Дополнительные функции родительного падежа в греческом языке

Целью данной работы является изучение возникновения дополнительных функций родительного падежа в греческом языке, как следствие взаимодействия кафаревусы и димотики

Sources of dissolved organic carbon in small volcanic mountainous tropical rivers, examples from Guadeloupe (French West Indies)

International audienceIn the tropical zone, small watersheds are affected by intense meteorological events. These events play an important role in the erosion of soils and therefore on the sources of organic carbon in small tropical rivers. We studied the geochemistry of two soils on Basse-Terre Island (French West Indies, FWI): ferralitic soil and Andosol. The two studied soils are very similar in terms of soil organic matter (SOM) and soil solution parameters. The total organic carbon (TOC) and total nitrogen (TN) contents vary between 1.7 and 92 g kg‐1 and between 0.1 and 5.5 g kg‐1, respectively, with the highest concentrations observed in the topsoil. The C/N ratios are relatively constant throughout the soil profiles (ca. 12). The carbon isotopic composition of SOM varies between ‐27.3‰ and ‐22.7‰ and presents an enrichment with increasing depth of soil profiles. Dissolved organic carbon (DOC) concentrations in soil solutions, varying from 3.2 to 91.3 mg L‐1, are similar for the both extraction used in lab (with milliQ water and Ca(NO3)2) but are higher than those measured in soil solutions sampled from lysimeters (0.65–1.46 mg L‐1). The isotopic compositions of DOC obtained by extractions and SOM are comparable, with δ13C values ranging from ‐28.6‰ to ‐25.8‰. The DOC sampled from lysimeters is systematically depleted in 13C compared to DOC obtained by extractions, with δ13C values of ‐33.8‰ to ‐30.6‰. The enrichment of δ13C of SOM through the soil profiles is either consistent with the carbon isotopic fractionation of SOM by decomposing organisms, or the differential mineralization of both labile and stable carbon stocks in soils. DOC concentrations in stream waters vary between 0.46 and 5.75 mg L‐1, and are generally lower during low water level than floods. The isotopic compositions of DOC in the rivers range from ‐38.9‰ to ‐27.2‰, with δ13C values, which are more depleted in 13C during low water level than flood events. The δ13CDOC of water river samples and soil solutions obtained by extraction and collected with lysimeters demonstrates that the DOC in rivers derives essentially from both the lixiviation of the soil surface layers during floods and groundwater flow during low water levels. Lixiviation of soil surface layers can be boosted by significant increases of intensity and duration of meteorological events and can strongly favor the release of surface soil organic matter in rivers and the impoverishment in nutrients of soil surface layers

Etude de l'orogenèse hercynienne au Maroc par la datation K-Ar de l'évolution métamorphique de schistes ardoisiers. Study of the Hercynian orogeny in Morocco by the K-Ar isotopic datation of metamorphic evolution in slates

K-Ar isotopic measurements on clay size fractions of slates allow the determination of their crystallization age, which is synchronous with cleavage development. In eastern Morocco, metamorphism and cleavage development occurred simultaneously around 370 Ma ago. In western and central Morocco, the ages range between 330-320 and 290 Ma, suggesting a progressive closure of the former Late Devonian -Dinantian sedimentary basin.L'analyse K-Ar de fractions granulométriques fines de schistes ardoisiers permet de déterminer l'époque de leur cristallisation synschisteuse. Dans le domaine oriental du Maroc, le métamorphisme syntectonique est ainsi daté de 370 Ma, tandis que dans le domaine occidental les âges s'échelonnent de 330-320 à 290 Ma, des bordures vers le centre de l'ancien bassin dévono-dinantien.Huon Sylvain, Piqué Alain, Clauer Norbert. Etude de l'orogenèse hercynienne au Maroc par la datation K-Ar de l'évolution métamorphique de schistes ardoisiers. Study of the Hercynian orogeny in Morocco by the K-Ar isotopic datation of metamorphic evolution in slates. In: Sciences Géologiques. Bulletin, tome 40, n°3, 1987. Métamorphisme anchizonal et développement de la schistosité. pp. 273-284

Suivi de l'érosion du carbone organique des sols à l'aide de traceurs isotopiques: deux études de cas pour des bassins versants cultivés sur fortes pentes (Laos, Venezuela)

