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| Registros recuperados: 99 | |
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| Allain, Gwenhael; Petitgas, Pierre; Lazure, Pascal. |
| A growth and survival model of the early life stages was run along virtual drift trajectories tracked in a hydrodynamic model to simulate the annual recruitment process of anchovy (Engraulis encrasicolus) in the Bay of Biscay (NE Atlantic). These biophysical simulations concerning three different years were analysed in order to investigate the influence of environment and spawning dynamics on the survival of larvae and juveniles. The location of space-time survival windows suggested major environmental mechanisms involved in simulated recruitment variability at the different scales - retention of larvae and juveniles in favourable habitats over the shelf margins and turbulence effects. These small-scale and meso-scale mechanisms were related to the... |
| Tipo: Text |
Palavras-chave: Turbulence; Retention; Recruitment; Physical biological interactions; Larval survival; IBM; Biscay; Anchovy. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3423.pdf |
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| Allain, Gwenhael; Petitgas, Pierre; Lazure, Pascal. |
| Variability in anchovy recruitment in Biscay is temptatively explained using variables from the stock and from the environment during the ichtyoplankton phase. Anchovy recruitment depends on many different processes : weight of adults and proportion of multiple spawners (age 2), river discharges, upwelling events at the coast and at the shelf break. Meteorological variables (wind, rain, tempe rature ) are forcing effects on the sea but they are not the effective processes that govern the production in the sea. So they do not relate directly to the survival of larvae and to recruitment. In Biscay, many different physical processes are active and used by anchovy which spawns in different physical systems (river plumes, open ocean enrichment systems).... |
| Tipo: Text |
Palavras-chave: Bio-physical coupling; Recruitment; Anchovy; Hdrodynamics; Step by step regression. |
| Ano: 1999 |
URL: http://archimer.ifremer.fr/doc/00391/50190/50814.pdf |
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| Ayata, Sakina-dorothee; Lazure, Pascal; Thiebaut, Eric. |
| For many marine species, larval dispersal plays a crucial role in population persistence, re-colonization of disturbed areas, and distribution of species range limits through the control of population connectivity. Along the French Atlantic coast (NE Atlantic), a biogeographical transition zone has been reported between temperate and cold-temperate marine faunal assemblages. Hydrodynamics in this area are highly complex and variable including numerous mesoscale features (e.g. river plumes, fronts, upwellings, low salinity lenses), which could constrain larval transport and connectivity. In this context, the aim of this study was to assess how hydrodynamic conditions and biological traits influence larval transport and contribute to population connectivity... |
| Tipo: Text |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00030/14174/11506.pdf |
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| Barnier, Bernard; Lazure, Pascal. |
| L'océanographie physique côtière a pour objet d'observer, de comprendre et de prévoir le fonctionnement hydrodynamique du milieu côtier, avec comme enjeux, dans le cadre d'applications pluridisciplinaires, la pollution côtière, la gestion et la préservation des écosystèmes et des ressources halieutiques, la contribution des zones côtières aux puits de carbone, l'hydrodynamique sédimentaire et les échanges eau - sédiments. Contrairement à l'océanographie du large, l'océanographie côtière n'a pas bénéficié de grands programmes internationaux (tel que le World Ocean Circulation Experiment -WOCE) pour structurer ses activités de recherche dans le domaine de l'observation et de la modélisation au niveau national ou international. De plus, les problèmes traités... |
| Tipo: Text |
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| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/00020/13162/10212.pdf |
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| Batifoulier, Francois; Kervella, Youen; Laborde, Renaud; Cuny, Jérôme; Caillaud, Matthieu; Lazure, Pascal; Cayocca, Florence. |
