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| Registros recuperados: 29 | |
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| Mougel, Berengere; Moreira, Manuel; Agranier, Arnaud. |
| We investigate in details helium isotope data reported in Mougel et al. (2014) for 14 basaltic samples collected on the East Pacific Rise by submersible (15 degrees 4N) where the ridge interacts with the Mathematician seamounts. Samples locations are separated by only few hundred meters across a 15km along-axis profile. The data reveal a strong geochemical variability that has never been observed at such high spatial resolution for helium isotope compositions. Moreover, they reveal an unusually high He-4/He-3 mantle component also characterized by unradiogenic lead, atypical in oceanic basalts. He-Pb systematics suggests a mixture between a nonradiogenic lead and radiogenic helium pyroxenitic component, recycled from the deep continental lithosphere and... |
| Tipo: Text |
Palavras-chave: Helium; Isotopes; Mantle geochemistry; MORB; Hot spot; EPR. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00639/75140/75500.pdf |
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| Decitre, S; Deloule, E; Reisberg, L; James, R; Agrinier, P; Mevel, C. |
| [1] Analyses of Li and Li isotopes in serpentinized peridotites have been performed using Thermo-Ionisation Mass Spectrometry (TIMS) and Secondary Ion Mass Spectrometry (SIMS) techniques on samples collected from the southwest Indian Ridge (SWIR). In the bulk samples, Li concentrations range from 0.6 to 8.2 ppm, while whole rock delta(6)Li values range from -2.9 to -14parts per thousand. In situ analyses display a greater range in both Li concentration (0.1-19.5 ppm) and Li isotopic composition ( -27 to +19parts per thousand), with the serpentinized portions having higher Li concentrations than the associated relict phases. These variations may reflect changes in Li partitioning and isotopic fractionation between serpentine and fluid with temperature and... |
| Tipo: Text |
Palavras-chave: Lithium; Isotopes; Geochemical cycle; Oceanic crust; Serpentinization. |
| Ano: 2002 |
URL: https://archimer.ifremer.fr/doc/00223/33403/31860.pdf |
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| Schmittner, Andreas; Bostock, Helen C.; Cartapanis, Olivier; Curry, William B.; Filipsson, Helena L.; Galbraith, Eric D.; Gottschalk, Julia; Carlos Herguera, Juan; Hoogakker, Babette; Jaccard, Samuel L.; Lisiecki, Lorraine E.; Lund, David C.; Martinez-mendez, Gema; Lynch-stieglitz, Jean; Mackensen, Andreas; Michel, Elisabeth; Mix, Alan C.; Oppo, Delia W.; Peterson, Carlye D.; Repschlaeger, Janne; Sikes, Elisabeth L.; Spero, Howard J.; Waelbroeck, Claire. |
| The carbon isotope composition (C-13) of seawater provides valuable insight on ocean circulation, air-sea exchange, the biological pump, and the global carbon cycle and is reflected by the C-13 of foraminifera tests. Here more than 1700 C-13 observations of the benthic foraminifera genus Cibicides from late Holocene sediments (C-13(Cibnat)) are compiled and compared with newly updated estimates of the natural (preindustrial) water column C-13 of dissolved inorganic carbon (C-13(DICnat)) as part of the international Ocean Circulation and Carbon Cycling (OC3) project. Using selection criteria based on the spatial distance between samples, we find high correlation between C-13(Cibnat) and C-13(DICnat), confirming earlier work. Regression analyses indicate... |
| Tipo: Text |
Palavras-chave: Carbon; Isotopes; Benthic; Foraminifera; Calibration. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00661/77326/78788.pdf |
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| VECCELLI,JULIANA CRISTINA; SIQUEIRA,DALMO LOPES DE. |
| ABSTRACT The aim of this study was to evaluate the response of mango plants ( L) ‘Mangifera indicaTommy Atkins’ cultivar to different NaCl concentrations. In this experiment, plants were grown in pots with washed sand and nutrient solution with 0, 10, 20 and 30 mM NaCl for 120 days. After this period, young leaves from the last growth spurt were harvested in a randomized block design, dried at 65 °C for 72 h and ground in a ball mill. Samples were dried again in an oven at 60 °C for 24 h and then the relative abundance of 13C and 12C isotopes was determined using mass spectrometer Sercon 20-20 isotope ratio model. Data were used to determine the carbon isotopic discrimination (?). It was concluded that ‘Tommy Atkins’ mango trees submitted to 30 mmol L-1... |
| Tipo: Info:eu-repo/semantics/other |
Palavras-chave: Mangifera indica; Salinity; Isotopes. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-29452017000703001 |
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| Thoby, Mary. |
