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Sample records for deltasup 18o values

  1. Unexpected {delta}{sup 18}O and {delta}{sup 2}H Variability of Groundwater in the Eastern Paris Basin

    Energy Technology Data Exchange (ETDEWEB)

    Gourcy, L.; Petelet-Giraud, E. [BRGM Service EAU, Orleans (France)

    2013-07-15

    The Paris Basin covers about one-third of the total surface area of France. In 2009, two campaigns sampling 25 boreholes tapping Tertiary aquifers were carried out in the Basin. These aquifers are recharged at a similar altitude and the groundwater age is too young to have registered climate change. In the past, regional studies included the use of isotopes to understand groundwater origin and dynamics. Both {delta}{sup 18}O and {delta}{sup 2}H as well as ages (CFC/SF{sub 6)} and chemical components were determined in all collected samples. A noticeable stable isotope 'anomaly' appears in the south-western part of the Basin, where the average {delta}{sup 18}O and {delta}{sup 2}H values are more depleted and do not fit the pattern given by the continental effect in this area. A regional particularity of the spatial distribution of such isotopes in precipitation may be possible, but should be confirmed by additional work. (author)

  2. Isotopic variations ({delta}{sup 13} C and {delta}{sup 18} O) in Siderastrea stellata (Cnidaria-Anthozoa), Itamaraca island, State of Pernambuco, Northeastern Brazil

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    Ferreira, Valderez P.; Sial, Alcides N. [Pernambuco Univ., Recife, PE (Brazil). Dept. de Geologia. Lab. de Isotopos Estaveis; Mayeal, Elga M.; Exner, Marco Antonio [Pernambuco Univ., Recife, PE (Brazil). Dept. de Zoologia. Lab. de Macro e Megabentos

    1998-12-01

    Isotopic determinations for O and C were performed in coral skeletons collected in beach rocks from two localities (Orange and Catuama), Itamaraca Island, north littoral of the State of pernambuco, northeastern Brazil. Large variations of {delta}{sup 18} O and {delta}{sup 13} C in corals from both localities are found, the largest ones being observed at the Orange locality {delta}{sup 13} C in this locality varies from -0.8 to +1.8% PDB and {delta}{sup 1.8} O from -5.3 to -1.8% PDB, while at the Catuama locality, they vary from -1.8 to 0.1% PDB and -3.8 to -2.7% PDB, respectively. Large variations in {delta}{sup 18} O (up to 2.5%) coupled with weakly defined positive correlation between {delta}{sup 18} O and {delta}{sup 13} C, can be attributed to temperature variations as consequence of climatic perturbations. Temperature estimates, calculated from {delta}{sup 18} O values, assuming isotopic equilibrium with seawater, yield values between 24.9 deg C and 43.1 deg C at Orange, and from 28.4 deg C to 35 deg C at Catuama, all of them (expect one growth band from one sample) are high enough for the full development of the coral colony. Temperature average is 31.4 deg C at Orange, which is a little bit higher than that at Catuama, but both of them indicate thermal stress conditions. In all analyzed specimens, expect for one, at Orange, T increases was accompanied by decreasing in the organic activity, as suggested by corresponding negative {delta}{sup 13} C anomaly. Therefore, the observed bleaching is possibly related to thermal stress and the high T may be related to the El Nino-Southern Oscillation (ENSO) warning event. On the other hand, anthropogenic action at Orange, local of intense tourism throughout the year, coupled with high rate of sedimentation in the region, may contribute to the observed coral bleaching. (author)

  3. Controls of {delta}{sup 34}S and {delta}{sup 18}O in dissolved sulphate: Learning from a detailed survey in the Llobregat River (Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Otero, Neus [Departament Cristal . lografia, Mineralogia i Diposits Minerals, Facultat de Geologia, Universitat de Barcelona, Marti i Franques, s/n, 08028 Barcelona (Spain); Grup d' Hidrogeoquimica, Departament de Geologia Ambiental, Institut de Ciencies de la Terra ' Jaume Almera' , CSIC, Lluis Sole i Sabaris, s/n, 08028 Barcelona (Spain)], E-mail: notero@ub.edu; Soler, Albert; Canals, Angels [Departament Cristal . lografia, Mineralogia i Diposits Minerals, Facultat de Geologia, Universitat de Barcelona, Marti i Franques, s/n, 08028 Barcelona (Spain)

    2008-05-15

    The S and O isotopic composition of dissolved SO{sub 4}, used as a tracer for SO{sub 4} sources, was applied to the water of the Llobregat River system (NE Spain). The survey was carried out at 30 sites where surface water was sampled on a monthly basis over a period of 2a. The concentration of dissolved SO{sub 4} varied from 20 to 1575 mg L{sup -1}. Sulphur isotopic compositions clustered in two populations: one - 93% of the samples - had positive values with a mode of +9 per mille ; the other had negative values and a mode of -5 per mille . Data for {delta}{sup 18}O{sub SO{sub 4}} showed a mean value of +11 per mille , with no bi-modal distribution, though lower values of {delta}{sup 18}O corresponded to samples with negative {delta}{sup 34}S. These values can not be explained solely by the contribution of bedrock SO{sub 4} sources: that is, sulphide oxidation and the weathering of outcrops of sulphates, though numerous chemical sediments exist in the basin. Even in a river with a high concentration of natural sources of dissolved SO{sub 4}, such as the Llobregat River, the {delta}{sup 34}S values suggest that dissolved SO{sub 4} is controlled by a complex mix of both natural and anthropogenic sources. The main anthropogenic sources in this basin are fertilizers, sewage, potash mine effluent and power plant emissions. Detailed river water sampling, together with the chemical and isotopic characterisation of the main anthropogenic inputs, allowed determination of the influence of redox processes, as well as identification of the contribution of natural and anthropogenic SO{sub 4} sources and detection of spatial variations and seasonal changes among these sources. For instance, in the Llobregat River the input of fertilisers is well marked seasonally. Minimum values of {delta}{sup 34}S are reported during fertilization periods - from January to March - indicating a higher contribution of this source. The dual isotope approach, {delta}{sup 34}S and {delta}{sup 18}O

  4. The dynamics of central Main Ethiopian Rift waters: Evidence from {delta}D, {delta}{sup 18}O and {sup 87}Sr/{sup 86}Sr ratios

    Energy Technology Data Exchange (ETDEWEB)

    Rango, Tewodros, E-mail: tewodros.godebo@duke.edu [Division of Earth and Ocean Sciences, Nicholas School of the Environment, Duke University, Durham, NC 27708 (United States)] [Addis Ababa University, Department of Earth Sciences, P.O. Box 1176, Addis Ababa (Ethiopia); Petrini, Riccardo; Stenni, Barbara [University of Trieste, Department of Geosciences, Via Weiss 1, I-34100 Trieste (Italy); Bianchini, Gianluca [Istituto di Geoscienze e Georisorse-CNR, Pisa (Italy)] [Department of Earth Sciences, University of Ferrara, Via Saragat 1, 44100 Ferrara (Italy); Slejko, Francesca [University of Trieste, Department of Geosciences, Via Weiss 1, I-34100 Trieste (Italy); Beccaluva, Luigi [Department of Earth Sciences, University of Ferrara, Via Saragat 1, 44100 Ferrara (Italy); Ayenew, Tenalem [Addis Ababa University, Department of Earth Sciences, P.O. Box 1176, Addis Ababa (Ethiopia)

    2010-12-15

    Research highlights: {yields} Chemical and isotope ({delta}D, {delta}{sup 18}O and {sup 87}Sr/{sup 86}Sr) techniques are applied to understand various hydrological processes in the Main Ethiopian Rift. {yields} Some of the studied groundwaters display a depleted {delta}D-{delta}{sup 18}O composition when compared to the present-day average precipitation, thus suggesting that the rift floor aquifers also contains paleo-meteoric waters recharge associated with deep flow system. {yields} The pristine waters coming from the highlands display isotopic compositions characterized by less radiogenic {sup 87}Sr/{sup 86}Sr (and more depleted {delta}D, {delta}{sup 18}O). This isotopic signature subsequently evolves towards higher {sup 87}Sr/{sup 86}Sr by an interaction with the more radiogenic rhyolites of the rift and their weathered and redeposited products. - Abstract: Water samples from cold and geothermal boreholes, hot springs, lakes and rivers were analyzed for {delta}D, {delta}{sup 18}O and {sup 87}Sr/{sup 86}Sr compositions in order to investigate lake water-groundwater mixing processes, water-rock interactions, and to evaluate groundwater flow paths in the central Main Ethiopian Rift (MER) of the Ziway-Shala basin. Different ranges of isotopic values were recorded for different water types: hot springs show {delta}{sup 18}O -3.36 to +3.69 and {delta}D -15.85 to +24.23, deep Aluto-Langano geothermal wells show {delta}{sup 18}O -4.65 to -1.24 and {delta}D -12.39 to -9.31, groundwater wells show {delta}{sup 18}O -3.99 to +5.14 and {delta}D -19.69 to +32.27, whereas the lakes show {delta}{sup 18}O and {delta}D in the range +3.98 to +7.92 and +26.19 to +45.71, respectively. The intersection of the Local Meteoric Water Line (LMWL: {delta}D = 7 {delta}{sup 18}O + 11.2, R{sup 2} = 0.94, n = 42) and the Local Evaporation Line (LEL: {delta}D = 5.63{delta}{sup 18}O + 8, n = 14, R{sup 2} = 0.82) was used to estimate the average isotopic composition of recharge water into the

  5. Multivariate analysis of calcareous nanno fossils and stable isotopic ({delta}{sup 18}O and {delta}{sup 13}C) in the upper Campanian - lower Maastrichtian of the Campos Basin, Brazil; Analise multivariada em nanofosseis calcarios e isotopos estaveis ({delta}{sup 18}O e {delta}{sup 13}C) do Campaniano superior - Maastrichtiano inferior na Bacia de Campos

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    Oliveira, Luiz Carlos Veiga de [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas. Gerencia de Bioestratigrafia e Paleoecologia]. E-mail: lcveiga@petrobras.com.br; Rodrigues, Rene; Lemos, Valesca Brasil

    2005-05-01

    Qualitative analysis in calcareous nanno fossils is a powerful tool for bio stratigraphic uses, principally in identification of bio zones and determination of relative age. But quantitative studies must be applied for pale oceanographic applications and high resolution bio stratigraphy. In order to better understand the relationships between the different species of nanno fossils, new methodologies and non-traditional correlation tools were tested on a 18 m upper Campanian - lower Maastrichtian core from Campos Basin. Multiple regression helped to determine the best counting method. Watznaueria barnesae and Micula decussata dominate the fossil assemblage and have inverse abundances to each other. Both were opportunist species in competition for nutrients. Q mode factorial analysis (57 samples, 19 variables) was applied to the same core and shows that two factors explain 99.2% of the total variance of the micro fossil assemblage. The first factor represents 83.6% and the second factor only 15.6% of the total variance. The former is associated with Watznaueria barnesae, Cribrosphaerella ehrenbergii and Stradneria crenulata, which represent the original population of nano plankton. The latter factor is associated with Micula decussata, which is believed to represent the effect of solution at the sediment water interface. Both factors were used to develop a dissolution-sea level curve for nanno fossils. When combined with oxygen and carbon isotopes, this curve clearly shows that higher dissolution occurred during the late Campanian - early Maastrichtian time when {delta}{sup 18}O, {delta}{sup 13} C and TOC all had lower values. These correlations indicate a strong link between high sea levels, high temperatures and lower amount of continental organic debris. (author)

  6. Variability of {sup 10}Be and {delta}{sup 18}O in snow pits from Greenland and a surface traverse from Antarctica

    Energy Technology Data Exchange (ETDEWEB)

    Berggren, A.-M. [Dept. of Earth Sciences, Uppsala University, Villav. 16, 752 36 Uppsala (Sweden); Aldahan, A., E-mail: ala.aldahan@geo.uu.se [Dept. of Earth Sciences, Uppsala University, Villav. 16, 752 36 Uppsala (Sweden); Dept. of Geology, United Arab Emirates University, P.O. Box 17551 Al Ain (United Arab Emirates); Possnert, G. [Tandem Laboratory, Uppsala University, P.O. Box 529, 751 20 Uppsala (Sweden); Hansson, M. [Dept. of Physical Geography and Quaternary Geology, Stockholm University, 106 91 Stockholm (Sweden); Steen-Larsen, H.C. [Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej, 30,2100 Copenhagen (Denmark); Sturevik Storm, A. [Dept. of Earth Sciences, Uppsala University, Villav. 16, 752 36 Uppsala (Sweden); Moerth, C.-M. [Dept. of Geology and Geochemistry, Stockholm University, 106 91 Stockholm (Sweden); Murad, A. [Dept. of Geology, United Arab Emirates University, P.O. Box 17551 Al Ain (United Arab Emirates)

    2013-01-15

    To examine temporal variability of {sup 10}Be in glacial ice, we sampled snow to a depth of 160 cm at the NEEM (North Greenland Eemian Ice Drilling) drilling site in Greenland. The samples span three years between the summers of 2006 and 2009. At the same time, spatial variability of {sup 10}Be in glacial ice was explored through collection of the upper {approx}5 cm of surface snow in Antarctica during part of the Swedish-Japanese traverse from Svea to Syowa station during the austral summer in 2007-2008. The results of the Greenlandic {sup 10}Be snow suggested variable concentrations that apparently do not clearly reflect the seasonal change as indicated by the {delta}{sup 18}O data. The {sup 10}Be concentration variability most likely reflects also effects of aerosol loading and deposition pathways, possibly in combination with post-depositional processes. The Antarctic traverse data expose a negative correlation between {sup 10}Be and {delta}{sup 18}O, while there are weaker but still significant correlations to altitude and distance to the coast (approximated by the distance to the 70th latitude). These relationships indicate that geographical factors, mainly the proximity to the coast, may strongly affect {sup 10}Be concentrations in snow in Queen Maud Land, Antarctica.

  7. Variation in leaf water delta D and delta 18O values during the evapotranspiration process

    International Nuclear Information System (INIS)

    Leopoldo, P.R.; Foloni, L.L.

    1984-01-01

    A theoretical model was developed to evaluate leaf water delta D and delta 18 O variation in relation to: leaf temperature, relative humidity converted to leaf temperature and delta D and delta 18 O values of atmospheric water vapour and soil water. (M.A.C.) [pt

  8. Spatio-temporal distributions of delta>18O, delta D and salinity in the Arabian Sea: Identifying processes and controls

    Digital Repository Service at National Institute of Oceanography (India)

    Deshpande, R.D; Muraleedharan, P.M.; Singh, R.L.; Kumar, B.; Rao, M.S.; Dave, M.; Sivakumar, K.U.; Gupta, S.K.

    the geographic distributions of the delta>18O and S; (2) in spite of a large scatter, a statistically significant delta>18O–S relationship can be identified in much of the investigated part of the AS; (3) the delta>18O– delta...

  9. Seasonal mercury concentrations and {delta}{sup 15}N and {delta}{sup 13}C values of benthic macroinvertebrates and sediments from a historically polluted estuary in south central Chile

    Energy Technology Data Exchange (ETDEWEB)

    Diaz-Jaramillo, Mauricio, E-mail: mdiazjaramillo@conicet.gov.ar [Aquatic Systems Research Unit, EULA Chile Environmental Sciences Centre, Universidad de Concepcion (Chile); Munoz, Claudia; Rudolph, Ignacio [Aquatic Systems Research Unit, EULA Chile Environmental Sciences Centre, Universidad de Concepcion (Chile); Servos, Mark [Department of Biology, University of Waterloo, ON (Canada); Barra, Ricardo [Aquatic Systems Research Unit, EULA Chile Environmental Sciences Centre, Universidad de Concepcion (Chile)

    2013-01-01

    The Lenga Estuary is one of the most industrialized sites in south central Chile where the historic operation of chlor-alkali plants resulted in large quantities of mercury (Hg) being deposited into the estuary. This historical contamination may still represent a risk to the biota in the estuary. To investigate this four macroinvertebrates, Neotrypaea uncinata (ghostshrimp), Elminius kingii (barnacle), Hemigrapsus crenulatus (shore crab) and Perinereis gualpensis (ragworm) were collected seasonally from three different sites in the Lenga Estuary and one in a reference estuary (Tubul Estuary), and analyzed for Hg and stable isotopes ({delta}{sup 15}N and {delta}{sup 13}C). Mercury concentrations in Lenga sediments ranged from 0.4 {+-} 0.1 to 13 {+-} 3 mg/kg, while those in Tubul sediments ranged from 0.02 {+-} 0.01 to 0.07 {+-} 0.09 mg/kg. Total Hg concentrations of invertebrates were significantly different between estuaries (p < 0.05), but not by species or season for each estuary (p > 0.05). In contrast, organic Hg concentrations were different by species and season with shore crab muscle tissues exhibiting the greatest percent difference. Site-specific relationships demonstrated that total Hg concentrations in ragworm best reflected the total Hg sediment mercury concentrations. Signatures of {delta}{sup 13}C were correlated to the organic Hg % rather than total Hg. This suggests that organic Hg concentrations in these species were related to the carbon sources. -- Highlights: Black-Right-Pointing-Pointer Hg in sediments and biota from Lenga Estuary were elevated compared to nearby estuary. Black-Right-Pointing-Pointer Invertebrates showed interspecific and seasonal differences in terms of organic Hg %. Black-Right-Pointing-Pointer Total Hg levels in the ragworm best reflect Hg sediment gradient in Lenga Estuary. Black-Right-Pointing-Pointer Interspecific variation in {delta}{sup 13}C signatures indicated different feeding modes. Black

  10. Tests of size and growth effects on Arctic charr (Salvelinus alpinus) otolith δ18 O and δ13 C values.

    Science.gov (United States)

    Burbank, J; Kelly, B; Nilsson, J; Power, M

    2018-06-06

    Otolith δ 18 O and δ 13 C values have been used extensively to reconstruct thermal and diet histories. Researchers have suggested that individual growth rate and size may have an effect on otolith isotope ratios and subsequently confound otolith based thermal and diet reconstructions. As few explicit tests of the effect of fish in freshwater environments exist, here we determine experimentally the potential for related growth rate and size effects on otolith δ 18 O and δ 13 C values. Fifty Arctic charr were raised in identical conditions for two years after which their otoliths were removed and analyzed for their δ 18 O and δ 13 C values. The potential effects of final length and the Thermal Growth Coefficient (TGC) on otolith isotope ratios were tested using correlation and regression analysis to determine if significant effects were present and to quantify effects when present. The analyses indicated that TGC and size had significant and similar positive non-linear relationships with δ 13 C values and explained 35% and 42% of the variability, respectively. Conversely, both TGC and size were found to have no significant correlation with otolith δ 18 O values. There was no significant correlation between δ 18 O and δ 13 C values. The investigation indicated the presence of linked growth rate and size effects on otolith δ 13 C values, the nature of which requires further study. Otolith δ 18 O values were unaffected by individual growth rate and size, confirming the applicability of applying these values to thermal reconstructions of fish habitat. This article is protected by copyright. All rights reserved.

  11. Estimation of water transit time in soils under Amazon forest cover using variations in delta18O values

    International Nuclear Information System (INIS)

    Leopoldo, P.R.; Matsui, E.; Salati, E.

    1984-01-01

    The work was carried out at the forest reserve of the Instituto Nacional de Pesquisas da Amazonia, located at km 45 of Manaus, in an area characterized by Amazon vegetation of the 'terra-firme' type. To extract the soil water, four soil-water collecting stations were installed, and in each the porous cups were placed at 15, 25, 50, 80 and 120 cm depth from the soil surface. The rain-water and soil-water samples were collected only weekly for analysis of the 18 O content. In an attempt to estimate the soil-water transit time using the variation in 18 O values, a statistical model was used. This model is based on linear regression analysis applied to the values observed for soil water and rain water. From this analysis, regression coefficients are obtained which vary according to time. The values of the coefficients obtained can be adjusted generally, according to a quadratic regression, with the maximum value of the function representing the time in which the best statistical correlation between the observed delta 18 O values occurs. The time obtained from these correlations represents the mean time necessary for the water to run from one collecting point to the next. (author)

  12. Listening in on the past: what can otolith δ18O values really tell us about the environmental history of fishes?

    Science.gov (United States)

    Darnaude, Audrey M; Sturrock, Anna; Trueman, Clive N; Mouillot, David; Campana, Steven E; Hunter, Ewan

    2014-01-01

    Oxygen isotope ratios from fish otoliths are used to discriminate marine stocks and reconstruct past climate, assuming that variations in otolith δ18O values closely reflect differences in temperature history of fish when accounting for salinity induced variability in water δ18O. To investigate this, we exploited the environmental and migratory data gathered from a decade using archival tags to study the behaviour of adult plaice (Pleuronectes platessa L.) in the North Sea. Based on the tag-derived monthly distributions of the fish and corresponding temperature and salinity estimates modelled across three consecutive years, we first predicted annual otolith δ18O values for three geographically discrete offshore sub-stocks, using three alternative plausible scenarios for otolith growth. Comparison of predicted vs. measured annual δ18O values demonstrated >96% correct prediction of sub-stock membership, irrespective of the otolith growth scenario. Pronounced inter-stock differences in δ18O values, notably in summer, provide a robust marker for reconstructing broad-scale plaice distribution in the North Sea. However, although largely congruent, measured and predicted annual δ18O values did not fully match [ corrected]. Small, but consistent, offsets were also observed between individual high-resolution otolith δ18O values measured during tag recording time and corresponding δ18O predictions using concomitant tag-recorded temperatures and location-specific salinity estimates. The nature of the shifts differed among sub-stocks, suggesting specific vital effects linked to variation in physiological response to temperature. Therefore, although otolith δ18O in free-ranging fish largely reflects environmental temperature and salinity, we counsel prudence when interpreting otolith δ18O data for stock discrimination or temperature reconstruction until the mechanisms underpinning otolith δ18O signature acquisition, and associated variation, are clarified.

  13. Inter- and intra-specific variability in δ13C and δ18O values of freshwater gastropod shells from Lake Lednica, western Poland

    Science.gov (United States)

    Apolinarska, Karina; Pełechaty, Mariusz

    2017-09-01

    This study focuses on the inter- and intra-specific variability in δ13C and δ18O values of shells and opercula of gastropods sampled live from the littoral zone of Lake Lednica, western Poland. The δ13C and δ18O values were measured in individual opercula of Bithynia tentaculata and in shells of Bithynia tentaculata, Gyraulus albus, Gyraulus crista, Lymnaea sp., Physa fontinalis, Radix auricularia, Theodoxus fluviatilis and Valvata cristata. The gastropods selected for the study are among the species most commonly found in European Quaternary lacustrine sediments. The carbon isotope composition of the gastropod shells was species-specific and the same order of species from the most to the least 13C-depleted was observed at all sites sampled. Differences in shell δ13C values between species were similar at all sampling sites, thus the factors influencing shell isotopic composition were interpreted as species-specific. The δ18O values of shells were similar in all the species investigated. Significant intra-specific variability in shell δ13C and δ18O values was observed not only within the populations of Lake Lednica, which can be explained by heterogeneity of δ13C DIC, δ18O water and water temperature between the sites where macrophytes with snails attached were sampled, but also between individuals sampled from restricted areas of the lake's bottom. The latter points to the importance of factors related to the ontogeny of individual gastropods.

  14. First field-based observations of δ2H and δ18O values of precipitation and other water bodies in the Mongolian Gobi desert

    Science.gov (United States)

    Burnik Šturm, Martina; Ganbaatar, Oyunsaikhan; Voigt, Christian C.; Kaczensky, Petra

    2017-04-01

    Hydrogen (δ2H) and oxygen (δ18O) isotope values of water are widely used to track the global hydrological cycle and the global δ2H and δ18O patterns of precipitation are increasingly used in studies on animal migration, forensics, food authentication and traceability studies. However, δ2H and δ18O values of precipitation spanning one or more years are available for only a few 100 locations worldwide and for many remote areas such as Mongolia data are still scarce. We obtained the first field-based δ2H and δ18O isotope data of event-based precipitation, rivers and other water bodies in the extreme environment of the Dzungarian Gobi desert in SW Mongolia, covering a period of 16 months (1). Our study area is located over 450 km north-east from the nearest IAEA GNIP station (Fukang station, China) from which it is separated by a mountain range at the international border between China and Mongolia. Isotope values of the collected event-based precipitation showed and extreme range and a high seasonal variability with higher and more variable values in summer and lower in winter. The high variability could not be explained by different origin of air masses alone (i.e. NW polar winds over Russia or westerlies over Central Asia; analyzed using back-trajectory HYSPLIT model), but is likely a result of a combination of different processes affecting the isotope values of precipitation in this area. The calculated field-based local meteoric water line (LMWL, δ2H=(7.42±0.16)δ18O-(23.87±3.27)) showed isotopic characteristics of precipitation in an arid region. We observed a slight discrepancy between the filed based and modelled (Online Isotope in Precipitation Calculator, OIPC) LMWL which highlighted the difficulty of modelling the δ2H and δ18O values for areas with extreme climatic conditions and thus emphasized the importance of collecting long-term field-based data. The collected isotopic data of precipitation and other water bodies provide a basis for future

  15. Assessing Covariation of Holocene Monsoon Intensity and Local Moisture Conditions in Eastern and Southwestern Amazon Basin Using Speleothem δ18O and 87Sr/86Sr Values

    Science.gov (United States)

    Ward, B. M.; Wong, C. I.; Novello, V. F.; Silva, L.; McGee, D.; Cheng, H.; Wang, X.; Edwards, R. L.; Cruz, F. W., Sr.; Santos, R. V.

    2017-12-01

    δ18O records from South America offer insight into past variability of the South American Monsoon System (SAMS). Potential, however, for understanding local moisture conditions is limited as precipitation δ18O is strongly influenced by regional climate dynamics. Here we create Holocene speleothem 87Sr/86Sr records at 200-yr resolution using TIMS methods in the Center for Isotope Geochemistry at Boston College to complement existing Holocene δ18O speleothem records and investigate local moisture conditions above caves located in the eastern Amazon Basin (PAR - 4°S, 55°W) and southwestern Brazil (JAR - 21°S, 56°W). Speleothem 87Sr/86Sr variability is interpreted to reflect differences in the extent of water-rock interaction due to differences in infiltration rates under wet and dry conditions. Drier conditions promote longer residence time, enhanced water-rock interaction, and greater evolution of dripwater 87Sr/86Sr values from an initial isotopic signature acquired from the soil to the signature of the cave host rock. PAR speleothem 87Sr/86Sr values range from 0.71024 to 0.71067 and are bracketed by soil (0.71710 to 0.70956) and bedrock (0.70852 to 0.70899) values. JAR speleothem 87Sr/86Sr values range from 0.71216 to 0.71539 and are greater than bedrock values (0.70825 to 0.71219), although some speleothem values exceed the single analysis conducted of the soil isotopic composition (0.71473). JAR speleothem 87Sr/86Sr values increase from the early to mid Holocene, consistent with increase in local moisture availability associated with intensification of the SAMS suggested by decreasing δ18O values in many records from the region. Speleothem 87Sr/86Sr values at JAR decrease from the mid to late Holocene, consistent with an increase in δ18O values at PAR that suggest a decline in monsoon intensity. 87Sr/86Sr variability at JAR, however, is positively correlated with the δ18O record. Preliminary 87Sr/86Sr results from PAR are only broadly consistent with

  16. Determination Of Oxygen Isotope Ratio (18O-/16O) and Sulfur (34S-/32S) Value Of BaSO4 Din 5033 For Internal Standard

    International Nuclear Information System (INIS)

    Evarista Ristin, P.I.; Sidauruk, Paston; Wibagoyo; Djiono; Satrio

    2000-01-01

    It has been done an experiment to determine of oxygen( 18 O-/ 16 O) and Sulfur ( 34 S-/ 32 S) ) isotop value of BaSO 4 DIN 5033 (merck) for internal standard. The used technique for preparation of CO 2 gas to measure oxygen isotop ratio ratio (stated as deltaδ 18 O) is based on Rafter on Rafte method using graphite for reduction of BaSO 4 . Where the used technique for preparation of SO 2 gas to measure isotope sulphur ratio (started as δ 34 S) is based on Robinson - Kasakabe method using Cupro oxide to oxidize Ag 2 S. The result of this experiment is 11,48±0,41 0/00 and 5,00 plus minus ±0,33 o/oo for deltaδ 18 O and δ 34 S value respectively. Based on this experiment. BaSO 4 DIN 5033 can be used as internal standard because is values both oxygen and sulphur lie in the middle of range of its variation in nature. The result of interlab comparison shows that the value of this experiment is nearly similar to the value obtained from laboratorium of Pinstech-Pakistan. To acquire the result, it is necessary to carry out more interlab comparison

  17. Estimated values of the environmental tritium concentration and the altitude isotope effects of δD and δ18O in Hokkaido

    International Nuclear Information System (INIS)

    Ikeda, Mitsuyoshi; Takata, Sigeru; Matsueda, Hiroharu

    1998-01-01

    Tritium ( 3 H) concentration and stable isotopic ratios δD and δ 18 O are important environmental tracer data. In Hokkaido, however, hydrological studies using these data were difficult due to a lack of environmental tritium and the altitude isotope effect values. In this study, 3 H concentrations of Hokkaido wine were measured to estimate the past rain 3 H concentrations. In addition, environmental δD and δ 18 O samples taken on Mt. Daisetsuzan, the highest peak in Hokkaido, and in the Tokachi Plain were measured. The results obtained are as follows: Estimated concentrations of 3 H in Hokkaido were higher than those in Tokyo and Tsukuba, and were consistent with geographical 3 H levels in rain around Hokkaido. Some model calculations suggested that the 3 H concentrations in the 1950's and 1960's were at least 30% higher than those in Tokyo. The altitude isotope effects obtained were -1.75±0.30 per mille/100 m and -0.24±0.01 per mille/100 m for δD and δ 18 O, respectively. These values are almost the same as, or slightly lower than those in the Chubu and Tohoku districts. Using these data, the approximate age of groundwater and the altitude of original precipitation could be estimated. (author)

  18. An automated technique for measuring deltaD and delta18O values of porewater by direct CO2 and H2 equilibration.

    Science.gov (United States)

    Koehler, G; Wassenaar, L I; Hendry, M J

    2000-11-15

    The stable-oxygen and -hydrogen isotopic values (deltaD, delta18O) of porewater in geologic media are commonly determined on water obtained by extraction techniques such as centrifugation, mechanical squeezing, vacuum heating and cryogenic microdistillation, and azeotropic distillation. Each of these techniques may cause isotopic fractionation as part the extraction process and each is laborious. Here we demonstrate a new approach to obtain automated, high-precision deltaD and delta18O measurements of porewater in geologic sediments by direct H2- and CO2-porewater equilibration using a modified commercial CO2-water equilibrator. This technique provides an important and cost-effective improvement over current extraction methods, because many samples can be rapidly analyzed with minimal handling, thereby reducing errors and potential for isotopic fractionation. The precision and accuracy of direct H2- and CO2-porewater equilibration is comparable to or better than current porewater extraction methods. Finally, the direct equilibration technique allows investigators to obtain high-resolution (cm scale) porewater deltaD and delta18O profiles using cores from individual boreholes, eliminating the need for costly piezometers or conventional porewater extractions.

  19. Water circulation control on carbonate-{delta}{sup 18}O records in a low permeability clay formation and surrounding limestones: The Upper Dogger-Oxfordian sequence from the eastern Paris basin, France

    Energy Technology Data Exchange (ETDEWEB)

    Lavastre, Veronique, E-mail: veronique.lavastre@univ-st-etienne.fr [Universite de Lyon, Universite Jean Monnet, F-42023 Saint Etienne (France)] [CNRS, UMR 6524, LMV, F-42023 Saint Etienne (France)] [Laboratoire de Geochimie des Isotopes Stables, Institut de Physique du Globe de Paris and Universite Paris 7 - UMR CNRS 7154, 4, place Jussieu, 75252 Paris cedex 05 (France); Ader, Magali [Laboratoire de Geochimie des Isotopes Stables, Institut de Physique du Globe de Paris and Universite Paris 7 - UMR CNRS 7154, 4, place Jussieu, 75252 Paris cedex 05 (France); Buschaert, Stephane [Andra, Parc de la Croix Blanche, 7-8 rue Jean Monnet, 92 298 Chatenay-Malabry Cedex (France); Petit, Eddy; Javoy, Marc [Laboratoire de Geochimie des Isotopes Stables, Institut de Physique du Globe de Paris and Universite Paris 7 - UMR CNRS 7154, 4, place Jussieu, 75252 Paris cedex 05 (France)

    2011-05-15

    Research Highlights: > Up. Dog./Oxf. sequence is investigated for radioactive waste disposal feasibilities. > Marine carbonates suffered isotopic exchanges with meteoric water. > Modelling shows that very low W/R ratio can explain isotopic changes in clay layer. > Higher W/R ratio are needed to reach isotopic changes in carbonated layers. > Confirmed barrier property of clay layer was probably reached during early burial. - Abstract: Upper Dogger to Oxfordian Formations in the eastern part of the Paris basin (France) are currently being investigated by the French nuclear waste management agency (Andra), testing the feasibility of long-term deep nuclear waste disposal in the Callovo-Oxfordian claystones. Characterising the hydrogeological behaviour of the Callovo-Oxfordian claystones is, therefore, essential in evaluating its potential as a geological barrier. In order to evaluate and quantify water/rock interactions experienced over geological time by these Formations, bulk carbonate {delta}{sup 13}C and {delta}{sup 18}O were measured and calculations of water-rock ratios were used to explain carbonate-{delta}{sup 18}O changes. Meteoric porewater and a maximum temperature reached of about 40 deg. C were considered. The Jurassic marine carbonate {delta}{sup 13}C was preserved in the Callovo-Oxfordian claystones and in the overlying limestones (-0.28 per mille to 3.39 per mille/PDB), while the {delta}{sup 18}O values are lower by 0-5 per mille (-6.25 per mille to -1.32 per mille/PDB). Calculations show that Upper Dogger and Oxfordian Limestone {delta}{sup 18}O data: (i)have random-like distribution through theoretical {delta}{sup 18}O-W/R curves and (ii)suggest that water/rock ratios (0.08-0.4) needed to explain {delta}{sup 18}O changes are higher by a factor of about 2-20 compared to the present-day water/rock ratio. These features indicate advection in both aquifers. According to the history of the Paris basin, this hydrogeological behaviour could have been

  20. Influence of Plio-Pleistocene basin hydrology on the Turkana hominin enamel carbonate δ(18)O values.

    Science.gov (United States)

    Quinn, Rhonda L

    2015-09-01

    Stable oxygen isotopes of hominin enamel carbonate (δ(18)OEC) provide a window into aspects of past drinking behavior and diet, body size, breastfeeding and weaning, mobility, and paleoclimate. It is tempting to compare all hominins across time and space in order to gauge species-level adaptations to changing environments and niche separation between those living sympatrically. Basinal, sub-basinal, and micro-environmental differences, however, may exert an influence on variation in enamel carbonate isotopic values that must be reconciled before hominin species across Africa can be meaningfully compared. Plio-Pleistocene Turkana hominin δ(18)OEC values show a considerable spread, potentially revealing many intrinsic and extrinsic contributing factors operating on different scales. In this study, I examine Turkana hominin δ(18)OEC values relative to identity (taxon, tooth type and number, body size of taxon), dietary (δ(13)C value, Turkana coeval and modern mammalian δ(18)OEC values), and contextual (time, depositional environment) information of each specimen and collection locality and discuss various potential influences. Turkana hominin δ(18)OEC values may primarily reflect differences in imbibed water sources (lake vs. river) as a function of evolving basin hydrology. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Procedure for rapid determination of δ15N and δ18O values of nitrate: development and application to an irrigated rice paddy watershed.

    Science.gov (United States)

    Yada, Saeko; Nakajima, Yasuhiro; Itahashi, Sunao; Asada, Kei; Yoshikawa, Seiko; Eguchi, Sadao

    2016-01-01

    The dual isotope approach using the stable isotope ratios of nitrate nitrogen (δ(15)N(NO3)) and oxygen (δ(18)O(NO3)) is a strong tool for identifying the history of nitrate in various environments. Basically, a rapid procedure for determining δ(15)N(NO3) and δ(18)O(NO3) values is required to analyze many more samples quickly and thus save on the operational costs of isotope-ratio mass spectrometry (IRMS). We developed a new rapid procedure to save time by pre-treating consecutive samples of nitrous oxide microbially converted from nitrate before IRMS determination. By controlling two six-port valves of the pre-treatment system separately, IRMS determination of the current sample and backflush during the next sample pre-treatment period could be conducted simultaneously. A set of 89 samples was analyzed precisely during a 25-h continuous run (17 min per sample), giving the fastest reported processing time, and simultaneously reducing liquid nitrogen and carrier helium gas consumption by 35%. Application of the procedure to an irrigated rice paddy watershed suggested that nitrate concentrations in river waters decreased in a downstream direction, mainly because of the mixing of nitrate from different sources, without distinct evidence of denitrification. Our procedure should help with more detailed studies of nitrate formation processes in watersheds.

