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Neodymium Isotopic Composition and Rare Earth Element Concentration Variations in the Coral and Solomon Seas
No full textInternational audienceSignificant progress has been made in the last decade on the understanding of the role of the Coral and Solomon Seas as major suppliers of waters and chemical elements to the equatorial Pacific. Yet, the location, depth, and processes of chemical enrichment of these waters remain poorly constrained. Neodymium (Nd) isotopic compositions (ε Nd) and rare earth element concentrations (REE) are powerful tracers of land-ocean chemical exchanges. Combined, they can greatly refine the characterization of these exchanges. Here we report profiles of ε Nd at 21 stations located in the Coral and Solomon Seas as part of the GEOTRACES GP-12 cruise that complement the rare earth element concentration (REE) profiles of Pham (Chemical Geology, 2019, 524 (May), 11-36). Waters exiting the Solomon Sea are generally slightly more radiogenic than the incoming ones, suggesting inputs of radiogenic material along their pathways across the Solomon Sea. This radiogenic material is brought to the surface waters via natural processes (rivers, volcanic dusts) and likely local mining activities. Noticeable ε Nd increases are also observed in subsurface and intermediate layers. All these processes indicate the occurrence of local Boundary Exchange (BE) processes, which are estimated to occur within a few days. Coupling hydrological and chemical tracers allows highlighting the landocean interactions affecting some water layers and quantifying the exchanged fluxes of Nd. Modifications of the Nd concentration and isotopic composition in the lower thermocline layer require an external flux of 7.9 ± 2.0 t(Nd)/yr only partly balanced by a scavenging flux of 1.8 ± 2.3 t(Nd)/yr, leading to a net influx of 6.1 ± 1.7 t(Nd)/yr. Regarding the Upper Circumpolar Deep Water, a total net flux of 105 ± 50 t(Nd)/yr is estimated, the external flux is relatively high (86 ± 31 t(Nd)/yr while the scavenging flux remains. These results refine the role of the Solomon Sea as a supplier of continental chemical elements to the Pacific equatorial waters
Spatially resolved observations of coronal type II radio bursts with multiple lanes
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The O2 night airglow in Venus atmosphere from VIRTIS VEX measurements: local time and temporal variation
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L'industriel mécène et l'artiste architecte : Eusebi Güell (1846-1918), Antonin Gaudi (1852-1926) : éducation, identité, expérience, lien social, savoirs
No full textEntre histoire de l'entreprise et architecture, dans une perspective comparative et interdisciplinaire, les multiples relations sont décrites et analysées dans des projets de connaissance particuliers.Les savoirs éducatifs sont le produit de savoir-faire où les gestes de l'artiste et de l'entrepreneur accompagnent les opérations de l'esprit, où les mouvements de la pensée grâce aux collaborations marquent aujourd'hui la ville de Barcelone
Principes et actions de formation en langues secondes en contextes migratoire et pandémique
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Analysis of Antioxidant Characteristics and Related Gene ExpressionProfiles of Rice Drought-Tolerance Lines Derived from Embryo-Soakingwith Alternanthera philoxeroides DNA Solution
No full textInternational audienceDrought is one of major abiotic stress limiting rice stable production. In thestudy, four rice cultivars, IAPAR9 (upland rice cultivar), H8 and H10 (drought-tolerance variant lines derived from 6527 embryo-soaked with Alternantheraphiloxeroides DNA solution) and 6527 (ordinary rice cultivar), were used tostudy the antioxidant characteristics of drought-resistant varieties by superoxidedismutase (SOD) activity, peroxidase (POD) activity, malondialdehyde (MDA)content and their related gene expression profiles. The results showed that theSOD activity, POD activity and MDA content were increased significantly underdrought stress, while decreased in the yield and its related traits such as seedsetting ratio, 1000-grain weight and grain number per panicle. The SOD andPOD activities in drought-tolerant rice (H8, H10 and IAPAR9) were significantlyhigher than those in drought-sensitive 6527. Less MDA content was producedin drought-tolerant rice (H8, H10 and IAPAR9) than sensitive 6527. The yieldof H8 was significantly higher than that of other cultivars, and the seed settingratio and 1000-grain weight from those with drought-tolerant were significantlyhigher than that of sensitive 6527. After drought stress, there were 11 genesrelated to antioxidant progress whose expression profiles changed significantlybetween H8 and 6527. These results suggested that drought tolerant cultivarsmaybe subdue harms from the peroxidation by inducing the express of relatedgenes of antioxidant process, further increasing the SOD activity and PODactivity. Thus, their enhancement of drought resistance could maintain thenormal growth and development under drought stress and achieve maximumphotosynthate storag
