... |
| Tipo: Text |
Palavras-chave: Mudflats; Virus; Bacteria; HNF; Coastal water. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00166/27691/25883.pdf |
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| Doray, Mathieu; Petitgas, Pierre; Huret, Martin; Duhamel, Erwan; Romagnan, Jean-baptiste; Authier, Matthieu; Dupuy, Christine; Spitz, Jerome. |
| This paper is a practical contribution to two important debates raised by the implementation of marine ecosystem based management: (i) which ecosystem data can be provided by a fisheries survey optimised for ecosystem monitoring; and (ii) how to combine/select potential indicators to derive useful information on marine ecosystem status and dynamics? A suite of 143 potential indicators, including spatial indices, representing small pelagic fish and their biotic and abiotic environments are presented. Indicators were routinely derived from the PELGAS integrated ecosystem survey conducted in spring in the Bay of Biscay (BoB). The general patterns over time in this suite of 5–16 years, non-stationary time series are characterised using a methodology based on... |
| Tipo: Text |
Palavras-chave: Min/max autocorrelation factors; Time correlation; Survey-based indicators; Marine Strategy Framework Directive; Ecosystem variability; Bay of Biscay; Pelagic ecosystem. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00414/52552/53443.pdf |
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| Savelli, Raphael; Dupuy, Christine; Barille, Laurent; Lerouxel, Astrid; Guizien, Katell; Philippe, Anne; Bocher, Pierrick; Polsenaere, Pierre; Le Fouest, Vincent. |
| Microphytobenthos (MPB) from intertidal mudflats are key primary producers at the land–ocean interface. MPB can be more productive than phytoplankton and sustain both benthic and pelagic higher trophic levels. The objective of this study is to assess the contribution of light, mud temperature, and gastropod Peringia ulvae grazing pressure in shaping the seasonal MPB dynamics on the Brouage mudflat (NW France). We use a physical–biological coupled model applied to the sediment first centimetre for the year 2008. The simulated data compare to observations, including time-coincident remotely sensed and in situ data. The model suggests an MPB annual cycle characterised by a main spring bloom, a biomass depression in summer, and a moderate fall bloom. In early... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00471/58226/60732.pdf |
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| Bouvy, Marc; Dupuy, Christine; Got, Patrice; Domaizon, Isabelle; Carré, Claire; Pagano, Marc; Debroas, Didier; Roques, Cécile; Leboulanger, Christophe. |
| Planktonic communities from Juan de Nova lagoon were submitted to a single exposure of diuron or naphthalene in triplicate outdoor 40-L mesocosms for 5 days. The study followed the temporal changes of the assemblages by determining abundances and taxonomic level of microbial (heterotrophic prokaryotes, picocyanobacteria, heterotrophic protists and phytoplankton) and metazooplankton communities. Exposure to both contaminants did not result in significant changes in phytoplankton abundances. Microscopic identification demonstrated the dominance of Bacillariophyta (mostly Chaetoceros tenuissimus) accounting for more than 95% of the microalgae detected in all mesocosms. Using 18S rRNA metabarcoding, temporal changes in the proportion of eukaryotic operational... |
| Tipo: Text |
Palavras-chave: Contaminant; Taxonomy; Metabarcoding; Plankton; Experiments; Lagoon.. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00681/79348/81853.pdf |
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| Dupuy, Christine. |
| L'huître Crassostrea gigas se nourrit en filtrant le phytoplancton, mais dans les marais atlantiques, cette production phytoplanctonique ne suffit pas pour équilibrer son bilan énergétique. L'analyse du réseau microbien planctonique au cours de l'isolement du marais en mortes-eaux montre une succession de peuplements : des diatomées qui épuisent rapidement les nutriments, puis des bactéries et enfin des protistes flagellés et ciliés. La production bactérienne représente une ressource énergétique importante, mais l'huître ne peut capter efficacement ces particules < 1 µm. Les protistes hétéro/mixotrophes qui se nourrissent de ces picoproies pourraient alors, s' ils sont retenus par l'huître, représenter un "relais trophique" entre la production... |
| Tipo: Text |
Palavras-chave: Huître; Ressources trophiques; Réseau microbien; Protistes; Lien trophique; Marais maritime. |
| Ano: 1999 |
URL: http://archimer.ifremer.fr/doc/00439/55103/56549.pdf |
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| Registros recuperados: 30 | |
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