Consulta: creatorFacets:"Gentien, Patrick"
Registros recuperados: 21
Data/hora: 17/05/2024 05:57:44

A new device for in situ video and fluorescence analysis of marine particles. Applications to phytoplankton studies.
Provedor de dados: 5
Autores: Lunven, Michel; Lehaitre, Michel; Nascimben, Eric; Rouvillain, Julien; Berric, Roger; Le Gall, Erwan; Gentien, Patrick.
A new video-microscope has been developed for in situ investigation on marine particles. A field of view is produced by a laser beam at 473 nm. Individual cells or particles that entered this field of view appear as individual diffraction-limited spots of light, which are resolved from the dark background. A mobile high-pass optical filter (610 nm) can be controlled and displaced in front of the CCD camera, allowing simultaneously imaging and discrimination between fluorescing and non-fluorescing particles. We have the possibility to add a band pass filter for phycoerytrin detection. The system allows white light visualisation of particles ranging from 10 µm to several millimetres, depending on the zoom magnification. With the 610 nm high pass filter, the...
Tipo: Text
Palavras-chave: Surveillance; Phytoplancton; Phycotoxine.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/00144/25495/23649.pdf

Biorheological properties of intertidal organic fluff on mud flats and its modification of gill ventilation in buried sole Solea solea
Provedor de dados: 5
Autores: Jenkinson, Ian; Claireaux, Guy; Gentien, Patrick.
Intertidal mudflats are important nursery grounds for juveniles of many fish species. However, they are being used increasingly to farm bivalve molluscs, which produce large amounts of organic "fluff", overlying the mud. Fish such as sole, Solea solea, hide in this fluff from potential predators, but the energy consumed by respiring the fluff may be high due to its biorheological properties. We developed an ichthyoviscometer. It incorporates a freshly killed fish as a viscometer, and we developed it to measure the rheological properties of fluids and suspensions, including fluff, at scales encompassing those in gill ventilation. We have shown that the rheological behaviour of fluff is close to that of a gel with a yield stress strongly dependent on...
Tipo: Text
Palavras-chave: Fish; Organic matter; Gill ventilation; Biorheology; Organic fluff; Mud flats.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-2219.pdf

Contribution to toxicity assessment of Dinophysis acuminata (Dinophyceae)
Provedor de dados: 5
Autores: Marcaillou-le Baut, Claire; Mondeguer, Florence; Gentien, Patrick.
Blooms of Dinophysis in French coastal waters are implicated in most bans on marketing commercial bivalves. However, the relation between Dinophysis cell density and shellfish toxicity is not always consistent. Discrepancies may be due to the simple fact that it is nearly impossible to compare an integral over a few days (shellfish toxin content) and water samples. Furthermore, it seems that cells may have a variable specific toxicity. This work focuses on the variability in cell toxicity taking into account recent findings and using liquid chromatography coupled to mass spectrometry with an ion trap and electrospray interface. Esterified analogues of okadaic acid (DTX-4 and diol-esters) have been identified in cultures of Prorocentrum lima, another...
Tipo: Text
Palavras-chave: Liquid chromatography electrospray ionization mass spectrometry; Okadaic acid; Dinophysistoxins; Dinophysis acuminata.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/publication-605.pdf

Environmental status of the european seas
Provedor de dados: 5
Autores: Frid, Chris; Hammer, Cornelius; Law, Robin; Loeng, Harald; Pawlak, Janet F.; Reid, Philip C.; Tasker, Mark; Carlberg, Stig; Jakobsen, Tore Jakobsen; Rice, Jake Rice; Skjoldal, Hein Rune; Andrulewicz, Eugene; Bodoy, Alain; Calabrese, Anthony; Carlberg, Stig; Caspersen, Ove; Daan, Niels; Dahlin, Hans; Ehrich, Siegfried; Gentien, Patrick; Keizer, Paul; Leppänen, Juha-markku; Lima, Carmen; Margonski, Piotr; Noji, Tom; Nunes, Teresa; Rugg, Dornford; Sköld, Mattias.
Tipo: Text
Ano: 2003
URL: http://archimer.ifremer.fr/doc/00040/15135/12473.pdf

