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Registros recuperados: 55
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A comparative Raman spectroscopic study of natural gas hydrates collected at different geological sites ArchiMer
Chazallon, B; Focsa, C; Charlou, Jean-luc; Bourry, Christophe; Donval, Jean-pierre.
Intact natural gas hydrates recovered on the West Aftican margin in the South Atlantic Ocean (ZaiAngo and Neris IIrojects) and from the Norwegian Sea (Hakon Mosby Mud Volcano) are investigated by micro-Raman spectroscopy at ambient pressure and low temperature. The gas hydrates collected at different geological sites contain a high methane concentration relative to other minor components that are slightly dispersed in the samples. They crystallize in a type I cubic lattice structure as also confirmed by our preliminary synchrotron diffraction results obtained on the ZaiAngo specimen. However, detailed analysis of selected microscopic areas reveals a variation in the gas distribution among the different specimens. Trace amounts of CO2 and H2S can be...
Tipo: Text Palavras-chave: Micro Raman spectroscopy; H2S hydrate; CH4 hydrate; Natural clathrate hydrates.
Ano: 2007 URL: http://archimer.ifremer.fr/doc/2007/publication-4303.pdf
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A detailed study of the Lucky-Strike hydrothermal site and discovery of a new hydrothermal site: « Menez-Gwen ». Preliminary results of DIVA 1 cruise (5-29 May, 1994) ArchiMer
Fouquet, Yves; Charlou, Jean-luc; Donval, Jean-pierre; Radford-knoery, Joel; Pelle, P; Ondreas, Helene; Lourenco, N; Segonzac, Michel; Tivey, Mk.
Tipo: Text
Ano: 1994 URL: http://archimer.ifremer.fr/doc/00070/18134/15682.pdf
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A Method for Detection of Trace Concentrations of Underivatized Amino Acid in Hydrothermal Fluids by Ion-Pairing Reversed-Phase UPLC-ESI-QTOF-MS ArchiMer
Konn, Cecile; Magner, Jörgen; Charlou, Jean-luc; Holm, Nils G; Alsberg, Tomas.
Investigation of amino acids in hydrothermal systems is of prime importance for the understanding of geochemistry and microbiology of hydrothermal vents and plumes, for carbon and metals global cycles, for metabolism of some hydrothermal microorganisms and for the origin of life issue. Extensive theoretical and experimental work on amino acids behaviour in hydrothermal fluids has been done, conversely only few data exist on natural samples. Because each hydrothermal vent is unique, the more data we collect the better we will be able to address each of these questions. Usually amino acids in hydrothermal fluids have been measured by HPLC-FLD. The chromatographic separation was at least 26 min and up to 135 min and the required derivatization step may be...
Tipo: Text Palavras-chave: Amino Acids; UPLC; Ion-Pairing; QTOF; Mass Spectrometry; Hydrothermal Fluids.
Ano: 2015 URL: http://archimer.ifremer.fr/doc/00271/38188/36339.pdf
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Activité hydrothermale et structure axiale des dorsales Est-Pacifique et médio-Atlantique ArchiMer
Bougault, Henri; Charlou, Jean-luc; Fouquet, Yves; Needham, David.
Tipo: Text
Ano: 1990 URL: http://archimer.ifremer.fr/doc/00070/18115/15663.pdf
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Analyse des Alkyls-Plomb en milieu marin - Formes 0rganiques alkyles stables et dégradées ArchiMer
Charlou, Jean-luc; Bisquay, Michèle.
Dans le cadre de l'étude du comportement géochimique de substances organo métalliques dans le milieu marin, ce rapport traite des techniques analytiques nécessaires pour identifier et quantifier ces composés sous leur forme alkyle organique stable ou sous leurs formes ionisées dégradées à l'état de trace (µg/1). Ces techniques sont appliquées à la famille et alkyls plomb. Les diverses formes alkyles stables sont identifiées et quantifiées par une technique de couplage chromatographie-absorption atomique sans flamme. Les formes ionisées dégradées sont dosables par spectrocolorimétrie. Ces techniques sont actuellement mises à profit pour suivre la dégradation des alkyls plomb dans le milieu marin. Les composés finaux de dégradation obtenus après un contact...
