Consulta: creatorFacets:"Dupuy, Christine"
Registros recuperados: 30
Data/hora: 05/06/2024 04:30:01

Metazooplankton communities in the Ahe atoll lagoon (Tuamotu Archipelago, French Polynesia): Spatiotemporal variations and trophic relationships
Provedor de dados: 5
Autores: Pagano, Marc; Sagarra, Pascual-boi; Champalbert, Gisele; Bouvy, Marc; Dupuy, Christine; Thomas, Yoann; Charpy, Loic.
Metazooplankton abundance, biomass (&lt;80 mu m, 200-500 mu m and &gt;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

Small pelagic fish feeding patterns in relation to food resource variability: an isotopic investigation for Sardina pilchardus and Engraulis encrasicolus from the Bay of Biscay (north-east Atlantic)
Provedor de dados: 5
Autores: Chouvelon, Tiphaine; Violamer, L.; Dessier, Aurelie; Bustamante, Paco; Mornet, Francoise; Pignon-mussaud, Cecilia; Dupuy, Christine.
Small pelagic fish represent an essential link between lower and upper trophic levels in marine pelagic ecosystems and often support important fisheries. In the Bay of Biscay in the north-east Atlantic, no obvious controlling factors have yet been described that explain observed fluctuations in European sardine Sardina pilchardus and European anchovy Engraulis encrasicolus stocks, in contrast to other systems. The aim of this study was therefore to investigate to which extent these fluctuations could be trophodynamically mediated. The trophic ecology of both fish species was characterised over three contrasting periods (spring 2010 and 2011 and autumn 2011) in the area, in relation to potential variation in the abundance and composition of the...
Tipo: Text
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00247/35859/34381.pdf

Bacterial Dynamics in a Microphytobenthic Biofilm: a Tidal Mesocosm Approach
Provedor de dados: 5
Autores: 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

Mapping the Intertidal Microphytobenthos Gross Primary Production, Part II: Merging Remote Sensing and Physical-Biological Coupled Modeling
Provedor de dados: 5
Autores: 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

Subtidal Microphytobenthos: A Secret Garden Stimulated by the Engineer Species Crepidula fornicata
Provedor de dados: 5
Autores: Androuin, Thibault; Polerecky, Lubos; Decottignies, Priscilla; Dubois, Stanislas; Dupuy, Christine; Hubas, Cedric; Jesus, Bruno; Le Gall, Erwan; Marzloff, Martin; Carlier, Antoine.
The slipper limpet Crepidula fornicata is an emblematic invasive species along the northeast Atlantic coast. This gregarious gastropod lives in stacks of several individuals and forms extended beds in shallow subtidal areas. The effects of this engineer species on the colonized habitat can be physical (e.g., presence of hard-shell substrates with uneven topography) or biological (e.g., nutrient enrichment by direct excretion or via biodeposition). We hypothesized that through biological activity, nutrient fluxes at the sediment-water interface are enhanced, leading to stimulated primary productivity by microphytobenthos (MPB) associated with Crepidula beds. To test this fertilization hypothesis, we conducted a 10-day mesocosm experiment using C. fornicata...
Tipo: Text
Palavras-chave: Crepidula fornicata; Engineer species; Subtidal microphytobenthos; Fertilization; Hyperspectral imaging.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00472/58338/60893.pdf

Trophic relationships between metazooplankton communities and their plankton food sources in the Iles Eparses (Western Indian Ocean)
Provedor de dados: 5
Autores: Dupuy, Christine; Pagano, Marc; Got, Patrice; Domaizon, Isabelle; Chappuis, Alexis; Marchessaux, Guillaume; Bouvy, Marc.
Coral reef and atoll lagoons are among the most diversified marine ecosystems but also the most affected by the combined effects of climate change and human activities. The Iles Eparses (Scattered Islands) in the Western Indian Ocean have been little affected by human pressure and can be considered to be “pristine” ecosystems. Metazooplankton plays a major role in the functioning and productivity of aquatic ecosystems, and this study was undertaken: (i) to determine the spatial abundance, distribution and species composition of metazooplankton, (ii) to assess the effect of metazooplankton grazing on pico- and nanophytoplankton and (iii) to analyze the trophic positions of metazooplankton by using the stable isotope signatures of a wide variety of taxa and...
Tipo: Text
Palavras-chave: Metazooplankton; Spatial distribution; Grazing effect; Feeding ecology; Iles Eparses; Mayotte.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00317/42850/42259.pdf