Des méthodes de traçage isotopique basées sur l'utilisation de mesures d'activité de traceurs radioactifs ou de teneurs en isotopes stables peuvent nous aider à identifier et quantifier la contribution de sources différentes de carbone organique particulaire dans les écoulements générés par l'érosion hydrique sur les bassins versants ou améliorer les bilans d'érosion du carbone organique des sols. Ainsi, sur le bassin versant expérimental de Houay Pano (Laos), la redistribution le long des pentes du 137Cs provenant des retombées atmosphériques des essais atomiques des années 1960-1970, est corrélée avec la quantité de carbone organique contenue dans les premiers 30 cm des sols cultivés. Processus d'érosions, hydrique et aratoire, se combinent pour redistribuer le long des pentes simultanément matières organiques et particules argileuses des horizons superficiels des sols. Sur le bassin versant du Rio Boconó dans les Andes vénézuéliennes, les mesures de concentration en carbone organique particulaire, azote particulaire total, d13C et d15N effectuées sur les fractions fines (<50 µm) des matières en suspensions prélevées sur des parcelles expérimentales sont constantes au cours du ruissellement au-delà de « valeurs seuils » (30 ml.s-1 et 0.5 g.l-1 sur sol nu et sol sous culture de café). Les valeurs moyennes reflètent la composition moyenne des horizons de surface des sols (0-20 cm). Ces résultats indiquent qu'il est théoriquement possible (au-delà d'un seuil donné et pour une granulométrie de faible taille) d'estimer dans les écoulements la contribution respective en carbone organique particulaire de 2 sols de composition isotopique (d13C et d15N) suffisamment contrastée l'une par rapport à l'autre en utilisant des équations de mélange. La mesure de la teneur en 15N des matières organiques fines (<50 µm) en suspension, transportées par les cours d'eau pendant les épisodes de crues, peut nous permettre de mettre en évidence la contribution d'azote particulaire provenant de l'érosion incisive des roches du substratum géologique (shales, schistes et pélites). Sur le bassin versant du Rio Boconó où ce type de roches constitue une grande partie du sous-bassement géologique, l'ampleur de cette contribution dépend de l'intensité de l'épisode de crue. Ainsi, pendant un épisode de crue de forte intensité (période de retour : 10 ans) la contribution des matières organiques d'origine lithique (estimées à partir de l'azote particulaire) se trouve en proportion équivalente à celle fournie par l'érosion des sols s.s

Quantifying sediment source contributions in coastal catchments impacted by the Fukushima nuclear accident with carbon and nitrogen elemental concentrations and stable isotope ratios

International audienceThe Fukushima Dai-ichi Nuclear Power Plant accidental release of radioactive contaminants resulted in the significant fallout of radiocesium over several coastal catchments in the Fukushima Prefecture. Radiocesium, considered to be the greatest risk to the short and long term health of the local community, is rapidly bound to fine soil particles and thus is mobilized and transported during soil erosion and runoff processes. As there has been a broad-scale decontamination of rice paddy fields and rural residential areas in the contaminated region, one important long term question is whether there is, or may be, a downstream transfer of radiocesium from forests that covered over 65% of the most contaminated region. Accordingly, carbon and nitrogen elemental concentrations and stable isotope ratios are used to determine the relative contributions of forests and rice paddies to transported sediment in three contaminated coastal catchments. Samples were taken from the three main identified sources: cultivated soils (rice paddies and fields, n=30), forest soils (n=45), and subsoils (channel bank and decontaminated soils, n = 25). Lag deposit sediment samples were obtained from five sampling campaigns that targeted the main hydrological events from October 2011 to October 2014. In total, 86 samples of deposited sediment were analyzed for particulate organic matter elemental concentrations and isotope ratios, 24 from the Mano catchment, 44 from the Niida catchment, and 18 from the Ota catchment. Mann-Whitney U-tests were used to examine the source discrimination potential of this tracing suite and select the appropriate tracers for modelling. The discriminant tracers were modelled with a concentration-dependent distribution mixing model. Preliminary results indicate that cultivated sources (predominantly rice paddies) contribute disproportionately more sediment per unit area than forested regions in these contaminated catchments. Future research will examine if there are areas in particular where forest sources have elevated concentrations and may require some attention in the decontamination and monitoring of potential radiocesium downstream transfers

Zn isotopes in the suspended load of the Seine River, France: Isotopic variations and source determination