Essai de détermination d'une typologie des sédiments côtiers en fonction de l'apparition d'eaux colorées
Provedor de dados: 5
Autores: Arzul, Genevieve; Youenou, A.; Derrien, Annick; Gentien, Patrick; Crassous, M.p.; Lunven, M.
The study of different chemical parameters characterizing the coastal sediment, showed a possible relation between, respectively, high levels in organic matter and total copper, and the "red tide"  phenomenon.
Tipo: Text
Palavras-chave: Sédiment côtier; Eaux colorées; Matière organique; Cuivre; Coastal sediment; Red time; Organic matter; Copper.
Ano: 1988
URL: http://archimer.ifremer.fr/doc/00425/53708/54565.pdf

Etude de surveillance écologique sur le site de Flamanville année 1983
Provedor de dados: 5
Autores: Gentien, Patrick; Erard, Evelyne; Arnal, Olivier; Obaton, M; Quintin, Jean-yves; Belsher, Thomas; Chevalier, Claire; Dreves, Luc; Gresselin, Frederic; Guillaumont, Brigitte; Hamon, Dominique; Loarer, Ronan; Piriou, Jean-yves; Walker, Patrice.
In the framework of the building of a nuclear plant on the site of Flamanville, the C.N.E.X.O. was asked by Electricité de France, to take care of the ecological studies. These studies divide into three main phases: - Pilot studies, which are limited and aim to draw, initially, a portrait of the site. The Flamanville report was published in April 1976. - Project studies, which were spread over two years and resulted in the writing of a reference ecological assessment. These studies were carried out on the Flamanville site from July 1976 to July 1978 and the report was published in 1979. - Monitoring studies, which focus on the more significant or sensitive parameters of the site. This report presents the result of the first monitoring year (1983) and deals...
Tipo: Text
Ano: 1985
URL: http://archimer.ifremer.fr/doc/1985/rapport-6465.pdf

Etude des conséquences du fonctionnement de la centrale de Gravelines sur le milieu marin 1986
Provedor de dados: 5
Autores: Gentien, Patrick; Gros, Philippe; Le Fevre-lehoerff, Geneviève.
Une étude de rejet d'eau chaude (chlorée) du Centre de Production nucléaire a été effectuée selon deux méthodologies.
Tipo: Text
Palavras-chave: Centrale nucléaire; Gravelines; Impact; Dilution; Phytoplancton; Sonar; Nuclear power plant; Gravelines; Impact; Dilution; Phytoplankton; Sonar.
Ano: 1986
URL: http://archimer.ifremer.fr/doc/00006/11722/8391.pdf

EUPHORBE : EUtrophisation et PHénomènes d'ORigine BEnthique. Rapport d'activités 1987.
Provedor de dados: 5
Autores: Gros, Philippe; Blanchard, Michel; Chardy, Pierre; Gentien, Patrick; Hamon, Dominique; Monbet, Yves.
This report assesses the main actions of the first year of the EUPHORBE project, and consists of two parts : (i) the first one is the project proposal (objectives, scientific approach) ; in the second one, the 1987' field operations are related.
Tipo: Text
Ano: 1988
URL: http://archimer.ifremer.fr/doc/00107/21825/19413.pdf

Hydrodynamic conditions associated with the formation, maintenance and dissipation of a phytoplankton thin layer in a coastal upwelling system
Provedor de dados: 5
Autores: Velo-suarez, Lourdes; Fernand, Liam; Gentien, Patrick; Reguera, Beatriz.
During May-June 2005, a 17-d cruise was carried out in Ria de Pontevedra (Galician Rias Baixas) to study the physical-biological interactions that may lead to subsurface aggregations of phytoplankton organisms in thin layers (TLs). Physical processes governed the initiation and development, maintenance, and decline of a diatom (toxin producing Pseudo-nitzschia spp. and Chaetoceros socialis) TL during an upwelling relaxation-upwelling-downwelling sequence. Differences in shear profiles appeared to lead to the formation of a TL during upwelling events. These results reveal that the coupling between maximum values of shear and buoyancy frequency can shape a subsurface chlorophyll maximum (SCM) into a TL. The effect of shear upon phytoplankton patches, which...
Tipo: Text
Palavras-chave: Thin layer; Phytoplankton; Shear; Coastal upwelling system; Physical forcing; Coastal circulation.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00008/11905/9765.pdf