Data products for fish stocks and ecosystem assessment:the PELGAS survey example
Provedor de dados: 5
Autores: 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
Ano: 2018
URL: http://archimer.ifremer.fr/doc/00457/56844/58693.pdf

Coccolith-derived turbidity and hydrological conditions in May in the Bay of Biscay
Provedor de dados: 5
Autores: 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

How would the loss of production due to an herbicide have repercussions in the food web of an intertidal mudflat? Sensitivity analysis of an inverse model for Brouage mudflat, Marennes-Oleron Bay, France
Provedor de dados: 5
Autores: 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

Feeding rate of the oyster Crassostrea gigas in a natural planktonic community of the Mediterranean Thau Lagoon
Provedor de dados: 5
Autores: 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

There's no harm in having too much: A comprehensive toolbox of methods in trophic ecology
Provedor de dados: 5
Autores: Majdi, Nabil; Hette-tronquart, Nicolas; Auclair, Etienne; Bec, Alexandre; Chouvelon, Tiphaine; Cognie, Bruno; Danger, Michael; Decottignies, Priscilla; Dessier, Aurélie; Desvilettes, Christian; Dubois, Stanislas; Dupuy, Christine; Fritsch, Clémentine; Gaucherel, Cédric; Hedde, Mickaël; Jabot, Franck; Lefebvre, Sebastien; Marzloff, Martin; Pey, Benjamin; Peyrard, Nathalie; Powolny, Thibaut; Sabbadin, Régis; Thébault, Elisa; Perga, Marie-elodie.
Trophic ecology is the study of feeding interactions and food acquisition by organisms. It includes the causes and consequences of those behaviours at all levels of biological organisation. As a field of research, it crosses many disciplinary boundaries and provides knowledge that is pertinent to many other areas of ecology. Here we list and categorise the methods available to trophic ecologists whose toolbox has broadened considerably in recent years. They encompass empirical and numerical approaches with focus ranging from molecules to ecosystems. We further examine the relationship of each method to features such as the scale of observation (from microbes to largest organisms) and organisational level (from individuals to ecosystems) as well as the...
Tipo: Text
Palavras-chave: Food web; Feeding interactions; Flux of energy; Computer simulations; Trophic models.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00487/59834/65986.pdf

Variability of energy density among mesozooplankton community: new insights in functional diversity to forage fish
Provedor de dados: 5
Autores: Dessier, Aurelie; Dupuy, Christine; Kerric, Anais; Mornet, Francoise; Authier, Matthieu; Bustamante, Paco; Spitz, Jerome.
To explore some aspects of mesozooplankton functional diversity, this study quantified energy density during the springtime in the Bay of Biscay both between different species and between different size-classes. Energy densities of copepod species (Centropages typicus, Anomalocera patersoni, Calanus helgolandicus, and Labidocera wollastoni), as well as anchovy eggs (Engraulis encrasicolus) ranged from 0.5 to 6.7 kJ/g wet weight (ww). Considering size-classes, energy densities varied from 0.74 to 1.26 kJ/g ww. Energy density of C. helgolandicus exhibited a spatial pattern with the highest values in the plume of the Gironde estuary. In contrast, no spatial pattern of energy density has been detected considering size-classes. Our results showed that the...
Tipo: Text
Palavras-chave: Bay of Biscay; Profitability; Copepods; Prey-predator relationship; Fisheries.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00407/51835/52434.pdf

Monitoring small pelagic fish in the Bay of Biscay ecosystem, using indicators from an integrated survey
Provedor de dados: 5
Autores: 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

Heterotrophic protists as a trophic link between picocyanobacteria and the pearl oyster Pinctada margaritifera in the Takapoto lagoon (Tuamotu Archipelago, French Polynesia)
Provedor de dados: 5
Autores: 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

Seasonal variations in planktonic community structure and production in an atlantic coastal pond: The importance of nanoflagellates
Provedor de dados: 5
Autores: Dupuy, Christine; Ryckaert, Mireille; Le Gall, Solange; Hartmann, Hans.
The structure and summertime production of planktonic communities and the role of nondiatom planktonic cells were studied in coastal ponds, which are areas traditionally used for fattening and greening table-sized oysters. The abundance and biomass of nano-microplanktonic protists were determined at weekly intervals between February 1998 and February 1999 in a coastal pond without oysters in the French Atlantic coast near La Rochelle. The production of these microbiotas was determined in the summer period. The structure of plankton communities revealed the following observations: (1) microphytoplanktonic cells were mostly diatoms and dinoflagellates, (2) microzooplanktonic cells were mainly ciliates, and (3) nanoplanktonic cells were represented by...
Tipo: Text
Palavras-chave: Food source microbial structure and production nanoflagellates; Coastal pond.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-2641.pdf