| Les fortes vitesses rencontrées à l’entrée de la Baie du Mont Saint-Michel font de cet environnement macro-tidal un endroit privilégié, en termes de ressources énergétiques, pour l’implantation d’une ferme d’hydroliennes. Afin d’établir plus précisément son potentiel énergétique et d’évaluer l’impact de l’implantation de telles machines sur son hydrodynamisme, une modélisation hydrodynamique de la Baie du Mont Saint-Michel est mise en oeuvre à l’aide du modèle de circulation régionale MARS3D (LAZURE & DUMAS, 2008) dans sa version tridimensionnelle. La validation hydrodynamique de cette configuration est réalisée à partir de comparaisons à des mesures courantologiques récentes (KERVELLA, 2010). A partir de cette modélisation, une cartographie du... |
| Tipo: Text |
Palavras-chave: Modélisation régionale; Hydroliennes; Baie du Mont Saint-Michel; Hydrodynamisme; Potentiel énergétique. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00195/30599/29055.pdf |
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| Batifoulier, Francois; Lazure, Pascal; Bonneton, Philippe. |
| Two hydrodynamic surveys based on acoustic Doppler current profiler (ADCP) and drift buoys measurements taken in summer 2008 and 2009 revealed poleward coastal jets of up to 32 cm s(-1) that lasted up to 22 d along the Aquitaine shelf in the southeastern area of the Bay of Biscay. A strong increase in bottom temperature was associated with these currents, up to 4 degrees C in 5 d at 54 m depth. These observations occurred after a few days of westerlies, cross-shore winds which were thought to have only a limited impact on longshore circulation. Here, the MARS3D hydrodynamic model was used with a schematic bathymetry of the southeastern area of the Bay of Biscay to reproduce and analyze these coastal jets. Simulations revealed that the triggering mechanism... |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00074/18569/16123.pdf |
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| Ben Ismail, Dhouha Kbaier; Lazure, Pascal; Puillat, Ingrid. |
| In marine sciences, many fields display high variability over a large range of spatial and temporal scales, from seconds to thus ousands of years. The longer and longer recorded time series, with an increasing sampling frequency, in this field are often nonlinear, nonstationary, multiscale and noisy. Their analysis faces new challenges and thus requires the implementation of adequate and specific methods. The objective of this paper is to highlight time series analysis methods already applied in econometrics, signal processing, health,etc. to the environmental marine domain, assess advantages and inconvenients and compare classical techniques with more recent ones. Temperature, turbidity and salinity are important quantities for ecosystem studies. The... |
| Tipo: Text |
Palavras-chave: Continuous wavelet transform; Cross-correlation; Empirical mode decomposition; Hilbert Huang Transform; Stationarity; Time dependent intrinsic correlation; Time series; Wavelets. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00324/43519/43050.pdf |
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| Bernard, Ismael; Duchene, Julie; Hily, Christian; Lazure, Pascal; Pouvreau, Stephane; Boudry, Pierre. |
| En complément du rapport final (Anonyme (2014). PERLE. Programme d'expérimentation et de recherche sur l'huître plate Ostrea edulis. Rapport final de l'ensemble du projet 2011-2014. http://archimer.ifremer.fr/doc/00248/35932/), ce rapport présente l'étude de la phase de dispersion des larves en rade de Brest et analyse le lien entre la quantité de larves émises et la quantité de larves captées. Ce lien, qui possède une forte composante spatiale, est appelé connectivité. Il est sous l’influence de la dispersion et de la survie des larves mais seule la dispersion larvaire, avec différents forçages biophysiques du milieu, a été considérée ici. Les effets de la localisation des zones d’émission et de captage, du comportement des larves, du vent ou de la durée... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00251/36233/34793.pdf |
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| Chapelle, Annie; Le Bec, Claude; Amzil, Zouher; Dreanno, Catherine; Guillou, Laure; Klouch, Khadidja; Labry, Claire; Le Gac, Mickael; Pineau-guillou, Lucia; Siano, Raffaele; Abernot, Chantal; Andrieux, Francoise; Caradec, Florian; Destombe, Christophe; Dia, A.; Doner, Anne; Duval, Julia; Gouriou, Jeremie; Lazure, Pascal; Le Brun, Luc; Le Gal, Dominique; Malestroit, Pascale; Petton, Sebastien; Plus, Martin; Quere, Julien; Savar, Veronique; Schmitt, Sophie; Terre, A.; Youenou, Agnes. |
