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| Registros recuperados: 78 | |
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| Duperron, Sebastien; Gaudron, Sylvie M.; Lemaitre, Nolwenn; Bayon, Germain. |
| Tubeworms within the annelid family Siboglinidae rely on sulfur-oxidizing autotrophic bacterial symbionts for their nutrition, and are among the dominant metazoans occurring at deep-sea hydrocarbon seeps. Contrary to their relatives from hydrothermal vents, sulfide uptake for symbionts occurs within the anoxic subsurface sediment, in the posterior ‘root’ region of the animal. This study reports on an integrated microbiological and geochemical investigation of the cold seep tubeworm Escarpia southwardae collected at the Regab pockmark (Gulf of Guinea). Our aim was to further constrain the links between the animal and its symbiotic bacteria, and their environment. We show that E. southwardae harbors abundant sulfur-oxidizing bacterial symbionts in its... |
| Tipo: Text |
Palavras-chave: Sulfur-oxidizing bacteria; RTCA; Trace elements; RubisCO; Symbiosis. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00191/30251/28683.pdf |
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| Won, Eun-ji; Kim, Seung Hee; Go, Young-shin; Kumar, K. Suresh; Kim, Min-seob; Yoon, Suk-hee; Bayon, Germain; Kim, Jung-hyun; Shin, Kyung-hoon. |
| The increasing global consumption of seafood has led to increased trade among nations, accompanied by mislabeling and fraudulent practices that have rendered authentication crucial. The multi-isotope ratio analysis is considered as applicable tool for evaluating geographical authentications but requires information and experience to select target elements such as isotopes, through a distinction method based on differences in habitat and physiology due to origin. The present study examined recombination conditions of multi-elements that facilitated geographically distinct classifications of the clams to sort out appropriate elements. Briefly, linear discriminant analysis (LDA) analysis was performed according to several combinations of five stable isotopes... |
| Tipo: Text |
Palavras-chave: Authentication; Manila clam; Stable isotope; Traceability; Linear discriminant analysis. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00685/79701/82488.pdf |
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| Soulet, Guillaume; Menot, Guillemette; Bayon, Germain; Rostek, Frauke; Ponzevera, Emmanuel; Toucanne, Samuel; Lericolais, Gilles; Bard, Edouard. |
| Continental ice sheets are a key component of the Earth’s climate system, but their internal dynamics need to be further studied. Since the last deglaciation, the northern Eurasian Fennoscandian Ice Sheet (FIS) has been connected to the Black Sea (BS) watershed, making this basin a suitable location to investigate former ice-sheet dynamics. Here, from a core retrieved in the BS, we combine the use of neodymium isotopes, high-resolution elemental analysis, and biomarkers to trace changes in sediment provenance and river runoff. We reveal cyclic releases of meltwater originating from Lake Disna, a proglacial lake linked to the FIS during Heinrich Stadial 1. Regional interactions within the climate–lake–FIS system, linked to changes in the availability of... |
| Tipo: Text |
Palavras-chave: Ice dynamics; Meltwater routing; European hydrographic network. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00134/24489/22516.pdf |
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| Bastian, Luc; Revel, Marie; Bayon, Germain; Dufour, Aurelie; Vigier, Nathalie. |
| Chemical weathering of silicate rocks on continents acts as a major sink for atmospheric carbon dioxide and has played an important role in the evolution of the Earth’s climate. However, the magnitude and the nature of the links between weathering and climate are still under debate. In particular, the timescale over which chemical weathering may respond to climate change is yet to be constrained at the continental scale. Here we reconstruct the relationships between rainfall and chemical weathering in northeast Africa for the last 32,000 years. Using lithium isotopes and other geochemical proxies in the clay-size fraction of a marine sediment core from the Eastern Mediterranean Sea, we show that chemical weathering in the Nile Basin fluctuated in parallel... |