Mapping the Intertidal Microphytobenthos Gross Primary Production Part I: Coupling Multispectral Remote Sensing and Physical Modeling
Provedor de dados: 5
Autores: 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

Rapid responses of pristine marine planktonic communities in experimental approach to diuron and naphthalene (Juan de Nova Island, Western Indian Ocean)
Provedor de dados: 5
Autores: 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

Comparative analysis of the food webs of two intertidal mudflats during two seasons using inverse modelling: Aiguillon Cove and Brouage Mudflat, France
Provedor de dados: 5
Autores: 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

Rôle fonctionnel des protistes hétéro/mixotrophes dans le réseau trophique d'un écosystème conchylicole: le marais atlantique
Provedor de dados: 5
Autores: 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 &lt; 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

Influence of planktonic foodweb structure on a system's capacity to support pelagic production: an inverse analysis approach
Provedor de dados: 5
Autores: Marquis, Elise; Niquil, Nathalie; Vezina, Alain F.; Petitgas, Pierre; Dupuy, Christine.
Coupled plankton/small pelagic (SP) fish systems were analysed to assess how foodweb structure influences the export of carbon to pelagic fish during the spring bloom in the Bay of Biscay. The investigation of carbon export flows through inverse analysis was supplemented by estimating the carrying capacity for pelagic fish production by applying linear programming. A planktonic foodweb dominated by microbial pathways had the highest trophic efficiency owing to the tight coupling between planktonic trophic levels and predation pressure on mesozooplankton by fish. Moreover, the magnitude of the gap between carrying capacity and estimated carbon export was related to the size structure of primary producers, with the picophytoplankton-based foodweb having the...
Tipo: Text
Palavras-chave: Bay of Biscay; Carbon export; Carrying capacity; Inverse analysis; Planktonic foodweb; Small pelagic fish.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00035/14583/13375.pdf

Fifteen years of data from the PELGAS integrated survey (2000-2015): what have we learned on the Bay of Biscay pelagic ecosystem?
Provedor de dados: 5
Autores: 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
Ano: 2018
URL: http://archimer.ifremer.fr/doc/00445/55665/57331.pdf

Trophic ecology of European sardine Sardina pilchardus and European anchovy Engraulis encrasicolus in the Bay of Biscay (north-east Atlantic) inferred from delta C-13 and delta N-15 values of fish and identified mesozooplanktonic organisms
Provedor de dados: 5
Autores: 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

On biotic and abiotic drivers of the microphytobenthos seasonal cycle in a temperate intertidal mudflat: a modelling study
Provedor de dados: 5
Autores: 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
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00471/58226/60732.pdf

Impact of the oyster Crassostrea gigas on a microbial community in Atlantic coastal ponds near La Rochelle
Provedor de dados: 5
Autores: 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 &gt;5 pm protist abundance. On the contrary, planktonic organisms &lt;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

The spring mesozooplankton variability and its relationship with hydrobiological structure over year-to-year changes (2003–2013) in the southern Bay of Biscay (Northeast Atlantic)
Provedor de dados: 5
Autores: Dessier, Aurelie; Bustamante, Paco; Chouvelon, Tiphaine; Huret, Martin; Pagano, Marc; Marquis, Elise; Rousseaux, Frederic; Pignon-mussaud, Cecilia; Mornet, Francoise; Breret, Martine; Dupuy, Christine.
Mesozooplankton can be considered the most important secondary producers in marine food webs because they hold an intermediate position between the phytoplankton assemblage and the upper trophic levels. They also are a robust indicator of climatic and hydrological conditions. We conducted an analysis of the interannual variability of the spring mesozooplankton assemblage, as sampled by the PELGAS fisheries survey in the southern part of the Bay of Biscay (Northeast Atlantic Ocean) between 2003 and 2013. We examined hydrology and trophic drivers to explain the variability. Our results revealed that the subsurface temperature, the subsurface salinity, the biomasses of subsurface pico-, nano-, and microphytoplankton, and the copepod assemblage exhibited a...
Tipo: Text
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00439/55010/56428.pdf