  2. Gas Hydrate Occurrence Inferred from Dissolved Cl− Concentrations and δ18O Values of Pore Water and Dissolved Sulfate in the Shallow Sediments of the Pockmark Field in Southwestern Xisha Uplift, Northern South China Sea

    Directory of Open Access Journals (Sweden)

    Min Luo

    2014-06-01

    Full Text Available Deep-water pockmarks are frequently accompanied by the occurrence of massive gas hydrates in shallow sediments. A decline in pore-water Cl− concentration and rise in δ18O value provide compelling evidence for the gas hydrate dissociation. Mega-pockmarks are widely scattered in the southwestern Xisha Uplift, northern South China Sea (SCS. Pore water collected from a gravity-core inside of a mega-pockmark exhibits a downward Cl− concentration decrease concomitant with an increase in δ18O value at the interval of 5.7–6.7 mbsf. Concentrations of Cl−, Na+, and K+ mainly cluster along the seawater freshening line without distinct Na+ enrichment and K+ depletion. Thus, we infer that the pore water anomalies of Cl− concentrations and δ18O values are attributed to gas hydrate dissociation instead of clay mineral dehydration. Moreover, the lower δ18O values of sulfate in the target core (C14 than those in the reference core (C9 may be associated with the equilibrium oxygen fractionation during sulfate reduction between sulfate and the relatively 18O-depleted ambient water resulting from gas hydrate formation. The gas hydrate contents are estimated to be 6%–10% and 7%–15%, respectively, according to the offset of Cl− concentrations and δ18O values from the baselines. This pockmark field in southwestern Xisha Uplift is likely to be a good prospective area for the occurrence of gas hydrate in shallow sediments.

  3. Automated calibration of laser spectrometer measurements of δ18 O and δ2 H values in water vapour using a Dew Point Generator.

    Science.gov (United States)

    Munksgaard, Niels C; Cheesman, Alexander W; Gray-Spence, Andrew; Cernusak, Lucas A; Bird, Michael I

    2018-06-30

    Continuous measurement of stable O and H isotope compositions in water vapour requires automated calibration for remote field deployments. We developed a new low-cost device for calibration of both water vapour mole fraction and isotope composition. We coupled a commercially available dew point generator (DPG) to a laser spectrometer and developed hardware for water and air handling along with software for automated operation and data processing. We characterised isotopic fractionation in the DPG, conducted a field test and assessed the influence of critical parameters on the performance of the device. An analysis time of 1 hour was sufficient to achieve memory-free analysis of two water vapour standards and the δ 18 O and δ 2 H values were found to be independent of water vapour concentration over a range of ≈20,000-33,000 ppm. The reproducibility of the standard vapours over a 10-day period was better than 0.14 ‰ and 0.75 ‰ for δ 18 O and δ 2 H values, respectively (1 σ, n = 11) prior to drift correction and calibration. The analytical accuracy was confirmed by the analysis of a third independent vapour standard. The DPG distillation process requires that isotope calibration takes account of DPG temperature, analysis time, injected water volume and air flow rate. The automated calibration system provides high accuracy and precision and is a robust, cost-effective option for long-term field measurements of water vapour isotopes. The necessary modifications to the DPG are minor and easily reversible. Copyright © 2018 John Wiley & Sons, Ltd.

  4. Seasonal Climate Profiles of an Ice-free Arctic Based on Intra-ring Analyses of δ18O Value in Fossil Wood

    Science.gov (United States)

    Schubert, B.; Jahren, A. H.

    2017-12-01

    Arctic sea ice thickness and extent are projected to continue their substantial decline during this century, with an 80% reduction in sea-ice extent by 2050. While there is a clear relationship between mean annual temperature (MAT) and the concentration of atmospheric carbon dioxide (pCO2) across both glacial and interglacial periods, data on seasonal fluctuations is limited. Here we report seasonal temperature estimates for the Arctic during the ice-free conditions of the late early to middle Eocene based upon exquisitely preserved, mummified wood collected from Banks Island, Northwest Territories, Canada ( 74 oN). Annual growth rings identified in the wood specimens were subdivided by hand at sub-millimeter resolution and cellulose was extracted from each sub-sample for determination of stable oxygen isotope (δ18O) value (n = 81). The data reveal a consistent, cyclic pattern of decreasing and increasing δ18O value up to 3‰ across growth rings that was consistent with patterns observed in other modern and fossil wood, including from other high latitude sites. From these data we quantified cold month and warm month seasonal temperatures using a previously published model (Schubert and Jahren, 2015, QSR, 125: 1-14). Our calculations revealed low overall seasonality in the Arctic during the Eocene with above-freezing winters and mild summers, consistent with the presence of high biomass temperate rainforests. These results highlight the importance of warm winters in maintaining ice-free conditions in the Arctic and suggest that increased winter temperatures in today's Arctic in response to rising pCO2 will be of particular importance for Arctic ice-loss.

  5. Growth Rates, Stable Oxygen Isotopes (18O), and Strontium (Sr/Ca) Composition in Two Species of Pacific Sclerosponges (Acanthocheatetes wellsi and Astrosclera willeyana) with 18O Calibration and Application to Paleoceanography

    Energy Technology Data Exchange (ETDEWEB)

    Grottoli, A.; Adkins, J; Panero, W; Reaman, D; Moots, K

    2010-01-01

    The isotopic and elemental composition of sclerosponge skeletons is used to reconstruct paleoceanographic records. Yet few studies have systematically examined the natural variability in sclerosponge skeletal {delta}{sup 18}O, growth, and Sr/Ca, and how that may influence the interpretation of sclerosponge proxy records. Here, we analyzed short records in seven specimens of Acanthocheatetes wellsi (high-Mg calcite, 21 mol% Mg) from Palau, four A. wellsi (high-Mg calcite, 21 mol% Mg) from Saipan, and three Astrosclera willeyana (aragonite) sclerosponges from Saipan, as well as one long record in an A. wellsi specimen from Palau spanning 1945-2001.5. In Saipan, species-specific and mineralogical effects appear to have a negligible effect on sclerosponge {delta}{sup 18}O, facilitating the direct comparison of {delta}{sup 18}O records between species at a given location. At both sites, A. wellsi {delta}{sup 18}O and growth rates were sensitive to environmental conditions, but Sr/Ca was not sensitive to the same conditions. High-resolution {delta}{sup 18}O analyses confirmed this finding as both A. wellsi and A. willeyana deposited their skeleton in accordance with the trends in isotopic equilibrium with seawater, though with a 0.27{per_thousand} offset in the case of A. willeyana. In the high-Mg-calcite species A. wellsi, Mg may be interfering with Sr incorporation into the skeleton. On multidecadal timescales, A. wellsi sclerosponge {delta}{sup 18}O in Palau tracked the Southern Oscillation Index variability post-1977, but not pre-1977, coincident with the switch in the Pacific Decadal Oscillation (PDO) at {approx}1976. This suggests that water mass circulation in the region is influenced by El Nino-Southern Oscillation variability during positive PDO phases, but not during negative ones.

  6. {delta}{sup 15}N of seagrass leaves for monitoring anthropogenic nutrient increases in coral reef ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Yamamuro, M.; Kayanne, H.; Yamano, H

    2003-04-01

    In a coral reef environment, a slight increase in dissolved inorganic nitrogen (DIN;{>=}1.0 {mu}M) can alter the ecosystem via macroalgal blooms. We collected seagrass leaves from the tropical and subtropical Pacific Ocean in five countries and examined the interactions between nutrient concentrations (C, N, P), molar ratios of nutrients, and {delta}{sup 15}N to find a possible indicator of the DIN conditions. Within most sites, the concentrations of nutrients and their molar ratios showed large variations owing to species-specific values. On the other hand, almost identical {delta}{sup 15}N values were found in seagrass leaves of several species at each site. The correlations between {delta}{sup 15}N and nutrient concentrations and between {delta}{sup 15}N and molar ratios of nutrients suggested that nutrient availability did not affect the {delta}{sup 15}N value of seagrass leaves by altering the physiological condition of the plants. Increases in {delta}{sup 15}N of seagrass leaves mostly matched increases in DIN concentrations in the bottom water. We suggest that {delta}{sup 15}N in seagrass leaves can be a good tool to monitor time-integrated decrease/increase of DIN concentrations at a site, both in the water column and the interstitial water.

  7. Using delta15N- and delta18O-values to identify nitrate sources in karst ground water, Guiyang, southwest China.

    Science.gov (United States)

    Liu, Cong-Qiang; Li, Si-Liang; Lang, Yun-Chao; Xiao, Hua-Yun

    2006-11-15

    Nitrate pollution of the karstic groundwater is an increasingly serious problem with the development of Guiyang, the capital city of Guizhou Province, southwest China. The higher content of NO3- in groundwater compared to surface water during both summer and winter seasons indicates that the karstic groundwater system cannot easily recover once contaminated with nitrate. In order to assess the sources and conversion of nitrate in the groundwater of Guiyang, we analyzed the major ions, delta(15)N-NH4+, delta(15)N-NO3-, and delta(18)O-NO3- in surface and groundwater samples collected during both summer and winter seasons. The results show that nitrate is the major dominant species of nitrogen in most water samples and there is a big variation of nitrate sources in groundwater between winter and summer season, due to fast response of groundwater to rain or surface water in the karst area. Combined with information on NO3- /Cl-, the variations of the isotope values of nitrate in the groundwater show a mixing process of multiple sources of nitrate, especially in the summer season. Chemical fertilizer and nitrification of nitrogen-containing organic materials contribute nitrate to suburban groundwater, while the sewage effluents and denitrification mainly control the nitrate distribution in urban groundwater.

  8. Coral skeletal {delta}{sup 15}N reveals isotopic traces of an agricultural revolution

    Energy Technology Data Exchange (ETDEWEB)

    Marion, Guy S. [Department of Biological Sciences, Stanford University, Stanford, CA 94305 (United States)]. E-mail: g.marion@uq.edu.au; Dunbar, Robert B. [Department of Geological and Environmental Sciences, Stanford University, Stanford, CA 94305 (United States); Mucciarone, David A. [Department of Geological and Environmental Sciences, Stanford University, Stanford, CA 94305 (United States); Kremer, James N. [Department of Marine Sciences, University of Connecticut at Avery Point, Groton, CT 06340 (United States); Lansing, J. Stephen [Department of Anthropology, University of Arizona, Tucson, AZ 85721 (United States); Arthawiguna, Alit [Installation for Agricultural Research (IP 2TP), Kotak Pos 3480, Denpasar, Bali (Indonesia)

    2005-09-01

    This study introduces a new method of tracing the history of nutrient loading in coastal oceans via {delta}{sup 15}N analysis of organic nitrogen preserved in the skeleton of the massive Porites coral. Four coral cores were collected in Bali, Indonesia, from reefs exposed to high levels of fertilizers in agricultural run-off, from lagoonal corals impacted by sewage, and from a reef located 30 km offshore. Skeletal {delta}{sup 15}N in the agriculturally exposed coral declined from 10.7 {+-} 0.4 per mille in 1970-1971, when synthetic fertilizers (-0.8 per mille {+-} 0.2 per mille ) were introduced to Bali, to a depleted 'anthropogenic' baseline of 3.5 per mille {+-} 0.4% in the mid-1990s. {delta}{sup 15}N values were negatively correlated with rainfall, suggesting that marine {delta}{sup 15}N lowers during flood-born influxes of waste fertilizers. Reef cores exposed to untreated sewage in terrestrial discharge were enriched (7.8 and 7.3 {+-} 0.4 per mille ), while the offshore core reflected background oceanic signals (6.2 {+-} 0.4 per mille). {delta}{sup 15}N, N concentration, and C:N systematics indicate that the N isotopic composition of skeletal organic matter was generally well preserved over 30 years. We suggest that skeletal organic {delta}{sup 15}N can serve as a recorder of past nitrogen sources. In Bali, this tracer suggests that the intensification of Western style agricultural practices since 1970 are contributing to the degradation of coastal coral reefs.

  9. Processes affecting δ34S and δ18O values of dissolved sulfate in alluvium along the Canadian River, central Oklahoma, USA

    Science.gov (United States)

    Tuttle, Michele L.W.; Breit, George N.; Cozzarelli, Isabelle M.

    2009-01-01

    The δ34S and δ18O values for dissolved sulfate in groundwater are commonly used in aquifer studies to identify sulfate reservoirs and describe biogeochemical processes. The utility of these data, however, often is compromised by mixing of sulfate sources within reservoirs and isotope fractionation during sulfur redox cycling. Our study shows that, after all potential sulfate sources are identified and isotopically characterized, the δ34SSO4 and δ18OSO4 values differentiate processes such as sulfate-source mixing, sulfide oxidation, barite dissolution, and organosulfur decomposition. During bacterial reduction of sulfate, the values reflect kinetic sulfur isotope fractionation and exchange of oxygen isotopes between sulfate and water. Detailed analysis of the chemistry (Cl and SO4 concentrations) and isotopic composition (δ2HH2Oand δ18OH2O) of groundwater in an alluvial aquifer in Central Oklahoma, USA allowed the identification of five distinct end members that supply water to the aquifer (regional groundwater flowing into the study area, river water, leachate from a closed landfill that operated within the site, rain, and surface runoff). The δ34SSO4 and δ18OSO4 values in each end member differentiated three sources of sulfate: sulfate dissolved from Early to Late Permian rocks within the drainage basin (δ34SSO4 = 8–12‰ and δ18OSO4 = 10‰), iron sulfides oxidized by molecular oxygen during low water-table levels (δ34SSO4 = − 16‰ and δ18OSO4 = 10‰), and organosulfur compounds (predominately ester sulfates) from decomposition of vegetation on the surface and from landfill trash buried in the alluvium (δ34SSO4 = 8‰ and δ18OSO4 = 6‰). During bacterial reduction of these sulfate sources, similar isotope fractionation processes are recorded in the parallel trends of increasing δ34SSO4 and δ18OSO4 values. When extensive reduction occurs, the kinetic sulfur isotope fractionation (estimated by εH2S–SO4 = − 23

  10. Three New Offset {delta}{sup 11}B Isotope Reference Materials for Environmental Boron Isotope Studies

    Energy Technology Data Exchange (ETDEWEB)

    Rosner, M. [BAM Federal Institute for Materials Research and Testing, Berlin (Germany); IsoAnalysis UG, Berlin (Germany); Vogl, J. [BAM Federal Institute for Materials Research and Testing, Berlin (Germany)

    2013-07-15

    The isotopic composition of boron is a well established tool in various areas of science and industry. Boron isotope compositions are typically reported as {delta}{sup 11}B values which indicate the isotopic difference of a sample relative to the isotope reference material NIST SRM 951. A significant drawback of all of the available boron isotope reference materials is that none of them covers a natural boron isotope composition apart from NIST SRM 951. To fill this gap of required {delta}{sup 11}B reference materials three new solution boric acid reference materials were produced, which cover 60 per mille of the natural boron isotope variation (-20 to 40 per mille {delta}{sup 11}B) of about 100 per mille . The new reference materials are certified for their {delta}{sup 11}B values and are commercially available through European Reference Materials (http://www.erm-crm.org). The newly produced and certified boron isotope reference materials will allow straightforward method validation and quality control of boron isotope data. (author)

  11. {sup 2}H NMR and {sup 13}C-IRMS analyses of acetic acid from vinegar, {sup 18}O-IRMS analysis of water in vinegar: International collaborative study report

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Freddy [Eurofins Scientific Analytics, BP42301, 44323 Nantes (France); Jamin, Eric [Eurofins Scientific Analytics, BP42301, 44323 Nantes (France)

    2009-09-01

    An international collaborative study of isotopic methods applied to control the authenticity of vinegar was organized in order to support the recognition of these procedures as official methods. The determination of the {sup 2}H/{sup 1}H ratio of the methyl site of acetic acid by SNIF-NMR (site-specific natural isotopic fractionation-nuclear magnetic resonance) and the determination of the {sup 13}C/{sup 12}C ratio, by IRMS (isotope ratio mass spectrometry) provide complementary information to characterize the botanical origin of acetic acid and to detect adulterations of vinegar using synthetic acetic acid. Both methods use the same initial steps to recover pure acetic acid from vinegar. In the case of wine vinegar, the determination of the {sup 18}O/{sup 16}O ratio of water by IRMS allows to differentiate wine vinegar from vinegars made from dried grapes. The same set of vinegar samples was used to validate these three determinations. The precision parameters of the method for measuring {delta}{sup 13}C (carbon isotopic deviation) were found to be similar to the values previously obtained for similar methods applied to wine ethanol or sugars extracted from fruit juices: the average repeatability (r) was 0.45 per mille , and the average reproducibility (R) was 0.91 per mille . As expected from previous in-house study of the uncertainties, the precision parameters of the method for measuring the {sup 2}H/{sup 1}H ratio of the methyl site were found to be slightly higher than the values previously obtained for similar methods applied to wine ethanol or fermentation ethanol in fruit juices: the average repeatability was 1.34 ppm, and the average reproducibility was 1.62 ppm. This precision is still significantly smaller than the differences between various acetic acid sources ({delta}{sup 13}C and {delta}{sup 18}O) and allows a satisfactory discrimination of vinegar types. The precision parameters of the method for measuring {delta}{sup 18}O were found to be similar

  12. Influence of different organic fertilizers on quality parameters and the delta(15)N, delta(13)C, delta(2)H, delta(34)S, and delta(18)O values of orange fruit (Citrus sinensis L. Osbeck).

    Science.gov (United States)

    Rapisarda, Paolo; Camin, Federica; Fabroni, Simona; Perini, Matteo; Torrisi, Biagio; Intrigliolo, Francesco

    2010-03-24

    To investigate the influence of different types of fertilizers on quality parameters, N-containing compounds, and the delta(15)N, delta(13)C, delta(2)H, delta (34)S, and delta(18)O values of citrus fruit, a study was performed on the orange fruit cv. 'Valencia late' (Citrus sinensis L. Osbeck), which was harvested in four plots (three organic and one conventional) located on the same farm. The results demonstrated that different types of organic fertilizers containing the same amount of nitrogen did not effect important changes in orange fruit quality parameters. The levels of total N and N-containing compounds such as synephrine in fruit juice were not statistically different among the different treatments. The delta(15)N values of orange fruit grown under fertilizer derived from animal origin as well as from vegetable compost were statistically higher than those grown with mineral fertilizer. Therefore, delta(15)N values can be used as an indicator of citrus fertilization management (organic or conventional), because even when applied organic fertilizers are of different origins, the natural abundance of (15)N in organic citrus fruit remains higher than in conventional ones. These treatments also did not effect differences in the delta(13)C, delta(2)H, delta(34)S, and delta(18)O values of fruit.

  13. Identification of nitrate sources in Taihu Lake and its major inflow rivers in China, using δ(15)N-NO(3)(-) and δ(18)O-NO(3)(-) values.

    Science.gov (United States)

    Chen, Zi-Xiang; Liu, Guang; Liu, Wei-Guo; Lam, Michael H W; Liu, Gui-Jian; Yin, Xue-Bin

    2012-01-01

    In the present study, δ(15)N and δ(18)O-NO(3)(-) values, as well as concentrations of some major ion tracers were determined in seasonal water samples from Taihu Lake and major watersheds to investigate the temporal and spatial variations of nitrate sources and assess the underlying nitrogen (N) biogeochemistry process. The results lead to the conclusion that the nitrate concentrations in Taihu Lake are lower in summer than that in winter due to the dilution effect of wet deposition. In winter, sewage and manure were the primary nitrate sources in major inflow rivers and North Taihu Lake (NTL), while nitrate sources in East Taihu Lake (ETL) probably derived from soil organic N. In summer, atmospheric deposition and sewage/manure inputs appear to play an important role in controlling the distribution of nitrates in the whole lake. The δ(18)O-NO(3)(-) values suggest that the nitrate produced from microbial nitrification is another major nitrate source during both winter and summer months. The variations in isotopic values in nitrate suggest denitrification enriched the heavier isotopes of nitrate in NTL in winter and in ETL in summer.

  14. Determination of wine authenticity and geographical origin by measuring non-exchangeable hydrogen stable isotopes in wine ethanol with EIM-IRMS® methodology in combination with δ18O values obtained from wine water.

    Science.gov (United States)

    Smajlovic, Ivan; Glavanovic, Mirko; Sparks, Kimberlee L.; Sparks, Jed P.; Jovic, Slobodan

    2014-05-01

    Wine consumption has grown significantly in the last two decades, with the United States being the leading consumer of wine in the world. It is also the second largest wine producer and importer after the European Union, which consists of 27 European countries. The world has seen a significant increase in production from new world countries, especially the United States, Australia and Chile, and wine imports have grown significantly with this globalization. The quality and authenticity of products have become critical concerns. With the amount of wine being imported the need for verifying wine authenticity and understanding procedures used in wine making has become more important than ever. Understanding the origin of consumed wine in rapidly expanding global economy has become fundamental in order to control quality and protect consumers. In our previous scientific work we have shown that EIM-IRMS®, Ethanol Isotope Measurement - Isotope Ratio Mass Spectrometry (EIM-IRMS®), is capable of providing unique molecular fingerprint that cannot be reproduced or counterfeited. Today we know that δ18O value from the wine water is one of the most important parameters which can give information about wine geographical origin. Earlier we have suggested that grape juice or grape pulp is a closed biochemical system in which all chemical compounds stand in dynamic equilibrium and are in direct connection with each other. Taking that into consideration we have concluded that if system is genuine and if no water, or no sugar has been added to the grape must or grape juice prior to alcoholic fermentation, then ethanol which is made in process of alcoholic fermentation will have specific δD value of non-exchangeable hydrogen stable isotopes which will be in range from -205 to -215 ‰ vs. V-SMOW. In this work we will show that this value, which we named δDn (non-exchangeable hydrogen stable isotopes in ethanol), is very important because it can support or refute conclusions

  15. Effects of variation in background mixing ratios of N2, O2, and Ar on the measurement of δ18O-H2O and δ2H-H2O values by cavity ring-down spectroscopy

    Science.gov (United States)

    Johnson, Jennifer E.; Rella, Chris W.

    2017-08-01

    Cavity ring-down spectrometers have generally been designed to operate under conditions in which the background gas has a constant composition. However, there are a number of observational and experimental situations of interest in which the background gas has a variable composition. In this study, we examine the effect of background gas composition on a cavity ring-down spectrometer that measures δ18O-H2O and δ2H-H2O values based on the amplitude of water isotopologue absorption features around 7184 cm-1 (L2120-i, Picarro, Inc.). For background mixtures balanced with N2, the apparent δ18O values deviate from true values by -0.50 ± 0.001 ‰ O2 %-1 and -0.57 ± 0.001 ‰ Ar %-1, and apparent δ2H values deviate from true values by 0.26 ± 0.004 ‰ O2 %-1 and 0.42 ± 0.004 ‰ Ar %-1. The artifacts are the result of broadening, narrowing, and shifting of both the target absorption lines and strong neighboring lines. While the background-induced isotopic artifacts can largely be corrected with simple empirical or semi-mechanistic models, neither type of model is capable of completely correcting the isotopic artifacts to within the inherent instrument precision. The development of strategies for dynamically detecting and accommodating background variation in N2, O2, and/or Ar would facilitate the application of cavity ring-down spectrometers to a new class of observations and experiments.

  16. C{sub 4} plant isotopic composition ({delta}{sup 13}C) evidence for urban CO{sub 2} pollution in the city of Cotonou, Benin (West Africa)

    Energy Technology Data Exchange (ETDEWEB)

    Kelome, Nelly C.; Leveque, Jean; Andreux, Francis; Milloux, Marie-Jeanne [UMR Microbiologie et Geochimie des Sols INRA, Universite de Bourgogne, Centre des Sciences de la Terre, 6 Bd Gabriel, 21000 Dijon (France); Oyede, Lucien-Marc [Departement des Sciences de la Terre, Universite d' Abomey-Calavi, 01 B.P. 526, Cotonou (Benin)

    2006-08-01

    The carbon isotopic composition ({delta}{sup 13}C) of plants can reveal the isotopic carbon content of the atmosphere in which they develop. The {delta}{sup 13}C values of air and plants depend on the amount of atmospheric fossil fuel CO{sub 2}, which is chiefly emitted in urban areas. A new indicator of CO{sub 2} pollution is tested using the {delta}{sup 13}C variation in a C{sub 4} grass: Eleusine indica. A range of about 4%% delta units was observed at different sites in Cotonou, the largest city in the Republic of Benin. The highest {delta}{sup 13}C values, from -12%% to -14%%, were found in low traffic zones; low {delta}{sup 13}C values, from -14%% to -16%%, were found in high traffic zones. The amount of fossil fuel carbon assimilated by plants represented about 20% of the total plant carbon content. An overall decrease in plant {delta}{sup 13}C values was observed over a four-year monitoring period. This decrease was correlated with increasing vehicle traffic. The {delta}{sup 13}C dataset and the corresponding geographical database were used to map and define zones of high and low {sup 13}C-depleted CO{sub 2} emissions in urban and sub-urban areas. The spatial distribution follows dominant wind directions, with the lowest emission zones found in the southwest of Cotonou. High CO{sub 2} emissions occurred in the north, the east and the center, providing evidence of intense anthropogenic activity related to industry and transportation. (author)

  17. C{sub 4} plant isotopic composition ((delta){sup 13}C) evidence for urban CO{sub 2} pollution in the city of Cotonou, Benin (West Africa)

    Energy Technology Data Exchange (ETDEWEB)

    Kelome, Nelly C.; Leveque, Jean; Andreux, Francis; Milloux, Marie-Jeanne [UMR Microbiologie et Geochimie des Sols INRA, Universite de Bourgogne, Centre des Sciences de la Terre, 6 Bd Gabriel, 21000 Dijon (France); Oyede, Lucien-Marc [Departement des Sciences de la Terre, Universite d' Abomey-Calavi, 01 B.P. 526, Cotonou (Benin)

    2006-08-01

    The carbon isotopic composition ((delta){sup 13}C) of plants can reveal the isotopic carbon content of the atmosphere in which they develop. The (delta){sup 13}C values of air and plants depend on the amount of atmospheric fossil fuel CO{sub 2}, which is chiefly emitted in urban areas. A new indicator of CO{sub 2} pollution is tested using the (delta){sup 13}C variation in a C{sub 4} grass: Eleusine indica. A range of about 4%% delta units was observed at different sites in Cotonou, the largest city in the Republic of Benin. The highest (delta){sup 13}C values, from -12%% to -14%%, were found in low traffic zones; low (delta){sup 13}C values, from -14%% to -16%%, were found in high traffic zones. The amount of fossil fuel carbon assimilated by plants represented about 20% of the total plant carbon content. An overall decrease in plant (delta){sup 13}C values was observed over a four-year monitoring period. This decrease was correlated with increasing vehicle traffic. The (delta){sup 13}C dataset and the corresponding geographical database were used to map and define zones of high and low {sup 13}C-depleted CO{sub 2} emissions in urban and sub-urban areas. The spatial distribution follows dominant wind directions, with the lowest emission zones found in the southwest of Cotonou. High CO{sub 2} emissions occurred in the north, the east and the center, providing evidence of intense anthropogenic activity related to industry and transportation. (author)

  18. The Use of {delta}{sup 37}CL to Explain Origin and Production of Salt from the Saline Spring 'Fonte da Pipa' in Rio Maior (Central Portugal)

    Energy Technology Data Exchange (ETDEWEB)

    Eggenkamp, H. G.M.; Marques, J. M. [Centro de Petrologia e Geoquimica, Instituto Superior Tecnico, Lisbon (Portugal); Graca, H. [Centro Hospitalar das Caldas da Rainha, Caldas da Rainha (Portugal)

    2013-07-15

    Salt extraction in Rio Maior (Central Portugal) is unique in the sense that salt is exploited from a very saline (134 g/L NaCl) terrestrial spring. This spring receives its salt through meteoric water circulation from nearby hills along a shallow salt diapir. This is shown using {delta}{sup 37}Cl, as the composition in dug wells between the mountains and the saline spring is comparable, while {delta}{sup 37}Cl in a well to the east is significantly different. Unlike seawater this spring contains nearly pure NaCl, giving us the opportunity to determine {delta}{sup 37}Cl values in a natural salt precipitating system beyond the point where (in seawater) potassium and magnesium chlorides start to precipitate. {delta}{sup 37}Cl values were determined from brines and by precipitating salt in salt pans with different evaporation stages. Fractionation of up to 1 per mille was found. To complement these natural data, evaporation/precipitation experiments are currently being conducted under controlled laboratory conditions. First results of these experiments indicate that during continued evaporation and precipitation {delta}{sup 37}Cl continues to decrease. (author)

  19. Salinity information in coral δ18O records

    Science.gov (United States)

    Conroy, J. L.; Thompson, D. M.; Dassié, E. P.; Stevenson, S.; Konecky, B. L.; DeLong, K. L.; Sayani, H. R.; Emile-Geay, J.; Partin, J. W.; Abram, N. J.; Martrat, B.

    2017-12-01

    Coral oxygen isotopic ratios (δ18O) are typically utilized to reconstruct sea surface temperature (SST), or SST-based El Niño-Southern Oscillation metrics (e.g., NIÑO3.4), despite the influence of both SST and the oxygen isotopic composition of seawater (δ18Osw) on coral δ18O. The ideal way to isolate past δ18Osw variations is to develop independent and univariate SST and δ18Osw responders, for instance, via paired coral δ18O and Sr/Ca analyses. Nonetheless, many coral δ18O records without paired Sr/Ca records already exist in the paleoclimatic literature, and these may be able to provide some insight into past δ18Osw and salinity changes due to the nature of the significant positive relationship between instrumental salinity and δ18Osw. Here we use coral δ18O records from the new PAGES Iso2k database to assess the regions in which coral δ18O has the greatest potential to provide salinity information based on the strength of the relationship between instrumental salinity and coral δ18O values. We find from annual pseudocoral similations that corals in the western tropical Pacific share a substantial fraction of their variance with δ18Osw rather than SST. In contrast, in the Indian Ocean and eastern tropical Pacific it is SST that predominantly explains coral δ18O variance. In agreement with this variance decomposition, we find that coral δ18O time series from the western tropical Pacific are significantly correlated with mid to late 20th century salinity. However, variations in the strength of the δ18Osw-salinity relationship across the western tropical Pacific will likely have a significant influence on coral δ18O-based salinity reconstructions. Additionally, in some cases a strong, negative correlation between SST and δ18Osw might not allow their influences to be adequately separated in coral δ18O records without the use of coupled Sr/Ca estimates of the temperature contribution. Overall, we find a range of modern salinity and SST

  20. Metabolic origin of the {delta}{sup 13}C of respired CO{sub 2} in roots of Phaseolus vulgaris

    Energy Technology Data Exchange (ETDEWEB)

    Bathellier, C.; Tcherkez, G.; Cornic, G.; Ghashghaie, J. [Laboratoire d' Ecologie, Systematique et Evolution - ESE, CNRS-UMR 8079 - IFR 87, Batiment 362, Universite Paris-Sud, 91405-Orsay Cedex (France); Tcherkez, G. [Plateforme Metabolisme-Metabolome, IFR87 La Plante et son Environnement, Institut de Biotechnologie des Plantes, Batiment 630, Universite Paris-Sud, 91405-Orsay Cedex (France); Bligny, R.; Gout, E. [Laboratoire de Physiologie Cellulaire Vegetale CEA-Grenoble 17, rue des Martyrs, 38054 Grenoble Cedex 9 (France)

    2009-07-01

    - Root respiration is a major contributor to soil CO{sub 2} efflux, and thus an important component of ecosystem respiration. But its metabolic origin, in relation to the carbon isotope composition ({delta}{sup 13}C), remains poorly understood. - Here, {sup 13}C analysis was conducted on CO{sub 2} and metabolites under typical conditions or under continuous darkness in French bean (Phaseolus vulgaris) roots. {sup 13}C contents were measured either under natural abundance or following pulse-chase labeling with {sup 13}C-enriched glucose or pyruvate, using isotope ratio mass spectrometer (IRMS) and nuclear magnetic resonance (NMR) techniques. - In contrast to leaves, no relationship was found between the respiratory quotient and the {delta}{sup 13}C of respired CO{sub 2}, which stayed constant at a low value (c. -27.5 per thousand) under continuous darkness. With labeling experiments, it is shown that such a pattern is explained by the {sup 13}C-depleting effect of the pentose phosphate pathway; and the involvement of the Krebs cycle fueled by either the glycolytic input or the lipid/protein recycling. The anaplerotic phosphoenolpyruvate carboxylase (PEPc) activity sustained glutamic acid (Glu) synthesis, with no net effect on respired CO{sub 2}. - These results indicate that the root {delta}{sup 13}C signal does not depend on the availability of root respiratory substrates and it is thus plausible that, unless the {sup 13}C photosynthetic fractionation varies at the leaf level, the root {delta}{sup 13}C signal hardly changes under a range of natural environmental conditions. (authors)

  1. The use of 18O as a groundwater tracer in the Marlborough Region

    International Nuclear Information System (INIS)

    Stewart, M.K.

    2006-01-01

    The usefulness of 18 O for monitoring groundwater wells in the Wairau River coastal plain has been investigated by conducting a survey of the wells used for monitoring. The δ 18 O values of the Wairau Aquifer well waters show trends along the lines of flow depending on distance and depth. Near the head of the valley and close to the river, the groundwater has δ 18 O values like that of the Wairau River. With distance from the river and towards the coast, the δ 18 O values of shallow groundwater in the unconfined aquifer become more positive as land surface infiltrating recharge with higher δ 18 O values contributes to the flow. The infiltrating water also carries nitrate and other chemicals to the groundwater. At deeper levels, the groundwater is not affected by water infiltrating through the surface, and retains its Wairau River δ 18 O signature when it rises towards the surface near the coast. However, this conclusion is regarded as preliminary because of the possible temporal variability of the groundwater δ 18 O values. Regular 3-monthly 18 O measurements should be carried out on 8 key wells to substantiate this conclusion. The δ 18 O values of the southern valley aquifer waters indicate that they are sourced from local streams and surface recharge. The Rarangi and Tuamarina aquifers are sourced from local rainfall with δ 18 O of -6.2 permille. (author). 5 refs., 3 figs., 2 tabs

  2. Study of some direct reactions at 00 in 18O+26Mg and 18O+12C systems

    International Nuclear Information System (INIS)

    Payet, J.

    1984-01-01

    Direct transfer reactions induced by a 18 O beam on 12 C and 26 Mg targets, have been studied at the MP tandem (Orsay) with an experimental set up giving the possibility to have angular distributions up to 0 0 . Transfer reactions to discrete levels were analysed in the D.W.B.A. framework. This analysis confirms the interest as a spectroscopic tool of this 0 0 measurements. The ( 18 O, 16 O) and ( 18 O, 20 Ne) reactions were observed up to 40 MeV excitation energy. A diffractionnal model, including the one step direct transfer hypothesis, gives a qualitative agreement with the angular distributions and the energy spectra. A parametrization of a specific small angles development of the transfer amplitudes does not give good results with physical values for the parameters. 32 refs [fr

  3. Automated simultaneous measurement of the δ(13) C and δ(2) H values of methane and the δ(13) C and δ(18) O values of carbon dioxide in flask air samples using a new multi cryo-trap/gas chromatography/isotope ratio mass spectrometry system.