| Suite à l’événement de grande ampleur d’efflorescence d’Alexandrium minutum et des toxicités associées en Rade de Brest en 2012, un projet a été élaboré avec la Région Bretagne dans le cadre du développement du port de Brest. L’Ifremer a organisé un échantillonnage dans l’estuaire de la rivière de Daoulas, zone la plus touchée en 2012, au cours des printemps-été 2013 et 2014. Un suivi de la présence d’A. minutum dans les sédiments a également été réalisé en hiver 2014. De ces suivis, des mesures réalisées au laboratoire à ce jour, des simulations du modèle Prévimer ainsi que des résultats du réseau Rephy et Velyger, il ressort que: * La rade de Brest peut aujourd’hui être considérée comme une zone à risque pour Alexandrium minutum. En effet, depuis 2012... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00254/36487/35029.pdf |
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| Charria, Guillaume; Repecaud, Michel; Quemener, Loic; Menesguen, Alain; Rimmelin-maury, Peggy; L'Helguen, Stephane; Beaumont, Laurence; Jolivet, Aurelie; Morin, Pascal; Mace, E; Lazure, Pascal; Le Gendre, Romain; Jacqueline, Franck; Verney, Romaric; Marie, Louis; Jegou, Paul; Le Reste, Serge; Andre, Xavier; Dutreuil, Vincent; Regnault, Jean-pierre; Jestin, Herve; Lintanf, Herve; Pichavant, Pascal; Retho, Michael; Allenou, Jean-pierre; Stanisiere, Jean-yves; Bonnat, Armel; Nonnotte, Lidwine; Duros, Wenceslas; Tarot, Stephane; Carval, Thierry; Le Hir, Pierre; Dumas, Franck; Vandermeirsch, Frederic; Lecornu, Fabrice. |
| To design a prototype for an Integrated Ocean Observing System (IOOS), at least three components are mandatory: a modeling platform, an in situ observing system and a structure to collect and to disseminate the information (e.g. database, website). The PREVIMER project followed this approach and in order to sustain model applications, PREVIMER has developed, funded and organized part of in situ observing networks in the Bay of Biscay and the Channel. For a comprehensive system, focus was addressed on fi xed platforms (MAREL MOLIT, MAREL Iroise, Island network and D4 for sediment dynamics), ships of opportunity (RECOPESCA program and FerryBoxes), and coastal profi lers (ARVOR-C/Cm). Each system is briefl y described and examples of scientifi c results... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00197/30785/29143.pdf |
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| Chauvaud, Laurent; Patry, Yann; Jolivet, Aurelie; Cam, Emmanuelle; Le Goff, Clement; Strand, Oivind; Charrier, Gregory; Thebault, Julien; Lazure, Pascal; Gotthard, Karl; Clavier, Jacques. |
| Understanding the relationship between growth and temperature will aid in the evaluation of thermal stress and threats to ectotherms in the context of anticipated climate changes. Most Pecten maximus scallops living at high latitudes in the northern hemisphere have a larger maximum body size than individuals further south, a common pattern among many ectotherms. We investigated differences in daily shell growth among scallop populations along the Northeast Atlantic coast from Spain to Norway. This study design allowed us to address precisely whether the asymptotic size observed along a latitudinal gradient, mainly defined by a temperature gradient, results from differences in annual or daily growth rates, or a difference in the length of the growing... |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00087/19861/17506.pdf |
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| Clavier, Jacques; Chauvaud, Laurent; Amice, Erwan; Lazure, Pascal; Van Der Geest, Matthijs; Labrosse, Pierre; Diagne, Ahmed; Carlier, Antoine; Chauvaud, Sylvain. |
| Benthic primary production and respiration were investigated at 4 sites representative of the major coastal communities bordering the Sahara Desert in the Banc d'Arguin, Mauritania, Western Africa. These sites correspond to intertidal Zostera noltii beds (270 km(2)), intertidal bare sediments (88 km(2)), subtidal Cymodocea nodosa beds (374 km(2)), and subtidal bare sediments (311 km(2)). At each site, production-irradiance relationships were established in situ in November 2008 and January 2010, and used to calculate daily carbon fluxes for these communities. In intertidal areas, compared to emersion, the gross maximal photosynthetic rates for Z. noltii bed and bare sediment communities were on average 8-and 7-fold higher during immersion, respectively;... |
| Tipo: Text |