In situ video and diffraction analysis of marine particles
Provedor de dados: 5
Autores: Lunven, Michel; Gentien, Patrick; Kononen, K; Le Gall, Erwan; Danielou, Marie-madeleine.
A design for a new underwater video-system to detect and observe suspended particles is presented. Particles are collected and isolated in a rectangular box where they are highly illuminated by a white light plane. The total field of view is determined. The camera, equipped with a remote controlled zoom, can resolve particles sizes ranging from 25 mum to several millimetres. Real-time image analyses are therefore performed. Particle counts and size spectra are calculated and displayed. Total light intensity scattered by the illuminated particles is closely related to the back-scattering values determined by an optical back-scatter sensor. A particle size analyser using diffraction analysis is associated to this video-system on a custom profiler....
Tipo: Text
Palavras-chave: Image analysis; Fine scale distribution; Flocculation; Suspended matter; In situ measurement.
Ano: 2003
URL: https://archimer.ifremer.fr/doc/2003/publication-504.pdf

Le phytoplancton nuisible des côtes de France. De la biologie à la prévention
Provedor de dados: 5
Autores: Belin, Catherine; Berland, Brigitte; Erard-le Denn, Evelyne; Gentien, Patrick; Grzebyk, Daniel; Marcaillou Le Baut, Claire; Lassus, Patrick; Partensky, Frédéric.
Several phyloplankton species, whelher hloom-forming or not, have caused jish kilts or human intoxications or other nuisances on the coasts of France for the past ten years. The present review considers them under the foltowing aspects: morphology, cytology, physiology, hiochemislry, geographical distrihution, ecological requirements, toxicity and/or nuisances. These are principally the Dinoflagellates Dinophysis spp., Gymnodinium cf nagasakiense (= Gyrodinium cf aureolum) and Alexandrium minutum, and the Prymnesiophyte Phaeocystis spp. .. in addition, Ihree presumahly toxic species which were recently found on the French coasts are examined, namely : the Dinoflageltates Prorocentrum minimum and Gymnodinium spirale and the Silicoflageltate Dictyocha. Toxic...
Tipo: Text
Ano: 1991
URL: https://archimer.ifremer.fr/doc/1991/rapport-4210.pdf

Modélisation des blooms de Gymnodinium mikimotoï le long de la façade atlantique française : répartition spatiale
Provedor de dados: 5
Autores: Loyer, Sophie; Lazure, Pascal; Gentien, Patrick; Menesguen, Alain.
In order to study the occurrence of Gymnodinium mikimotoï bloom on the French Atlantic coast, a three-dimensional model of primary production was set up. The biological model was coupled to a hydrodynamic model previously developed at Ifremer, by the intermediary of transport, diffusion and heat fluxes. The cycles of three limiting elements for the phytoplankton growth were modelised: nitrogen, phosphorus and silicon. The second phase of the study aimed at reproducing the summer dinoflagellate blooms. In this new approach a model of the species Gymnodinium mikimotoï was coupled with the previous biomass model which provides the physical and chemical environments. The study focuses on the results obtained by this specific sub-model. The parametrisation was...
Tipo: Text
Palavras-chave: Turbulence; Dinoflagellés; Gymnodinium mikimotoï; Modèle; Nutriments; Turbulence; Dinoflagellate; Gymnodinium mikimotoï; Model; Nutrients.
Ano: 2001
URL: https://archimer.ifremer.fr/doc/00479/59100/61738.pdf

Motility and autotoxicity in Karenia mikimotoi (Dinophyceae)
Provedor de dados: 5
Autores: Gentien, Patrick; Lunven, Michel; Lazure, Pascal; Youenou, Agnes; Crassous, Marie-pierre.
Karenia mikimotoi is one of the most common red-tide dinoflagellates proliferating in the eastern North Atlantic and around Japan. Kills of marine fauna are associated with its blooms. In mixed water columns it migrates vertically, while in stratified water columns, the population remains confined within pycnocline layers. Wind events, increasing mixing and agitation initiate declines in its populations. This paper is focused on the formulation of mortality rate relative to shear rate. Autotoxicity is demonstrated by the use of a synthetic toxin. Bioconvection observed in cultures allows the establishment of a trade-off between phototropism, which leads to the local accumulation of cells, and their autotoxicity, which would prevent cell concentration. The...
Tipo: Text
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-2436.pdf