| The redox conditions of the oceans evolved considerably during the Precambrian. This is mainly due to the arrival of the oxygen, at first generating oxygen oases, and then accumulating in the atmosphere during the Great Oxidation Event (GOE) ca. 2.45 Ga. However, the earliest traces of free oxygen during these periods, and the mechanisms of their sedimentary expression, remain poorly understood. For over a decade, the isotopic composition of molybdenum (δ98Mo) in sediments has been used as a global marine redox proxy.An elemental and isotopic study of the different phases constituting carbonate rocks was carried out using sequential digestions performed on carbonates of different ages and depositional environments. The results show that Mo is primarily... |
| Tipo: Text |
Palavras-chave: Redox; Précambrien; Carbonates; Molybdène; Isotopes; Attaque séquentielle; Sequential digestion; Precambrian; Molybdenum. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00663/77462/79129.pdf |
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| Schwartz, M.. |
| Zygochlamys patagonica (King and Broderip, 1832) is an ecosystem engineer mollusk which forms aggregations or banks, of different densities, in the main frontal systems of the SW Atlantic Ocean. The objectives of this work were to analyze the composition, biomass, diversity and species richness of the benthic invertebrate assemblages at different scallop densities as well as the variability of their trophic webs at high and low scallop densities. For this, samples of the benthic invertebrate assemblages were taken at the Shelf Break Front with a non-selective epibenthic dredge. It was evaluated if the abundance (ind/m2) or biomass (colonial species, gr/m2) of the different taxa varied with scallop densities. The results showed that from 14 analyzed, the... |
| Tipo: Theses and Dissertations |
Palavras-chave: Benthos; Ecological associations; Trophic relationships; Food webs; Biomass; Isotopes; Shelf fronts; Zygochlamys patagonica; Marine environment. |
| Ano: 2011 |
URL: http://hdl.handle.net/1834/4521 |
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| Oliveira,Ana Alix Mendes de Almeida; Vitti,Dorinha Miriam Silber Schmidt; Oliveira,Simone Raymundo de; Costa,Patrícia Barcellos; Neres,Marcela Abbado; Hermes,Paula Regina; Cavilhão,Cristiani; Konieczniak,Paula. |
| The objective of this study was to evaluate the use of the dietary cation-anion balance (DCAB) on the calcium metabolism in male Nellore steers with a mean age of 10 months. Three experimental diets were tested: a cationic diet, a diet consisting of Tifton hay only, and an anionic diet with +15.2, +23.9 and −10.0 mEq/100 g DM of DCAB values in the diet. The anionic diet was calculated as the addition of salts of ammonium chloride and magnesium sulfate. Based on the isotope dilution technique, the negative DCAB value used in this study (−10.0 mEq/100 g DM) does not affect calcium metabolism, especially endogenous losses and true absorption. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cattle; Feeds; Isotopes; Mineral metabolism. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982014001100601 |
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| Bourry, Christophe; Chazallon, Bertrand; Charlou, Jean-luc; Donval, Jean-pierre; Ruffine, Livio; Henry, Pierre; Geli, Louis; Cagatay, M. Namik; Inan, Sedat; Moreau, Myriam. |
| Gas hydrates and gas bubbles were collected during the MARNAUT cruise (May-June 2007) in the Sea of Marmara along the North Anatolian Fault system, Turkey. Gas hydrates were sampled in the western part of the Sea of Marmara (on the Western High), and three gas-bubble samples were recovered on the Western High, the Central High (center part of the Sea of Marmara) and in the Cinarcik Basin (eastern part of the Sea of Marmara). Methane is the major component of hydrates (66.1%), but heavier gases such as C-2, C-3, and i-C-4 are also present in relatively high concentration. The methane contained within gas hydrate is clearly thermogenic as evidenced by a low C-1/C-2 + C-3 ratio of 3.3, and carbon and hydrogen isotopic data (delta C-13(CH4) of -44.1 parts per... |
| Tipo: Text |
Palavras-chave: Isotopes; Thermogenic gas; Gas bubbles; Gas hydrate; Sea of Marmara. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6844.pdf |
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| Baronas, J. Jotautas; Torres, Mark A.; West, A. Joshua; Rouxel, Olivier; Georg, Bastian; Bouchez, Julien; Gaillardet, Jerome; Hammond, Douglas E.. |