    Science.gov (United States)

    Brand, Willi A; Rothe, Michael; Sperlich, Peter; Strube, Martin; Wendeberg, Magnus

    2016-07-15

    The isotopic composition of greenhouse gases helps to constrain global budgets and to study sink and source processes. We present a new system for high-precision stable isotope measurements of carbon, hydrogen and oxygen in atmospheric methane and carbon dioxide. The design is intended for analyzing flask air samples from existing sampling programs without the need for extra sample air for methane analysis. CO2 and CH4 isotopes are measured simultaneously using two isotope ratio mass spectrometers, one for the analysis of δ(13) C and δ(18) O values and the second one for δ(2) H values. The inlet carousel delivers air from 16 sample positions (glass flasks 1-5 L and high-pressure cylinders). Three 10-port valves take aliquots from the sample stream. CH4 from 100-mL air aliquots is preconcentrated in 0.8-mL sample loops using a new cryo-trap system. A precisely calibrated working reference air is used in parallel with the sample according to the Principle of Identical Treatment. It takes about 36 hours for a fully calibrated analysis of a complete carousel including extractions of four working reference and one quality control reference air. Long-term precision values, as obtained from the quality control reference gas since 2012, account for 0.04 ‰ (δ(13) C values of CO2 ), 0.07 ‰ (δ(18) O values of CO2 ), 0.11 ‰ (δ(13) C values of CH4 ) and 1.0 ‰ (δ(2) H values of CH4 ). Within a single day, the system exhibits a typical methane δ(13) C standard deviation (1σ) of 0.06 ‰ for 10 repeated measurements. The system has been in routine operation at the MPI-BGC since 2012. Consistency of the data and compatibility with results from other laboratories at a high precision level are of utmost importance. A high sample throughput and reliability of operation are important achievements of the presented system to cope with the large number of air samples to be analyzed. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  4. On the Sources of Salinity in Groundwater under Plain Areas. Insights from {delta}{sup 18}O, {delta}{sup 2}H and Hydrochemistry in the Azul River Basin, Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Zabala, M. E.; Varni, M.; Weinzettel, P. [Instituto de Hidrologia de llanuras, Azul (Argentina); Manzano, M. [Technical University of Cartagena (Spain)

    2013-07-15

    The Azul River basin, with some 6200 km{sup 2}, is located in the plains of Buenos Aires Province, Argentina. The Azul River flows along 160 km from the Tandilia Range, in the SW, to the Channel 11, in the NE. Average annual precipitation is 1005 mm (1988-2000); mean reference evapotranspiration is 1090 mm. The geology consists of Miocene to recent sediments, mostly sands and silts with some clay and calcrete layers, overlying crystalline rocks and marine sediments. The water table is shallow and groundwater in the aquifer upper 30 m displays an increasing salinity from SW to NE. The previous hypothesis to explain the salinity was infiltration of evapo-concentrated surface water, as the small soil slope in the northern basin (< 0.2%) induces rainfall accumulation in lowlands, where water evaporates prior to infiltration. But recent chemical and isotopic data reveal two salinity sources: evaporation of recent recharge water, and mixing with old saline groundwater of yet unknown origin. (author)

  5. {Delta}{sup 14}C level of annual plants and fossil fuel derived CO{sub 2} distribution across different regions of China

    Energy Technology Data Exchange (ETDEWEB)

    Xi, X.T.; Ding, X.F.; Fu, D.P. [State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871 (China); Zhou, L.P. [Laboratory for Earth Surface Processes, Department of Geography, Peking University, Beijing 100871 (China); Liu, K.X., E-mail: kxliu@pku.edu.cn [State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871 (China)

    2013-01-15

    The {sup 14}C level in annual plants is a sensitive tracer for monitoring fossil fuel derived CO{sub 2} in the atmosphere. Corn leave samples were selected from different regions of China, including high mountains in the Tibetan Plateau, grassland in Inner Mongolia, and inland and coastal cities during the summer of 2010. The {sup 14}C/{sup 12}C ratio of the samples was measured with the NEC compact AMS system at the Institute of Heavy Ion Physics, Peking University. The fossil fuel derived CO{sub 2} was estimated by comparing the measured {Delta}{sup 14}C values of corn leave samples to background atmospheric {Delta}{sup 14}C level. The influences of topography, meteorological conditions and carbon cycling processes on the fossil fuel derived CO{sub 2} concentration are considered when interpreting the data. Our results show a clear association of the low {Delta}{sup 14}C values with regions where human activities are intensive.

  6. Macroalgal bioindicators (growth, tissue N, {delta}{sup 15}N) detect nutrient enrichment from shrimp farm effluent entering Opunohu Bay, Moorea, French Polynesia

    Energy Technology Data Exchange (ETDEWEB)

    Lin, David T. [Department of Zoology, University of Hawaii at Manoa, 2538 McCarthy Mall, Edmondson 152, Honolulu, HI 96822 (United States)], E-mail: david.t.lin@ucla.edu; Fong, Peggy [Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 621 Young Drive South, Los Angeles, CA 90095 (United States)

    2008-02-15

    Nutrient enrichment from shrimp aquaculture poses an increasing environmental threat due to the industry's projected rapid growth and unsustainable management practices. Traditional methods to monitor impacts emphasize water quality sampling; however, there are many advantages to bioindicators, especially in developing countries. We investigated the usefulness of three bioindicators-growth, tissue nitrogen content and nitrogen stable isotope signature ({delta}{sup 15}N)-in the tropical red macroalga Acanthophora spicifera. Algae were collected, cultured, and deployed in a spatial array around the outflow from a shrimp farm in Moorea, French Polynesia, to detect nitrogenous wastes. All three parameters were highest adjacent to the shrimp farm indicating nutrient enrichment, and {delta}{sup 15}N values confirmed the shrimp farm as the dominant nutrient source (5.63-5.96 per mille ). Isotope ratios proved the most sensitive indicator, as {delta}{sup 15}N signatures were detected at the most distant sites tested, confirming their usefulness in tracing nutrients and mapping the spatial extent of enrichment.

  7. Mahe, Seychelles Stable Isotope (delta 18O) Data for 1846 to 1995

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Seychelles coral oxygen-18 time series, data are monthly values of d18O from July 1846 to February 1995 from a 3-m Porites lutea coral colony collected from Beau...

  8. 18O/16O ratios of the pore water of Baltic Sea sediments

    International Nuclear Information System (INIS)

    Foerstel, H.

    1983-01-01

    Two cores of Baltic Sea sediment were collected in 1975. The 18 O/ 16 O ratio of the water enclosed in the sediment (pore water) was measured after the separation of the liquid from the solid phase. The results may support the discussion about the history of the Baltic Sea. At the top of the core the 18 O/ 16 O ratio of the water represents the oxygen isotope composition of the sea water above. Towards the deeper parts of the sediment, independently of the salt content, the 18 O/ 16 O ratio decreases towards values observed in the precipitation of the surrounding land areas. (author)

  9. Sediment features, macrozoobenthic assemblages and trophic relationships ({delta}{sup 13}C and {delta}{sup 15}N analysis) following a dystrophic event with anoxia and sulphide development in the Santa Giusta lagoon (western Sardinia, Italy)

    Energy Technology Data Exchange (ETDEWEB)

    Magni, P. [CNR-IAMC National Research Council - Institute for Coastal Marine Environment c/o IMC - International Marine Centre, Loc. Sa Mardini, Torregrande, 09072 Oristano (Italy); IMC - International Marine Centre, Loc. Sa Mardini, Torregrande, 09072 Oristano (Italy)], E-mail: paolo.magni@iamc.cnr.it; Rajagopal, S. [Department of Animal Ecology and Ecophysiology, Institute for Water and Wetland Research, Radboud University Nijmegen, Toernooiveld, 6525 ED Nijmegen (Netherlands); Velde, G. van der [Department of Animal Ecology and Ecophysiology, Institute for Water and Wetland Research, Radboud University Nijmegen, Toernooiveld, 6525 ED Nijmegen (Netherlands); National Museum of Natural History Naturalis, P.O. Box 9517, 2300 RA Leiden (Netherlands); Fenzi, G. [IMC - International Marine Centre, Loc. Sa Mardini, Torregrande, 09072 Oristano (Italy); Kassenberg, J. [Department of Animal Ecology and Ecophysiology, Institute for Water and Wetland Research, Radboud University Nijmegen, Toernooiveld, 6525 ED Nijmegen (Netherlands); Vizzini, S.; Mazzola, A. [Dipartimento di Biologia Animale, Universita di Palermo, via Archirafi 18, 90123 Palermo (Italy); Giordani, G. [Dipartimento di Scienze Ambientali, Universita di Parma, Via Usberti 33/A, 43100 Parma (Italy)

    2008-07-01

    Macrozoobenthic assemblages and stable carbon ({delta}{sup 13}C) and nitrogen ({delta}{sup 15}N) isotope values of various primary producers (macroalgae and angiosperms) and consumers (macroinvertebrate filter/suspension feeders, deposit feeders, detritivores/omnivores and carnivores and fishes) were studied in the Santa Giusta lagoon (Sardinia, Italy) before (spring) and after (autumn) a dystrophic event which occurred in the summer of 2004. A few days after the dystrophy, the physico-chemical characteristics of sediments and macrozoobenthic assemblages were also investigated. In the latter occasion, high total organic carbon (3.9%) and organic matter (15.9%) contents of surface sediments went together with peaks in acid-volatile sulphide concentrations. Certain immediate effects were quite extreme, such as the drastic reduction in macrozoobenthos and the massive fish kill in August 2004. Among the macrozoobenthos, there were few individuals of chironomid larvae and Capitella cf. capitata left. However, by October, chironomid larvae were numerous, indicating a lack of predators (e.g. fish) and competitors. In addition, some bivalve species and polychaetes which were absent, or present in small numbers before the event, became relatively numerous. The results are discussed based on a knowledge of the sulphide tolerance of these species. Stable isotope analysis clearly showed that the basal level of the food web for most consumers consisted mainly of macroalgae and sedimentary organic matter, and that the values before and after the dystrophic event were not significantly different from one another. This indicates that the relations among different trophic levels were quickly restored following the dystrophic event.

  10. Petrogenesis of low-δ18O quartz porphyry dykes, Koegel Fontein complex, South Africa

    Science.gov (United States)

    Harris, Chris; Mulder, Kwenidyn; Sarkar, Saheli; Whitehead, Benjamin; Roopnarain, Sherissa

    2018-04-01

    This paper investigates the origin of low-δ18O quartz porphyry dykes associated with the 144-133 Ma Koegel Fontein Igneous Complex, which was intruded during the initial phase of breakup of Africa and South America. The 25-km diameter Rietpoort Granite is the largest and youngest phase of activity, and is roofed by a 10-km diameter pendant of gneiss. Quartz porphyry (QP) dykes, up to 15 m in width, strike NW-SE across the complex. The QP dykes that intruded outside the granite have similar quartz phenocryst δ18O values (average 8.0‰, ± 0.7, n = 33) to the granite (average 8.3 ± 1.0, n = 7). The QP dykes that intruded the roof pendant have quartz phenocrysts with more variable δ18O values (average 1.6‰, ± 2.1, n = 55). In some cases quartz phenocrysts have δ18O values as low as - 2.5‰. The variation in δ18O value within the quartz crystal population of individual dykes is small relative to the overall range, and core and rim material from individual quartz phenocrysts in three samples are identical within error. There is no evidence that quartz phenocryst δ18O values have been affected by fluid-rock interaction. Based on a Δquartz-magma value of 0.6‰, magma δ18O values must have been as low as - 3.1‰. Samples collected along the length of the two main QP dykes that traverse the roof pendant have quartz phenocryst δ18O values that range from + 1.1 to + 4.6‰, and - 2.3 to + 5.6‰, respectively. These δ18O values correlate negatively ( r = - 0.96) with initial 87Sr/86Sr, which can be explained by the event that lowered δ18O values of the source being older than the dykes. We suggest that the QP dykes were fed by magma produced by partial melting of gneiss, which had been variably altered at high temperature by 18O-depleted meteoric water during global glaciation at 550 Ma. The early melts had variable δ18O value but as melt pockets interconnected during melting, the δ18O values approached that of average gneiss. Variable quartz phenocryst

  11. Nuclear reactions induced by the bombardment of 18O with 18O

    International Nuclear Information System (INIS)

    Kalinsky, D.; Melnik, D.; Smilansky, U.; Trautner, N.; Horowitz, Y.; Mordechai, S.

    1977-01-01

    Angular distributions have been measured for the elastic, inelastic, one and two-neutron transfer reactions for the system 18 O + 18 O at center of mass energies ranging from 10.0 to 18.0 MeV, at c.m. angles between 90deg and 125deg. The inelastic scattering data were analyzed assuming a collective excitation mechanism and with a coupled channels approach. In order to obtain a good fit it was necessary to include a hexadecapole deformation. The one and two neutron transfer reactions were analyzed in terms of a single step finite range plus recoil DWBA theory. (author)

  12. Holocene record of precipitation seasonality from lake calcite δ18O in the central Rocky Mountains, United States

    Science.gov (United States)

    Anderson, Lesleigh

    2011-01-01

    A context for recent hydroclimatic extremes and variability is provided by a ~10 k.y. sediment carbonate oxygen isotope (??18O) record at 5-100 yr resolution from Bison Lake, 3255 m above sea level, in northwestern Colorado (United States). Winter precipitation is the primary water source for the alpine headwater lake in the Upper Colorado River Basin and lake water ??18O measurements reflect seasonal variations in precipitation ??18O. Holocene lake water ??18O variations are inferred from endogenic sedimentary calcite ??18O based on comparisons with historic watershed discharge records and tree-ring reconstructions. Drought periods (i.e., drier winters and/or a more rain-dominated seasonal precipitation balance) generally correspond with higher calcite ??18O values, and vice-versa. Early to middle Holocene ??18O values are higher, implying a rain-dominated seasonal precipitation balance. Lower, more variable ??18O values after ca. 3500 yr ago indicate a snow-dominated but more seasonally variable precipitation balance. The middle to late Holocene ??18O record corresponds with records of El Ni??o Southern Oscillation intensification that supports a teleconnection between Rocky Mountain climate and North Pacific sea-surface temperatures at decade to century time scales. ?? 2011 Geological Society of America.

  13. Pulmonary NO and C18O2 uptake during pressure-induced lung expansion in rabbits.

    Science.gov (United States)

    Heller, Hartmut; Schuster, Klaus-Dieter

    2007-01-01

    In artificially ventilated animals we investigated the dependence of the pulmonary diffusing capacities of nitric oxide (NO) and doubly 18O-labeled carbon dioxide (DLNO, DLC18O2) on lung expansion with respect to ventilator-driven increases in intrapulmonary pressure. For this purpose we applied computerized single-breath experiments to 11 anesthetized paralyzed rabbits (weight 2.8-3.8 kg) at various alveolar volumes (45-72 ml) by studying the almost entire inspiratory limb of the respective pressure/volume curves (intrapulmonary pressure: 6-27 cmH2O). The animals were ventilated with room air, employing a computerized ventilatory servo-system that we designed to maintain mechanical ventilation and to execute the particular lung function tests automatically. Each single-breath maneuver was started from residual volume (13.5+/-2 ml, mean+/-SD) by inflating the rabbit lungs with 35-55 ml indicator gas mixture containing 0.05% NO in N2 or 0.9% C18O2 in N2. Alveolar partial pressures of NO and C18O2 were measured by respiratory mass spectrometry. Values of DLNO and DLC18O2 ranged between 1.55 and 2.49 ml/(mmHg min) and 11.7 and 16.6 ml/(mmHg min), respectively. Linear regression analyses yielded a significant increase in DLNO with simultaneous increase in alveolar volume (Pvolume on DLC18O2 values.

  14. Tritium contamination in [18O] water containing 18F produced by a cyclotron

    International Nuclear Information System (INIS)

    Ito, S.; Saze, T.; Sakane, H.; Nishizawa, K.

    2003-01-01

    Tritium in the target [ 18 O] water irradiated with 9.6 MeV protons for producing [ 18 F] fluoride by 18 O(p, n) 18 F reaction was predicted from the consideration on the Q value of the 18 O(p, t) 16 O reaction. A tritium beta ray spectrum was measured by a liquid scintillation counter equipped with a multichannel analyzer. The ratio of the 3 H activity to the 18 F activity in the [ 18 O] target water was 2.4x10 -6 at the beam current of 25μA. Tritium also was detected in the [ 18 O] water for recycling and the wasted acetonitrile [ 18 O] water. The purified [ 18 F]-FDG solution was not contaminated by 3 H. The 40% 3 H out of the produced activity was lost in the course of the [ 18 F]-FDG synthesis. It was suggested that 3 H evaporated into the air during [ 18 F]-FDG synthesis and caused contamination of the workroom. The radiation workers should be prevented from environmental 3 H contamination. (author)

  15. Electroexcitation of 4+ states in 18O

    International Nuclear Information System (INIS)

    Manley, D.M.; Sellers, R.M.; Niboh, M.M.

    1993-01-01

    Measurements of electron scattering from 18 O were performed at the MIT-Bates Linear Accelerator Center at 110 degrees and 140 degrees, at momentum transfers ranging from about 1.2 to 2.5 fm -1 . Form factors were extracted for 57 discrete states with excitation energies up to about 25 MeV. The lowest 4 + states at 3.55 and 7.12 MeV are excited strongly and their form factors are well determined from prior measurements. The state at 3.65 MeV has a large (1d 5/2 )2 2p-0h component while the state at 7.12 MeV has a large 4p-2h component with the we ampersand k-coupling configuration, 20 Ne(4 + )direct-product 14 C(0 + ). New form-factor measurements will be presented for normal-parity states at 8.96 MeV and 11.67 MeV. The state at 8.96 MeV is identified as the 4 + state with a large (1d 5/2 )(ld 3/2 ) 2p-0h component, and the state at 11.67 MeV is identified as the 4 + state belonging to a K π = 2 + rotational band having large 4p-2h components and headed by a 2 + state at 9.38 MeV. New measurements for the state at 9.36 MeV will be presented as well

  16. Metrology for stable isotope reference materials: 13C/12C and 18O/16O isotope ratio value assignment of pure carbon dioxide gas samples on the Vienna PeeDee Belemnite-CO2 scale using dual-inlet mass spectrometry.

    Science.gov (United States)

    Srivastava, Abneesh; Michael Verkouteren, R

    2018-05-25

    Isotope ratio measurements have been conducted on a series of isotopically distinct pure CO 2 gas samples using the technique of dual-inlet isotope ratio mass spectrometry (DI-IRMS). The influence of instrumental parameters, data normalization schemes on the metrological traceability and uncertainty of the sample isotope composition have been characterized. Traceability to the Vienna PeeDee Belemnite(VPDB)-CO 2 scale was realized using the pure CO 2 isotope reference materials(IRMs) 8562, 8563, and 8564. The uncertainty analyses include contributions associated with the values of iRMs and the repeatability and reproducibility of our measurements. Our DI-IRMS measurement system is demonstrated to have high long-term stability, approaching a precision of 0.001 parts-per-thousand for the 45/44 and 46/44 ion signal ratios. The single- and two-point normalization bias for the iRMs were found to be within their published standard uncertainty values. The values of 13 C/ 12 C and 18 O/ 16 O isotope ratios are expressed relative to VPDB-CO 2 using the [Formula: see text] and [Formula: see text] notation, respectively, in parts-per-thousand (‰ or per mil). For the samples, value assignments between (-25 to +2) ‰ and (-33 to -1) ‰ with nominal combined standard uncertainties of (0.05, 0.3) ‰ for [Formula: see text] and [Formula: see text], respectively were obtained. These samples are used as laboratory reference to provide anchor points for value assignment of isotope ratios (with VPDB traceability) to pure CO 2 samples. Additionally, they serve as potential parent isotopic source material required for the development of gravimetric based iRMs of CO 2 in CO 2 -free dry air in high pressure gas cylinder packages at desired abundance levels and isotopic composition values. Graphical abstract CO 2 gas isotope ratio metrology.

  17. Determination of 18O concentrations in microsamples of biological fluids

    International Nuclear Information System (INIS)

    Cohen, D.D.; Bradshaw, S.D.; Bradshaw, F.J.

    1990-01-01

    The 18 O(p, α) 15 N reaction has been developed for the analysis of microsamples of biological fluids containing 18 O-enriched water. Samples as small as 50 μl have been used. Well characterized Ta 2 O 5 targets were prepared from these fluids and irradiated with several hundred nA of protons from the 3 MV Van de Graaff at Lucas Heights. The broad (47 keV) 846 kV resonance in this reaction was used to measure 18 O concentrations down to natural backgrounds (0.2 at.%) in a few minutes of accelerator running time. Concentrations of 18 O from 0 to 5 at.% were measured in body fluids in small Australian lizards directly after doping with 18 O-enriched water and then again after several days of roaming around in their natural desert environments. The changes in these levels were related to the metabolic rates of these animals. (orig.)

  18. High-18O granitic plutons from the Frontenac Axis, Grenville Province of Ontario, Canada

    International Nuclear Information System (INIS)

    Shieh, Y.-N.

    1985-01-01

    18 O/ 16 O ratios have been determined for whole rock as well as coexisting minerals from nine syn- to post-tectonic monzonite and quartz monzonite plutons in the Westport-Gananoque area covering approximately 2500 km 2 . The plutons fall into two distinct isotopic groups: (I) Low- 18 O group: Rideau Lake, Westport, and Wolfe Lake plutons and (II) High- 18 O group: Lyndhurst, Perth Road, Battersea, Gananoque, South Lake and Crow Lake plutons. The 18 O/ 16 O ratios of granitic rocks from the latter group are among the highest ever reported in the literature. The isotopic compositions of samples within each pluton bear no relationship to the sample distance from the intrusive contacts nor are they affected by the types of country rocks into which they are emplaced. Oxygen isotope fractionations among coexisting quartz, feldspar, biotite and magnetite all show normal plutonic values. Thus, all lines of evidence suggest that the monzonite and quartz monzonite plutons did not acquire their characteristic 18 O/ 16 O ratios at the present level of exposure, either by isotopic exchange with the surrounding metasedimentary country rocks or by any post-crystallization low-temperature alteration processes. The results are discussed. (author)

  19. Reef coral δ18O thermometer in Hainan island waters, south China sea

    International Nuclear Information System (INIS)

    He Xuexian; Peng Zicheng; Wang Zhaorong; Huo Weiguo; Tan Jun; Nie Baofu; Chen Tegu; Zhong Jinliang

    2000-01-01

    An 18-year-long (1981-1998) study was conducted in Hainan Island waters (22 degree 22'N, 110 degree 39'E) to determine the relationship between δ 18 O in skeletal aragonite carbonate and sea surface temperature (SST) in porites lutea of reef-building corals. δ 18 O values in skeletal aragonite carbonate were measured by means of mass spectrometry. Coral samples grew at 5 m depth at Longwan Bay. Monthly measurements of the SST from 1960 to 1998 were taken at Qinglan Bay adjacent to the place of the collected samples. The thermometer shows that SST = -4.16 δ 18 O PDB + 4.9 (r = 0.80) and dδ 18 O/dT = -0.24 per mil/degree C. The δ 18 O thermometer is strongly influenced by the rainfall and runoff. Using the thermometer, the SST in the past hundred years with monthly resolution will be reconstructed and the climatic change in the northern area of South China Sea will be hind cast

  20. Dissipative processes in 18O + 9Be and 18O + 181Ta reactions at Fermi energies

    International Nuclear Information System (INIS)

    Erdemchimeg, B.; Mikhailova, T.I.; Artyukh, A.G.; Kaminski, G.; Sereda, Yu.M.; Erdemchimeg, B.; Kaminski, G.; Sereda, Yu.M.; Colonna, M.; Di Toro, M.; Wolter, H.H.

    2010-01-01

    A study of peripheral nuclear collisions at Fermi energies with transport models is presented. It is motivated by experiments devoted to studying of isotopic yields in the reactions 18 O on 9 Be and 181 Ta at E/A = 35 MeV measured at very forward angles. The data show a two-component structure, one centered at beam velocity ('direct component') and another at lower velocities ('dissipative component'). It is shown that the transport calculations describe the general features of the dissipative component of the reaction. In our calculations we take into account the evaporation of the excited, primary projectile-like residues due to statistical decay. This improves the comparison of the results of the calculations with experiment. We find substantially different behavior of the dissipative component in the reactions with light and heavy target.

  1. δ 18O of ethanol in wine and spirits for authentication purposes.

    Science.gov (United States)

    Perini, Matteo; Camin, Federica

    2013-06-01

    Since 1986 the European Union has established official isotopic analysis methods for detecting the illegal addition of sugar and water to wine and to enable geographical traceability. In this paper we investigate the possibility of using analysis of the 18O/16O stable isotope ratio (expressed as δ 18O) of ethanol to improve detection of the watering of wine and to determine the origin of ethanol. Sixty-nine authentic wine samples from all over Italy, 59 spirits from fruit and cereals, 5 chemically synthesized ethanols, one concentrated and rectified must, one beet and one cane sugar, one fresh must, and 6 waters with increasing δ 18O values were considered. Ethanol was recovered by distillation, using a Cadiot spinning band column, following the official OIV methods. The residual water was trapped by storing the distillate for at least 24 h on a molecular sieve. The 18O/16O ratio was measured using a pyrolyser interfaced with an isotope ratio mass spectrometer. The δ (-18)O of ethanol is significantly related to the δ 18O of the fermentation water and can be considered as a reliable internal reference. The values ranged from +24‰ to +36‰ in wine (years 2008 to 2012), +10‰ to +26‰ in fruit and cereal distillates, and from -2‰ to +12‰ in synthetic ethanol. The method was shown to be effective in improving detection of the watering of wine and determining the origin of ethanol (from grapes, other fruit, or synthesis), but not in detecting the addition of cane or beet sugar to wine. © 2013 Institute of Food Technologists®

  2. Growth and {delta}{sup 13}C responses to increasing atmospheric carbon dioxide concentrations for several crop species

    Energy Technology Data Exchange (ETDEWEB)

    Hanba, Y.T.; Wada, E. [Center for Ecological Research, Kyoto University, Kyoto (Japan); Osaki, M.; Nakamura, T. [Faculty of Agriculture, Hokkaido University, Hokkaido (Japan)

    1996-04-01

    The responses of plant growth and carbon isotope discrimination ({Delta}) to elevated atmospheric CO{sub 2} concentrations for several crop species (lettuce: Lactuca sativa L.; corn: Zea Mays L. var. P3540, wheat: Triticum aestivum L. var Haruyutaka; and soybean: Glycine Max (L). Merr. var. Kitamusume) were investigated. Shoot relative growth rate was used to indicate plant growth, and {delta}{sup 13}C value of leaf materials in corn (C4 species) was used to calculate {Delta} for C3 species. Plant growth was stimulated by enriched CO{sub 2}, while {Delta} remained almost constant as CO{sub 2} concentration changed. {Delta} showed interspecific difference, and the plant species of larger {Delta} had larger relative growth rates. Relative growth rates of the plants of larger {Delta} were stimulated by CO{sub 2} enrichment more than those of the plants of smaller {Delta}. We propose that plant {Delta} could be a possible parameter to assess the interspecific difference of plant response to the increasing atmospheric CO{sub 2} concentrations. 3 figs., 2 tabs., 25 refs.

  3. {delta}{sup 13}C of Tree-Ring Lignin as an Indirect Measure of Climate Change

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, I. [CSIR Environmentek, Quaternary Dating Research Unit (South Africa)], E-mail: i.robertson@swansea.ac.uk; Loader, N. J.; McCarroll, D. [University of Wales Swansea, Department of Geography (United Kingdom); Carter, A. H. C. [University of Cambridge, Godwin Institute for Quaternary Research (United Kingdom); Cheng, L.; Leavitt, S. W. [University of Arizona, Laboratory of Tree-Ring Research (United States)

    2004-06-15

    High-resolution paleoclimatic data are an essential requirement for testing numerical models of climate change and the global carbon cycle. If the long tree-ring chronologies, originally established for the purpose of dendrochronology, are to be fully exploited as an indirect measure of past climatic variability, additional techniques are required to obtain this information. The determination of the {delta}{sup 13}C value of tree-ring cellulose has been used successfully to reconstruct past climates. However, under both aerobic and anaerobic conditions, the polysaccharide components of vascular plants (mainly cellulose and hemicelluloses) are more prone to rapid degradation than lignin. This has serious implications for the use of carbon isotope values of tree-ring cellulose as an indirect measure of past climates. An absolutely dated ring-width chronology was established for oaks (Quercus robur L.) growing at Sandringham Park in eastern England. Carbon isotope values were determined on {alpha}-cellulose and 'Klason' lignin isolated from annual latewood samples over the period AD 1895-1999. The carbon isotope values of earlywood lignin are correlated with the latewood carbon isotope values of the previous year, supporting the theory that some of the carbon utilised in earlywood synthesis is assimilated in the previous year. The high-frequency variance in the carbon isotope indices of latewood lignin and cellulose is highly correlated with combined July and August environmental variables, indicating that they were formed at similar times. There was no evidence of secondary lignification. These results demonstrate that the determination of carbon isotope values of latewood lignin offers the potential to obtain unambiguous proxy climatic data covering several millennia.

  4. The delta18O composition of Antarctic coastal current waters

    International Nuclear Information System (INIS)

    Frew, R.; Heywood, K.; Dennis, P.

    1997-01-01

    The varying proportions of 18 O to 16 O in sea water provide an oceanographic trace like salinity, but with an extra degree of freedom: salt is a tracer for the oceanic fluid, whereas the isotopic composition is a tracer specifically for the water component of that fluid. Hydrogen and oxygen isotopes are the variables most intimately related to the water component in the sea, therefore thay furnish a direct link to the water in the atmosphere and on continents and to the precipitation cycle which caused the salinity changes. The ratio of 18 O to 16 O (delta 18 O) ot waters is a powerful tracer in polar regions where sea and glacial ice processes decouple delta 18 O from salinity. Here we present observations from a significant but relatively unexplored component of the Southern Ocean current system, the Antarctic Coastal Current, and its associated Antarctic Slope Front. (author)

  5. Direct Synthesis of ESBO Derivatives-18O Labelled with Dioxirane

    Directory of Open Access Journals (Sweden)

    Stefano La Tegola

    2013-01-01

    Full Text Available This work addresses a new approach developed in our laboratory, consisting in the application of isolated dimethyldioxirane (DDO, 1a labelled with 18O for synthesis of epoxidized glyceryl linoleate (Gly-LLL, 2. We expect that this work could contribute in improving analytical methods for the determination of epoxidized soybean oil (ESBO in complex food matrices by adopting an 18O-labelled-epoxidized triacylglycerol as an internal standard.

  6. Direct Synthesis of ESBO Derivatives-18O Labelled with Dioxirane

    OpenAIRE

    La Tegola, Stefano; Annese, Cosimo; Suman, Michele; Tommasi, Immacolata; Fusco, Caterina; D'Accolti, Lucia

    2013-01-01

    This work addresses a new approach developed in our laboratory, consisting in the application of isolated dimethyldioxirane (DDO, 1a) labelled with 18O for synthesis of epoxidized glyceryl linoleate (Gly-LLL, 2). We expect that this work could contribute in improving analytical methods for the determination of epoxidized soybean oil (ESBO) in complex food matrices by adopting an 18O-labelled-epoxidized triacylglycerol as an internal standard.

  7. Relationships between δ18O in summer precipitation and temperature and moisture trajectories at Muztagata, western China

    Institute of Scientific and Technical Information of China (English)

    YU; Wusheng; YAO; Tandong; TIAN; Lide; LI; Zhen; SUN; Weizhen; WANG; Yu

    2006-01-01

    Based on summer observations of stable isotope of precipitation at Muztagata, western China, during 2002―2003, this paper presents the relationship between δ18O in precipitation and air temperature, and discusses the effect of moisture transport on δ18O in precipitation. Results show that air temperature correlates positively with δ18O in precipitation, and the temperature effect controls the δ18O of precipitation in this area. The Muztagata region exhibits high δ18O values in summer precipitation, similar to those shown at stations in adjacent regions. According to the results of our model set up to trace the moisture trajectories, the westerlies and local moisture circulation contribute to variations of oxygen isotopes in precipitation. In addition, the impacts of the moisture transport distance, the moisture transport level, and the incursion of the polar air mass also influence the variations of δ18O in precipitation. The moisture origins and transport mechanisms also contribute to the variation of δ18O in precipitation at Muztagata.

  8. Ostracod calcite records the 18O/16O ratio of the bicarbonate and carbonate ions in water

    Science.gov (United States)

    Devriendt, Laurent S.; McGregor, Helen V.; Chivas, Allan R.

    2017-10-01

    The δ18O of ostracod valves is widely used to infer water δ18O and temperature. However, ostracod δ18O appears sensitive to other environmental variables. In addition, there is species-dependent ostracod calcite 18O enrichment, relative to slowly precipitated inorganic calcite under the same conditions. Together these uncertainties complicate ostracod paleoclimate reconstructions. This study presents a new understanding of the causes of ostracod δ18O variations based on a global database of published ostracod δ18O values in lake, marine and coastal environments, and from culture experiments. The database includes associated field/experiment host water parameters including temperature (-1 to 32 °C), water δ18O (-13.2‰ to 4.3‰ VSMOW), pH (6.9-10.4), salinity (0-72 g/kg), calcite saturation states (0.6-26), and dissolved inorganic carbon concentration [DIC] (0.9-54.3 mmol/kg). The data show that: (1) the δ18O of marine and non-marine ostracods reflects the 18O/16O of the sum of host water CO32- and HCO3- ions. For example, at a given temperature, the δ18O of non-marine ostracods decreases by 4‰ to 6‰ as [CO32-]/[DIC] reaches 70%, depending on the ostracod species. In low [CO32-]/[DIC] settings (i.e. high HCO3-/CO32-), ostracod 18O/16O is close to the 18O/16O of HCO3- ions, which explains why on average ostracod δ18O is higher than the δ18O of inorganic calcite precipitated slowly under the same conditions. (2) Taxonomic offsets in ostracod δ18O vary with the host water [CO32-]/[DIC]. In environments where HCO3- ≫ CO32- (i.e. most freshwater lakes), the 18O/16O of Candonids is indistinguishable from the 18O/16O of HCO3- ions (difference of 0.10 ± 0.16‰) while the 18O/16O of Cyprids is lower than the 18O/16O of HCO3- ions by -0.77‰ to -0.32‰, Cytherids by -0.88 ± 0.29‰, and Limnocytherids by -1.12 ± 0.05‰. (3) The sensitivity of ostracod δ18O to [CO32-]/[DIC] also varies with taxonomy. For each percent increase in [CO32-]/[DIC

  9. Low-energy reaction yields for 18O(p,γ) and 18O(α,γ)

    International Nuclear Information System (INIS)

    Vogelaar, R.B.; Wang, T.R.; Kellogg, S.E.; Kavanagh, R.W.

    1990-01-01

    Resonance yields, γ-ray branching, and low-energy limits have been measured for 18 O(p,γ) and 18 O(α,γ), for E p α <0.78 MeV, using a 4π array of NaI detectors. The results confirm previous resonance strengths, and set additional constraints on possible low-energy contributions to stellar reaction rates

  10. {delta}{sup 13}C in Tibetan juniper trees - climate trends through the past 1600 years; {delta}{sup 13}C in tibetischen Wacholdern - Klimaentwicklung der letzten 1600 Jahre

    Energy Technology Data Exchange (ETDEWEB)

    Zimmermann, B.

    1998-09-01

    A {delta}{sup 13}C{sub Zell}-chronology of juniper tree cellulose from the upper treeline covering the last 1600 years was set up. The tree site is situated close to Qamdo in southeast Tibet at an altitude of 4350 m a.s.l. The southwest slope gets rain during the Indian summer monsoon. Ten trees have been sampled either by coring or by cutting of trunc-sections in pentad sampling interval. Three trees were analysed in two different radial directions. The very positive {delta}{sup 13}C{sub Zell}-data generally varying around -18,75 permille show the typical low fractionation of high mountain plants. Different interpretations are suggested for data before and after 1800 A.D. (orig.) [Deutsch] An Zellulose von Wacholdern der oberen Waldgrenze in Suedost-Tibet wurde eine 1600-jaehrige {delta}{sup 13}C{sub Zell}-Chronologie aufgestellt. Der Standort liegt in 4350 m ue.M. in der Naehe von Qamdo, ist nach Suedwest geneigt und erhaelt Niederschlaege in den Sommermonaten durch den Indischen-Suedwest-Monsun. Zehn Baeume wurden anhand von Kernen und Stammscheiben in Abschnitten von fuenf Jahren beprobt. An drei Baeumen konnten zwei Segmente desselben Baumes untersucht werden. Die im Mittel sehr positiven {delta}{sup 13}C{sub Zell}-Daten um -18,75 permille deuten auf eine fuer Hochgebirgspflanzen typische geringere Fraktionierung hin. Unterschiedliche Interpretationswege werden fuer die Daten vor und nach 1800 verfolgt. (orig.)

  11. The enigma of effective pathlength for 18O enrichment in leaf water of conifers

    Science.gov (United States)

    Roden, J. S.; Kahmen, A.; Buchmann, N. C.; Siegwolf, R. T.