Phytoplankton assemblages and characterization of a Dinophysis acuminata population during an upwelling-downwelling cycle
Provedor de dados: 5
Autores: Gonzalez-gil, Sonsoles; Velo-suarez, Lourdes; Gentien, Patrick; Ramilo, Isabel; Reguera, Beatriz.
The distributions of Dinophysis acuminata, its potential prey Myrionecta rubra, and the microplankton populations associated with them, were studied in Ria de Pontevedra (NW Spain) during a 2 wk cruise that covered an upwelling-downwelling cycle, and during intensive sampling over 21 h at the end of the cruise. Special attention was focused on the characterization and physiological condition of D. acuminata. There was vertical segregation between a phytoplankton assemblage that was dominated by upwelling-promoted diatoms and another assemblage that was dominated by small dinoflagellates, located in the warmer surface layer (0 to 5 m) where D. acuminata was observed. High spatio-temporal variability was observed in the frequency of cells containing starch...
Tipo: Text
Palavras-chave: Harmful algal blooms; Plankton communities; Dinophysis acuminata; Myrionecta rubra; Predator-prey interactions.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00002/11296/7822.pdf

Rapid enzyme-linked immunosorbent assay for detection of the algal toxin domoic acid
Provedor de dados: 5
Autores: Litaker, R. Wayne; Stewart, Thomas N.; Eberhart, Bich-thuy L.; Wekell, John C.; Trainer, Vera L.; Kudela, Raphael M.; Miller, Peter E.; Roberts, Alice; Hertz, Cassandra; Johnson, Tyler A.; Frankfurter, Greg; Smith, G. Jason; Schnetzer, Astrid; Schumacker, Joe; Bastian, Jonnette L.; Odell, Anthony; Gentien, Patrick; Le Gal, Dominique; Hardison, I. Ransom; Tester, Patricia A.
Domoic acid (DA) is a potent toxin produced by bloom-forming phytoplankton in the genus which is responsible for causing amnesic shellfish poisoning (ASP) in humans. ASP symptoms include vomiting. diarrhea, and in more severe cases confusion. loss of memory. disorientation. and even coma or death. This paper describes the development and validation of a rapid. sensitive. enzyme linked immunosorbent assay test kit for detecting DA using a monoclonal antibody. The assay gives equivalent results to those obtained using standard high performance liquid chromatography. fluorenylmetbox-yearbonyl high performance liquid chromatography, or liquid chromatography-mass spectrometry methods. It has a linear range from 1.1-3 ppb and was used successfully to measure DA...
Tipo: Text
Palavras-chave: Test kit; Razor clams; Scallops; Mussels; ELISA; Domoic acid poisoning; ASP.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-6253.pdf

Scales characterising a high density thin layer of Dinophysis acuta Ehrenberg and its transport within a coastal jet
Provedor de dados: 5
Autores: Farrell, Hazel; Gentien, Patrick; Fernand, Liam; Lunven, Michel; Reguera, Beatriz; Gonzalez-gil, Sonsoles; Raine, Robin.
An investigation into the distribution of Dinophysis spp. in coastal waters off the south coast of Ireland was carried out in July 2007. Dinophysis acuta was present as a sub surface layer containing up to 55,000 cells L-1. The population had a high percentage of viable cells (mean: 89%; median: 94%; n = 24) with a high specific division rate (~0.55 d-1). The layer, of approximately 5 m thickness, did not coincide with the fluorescence maximum and was present as a patch of horizontal dimension less than 10 km x 7 km. Both conventional and towed undulating CTD used in conjunction with high vertical resolution sampling methods showed the patch of Dinophysis to move with a similar speed and direction as the coastal flow, which ran parallel to the coast in the...
Tipo: Text
Palavras-chave: Coastal jets; Dinophysis; Ireland; Transport.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00064/17538/17420.pdf

Surveillance Ecologique et Halieutique. Site de Flamanville. Année 1985
Provedor de dados: 5
Autores: Gentien, Patrick; Erard-le Denn, Evelyne; Quintin, Jean-yves; Dreves, Luc; Piriou, Jean-yves; Martin, Jocelyne; Veron, Gerard.
Surveillance n° 3 of Flamanville power-plant takes in account studies between february 1985 and march 1986. Hydrology , microbiology, phytoplancton, zooplancton, intertidal and sublittoral benthos, fishing are studied. The year 1985 is the last year before this power plant begins to work.
Tipo: Text
Palavras-chave: Surveillancce; Centrale nucléaire; Halieutique; Benthos; Pelagos; Surveillance; Power plant; Fishing; Benthos; Pelagos.
Ano: 1985
URL: http://archimer.ifremer.fr/doc/1985/rapport-6467.pdf