Tipo: Text
Ano: 1978 URL: http://archimer.ifremer.fr/doc/00132/24315/22313.pdf
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Analysis of light hydrocarbons in marine sediments by headspace technique: Optimization using design of experiments ArchiMer
Donval, Jean-pierre; Charlou, Jean-luc; Lucas, L..
Headspace technique is a common method to analyze light hydrocarbons in deep marine sediments. The use of an automatic headspace sampler instead of a manual injection is the guarantee for a better repeatability and furthermore it is less time consuming. But to increase the sensitivity and therefore, to achieve a better detection limit, it is necessary to optimize the automatic headspace sampler parameters. The theory of design of experiments was applied here by studying them. As a response, methane, which is an important gas in marine sediments, was chosen for its short analysis time. Regarding the parameters for automatic headspace sampler, eight variables were selected and then, a screening of them was carried out with a fractional factorial design to...
Tipo: Text Palavras-chave: Design of experiments; Headspace technique; Gas; Sediments.
Ano: 2008 URL: http://archimer.ifremer.fr/doc/2008/publication-6235.pdf
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Archaeal communities associated with shallow to deep subseafloor sediments of the New Caledonia Basin ArchiMer
Roussel, Erwan; Sauvadet, Anne-laure; Chaduteau, Carine; Fouquet, Yves; Charlou, Jean-luc; Prieur, Daniel; Cambon, Marie-anne.
P>The distribution of the archaeal communities in deep subseafloor sediments [0-36 m below the seafloor (mbsf)] from the New Caledonia and Fairway Basins was investigated using DNA- and RNA-derived 16S rRNA clone libraries, functional genes and denaturing gradient gel electrophoresis (DGGE). A new method, Co-Migration DGGE (CM-DGGE), was developed to access selectively the active archaeal diversity. Prokaryotic cell abundances at the open-ocean sites were on average similar to 3.5 times lower than at a site under terrestrial influence. The sediment surface archaeal community (0-1.5 mbsf) was characterized by active Marine Group 1 (MG-1) Archaea that co-occurred with ammonia monooxygenase gene (amoA) sequences affiliated to a group of uncultured...
Tipo: Text Palavras-chave: Marine subsurface sediments; Sea floor biosphere; Gradient gel electrophoresis; Microbial communities; Molecular diversity; Anaerobic oxidation; Sequence alignment; Phylogenetic trees; Extracellular DNA; Methane hydrate.
Ano: 2009 URL: http://archimer.ifremer.fr/doc/2009/publication-6801.pdf
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Axial accretion in the north Fiji basin (SW Pacific) between 16° and 22° S ArchiMer
Auzende, Jean-marie; Eissen, Jp; Lafoy, Y; Gente, P; Charlou, Jean-luc.
Tipo: Text
Ano: 1990 URL: http://archimer.ifremer.fr/doc/00070/18109/15657.pdf
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Campagne HYDROFAST: Etudes quantitatives de l'activité hydrothermale sur la Ride-Est Pacifique à 13°N ArchiMer
Bougault, Henri; Appriou, P; Birolleau, A; Charlou, Jean-luc; Crane, K; Etoubleau, Joel; Fouquet, Yves; Gente, P; Harmegnies, Francois; Landure, Jean-yves; Le Noac'H, A; Pelle, Henri; Sichler, Bertrand; Voisset, Michel; Watremez, Pierre; Vaslet, N; Jean Baptiste, P.
Tipo: Text
Ano: 1990 URL: http://archimer.ifremer.fr/doc/00070/18104/15652.pdf
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Campagne RIDELENTE: Structure de la dorsale Atlantique - Hétérogénéité du manteau et hydrothermalisme ArchiMer
Bougault, Henri; Appriou, P; Bienvenu, P; Cambon, Pierre; Charlou, Jean-luc; Collette, B; Donval, Jean-pierre; Dosso, Laure; Floch, G; Fouquet, Yves.