Ecosystem spatial structure revealed by integrated survey data
Provedor de dados: 5
Autores: Petitgas, Pierre; Huret, Martin; Dupuy, Christine; Spitz, Jerome; Authier, Matthieu; Romagnan, Jean-baptiste; Doray, Mathieu.
Integrated marine survey series such as PELGAS provide comprehensive geo-referenced data over large sea areas in major ecosystem components with defined biological resolution and spatio-temporal sampling scale. These data enable to develop product at different levels of biological organization and spatial scale that are useful for ecosystem integrated assessments. Using the PELGAS integrated data series, we applied a generic procedure made of several steps to identify and map ecologically coherent ecosystem spatial units in the Bay of Biscay. First, the data were interpolated on a common spatial grid and organized as a time series of matrices containing at each time the variables as columns and the grid cell values as rows. The multi-table analysis method...
Tipo: Text
Palavras-chave: Integrated surveys; Ecosystems; Spatial structure; Multi-factor analysis; Bay of Biscay; Pelagic.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00403/51402/51977.pdf

Microbial community structure in the sea surface microlayer at two contrasting coastal sites in the northwestern Mediterranean Sea
Provedor de dados: 5
Autores: 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

Sequential resuspension of biofilm components (viruses, prokaryotes and protists) as measured by erodimetry experiments in the Brouage mudflat (French Atlantic coast)
Provedor de dados: 5
Autores: Dupuy, Christine; Mallet, Clarisse; Guizien, Katell; Montanie, Helene; Breret, Martine; Mornet, Francoise; Fontaine, Camille; Nerot, Caroline; Orvain, Francis.
Resuspension thresholds in terms of friction velocity were experimentally quantified for the prokaryotes, protists and for the first time, viruses of intertidal mudflat biofilms. Differences in resuspension thresholds could be related to the type, behaviour and size of microorganisms and their association with particles. Free microorganisms (viruses, bacteria and some nanoflagellates) were resuspended by weak flow at friction velocities lower than 2 cm s- 1. Chlorophyll a, some nanoflagellates and attached bacteria were resuspended together with the bed’s muddy sediment, which required friction velocities larger than 3 cm s- 1. Diatoms smaller than 60 μm were resuspended at velocities between 3 and 5 cm s- 1, while those larger than 60 μm were resuspended...
Tipo: Text
Palavras-chave: Viruses; Microorganisms; Resuspension; Benthic-pelagic coupling; Spatial distribution; Mudflat.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00168/27922/26196.pdf

The PELGAS survey: ship-based integrated monitoring of the Bay of Biscay pelagic ecosystem
Provedor de dados: 5
Autores: Doray, Mathieu; Petitgas, Pierre; Romagnan, Jean-baptiste; Huret, Martin; Duhamel, Erwan; Dupuy, Christine; Spitz, Jerome; Authier, Matthieu; Sanchez, Florence; Berger, Laurent; Doremus, Ghislain; Bourriau, Paul; Grellier, Patrick; Masse, Jacques.
The Pélagiques Gascogne (PELGAS) integrated survey has been developed by a multidisciplinary team of Ifremer and La Rochelle University scientists since 2000, joined by commercial fishermen in 2007. Its initial focus was to assess the biomass and predict the recruitment success of anchovy in the Bay of Biscay in spring. Taking advantage of the space and versatility of R/V Thalassa II, sampling has been progressively extended to other ecosystem components. PELGAS therefore further developed the second objective of monitoring and studying the dynamic and diverse Biscay pelagic ecosystem in springtime. The PELGAS survey model has allowed for the establishment of a long-term time-series of spatially-explicit data of the Bay of Biscay pelagic ecosystem since...
Tipo: Text
Palavras-chave: Pelagic ecosystem; Integrated ecosystem monitoring survey; Marine Strategy Framework Directive; Ecosystem variability; Bay of Biscay; Fishing vessels.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00407/51801/52401.pdf

Microbial interactions in marine water amended by eroded benthic biofilm: A case study from an intertidal mudflat
Provedor de dados: 5
Autores: 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 (&lt; 0.6 μ- and &lt; 10 μ filtrates) were diluted either with &lt; 30 kDa-ultrafiltered seawater or with this ultrafiltrate enriched with the respective size-fractionated benthic biofilm or with &lt; 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