International audienceWe report Zn isotopic ratios (d66Zn) of river suspended particulate matter (SPM) and floodplain deposits (FD) from the Seine basin, France, with a precision < 0.05 per mil. A decrease in d66Zn from 0.30 per mil to 0.08 per mil is observed in SPM from the upstream to downstream parts of the fluvial system, associated with an increase in Zn concentration from 100 ppm to 400 ppm. The Zn/Al of SPM at the river mouth is up to five times greater than the Zn/Al of the natural background, and by normalizing to the later value we define a Zn enrichment factor. Suspended sediments from a temporal series of samples collected in Paris display a similar variation in d66Zn of between 0.08 per mil and 0.26 per mil, while showing an inverse relationship between the Zn enrichment factor and d66Zn. The amount of Zn transported as suspended load varies from 10% to 90%, as a function of increasing discharge. The d66Zn of SPM and the dissolved load are correlated, suggesting that adsorption processes are probably not the dominant process by which the Zn enrichment of SPM takes place. Instead, we interpret our data as reflecting the mixture of two main populations of suspended particles with distinct d66Zn. The first is characteristic of natural silicate particles transported by erosion processes to the river, while the second likely represents anthropogenic particles derived from wastewater treatment plants or combined sewer overflows. Based on isotopic ratios, we calculate that 70% of Zn in SPM of the Seine River in Paris is of anthropogenic origin

Quantifying sediment source contributions in coastal catchments impacted by the Fukushima nuclear accident with carbon and nitrogen elemental concentrations and stable isotope ratios

International audienceThe Fukushima Dai-ichi Nuclear Power Plant accidental release of radioactive contaminants resulted in the significant fallout of radiocesium over several coastal catchments in the Fukushima Prefecture. Radiocesium, considered to be the greatest risk to the short and long term health of the local community, is rapidly bound to fine soil particles and thus is mobilized and transported during soil erosion and runoff processes. As there has been a broad-scale decontamination of rice paddy fields and rural residential areas in the contaminated region, one important long term question is whether there is, or may be, a downstream transfer of radiocesium from forests that covered over 65% of the most contaminated region. Accordingly, carbon and nitrogen elemental concentrations and stable isotope ratios are used to determine the relative contributions of forests and rice paddies to transported sediment in three contaminated coastal catchments. Samples were taken from the three main identified sources: cultivated soils (rice paddies and fields, n=30), forest soils (n=45), and subsoils (channel bank and decontaminated soils, n = 25). Lag deposit sediment samples were obtained from five sampling campaigns that targeted the main hydrological events from October 2011 to October 2014. In total, 86 samples of deposited sediment were analyzed for particulate organic matter elemental concentrations and isotope ratios, 24 from the Mano catchment, 44 from the Niida catchment, and 18 from the Ota catchment. Mann-Whitney U-tests were used to examine the source discrimination potential of this tracing suite and select the appropriate tracers for modelling. The discriminant tracers were modelled with a concentration-dependent distribution mixing model. Preliminary results indicate that cultivated sources (predominantly rice paddies) contribute disproportionately more sediment per unit area than forested regions in these contaminated catchments. Future research will examine if there are areas in particular where forest sources have elevated concentrations and may require some attention in the decontamination and monitoring of potential radiocesium downstream transfers

Source contributions to radiocesium contaminated particulate matter deposited in a reservoir after the Fukushima accident

International audienceThe Fukushima nuclear accident resulted in the deposition of radiocesium over forested and rural landscapes northwest of the power plant. Although there have been several investigations into the dynamics of contaminated river sediment, less attention has been paid to the sources of deposited particulate matter in dams and reservoirs. In the Fukushima Prefecture, there are 10 significant dams and over a 1,000 reservoirs for both agricultural and surface water management. These reservoirs may have trapped a significant volume of radiocesium contaminated sediment, and understanding the sources of this material is important for the ongoing management of contamination in the region. Accordingly, the source of contaminated particulate matter (i.e. cultivated, forest and subsoils) deposited in the Mano Dam reservoir, Japan, was investigated with the analyses and modelling of carbon and nitrogen stable isotope ratios, total organic carbon and total nitrogen concentrations. Four sediment cores with lengths ranging from 29-41 cm were sampled in the Mano Dam, approximately 40 km northwest of the FDNPP. Source samples were taken from 46 forest soils, 28 cultivated soils and 25 subsoils in the region. Carbon-nitrogen parameters were analysed on all samples and a concentration-dependent distribution modelling approach was used to apportion source contributions. Three of the four cores sampled in the Mano Dam reservoir had distinct radiocesium peaks representative of the initial post-accident wash-off phase. Cultivated sources were responsible for 48% (SD 7%) of the deposited fine particulate matter in the three cores with the radiocesium peaks, whereas forests were modelled to contribute 27% (SD 6%) and subsoil sources 25% (SD 4%). Ongoing decontamination of cultivated sources in the Fukushima region should result in a decrease of contaminated matter deposited in reservoirs. More research is required to understand the potential ongoing source contributions from forested landscapes in this post-fallout environment