Tipo: Text
Ano: 1990 URL: http://archimer.ifremer.fr/doc/00070/18105/15653.pdf
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Characterisation of dissolved organic compounds in hydrothermal fluids by stir bar sorptive extraction - gas chomatography - mass spectrometry. Case study: the Rainbow field (36 degrees N, Mid-Atlantic Ridge) ArchiMer
Konn, Cecile; Charlou, Jean-luc; Donval, Jean-pierre; Holm, Nils G..
The analysis of the dissolved organic fraction of hydrothermal fluids has been considered a real challenge due to sampling difficulties, complexity of the matrix, numerous interferences and the assumed ppb concentration levels. The present study shows, in a qualitative approach, that Stir Bar Sorptive Extraction (SBSE) followed by Thermal Desorption - Gas Chromatography - Mass Spectrometry (TD-GC-MS) is suitable for extraction of small sample volumes and detection of a wide range of volatile and semivolatile organic compounds dissolved in hydrothermal fluids. In a case study, the technique was successfully applied to fluids from the Rainbow ultramafic-hosted hydrothermal field located at 36 degrees 14'N on the Mid-Atlantic Ridge (MAR). We show that...
Tipo: Text Palavras-chave: Sample preparation; Extraction; Organic compounds; Hydrothermal fluids; Ultramafic rocks.
Ano: 2012 URL: http://archimer.ifremer.fr/doc/00114/22514/20196.pdf
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Comparison of microbial communities associated with three Atlantic ultramafic hydrothermal systems ArchiMer
Roussel, Erwan; Konn, Cecile; Charlou, Jean-luc; Donval, Jean-pierre; Fouquet, Yves; Querellou, Joel; Prieur, Daniel; Cambon-bonavita, Marie-anne.
The distribution of Archaea and methanogenic, methanotrophic and sulfate-reducing communities in three Atlantic ultramafic-hosted hydrothermal systems (Rainbow, Ashadze, Lost City) was compared using 16S rRNA gene and functional gene (mcrA, pmoA and dsrA) clone libraries. The overall archaeal community was diverse and heterogeneously distributed between the hydrothermal sites and the types of samples analyzed (seawater, hydrothermal fluid, chimney and sediment). The Lost City hydrothermal field, characterized by high alkaline warm fluids (pH>11; T<95 °C), harbored a singular archaeal diversity mostly composed of unaffiliated Methanosarcinales. The archaeal communities associated with the recently discovered Ashadze 1 site, one of the deepest active...
Tipo: Text Palavras-chave: Archaea; Hydrothermal vent; Mid-Atlantic Ridge; 16S rRNA gene; Sediment; Ultramafic.
Ano: 2011 URL: http://archimer.ifremer.fr/doc/00067/17836/15573.pdf
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Coupled modeling of thermics and hydrogeology with the Cast3M code: application to the Rainbow hydrothermal field (Mid-Atlantic Ridge, 36A degrees 14'N) ArchiMer
Perez, Florian; Muegler, Claude; Jean-baptiste, Philippe; Charlou, Jean-luc.
We present a new numerical tool developed in the Cast3M software framework to model hydrothermal circulation. Thermodynamic properties of one-phase pure water are calculated from the International Association for the Properties of Water and Steam formulation. This new numerical tool is validated on several test cases of convection in closed-top and open-top boxes. Simulations of hydrothermal circulation in a homogeneous-permeability porous medium also give results in good agreement with already published simulations. This new numerical tool is used to construct a geometric and physical conceptual model of the Rainbow vent site at 36A degrees 14(')N on the Mid-Atlantic Ridge. Several configurations are discussed, showing that high temperatures and high mass...
Tipo: Text Palavras-chave: Hydrothermal system; Mid-ocean ridge; Numerical modeling; Rainbow vent site; Permeability.
Ano: 2013 URL: http://archimer.ifremer.fr/doc/00133/24463/23108.pdf
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Deepwater mantle He-3 plumes over the northern Mid-Atlantic Ridge (36 degrees N-40 degrees N) and the Azores Platform - art. no. Q03010 ArchiMer
Jean Baptiste, P; Fourre, E; Dapoigny, A; Charlou, Jean-luc; Donval, Jean-pierre.