    2013-12-01

    -Gordon) overestimated leaf water δ18O. A single species-specific value for L could not be determined as the fractional difference between modeled and measured leaf water δ18O did not increase with E as theory predicts. Accounting for potentially unenriched water in vascular and transfusion tissues as well as a Péclet correction that allows the value for L to change with E (as in Song et al., 2013) produced accurate predictions of leaf water δ18O. Estimates of L (for a given E) were positively correlated with mean mesophyll thickness, which to our knowledge is the first time L has been related to a leaf anatomical measure. We repeated the experiment using young needles with much higher values for E, and found a continuing trend of reduced fractional difference with E, implying that Péclet corrections may need to be modified to predict conifer needle water over the range of needle phenology and physiology. Our study will help to better quantify effective pathlength and needle water δ18O in conifers, which are some of the most important organisms used for paleoclimate reconstruction.

  12. 18O and 34S in the Upper Bartonium gypsum deposits of the Paris basin

    International Nuclear Information System (INIS)

    Fontes, J.C.; Letolle, R.

    1976-01-01

    Isotopic analyses ( 18 O and 34 S) of the Eocene gypsum from the Paris basin show a range beyond the normal Tertiary marine values. The possibility of a reduction process during diagenesis is discussed. A hypothesis of continental origin by leaching of Permotriassic deposits is proposed for this formation on the basis of a comparison of the isotopic contents recorded from Germany and eastern France

  13. Variation of the 18O/16O ratio in water samples from branches

    International Nuclear Information System (INIS)

    Foerstel, H.; Huetzen, H.

    1979-06-01

    The studies of the water turnover of plants may use the labelling of water by its natural variation of the 18 O/ 16 O ratio. The basic value of such a study is the isotope ratio in soil water, which is represented by the 18 O/ 16 O ratio in water samples from stem and branches, too. During the water transport from the soil water reservoir to the leaves of trees, no fractionation of the oxygen isotopes occurs. The oxygen isotope ratio within a single twig varies about +- 0 / 00 (variation given as standard deviation of the delta-values), within the stem of a large tree about +- 2 0 / 00 . The results of water from stems of different trees at the site of the Nuclear Research Center Juelich scatter about +- 1 0 / 00 . The delta-values from a larger area (Rur valley-Eifel hills-Mosel valley), which were collected in October 1978 during the end of the vegetation period, showed a standard deviation between +- 2.2 (Rur valley) and +- 3.6 0 / 00 (Eifel hills). The 18 O/ 16 O-delta-values of a beech wood from Juelich site are in the range of - 7.3 and - 10.1 0 / 00 (mean local precipitation 1974 - 1977: - 7.4 0 / 00 ). At the hill site near Cologne (Bergisches Land, late September 1978) we observed an oxygen isotope ratio of - 9.1 0 / 00 (groundwater at the neighbourhood between - 7.6 and 8.7 0 / 00 ). In October 1978 at an area from the Netherlands to the Mosel valley we found delta-values of branch water between - 13.9 (lower Ruhr valley) and - 13.1 (Eifel hills to Mosel valley) in comparison to groundwater samples from the same region: - 7.55 and - 8.39. There was no significant difference between delta-values from various species or locations within this area. Groundwater samples should normally represent the 18 O/ 16 O ratio of local precipitation. The low delta-values of branch water could be due to the rapid uptake of precipitation water of low 18 O content in autumn to the water transport system of plants. (orig.) [de

  14. δ18O and chemical composition of Libyan Desert Glass, country rocks, and sands: New considerations on target material

    Science.gov (United States)

    Longinelli, Antonio; Sighinolfi, Giampaolo; de Michele, Vincenzo; Selmo, Enricomaria

    2011-02-01

    Oxygen isotope and chemical measurements were carried out on 25 samples of Libyan Desert Glass (LDG), 21 samples of sandstone, and 3 of sand from the same area. The δ18O of LDG samples range from 9.0‰ to 11.9‰ (Vienna Standard Mean Ocean Water [VSMOW]); some correlations between isotope data and typological features of the LDG samples are pointed out. The initial δ18O of a bulk parent material may be slightly increased by fusion due to the loss of isotopically light pore water with no isotope exchange with oxygen containing minerals. Accordingly, the δ18O of the bulk parent material of LDG may have been about 9.0 ± 1‰ (VSMOW). The measured bulk sandstone and sand samples have δ18O values ranging from 12.6‰ to 19.5‰ and are consequently ruled out as parent materials, matching the results of previous studies. However, separated quartz fractions have δ18O values compatible with the LDG values suggesting that the modern surface sand inherited quartz from the target material. This hypothesis fits previous findings of lechatelierite and baddeleyite in these materials. As the age of the parent material reported in previous studies is Pan-African, we measured the δ18O values of bulk rock and quartz from intrusives of Pan-African age and the results obtained were compatible with the LDG values. The main element abundances (Fe, Mg, Ca, K, Na) in our LDG samples conform to previous estimates; Fe, Mg, and K tend to be higher in heterogeneous samples with dark layers. The hypothesis of a low-altitude airburst involving silica-rich surface materials deriving from weathered intrusives of Pan-African age, partially melted and blown over a huge surface by supersonic winds matches the results obtained.

  15. Using Whole Stream {delta}{sup 15}N Additions to Understand the Effects of Land Use Change on Stream Function

    Energy Technology Data Exchange (ETDEWEB)

    Deegan, L. A.; Neill, C.; Thomas, S.; Haupert, C. [Marine Biological Laboratory, Woods Hole, MA (United States); Victoria, R. L.; Krusche, A. V.; Ballester, M. V.R. [Centro de Energia Nuclear na Agricultura, Universidade de Sao Paulo, Sao Paulo (Brazil)

    2013-05-15

    In this paper we introduce an emerging new technique; the use of {delta}{sup 15}N stable isotope tracers to understand both short term and long term alterations in stream ecosystem nitrogen biogeochemistry and food web dynamics. The use of {delta}{sup 15}N isotopes to determine stream nitrogen cycling was developed in small tundra streams in Alaska (USA), but a network of researchers using similar technique has rapidly grown to answer questions about nitrogen cycling and stream food webs in a variety of ecosystem types and subject to human modifications. Here we provide an overview of some of the information that can be provided using stable isotope additions and describe the general approach of an isotope addition experiment. To illustrate the scope of isotope applicability some examples are provided of work undertaken in the Brazilian Amazon. (author)

  16. Continental-Scale Patterns in Modern Wood Cellulose δ18O: Implications for Interpreting Paleo-Wood δ18O

    Science.gov (United States)

    Richter, S. L.; Johnson, A. H.; Dranoff, M. M.; Taylor, K. D.

    2006-05-01

    Ancient wood from Siberia and Arctic Canada is readily available and spans > 40 my of changing climate. Its isotopic composition might provide useful climate information, but there are several uncertainties that must be considered when interpreting the analyzed values of this potential resource. Aside from possible problems associated with diagenetic changes, oxygen isotopes in wood cellulose (δ18Ocel) are not likely to be good paleothermometers for the distant past when global patterns of precipitation δ18O (δ18Oppt) and temperatures were different, nor might they be good predictors of δ18Oppt because paleo-relative humidity, a contributor to δ18Ocel, is difficult to quantify. We sampled naturally growing, predominantly native trees in forested regions of North American and the Caribbean to determine how applicable the established relationships among δ18Ocel, temperature, relative humidity and δ18Oppt were at the continental scale, and how much relative humidity modifies the δ18Oppt signal. Different species at the same site may or may not have access to groundwater; they may have different phenological and physiological constraints that could cause them to have different δ18Ocel. Accordingly, we assessed species composition and depth to water table as potential sources of variability in δ18Ocel. We found up to 4‰ differences among species growing at the same site with conifer cellulose more enriched than angiosperm cellulose by 1.5‰ (P<.00001). Differences in landscape position, reflecting differing access to the water table, produced small (1‰) differences in δ18Ocel. While δ18Ocel was correlated with MAT (R2=.83-.91, P<.001), average summer minimum relative humidity (RH) combined with δ18Oppt explained most of the variability (R=.96) in δ18Ocel across North American and Caribbean forests. The isotopic enrichment that occurs during the processes leading to the incorporation of precipitation oxygen in cellulose is not constant, but varies from

  17. Laser-based measurements of 18O/16O stable isotope ratios (δ18O in wine samples

    Directory of Open Access Journals (Sweden)

    Gupta M

    2013-09-01

    Full Text Available Manish Gupta,1 J Brian Leen,1 Elena Simone Franklin Berman,1 Aldo Ciambotti2 1Los Gatos Research, Mountain View, CA, USA; 2Consiglio per la Ricerca e la Sperimentazione in Agricoltura, Centro di Ricerca per l'Enologia, Asti, Italy Abstract: Wine counterfeiting is an international, multi-billion dollar issue, with some estimates suggesting that up to 5% of wines sold at auctions or secondary markets are fraudulent. Isotope ratio mass spectrometer (IRMS measurements of the 18O/16O stable isotope ratio (δ18O of water-in-wine have been used for wine authentication; however, these analyses are time-consuming and costly. In this preliminary study, off-axis integrated cavity output spectroscopy (OA-ICOS is used to quantify δ18O in wines. This laser-based method has been extensively used to study water isotopes for hydrological and medical applications. Recently, the development of a spectral contaminant identifier (SCI has extended the application of these OA-ICOS analyzers to contaminated water samples (eg, plant, soil, and leaf waters. Here, we utilize OA-ICOS with the SCI to characterize wine samples (9%–15% ethanol, and show that the laser-based instrument provides a δ18O measurement precision of ±0.07‰ (1σ and agrees with IRMS to within ±0.63‰ (1σ. Moreover, by training the SCI on isotopically-characterized wines, the agreement with IRMS improves to within ±0.30‰ (1σ. The utility of the instrument is demonstrated by measuring watered and mixed wines. The method presented here can be readily extended to address other food authentication applications. Keywords: wine isotopes, wine fraud, counterfeit wines, OA-ICOS

  18. The influence of clouds and diffuse radiation on ecosystem-atmosphere CO2 and CO18O exhanges

    Energy Technology Data Exchange (ETDEWEB)

    Still, C.J.; Riley, W.J.; Biraud, S.C.; Noone, D.C.; Buenning, N.H.; Randerson, J.T.; Torn, M.S.; Welker, J.; White, J.W.C.; Vachon, R.; Farquhar, G.D.; Berry, J.A.

    2009-05-01

    This study evaluates the potential impact of clouds on ecosystem CO{sub 2} and CO{sub 2} isotope fluxes ('isofluxes') in two contrasting ecosystems (a broadleaf deciduous forest and a C{sub 4} grassland), in a region for which cloud cover, meteorological, and isotope data are available for driving the isotope-enabled land surface model, ISOLSM. Our model results indicate a large impact of clouds on ecosystem CO{sub 2} fluxes and isofluxes. Despite lower irradiance on partly cloudy and cloudy days, predicted forest canopy photosynthesis was substantially higher than on clear, sunny days, and the highest carbon uptake was achieved on the cloudiest day. This effect was driven by a large increase in light-limited shade leaf photosynthesis following an increase in the diffuse fraction of irradiance. Photosynthetic isofluxes, by contrast, were largest on partly cloudy days, as leaf water isotopic composition was only slightly depleted and photosynthesis was enhanced, as compared to adjacent clear sky days. On the cloudiest day, the forest exhibited intermediate isofluxes: although photosynthesis was highest on this day, leaf-to-atmosphere isofluxes were reduced from a feedback of transpiration on canopy relative humidity and leaf water. Photosynthesis and isofluxes were both reduced in the C{sub 4} grass canopy with increasing cloud cover and diffuse fraction as a result of near-constant light limitation of photosynthesis. These results suggest that some of the unexplained variation in global mean {delta}{sup 18}O of CO{sub 2} may be driven by large-scale changes in clouds and aerosols and their impacts on diffuse radiation, photosynthesis, and relative humidity.

  19. Daily δ18O and δD of precipitations from 2007 to 2009 in Guangzhou, South China: Implications for changes of moisture sources

    Science.gov (United States)

    Xie, Luhua; Wei, Gangjian; Deng, Wenfeng; Zhao, Xiaoli

    2011-04-01

    SummaryOxygen and hydrogen stable isotopes ( δ18O and δD) in precipitation collected in every event from 2007 to 2009 in Guangzhou, South China, are presented in this paper. The total correlation between δ18O and δD is obtained as δD = (8.46 ± 0.13) δ18O + (15.0 ± 0.9). More negative δ18O and δD generally occur during summer and autumn, while less negative or even positive δ18O and δD occur during winter and spring. Significant negative correlations between precipitation δ18O and temperature, and between precipitation δ18O and precipitation amount are observed. Regression line changes from year to year are likely due to changes in moisture sources for the precipitation. The moisture contributed by adjacent seas or local evaporation account for the main precipitation during winter and early spring, while summer monsoon brings huge amounts of moisture from remote seas associated with higher temperature and larger precipitation amounts. Seasonal variations of the precipitation D-excess provide more details for changes in moisture sources. Higher D-excess values during winter and early spring are estimated to correspond to a lesser proportion of remote moisture, while lower D-excess values during summer and autumn correspond to larger remote moisture transported by summer monsoons. This generally agrees with the results of model analysis on single isobaric backward trajectories for air parcels during specific time periods. Results of this study imply that precipitation δ18O and δD, as well as some related paleoclimate proxies such as δ18O in speleothem and tree ring, and δD in plant-derived organic compounds and tree ring, currently cannot indicate changes in temperature or precipitation amount separately, but should be comprehensive proxies for monsoon climate.

  20. delta 18O variations in snow on the Devon Island ice cap, Northwest Territories, Canada

    International Nuclear Information System (INIS)

    Koerner, R.; Russel, R.D.

    1979-01-01

    A study of delta 18 O variations of snow samples taken on traverses across the Devon Island ice cap in June 1971, 1972, and 1973 has shown a difference between the accumulation conditions on the souteast and nortwest sides of the ice cap. On the souteast side there is an increasing depletion of 18 O in the snow with increasing elevation. This pattern is attibuted to the effect of orographic uplift of air masses moving over the ice cap from the southeast, which promotes condensation and precipitation due to adiabatic cooling. On the northwest side of the ice cap there is no evidence of any further depletion of 18 O in snow, neither with increasing distance from the possible moisture source in Baffin Bay to the southeast nor with increasing elevation if the air mass comes from the northwest. In this case condensation is due to isobaric cooling so that precipitation is generally from level cloud bases. The changes inferred for the isotopic composition of the water vapour as it rises up the southeast slope are found to be consistent with its depletion through precipitation under near-equilibrium conditions. It is calculated that approximately 30% of the moisture at sea level on the southeast side of the ice cap and 8% at the top of the ice cap are of local origin. Lower temporal and aerial variability of the delta values on the southeast side of the ice cap is attributed to dominance of the Baffin Bay low on that side Effecting consistency of storm conditions there. The delta values of ice in the ablation zone on the Sverdrup Glacier show the combined effect of ice movement from the accumulation to the ablation zone and climatic change during the period of movement from cold to warm and back to cold conditions again. (auth)

  1. Assessing methane oxidation under landfill covers and its contribution to the above atmospheric CO2 levels: The added value of the isotope (δ13C and δ18O CO2; δ13C and δD CH4) approach

    International Nuclear Information System (INIS)

    Widory, D.; Proust, E.; Bellenfant, G.; Bour, O.

    2012-01-01

    Highlights: ► Comparison of the isotope and mass balance approaches to evaluate the level of methane oxidation within a landfill. ► The level of methane oxidation is not homogenous under the landfill cover and is strongly correlated to the methane flux. ► Isotope tracking of the contribution of the methane oxidation to the CO 2 concentrations in the ambient air. - Abstract: We are presenting here a multi-isotope approach (δ 13 C and δ 18 O of CO 2 ; δ 13 C and δD of CH 4 ) to assess (i) the level(s) of methane oxidation during waste biodegradation and its migration through a landfill cover in Sonzay (France), and (ii) its contribution to the atmospheric CO 2 levels above the surface. The isotope approach is compared to the more conventional mass balance approach. Results from the two techniques are comparable and show that the CH 4 oxidation under the landfill cover is heterogenous, with low oxidation percentages in samples showing high biogas fluxes, which was expected in clay covers presenting fissures, through which CH 4 is rapidly transported. At shallow depth, more immobile biogas pockets show a higher level of CH 4 oxidation by the methanotrophic bacteria. δ 13 C of CO 2 samples taken at different heights (from below the cover up to 8 m above the ground level) were also used to identify and assess the relative contributions of its main sources both under the landfill cover and in the surrounding atmosphere.

  2. Co-occurring species differ in tree-ring δ18O trends.

    Science.gov (United States)

    John D. Marshall; Robert A. Monserud

    2006-01-01

    The stable oxygen isotope ratio (δ18O) of tree-ring cellulose is jointly determined by the δ18O of xylem water, the δ18O of atmospheric water vapor, the humidity of the atmosphere and perhaps by species-specific differences in leaf structure and function. Atmospheric...

  3. Espiritu Santo, Vanuatu Stable Isotope (delta 18O, delta 13C) Data for 1806 to 1979

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Site: Espiritu Santo Island, Vanuatu, 15S, 167E. 173 year record of d18O and d13C. Variable names: QSR Age, QSR 13C, QSR 18O, GRL Age, GRL Qtrly 13C, GRL Qtrly 18O,...

  4. Initial isotopic geochemistry ({delta} 18 O, {delta} D) of fluids from wells of the Los Humeros, Pue., geothermal field; Geoquimica isotopica ({delta} 18 O, {delta} D) inicial de fluidos de pozos del campo geotermico de Los Humeros, Pue.

    Energy Technology Data Exchange (ETDEWEB)

    Barragan Reyes, Rosa Maria; Arellano Gomez, Victor Manuel [Instituto de Investigaciones Electricas, Gerencia de Geotermia, Cuernavaca, Morelos (Mexico)]. E-mail: rmb@iie.org.mx; Ramirez Montes, Miguel; Tovar Aguado, Rigoberto [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Morelia, Michoacan (Mexico)

    2010-01-15

    Isotopic data ({delta} 18 O, {delta} D) from fluids from production wells at the Los Humeros, Pue., geothermal field were analyzed to investigate the possible origin of these fluids and the dominant processes of the reservoir at its initial state. According to pre-exploitation data, it is suggested the Los Humeros reservoir fluids are made of a mixture of meteoric water of very light isotopic composition (paleo-fluids) and andesitic water. The relationship {delta} D vs {delta} 18 O from pre-exploitation data indicates the produced fluids are composed of a mixture of (at least) two fluids with distinct isotopic compositions. At the more enriched end of the mixing relationship are the isotopic compositions of the wells H-23 and H-18 (located in the southern area of the field), while the lighter fluids were found in well H-16 (originally) and then in well H-16 (repaired). It was found that the liquid phases of deep wells are more enriched in {delta} 18 O while the shallow wells present lower values, suggesting a convection process at the initial state. Based on this isotopic profile, it is considered that even the production depths of the wells H-1, H-12 and H-16 (repaired) are just about the same, but their respective isotopic compositions are quite different. The {delta} 18 O value for well H-16 (repaired) seems to be that of condensate steam, while the corresponding values for wells H-1 and H-12 fall within the value interval of the deep wells (H-23). This suggests wells H-1 and H-12 are collecting very deep fluids enriched in {delta} 18 O. These results could be useful in creating a conceptual model of the reservoir. [Spanish] Se analizaron datos isotopicos ({delta}18 O, {delta}D) de los fluidos de pozos productores del campo geotermico de Los Humeros, Pue., para investigar el posible origen de los fluidos asi como los procesos dominantes del yacimiento en su estado inicial. De acuerdo con datos previos a la explotacion, se plantea que los fluidos del yacimiento

  5. Controls of precipitation δ18O on the northwestern Tibetan Plateau: A case study at Ngari station

    Science.gov (United States)

    Guo, Xiaoyu; Tian, Lide; Wen, Rong; Yu, Wusheng; Qu, Dongmei

    2017-06-01

    The shifting atmospheric circulation between the Indian monsoon and the westerlies on the northwestern Tibetan Plateau (TP) influences precipitation as well as precipitation isotopes. Isotopic records will therefore show historical fluctuations. To understand better the factors controlling present day precipitation δ18O values on the northwestern TP, we made continuous observations of precipitation isotopes at Ngari station from 2010 to 2013. The drivers of precipitation δ18O were investigated using analyses of their statistical relations with temperature, precipitation amount, relative humidity, and convective activities based on outgoing longwave radiation (OLR) data from NOAA satellites, and downward shortwave radiation (DSR) data collected at the Ngari automatic weather station. Atmospheric circulation patterns from NCAR reanalysis, and moisture transport paths of individual events derived from the HYSPLIT model using NCEP data, were also used to trace moisture sources. The results of our study include: (1) The slope and intercept of the Local Meteoric Water Line (LMWL) at Ngari (δD = 8.51 δ18O + 11.57 (R2 = 0.97, p < 0.01)) were higher than for the Global Meteoric Water Line (GMWL), indicating drier local climatic conditions; (2) Precipitation δ18O values showed a weak ;temperature effect; and a weak ;precipitation amount effect; at Ngari; and (3) Convection (or temperature patterns) integrated over several days (0-20) preceding each event were determined to be the main driver of precipitation isotopic values in monsoon (or non-monsoon) season. The longer (shorter) periods of τm days when correlation coefficients between precipitation δ18O and OLR were at their maxima (minima) indicate deep convective activities (shorter moisture transportation pathways) in August (June, July, and September).

  6. Effects of elevated ozone on leaf {delta}{sup 13}C and leaf conductance of plant species grown in semi-natural grassland with or without irrigation

    Energy Technology Data Exchange (ETDEWEB)

    Jaeggi, M. [Agroscope FAL Reckenholz, Swiss Federal Research Station for Agroecology and Agriculture, Air Pollution/Climate Group, CH-8046 Zurich (Switzerland)]. E-mail: maya.jaeggi@psi.ch; Saurer, M. [Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Volk, M. [Agroscope FAL Reckenholz, Swiss Federal Research Station for Agroecology and Agriculture, Air Pollution/Climate Group, CH-8046 Zurich (Switzerland); Fuhrer, J. [Agroscope FAL Reckenholz, Swiss Federal Research Station for Agroecology and Agriculture, Air Pollution/Climate Group, CH-8046 Zurich (Switzerland)

    2005-03-01

    Stable carbon isotope ratios ({delta}{sup 13}C) and leaf conductance (g{sub s}) were measured (2002, 2003) in Holcus lanatus L., Plantago lanceolata L. Ranunculus friesianus (Jord.), and Trifolium pratense L. at two levels of ozone (O{sub 3}) with or without irrigation. In non-irrigated control plots, R. friesianus showed the least negative {delta}{sup 13}C, and the smallest response to the treatments. Irrigation caused more negative {delta}{sup 13}C, especially in H. lanatus. Irrespective of irrigation, O{sub 3} increased {delta}{sup 13}C in relationship to a decrease in g{sub s} in P. lanceolata and T. pratense. The strongest effect of O{sub 3} on {delta}{sup 13}C occurred in the absence of irrigation, suggesting that under field conditions lack of moisture in the top soil does not always lead to protection from O{sub 3} uptake. It is concluded that in species such as T. pratense plants can maintain stomatal O{sub 3} uptake during dry periods when roots can reach deeper soil layers where water is not limiting. - Under natural field conditions, lack of precipitation may not protect semi-natural vegetation from O{sub 3} effects on leaf gas exchange.

  7. 2H and 18O Freshwater Isoscapes of Scotland

    Science.gov (United States)

    Meier-Augenstein, Wolfram; Hoogewerff, Jurian; Kemp, Helen; Frew, Danny

    2013-04-01

    Scotland's freshwater lochs and reservoirs provide a vital resource for sustaining biodiversity, agriculture, food production as well as for human consumption. Regular monitoring of freshwaters by the Scottish Environment Protection Agency (SEPA) fulfils legislative requirements with regards to water quality but new scientific methods involving stable isotope analysis present an opportunity combining these mandatory monitoring schemes with fundamental research to inform and deliver on current and nascent government policies [1] through gaining a greater understanding of Scottish waters and their importance in the context of climate change, environmental sustainability and food security. For example, 2H and 18O isoscapes of Scottish freshwater could be used to underpin research and its applications in: • Climate change - Using longitudinal changes in the characteristic isotope composition of freshwater lochs and reservoirs as proxy, isoscapes will provide a means to assess if and how changes in temperature and weather patterns might impact on precipitation patterns and amount. • Scottish branding - Location specific stable isotope signatures of Scottish freshwater have the potential to be used as a tool for provenancing and thus protecting premium Scottish produce such as Scottish beef, Scottish soft fruit and Scottish Whisky. During 2011 and 2012, with the support of SEPA more than 110 samples from freshwater lochs and reservoirs were collected from 127 different locations across Scotland including the Highlands and Islands. Here we present the results of this sampling and analysis exercise isotope analyses in form of 2H and 18O isoscapes with an unprecedented grid resolution of 26.5 × 26.5 km (or 16.4 × 16.4 miles). [1] Adaptation Framework - Adapting Our Ways: Managing Scotland's Climate Risk (2009): Scotland's Biodiversity: It's in Your Hands - A strategy for the conservation and enhancement of biodiversity in Scotland (2005); Recipe For Success - Scotland

  8. Runoff modeling of the Amazon basin using 18 O as a conservative tracer

    International Nuclear Information System (INIS)

    Mortatti, Jefferson; Victoria, Reynaldo L.; Moraes, Jorge M.; Rodrigues Junior, Jose C.; Matsumoto, Otavio M.

    1997-01-01

    Using the δO 18 O content of natural waters as a conservative tracer, a runoff modelling of the Amazon river basin was carried out in order to study the hydrological characteristics of the precipitation-runoff relationship. Measurements of the δ 18 O in rainfall waters made in the high Solimoes region at Benjamin Constant, in the central part of basin at Manaus, and at the mouth near the Marajo Island, while the river waters were measured at Obidos only, as a proxy for the mouth, during the 1973-1974 hydrological years. The hydrography separation of the Amazon river was performed using the isotopic method to estimate the contributions of the surface runoff (event water) and baseflow (pre-event water) components to the total river flow. At peak discharge, the average contribution of the baseflow was 57% of the total river flow. The annual average contributions for surface runoff and baseflow were 30.3 and 69.7%, respectively. The residence time of the subsurface water in the basin was estimated as being 7 months, by fitting a sinusoidal function to the isotopic values of rainfall and river waters. The low values of the amplitude damping in the basin suggest high mixing waters during the runoff process. (author). 21 refs., 4 figs., 1 tab

  9. The synthesis of 8-β-[(methylsulfinyl-[18O])-methyl]-6-propylergoline

    International Nuclear Information System (INIS)

    Wheeler, W.J.

    1987-01-01

    The synthesis of 18 O-labeled 8-Β-[(methylsulfinyl)-methyl]-6-propyl-ergoline(pergolide-[ 18 O]-sulfoxide) of undetermined stereochemistry by the reaction of 8-Β-(methylthiomethyl)-6-propyl-ergoline (pergolide) with bis-(4-methoxyphenyl)-selen-[ 18 O]-oxide in acetic acid is described. Although the yields were low and the incorporation of 18 O was not high, this procedure represents a convenient method for the preparation of 18 O-labeled sulfoxides of pergolide and other sulfides present in compounds for which the usual methods are inappropriate. (author)

  10. Improved online δ18O measurements of nitrogen- and sulfur-bearing organic materials and a proposed analytical protocol

    Science.gov (United States)

    Qi, H.; Coplen, T.B.; Wassenaar, L.I.

    2011-01-01

    It is well known that N2 in the ion source of a mass spectrometer interferes with the CO background during the δ18O measurement of carbon monoxide. A similar problem arises with the high-temperature conversion (HTC) analysis of nitrogenous O-bearing samples (e.g. nitrates and keratins) to CO for δ18O measurement, where the sample introduces a significant N2 peak before the CO peak, making determination of accurate oxygen isotope ratios difficult. Although using a gas chromatography (GC) column longer than that commonly provided by manufacturers (0.6 m) can improve the efficiency of separation of CO and N2 and using a valve to divert nitrogen and prevent it from entering the ion source of a mass spectrometer improved measurement results, biased δ18O values could still be obtained. A careful evaluation of the performance of the GC separation column was carried out. With optimal GC columns, the δ18O reproducibility of human hair keratins and other keratin materials was better than ±0.15 ‰ (n = 5; for the internal analytical reproducibility), and better than ±0.10 ‰ (n = 4; for the external analytical reproducibility).

  11. Relation between D/H ratios and 18O /16O ratios in cellulose from linen and maize - Implications for paleoclimatology and for sindonology

    Science.gov (United States)

    DeNiro, Michael J.; Sternberg, Leonel D.; Marino, Bruno D.; Druzik, James R.

    1988-09-01

    The 18O /16O ratios of cellulose and the D/H ratios of cellulose nitrate were determined for linen, a textile produced from the fibers of the flax plant Linum usitatissimum, and for maize ( Zea mays) from a variety of geographic locations in Europe, the Middle East, and North and South America. The regression lines of δD values on δ 18O values had slopes of 5.4 and 5.8 for the two species. Statistical analysis of results reported in the only other study in which samples of a single species (the silver fir Abies pindrow) that grew under a variety of climatic conditions were analyzed yielded slopes of ~6 when δD values of cellulose nitrate were regressed on δ 18O values of cellulose. The occurrence of this previously unrecognized relationship in three species suggests it may obtain in other plants as well. Determining the basis for this relationship, which is not possible given current understanding of fractionation of the isotopes of oxygen and hydrogen by plants, should lead to increased understanding of how D/H and 18O /16O ratios in cellulose isolated from fossil plants are related to paleoclimates. The separation of most linen samples from Europe from those originating in the Middle East when δD values are plotted against δ 18O values suggests it may be possible to use the isotope ratios of cellulose prepared from the Shroud of Turin to resolve the controversy concerning its geographic origin.

  12. 18O, 2H and 3H isotopic composition of precipitation and shallow groundwater in Olkiluoto

    International Nuclear Information System (INIS)

    Hendriksson, N.; Karhu, J.; Niinikoski, P.

    2014-12-01

    The isotopic composition of oxygen and hydrogen in local precipitation is a key parameter in the modelling of local water circulation. This study was initiated in order to provide systematic monthly records of the isotope content of atmospheric precipitation in the Olkiluoto area and to establish the relation between local rainfall and newly formed groundwater. During January 2005 - December 2012, a total of 85 cumulative monthly rainfall samples and 68 shallow groundwater samples were collected and the isotopic composition of oxygen and hydrogen was recorded for all those samples. Tritium values are available for 79 precipitation and 65 groundwater samples. Based on the 8-year monitoring, the long-term weighted annual mean isotope values of precipitation and the mean values of shallow groundwater are -11.59 per mille and -11.27 per mille for δ 18 O, - 82.3 per mille and -80.3 per mille for δ 2 H and 9.8 and 9.1 TU for tritium, respectively. Based on these data, the mean stable isotope ratios of groundwater represent the long-term mean annual isotopic composition of local precipitation. The precipitation data were used to establish the local meteoric water line (LMWL) for the Olkiluoto area. The line is formulated as: δ 2 H = 7.45 star δ 18 O + 3.82. The isotope time series reveal a change in time. The increasing trend for the δ 18 O and δ 2 H values may be related to climatic variability while the gradual decline observed in the 3 H data is attributed to the still continuing decrease in atmospheric 3 H activity in the northern hemisphere. The systematic seasonal and long-term tritium trends suggest that any potential ground-level tritium release from the Olkiluoto nuclear power plants is insignificant. The d-excess values of Olkiluoto precipitation during the summer period indicated that a notable amount of re-cycled Baltic Sea water may have contributed to precipitation in the Finnish southern coast. Preliminary estimates of the evaporated Baltic Sea water

  13. INVESTIGATION OF STABLE ISOTOPE OF 18O AND 2H IN SHALLOW GROUNDWATER FROM KARAWANG AREA

    Directory of Open Access Journals (Sweden)

    E. Ristin Pujiindiyati

    2010-06-01

    Full Text Available Karawang area is well known as an agriculture area and 2% area is utilized for industries. Clean water demands increase due to developing industry development and population increasement. The origin of groundwater is necessary to keep the sustainability of water resources in this area. Stable isotopes such as 18O and 2H can be used as a parameter to trace the ground water origin. The methods used were Epstein-Mayeda and Zinc reduction for analysis 18O and 2H, respectively. Sampling period was conducted in major dry season in year 2002. The result showed that evaporation effect had influenced to the content of both isotopes in its shallow groundwater that caused a slope shift from its local meteoric line. The origin of its shallow groundwater was from rainwater infiltrating directly in less than 10 m altitude. Citarum River showed more depleted values in both isotopes compared to shallow groundwater and it indicated that its water might originate from spring at the altitude of 600 m.     Keywords: oxygene-18, deuterium, groundwater, isotope

  14. Two-neutron stripping in ({sup 18}O, {sup 16}O) and (t,p) reactions

    Energy Technology Data Exchange (ETDEWEB)

    Cavallaro, M.; Agodi, A.; Carbone, D.; Cunsolo, A. [INFN - Laboratori Nazionali del Sud, Via S. Sofia 62, I-95125 Catania (Italy); Bondì, M.; Cappuzzello, F.; Nicolosi, D.; Tropea, S. [INFN - Laboratori Nazionali del Sud, Via S. Sofia 62, I-95125 Catania, Italy and Dipartimento di Fisica e Astronomia, Università di Catania, Via S. Sofia 64, I-95125 Catania (Italy); Borello-Lewin, T.; Rodrigues, M. R. D. [Instituto de Física - Universidade de São Paulo, Rua do Matão Travessa R Nr.187 CEP 05508-090 Cidade Universitária, São Paulo (Brazil); De Napoli, M. [INFN - Sezione di Catania, Via S. Sofia 64, I-95125 Catania (Italy); Garcia, V. N. [Instituto de Física, Universidade Federal Fluminense, Avenida Litoranea s/n, Gragoata, 24210-340, Niteroi, RJ (Brazil); Linares, R.; Lubian, J.; Paes, B. [Instituto de Física, Universidade Federal Fluminense, Avenida Litoranea s/n, Gragoata , 24210-340, Niteroi, RJ (Brazil); Foti, A. [Dipartimento di Fisica e Astronomia, Università di Catania, Via S. Sofia 64, I-95125 Catania, Italy and INFN - Sezione di Catania, Via S. Sofia 64, I-95125 Catania (Italy)

    2014-11-11

    The {sup 12}C({sup 18}O,{sup 16}O){sup 14}C reactions has been investigated at 84 MeV incident energy. The charged ejectiles produced in the reaction have been momentum analyzed and identified by the MAGNEX magnetic spectrometer. Q-value spectra have been extracted with an energy resolution of 160 keV (Full Width at Half Maximum) and several known bound and resonant states of {sup 14}C have been identified up to 15 MeV. In particular, excited states with dominant 2p - 4h configuration are the most populated. The absolute values of the cross sections have been extracted showing a striking similarity with those measured for the same transitions by (t,p) reactions. This indicates that the effect of the {sup 16}O core is negligible in the reaction mechanism.

  15. The quadrupole moment of the first excited state of 18O

    International Nuclear Information System (INIS)

    Fewel, M.P.; Baxter, A.M.; Kean, D.C.; Spear, R.H.

    1976-11-01

    Using the re-orientation effect in Coulomb excitation, the quadrupole moment, Qsub(2 + ), of the first excited state of 18 O is found to be -0.100 +- 0.030 eb. The analysis assumes, on the basis of previous measurements, that B(E2; 0 + → 2 + ) = 0.0044 +- 0.0004 e 2 b 2 . A correction (+0.032 eb) for the effect of the giant dipole resonance, based on the hydrodynamic model, has been applied. Evidence is presented that some other determinations of Qsub(2 + ) were performed at too high a bombarding energy. The present value of Qsub(2 + ) is smaller in magnitude than that reported by Kleinfeld et al. (1975), but remains larger than the value of -0.034 eb predicted by a recent shell-model calculation. (Author)

  16. Investigation of the alpha cluster states in 22Ne through the transfer induced breakup reaction 12C (18O, 18O + α)8Be at E(18O) 94.5 MeV

    International Nuclear Information System (INIS)

    Adhikari, S.; Basu, C.; Mitra, A.K.; Behera, B.R.; Ray, S.; Kumar, Suresh; Chatterjee, A.