Surveillance Ecologique. Site de Flamanville Année 1984
Provedor de dados: 5
Autores: Gentien, Patrick; Erard-le Denn, Evelyne; Quintin, Jean-yves; Dreves, Luc; Guillaumont, Brigitte; Loarer, Ronan; Menesguen, Alain; Piriou, Jean-yves.
The Flamanville site has been the focus of a number of hydrobiological and biological measurement cycles in the years 1976-1978 and 1983-1984. The first project studies resulted in a reference ecological assessment based on 41 missions (229 stations). The monitoring studies conducted in 1983 and 1984 consisted of 16 campaigns (32 stations). The lowering of the number of samplings between both cycles is explained by the programs coherence; the monitoring indeed focuses on a number of parameters considered as the most significant or sensitive according to the most efficient strategy.
Tipo: Text
Ano: 1986
URL: http://archimer.ifremer.fr/doc/1986/rapport-6466.pdf

Suspended sediments in a macrotidal estuary: comparison and use of different sensors
Provedor de dados: 5
Autores: Lunven, Michel; Gentien, Patrick.
Measurements made using an in situ particle-sizer (PSA) were compared to those of an optical backscatter sensor (OBS) in a macrotidal estuary. Both estimate the total volume of particles. After comparison with dry weight of suspended matter sampled in the study area, the different measurements were converted into dry weight. In three different kinetic energy regimes, times series were coherent for most of the observations. Discrepancies of suspended sediment concentrations estimated by both sensors appeared under specific hydrodynamic conditions: they were related to occurrences of definite particle populations. Overestimations and underestimations of measurements by the instruments depend on the optical principles of the sensors (backscatter and...
Tipo: Text
Palavras-chave: Particle size; Suspended particulate matter; Aggregates; Taille de particule; Matières en suspension; Agrégats.
Ano: 2000
URL: http://archimer.ifremer.fr/doc/2000/publication-521.pdf

Tidal and wind-event variability and the distribution of two groups of Pseudo-nitzschia species in an upwelling-influenced ría
Provedor de dados: 5
Autores: Diaz, Patricio A.; Ruiz-villarreal, Manuel; Velo-suarez, Lourdes; Ramilo, Isabel; Gentien, Patrick; Lunven, Michel; Fernand, Liam; Raine, Robin; Reguera, Beatriz.
High-resolution physical and biological measurements were carried out in May-June 2007 during the ‘HABIT-Pontevedra 2007' survey in Ría de Pontevedra (Galician Rías Baixas, NW Spain) to study small-scale physical-biological interactions in the distribution of microphytoplankton, with special emphasis on harmful species. Longitudinal transects from the Ría to the adjacent shelf were sampled to describe the spring-neap tidal and circadian variability. An in situ particle profiler, a moored ADCP, and a towed undulating CTD (Scanfish) were used during the survey, which took place after an upwelling pulse at neap tides during a downwelling–upwelling cycle and coincided with the annual maximum of Pseudo-nitzschia spp. Cell maxima of P. seriata (2×106 cells L−1)...
Tipo: Text
Palavras-chave: Pseudo-nitzschia spp.; Upwelling-downwelling cycle; Spring-neap tidal variability; Thin layers; Circadian variability; Galician Rias.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00157/26794/24897.pdf

Vertical and horizontal controls of a haptophyte thin layer in the Bay of Biscay, France
Provedor de dados: 5
Autores: Farrell, Hazel; Gentien, Patrick; Fernand, Liam; Lazure, Pascal; Lunven, Michel; Youenou, Agnes; Reguera, Beatriz; Raine, Robin.
Investigations into the phytoplankton of the Bay of Biscay in July 2006 revealed an extensive bloom of an unidentified haptophyte species. High-resolution sampling techniques identified the region in the vicinity of the mouth of the Loire estuary as an area of high (106–107 cells l−1) cell densities of the haptophyte in a thin sub-surface layer. This organism dominated the phytoplankton population regionally. Measurements of the vertical distribution of horizontal shear showed that the population, located at ca. 20 m depth, was confined to a layer lying between two density discontinuities with high shear. Physical measurements indicated that the population was being advected southeastwards, along the coast. Seaward spreading of the population was also...
Tipo: Text
Palavras-chave: Haptophyte; Bay of Biscay; Horizontal dispersal; Thin layers.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00160/27129/25327.pdf