As part of a multidisciplinary project aimed at studying mid-ocean ridge processes near the Azores, fifty water column profiles were analyzed for He-3/He-4 ratios in dissolved helium (a well-known hydrothermal tracer) from 36 degrees N to 40 degrees N along the Mid-Atlantic Ridge (MAR) and over the Azores Plateau. As expected, large delta(3) He anomalies could be observed over the Rainbow, Lucky Strike, and Menez Gwen hydrothermal sites. The main finding of the present study is the discovery of a large hydrothermal 3 He plume north of the Acor Fracture Zone (north AFZ site), with a CH4/He-3 ratio indicative of a basaltic-hosted hydrothermal system. Clear He-3 and CH4 anomalies, likely corresponding to unknown venting sites too, were also detected in the...
Tipo: Text Palavras-chave: Hydrothermal processes; Helium 3; Mid ocean ridges.
Ano: 2008 URL: http://archimer.ifremer.fr/doc/2008/publication-3876.pdf
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Distribution and behavior of dissolved hydrogen sulfide in hydrothermal plumes ArchiMer
Radford Knoery, Joel; German, C; Charlou, Jean-luc; Donval, Jean-pierre; Fouquet, Yves.
Through the deep ocean, hydrothermal plumes disperse high concentrations of key chemical tracers including He-3, CH4, Mn, Fe, H2S, etc. This paper focuses on the distribution and behavior of total dissolved sulfide (sulfide hereafter) in hydrothermal plumes to show that its plume concentration decreases to subnanomolar a few kilometers from the vents. We also report on sulfide removal rates determined at in situ conditions; we observe that they are two orders of magnitude greater than for open ocean seawater, consistent with sulfide being detected only in the vicinity of hydrothermal vents. From our observations, we infer that the sole presence of sulfide in hydrothermal plumes locates active venting at the kilometer scale.
Tipo: Text Palavras-chave: Chemical oceanography; Mid ocean ridges; Metals; Helium isotopes; Methane; Tracers; Hydrogen sulphide; Plumes; Hydrothermal activity.
Ano: 2001 URL: https://archimer.ifremer.fr/doc/2001/publication-688.pdf
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Etude du comportement géochimique des Alkyls Plomb dans le milieu marin. Essais préliminaires ArchiMer
Charlou, Jean-luc; Charlot, M.
Les premiers résultats concernant le comportement de composés organo-métalliques (alkyls plomb : plo:nb tétra-éthyl et méthyl) sont résumés dans ce rapport. La technique d'analyse du plomb organique dnns les sédiments (par minéralisation ou extraction au méthanol) a été mise au point. Les premières observations sont seulement basées sur les analyses de plomb minéral. La dégradation du PTE dans l'eau de mer et la phase sédimentaire est beaucoup plus rapide que celle du Ptm; lES RAYONS uv ONT UNE ACTION IMPORTANTE SUR CETTE D2GRADATION; Les PTE et PTM, de par leur densité élevée (+ de 1,5), leur insolubilité dans l'eau, diffusent très faiblement dans l'eau. Ils se dégradent sur le fond marin, où la densité du sédiment déposé jouera un rôle important dans la...
Tipo: Text
Ano: 1977 URL: http://archimer.ifremer.fr/doc/00132/24316/22314.pdf
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Etude géochimique du cuivre et des autres traces métalliques dans la partie Nord-Est de la Rade de Brest ArchiMer
Charlou, Jean-luc; Charlot, Michèle.
L'aspect géochimique des incidences de la réparation navale par les apports en traces métalliques (cuivre en particulier) contenus dans les peintures antifouling est étudié dans la zone N.E. de la rade de Brest. Les campagnes d'analyses d'eaux et les carottages sédimentaires ont permis de définir plusieurs zones touchées directement ou indirectement par ces rejets. L'étude chimique de la fraction fine inférieure à 63 microns des sédiments prélevés a mis en évidence une dissémination régulière en Cu - Pb - Zn en surface. Les évolutions des concentrations de ces métaux en fonction de la profondeur sont aussi tracées : les métaux semblent suivre la même loi d'accumulation. En laboratoire il a été possible d'étudier certains facteurs intervenant lors de la...