    2008-01-01

    The nucleus 22 Ne like 18 O and 20 Ne has been sparsely investigated experimentally for an 18 O + α cluster structure. Only one experiment has reported the 22 Ne alpha cluster states using the same reaction but a much higher energy. One other experiment also reported the states with a different target and the results of these experiments are different. Therefore the 22 Ne structure has been analyzed in this work

  17. A new derivatization method for δ18O analysis of individual carbohydrates with GC-Pyrolysis-IRMS

    Science.gov (United States)

    Lehmann, M. M.; Siegwolf, R. T.; Saurer, M.; Blees, J.; Fischer, M.; Zech, M.

    2015-12-01

    Compound specific isotope analysis (CSIA) with gas chromatography coupled to an isotope ratio mass spectrometer (GC-Pyr-IRMS) is nowadays a powerful tool that is widely used by a broad spectrum of research fields to investigate the isotopic signature of diverse metabolites. While many CSIA methods for carbon, hydrogen, and nitrogen isotopes are known, CSIA methods for the analysis of oxygen isotopes (δ18O) are still not widely established. Especially, reliable and precise methods for the δ18O analyses of individual carbohydrates are scarce, which is caused by the highly sensitive nature of the sugars. However, carbohydrates are important components of living organisms, source for many biochemical reactions, and can be found in all organisms, in soils, sediments, and in air. Thus, a method, allowing the investigation of the 18O/16O ratio in carbohydrates will enhance the scope of research using isotopes. We developed a new and easy to handle derivatization method to determine δ18O in carbohydrates with GC-Pyr-IRMS that consists of a catalyzed one-pot reaction in acetonitrile, resulting in complete methylation of all sugar hydroxyl groups within 24 hours, with silver oxide as the proton acceptor and methyl iodide as the methyl group carrier. Results derived from standard material show unrivalled δ18O precision ranging from about 0.2 to 1.1 ‰ for different individual carbohydrates of different classes and a generally very good accuracy, with a narrow range of 0.2 ‰ around the reference value, despite of high area variations. We applied this method on real samples, demonstrating that the method can commonly be used for analyzing honey samples, and for the analyses of more complex carbohydrate mixtures from plant leaves, including glucose, fructose, pinitol, and sucrose. Our new method may be used for food, beverage, and medical applications, as well as for biogeochemical and paleoclimatic sciences.

  18. Stable isotope time-series in mammalian teeth: In situ δ18O from the innermost enamel layer

    Science.gov (United States)

    Blumenthal, Scott A.; Cerling, Thure E.; Chritz, Kendra L.; Bromage, Timothy G.; Kozdon, Reinhard; Valley, John W.

    2014-01-01

    Stable carbon and oxygen isotope ratios in mammalian tooth enamel are commonly used to understand the diets and environments of modern and fossil animals. Isotope variation during the period of enamel formation can be recovered by intra-tooth microsampling along the direction of growth. However, conventional sampling of the enamel surface provides highly time-averaged records in part due to amelogenesis. We use backscattered electron imaging in the scanning electron microscope (BSE-SEM) to evaluate enamel mineralization in developing teeth from one rodent and two ungulates. Gray levels from BSE-SEM images suggest that the innermost enamel layer, <20 μm from the enamel-dentine junction, is highly mineralized early in enamel maturation and therefore may record a less attenuated isotopic signal than other layers. We sampled the right maxillary incisor from a woodrat subjected to an experimentally induced water-switch during the period of tooth development, and demonstrate that secondary ion mass spectrometry (SIMS) can be used to obtain δ18O values with 4-5-μm spots from mammalian tooth enamel. We also demonstrate that SIMS can be used to discretely sample the innermost enamel layer, which is too narrow for conventional microdrilling or laser ablation. An abrupt δ18O switch of 16.0‰ was captured in breath CO2, a proxy for body water, while a laser ablation enamel surface intra-tooth profile of the left incisor captured a δ18O range of 12.1‰. The innermost enamel profile captured a δ18O range of 15.7‰, which approaches the full magnitude of δ18O variation in the input signal. This approach will likely be most beneficial in taxa such as large mammalian herbivores, whose teeth are characterized by less rapid mineralization and therefore greater attenuation of the enamel isotope signal.

  19. Coupled channel effects in quasi-elastic barrier distributions of 16,18O + 206Pb systems

    International Nuclear Information System (INIS)

    Jha, V.; Roy, B.J.; Parkar, V.V.; Kumawat, H.; Pal, U.K.; Pandit, S.K.; Mahata, K.; Shrivastava, A.; Mohanty, A.K.

    2013-01-01

    The fusion barrier distribution and QEBD for the 16 O + 208 Pb have been studied in great detail. The couplings due to the collective excitations of the colliding nuclei are found to have the dominant effect as deduced by the conventional coupled-channels calculations used to explain the experimental QEBD and fusion barrier distributions. In contrast, for the 18 O + 206 Pb system, the role of single neutron stripping (Q-value= -1.308 MeV) and neutron pair transfer (Q-value = + 1.917 MeV) are expected to be significant. In the present work, the QEBD measurements for the 18 O + 206 Pb system are performed for the investigation of these aspects

  20. Observation of Isotope Ratios (δ2H, δ18O, 87Sr/86Sr) of Tap Water in Urban Environments

    Science.gov (United States)

    Mancuso, C. J.; Tipple, B. J.; Ehleringer, J. R.

    2014-12-01

    Urban environments are centers for rapidly growing populations. In order to meet the culinary water needs of these areas, municipal water departments use water from multiple locations and/or sources, often piped differentially to different locations within a municipality. This practice creates isotopically distinct locations within an urban area and therefore provides insight to urban water management practices. In our study we selected urban locations in the Salt Lake Valley, UT (SLV) and San Francisco Bay Area, CA (SFB) where we hypothesized geographically distinct water isotopic ratio differences existed. Within the SLV, municipal waters come from the same mountainous region, but are derived from different geologically distinct watersheds. In contrast, SFB waters are derived from regionally distinct water sources. We hypothesized that the isotope ratios of tap waters would differ based upon known municipal sources. To test this, tap water samples were collected throughout the urban regions in SLV and SFB and analyzed for δ2H, δ18O and 87Sr/86Sr isotope ratios. Seasonal collections were also made to assess if isotope ratios differed throughout the year. Within SLV and SFB, different regions were characterized by distinct paired δ18O and 87Sr/86Sr values. These different realms also agreed with known differences in municipal water supplies within the general geographic region. Waters from different cities within Marin County showed isotopic differences, consistent with water derived from different local reservoirs. Seasonal variation was observed in paired δ18O and 87Sr/86Sr values of tap water for some locations within SLV and SFB, indicating management decisions to shift from one water source to another depending on demand and available resources. Our study revealed that the δ18O and 87Sr/86Sr values of tap waters in an urban region can exhibit significant differences despite close spatial proximity if districts differ in their use of local versus

  1. A low-δ18O intrusive breccia from Koegel Fontein, South Africa: Remobilisation of basement that was hydrothermally altered during global glaciation?

    Science.gov (United States)

    Olianti, Camille A. E.; Harris, Chris

    2018-02-01

    The Cretaceous Koegel Fontein igneous complex is situated on the west coast of South Africa, and has a high proportion of rocks with abnormally low δ18O values. The rocks with the lowest δ18O values (- 5.2‰) belong to intrusive matrix-supported breccia pipes and dykes, containing a variety of clast types. The breccia rocks range in SiO2 from 44 to 68 wt% and their whole-rock δ18O values vary between - 5.2‰ and + 1.8‰. The major and trace element composition of the breccia rocks is consistent with them containing variable proportions of clasts of Cretaceous intrusive rocks and basement gneiss and the matrix being fluidized material derived from the same source as the clasts. Based on the nature of the clasts contained in the breccia, it was emplaced just prior to intrusion of the main Rietpoort Granite at 134 Ma. All components of the breccia have low δ18O value and, at least in the case of the gneiss clasts, this predates incorporation in the fluidized material. Although the early Cretaceous appears to have been a period of cold climate, it is unlikely that the δ18O values of ambient precipitation ( - 10‰) would have been low enough to have generated the required 18O-depletion. The basement gneiss was probably 2-3 km below the Cretaceous surface, minimizing the possibility of interaction with isotopically unmodified meteoric water, and there is no evidence for foundered blocks of cover rocks in the breccia. There is, therefore, no evidence for downwards movement of material. We favour a model where basement gneiss interacted with extremely 18O-depleted fluid during crustal reworking at 547 Ma, a time of global glaciation. Low-δ18O metamorphic fluids produced by dehydration melting of 18O-depleted gneiss became trapped and, as the fluid pressure increased, failure of the seal resulted in explosive upwards movement of fluidized breccia. Migration was along pre-existing dykes, incorporating fragments of these dykes, as well as the country rock gneiss.

  2. Tooth Enamel δ13C and δ18O Variations in Modern and Archaeological Horses From Northern Kazakhstan as Indicators of Regional Climate

    Science.gov (United States)

    Sikora, M. T.; Rosenmeier, M. F.; Stacy, E. M.; Olsen, S. L.

    2007-12-01

    In this study, the oxygen and carbon isotope values of tooth enamel were measured in forty-one modern and twenty-three Copper Age (3600 - 3100 B.C.) horse specimens from the grassland steppe region of northern Kazakhstan. Modern tooth enamel δ13C and δ18O values were compared with the carbon isotopic compositions of local vegetation and the δ18O values of meteoric waters. Tooth enamel isotope values within the Copper Age specimens (attributed to the so-called Botai culture) were, in turn, compared with modern samples. Average carbon isotopic values within modern bulk tooth enamel samples ranged between -13.7 and -12.0‰ (VPDB). This suggests that the diet of modern northern Kazakhstani horses is comprised almost entirely of C3 plants (considering enamel-diet fractionation factors) consistent with documented grassland compositions within the region. The observed amplitude of δ13C variations within individual teeth (typically less than ~2‰) suggests only minimal seasonal variation in the δ13C of grasses attributed to heat and water stress. Alternatively, the minimal seasonal changes observed within intra-tooth δ13C values may be the direct result of fodder provisioning. Ingested water δ18O values derived from oxygen isotope ratios within bulk tooth enamel samples appear statistically indistinguishable from estimates of regional precipitation, suggesting that Kazakhstani horse tooth enamel δ18O measurements may be used as a direct estimate of the oxygen isotopic composition of meteoric waters. Intra-tooth oxygen isotopic variations therefore reflect the pronounced seasonal variability in precipitation δ18O values tied to temperature changes and amount effects observed annually within Kazakhstan. However, these intra-tooth isotopic variations exhibit slightly reduced amplitudes relative to meteoric water values, suggesting that horses likely consume water from buffered sources such as lakes and wells. Average bulk tooth enamel δ13C values within

  3. The δ2H and δ18O of tap water from 349 sites in the United States and selected territories

    Science.gov (United States)

    Coplen, Tyler B.; Landwehr, Jurate M.; Qi, Haiping; Lorenz, Jennifer M.

    2013-01-01

    Because the stable isotopic compositions of hydrogen (δ2H) and oxygen (δ18O) of animal (including human) tissues, such as hair, nail, and urine, reflect the δ2H and δ18O of water and food ingested by an animal or a human and because the δ2H and δ18O of environmental waters vary geographically, δ2H and δ18O values of tap water samples collected in 2007-2008 from 349 sites in the United States and three selected U.S. territories have been measured in support of forensic science applications, creating one of the largest databases of tap water δ2H and δ18O values to date. The results of replicate isotopic measurements for these tap water samples confirm that the expanded uncertainties (U = 2μc) obtained over a period of years by the Reston Stable Isotope Laboratory from δ2H and δ18O dual-inlet mass spectrometric measurements are conservative, at ±2‰ and ±0.2 ‰, respectively. These uncertainties are important because U.S. Geological Survey data may be needed for forensic science applications, including providing evidence in court cases. Half way through the investigation, an isotope-laser spectrometer was acquired, enabling comparison of dual-inlet isotope-ratio mass spectrometric results with isotope-laser spectrometric results. The uncertainty of the laser-based δ2H measurement results for these tap water samples is comparable to the uncertainty of the mass spectrometric method, with the laser-based method having a slightly lower uncertainty. However, the δ18O uncertainty of the laser-based method is more than a factor of ten higher than that of the dual-inlet isotoperatio mass spectrometric method.

  4. A novel methylation derivatization method for δ(18)O analysis of individual carbohydrates by gas chromatography/pyrolysis-isotope ratio mass spectrometry.

    Science.gov (United States)

    Lehmann, Marco M; Fischer, Maria; Blees, Jan; Zech, Michael; Siegwolf, Rolf T W; Saurer, Matthias

    2016-01-15

    The oxygen isotope ratio (δ(18)O) of carbohydrates derived from animals, plants, sediments, and soils provides important information about biochemical and physiological processes, past environmental conditions, and geographical origins, which are otherwise not available. Nowadays, δ(18)O analyses are often performed on carbohydrate bulk material, while compound-specific δ(18)O analyses remain challenging and methods for a wide range of individual carbohydrates are rare. To improve the δ(18)O analysis of individual carbohydrates by gas chromatography/pyrolysis-isotope ratio mass spectrometry (GC/Pyr-IRMS) we developed a new methylation derivatization method. Carbohydrates were fully methylated within 24 h in an easy-to-handle one-pot reaction in acetonitrile, using silver oxide as proton acceptor, methyl iodide as methyl group carrier, and dimethyl sulfide as catalyst. The precision of the method ranged between 0.12 and 1.09‰ for the δ(18)O values of various individual carbohydrates of different classes (mono-, di-, and trisaccharides, alditols), with an accuracy of a similar order of magnitude, despite high variation in peak areas. Based on the δ(18)O values of the main isomers, important monosaccharides such as glucose and fructose could also be precisely analyzed for the first time. We tested the method on standard mixtures, honey samples, and leaf carbohydrates extracted from Pinus sylvestris, showing that the method is also applicable to different carbohydrate mixtures. The new methylation method shows unrivalled accuracy and precision for δ(18)O analysis of various individual carbohydrates; it is fast and easy-to-handle, and may therefore find wide-spread application. Copyright © 2015 John Wiley & Sons, Ltd.

  5. δ18O of apatite phosphate in small pelagic fish: insights from wild-caught and tank-grown specimens

    Science.gov (United States)

    Lambert, T.; Javor, B.; Paytan, A.

    2011-12-01

    Oxygen isotope ratios of mineralized structures in fish reflect the temperature and isotopic composition of the water in which they grow. For bulk samples (e.g., whole scales, bones, and otoliths), understanding how this signal is integrated across time and space is critical, especially for organisms exposed to high variability in growth conditions. Here, we assess the response of fish scale δ18O (from apatite phosphate) to experimentally manipulated water conditions. Wild-caught sardines were grown at controlled temperatures (13°C, 17°C, and 21°C) for 11 months. Higher growth temperatures correlated to lower δ18O values, representing a combination of scale apatite deposited before and after the temperature manipulation. Models that account for both biomineral allometry and exposure to varying water properties (e.g., by overlaying migration routes, isoscapes, and temperature maps) have the potential to quantify the varying contributions of minerals grown under different conditions. We use this method to predict δ18O of apatite phosphate for small pelagic fish found in California coastal waters, then compare expected values to those obtained from collected samples. Since phosphate oxygen is relatively resistant to diagenesis, this modern calibration establishes a framework for paleo studies.

  6. Search for the two-photon decay of the 2+ first excited states in 18O and 28Si

    International Nuclear Information System (INIS)

    Music, M.

    1986-01-01

    The present work describes an attempt to measure the probability for the two-photon transition between two adjacent nuclear states in the presence of an allowed, strongly predominant one-photon decay, using the Heidelberg-Darmstadt Crystal Ball Spectrometer. The branching ratios of the two-photon decay of the first excited, 2 + levels of 18 O and 28 Si relative to the one-photon, E2 transitions to the 0 + ground states were determined to be: Wγγ/Wγ = (0.7±2.4) x 10 -6 for the 2 + >0 + transition in 18 O and Wγγ/Wγ = (1.6±1.8) x 10 -6 for the 2 + >0 + transition in 28 Si. Since both results are consistent with zero, it is possible to express them as the upper limits for the two-photon decay (3 δ) of 7.9 x 10 -6 of 18 O and 6.9 x 10 -6 of 28 Si 2 + levels. These values are by far the smallest ones reported to be observed in a two-photon decay of a nuclear state. For 18 O, the result disproves theoretical estimates of the corresponding two-photon E1F1 matrix element was well as experimental values deduced from multiple-Coulomb-excitation measurements. The main experimental difficulties were caused by the gamma rays from one-photon transitions and were found to be connected with cross-talk events due to Bremsstrahlung of Compton electrons and not - as generally believed - positron annihilation in flight. (orig.)

  7. Hydration of the Atlantis Massif: Halogen, Noble Gas and In-Situ δ18O Constraints

    Science.gov (United States)

    Williams, M. J.; Kendrick, M. A.; Rubatto, D.

    2017-12-01

    A combination of halogen (Cl, Br, I), noble gases (He, Ne, Ar, Kr and Xe) and in situ oxygen isotope analysis have been utilized to investigate the fluid-mobile element record of hydration and alteration processes at the Atlantis Massif (30°N on the Mid-Atlantic Ridge). The sample suite investigated includes serpentinite, talc-amphibole ± chlorite schist and hydrated gabbro recovered by seafloor drilling undertaken at sites on a transect across the Atlantis Massif during IODP Expedition 357. Serpentine mesh and veins analysed in-situ by SHRIMP SI exhibit δ18O from 6‰ down to ≈0‰, suggesting serpentinization temperatures of 150 to >280°C and water/rock ratios >5. Differences of 1.5-2.5‰ are observed between adjacent generations of serpentine, but the δ18O range is similar at each investigated drilling site. Halogen and noble gas abundances in serpentinites, talc-amphibole schist and hydrated gabbro have been measured by noble gas mass spectrometry of both irradiated and non-irradiated samples. Serpentinites contain low abundances of halogens and noble gases (e.g. 70-430 ppm Cl, 4.7-12.2 x 10-14 mol/g 36Ar) relative to other seafloor serpentinites. The samples have systematically different Br/Cl and I/Cl ratios related to their mineralogy. Serpentinites retain mantle-like Br/Cl with a wide variation in I/Cl that stretches toward seawater values. Talc-amphibole schists exhibit depletion of Br and I relative to Cl with increasing Cl abundances, suggesting tremolite exerts strong control on halogen abundance ratios. Serpentinites show no evidence of interaction with halogen-rich sedimentary pore fluids. Iodine abundances are variable across serpentinites, and are decoupled from Br and Cl; iodine enrichment (up to 530 ppb) is observed within relatively oxidised and clay-bearing samples. Serpentinized harzburgites exhibit distinct depletion of Kr and Xe relative to atmospheric 36Ar in seawater. Oxygen isotope compositions and low abundances of both halogens

  8. A Pliocene marine diatom δ18O record of terrestrial-marine feedbacks and orbitally-paced cryogenic brine formation in the McMurdo Dry Valleys

    Science.gov (United States)

    Dodd, J. P.; Abbott, T.; Gibbons, J. A.

    2017-12-01

    Orbital frequencies are well documented in a number of terrestrial and marine climate records throughout the Cenozoic; however, assessing the feedbacks and timing of terrestrial-marine systems on glacial-interglacial timescales is often challenging. This is particularly the case in high-latitude, near-shore environments where traditional proxy records like benthic foraminifera are absent. Here we present oxygen isotope (δ18O and δ17O) values from marine diatom silica in the mid-Pliocene (3.5 - 4.7Ma) section of the AND-1B core from McMurdo Sound, Antarctica. Diatom silica δ18O values range between +28.1 and +36.4‰ VSMOW. Over a range of temperatures (0 to 10°C) that reflect both growth and shallow (fall on a mixing line between marine and meteoric waters, which also supports our cryogenic brine hypothesis. The AND-1B δ18O values have an inverse relationship with the stacked benthic foraminifera δ18O record where lower δ18O values in the AND-1B diatom silica correspond with colder intervals, and we interpret variations in the diatom δ18O values as increased brine flux from the MDV to McMurdo Sound. Currently, subsurface brines in the MDV are hydrologically connected with McMurdo Sound. Density-driven transport of these brines from the MDV to the marine costal environments during the warm mid-Pliocene indicate a potentially overlooked terrestrial source of hypersaline waters. Although the lateral extent of these brines is not known, mixing between the terrestrial cryogenic brines and seawater may represent a significant flux of hypersaline water to the marine environment during warmer-than-present global conditions.

  9. Nitrogen fertilization and δ18 O of CO2 have no effect on 18 O-enrichment of leaf water and cellulose in Cleistogenes squarrosa (C4 ) - is VPD the sole control?

    Science.gov (United States)

    Liu, Hai Tao; Gong, Xiao Ying; Schäufele, Rudi; Yang, Fang; Hirl, Regina Theresia; Schmidt, Anja; Schnyder, Hans

    2016-12-01

    The oxygen isotope composition of cellulose (δ 18 O Cel ) archives hydrological and physiological information. Here, we assess previously unexplored direct and interactive effects of the δ 18 O of CO 2 (δ 18 O CO2 ), nitrogen (N) fertilizer supply and vapour pressure deficit (VPD) on δ 18 O Cel , 18 O-enrichment of leaf water (Δ 18 O LW ) and cellulose (Δ 18 O Cel ) relative to source water, and p ex p x , the proportion of oxygen in cellulose that exchanged with unenriched water at the site of cellulose synthesis, in a C 4 grass (Cleistogenes squarrosa). δ 18 O CO2 and N supply, and their interactions with VPD, had no effect on δ 18 O Cel , Δ 18 O LW , Δ 18 O Cel and p ex p x . Δ 18 O Cel and Δ 18 O LW increased with VPD, while p ex p x decreased. That VPD-effect on p ex p x was supported by sensitivity tests to variation of Δ 18 O LW and the equilibrium fractionation factor between carbonyl oxygen and water. N supply altered growth and morphological features, but not 18 O relations; conversely, VPD had no effect on growth or morphology, but controlled 18 O relations. The work implies that reconstructions of VPD from Δ 18 O Cel would overestimate amplitudes of VPD variation, at least in this species, if the VPD-effect on p ex p x is ignored. Progress in understanding the relationship between Δ 18 O LW and Δ 18 O Cel will require separate investigations of p ex and p x and of their responses to environmental conditions. © 2016 John Wiley & Sons Ltd.

  10. Water and nitrogen conditions affect the relationships of Delta13C and Delta18O to gas exchange and growth in durum wheat.

    Science.gov (United States)

    Cabrera-Bosquet, Llorenç; Molero, Gemma; Nogués, Salvador; Araus, José Luis

    2009-01-01

    Whereas the effects of water and nitrogen (N) on plant Delta(13)C have been reported previously, these factors have scarcely been studied for Delta(18)O. Here the combined effect of different water and N regimes on Delta(13)C, Delta(18)O, gas exchange, water-use efficiency (WUE), and growth of four genotypes of durum wheat [Triticum turgidum L. ssp. durum (Desf.) Husn.] cultured in pots was studied. Water and N supply significantly increased plant growth. However, a reduction in water supply did not lead to a significant decrease in gas exchange parameters, and consequently Delta(13)C was only slightly modified by water input. Conversely, N fertilizer significantly decreased Delta(13)C. On the other hand, water supply decreased Delta(18)O values, whereas N did not affect this parameter. Delta(18)O variation was mainly determined by the amount of transpired water throughout plant growth (T(cum)), whereas Delta(13)C variation was explained in part by a combination of leaf N and stomatal conductance (g(s)). Even though the four genotypes showed significant differences in cumulative transpiration rates and biomass, this was not translated into significant differences in Delta(18)O(s). However, genotypic differences in Delta(13)C were observed. Moreover, approximately 80% of the variation in biomass across growing conditions and genotypes was explained by a combination of both isotopes, with Delta(18)O alone accounting for approximately 50%. This illustrates the usefulness of combining Delta(18)O and Delta(13)C in order to assess differences in plant growth and total transpiration, and also to provide a time-integrated record of the photosynthetic and evaporative performance of the plant during the course of crop growth.

  11. Calibration of δ13C and δ18O measurements in CO2 using Off-axis Integrated Cavity Output Spectrometer (ICOS)

    Science.gov (United States)

    Joseph, Jobin; Külls, Christoph

    2014-05-01

    The δ13C and δ18O of CO2 has enormous potential as tracers to study and quantify the interaction between the water and carbon cycles. Isotope ratio mass spectrometry (IRMS) being the conventional method for stable isotopic measurements, has many limitations making it impossible for deploying them in remote areas for online or in-situ sampling. New laser based absorption spectroscopy approaches like Cavity Ring Down Spectroscopy (CRDS) and Integrated Cavity Output Spectroscopy (ICOS) have been developed for online measurements of stable isotopes at an expense of considerably less power requirement but with precision comparable to IRMS. In this research project, we introduce a new calibration system for an Off- Axis ICOS (Los Gatos Research CCIA-36d) for a wide range of varying concentrations of CO2 (800ppm - 25,000ppm), a typical CO2 flux range at the plant-soil continuum. The calibration compensates for the concentration dependency of δ13C and δ18O measurements, and was performed using various CO2 standards with known CO2 concentration and δC13 and δO18 values. A mathematical model was developed after the calibration procedure as a correction factor for the concentration dependency of δ13C and δ18O measurements. Temperature dependency of δ13C and δ18O measurements were investigated and no significant influence was found. Simultaneous calibration of δ13C and δ18O is achieved using this calibration system with an overall accuracy of (~ 0.75±0.24 ‰ for δ13C, ~ 0.81 ±0.26‰ for δ18O). This calibration procedure is found to be appropriate for making Off-Axis ICOS suitable for measuring CO2 concentration and δ13C and δ18O measurements at atmosphere-plant-soil continuum.

  12. Within-canopy and ozone fumigation effects on delta13C and Delta18O in adult beech (Fagus sylvatica) trees: relation to meteorological and gas exchange parameters.

    Science.gov (United States)

    Gessler, Arthur; Löw, Markus; Heerdt, Christian; de Beeck, Maarten Op; Schumacher, Johannes; Grams, Thorsten E E; Bahnweg, Günther; Ceulemans, Reinhart; Werner, Herbert; Matyssek, Rainer; Rennenberg, Heinz; Haberer, Kristine

    2009-11-01

    In this study, the effects of different light intensities either in direct sunlight or in the shade crown of adult beech (Fagus sylvatica L.) trees on delta13C and Delta18O were determined under ambient (1 x O3) and twice-ambient (2 x O3) atmospheric ozone concentrations during two consecutive years (2003 and 2004). We analysed the isotopic composition in leaf bulk, leaf cellulose, phloem and xylem material and related the results to (a) meteorological data (air temperature, T and relative humidity, RH), (b) leaf gas exchange measurements (stomatal conductance, g(s); transpiration rate, E; and maximum photosynthetic activity, A(max)) and (c) the outcome of a steady-state evaporative enrichment model. Delta13C was significantly lower in the shade than in the sun crown in all plant materials, whilst Delta18O was increased significantly in the shade than in the sun crown in bulk material and cellulose. Elevated ozone had no effect on delta13C, although Delta18O was influenced by ozone to varied degrees during single months. We observed significant seasonal changes for both parameters, especially in 2004, and also significant differences between the study years. Relating the findings to meteorological data and gas exchange parameters, we conclude that the differences in Delta18O between the sun and the shade crown were predominantly caused by the Péclet effect. This assumption was supported by the modelled Delta18O values for leaf cellulose. It was demonstrated that independent of RH, light-dependent reduction of stomatal conductance (and thus transpiration) and of A(max) can drive the pattern of Delta18O increase with the concomitant decrease of delta13C in the shade crown. The effect of doubling ozone levels on time-integrated stomatal conductance and transpiration as indicated by the combined analysis of Delta18O and delta13C was much lower than the influence caused by the light exposure.

  13. Elastic and inelastic scattering of 18O ions on 12C nuclei

    Directory of Open Access Journals (Sweden)

    A. T. Rudchik

    2009-12-01

    Full Text Available Angular distributions of the 12C + 18O elastic and inelastic scattering were measured at the energy Elab(18O = 105 MeV (Ec.m. = 42 MeV. These data and data known from the literature at the energies Ec.m. = 12.9 - 56 МеV were analysed within the optical model and coupled-reactionchannels method. The sets of the Woods-Saxon (12С + 18O-potential parameters were deduced and their energy dependence was studied. It was found the isotopic differences in the (12С + 16O- and (12С + 18O-potentials parameters and in their surface forms. The mechanisms of elastic and inelastic (12С + 18O-scattering and role of transfer reactions were studied.

  14. Stable isotope variations (δ18O and δD) in modern waters across the Andean Plateau

    Science.gov (United States)

    Bershaw, John; Saylor, Joel E.; Garzione, Carmala N.; Leier, Andrew; Sundell, Kurt E.

    2016-12-01

    Environmental parameters that influence the isotopic composition of meteoric water (δ18O and δD) are well characterized up the windward side of mountains, where orographic precipitation results in a predictable relationship between the isotopic composition of precipitation and elevation. The topographic and climatic evolution of the Andean Plateau and surrounding regions has been studied extensively by exploiting this relationship through the use of paleowater proxies. However, interpretation on the plateau itself is challenged by a poor understanding of processes that fractionate isotopes during vapor transport and rainout, and by the relative contribution of unique moisture sources. Here, we present an extensive dataset of modern surface water samples for the northern Andean Plateau and surrounding regions to elucidate patterns and causes of isotope fractionation in this continental environment. These data show a progressive increase in δ18O of stream water west of the Eastern Cordillera (∼1‰/70 km), almost identical to the rate observed across the Tibetan Plateau, attributed to a larger fraction of recycled water in precipitation and/or increased evaporative enrichment downwind. This may lead to underestimates of paleoelevation, particularly for sites deep into the rainshadow of the Eastern Cordilleran crest. That said, elevation is a primary control on the isotopic composition of surface waters across the entire Andean Plateau and its flanks when considering the most negative δ18O values, highlighting the need for sufficiently large datasets to distinguish minimally evaporated samples. There is a general increase in δ18O on the plateau from north to south, concomitant with an increase in aridity and decrease in convective moistening (amount effect). Lastly, stable isotope and seasonal precipitation patterns suggest easterlies provide the vast majority of moisture that falls as precipitation across the Andean Plateau and Western Cordillera, from Peru to

  15. Destruction of /sup 18/O in red giants. A search for a sub-threshold resonance in the /sup 18/O+p system

    Energy Technology Data Exchange (ETDEWEB)

    Champagne, A E; Pitt, M L

    1986-09-08

    The /sup 18/O(/sup 3/He,d)/sup 19/F reaction has been used to determine if a presumed sub-threshold resonance at Esub(c.m.)=-94 KeV in the /sup 18/O(p,..cap alpha..)/sup 15/N reaction exists at an astrophysically significant level. No evidence for this state was observed which implies a dimensionless reduced width thetasub(p)/sup 2/<5 . 10/sup -5/. In addition, a proton width GAMMAsub(p)=2 x 10/sup -19/ eV has been determined for a d-wave resonance located at Esub(c.m.)=20 keV. The resulting thermonuclear reaction rate is slow enough to ensure that /sup 18/O is not destroyed at red-giant temperatures.

  16. Doubly Labelled Water analysis : Preparation, memory correction, calibration and quality assurance for delta δ2H and δ18O measurements over four orders of magnitudes

    NARCIS (Netherlands)

    Guidotti, S.; Jansen, H.G.; Aerts-Bijma, A.T.; Verstappen-Dumoulin, B.M.A.A.; van Dijk, G.; Meijer, H.A.J.

    2013-01-01

    RATIONALE The Doubly Labelled Water (DLW) method is an established way of determining the metabolic rate in humans and animals, with the advantage that the subjects need not be confined. The method, however, needs accurate determination of both the 2H and the 18O isotope values over a wide range of

  17. Evaluating the source of streamwater nitrate using d15N and d18O in nitrate in two watersheds in New Hampshire, USA

    Science.gov (United States)

    Linda H. Pardo; Carol Kendall; Jennifer Pett-Ridge; Cecily C.Y. Chang; Cecily C.Y. Chang

    2004-01-01

    The natural abundance of nitrogen and oxygen isotopes in nitrate can be a powerful tool for identifying the source of nitrate in streamwater in forested watersheds, because the two main sources of nitrate, atmospheric deposition and microbial nitrification, have distinct d18O values. Using a simple mixing model, we estimated the relative fractions in streamwater...

  18. In situ TEM observation of the growth and decomposition of monoclinic W18O49 nanowires

    International Nuclear Information System (INIS)

    Chen, C L; Mori, H

    2009-01-01

    The growth of monoclinic W 18 O 49 nanowires by heat treatment of a tungsten filament at ∼873 K and the decomposition of these nanowires under 200 keV electron irradiation at ∼1023 K have been investigated using in situ transmission electron microscopy (TEM). In situ TEM observation of the growth confirmed the vapor-solid growth mechanism of the monoclinic W 18 O 49 nanowires. In situ irradiation experiments revealed the formation of metallic bcc tungsten from monoclinic W 18 O 49 nanowires under 200 keV electron irradiation.

  19. Implications of the 14C(α,γ)18O reaction for nonstandard big bang nucleosynthesis

    International Nuclear Information System (INIS)

    Gai, M.

    1992-01-01

    The thermonuclear burning rates for the 14 C(α,γ) 18 O radiative capture reaction are calculated at temperatures (0.3 - state, at approximately 9.0 MeV in 18 O as would be deduced from the Yale-Michigan State University measurement of the beta-delayed alpha-particle emission of 18 N and suggested by the Notre Dame-Caltech measurement of the nonresonant 14 C(α,γ) 18 O cross section. The gamma widths of the proposed broad state is estimated using the Alhassid, Gai, and Bertsch sum rule, and an experimental study is proposed

  20. TDA's validity to study 18O collectivity in terms of collective pair model

    International Nuclear Information System (INIS)

    Gao Yuanyi; Vitturi, A.; Catara, F.; Sambataro, M.

    1991-01-01

    Conclusion proved that if the authors calculate 18 O collective spectra in terms of the Collective Pair Model, the authors can get the positive low laying levels of 18 O which are of the particle particle pair, independent on the excitation of hole within closed shell. 1 - low laying levels are of non-collective 3 particle 1 hole states. 1 - fourth level is of collective 3 particle 1 hole states. 3 - low laying levels are of collective 3 particle 1 hole states. 1 - , 3 - low laying levels agree very well with the experiment data. Hence the TDA is sufficient for the calculations of 1 - ,3 - collective low levels of 18 O

  1. 雅鲁藏布江流域降水中氧稳定同位素的时空变化%Temporal and spatial variations of δ18O in precipitation of the Yarlung Zangbo River Basin

    Institute of Scientific and Technical Information of China (English)

    刘忠方; 田立德; 姚檀栋; 巩同梁; 尹常亮; 余武生

    2007-01-01

    This paper reveals the temporal and spatial variations of stable isotope in precipitation of the Yarlung Zangbo River Basin based on the variations ofδ18O in precipitation at four stations (Lhaze, Nugesha, Yangcun and Nuxia) in 2005. The results show thatδ18O of precipitation has distinct seasonal changes in the Yarlung Zangbo River Basin. The higher value of δ18O occurs in spring prior to monsoon precipitation, and the lower value occurs during monsoon precipitation. From the spatial variations, with the altitude-effect and rainout process during moisture transport along the Yarlung Zangbo River Valley, 18O of precipitation is gradually depleted. Thus, δ18O of precipitation decreases gradually from the downstream to the upstream, and the lapse rate of δ18O in precipitation is approximately 0.34%o/100m and 0.7%o/100km for the two reasons. During monsoon precipitation, spatial variation of δ18O in precipitation is dominated by the amount effect in the large scale synoptic condition.