Palavras-chave: Seagrass; Carbon metabolism; Intertidal; Subtidal; Respiration; Primary; Production; Western Africa. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00189/29987/28460.pdf |
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| Costoya, X.; Fernandez-novoa, D.; Decastro, M.; Santos, F.; Lazure, Pascal; Gomez-gesteira, M.. |
| The influence of Loire and Gironde River discharges over the sea surface temperature (SST) in the eastern Bay of Biscay (0.6º–36.6ºW, 44.2º–47.8ºW) was analyzed by means of two complementary databases (MODIS and OISST1/4). The area influenced by river plume showed a different SST when compared with the adjacent oceanic area for the months when the plume attains its highest extension (December, January, and February). Ocean was observed to warm at a rate of approximately 0.3ºC dec−1 while temperature at the area influenced by the rivers cooled at a rate of −0.15ºC dec−1 over the period 1982–2014. The mere presence of a freshwater layer is able to modulate the warming observed at adjacent ocean locations since the coastal area is isolated from the rest of... |
| Tipo: Text |
Palavras-chave: Loire; Gironde; SST; River plume; Warming modulation. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00311/42172/41472.pdf |
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| Davila, Xabier; Rubio, Anna; Artigas, Felipe; Puillat, Ingrid; Manso-narvarte, Ivan; Lazure, Pascal; Caballero, Ainhoa. |
| Mesoscale dynamics play a major role in several ocean processes, not only in the transport of momentum, heat, mass, particles and microorganisms but also in the provisioning of nutrients into the euphotic zone. Mesoscale processes can define niches where specific phytoplankton species flourish. However, this effect is not straightforward in coastal areas, which are submitted to a more complex interplay between different oceanic processes. In this context, the ETOILE campaign surveyed the CapBreton canyon area in the South-East of Bay of Biscay in early August 2017. The main objective of this study was to link the occurrence and distribution of phytoplankton with the mesoscale ocean processes. On top of the remote sensing data available for this area, such... |
| Tipo: Text |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00635/74733/74723.pdf |
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| Delord, Karine; Barbraud, Christophe; Pinaud, David; Letournel, Bruno; Jaugeon, Baptiste; Goraguer, Herle; Lazure, Pascal; Lormée, Hervé. |
| Among seabirds, alcids are particularly sensitive to bycatch in fisheries and oil pollution, yet their distribution at sea remains scarcely known in most of their breeding areas. GPS telemetry data of fifteen individuals of alcids (5 Razorbills 6 Common Murres and 4 Puffins) were analyzed to determine their distribution during the breeding period of 2016 at Saint Pierre and Miquelon Archipelago (SPM). Two analytical methods (threshold and a switching state-space model) were used to identify behavioral modes and foraging areas. We compared foraging movements and estimated the overlap between the species. Distribution and foraging covered an area located between SPM and Newfoundland. Our results revealed that the three species headed northward of their... |
| Tipo: Text |
Palavras-chave: Telemetry; Behavioral models; Animal movement; Distribution overlap; Fratercula arctica; Alca torda; Uria aalge. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00588/70038/68016.pdf |
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| Donnet, Sebastien; Lazure, Pascal; Ratsimandresy, Andry; Han, Guoqi. |
| While the dynamics of narrow fjords, i.e. narrow with respect to their internal Rossby radius, have been widely studied, it is only recently that interest sparked in studying the physics of broad fjords due to their importance in glacial ice melting (in Greenland, especially). Here, we present a comprehensive set of data collected in Fortune Bay, a broad, mid-latitude fjord located on the Northwest Atlantic shores. Aside from being wide (15–25 km width) and deep (600 m at its deepest), Fortune Bay also has the characteristics of having steep slopes, weak tides and of being strongly stratified from spring to fall. Thus, and since strong along-shore winds also characterise the region, this system is prone to interesting dynamics, generally taking the form of... |
| Tipo: Text |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00634/74635/74529.pdf |
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| Registros recuperados: 99 | |
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