| Tipo: Text |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00376/48697/49030.pdf |
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| Skonieczny, Charlotte; Paillou, P.; Bory, A.; Bayon, Germain; Biscara, L.; Crosta, X.; Eynaud, F.; Malaize, B.; Revel, M.; Aleman, N.; Barusseau, J-p.; Vernet, R.; Lopez, S.; Grousset, F.. |
| The Sahara experienced several humid episodes during the late Quaternary, associated with the development of vast fluvial networks and enhanced freshwater delivery to the surrounding ocean margins. In particular, marine sediment records off Western Sahara indicate deposition of river-borne material at those times, implying sustained fluvial discharges along the West African margin. Today, however, no major river exists in this area; therefore, the origin of these sediments remains unclear. Here, using orbital radar satellite imagery, we present geomorphological data that reveal the existence of a large buried paleodrainage network on the Mauritanian coast. On the basis of evidence from the literature, we propose that reactivation of this major paleoriver... |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00303/41381/40559.pdf |
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| Fontanier, Christophe; Mamo, Briony; Toucanne, Samuel; Bayon, Germain; Schmidt, Sabine; Deflandre, Bruno; Dennielou, Bernard; Jouet, Gwenael; Garnier, Eline; Sakai, Saburo; Lamas, Ruth Martinez; Duros, Pauline; Toyofuku, Takashi; Sale, Aurelien; Belleney, Deborah; Bichon, Sabrina; Boissier, Audrey; Cheron, Sandrine; Pitel, Mathilde; Roubi, Angelique; Rovere, Mickael; Gremare, Antoine; Dupre, Stephanie; Jorry, Stephan. |
| In this short communication, we present a multidisciplinaty study of sedimentary records collected from a deep-sea interfluve proximal to the mouths of major northwestern Madagascan rivers. For the last 60 years, the seafloor has been repeatedly disturbed by the deposition of organic rich, tropical, terrestrial sediments causing marked reductions in benthic biodiversity. Increased soil erosion due to local land-use, deforestation and intensifying tropical cyclones are potential causes for this sedimentary budget and biodiversity shift. Our marine sedimentary records indicate that until now, these conditions have not occurred within the region for at least 20,000 years. |
| Tipo: Text |
Palavras-chave: Multidisciplinary study; Benthic foraminifera; Land-use; Tropical cyclones. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00413/52488/53276.pdf |
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| Pierre, Catherine; Bayon, Germain; Blanc-valleron, Marie-madeleine; Mascle, Jean; Dupre, Stephanie. |
| On the passive margin of the Nile deep-sea fan, the active Cheops mud volcano (MV; ca. 1,500 m diameter, ~20–30 m above seafloor, 3,010–3,020 m water depth) comprises a crater lake with hot (up to ca. 42 °C) methane-rich muddy brines in places overflowing down the MV flanks. During the Medeco2 cruise in fall 2007, ROV dives enabled detailed sampling of the brine fluid, bottom lake sediments at ca. 450 m lake depth, sub-surface sediments from the MV flanks, and carbonate crusts at the MV foot. Based on mineralogical, elemental and stable isotope analyses, this study aims at exploring the origin of the brine fluid and the key biogeochemical processes controlling the formation of these deep-sea authigenic carbonates. In addition to their patchy occurrence in... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00186/29735/28189.pdf |
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| Yu, Zhaojie; Colin, Christophe; Bassinot, Franck; Wan, Shiming; Bayon, Germain. |
| Chemical weathering of silicate rocks on continents is thought to have played an important role in the evolution of past atmospheric carbon dioxide over geologic timescales. However, the detailed links between continental weathering and climate change over shorter timescales, and their potential impact on sediment records deposited in the ocean, remain poorly understood. Here, we present clay mineralogy and strontium‐neodymium isotopic data for marine sediment records from the Northern Indian Ocean, with the aim of investigating the weathering response of large Himalayan river basins to orbital and millennial climate forcing. We show that past glaciated episodes of the late Quaternary corresponded to periods of increased physical erosion, associated with... |