  2. Impact of carbohydrate supply on stem growth, wood and respired CO{sub 2} {delta}{sup 13}C : assessment by experimental girdling

    Energy Technology Data Exchange (ETDEWEB)

    Maunoury-Danger, F. [Paris-Sud Univ., Orsay Cedex (France). Laboratoire Ecologie, Systematique et Evolution; Centre National de la Recherche Scientifique, Orsay CEDEX (France); AgroParisTech, Paris (France); Paul Verlaine-Metz Univ., Metz (France). Laboratoire des Interactions Ecotoxicologie Biodiversite Ecosystemes; Fresneau, C.; Eglin, T.; Berveiller, D.; Francois, C.; Damesin, C. [Paris-Sud Univ., Orsay Cedex (France). Laboratoire Ecologie, Systematique et Evolution; Centre National de la Recherche Scientifique, Orsay CEDEX (France); AgroParisTech, Paris (France); Lelarge-Trouverie, C. [Paris-Sud Univ., Orsay Cedex (France). Inst. de Biotechnologie des Plantes, Plateforme Metabolisme-Metabolome

    2010-07-15

    In trees, carbohydrate storage and remobilization may affect the carbon isotope signals of sugars exported from leaves, tree organic matter and respired carbon dioxide (CO{sub 2}). This study characterized the impact of a change in the carbon (C) source used for stem functioning on the {delta}{sup 13} C of stem organic matter and respired CO{sub 2}. Girdling experiments were carried out on 2-year old oaks that consisted in removing the bark and phloem around the stem so that the sap would cease to flow. The stem was therefore forced to use its own C reserves to maintain metabolic activity. Trees were girdled at 3 different periods, notably just after budburst, during stem growth, and just after cessation of stem radial growth. Stem radial growth and respiration rate were measured throughout the year. Other measured variables included {delta}{sup 13} C of respired CO{sub 2} and contents of starch and water-soluble fraction in stems and leaves. The study showed that girdling stopped growth, even early in the growing season, leading to a decrease in stem CO{sub 2} efflux. The study demonstrated that leaf carbohydrate supply versus reserve use could be an important factor controlling stem growth and {delta}{sup 13} C of both ring and stem CO{sub 2} efflux. 69 refs., 3 tabs., 5 figs.

  3. Reconstruction of water mass properties of the Western Mediterranean using stable isotope ratios (δ18O and δ13C) from Pinna nobilis shells

    Science.gov (United States)

    Garcia-March, Jose Rafael; Surge, Donna; Tena-Medialdea, Jose; Torres, Javi; Garcia-Martinez, Micaela

    2017-04-01

    We analysed the stable isotope ratios (δ18O and δ13C) from the calcite of the outer prismatic layer of 8 Pinna nobilis shells at a rate of c. 12-16 samples/year for years between 1997 and 2013. These produced 8 time series between 4 and 16 years long. The empty shells had been collected in two Spanish marine protected areas, Tabarca Island in Alicante and Columbretes Islands in Castellón (4 specimens each). For all shells we constrained the time of death within at least a halve year window. The present study completes previous calibrations by using recorded seawater temperature data during at least two years for each site, coinciding with part of the analysed periods in the shells. Our preliminary results clearly reflect the seasonality of the signal in δ18O values for the entire ontogeny of the individuals studied. However, one specimen from Tabarca Island sampled between years 4 and 11 (corresponding to real age) shows a clear ontogenetic change, with an abrupt reduction in the amplitude of the signal from age 6 to 11 for both δ18O and δ13C values. We hypothesize this pattern relates to the onset of first gonad maturation. Values of δ13C track δ18O values in most individuals, but 3 specimens show low amplitude. For all time series, δ13C values show a decreasing slope with ontogeny similar to previous observations in P. nobilis and other bivalves. Estimated seawater temperature from our δ18O time series reveals the potential of P. nobilis shells as valuable archives of Mediterranean temperature reconstructions in the context of climate change.

  4. The effect of acid rain and altitude on concentration, δ34S, and δ18O of sulfate in the water from Sudety Mountains, Poland

    Science.gov (United States)

    Szynkiewicz, Anna; Modelska, Magdalena; Jedrysek, Mariusz Orion; Mastalerz, Maria

    2008-01-01

    The analyses of sulfate content, δ34S and δ18O of dissolved sulfate, and δ18O of water were carried out in a 14 km2 crystalline massif located in the Sudety Mountains (SW Poland) to 1) assess the amount of the sulfate delivered to the surface and groundwater systems by modern atmospheric precipitation, 2) determine the effect of altitude on these parameters, and 3) investigate their seasonal variations. In April and November of 2002, August 2003, and March and September of 2005, samples of water were collected from springs and streams of the massif. During these seasons, sulfate contents and δ18O(SO42−) values varied from 5.80 to 18.00 mg/l and from 3.96 to 8.23‰, respectively, showing distinctively higher values ofδ18O(SO42−) in wet seasons. The δ34S(SO42−) values had a relatively narrow range from 4.09 to 5.28‰ and were similar to those reported for organic matter in soil and the canopy throughfall in the Sudety Mountains.

  5. Secas Island Stable Isotope Data (delta 18O) for 1707 to 1984

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Secas Island Coral d18O, used to reconstruct seasonal and interannual variability in the Intertropical Convergence Zone. Site Location: Secas Island, Gulf of...

  6. Malindi, Kenya Stable Isotope Data (delta 18O, delta 13C) for 1801-1994

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Malindi annual oxygen isotopic composition, 1801-1994. Notes on the data: File includes columns for Year AD, Coral d18O, and SST (degrees C). The SST data are sparse...

  7. Barbados Oxygen Isotope Data (delta 18O) for the Late Pleistocene

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Coral-based delta18O time-series derived from measurements made on submerged or drowned coral reef sequence. The core samples used have been described elsewhere (cf....

  8. Development of a technique for mass spectrometric measurement of δ18O of aqueous sulphate

    International Nuclear Information System (INIS)

    Kulkarni, U.P.; Sharma, Suman

    2003-01-01

    Application of stable isotopes of hydrogen and oxygen as tracers in hydrology for studying the origin of water is well established. δ 18 O of water molecule itself is used for identifying the source of water whereas δ 18 O of dissolved oxy anions (such as carbonate, phosphate, sulphate, nitrate and silicate) present in the same water reveal their source of origin. δ 18 O of SO 4 finds applications in identifying the origin of sulfate i.e. marine, marine evaporite or non-marine in nature and as a geothermometer in determining subsurface temperature of geothermal waters. A vacuum line of glass was fabricated to measure δ 18 O of aqueous sulfate. This paper deals with the technique and results of a trial with NBS-127, Sea water barium sulfate

  9. Ras Umm Sidd Oxygen Isotope (delta 18O) Data for 1750 to 1995

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Ras Umm Sidd bimonthly coral oxygen isotope data (coral core RUS-95). Notes on the data: File (Ras Umm Sidd d18O.txt.) includes columns for Year AD (bimonthly...

  10. Simulation and optimization of stable isotope 18O separation by cascade distillation

    International Nuclear Information System (INIS)

    Jiang Yongyue; Chen Yuyan; Qin Chuanjiang; Liu Yan; Gu Hongsen

    2011-01-01

    The research about started from the plan of four cascade towers design was carried. Firstly, the method of experiment design was using uniform design. Then the incidence formula with the method of binomial stepwise regression was gotten. Last, the optimal operation conditions were gotten by using the method of genetic algorithm. Considering comprehensive factors of drawn from feed rate and from flow rates between cascade column, conclusions were reached on the study of the impact on the abundance of the isotope 18 O. Finally, the incidence formula between the abundance of the isotope 18 O and four operating variables were gotten. Also the incidence formula between heat consumption of the isotope 18 O and four operating variables were gotten. Besides, single factor response diagram of four factors were shown at last. The results showed that the method of simulation and optimization could be applied to 18 O industrial design and would be popular in traditional distillation process to realize optimization design. (authors)

  11. The effect of prior hydrothermal alteration on the melting behaviour during rhyolite formation in Yellowstone, and its importance in the generation of low-δ18O magmas

    Science.gov (United States)

    Troch, Juliana; Ellis, Ben S.; Harris, Chris; Ulmer, Peter; Bachmann, Olivier

    2018-01-01

    Constraining the contribution of crustal lithologies to silicic magmas has important implications for understanding the dynamics of these potentially highly explosive systems. Low-δ18O rhyolite lavas erupted after caldera-forming events in Yellowstone have been interpreted as the products of bulk crustal melting of previously deposited and hydrothermally altered rhyolitic material in the down-dropped caldera roof. For lack of compositional data, the "self-cannibalisation bulk melting"-theory relies on the assumption that hydrothermally altered materials are near-cotectic and hydrous (>3 wt% H2O) and will therefore readily melt at temperatures below 850 °C. In this study, we examine the drillcores Y2, Y9 and Y13 from a USGS drilling campaign in Yellowstone in order to characterise the hydrothermally altered material in terms of major and trace elements, oxygen isotopes and water contents. Rhyolite δ18O values can decrease from "normal" (+5.8 to +6.1‰) on the surface to as low as -5‰ at depths of 100-160 m and probably lower as a function of increasing temperature with depth. While material in the drillcores is variably altered and silicified, oxygen isotope exchange in these samples is not accompanied by systematic changes in major and trace element composition and is independent of uptake of water. More than 75% of the drillcore samples have 1100 °C. Therefore, large-scale bulk melting is unrealistic and low-δ18O rhyolite magmas more likely result from assimilation of <30% partially melted altered crust with low δ18O into a normal-δ18O rhyolite magma from the main reservoir. This mechanism is supported by isotopic mass-balance models as well as thermal and volumetric constraints, and may be similarly applicable to other low-δ18O settings worldwide.

  12. Regional Scale High Resolution δ18O Prediction in Precipitation Using MODIS EVI

    Science.gov (United States)

    Huang, Cho-Ying; Wang, Chung-Ho; Lin, Shou-De; Lo, Yi-Chen; Huang, Bo-Wen; Hatch, Kent A.; Shiu, Hau-Jie; You, Cheng-Feng; Chang, Yuan-Mou; Shen, Sheng-Feng

    2012-01-01

    The natural variation in stable water isotope ratio data, also known as water isoscape, is a spatiotemporal fingerprint and a powerful natural tracer that has been widely applied in disciplines as diverse as hydrology, paleoclimatology, ecology and forensic investigation. Although much effort has been devoted to developing a predictive water isoscape model, it remains a central challenge for scientists to generate high accuracy, fine scale spatiotemporal water isoscape prediction. Here we develop a novel approach of using the MODIS-EVI (the Moderate Resolution Imagining Spectroradiometer-Enhanced Vegetation Index), to predict δ18O in precipitation at the regional scale. Using a structural equation model, we show that the EVI and precipitated δ18O are highly correlated and thus the EVI is a good predictor of precipitated δ18O. We then test the predictability of our EVI-δ18O model and demonstrate that our approach can provide high accuracy with fine spatial (250×250 m) and temporal (16 days) scale δ18O predictions (annual and monthly predictabilities [r] are 0.96 and 0.80, respectively). We conclude the merging of the EVI and δ18O in precipitation can greatly extend the spatial and temporal data availability and thus enhance the applicability for both the EVI and water isoscape. PMID:23029053

  13. Fourier Transform Spectroscopy of 18O-Enriched Carbonyl Sulfide from 1825 to 2700 cm -1

    Science.gov (United States)

    Strugariu, T.; Naı̈m, S.; Fayt, A.; Bredohl, H.; Blavier, J.-F.; Dubois, I.

    1998-06-01

    We have measured the Fourier transform spectrum of carbonyl sulfide from 1825 to 2700 cm-1, using a sample enriched in both18O (94.0%) and17O (1.54%). A careful calibration yields a line-position accuracy between 1.5 and 3.0 10-5cm-1. We have observed and analyzed 118 infrared bands of which 93 are measured for the first time: 55 for18O12C32S, 20 for18O12C34S, 11 for18O12C33S, 1 for18O12C36S, 12 for17O12C32S, 4 for17O12C34S, 2 for17O12C33S, and 13 for18O13C32S. Intensities are also reported and analyzed for all those bands. The intensity accuracy is better than 10%, and the precision of approximately 1% allows us to determine some Herman-Wallis coefficients.

  14. Simulation and optimization of stable isotope 18O separation by water vacuum distillation

    International Nuclear Information System (INIS)

    Chen Yuyan; Qin Chuanjiang; Xiao Bin; Xu Jing'an

    2012-01-01

    In the research, a stable isotope 18 O separation column was set up by water vacuum distillation with 20 m packing height and 0.1 m diameter of the column. The self-developed special packing named PAC- 18 O was packed inside the column. Firstly, a model was created by using the Aspen Plus software, and then the simulation results were validated by test results. Secondly, a group of simulation results were created by Aspen Plus, and the optimal operation conditions were gotten by using the artificial neural network (ANN) and Statistica software. Considering comprehensive factors drawn from column pressure and from withdrawing velocity, conclusions were reached on the study of the impact on the abundance of the isotope 18 O. The final results show that the abundance of the isotope 18 O increases as column pressure dropping and withdrawing velocity decreasing. Besides, the optimal column pressure and the incidence formula between the abundance of the isotope 18 O and withdrawing velocity were gotten. The conclusion is that the method of simulation and optimization can be applied to 18 O industrial design and will be popular in traditional distillation process to realize optimization design. (authors)

  15. Leaf anatomical traits determine the 18O enrichment of leaf water in coastal halophytes

    Science.gov (United States)

    Liang, J.; Lin, G., Sr.; Sternberg, L. O.

    2017-12-01

    Foliar anatomical adaptations to high-salinity environment in mangroves may be recorded by leaf water isotopes. Recent studies observed that a few mangrove species have lower 18O enrichment of leaf water (ΔL) relative to source water than the adjacent terrestrial trees, but what factors actually control this phenomenon is still disputable at present. To resolve this issue, we collected 15 species of true mangrove plants, 14 species of adjacent freshwater trees and 4 species of semi-mangrove plants at five study sites on the southeastern coast of China. Leaf stomatal density and pore size, water content, ΔL and other related leaf physiological traits were determined for the selected leaves of these plants. Our results confirmed that ΔL values of mangroves were generally 3 4 ‰ lower than those of the adjacent freshwater or semi-mangrove species. Higher leaf water per area (LWC) and lower leaf stomatal density (LS) of mangroves played co-dominant roles in lowering ΔL through elongating effective leaf mixing length by about 20%. The Péclet model incorporated by LWC and LS performed well in predicting ΔL. The demonstrated general law between leaf anatomy and ΔL in this paper based on a large pool of species bridges the gap between leaf functional traits and metabolic proxies derived ΔL, which will have considerable potential applications in vegetation succession and reconstruction of paleoclimate research.

  16. High-precision determination of 18O/16O ratios of silver phosphate by EA-pyrolysis-IRMS continuous flow technique.

    Science.gov (United States)

    Lécuyer, Christophe; Fourel, François; Martineau, François; Amiot, Romain; Bernard, Aurélien; Daux, Valérie; Escarguel, Gilles; Morrison, John

    2007-01-01

    A high-precision, and rapid on-line method for oxygen isotope analysis of silver phosphate is presented. The technique uses high-temperature elemental analyzer (EA)-pyrolysis interfaced in continuous flow (CF) mode to an isotopic ratio mass spectrometer (IRMS). Calibration curves were generated by synthesizing silver phosphate with a 13 per thousand spread in delta(18)O values. Calibration materials were obtained by reacting dissolved potassium dihydrogen phosphate (KH(2)PO(4)) with water samples of various oxygen isotope compositions at 373 K. Validity of the method was tested by comparing the on-line results with those obtained by classical off-line sample preparation and dual inlet isotope measurement. In addition, silver phosphate precipitates were prepared from a collection of biogenic apatites with known delta(18)O values ranging from 12.8 to 29.9 per thousand (V-SMOW). Reproducibility of +/- 0.2 per thousand was obtained by the EA-Py-CF-IRMS method for sample sizes in the range 400-500 microg. Both natural and synthetic samples are remarkably well correlated with conventional (18)O/(16)O determinations. Silver phosphate is a very stable material and easy to degas and, thus, could be considered as a good candidate to become a reference material for the determination of (18)O/(16)O ratios of phosphate by high-temperature pyrolysis. Copyright 2006 John Wiley & Sons, Ltd.

  17. Late-Holocene hydroclimate and atmospheric circulation variability in southern Patagonia: insights from triple stable isotopes (δ18O, δ13C, δD) of peat bog Sphagnum moss

    Science.gov (United States)

    Xia, Z.; Yu, Z.; Zheng, Y.; Loisel, J.; Huang, Y.

    2017-12-01

    The Southern Hemisphere Westerly Winds (SHWWs) exert important influences on regional and global climates, but their long-term behaviors and dynamics are still poorly understood but critical for projecting future changes. Here we present a 5,500-year record from a Sphagnum-dominated peat bog located on the lee side of the Andes at 54.2 °S in southern Patagonia—based on plant macrofossils, Sphagnum cellulose δ18O and δ13C, and lipid δD data—to document and understand the variability in hydroclimate and atmospheric circulation. There is a striking negative correlation between cellulose δ18O and the Southern Annular Mode (SAM) index over the last millennium; particularly the 2.5‰ negative shift of δ18O is concurrent with the observed positive trend in the SAM over the recent decades. The interval of Medieval Climate Anomaly (MCA, 850-600 yr BP) is characterized by a 2.5‰ negative shift of δ18O and low δ13C values, while the Little Ice Age (LIA, 500-300 yr BP) is characterized by a 2.5‰ positive shift of δ18O and high δ13C values. Furthermore, we find the largest negative shift of δ18O ( 3‰) at 2,300 yr BP, suggesting a significantly positive shift in the SAM. We interpret high Sphagnum abundance and high cellulose δ13C values to reflect great moss moisture conditions, while cellulose δ18O variations primarily reflect moisture sources and atmospheric circulation. During the positive phase of SAM (e.g., the MCA and recent decades), strengthened SHWWs enhance the rain-shadow effect, resulting in dry climate and 18O-depleted precipitation (low δ18O values) in the study region. During the negative phase of SAM (e.g., the LIA), weakened SHWWs reduce rain-shadow effect, resulting in wet climate and high δ18O values caused by increases in moisture contributions from the southerly and easterly flows that do not experience strong Rayleigh distillation process during air mass transports. Furthermore, coupling cellulose δ18O and lipid δD enables

  18. δ18O analysis of individual carbohydrates - a new method for GC-pyrolysis-IRMS

    Science.gov (United States)

    Lehmann, Marco M.; Fischer, Maria; Zech, Michael; Siegwolf, Rolf T. W.; Saurer, Matthias

    2015-04-01

    Measuring the oxygen isotopic composition (δ18O) of various plant tissues is a widely used tool to investigate biochemical and physiological processes. While we have a good understanding about the hydrological cycle in plants with an evaporative enrichment in 18O in leaf water, we still lack knowledge about the biochemical link between the oxygen atoms in leaf water, leaf assimilates, and stem cellulose and associated isotope fractionations. Especially, the influence of different environmental factors on δ18O of individual carbohydrates (i.e. sugars) and thus on δ18O of cellulose is not fully resolved. A better understanding of these processes may improve climatic reconstructions of tree-ring studies about past environmental conditions. However, further progress in this topic is limited since a precise and reliable method to determine δ18O of individual sugars has not been available yet. With our new approach we attempt to overcome this issue by establishing a new methylation derivatization method suitable for GC-pyrolysis -IRMS. A methyl group (CH3) was thereby added to all hydroxyl groups of a sugar (e.g., glucose, fructose, and sucrose) during a catalyzed one-pot reaction overnight in acetonitrile with methyl iodide (CH3-I) and silver oxide, making them amenable for GC analysis. First results show a very good precision for δ18O of sucrose, but also δ18O of other high-abundant sugars such as glucose and fructose could be measured for the first time. We successfully analyzed a standard mix of all three sugars and determined various other carbohydrates not only related to plant sciences (e.g. mannitol, lactose), showing promising δ18O results. First tests with real plant samples were performed to make this method available for determining δ18O of individual carbohydrates of diverse plant tissues. In future, this new methylation derivatization method should allow us analyzing plant samples of different field sites and of lab experiments to investigate the

  19. A 242-year seasonal-resolved speleothem record from Hainan Island: A window into variability of the precipitation δ18O in East Asia

    Science.gov (United States)

    Cai, Y.; An, Z.; Cheng, H.; Edwards, R. L.; Fung, I. Y.; Zhang, H.; Tan, L.; Bi, H.

    2016-12-01

    Hainan Island is located at the gateway of East Asian summer monsoon to the continent. The typical tropical monsoon climate at Hainan island is characterized by wet season during the summer and autumn and dry season during the winter and spring. Here, we present a seasonal resolved speleothem record spanning 242 years ( 50-292 AD) from Xianren Cave (E109°25`, N18°34`), which is situated in the Baoting County, Hainan Province. The monitoring inside the cave shows that the relative humidity kept saturated during the observed periods (one and half years) while the temperature varied seasonally following the temperature changes outside the cave, but with much smaller amplitude. Monthly observation of drip water inside the cave indicates that the isotope composition of drip water mainly responds to the changes in the precipitation isotope composition with less than two months' resident time. The visible annual lamination and distinct fluctuations of calcite Mg, Sr and Ba concentrations corroborate that the high-frequency oscillations of calcite δ18O largely capture the seasonal variation of the isotope composition of precipitation, although the temperature effect cannot be excluded. By setting the heaviest value of annual variation of calcite δ18O as the beginning of each annual cycle, we transferred the δ18O record of 11.2 cm in depth to a δ18O record of 242-year in age. The δ18O record of stalagmite XR-3 demonstrate clearly the annual, decadal and multi-decadal variations of amplitude from 2 to 4‰, in addition to the seasonal oscillation of amplitude varied from 1.5 to 2.5‰. The ensemble empirical mode decomposition results show that the dominant variability (54.6% of the total variance) is captured by the components at the timescale of 3-7 year, while the components on timescales of 22-24 -year, 80-year and 120-year capture 35.0%, 7.0% and 3.4% of the variance, respectively. We contribute the variability of speleothem δ18O at the timescale of 3-7 -year to

  20. Novel time-dependent vascular actions of {delta}{sup 9}-tetrahydrocannabinol mediated by peroxisome proliferator-activated receptor gamma

    Energy Technology Data Exchange (ETDEWEB)

    O' Sullivan, Saoirse E [School of Biomedical Sciences, E Floor, Queen' s Medical Centre, University of Nottingham, Nottingham NG7 2UH (United Kingdom); Tarling, Elizabeth J [School of Biomedical Sciences, E Floor, Queen' s Medical Centre, University of Nottingham, Nottingham NG7 2UH (United Kingdom); Bennett, Andrew J [School of Biomedical Sciences, E Floor, Queen' s Medical Centre, University of Nottingham, Nottingham NG7 2UH (United Kingdom); Kendall, David A [School of Biomedical Sciences, E Floor, Queen' s Medical Centre, University of Nottingham, Nottingham NG7 2UH (United Kingdom); Randall, Michael D [School of Biomedical Sciences, E Floor, Queen' s Medical Centre, University of Nottingham, Nottingham NG7 2UH (United Kingdom)

    2005-11-25

    Cannabinoids have widespread effects on the cardiovascular system, only some of which are mediated via G-protein-coupled cell surface receptors. The active ingredient of cannabis, {delta}{sup 9}-tetrahydrocannabinol (THC), causes acute vasorelaxation in various arteries. Here we show for the first time that THC also causes slowly developing vasorelaxation through activation of peroxisome proliferator-activated receptors gamma (PPAR{gamma}). In vitro, THC (10 {mu}M) caused time-dependent vasorelaxation of rat isolated arteries. Time-dependent vasorelaxation to THC was similar to that produced by the PPAR{gamma} agonist rosiglitazone and was inhibited by the PPAR{gamma} antagonist GW9662 (1 {mu}M), but not the cannabinoid CB{sub 1} receptor antagonist AM251 (1 {mu}M). Time-dependent vasorelaxation to THC requires an intact endothelium, nitric oxide, production of hydrogen peroxide, and de novo protein synthesis. In transactivation assays in cultured HEK293 cells, THC-activated PPAR{gamma}, transiently expressed in combination with retinoid X receptor {alpha} and a luciferase reporter gene, in a concentration-dependent manner (100 nM-10 {mu}M). In vitro incubation with THC (1 or 10 {mu}M, 8 days) stimulated adipocyte differentiation in cultured 3T3L1 cells, a well-accepted property of PPAR{gamma} ligands. The present results provide strong evidence that THC is a PPAR{gamma} ligand, stimulation of which causes time-dependent vasorelaxation, implying some of the pleiotropic effects of cannabis may be mediated by nuclear receptors.

  1. Seasonal and interannual variability of the Mid-Holocene East Asian monsoon in coral δ18O records from the South China Sea

    Science.gov (United States)

    Sun, Donghuai; Gagan, Michael K.; Cheng, Hai; Scott-Gagan, Heather; Dykoski, Carolyn A.; Edwards, R. Lawrence; Su, Ruixia

    2005-08-01

    Understanding the full range of past monsoon variability, with reference to specific monsoon seasons, is essential to test coupled climate models and improve their predictive capabilities. We present a 54-year long, high-resolution skeletal oxygen isotope (δ18O) record extracted from a well-preserved, massive Porites sp. coral at Hainan Island, South China Sea, to investigate East Asian monsoon variability during summer and winter ∼4400 calendar yr ago. Analysis of modern coral δ18O confirms that Porites from Hainan Island are well positioned to record winter monsoon forcing of sea surface temperature (SST), as well as the influence of summer monsoon rainfall on sea surface salinity (SSS). The coral record for ∼4400 yr ago shows ∼9% amplification of the annual cycle of δ18O, in good agreement with coupled ocean-atmosphere models showing higher summer rainfall (lower coral δ18O) and cooler winter SSTs (higher coral δ18O) in response to greater Northern Hemisphere insolation seasonality during the Middle Holocene. Mean SSTs in the South China Sea during the Mid-Holocene were within 0.5 °C of modern values, yet the mean δ18O for the fossil coral is ∼0.6‰ higher than that for the modern coral, suggesting that the δ18O of surface seawater was higher by at least ∼0.5‰, relative to modern values. The 18O-enrichment is likely to be driven by greater advection of moisture towards the Asian landmass, enhanced monsoon wind-induced evaporation and vertical mixing, and/or invigorated advection of saltier 18O-enriched Pacific water into the relatively fresh South China Sea. The 18O-enrichment of the northern South China Sea ∼4400 yr ago contributes to mounting evidence for recent freshening of the tropical Western Pacific. Today, winter SST and summer SSS variability in the South China Sea reflect the interannual influence of ENSO and the biennial variability inherent to monsoon precipitation. Spectral analysis of winter SSTs ∼4400 yr ago reveals a

  2. Electrochemical zinc insertion into W18O49: Synthesis and characterization of new bronzes

    International Nuclear Information System (INIS)

    Martinez-de la Cruz, A.; Amador, U.; Rodriguez-Carvajal, J.; Garcia-Alvarado, F.

    2005-01-01

    Divalent zinc ions have been electrochemically inserted into W 18 O 49 , producing zinc bronzes. Under our experimental conditions, W 18 O 49 accepts zinc reversibly as a guest up to 0.9 ions per formula. The reaction seems to proceed through the formation of a solid solution in which the W-O framework of the parent oxide is maintained. The location of the Zn 2+ ions in the framework of W 18 O 49 has been determined by neutron diffraction on a chemically prepared sample having the composition Zn 0.34 W 18 O 49 . As a main result, we found that Zn prefers to insert in one of the four types of quadrangular tunnels. More precisely, it is displaced from the center to occupy a low coordination site. This result indicates that a significant covalent character exists in the Zn-O bond. - Graphical Abstract: The structure of Zn 0.36 W 18 O 49 projected along the b-axis

  3. Determination of sup 18 O concentrations in microsamples of biological fluids

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, D D [Australian Nuclear Science and Technology Organisation (ANSTO), Menai (Australia); Bradshaw, S D; Bradshaw, F J [University of Western Australia, Perth (Australia). Dept. of Zoology; Katsaros, A [Australian Inst. of Nuclear Science and Engineering (AINSE), Menai (Australia)

    1990-04-01

    The {sup 18}O(p, {alpha}){sup 15}N reaction has been developed for the analysis of microsamples of biological fluids containing {sup 18}O-enriched water. Samples as small as 50 {mu}l have been used. Well characterized Ta{sub 2}O{sub 5} targets were prepared from these fluids and irradiated with several hundred nA of protons from the 3 MV Van de Graaff at Lucas Heights. The broad (47 keV) 846 kV resonance in this reaction was used to measure {sup 18}O concentrations down to natural backgrounds (0.2 at.%) in a few minutes of accelerator running time. Concentrations of {sup 18}O from 0 to 5 at.% were measured in body fluids in small Australian lizards directly after doping with {sup 18}O-enriched water and then again after several days of roaming around in their natural desert environments. The changes in these levels were related to the metabolic rates of these animals. (orig.).

  4. Analysis of stable isotope ratios (δ18O and δ2H) in precipitation of the Verde River watershed, Arizona 2003 through 2014

    Science.gov (United States)

    Beisner, Kimberly R.; Paretti, Nicholas V.; Tucci, Rachel S.

    2016-04-25

    Stable isotope delta values18O and δ2H) of precipitation can vary with elevation, and quantification of the precipitation elevation gradient can be used to predict recharge elevation within a watershed. Precipitation samples were analyzed for stable isotope delta values between 2003 and 2014 from the Verde River watershed of north-central Arizona. Results indicate a significant decrease in summer isotopic values overtime at 3,100-, 4,100-, 6,100-, 7,100-, and 8,100-feet elevation. The updated local meteoric water line for the area is δ2H = 7.11 δ18O + 3.40. Equations to predict stable isotopic values based on elevation were updated from previous publications in Blasch and others (2006), Blasch and Bryson (2007), and Bryson and others (2007). New equations were separated for samples from the Camp Verde to Flagstaff transect and the Prescott to Chino Valley transect. For the Camp Verde to Flagstaff transect, the new equations for winter precipitation are δ18O = -0.0004z − 8.87 and δ2H = -0.0029z − 59.8 (where z represents elevation in feet) and the summer precipitation equations were not statistically significant. For the Prescott to Chino Valley transect, the new equations for summer precipitation are δ18O = -0.0005z − 3.22 and δ2H = -0.0022z − 27.9; the winter precipitation equations were not statistically significant and, notably, stable isotope values were similar across all elevations. Interpretation of elevation of recharge contributing to surface and groundwaters in the Verde River watershed using the updated equations for the Camp Verde to Flagstaff transect will give lower elevation values compared with interpretations presented in the previous studies. For waters in the Prescott and Chino Valley area, more information is needed to understand local controls on stable isotope values related to elevation.

  5. Environmental isotopes (N, S, C, O, D) to determine natural attenuation processes in nitrate contaminated waters: Example of Osona (NE Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Vitoria, Laura [Grup de Mineralogia Aplicada i Medi Ambient, Departament de Cristal.lografia, Mineralogia i Diposits Minerals, Facultat de Geologia, Universitat de Barcelona, Marti i Franques, s/n, 08028, Barcelona (Spain)], E-mail: lvitoria@ub.edu; Soler, Albert; Canals, Angels [Grup de Mineralogia Aplicada i Medi Ambient, Departament de Cristal.lografia, Mineralogia i Diposits Minerals, Facultat de Geologia, Universitat de Barcelona, Marti i Franques, s/n, 08028, Barcelona (Spain); Otero, Neus [Grup de Mineralogia Aplicada i Medi Ambient, Departament de Cristal.lografia, Mineralogia i Diposits Minerals, Facultat de Geologia, Universitat de Barcelona, Marti i Franques, s/n, 08028, Barcelona (Spain); Departament de Geologia Ambiental, Institut de Ciencies de la Terra ' Jaume Almera' , CSIC C/Lluis Sole i Sabaris s/n, Barcelona 08028 (Spain)

    2008-12-15

    Nitrate-contaminated groundwater from an aquifer in the Osona region (NE Spain) was chemically and isotopically ({delta}{sup 15}N{sub NO{sub 3}},{delta}{sup 18}O{sub NO{sub 3}},{delta}{sup 34}S{sub SO{sub 4}},{delta}{sup 18}O{sub SO{sub 4}}, {delta}D, {delta}{sup 18}O{sub H{sub 2}}{sub O} and {delta}{sup 13}C{sub DIC}) characterized. Diffuse- NO{sub 3}{sup -} contamination reached values of 366 mg/L. Nearly 75% of the 37 sampled sites had higher concentrations than the 50 mg/L in NO{sub 3}{sup -} limit for drinking water. To identify the source of pollution {delta}{sup 15}N{sub NO{sub 3}} and {delta}{sup 18}O{sub NO{sub 3}} were used with results, for most samples, in the range of pig manure NO{sub 3}{sup -}. Nitrification processes were evaluated by means of the {delta}{sup 18}O of NO{sub 3}{sup -} and water. Isotopic data suggested that natural attenuation of NO{sub 3}{sup -} was taking place. This process was confirmed using the {delta}{sup 18}O{sub NO{sub 3}} coupled with the NO{sub 3}{sup -}/Cl{sup -} ratio, avoiding the influence of continuous NO{sub 3}{sup -} inputs. A further insight on denitrification processes was obtained by analyzing the ions involved in denitrification reactions. Although the role of organic matter oxidation could neither be confirmed nor discarded, this approach showed a link between denitrification and pyrite oxidation. Therefore, in areas with no adequate infrastructure (e.g. multipiezometers), such as the one studied, this approach could be useful for implementing better water management.

  6. The systematics of the (18O,20Ne) reaction and its application to the determination of the mass excess of 122Cd

    International Nuclear Information System (INIS)

    Kruechten, B. van.

    1987-01-01

    The aim of the thesis should be the determination of the mass excess of the neutron-deficient nucleus 122 Cd with the ( 18 O, 20 Ne) reaction proved for light target nuclei (A lab ≤ 15 0 ) lay below the detection limit of 1 μb/sr it was first necessary to determine optimum kinematical conditions for the study of the reaction 124 Sn( 18 O, 20 Ne). For this purpose systematic studies of the angular distributions of the ( 18 O, 20 Ne) reaction on target nuclei with mass numbers between 28 ( 28 Si) and 208 ( 208 Pb) were performed at beam energies of 82, 102, 141, and 189 MeV. The evaluation of these measurements gave first information on the dependences of the cross sections on energy, Q-value, target mass, and angle. For the 124 Sn( 18 O, 20 Ne) 122 Cd reaction a maximum cross section of about 1 μb/sr at a beam energy 30 MeV above the Coulomb threshold (100 MeV) and a laboratory angle of 40 0 could be expected. In a new experiment this prediction could be verified. The analysis of the measured spectra yielded a Q-value for the 124 Sn( 18 O, 20 Ne) 122 Cd reaction of 0.1 ± 0.44 MeV. The mass excess of -82.08 ± 0.44 MeV calculated from this for 122 Cd is by 1.5 MeV more positive than the prediction of the Wapstra table. (orig./HSI) [de

  7. 18O isotopic characterisation of non-point source contributed heavy metals (Zn and Cu) contamination of groundwater

    International Nuclear Information System (INIS)

    Datta, P.S.; Manjaiah, K.M.; Tyagi, S.K.