Tipo: Text
Ano: 1976 URL: http://archimer.ifremer.fr/doc/00132/24327/22326.pdf
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Evidence for intense REE scavenging at cold seeps from the Niger Delta margin ArchiMer
Bayon, Germain; Birot, Dominique; Ruffine, Livio; Caprais, Jean-claude; Ponzevera, Emmanuel; Bollinger, C.; Donval, Jean-pierre; Charlou, Jean-luc; Voisset, Michel; Grimaud, S..
For many trace elements, continental margins are the location of intense exchange processes between sediment and seawater, which control their distribution in the water column, but have yet to be fully understood. In this study, we have investigated the impact of fluid seepage at cold seeps on the marine cycle of neodymium. We determined dissolved and total dissolvable (TD) concentrations for REE and well-established tracers of fluid seepage (CH4, TDFe, TDMn), and Nd isotopic compositions in seawater samples collected above cold seeps and a reference site (i.e. away from any fluid venting area) from the Niger Delta margin. We also analyzed cold seep authigenic phases and various core-top sediment fractions (pore water, detrital component, easily leachable...
Tipo: Text Palavras-chave: Rare earth elements; Neodymium isotopes; Seawater; Cold seeps; Fe-Mn oxyhydroxides; Benthic fluxes.
Ano: 2011 URL: http://archimer.ifremer.fr/doc/00066/17754/15571.pdf
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Experimental study of gas hydrate formation and destabilisation using a novel high-pressure apparatus ArchiMer
Ruffine, Livio; Donval, Jean-pierre; Charlou, Jean-luc; Cremiere, Antoine; Zehnder, B. H..
A novel variable-volume type high-pressure apparatus has been designed, constructed and used for gas hydrate investigations. The apparatus has an operating temperature ranging from 253 K to 473 K and pressure ranging from 0.1 MPa to 60 MPa. Its central component consists of a viewing windows cell to which several sensors or analytical instruments can be connected. At its present configuration, a Raman spectrometer and a gas chromatograph are connected for the study of the liquid (or solid) and the gas phases respectively. The apparatus was used for the study of two different systems. The first system was composed of carbon dioxide (CO2) and water for which the hydrate formation and dissolution has been investigated by injecting water into liquid CO2. The...
Tipo: Text Palavras-chave: Gas hydrates; Thermogenic; Carbon dioxide; Formation; Destabilisation; Novel apparatus; Raman spectroscopy; Chromatography.
Ano: 2010 URL: http://archimer.ifremer.fr/doc/00006/11759/8472.pdf
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Extensive hydrothermal activity revealed by multi-tracer survey in the Wallis and Futuna region (SW Pacific) ArchiMer
Konn, Cecile; Fourre, E.; Jean-baptiste, P.; Donval, Jean-pierre; Guyader, Vivien; Birot, Dominique; Alix, Anne-sophie; Gaillot, Arnaud; Perez, Florian; Dapoigny, A.; Pelleter, Ewan; Resing, J. A.; Charlou, Jean-luc; Fouquet, Yves.
The study area is close to the Wallis and Futuna Islands in the French EEZ. It exists on the western boundary of the fastest tectonic area in the world at the junction of the Lau and North-Fiji basins. At this place, the unstable back-arc accommodates the plate motion in three ways: (i) the north Fiji transform fault, (ii) numerous unstable spreading ridges, and (iii) large areas of recent volcanic activity. This instability creates bountiful opportunity for hydrothermal discharge to occur. Based on geochemical (CH4, TDM, 3He) and geophysical (nephelometry) tracer surveys: (1) no hydrothermal activity could be found on the Futuna Spreading Center (FSC) which sets the western limit of hydrothermal activity; (2) four distinct hydrothermal active areas were...
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Ano: 2016 URL: http://archimer.ifremer.fr/doc/00347/45848/45505.pdf
Registros recuperados: 55
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