| Solutes derived from the dissolution of silicate minerals play a key role in Earth’s climate via the carbon and other biogeochemical cycles. Silicon (Si) is a unique constituent of silicate minerals and a biologically important nutrient, so tracing its behavior in near-surface environments may provide important insights into weathering processes. However, Si released by weathering is variably incorporated into secondary mineral phases and biota, obscuring signals derived from primary weathering processes. Due to chemical similarities, Germanium (Ge) may help better understand the Si cycle and its relationship to chemical weathering. With this aim, we report new measurements of the concentration and isotopic composition of Ge for both the dissolved and... |
| Tipo: Text |
Palavras-chave: Germanium; Silicon; Isotopes; Rivers; Weathering; Fractionation. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00460/57196/59370.pdf |
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| Galbraith, Ed; Kienast, M; Pedersen, Tf; Calvert, Se. |
| An analysis of sedimentary nitrogen isotope records compiled from widely distributed marine environments emphasizes the global synchrony of denitrification changes and provides evidence for a strong temporal coupling of these variations to changes in nitrogen fixation as previously inferred. We explain the global coherence of these records by a simple physical control on the flux of dissolved oxygen to suboxic zones and the coupling to fixation via the supply of phosphorus to diazotrophs in suitable environments. According to our hypothesis, lower glacial-stage sea surface temperature increased oxygen solubility, while stronger winds in high-latitude regions enhanced the rate of thermocline ventilation. The resultant colder, rapidly flushed thermocline... |
| Tipo: Text |
Palavras-chave: Isotopes; Fixation; Denitrification. |
| Ano: 2004 |
URL: https://archimer.ifremer.fr/doc/00229/34026/32421.pdf |
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| Bastos,Murilo Q. R; Souza,Sheila M. F. Mendonça de; Santos,Roberto V; Lima,Bárbara A. F; Santos,Ricardo V; Rodrigues-Carvalho,Claudia. |
| This study investigated strontium isotopes in the dental enamel of 32 human skeletons from Forte Marechal Luz sambaqui (shellmound), Santa Catarina, Brazil, aiming at identifying local and non-local individuals. The archeological site presents pot sherds in the uppermost archeological layers. Dental enamel was also examined from specimens of terrestrial fauna (87Sr/86Sr = 0. 71046 to 0. 71273) and marine fauna (87Sr/86Sr = 0. 70917). The 87Sr/86Sr isotope ratio for individuals classified as locals ranged from 0. 70905 to 0. 71064 and was closer to the isotope ratio of the seawater than to the ratio of the terrestrial fauna, indicating a strong influence of marine strontium on the inhabitants of this sambaqui. The results indicate the existence of three... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Brazil; Human mobility; Isotopes; Prehistory; Shellmounds; Strontium. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652011000200030 |
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| Meyzen, Cm; Ludden, Jn; Humler, E; Luais, B; Toplis, Mj; Mevel, C; Storey, M. |
| We report new Sr, Nd, and Pb isotope data for Mid-Ocean Ridge Basalts (MORB) dredged between 35 and 69 degrees E along a similar to 4100 km section of the Southwest Indian Ridge (SWIR), which is one of the slowest spreading ridges of the global mid-ocean ridge system ( full rate of 16 mm yr(-1)). The SWIR appears isotopically more heterogeneous than other mid-ocean ridges over similar length scales and comparable sampling density. Isotopic variations are generally independent of ridge segmentation, and the degree of heterogeneity decreases from west to east. This decrease in heterogeneity correlates with the observed increase in axial depth and decrease in crustal thickness, commonly attributed to decreasing mantle potential temperature. Data for the... |
| Tipo: Text |
Palavras-chave: Southwest Indian Ridge; MORB; Isotopes; Indian Ocean; Lower crust; Mantle. |
| Ano: 2005 |
URL: https://archimer.ifremer.fr/doc/00232/34286/32655.pdf |
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| Malaize, B.; Joly, C.; Venec-peyre, M. -t.; Bassinot, F.; Caillon, N.; Charlier, K.. |
| High-resolution faunal and isotopic analyses of foraminifera were performed on core MD96-2073 (10 degrees 94'N, 52 degrees 62'E, 3142 m depth), located close to Socotra Island in the upwelling area of the Somali Basin ( NW Indian Ocean). This work focuses on Marine Isotopic Stage 6.5 in order to reconstruct paleo-upwelling changes and their links with the Arabian Sea summer monsoon and the migration of the Intertropical Convergence Zone (ITCZ). Correspondence and cluster analyses of planktonic foraminiferal abundances, partly controlled by temperature and water mass productivity, together with an upwelling intensification index, show the occurrence of a strong upwelling between 176 and 165 ka. This upwelling intensification responds to a northward... |