    1999-01-01

    In many urbanised areas, fast depletion and severe degradation of the of groundwater resource with contaminants such as nitrate, fluoride, and heavy metals is a common phenomenon, resulting in zonal disparity in fresh water availability. Therefore, for protection of groundwater from pollution and depletion, it is a matter of concern for the planners and decision makers to clearly characterise the sources of contamination and to search for an alternative approach for groundwater development and management. In this context, a new approach is presented here, based on monitoring of 18 O stable isotopic and heavy metals composition of groundwater, to clearly characterise non-point source contributed heavy metals pollution of groundwater in northern parts of Delhi area. In the investigated area, the Cu content in the groundwater ranges from 3-41 μg/l and Zn content ranges from 5-182 μg/l, showing considerable variation from location to location as well as within the small parts of a location. Wide variation in the 18 O stable isotope content of groundwater (δ value of -5.7 per mille to -8.5 per mille) is due to significant variation in the δ 18 O-contents of rainfall with space and time, as well as intensity and distribution of rainfall. Enrichment in 18 O composition with increasing Cu and Zn levels in groundwater suggest that infiltration of rain water, irrigation water and surface run-off water from the surrounding farm lands, along with agrochemicals and other salts present in the soil, to be the main processes causing groundwater contamination. The concentration of Cu and Zn in groundwater vary spatially, due to different degrees of evaporation/recharge, amounts of fertiliser applied and wastes disposed, adsorption/dispersion of species in the soils and lateral mixing of groundwater. Two opposite mechanisms adsorption and redistribution of infiltrating water along with Zn and Cu species in the soil zone are likely to affect the movement of the Zn and Cu species

  8. {sup 18}O, {sup 2}H and {sup 3}H isotopic composition of precipitation and shallow groundwater in Olkiluoto

    Energy Technology Data Exchange (ETDEWEB)

    Hendriksson, N. [Geological Survey of Finland, Espoo (Finland); Karhu, J.; Niinikoski, P. [Univ. of Helsinki (Finland)

    2014-12-15

    The isotopic composition of oxygen and hydrogen in local precipitation is a key parameter in the modelling of local water circulation. This study was initiated in order to provide systematic monthly records of the isotope content of atmospheric precipitation in the Olkiluoto area and to establish the relation between local rainfall and newly formed groundwater. During January 2005 - December 2012, a total of 85 cumulative monthly rainfall samples and 68 shallow groundwater samples were collected and the isotopic composition of oxygen and hydrogen was recorded for all those samples. Tritium values are available for 79 precipitation and 65 groundwater samples. Based on the 8-year monitoring, the long-term weighted annual mean isotope values of precipitation and the mean values of shallow groundwater are -11.59 per mille and -11.27 per mille for δ{sup 18}O, - 82.3 per mille and -80.3 per mille for δ{sup 2}H and 9.8 and 9.1 TU for tritium, respectively. Based on these data, the mean stable isotope ratios of groundwater represent the long-term mean annual isotopic composition of local precipitation. The precipitation data were used to establish the local meteoric water line (LMWL) for the Olkiluoto area. The line is formulated as: δ{sup 2}H = 7.45 star δ{sup 18}O + 3.82. The isotope time series reveal a change in time. The increasing trend for the δ{sup 18}O and δ{sup 2}H values may be related to climatic variability while the gradual decline observed in the {sup 3}H data is attributed to the still continuing decrease in atmospheric {sup 3}H activity in the northern hemisphere. The systematic seasonal and long-term tritium trends suggest that any potential ground-level tritium release from the Olkiluoto nuclear power plants is insignificant. The d-excess values of Olkiluoto precipitation during the summer period indicated that a notable amount of re-cycled Baltic Sea water may have contributed to precipitation in the Finnish southern coast. Preliminary estimates

  9. Hydrological cycle research by D & 18 O tracing in small watershed in the loess hilly region

    Directory of Open Access Journals (Sweden)

    Xu Xuexuan

    2013-12-01

    Full Text Available The objective of this study was to determine the mechanisms of the hydrologic cycle in the loess area in China. Sixty eight water samples from precipitation, soil water of the 0 – 4 m layer, surface water in the valley, ground water (spring and well were collected and the Deuterium (D and Oxygen – 18 (O of these water samples were analyzed to interpret the relationship among those waters in the watershed in the loess hilly region during 2005 – 2009. The results show that: the D & 18O of precipitation in Yangou was consistent with that of Xi'an, apparently the north migration of water vapor in Xi'an; according to the correlations among the differential waters in D & 18 O, confirmed that precipitation recharge could account for most of the sources of valley flow, with part of the recharge water going to soil water recharge. The D & 18O of groundwater were very close to that of precipitation, likely the soil preferential flow was dominant in groundwater recharge although the infiltration had a certain lag. Under the influence of rainfall and evaporation, the response of the soil moisture profile, and its D & 18O profile were different. The soil moisture had the strong influenced layer in the 0 60 cm range, a weak impacted layer in 60 160 cm, and a stable layer below 160 cm. It was shown that the soil evaporation depth could be up to 160 cm because the D & 18O changed in that depth. The study could increase our understanding of the magnitude and pattern of the hydrologic cycle, which should improve water resources management in the watershed scale.

  10. Nuclear microanalysis of 16O and 18O in near-surface regions of solids. Applications

    International Nuclear Information System (INIS)

    Amsel, G.

    The best suited nuclear technique for 18 O analysis is the direct observation of nuclear reactions. Here, instead of measuring an induced radioactivity, one observes the particles emitted as a result of the O 18 (p,α)N 15 reaction. The α particles which are produced may be detected with surface barrier semiconductor detectors; they present unit detection efficiency and allow one to realize large solid angles of detection, while their energy resolution is excellent. For getting O 18 /O 16 ratios, 16 O must also be measured. This is achieved in a similar way, using the O 16 (d,p) 17 O reaction [fr

  11. Excitation of the lowest 1- state in 18O by scattering from 16O

    International Nuclear Information System (INIS)

    Carter, J.; Sellschop, J.P.F.; Clarkson, R.G.; Hnizdo, V.; Osterfeld, F.; Frahn, W.E.; Richter, A.

    1981-01-01

    The 1 - (4.45 MeV) state in 18 O, together with the 2 + (1.98 MeV) and 3 - (5.09 MeV) states, were excited by inelastic scattering from 16 O at E(lab)=35 MeV. In an attempt to understand the 1 - excitation, various macroscopic models, including a ralationship derived recently by Frahn, were considered. However, this excitation was found to be best explained by a microscopic description. A comparison is made with inelastic α-scattering from 18 O [af

  12. Inelastic scattering of polarized protons and nuclear deformation in 16O, 18O

    International Nuclear Information System (INIS)

    de Swiniarski, R.; Pham, D.L.

    1984-01-01

    Many data concerning inelastic scattering of polarized protons at intermediate energy are now available. We have analyzed some of these data coming from LAMPF at 800 MeV for 16 O (6) and 18 O (7) in order to further study nuclear deformations for these light nuclei. Analyzing powers (A(theta)) and cross-sections ((σ/theta)) for elastic and inelastic scattering of 800 MeV polarized protons from 16 O and 18 O have been analyzed in the coupled-channels (CC) collective model using the code ECIS from Raynal

  13. Can tree-ring isotopes (δ18O and δ13C) improve our understanding of hydroclimate variability in the Columbia River Basin?

    Science.gov (United States)

    Csank, A. Z.; Wise, E.; McAfee, S. A.

    2015-12-01

    The trajectory of incoming storms from the Pacific Ocean has a strong impact on hydroclimate in the Pacific Northwest. Shifts between zonal and meridional flow are a key influence on drought and pluvial regimes in both the PNW and the western United States as a whole. Circulation-dependent variability in the isotopic composition of precipitation can be recorded and potentially reconstructed using δ18O records derived from tree-rings. Here we present isotopic records of δ18O and δ13C from ponderosa pine (Pinus ponderosa) for the period 1950-2013 from six sites located in the lee of the Cascades in eastern Washington. Because of the orientation of the Cascades, zonal flow will result in an intensified rain shadow whereas meridional flow allows moisture to penetrate at a lower elevation leading to a lower rainout effect. This means zonal flow results in drier conditions in eastern Washington and the converse for meridional flow. We hypothesized that more depleted precipitation δ18O values will occur with periods of more zonal flow across the PNW and will be recorded by trees at our sites. Results show a strong relationship between our δ18O chronologies and winter precipitation (R = -0.50; p<0.001). δ13C chronologies from the same trees showed a relationship to prior fall/winter (pOct-pDec) precipitation (R = -0.46; p<0.005) suggesting a possible link to antecedent moisture conditions. With a focus on years with clear zonal and meridional flow regimes, we regressed the tree-ring δ18O anomaly against the instrumental record of total precipitation and compared the residual series to records of storm track for the period 1978-2008, and we found a detectable signal where the most depleted δ18O was generally associated with zonal flow and the most enriched δ18O with meridional flow. However, there are still some years where the relationship is unclear. Further work is aimed at understanding these anomalous years and extending our record beyond the instrumental

  14. USGS48 Puerto Rico precipitation - A new isotopic reference material for δ2H and δ18O measurements of water

    Science.gov (United States)

    Qi, Haiping; Coplen, Tyler B.; Tarbox, Lauren V.; Lorenz, Jennifer M.; Scholl, Martha A.

    2014-01-01

    A new secondary isotopic reference material has been prepared from Puerto Rico precipitation, which was filtered, homogenised, loaded into glass ampoules, sealed with a torch, autoclaved to eliminate biological activity, and calibrated by dual-inlet isotope-ratio mass spectrometry. This isotopic reference material, designated as USGS48, is intended to be one of two isotopic reference waters for daily normalisation of stable hydrogen (δ2H) and stable oxygen (δ18O) isotopic analysis of water with a mass spectrometer or a laser absorption spectrometer. The δ2H and δ18O values of this reference water are−2.0±0.4 and−2.224±0.012 ‰, respectively, relative to Vienna Standard Mean Ocean Water on scales normalised such that the δ2H and δ18O values of Standard Light Antarctic Precipitation reference water are−428 and−55.5 ‰, respectively. Each uncertainty is an estimated expanded uncertainty (U=2uc) about the reference value that provides an interval that has about a 95 % probability of encompassing the true value. This isotopic reference water is available by the case of 144 glass ampoules containing 5 mL of water in each ampoule.

  15. Doubly labeled water (3HH18O) method: a guide to its use

    International Nuclear Information System (INIS)

    Nagy, K.A.

    1983-06-01

    The doubly labelled water method for measuring CO 2 production and water flux rates is used in studies of energy and material balance in animals living in their natural habitats. This report presents guidelines for the use of this method, including preparation of materials, field and laboratory procedures, and tritium and 18 O analysis techniques

  16. W18O49 nanowires assembled on carbon felt for application to supercapacitors

    Science.gov (United States)

    Jung, Jinjoo; Kim, Do Hyung

    2018-03-01

    For supercapacitor applications, W18O49 nanowires have been extensively grown on graphitic carbon felt using a facile solvothermal method. The diameter and length of the nanowires are about 7 and 300 nm, respectively. The nanowires consist of monoclinic W18O49 grown along the [010] direction, as shown by TEM and XRD analyses. The W18O49 nanowires, assembled on carbon felt, exhibit a high capacity of 588.33 F/g at a current density of 1 A/g together with an excellent cycle performance, and a low internal resistance during the electrochemical tests. This outstanding performance may originate from the three-dimensional porous nanostructure of these W18O49 nanowires, which leads to a reduction in the resistance and fast reaction kinetics due to the high specific surface area and electrolyte accessibility. Furthermore, sufficient oxygen deficiencies of the substoichiometric tungsten oxide can also contribute to the electrochemical activity, which can be confirmed by comparison of CV and EIS data with WO3 nanowires.

  17. Synthesis and atmospheric pressure field emission operation of W18O49 nanowires

    NARCIS (Netherlands)

    Agiral, A.; Gardeniers, Johannes G.E.

    2008-01-01

    Tungsten oxide W18O49 nanorods with diameters of 15−20 nm were grown on tungsten thin films exposed to ethene and nitrogen at 700 °C at atmospheric pressure. It was found that tungsten carbide formation enhances nucleation and growth of nanorods. Atmospheric pressure field emission measurements in

  18. {sup 13}CO/C{sup 18}O Gradients across the Disks of Nearby Spiral Galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Jiménez-Donaire, María J.; Cormier, Diane; Bigiel, Frank [Institut für theoretische Astrophysik, Zentrum für Astronomie der Universität Heidelberg, Albert-Ueberle Str. 2, D-69120 Heidelberg (Germany); Leroy, Adam K.; Gallagher, Molly [Department of Astronomy, The Ohio State University, 140 W 18th St, Columbus, OH 43210 (United States); Krumholz, Mark R. [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Usero, Antonio [Observatorio Astronómico Nacional, Alfonso XII 3, E-28014, Madrid (Spain); Hughes, Annie [CNRS, IRAP, 9 Av. colonel Roche, BP 44346, F-31028 Toulouse cedex 4 (France); Kramer, Carsten [Instituto de Astrofísica de Andalucía IAA-CSIC, Glorieta de la Astronomía s/n, E-18008, Granada (Spain); Meier, David [Department of Physics, New Mexico Institute of Mining and Technology, 801 Leroy Pl, Soccoro, NM 87801 (United States); Murphy, Eric [National Radio Astronomy Observatory, 520 Edgemont Rd, Charlottesville, VA 22903 (United States); Pety, Jérôme; Schuster, Karl [Institut de Radioastronomie Millimétrique (IRAM), 300 Rue de la Piscine, F-38406 Saint Martin d’Hères (France); Schinnerer, Eva; Sliwa, Kazimierz; Tomicic, Neven [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Schruba, Andreas, E-mail: m.jimenez@zah.uni-heidelberg.de [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching (Germany)

    2017-02-20

    We use the IRAM Large Program EMPIRE and new high-resolution ALMA data to measure {sup 13}CO(1-0)/C{sup 18}O(1-0) intensity ratios across nine nearby spiral galaxies. These isotopologues of {sup 12}CO are typically optically thin across most of the area in galaxy disks, and this ratio allows us to gauge their relative abundance due to chemistry or stellar nucleosynthesis effects. Resolved {sup 13}CO/C{sup 18}O gradients across normal galaxies have been rare due to the faintness of these lines. We find a mean {sup 13}CO/C{sup 18}O ratio of 6.0 ± 0.9 for the central regions of our galaxies. This agrees well with results in the Milky Way, but differs from results for starburst galaxies (3.4 ± 0.9) and ultraluminous infrared galaxies (1.1 ± 0.4). In our sample, the {sup 13}CO/C{sup 18}O ratio consistently increases with increasing galactocentric radius and decreases with increasing star formation rate surface density. These trends could be explained if the isotopic abundances are altered by fractionation; the sense of the trends also agrees with those expected for carbon and oxygen isotopic abundance variations due to selective enrichment by massive stars.

  19. 18O+58Ni reaction at 35 MeV/nucleon

    International Nuclear Information System (INIS)

    Etchegoyen, M.C.; Etchegoyen, A.; Macchiavelli, A.O.

    1990-01-01

    Momentum and angular distributions of projectile like fragments were measured in the vicinity of the grazing angle for the reaction 18 O+ 58 Ni at 35 MeV/nucleon. Mass and charge identification was achieved with the use of a magnetic spectrometer. Momentum spectra were analyzed assuming fragmentation of the projectile. (orig.)

  20. Impact of convective activity on precipitation δ18O in isotope-enabled models

    Science.gov (United States)

    Hu, J.; Emile-Geay, J.; Dee, S.

    2017-12-01

    The ^18O signal preserved in paleo-archives (e.g. speleothem, tree ring cellulose, ice cores) is widely used to reconstruct precipitation or temperature. In the tropics, the inverse relationship between precipitation ^18O and rainfall amount, namely "amount effect" [Dansgaard, Tellus, 1964], is often used to interpret precipitation ^18O. However, recent studies have shown that precipitation ^18O is also influenced by precipitation type [Kurita et al, JGR, 2009; Moerman et al, EPSL, 2013], and recent observations indicate that it is negatively correlated with the fraction of precipitation associated with stratiform clouds [Aggarwal et al, Nature Geosci, 2016]. It is thus important to determine to what extent isotope-enabled climate models can reproduce these relationships. Here we do so using output from LMDZ, CAM2, and isoGSM from the Stable Water Isotope Intercomparison Group, Phase 2 (SWING2) project and results of SPEEDY-IER [Dee et al, JGR, 2015] from an AMIP-style experiment. The results show that these models simulate the "amount effect" well in the tropics, and the relationship between precipitation ^18O and precipitation is reversed in many places in mid-latitudes, in accordance with observations [Bowen, JGR, 2008]. Also, these models can all reproduce the negative correlation between monthly precipitation ^18O and stratiform precipitation proportion in mid-latitude (30°N-50°N; 50°S-30°S), but in the tropics (30°S-30°N), models show a positive correlation instead. The reason for this bias will be investigated within idealized experiments with SPEEDY-IER. The correct simulations of the impact of convective activity on precipitation ^18O in isotope-enabled models will improve our interpretation of paleoclimate proxies with respect to hydroclimate variability. P. K. Aggarwal et al. (2016), Nature Geosci., 9, 624-629, doi:10.1038/ngeo2739. G. J. Bowen. (2008), J. Geophys. Res., 113, D05113, doi:10.1029/2007JD009295. W. Dansgaard (1964), Tellus, 16(4), 436

  1. The co-evolution of seawater δ18O and δD

    Science.gov (United States)

    Pope, E. C.

    2017-12-01

    The δ18O of marine carbonate and silica precipitates has increased by 15‰ over the last ca. 3.5 billion years. Whether this shift reflects a parallel increase in oxygen isotope compositions of seawater with time, Precambrian atmospheric temperatures >55°C, or complete alteration of ancient samples during diagenesis, remains controversial despite nearly a half-century of debate. Early mass balance models of the modern ocean system suggested near constant δ18OSEAWATER over time due to the buffering capacity of fresh oceanic crust. However, fluxes controlling 18O sources and sinks to the ocean (high-temperature alteration of the seafloor, and low-temperature weathering of continental and ocean crust, respectively) have not remained fixed throughout Earth history. I adapted published mass balance models for δ18OSEAWATER to evaluate how continental growth, the subaerial emergence of continents, and decreasing mantle temperature affect the magnitude of 18O sources and sinks, and thus the evolution of seawater δ18O since the early Archean. These factors also affect the δD of seawater, which is controlled by the flux of water between mantle, crustal and glacial reservoirs, such that its evolution can be used as an independent constraint on the magnitude that these variables have had on δ18O evolution. The models indicate that a key parameter controlling δ18OSEAWATER is the flux of water between the mantle and free water of the exosphere. Recent geophysical models suggest that the capacity for subducting slabs to sequester water into the deep ocean has increased as the mantle has cooled. Hydrous minerals in subducted oceanic crust have a net δ18O lower than seawater. Incomplete recycling of water from these phases in subduction zones results in progressive removal of 16O from the ocean and thus can explain a significant portion of the increase in δ18O recorded in the marine sediment record. However, mass balance constraints on the global hydrogen budget limits

  2. 99 Tc NMR determination of the oxygen isotope content in 18 O-enriched water.

    Science.gov (United States)

    Tarasov, Valerii P; Kirakosyan, Gayana А; German, Konstantin E

    2018-03-01

    99 Tc NMR has been suggested as an original method of evaluating the content of oxygen isotopes in oxygen-18-enriched water, a precursor for the production of radioisotope fluorine-18 used in positron emission tomography. To this end, solutions of NH 4 TcO 4 or NaTcO 4 (up to 0.28 mol/L) with natural abundance of oxygen isotopes in virgin or recycled 18 O-enriched water have been studied by 99 Tc NMR. The method is based on 16 O/ 17 O/ 18 O intrinsic isotope effects in the 99 Tc NMR chemical shifts, and the statistical distribution of oxygen isotopes in the coordination sphere of TcO 4 - and makes it possible to quantify the composition of enriched water by measuring the relative intensities of the 99 Tc NMR signals of the Tc 16 O 4-n 18 O n - isotopologues. Because the oxygen exchange between TcO 4 - and enriched water in neutral and alkaline solutions is characterized by slow kinetics, gaseous HCl was bubbled through a solution for a few seconds to achieve the equilibrium distribution of oxygen isotopes in the Tc coordination sphere without distortion of the oxygen composition of the water. Pertechnetate ion was selected as a probe due to its high stability in solutions and the significant 99 Tc NMR shift induced by a single 16 O→ 18 O substitution (-0.43 ± 0.01 ppm) in TcO 4 - and spin coupling constant 1 J( 99 Tc- 17 O) (131.46 Hz) favourable for the observation of individual signals of Tc 16 O 4-n 18 O n - isotopologues. Copyright © 2017 John Wiley & Sons, Ltd.

  3. Determination of 18O by prompt nuclear reaction analysis: application for measurement of microsamples

    International Nuclear Information System (INIS)

    Bradshaw, S.D.; Cohen, D.; Katsaros, A.; Tom, J.; Owen, I.J.

    1987-01-01

    A method is described for the routine determination of 18 O concentrations in microsamples of biological fluids. The method utilizes the prompt nuclear reaction 18 O(p,α 0 ) 15 N, and 846-keV protons from a 3-MeV Van de Graaff Accelerator are focused on ∼2,000-Angstroem-thick Ta 2 O 5 targets prepared by anodic oxidation from 50-μl samples of water distilled from blood or other biological fluids. The broad cross section of the resonance peak for this nuclear reaction (47 keV) ensures high yields, especially at small reaction angles, and the high-energy α particles produced by the reaction (4 MeV) are readily separated from scattered protons by the use of an aluminized Mylar foil of suitable thickness. Background levels of 18 O (0.204 atom%) can be detected with run times of ∼5-8 min, and the sensitivity of the method is of the order of 0.05 atom%. Experimental error due to sample preparation was found to be 1.7%, and counting errors were close to theoretical limits so that total error was of the order of 2.5%. Duplicate samples were analyzed by use of the 18 O(p,α 0 ) 15 N reaction at Lucas Heights, Australia and the 18 O(p,n) 18 F reaction at the University of California, Los Angeles, and the agreement was excellent (y = 1.0123x - 0.0123, r = 0.991, P < 0.001). The theoretical limitations and the general applicability of the method in biological studies designed to estimate the rate of metabolism of free-ranging animals are also discussed. 24 refs., 2 tabs., 7 figs

  4. The Potential of Ikaite to Record the Oceanic Evolution of ?18O

    Science.gov (United States)

    Rickaby, R. E.; Shaw, S.; Bennitt, G.; Kennedy, H. A.; Lennie, A.

    2005-12-01

    Despite the importance of sea level for understanding past climates, paleoceanographers struggle to construct a continuous and definitive record of oceanic δ18O over millennial timescales. Here, we explore the possibility that ikaite, a hydrated form of calcium carbonate which forms monoclinic crystals made of CaCO3.6H2O units linked together by hydrogen bonds, may record the δ18O of the water from which it precipitates. Naturally occurring samples of ikaite have been found in the Ikka Fjord in Greenland where the crystals grow into huge chimneys around cold water springs at a temperature of 3°C, and ephemeral occurrences are also noted in alkaline lakes such as Mono Lake, California. The stability field of ikaite suggests that it should not exist at normal ocean temperatures and pressures. Nonetheless, the presence of ikaite has been recognised increasingly in areas such as the Bransfield Strait, Sea of Okhotsk, the Laptev Sea and the Lower Zaire Deep Sea fan, where sediments rich in organic carbon are characterised by high alkalinity and the presence of sulphate or phosphate which inhibits calcite precipitation. Whilst the presence and isotopic composition of glendonite, a pseudomorph of ikaite has been used as a key environmental indicator in the geological record, ikaite from recent ocean sediments has never been preserved for geochemical analysis. We have performed a series of laboratory growth experiments of ikaite under controlled conditions of alkalinity and temperature, from waters with a range of δ18O. Our results demonstrate that, in accordance with theory, the crystal bound waters in ikaite are isotopically heavier than the ambient water. Further a simple linear relationship with a non-zero intercept exists between the δ18O of the hydration waters of ikaite, and the waters from which the crystal precipitated. These data provide a firm foundation for application of this methodology to reconstruct oceanic δ18O from ikaite in Pleistocene sediments.

  5. Determination of the δ15N and δ18O of nitrate in water; RSIL lab code 2900

    Science.gov (United States)

    Coplen, Tyler B.; Qi, Haiping; Revesz, Kinga; Casciotti, Karen; Hannon, Janet E.

    2007-01-01

    The purpose of the Reston Stable Isotope Laboratory (RSIL) lab code 2900 is to determine the δ15N and δ18O of nitrate (NO3-) in water. The δ15N and δ18O of the dissolved NO3- are analyzed by converting the NO3- to nitrous oxide (N2O), which serves as the analyte for mass spectrometry. A culture of denitrifying bacteria is used in the enzymatic conversion of the NO3- to N2O, which follows the pathway shown in equation 1: NO3- → NO2- → NO → 1/2 N2O (1) Because the bacteria Pseudomonas aureofaciens lack N2O reductive activity, the reaction stops at N2O, unlike the typical denitrification reaction that goes to N2. After several hours, the conversion is complete, and the N2O is extracted from the vial, separated from volatile organic vapor and water vapor by an automated -65 °C isopropanol-slush trap, a Nafion drier, a CO2 and water removal unit (Costech #021020 carbon dioxide absorbent with Mg(ClO4)2), and trapped in a small-volume trap immersed in liquid nitrogen with a modified Finnigan MAT (now Thermo Scientific) GasBench 2 introduction system. After the N2O is released, it is further purified by gas chromatography before introduction to the isotope-ratio mass spectrometer (IRMS). The IRMS is a Thermo Scientific Delta V Plus continuous flow IRMS (CF-IRMS). It has a universal triple collector, consisting of two wide cups with a narrow cup in the middle; it is capable of simultaneously measuring mass/charge (m/z) of the N2O molecule 44, 45, and 46. The ion beams from these m/z values are as follows: m/z = 44 = N2O = 14N14N16O; m/z = 45 = N2O = 14N15N16O or 14N14N17O; m/z = 46 = N2O = 14N14N18O. The 17O contributions to the m/z 44 and m/z 45 ion beams are accounted for before δ15N values are reported.

  6. Determination of the δ15N and δ18O of nitrate in solids; RSIL lab code 2897

    Science.gov (United States)

    Coplen, Tyler B.; Qi, Haiping; Revesz, Kinga; Casciotti, Karen; Hannon, Janet E.

    2007-01-01

    The purpose of the Reston Stable Isotope Laboratory (RSIL) lab code 2897 is to determine the δ15N and δ18O of nitrate (NO3-) in solids. The NO3- fraction of the nitrogen species is dissolved by water (called leaching) and can be analyzed by the bacterial method covered in RSIL lab code 2900. After leaching, the δ15N and δ18O of the dissolved NO3- is analyzed by conversion of the NO3- to nitrous oxide (N2O), which serves as the analyte for mass spectrometry. A culture of denitrifying bacteria is used in the enzymatic conversion of NO3- to N2O, which follows the pathway shown in equation 1: NO3- → NO2- → NO → 1/2 N2O (1) Because the bacteria Pseudomonas aureofaciens lack N2O reductive activity, the reaction stops at N2O, unlike the typical denitrification reaction that goes to N2. After several hours, the conversion is complete, and the N2O is extracted from the vial, separated from volatile organic vapor and water vapor by an automated -65 °C isopropanol-slush trap, a Nafion drier, a CO2 and water removal unit (Costech #021020 carbon dioxide absorbent with Mg(ClO4)2), and trapped in a small-volume trap immersed in liquid nitrogen with a modified Finnigan MAT (now Thermo Scientific) GasBench 2 introduction system. After the N2O is released, it is further purified by gas chromatography before introduction to the isotope-ratio mass spectrometer (IRMS). The IRMS is a Thermo Scientific Delta V Plus continuous flow IRMS (CF-IRMS). It has a universal triple collector, consisting of two wide cups with a narrow cup in the middle; it is capable of simultaneously measuring mass/charge (m/z) of the N2O molecule 44, 45, and 46. The ion beams from these m/z values are as follows: m/z = 44 = N2O = 14N14N16O; m/z = 45 = N2O = 14N15N16O or 14N14N17O; m/z = 46 = N2O = 14N14N18O. The 17O contributions to the m/z 44 and m/z 45 ion beams are accounted for before δ15N values are reported.

  7. Tequila authenticity assessment by headspace SPME-HRGC-IRMS analysis of 13C/12C and 18O/16O ratios of ethanol.

    Science.gov (United States)

    Aguilar-Cisneros, Blanca O; López, Mercedes G; Richling, Elke; Heckel, Frank; Schreier, Peter

    2002-12-18

    By use of headspace SPME sampling and a PLOT column, on-line capillary gas chromatography-isotope ratio mass spectrometry was employed in the combustion (C) and the pyrolysis (P) modes (HRGC-C/P-IRMS) to determine the delta(13)C(VPDB) and delta(18)O(VSMOW) values of ethanol in authentic (n = 14) and commercial tequila samples (n = 15) as well as a number of other spirits (n = 23). Whereas with delta(13)C(VPDB) values ranging from -12.1 to -13.2 per thousand and from -12.5 to -14.8 per thousand similar variations were found for 100% agave and mixed tequilas, respectively, the delta(18)O(VSMOW) data differed slightly within these categories: ranges from +22.1 to +22.8 per thousand and +20.8 to +21.7 per thousand were determined for both the authentic 100% agave and mixed products, respectively. The data recorded for commercial tequilas were less homogeneous; delta(13)C(VPDB) data from -10.6 to -13.9 per thousand and delta(18)O(VSMOW) values from +15.5 to +22.7 per thousand were determined in tequilas of both categories. Owing to overlapping data, attempts to differentiate between white, rested, and aged tequilas within each of the two categories failed. In addition, discrimination of tequila samples from other spirits by means of delta(13)C(VPDB) and delta(18)O(VSMOW) data of ethanol was restricted to the products originating from C(3) as well as C(4)/CAM raw materials.

  8. Laser Spectroscopy Monitoring of 13C18O16O and 12C17O16O of Atmospheric Carbon Dioxide

    Science.gov (United States)

    Shorter, J. H.; Nelson, D. D.; Ono, S.; McManus, J. B.; Zahniser, M. S.

    2017-12-01

    One of the main challenges to making accurate predictions of future changes in CO2 concentration is the capability to determine what fraction of human produced CO2 remains in the atmosphere. We present our progress in the application of Tunable Infrared Laser Direct Absorption Spectroscopy (TILDAS) to the measurement of the primary clumped (13C18O16O) as well as 17O (12C17O16O) isotopologues of atmospheric CO2, as a tracer of its sources and sinks. We expect unique isotopologue signals in CO2 from high-temperature combustion sources, plants, soils, and air-sea exchange processes. High sampling frequency (a few minutes for each sample vs. reference cycle) achieved by a TILDAS instrument is expected to enable us to document local heterogeneous sources and temporal variations. The TILDAS is equipped with a newly developed 400-meter absorption cell. We designed a dual pressure measurement technique in which the clumped isotopologue, 13C18O16O, and 13C16O16O are first measured at 30 torr cell pressure. This is followed by measurement of 12C17O16O, 12C18O16O and 12C16O16O at lower ( 5 torr) cell pressure. Isotopologue ratios are compared between reference and sample gases. Preliminary tests demonstrated a precision approaching 0.03 ‰ for the ratio 13C18O16O/13C16O16O and 0.08‰ for Δ13C18O16O value (1σ repeatability for 4 min sample vs. reference cycle). Sample size for a single analysis is approximately 100 mL of air (1.6μmol of CO2). Given the previously observed range of variations for Δ13C18O16O and Δ17O values as large as 0.6 to 0.3 ‰, respectively, TILDAS offers a novel approach for real time monitoring of atmospheric CO2 isotopologues. It was found that achieving better than 0.1‰ requires careful matching of CO2 mixing ratios between reference and sample air. A primary cause of pressure and mixing ratio dependence is inaccurate baseline fitting (analogous to abundance sensitivity or pressure baseline for IRMS). Given that mixing ratios of atmospheric

  9. Geochemical disparity of d13C and d18O in gryphaeidae oysters

    Science.gov (United States)

    Videt, B.; Bentaleb, I.; Néraudeau, D.

    2003-04-01

    Several geochemical analyses of stable isotopes have been made on the group of the oysters in the past. However the majority of the studies are often focused on the sole family of Ostreidea which constituted a minority in the oyster diversity during Mesozoic times. The purpose of this study is to improve knowledge of the modality of isotopic signal record in the group of Gryphaeidae, notable for its abundance and its omnipresence within the Mesozoic outcropts. In this way, a high resolution isotopic study was carried out on the genera Pycnodonte and Ceratostreon. Each microgrowth increment was sampled with the aim of following the variations of the isotopic ratios during ontogenis. It was then possible to reveal a cyclicity of the signal for these two genera which is ascribable to a saisonnality. With end to test the validity of our results, the studies were lead on individuals coming from two lineage of Cenomanian and Campanian Gryphaeidae. For each period the individuals were obviously collected in the same thin layer, and thus subjected to same the environmental conditions during their life. The respective signal of Ceratostreon flabellatum and Pycnodonte biauriculata of upper Cenomanian are compared and then respectively confronted with Ceratostreon pliciferum and Pycnodonte vesicularis of final Campanian. Thus it is possible to observe a systematic shift of about of 1 per mil for δ13C -relative to PDB- between the two genera. More surprising, range of values of δ18O is strongly exaggerated for Ceratostreon genus. Also, these values could not be directly translated into term of palaeotemperature. An observation of the isotopic curves reveals a progressive shift of about of +0.5 ppm during ontogenesis of the two Ceratostreon species. The previous works showsthat the fossil oysters have a good aptitude to record fluctuation of the environmental conditions. But this study shows too that the previous results are not generalizable. At beyond this study warns

  10. Tritium in [18O]water containing [18F]fluoride for [18F]FDG synthesis

    International Nuclear Information System (INIS)

    Ito, Shigeki; Saze, Takuya; Sakane, Hitoshi; Ito, Satoshi; Ito, Shinichi; Nishizawa, Kunihide

    2004-01-01

    The presence of tritium in enriched [ 18 O]water irradiated with 9.6 MeV protons used to produce [ 18 F]fluoride by the 18 O(p, n) 18 F reaction was inferred from the cross sections and threshold energies of the 18 O(p, t) 16 O reaction, and the existence of tritium was confirmed experimentally. Tritium was also detected in both [ 18 O]water recovered for recycling and waste acetonitrile solutions. The purified [ 18 F]FDG was not contaminated with 3 H. The amount of 3 H discharged into the air was far less than the International Basic Safety Standard Level

  11. Evidence for a universal pathway of abscisic acid biosynthesis in higher plants from sup 18 O incorporation patterns

    Energy Technology Data Exchange (ETDEWEB)

    Zeevaart, J.A.D.; Heath, T.G.; Gage, D.A. (Michigan State University, East Lansing (USA))

    1989-12-01

    Previous labeling studies of abscisic acid (ABA) with {sup 18}O{sub 2} have been mainly conducted with water-stressed leaves. In this study, {sup 18}O incorporation into ABA of stressed leaves of various species was compared with {sup 18}O labeling of ABA of turgid leaves and of fruit tissue in different stages of ripening. In stressed leaves of all six species investigated, avocado (Persea americana), barley (Hordeum vulgare), bean (Phaseolus vulgaris), cocklebur (Xanthium strumarium), spinach (Spinacia oleracea), and tobacco (Nicotiana tabacum), {sup 18}O was most abundant in the carboxyl group, whereas incorporation of a second and third {sup 18}O in the oxygen atoms on the ring of ABA was much less prominent after 24 h in {sup 18}O{sub 2}. ABA from turgid bean leaves showed significant {sup 18}O incorporation, again with highest {sup 18}O enrichment in the carboxyl group. On the basis of {sup 18}O-labeling patterns observed in ABA from different tissues it is concluded that, despite variations in precusor pool sizes and intermediate turnover rates, there is a universal pathway of ABA biosynthesis in higher plants which involves cleavage of a larger precursor molecule, presumably an oxygenated carotenoid.

  12. Evidence for a universal pathway of abscisic acid biosynthesis in higher plants from 18O incorporation patterns

    International Nuclear Information System (INIS)

    Zeevaart, J.A.D.; Heath, T.G.; Gage, D.A.

    1989-01-01

    Previous labeling studies of abscisic acid (ABA) with 18 O 2 have been mainly conducted with water-stressed leaves. In this study, 18 O incorporation into ABA of stressed leaves of various species was compared with 18 O labeling of ABA of turgid leaves and of fruit tissue in different stages of ripening. In stressed leaves of all six species investigated, avocado (Persea americana), barley (Hordeum vulgare), bean (Phaseolus vulgaris), cocklebur (Xanthium strumarium), spinach (Spinacia oleracea), and tobacco (Nicotiana tabacum), 18 O was most abundant in the carboxyl group, whereas incorporation of a second and third 18 O in the oxygen atoms on the ring of ABA was much less prominent after 24 h in 18 O 2 . ABA from turgid bean leaves showed significant 18 O incorporation, again with highest 18 O enrichment in the carboxyl group. On the basis of 18 O-labeling patterns observed in ABA from different tissues it is concluded that, despite variations in precusor pool sizes and intermediate turnover rates, there is a universal pathway of ABA biosynthesis in higher plants which involves cleavage of a larger precursor molecule, presumably an oxygenated carotenoid

  13. The Oxygen Isotopic Composition (18O/16O) in the Dust of Comet 67P/Churyumov-Gerasimenko Measured by COSIMA On-board Rosetta

    Science.gov (United States)

    Paquette, J. A.; Engrand, C.; Hilchenbach, M.; Fray, N.; Stenzel, O. J.; Silen, J.; Rynö, J.; Kissel, J.

    2018-03-01

    The oxygen isotopic ratio 18O/16O has been measured in cometary gas for a wide variety of comets, but the only measurements in cometary dust were performed by the Stardust cometary sample return mission. Most such measurements find a value of the ratio that is consistent with Vienna Standard Mean Ocean Water (VSMOW) within errors. In this work we present the result of a measurement, using the COSIMA instrument on the Rosetta orbiter, of the oxygen isotopic ratio in dust from Comet 67P/Churyumov-Gerasimenko. Measuring the 18O/16O ratio with COSIMA is challenging for a number of reasons, but it is possible with a reasonable degree of precision. We find a result of 2.00 × 10-3 ± 1.2 × 10-4 which is consistent within errors with VSMOW.

  14. Coupled-channel calculation for cross section of fusion and barrier distribution of {}^{16,17,18}O + {}^{16}O reactions

    Science.gov (United States)

    Fereidonnejad, R.; Sadeghi, H.; Ghambari, M.