| Tipo: Text |
Palavras-chave: Climate change<; /AUTHOR_KEYWORD>; Continental weathering<; /AUTHOR_KEYWORD>; Highlands and floodplains<; /AUTHOR_KEYWORD>; Carbon cycle<; /AUTHOR_KEYWORD>; Himalaya<; /AUTHOR_KEYWORD>. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00632/74434/74154.pdf |
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| Rousseau, Tristan C.c.; Roddaz, Martin; Moquet, Jean-sébastien; Delgado, Helga Handt; Calves, Gérôme; Bayon, Germain. |
| We report mineralogical, elemental (major and trace elements) and SrNd isotopic data for suspended particulate matter (SPM) samples from the Amazon, Orinoco and Maroni Rivers collected on a monthly basis over a one-year long hydrological cycle. The aim of this study was i) to characterize the mineralogical and geochemical composition of major South American tropical rivers and ii) to evaluate the effect of seasonal hydroclimate variations and changes in sediment discharge on the composition of these SPM. In addition to displaying particular mineralogical and geochemical signatures (e.g. Al/Si ratios, weathering indices), the Amazon, Orinoco and Maroni SPM are characterized by marked differences in 87Sr/86Sr (0.7213 ± 0.0030, 0.7288 ± 0.0018 and... |
| Tipo: Text |
Palavras-chave: Major and trace elements; Nd-Sr isotopes; Suspended sediments; Yearly hydrological cycle; Amazon River; Orinoco River; Maroni River. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00498/60962/64370.pdf |
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| Tallobre, Cedric; Loncke, Lies; Bassetti, Maria-angela; Giresse, Pierre; Bayon, Germain; Buscail, Roselyne; De Madron, Xavier Durrieu; Bourrin, Francois; Vanhaesebroucke, Marc; Sotin, Christine. |
| The Demerara Plateau, belonging to the passive transform margin of French Guiana, was investigated during the IGUANES cruise in 2013. The objectives of the cruise were to explore the poorly-known surficial sedimentary column overlying thick mass transport deposits as well as to understand the factors controlling recent sedimentation. The presence of numerous bedforms at the seafloor was observed thanks to newly acquired IGUANES bathymetric, high resolution seismic and chirp data, while sediment cores allowed the characterization of the deposits covering the mass transport deposits. Modern oceanographic conditions were determined in situ, using mooring monitoring over a 10-month period. Our data indicate the presence of a Contourite Depositional System... |
| Tipo: Text |
Palavras-chave: Marginal plateau; Contourite; Comet tail; Demerara Plateau. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00308/41957/41220.pdf |
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| Freslon, Nicolas; Bayon, Germain; Birot, Dominique; Bollinger, Claire; Barrat, Jean-alix. |
| This paper reports on a novel procedure for determining trace element abundances (REE and Y, Cr, Mn, Co) in seawater by inductively coupled plasma sector field mass spectrometry (ICP-SFMS). The procedure uses a combination of pre-concentration using co-precipitation onto magnesium hydroxides and addition of thulium spike. The validity of the method was assessed onto 25 ml volumes of certified reference materials (NASS- and CASS-4) and in house seawater standard. Procedural blanks were determined by applying the same procedure to aliquots of seawater previously depleted in trace elements by successive Mg(OH)(2) co-precipitations, yielding estimated contributions to the studied samples better than 1.1% for all elements, with the exception of Cr (<3.3%)... |
| Tipo: Text |
Palavras-chave: Trace elements; Rare earth elements (REE); Seawater; Mg(OH)(2) co-precipitation; ICP-MS; Thulium. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00041/15220/15855.pdf |
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| Bayon, Germain; Barrat, Jean Alix; Etoubleau, Joel; Benoit, Mathieu; Bollinger, Claire; Revillon, Sidonie. |