| Tipo: Text |
Palavras-chave: Paleoclimatology; Foraminifera; Isotopes; Indian monsoon; ITCZ; Sapropels; Upwelling. |
| Ano: 2006 |
URL: https://archimer.ifremer.fr/doc/00234/34487/33433.pdf |
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| Macia, A.. |
| A study to estimate the relative importance of mangrove primary carbon and nitrogen sources to five commercial penaeid shrimps species was done at Saco da Inhaca, a non-estuarine mangrove-fringed bay on Inhaca Island, southern Mozambique. Carbon and nitrogen stable isotope ratios were determined in a variety of primary producers (mangroves, epiphytes, phytoplankton and seagrasses), sediments and in five penaeid shrimp species (Penaeus (Fenneropenaeus) indicus, P. japonicus, P. semisulcatus, Metapenaeus monoceros and M. stebbingi), collected within the bay in different habitats and during two different periods. The penaeid shrimps showed 13C values ranging from â 13 to â 19 â °, (average of â 15.6 ± 0.4 â °, n=19) which is highly enriched compared to... |
| Tipo: Journal Contribution |
Palavras-chave: PENAEUS INDICUS; METAPENAEUS MONOCEROS; METAPENAEUS STEBBINGI; PENAEUS SEMISULCATUS; MARSUPENAEUS JAPONICUS; Shrimp culture; Nitrogen; Mangrove swamps; Carbon; Isotopes; Penaeid shrimp fisheries. |
| Ano: 2004 |
URL: http://hdl.handle.net/1834/1120 |
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| SABAT,PABLO; MARTÍNEZ DEL RÍO,CARLOS. |
| Passerines lack functional salt glands and to a large extent avoid feeding on marine invertebrates. An exception is Cinclodes nigrofumosus. Previous studies reported that the contents of its gastrointestinal tract had a lower osmolality than seawater suggesting that birds were supplementing their marine invertebrate diet with terrestrial invertebrates and fresh water at certain periods of the year. We report seasonal changes in the diet of C. nigrofumosus at two contrasting coastal localities in Central Chile and document the potential correlation between weather and feeding habits with osmoregulatory features in this species. We expected that C. nigrofumosus would increase its use of osmotically challenging marine dietary sources when fresh water is... |
| Tipo: Journal article |
Palavras-chave: Cinclodes; Isotopes; Renal function; Osmoregulation; Seasonal changes. |
| Ano: 2005 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2005000200009 |
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| Karr, Jd; Showers, Wj. |
| A detailed hydrographic survey of the water column of the Amazon shelf was performed using stable oxygen and hydrogen isotopes to determine the source and fate of waters on the shelf. delta(18)O-H2O and deltaD measurements were made on water column samples from approximately 60 stations (three depths per station) which were each collected during four Amasseds (A Multidisciplinary Amazon Shelf SEDiment Study) cruises: I8909-August 1989, falling river discharge; I9002-March 1990, rising river discharge; I9004-May 1990, peak discharge: I9113-November 1991, minimum discharge. Isotopes were compared with salinity and temperature measurements in order to identify water masses and mixing. The characteristics (salinity, temperature, delta(18)O, deltaD and d) are... |
| Tipo: Text |
Palavras-chave: Amazone; Isotopes; 18O; Deutérium; Hydrologie; Amazon; Isotope; O-18; Deuterium; Hydrography. |
| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/00322/43321/42933.pdf |
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| Beaumais, Aurelien; Bertrand, Herve; Chazot, Gilles; Dosso, Laure; Robin, Claude. |
| Gaua Island (also called Santa Maria), from the central part of the Vanuatu arc, consists of a large volcano marked by a caldera that hosts the active Mount Garet summit cone. In this paper, a geochemical study including Sr, Nd, Pb and Hf isotopic compositions of 25 lavas emitted since 1.8 Ma is presented, with a focus on the volcanic products that preceded (old volcanics, main cone and pyroclastic series) and followed (Mount Garet) the caldera forming event. All lavas show an island arc signature with enrichment in LILE and depletion in HFSE. Post-caldera lavas define a medium-K calc-alkaline trend, whereas lavas from the former main cone have high-K calc-alkaline compositions. Compared to the pre-caldera volcanic suite, the Mount Garet lavas have... |
| Tipo: Text |
Palavras-chave: Gaua; Vanuatu; Geochemistry; Isotopes; Subduction; Mantle source. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00319/43052/42557.pdf |
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| Registros recuperados: 29 | |
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