| We present a revised method for the determination of concentrations of rare earth (REE) and other trace elements (Y, Sc, Zr, Ba, Hf, Th) in geological samples. Our analytical procedure involves sample digestion using alkaline fusion (NaOH-Na2O2) after addition of a Tm spike, co-precipitation on iron hydroxides, and measurement by sector field-inductively coupled plasma-mass spectrometry (SF-ICP-MS). The procedure was tested successfully for various rock types (i.e., basalt, ultramafic rock, sediment, soil, granite), including rocks with low trace element abundances (sub ng g(-1)). Results obtained for a series of nine geological reference materials (BIR-1, BCR-2, UB-N, JP-1, AC-E, MA-N, MAG-1, GSMS-2, GSS-4) are in reasonable agreement with published... |
| Tipo: Text |
Palavras-chave: Digestion des Echantillons; Spike de Tm; ICP MS; MatEriaux de rEfErence; Echantillons gEologiques; ElEments du groupe des Terres Rares; Sample digestion; Tm spike; ICP MS; Reference materials; Geological samples; Rare earth elements. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6449.pdf |
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| Tanimizu, Masaharu; Sugiyama, Naoki; Ponzevera, Emmanuel; Bayon, Germain. |
| Isotope ratios of U-236/U-238 were measured at levels below 10(-7) by single collector ICPMS with a tandem quadrupole mass separation mechanism. Peak tailing of the prominent U-238(+) ion beam on the U-236(+) peak was reduced to the level of similar to 10(-10) by use of two quadrupole mass filters. The (UH+)-U-235 interference on U-236(+) was efficiently reduced to a UH+/U+ ratio of 1 x 10(-8) by an ion-molecule reaction between UH+ and O-2 in a collision/reaction cell placed between the two quadrupoles. The resultant detection limit for U-236/U-238 measurement was better than those reported by any other ICPMS study. The U-236/U-238 ratios, measured as (UO+)-U-236-O-16/(UO+)-U-238-O-16, were determined in the range 10(-9) to 10(-7) without correction for... |
| Tipo: Text |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00152/26358/24440.pdf |
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| Hardy, William; Penaud, Aurelie; Marret, Fabienne; Bayon, Germain; Marsset, Tania; Droz, Laurence. |
| A new 44 kyr long record of dinoflagellate (phytoplanktonic organisms) cysts (dinocysts) is presented from a marine sediment core collected on the Congolese margin with the aim of reconstructing past hydrological changes in the equatorial eastern Atlantic Ocean since Marine Isotopic Stage (MIS) 3. Our high-resolution dinocyst record indicates that significant temperature and moisture variations occurred across the glacial period, the last deglaciation and the Holocene. The use of specific dinocyst taxa, indicative of fluvial, upwelling and Benguela Current past environments for instance, provides insights into the main forcing mechanisms controlling palaeohydrological changes on orbital timescales. In particular, we are able, for the last 44 kyr, to... |
| Tipo: Text |
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| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00349/46006/45675.pdf |
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| Boswell, Steven M.; Toucanne, Samuel; Pitel-roudaut, Mathilde; Creyts, Timothy T.; Eynaud, Frédérique; Bayon, Germain. |
| Heinrich events (HEs) are dramatic episodes of marine-terminating ice discharge and sediment rafting during periods of cold North Atlantic climate. However, the causal chain of events leading to their occurrence is unresolved. Here, we demonstrate that enhanced surface melting of land-terminating margins of the southern Fennoscandian Ice Sheet (FIS) is a recurring feature of Heinrich stadials (HSs), the cold periods during which HEs occur. We use neodymium isotopes to show that the Channel River transported detrital sediments from the interior of eastern Europe to the Bay of Biscay in the northeast Atlantic Ocean at ca. 158–154 ka. Based on similar evidence from the last glacial period, we infer that this interval corresponds to the melting and retreat of... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00499/61065/64596.pdf |
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| Registros recuperados: 78 | |
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