    2018-03-01

    In this work, the effect of multi-phonon excitation on heavy-ion fusion reactions has been studied and fusion barrier distributions of energy intervals near and below the Coulomb barrier have been studied for 16,17,18O + 16O reactions. The structure and deformation of nuclear projectiles have been studied. Given the adaptation of computations to experimental data, our calculations predict the behavior of reactions in intervals of energy in which experimental measurements are not available. In addition the S-factor for these reactions has been calculated. The results showed that the structure and deformation of a nuclear projectile are important factors. The S-factor, obtained in the coupled-channel calculations for the {}^{16}O + {}^{16}O, {}^{17}O +{}^{16}O and {}^{18}O +{}^{16}O reactions, showed good agreement with the experimental data and had a maximum value at an energy near 5, 4.5 and 4 MeV, respectively.

  15. Stable isotopes (2H, 18O and 13C) in groundwaters from the northwestern portion of the Guarani Aquifer System (Brazil)

    Science.gov (United States)

    Gastmans, Didier; Chang, Hung Kiang; Hutcheon, Ian

    2010-09-01

    The groundwater flow pattern of the western part of the Guarani Aquifer System (GAS), Brazil, is characterized by three regional recharge areas in the north, and a potentiometric divide in the south, which trends north-south approximately. Groundwater flow is radial from these regional recharge areas toward the center of Paraná Sedimentary Basin and toward the western outcrop areas at the border of the Pantanal Matogrossense, because of the potentiometric divide. The isotopic composition of GAS groundwater leads to understanding the paleoclimatic conditions in the regional recharge areas. The δ18O and δ2H isotopic ratios of GAS groundwaters vary, respectively, from -9.1 to -4.8‰ V-SMOW and -58.4 to -21.7‰ V-SMOW. In the recharge zones, enriched δ18O values are observed, while in the confined zone lighter δ18O values are observed. These suggest that climatic conditions were 10°C cooler than the present during the recharge of these waters. The δ13C ratios in groundwater of GAS, in the study area, vary from -19.5 to -6.5‰ VPDB, increasing along the regional flow lines toward the confined zone. This variation is related to dissolution of carbonate cement in the sandstones.

  16. Direct evidence for the origin of low-18O silicic magmas: Quenched samples of a magma chamber's partially-fused granitoid walls, Crater Lake, Oregon

    International Nuclear Information System (INIS)

    Bacon, C.R.; Adami, L.H.; Lanphere, M.A.

    1989-01-01

    Partially fused granitoid blocks were ejected in the climactic eruption of Mount Mazama, which was accompanied by collapse of Crater Lake caldera. Quartz, plagioclase, and glass in the granitoids have much lower δ 18 O values (-3.4 to +4.9per mille) than any fresh lavas of Mount Mazama and the surrounding region (+5.8 to +7.0per mille). Oxygen isotope fractionation between phases in granitoids is consistent with equilibrium at T≥900deg C following subsolidus exchange with hydrothermal fluids of meteoric origin. Assimilation of ≅ 10-20% of material similar to these granitoids can account for the O and Sr isotopic compositions of lavas and juvenile pyroclasts derived from the climactic magma chamber, many of which have δ 18 O values ≅ 0.5per mille or more lower than comparable lavas of Mount Mazama. The O isotope data provide the only clear evidence for such assimilation because the mineralogy and chemical and radiogenic isotopic compositions of the granitoids (dominantly granodiorite) are similar to those of erupted juvenile magmas. The granitoid blocks from Crater Lake serve as direct evidence for the origin of 18 O depletion in large, shallow silicic magma bodies. (orig.)

  17. Accurate experimental determination of the isotope effects on the triple point temperature of water. II. Combined dependence on the 18O and 17O abundances

    Science.gov (United States)

    Faghihi, V.; Kozicki, M.; Aerts-Bijma, A. T.; Jansen, H. G.; Spriensma, J. J.; Peruzzi, A.; Meijer, H. A. J.

    2015-12-01

    This paper is the second of two articles on the quantification of isotope effects on the triple point temperature of water. In this second article, we address the combined effects of 18O and 17O isotopes. We manufactured five triple point cells with waters with 18O and 17O abundances exceeding widely the natural abundance range while maintaining their natural 18O/17O relationship. The 2H isotopic abundance was kept close to that of VSMOW (Vienna Standard Mean Ocean Water). These cells realized triple point temperatures ranging between  -220 μK to 1420 μK with respect to the temperature realized by a triple point cell filled with VSMOW. Our experiment allowed us to determine an accurate and reliable value for the newly defined combined 18, 17O correction parameter of AO  =  630 μK with a combined uncertainty of 10 μK. To apply this correction, only the 18O abundance of the TPW needs to be known (and the water needs to be of natural origin). Using the results of our two articles, we recommend a correction equation along with the coefficient values for isotopic compositions differing from that of VSMOW and compare the effect of this new equation on a number of triple point cells from the literature and from our own institute. Using our correction equation, the uncertainty in the isotope correction for triple point cell waters used around the world will be  <1 μK.

  18. Mg and 18O Variations in the Shell of the Chilean Gastropod Concholepas concholepas Reflect SST and Growth Rate variations

    Science.gov (United States)

    Guzman, N.; Lazareth, C. E.; Poitrasson, F.; Cuif, J.; Ortlieb, L.

    2004-12-01

    To validate the use of fossil mollusc shells as recorders of environmental conditions, a primary calibration study was carried out on modern shells of the Chilean gastropod Concholepas concholepas, the so-called southern hemisphere abalone which is particularly abundant in Holocene archaeological sites. Organisms were maintained in culture tanks and feed with live mytilids. The sea water temperature in the tank was recorded every half-an-hour by an automatic device. The experiment lasted several months. Periodical marking with calcein provided a precise chronological control of the shell growth. Thus, well-dated high resolution chemical profiles could be directly compared with temperatures during shell formation. Geochemical analyses of the calcite layers include Mg, Sr and 16O/18O composition. Trace elements were analysed using Laser Ablation ICP-MS and Electron Microprobe while stable isotopes were measured on a Secondary Ion Mass spectrometry (SIMS). The shell growth rate during two months of formation varied between 30 and 140 µm/day which allows us to reach a temporal resolution for chemical profiles between a few hours and three days. The growth rate variations do not seem to be related to temperature fluctuations. Only Mg content was analytically reproducible and showed significant variations across the shells. The Mg high-resolution profiles display a grossly sinusoidal shape. Shells from different sites along the coasts of Chile showed mean Mg contents of 300 ppm and 500 ppm for mean temperatures of 17 and 20° C, respectively. This suggests a gross correlation between Mg and temperature. However, high resolution Mg results do not show an exact fitting neither with temperature nor with growth rates. Other parameters, like shell ageing as suggested by an amplitude increase observed near the edge of one of the shells, or other complex biological factors, may influence Mg incorporation into the shell. \\delta 18O values of the calcite vary between -1,5 and 2

  19. A modern Sr/Ca-δ18O-sea surface temperature calibration for Isopora corals on the Great Barrier Reef

    Science.gov (United States)

    Brenner, Logan D.; Linsley, Braddock K.; Potts, Donald C.

    2017-02-01

    Isopora (Acroporidae) is a genus of often encrusting, branching to submassive corals that are common in many shallow habitats on modern and fossil Indo-West Pacific reefs. Although abundant, Isopora is largely absent from paleoceanographic literature. The scarcity of large Porites and the abundance of Isopora retrieved from the Great Barrier Reef (GBR) on Integrated Ocean Drilling Program Expedition 325 focused paleoceanographic attention on Isopora. Here we provide the first independent high-resolution calibration of both Sr/Ca and δ18O for temperature analyses based on Isopora and demonstrate its consistency with Porites records. We developed modern skeletal Sr/Ca- and δ18O-sea surface temperature (SST) calibrations based on five modern Isopora colonies from Heron Island in the southern GBR. Pairing the coral Sr/Ca record with monthly SST data yielded Sr/Ca-SST sensitivities from -0.061 ± 0.004 (centered) to -0.083 ± 0.007 (raw) mmol/mol °C-1 based on reduced major axis regressions. These sensitivities are in the middle of the range of published Porites values and overlap most published values for Isopora, -0.075 ± 0.011 to -0.065 ± 0.011 mmol/mol °C-1. The δ18O-SST sensitivities range from -0.184 ± 0.014 (centered) to -0.185 ± 0.014 (raw) ‰ °C-1, assuming that all seasonal variation in δ18O was due to SST. These δ18O-SST sensitivities are smaller than the widely accepted value of -0.23‰ °C-1 for biogenic aragonite but are at the upper end of high-resolution Porites-defined sensitivities that are consistently less than the aforementioned established value. Our results validate the use of Isopora as an alternative source of paleoceanographic records in habitats where large massive Porites are scarce or absent.

  20. Form factors and transition charge density of 16O and 18O nuclei

    International Nuclear Information System (INIS)

    Gul'karov, I.S.; Vakil', R.Kh.

    1986-01-01

    A formula is obtained for the transition density of charge (TDC) in the Helm model. The form factors are analysed for inelastic scattering of electrons On the 16 O isotopes (O 1 + , 6.052 MeV; 2 1 + , 6.917 MeV) and on the 18 O isotopes (0 1 + , 3.630 MeV; 2 1 + , 1.982 MeV; 0 2 + , 3.919 MeV; 2 3 + , 5.250 MeV; 4 1 + , 3.553 MeV; 4 2 + , 7.114 MeV). For monopole transitions the TDC is of the volume kind, but for L=2 and 4 transitions the TDC has a maximum at approximately R (R is the nuclear surface radius). There are as well obtained the first TDC moments, i.e. the reduced transition probabilities and transition radii of 16 O and 18 O

  1. Citric acid induced W18O49 electrochromic films with enhanced optical modulation

    Science.gov (United States)

    Xie, Junliang; Song, Bin; Zhao, Gaoling; Han, Gaorong

    2018-06-01

    Electrochromic materials exhibit promising applications in energy-saving fields for their ability to control heat from outdoors. Nanostructured W18O49 has drawn attention for its one-dimensional structure to transfer charge efficiently as a remarkable electrochromic material. W18O49 bi-layer films were fabricated through a facile one-step solvothermal process with citric acid as a chelating agent. The addition of citric acid improved the deposition on the substance, and a nanostructured film with a denser layer at the bottom and a tussock-like upper layer was obtained. The bi-layer film exhibited an enhanced optical modulation of 68.7%, a coloration efficiency of 82.1 cm2/C with stability over 400 cycles, and fast response times (1.4 s and 2.3 s for bleaching and coloring), with expectation to be applied in the electrochromic field.

  2. 13C and 18O isotope enrichment by vibrational energy exchange pumping of CO

    International Nuclear Information System (INIS)

    Bergman, R.C.; Homicz, G.F.; Rich, J.W.; Wolk, G.L.

    1983-01-01

    Measurements of preferential vibration-to-vibration (V--V) pumping of high vibrational states of 13 C 16 O and 12 C 18 O in optically excited CO gas are reported. It is found that the v = 22, 25, 27, 30, and 32 states of 13 C 16 O and the v = 8, 10, and 12 states of 12 C 18 O are substantially overpopulated compared to the same states in 12 C 16 O in strongly V--V pumped CO. Such mixtures are observed to react, forming products enriched in 13 C. The results are in reasonable agreement with an analytical kinetic model of V--V pumping in binary mixtures of diatomic gases

  3. Changes of 2H and 18O enrichment of meteoric water and Pleistocene glaciation

    International Nuclear Information System (INIS)

    Harmon, R.S.; Schwarcz, H.P.

    1981-01-01

    Isotopic data on fluid inclusions and host speleothems are presented which support the hypothesis that the deltaD-delta 18 O relationship for modern meteoric waters may have changed during the Pleistocene glacial periods in response to increased ocean surface air humidity. Palaeotemperatures for five areas of east-central North America and Bermuda, calculated assuming the present deltaDdelta 18 O meteoric water relationship for fluid inclusion waters, are observed to be too low during late Pleistocene glacial periods (in some instances falling below O 0 C) while interglacial palaeotemperatures are largely equivalent to those in the areas at present. As speleothem deposition cannot occur at subzero temperatures, a possible solution to this dilemma is a shift in the intercept of the meteoric water relationship. (U.K.)

  4. Synthesis and applications of 18O standards for nuclear reaction analysis

    Science.gov (United States)

    Pitthan, E.; Corrêa, S. A.; Soares, G. V.; Radtke, C.; Stedile, F. C.

    2014-08-01

    A new method to synthesize 18O standard samples to be used in nuclear reaction analyses is proposed and investigated. This method consists of obtaining a Si18O2 film on a Si substrate using a natural abundance SiO2 film as a passivation layer to prevent the isotopically enriched film to be exposed to the atmosphere and possibly degraded by it. For that, sequential oxidation steps are performed followed by a controlled etching in aqueous hydrofluoric acid. Details of these steps are discussed as well as the stability of the synthesized samples. Applications using these standard samples in the field of alternative semiconductors to Si (SiC and Ge), used in micro and nanoelectronics are also presented.

  5. Analysis of a run-off hydrograph by means of natural 18O

    International Nuclear Information System (INIS)

    Mook, W.G.; Groeneveld, D.J.; Brouwn, A.E.; Ganswijk, A.J. van

    1974-01-01

    A deviation of the oxygen isotopic composition in precipitation from the average 18 O/ l6 O in groundwater can be considered to indicate the presence of some 18 O tracer. In this way the precipitation component in the discharge of a catchment area can be established. In a small drainage basin (650 ha) the direct peak run-off in the stream channels from a rain storm is shown to consist of rainwater above a slowly increasing base flow. The fast run-off contains two components: (1) overland flow with a time constant of 1 h; (2) a moderately declining component (time constant of 12 h) probably caused by the release of bank storage. From a complex storm it is shown that 87% infiltrates into the soil and the remaining 13% is drained within a few days. (author)

  6. Potential of ikaite to record the evolution of oceanic δ18O

    Science.gov (United States)

    Rickaby, R. E. M.; Shaw, S.; Bennitt, G.; Kennedy, H.; Zabel, M.; Lennie, A.

    2006-06-01

    A challenge in the quest to understand the sensitivity of the climate system is the separation of the competing effects of ice volume or sea level, salinity, and temperature on foraminiferal δ18O. We present precipitation experiments on the mineral ikaite, a hydrated form of calcium carbonate found in organic carbon rich deep-marine sediments, that show that the hydration waters within the ikaite crystal capture the δ18O of seawater (δ18Osw) with a fractionation factor of 1.0029 (±0.0002). The δ18Osw measures the volume of continental ice, with an overprint of local salinity. Isolation of δ18Osw by analysis of the hydration waters of sedimentary ikaite preserved at temperatures ikaite at the Last Glacial Maximum agree with estimates from modeling of pore waters that Antarctic Bottom Water was +1.4‰ ± 0.2‰ heavier.

  7. Effects of recharge and discharge on delta2H and delta18O composition and chloride concentration of high arsenic/fluoride groundwater from the Datong Basin, northern China.

    Science.gov (United States)

    Xie, Xianjun; Wang, Yanxin; Su, Chunli; Duan, Mengyu

    2013-02-01

    To better understand the effects of recharge and discharge on the hydrogeochemistry of high levels of arsenic (As) and fluoride (F) in groundwater, environmental isotopic composition (delta2H and delta18O) and chloride (Cl) concentrations were analyzed in 29 groundwater samples collected from the Datong Basin. High arsenic groundwater samples (As > 50 micog/L) were found to be enriched in lighter isotopic composition that ranged from -92 to -78 per thousand for deuterium (delta2H) and from -12.5 to -9.9 per thousand for oxygen-18 (delta18O). High F-containing groundwater (F > 1 mg/L) was relatively enriched in heavier isotopic composition and varied from -90 to -57 per thousand and from -12.2 to -6.7 per thousand for delta2H and delta18O, respectively. High chloride concentrations and delta18O values were primarily measured in groundwater samples from the northern and southwestern portions of the study area, indicating the effect of evaporation on groundwater. The observation of relatively homogenized and low delta18O values and chloride concentrations in groundwater samples from central part of the Datong Basin might be a result of fast recharge by irrigation returns, which suggests that irrigation using arsenic-contaminated groundwater affected the occurrence of high arsenic-containing groundwater in the basin.

  8. Elastic and inelastic scattering of the 14C + 18O nuclei

    Directory of Open Access Journals (Sweden)

    A. T. Rudchik

    2010-12-01

    Full Text Available New angular-distribution data of 14С + 18О elastic and inelastic scattering at the energy Elab(18O = 105 MeV were obtained firstly. The data were analysed within the optical model and coupled-reaction-channels methods including contributions from most simple transfer reactions. The 14С + 18О potential parameters were deduced. Isotopic differenc-es of the 12, 13, 14С + 18О and 14С + 16, 18О potentials were investigated.

  9. Regional groundwater flow in the Atikokan Research Area : simulation of 18O and 3H distributions

    International Nuclear Information System (INIS)

    Ophori, D.U.; Chan, Tin.

    1994-09-01

    AECL is investigating a concept for disposing of nuclear fuel waste deep in plutonic rock of the Canadian Shield. As part of this investigation, we have performed a model simulation of regional groundwater flow in the Atikokan Research Area, a fractured plutonic rock environment of the Canadian Shield, and used the distribution of oxygen-18 ( 18 O) and tritium ( 3 H) in groundwater to test the model. At the first stage of model calibration, groundwater flow was simulated using a three-dimensional finite-element code, MOTIF, in conjunction with a conceptual framework model derived from field geological, geophysical and hydrogeological data. Hydraulic parameters (permeability and porosity) were systematically varied until simulated recharge rates to the water table compared favourably with estimated recharge rates based on stream flow analysis. At the second stage, vertical average linear groundwater velocities from the first stage of the calibration process were combined with conceptualized one-dimensional models of the system to generate depth concentration profiles of 18 O and 3 H. Recharge-, midline-and discharge area models of both the fracture zones and the rock mass were employed. The simulated profiles formed 'envelopes' around all field 18 O and 3 H data, indicating that the calibrated velocities used in the model are reasonable. The models demonstrate that the scatter of δ 18 O and 3 H field data from the Atikokan Research Area is consistent with the groundwater flow model predictions and can be explained by the complexity arising from different hydraulic regimes (recharge, midline, discharge) and hydrogeologic environments (fracture zones, rock mass) of the regional flow system. 50 refs., 14 figs., 3 tabs

  10. Does δ18O of O2 record meridional shifts in tropical rainfall?

    Science.gov (United States)

    Seltzer, Alan M.; Buizert, Christo; Baggenstos, Daniel; Brook, Edward J.; Ahn, Jinho; Yang, Ji-Woong; Severinghaus, Jeffrey P.

    2017-10-01

    Marine sediments, speleothems, paleo-lake elevations, and ice core methane and δ18O of O2 (δ18Oatm) records provide ample evidence for repeated abrupt meridional shifts in tropical rainfall belts throughout the last glacial cycle. To improve understanding of the impact of abrupt events on the global terrestrial biosphere, we present composite records of δ18Oatm and inferred changes in fractionation by the global terrestrial biosphere (ΔɛLAND) from discrete gas measurements in the WAIS Divide (WD) and Siple Dome (SD) Antarctic ice cores. On the common WD timescale, it is evident that maxima in ΔɛLAND are synchronous with or shortly follow small-amplitude WD CH4 peaks that occur within Heinrich stadials 1, 2, 4, and 5 - periods of low atmospheric CH4 concentrations. These local CH4 maxima have been suggested as markers of abrupt climate responses to Heinrich events. Based on our analysis of the modern seasonal cycle of gross primary productivity (GPP)-weighted δ18O of terrestrial precipitation (the source water for atmospheric O2 production), we propose a simple mechanism by which ΔɛLAND tracks the centroid latitude of terrestrial oxygen production. As intense rainfall and oxygen production migrate northward, ΔɛLAND should decrease due to the underlying meridional gradient in rainfall δ18O. A southward shift should increase ΔɛLAND. Monsoon intensity also influences δ18O of precipitation, and although we cannot determine the relative contributions of the two mechanisms, both act in the same direction. Therefore, we suggest that abrupt increases in ΔɛLAND unambiguously imply a southward shift of tropical rainfall. The exact magnitude of this shift, however, remains under-constrained by ΔɛLAND.

  11. Does δ18O of O2 record meridional shifts in tropical rainfall?

    Directory of Open Access Journals (Sweden)

    A. M. Seltzer

    2017-10-01

    Full Text Available Marine sediments, speleothems, paleo-lake elevations, and ice core methane and δ18O of O2 (δ18Oatm records provide ample evidence for repeated abrupt meridional shifts in tropical rainfall belts throughout the last glacial cycle. To improve understanding of the impact of abrupt events on the global terrestrial biosphere, we present composite records of δ18Oatm and inferred changes in fractionation by the global terrestrial biosphere (ΔεLAND from discrete gas measurements in the WAIS Divide (WD and Siple Dome (SD Antarctic ice cores. On the common WD timescale, it is evident that maxima in ΔεLAND are synchronous with or shortly follow small-amplitude WD CH4 peaks that occur within Heinrich stadials 1, 2, 4, and 5 – periods of low atmospheric CH4 concentrations. These local CH4 maxima have been suggested as markers of abrupt climate responses to Heinrich events. Based on our analysis of the modern seasonal cycle of gross primary productivity (GPP-weighted δ18O of terrestrial precipitation (the source water for atmospheric O2 production, we propose a simple mechanism by which ΔεLAND tracks the centroid latitude of terrestrial oxygen production. As intense rainfall and oxygen production migrate northward, ΔεLAND should decrease due to the underlying meridional gradient in rainfall δ18O. A southward shift should increase ΔεLAND. Monsoon intensity also influences δ18O of precipitation, and although we cannot determine the relative contributions of the two mechanisms, both act in the same direction. Therefore, we suggest that abrupt increases in ΔεLAND unambiguously imply a southward shift of tropical rainfall. The exact magnitude of this shift, however, remains under-constrained by ΔεLAND.

  12. Preparation of aligned W{sub 18}O{sub 49} nanowire clusters with high photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ning [State Key Laboratory of Inorganic Synthesis & Preparative Chemistry, Jilin University, Changchun 130012 (China); Zhao, Yafei, E-mail: zhaoyafei007@126.com [State Key Laboratory of Inorganic Synthesis & Preparative Chemistry, Jilin University, Changchun 130012 (China); School of Chemical Engineering and Energy, Zhengzhou University, Zhengzhou, Henan 450001 (China); Lu, Yanjie [School of Chemical Engineering and Energy, Zhengzhou University, Zhengzhou, Henan 450001 (China); Zhu, Guangshan, E-mail: zhugs@jlu.edu.cn [State Key Laboratory of Inorganic Synthesis & Preparative Chemistry, Jilin University, Changchun 130012 (China)

    2017-04-15

    Highlights: • Aligned W{sub 18}O{sub 49} nanowire clusters were prepared by a facile hydrothermal method. • W{sub 18}O{sub 49} has unique structure, high degree of crystallinity and large surface area. • W{sub 18}O{sub 49} nanowire clusters exhibited high photocatalytic degradation activity. - Abstract: The aligned W{sub 18}O{sub 49} nanowire clusters were synthesized via a facile and economic ethanol-assisted hydrothermal method using peroxopolytungstic acid as precursor. Results show that the as-prepared W{sub 18}O{sub 49} exhibits a high yield and ultrathin structure with preferential growth direction along [0 1 0]. The amount of peroxopolytungstic acid and reaction time play significant role on the morphology of W{sub 18}O{sub 49} nanowires. The nanowires have unique structure, high degree of crystallinity, large specific surface area, and large number of defects such as oxygen vacancies, which are responsible for their high photocatalytic performance for degradation of methylene blue. The photocatalytic conversion of methylene blue can reach above 98% after degradation. W{sub 18}O{sub 49} also exhibits good photodegradation stability after five cycles of reuse. The results demonstrate that the as-prepared W{sub 18}O{sub 49} nanowire clusters are expected to be a promising material for applications in the field of environment.

  13. Isotopic effects in elastic and inelastic 12,13C + 16,18O scattering

    Directory of Open Access Journals (Sweden)

    A. T. Rudchik

    2010-09-01

    Full Text Available New angular-distribution data of 13С + 18О elastic and inelastic scattering at the energy Elab(18O = 105 MeV were obtained for the transitions to the ground and excited states 3.088 MeV(1/2+, 3.555 MeV (1/2-, 3.854 MeV (5/2+ of 13С and 1.982 MeV (2+, 3.555 MeV (4+, 3.921 MeV (2+, 4.456 MeV (1-, 5.098 MeV (3-, 5.260 MeV (2+ of 18O. These and the 13С + 18О elastic scattering data taken from the literature at the energies Elab(18O = 15, 20, 24, 31 MeV and Elab(13С = 24 MeV were analysed within the optical model and coupled-reaction-channels methods. Sets of 13С + 18О optical potential parameters and their energy dependence were obtained. Contributions of potential scattering and transfer reactions to the elastic and inelastic channels of 13С + 18О scattering were studied. Isotopic differences (effects in 12, 13С + 16, 18О optical potential parameters were investigated.

  14. NanoSIMS50 analyses of Ar/18O2 plasma-treated Escherichia coli bacteria

    International Nuclear Information System (INIS)

    Clément, F; Lecoq, E; Duday, D; Audinot, J-N; Lentzen, E; Penny, C; Cauchie, H-M; Choquet, P; Belmonte, T

    2011-01-01

    Reactive oxygen species (ROS) can be produced by electrical discharges and can be transported in uncharged regions by gas flows, in the so-called afterglows. These species are well known to have bactericidal effects but interaction mechanisms that occur with living micro-organisms remain misunderstood. In order to better understand these interactions, new analysis approaches are necessary. High-lateral-resolution secondary ion mass spectrometry (NanoSIMS) is one of the most promising ways of retrieving additional information on bacteria plasma inactivation mechanisms by combining isotopic imaging of plasma-treated bacteria and the use of 18 O 2 as process gas. Indeed, this technology combines a lateral resolution of a few tens of nanometres that is sufficient to image the interior of bacteria, and a high mass resolution allowing detection of isotopes present in low quantities (a few ppm or lower) within the bacteria. The present paper deals with Ar- 18 O 2 (2%) plasma treatment, through low-pressure microwave late afterglows, of Escherichia coli bacteria and their elemental and isotopic imaging by NanoSIMS. E. coli bacteria have been exposed to this reactive medium for varying treatment duration while keeping all other parameters unchanged. Our main goal is to determine whether the quantity of 18 O fixed in treated bacteria and the NanoSIMS50 lateral resolution are sufficient to give additional information on E. coli bacteria-plasma interaction. (paper)

  15. Letter: Observation of the 16O/18O exchange during electrospray ionization.

    Science.gov (United States)

    Kostyukevich, Yury; Kononikhin, Alexey; Popov, Igor; Nikolaev, Eugene

    2015-01-01

    Isotopic exchange approach coupled to high-resolution mass spectrometry has become the power analytical approach for a wide range of analytical and bioanalyticall applications. Considerable efforts have been dedicated to developing fast exchange techniques directly in the ionization source. But all such methods are limited to the hydrogen/deuterium exchange approaches. In this paper we demonstrate that certain types of oxygen atoms can also be exchanged for (18)O on the time scale of the ionization process. Using HIO(3) and NaIO(4) and by infusing the heavy water H(2)(18)O in the ESI source we have demonstrated that it is possible to obtain a high level of oxygen exchange. It was observed that the rate of this exchange depends to a large extent on the temperature of the desolvating capillary of the mass spectrometer. Several other species, such as peptides, oligonucleotides and low weight organic molecules, were subjected to in-ESI (16)O/(18)O exchange but the exchange was not observed.

  16. Assessing the Contribution of Sea Surface Temperature and Salinity to Coral δ18O using a Weighted Forward Model

    Science.gov (United States)

    Horlick, K. A.; Thompson, D. M.; Anderson, D. M.

    2015-12-01

    The isotopic ratio of 16O/18O18O) in coral carbonate skeletons is a robust, high-resolution proxy for sea surface temperature (SST) and sea surface salinity (SSS) variability predating the instrumental record. Although SST and δ18O-water (correlated to SSS) variability both contribute to the δ18O signal in the coral carbonate archive, the paucity and limited temporal span of SST and SSS instrumental observations limit the ability to differentiate respective SST and SSS contribution to each δ18O record. From instrumental datasets such as HadISST v.3, ERSST, SODA, and Delcroix (2011), we forward model the δ18O ("pseudoproxy") signal using the linear bivariate forward model from Thompson 2011 ("pseudoproxy"= a1(SST)+a2(SSS)). By iteratively weighting (between 0 and 1 by 0.005) the relative contribution of SST and SSS terms to the δ18O "pseudoproxy" following Gorman et al. 2012 method, we derive the percent contributions of SST and SSS to δ18O at each site based on the weights that produce the optimal correlation to the observed coral δ18O signal. A Monte Carlo analysis of error propagation in the weighted and unweighted pseudoproxy time series was used to determine how well the weighted and unweighted forward models captured observed δ18O variance. Across the south-western Pacific (40 sites) we found that SST contributes from less than 8 to more than 78% of the variance. This work builds upon this simple forward model of coral δ18O and improves our understanding of potential sources of differences in the observed and forward modeled δ18O variability. These results may also improve SST and SSS reconstructions from corals by highlighting the reef areas whose coral δ18O signal is most heavily influenced by SST and SSS respectively. Using an inverse approach, creating a transfer function, local SST and SSS could also be reconstructed based on the site-specific weights and observed coral δ18O time series.

  17. Structure of 19O from measurement and R-matrix analysis of sigma(theta) for 18O(n,n)18O and 18O(n,n')18Osup(*) (1.98 MeV)

    International Nuclear Information System (INIS)

    Koehler, P.E.; Knox, H.D.; Resler, D.A.; Lane, R.O.

    1986-01-01

    Differential cross sections for neutrons elastically scattered from 18 O and inelastically scattered to the first excited state 18 Osup(*) (1.98 MeV) have been measured at forty-two incident energies for 5.0 19 O of 8.7 to 11.1 MeV. The cross sections were measured at eleven laboratory angles per energy from 20 0 to 160 0 and show considerable resonance structure. These new elastic and inelastic 1.98 MeV level data have been analyzed together with previously published cross sections for 0 19 O. The new assignments are compared to previous work where possible. Several previous assignments for resonances in the 0 19 F for the newly assigned levels in 19 O. On the basis of spin, parity, excitation energy and a comparison of reduced neutron widths in 19 O with reduced proton widths in 19 F, six previously-identified T=3/2 analogs were verified and eight new T=3/2 analogs were tentatively assigned. Comparisons with existing theoretical work are discussed. (orig.)

  18. Comprehensive inter-laboratory calibration of reference materials for δ18O versus VSMOW using various on-line high-temperature conversion techniques

    Science.gov (United States)

    Brand, Willi A.; Coplen, Tyler B.; Aerts-Bijma, Anita T.; Bohlke, John Karl; Gehre, Matthias; Geilmann, Heike; Groning, Manfred; Jansen, Henk G.; Meijer, Harro A. J.; Mroczkowski, Stanley J.; Qi, Haiping; Soergel, Karin; Stuart-Williams, Hilary; Weise, Stephan M.; Werner, Roland A.

    2009-01-01

    Internationally distributed organic and inorganic oxygen isotopic reference materials have been calibrated by six laboratories carrying out more than 5300 measurements using a variety of high-temperature conversion techniques (HTC) in an evaluation sponsored by the International Union of Pure and Applied Chemistry (IUPAC). To aid in the calibration of these reference materials, which span more than 125‰, an artificially enriched reference water (δ18O of +78.91‰) and two barium sulfates (one depleted and one enriched in 18O) were prepared and calibrated relative to VSMOW2 and SLAP reference waters. These materials were used to calibrate the other isotopic reference materials in this study, which yielded:Reference materialδ18O and estimated combined uncertainty IAEA-602 benzoic acid+71.28 ± 0.36‰USGS35 sodium nitrate+56.81 ± 0.31‰IAEA-NO-3 potassium nitrate+25.32 ± 0.29‰IAEA-601 benzoic acid+23.14 ± 0.19‰IAEA-SO-5 barium sulfate+12.13 ± 0.33‰NBS 127 barium sulfate+8.59 ± 0.26‰VSMOW2 water0‰IAEA-600 caffeine−3.48 ± 0.53‰IAEA-SO-6 barium sulfate−11.35 ± 0.31‰USGS34 potassium nitrate−27.78 ± 0.37‰SLAP water−55.5‰The seemingly large estimated combined uncertainties arise from differences in instrumentation and methodology and difficulty in accounting for all measurement bias. They are composed of the 3-fold standard errors directly calculated from the measurements and provision for systematic errors discussed in this paper. A primary conclusion of this study is that nitrate samples analyzed for δ18O should be analyzed with internationally distributed isotopic nitrates, and likewise for sulfates and organics. Authors reporting relative differences of oxygen-isotope ratios (δ18O) of nitrates, sulfates, or organic material should explicitly state in their reports the δ18O values of two or more internationally distributed nitrates (USGS34, IAEA-NO-3, and USGS35), sulfates (IAEA-SO-5, IAEA

  19. 7Li(18O, 17N8Be reaction and the 17N + 8Be-potential

    Directory of Open Access Journals (Sweden)

    A. T. Rudchik

    2010-12-01

    Full Text Available Angular distributions of the 7Li(18O, 17N8Be reaction were measured for the transitions to the ground states of 8Be and 17N and excited states of 17N at the energy Elab(18O = 114 MeV. The data were analyzed with coupled-reaction-channels method for one- and two-step transfers of nucleons and clusters. In the analysis, the 7Li + 18O potential de-duced in the analysis of the elastic 7Li + 18O-scattering data as well as shell-model spectroscopic amplitudes of trans-ferred nucleons and clusters were used. Parameters of the 8Be + 17N potential were deduced using the reaction data. Contributions of different one- and two-step transfers in the 7Li(18O, 17N8Be reaction cross-section was studied.

  20. Solar cycles in the last centuries in 10Be and delta18O in polar ice and in thermoluminescence signals of a sea sediment

    International Nuclear Information System (INIS)

    Cini Castagnoli, G.; Bonino, G.; Galli, M.; Beer, J.

    1984-01-01

    The cyclogram method of time series analysis has been used to analyse 10 Be data (1181-1800 AD) and delta 18 O data (1181-1960 AD) from an artic ice core and thermoluminescence data (1181-1960 AD) from a Mediterranean sediment core. The 10 Be concentrations were determined at the ETH Zurich. The delta 18 O values were measured at the University of Copenhagen. The TL measurements were performed at the Istituto di Cosmo-geofisica del C.N.R., Torino. Common mean periodicities of 10.75 y are found for the period 1505 to 1710 AD in TL and 10 Be and of 11.4 y for the period 1715 to 1880 in TL and delta 18 O. This periodicity was found in the solar sunspot (Rsub(z)) series analysed in the same way, from 1825 to 1905. This supports the argument that the common periodicities found in the long-running series are peculiar of the solar activity in the past

  1. Oxygen isotopes in tree rings record variation in precipitation δ18O and amount effects in the south of Mexico.

    Science.gov (United States)

    Brienen, Roel J W; Hietz, Peter; Wanek, Wolfgang; Gloor, Manuel

    2013-12-01

    [1] Natural archives of oxygen isotopes in precipitation may be used to study changes in the hydrological cycle in the tropics, but their interpretation is not straightforward. We studied to which degree tree rings of Mimosa acantholoba from southern Mexico record variation in isotopic composition of precipitation and which climatic processes influence oxygen isotopes in tree rings ( δ 18 O tr ). Interannual variation in δ 18 O tr was highly synchronized between trees and closely related to isotopic composition of rain measured at San Salvador, 710 km to the southwest. Correlations with δ 13 C, growth, or local climate variables (temperature, cloud cover, vapor pressure deficit (VPD)) were relatively low, indicating weak plant physiological influences. Interannual variation in δ 18 O tr correlated negatively with local rainfall amount and intensity. Correlations with the amount of precipitation extended along a 1000 km long stretch of the Pacific Central American coast, probably as a result of organized storm systems uniformly affecting rainfall in the region and its isotope signal; episodic heavy precipitation events, of which some are related to cyclones, deposit strongly 18 O-depleted rain in the region and seem to have affected the δ 18 O tr signal. Large-scale controls on the isotope signature include variation in sea surface temperatures of tropical north Atlantic and Pacific Ocean. In conclusion, we show that δ 18 O tr of M . acantholoba can be used as a proxy for source water δ 18 O and that interannual variation in δ 18 O prec is caused by a regional amount effect. This contrasts with δ 18 O signatures at continental sites where cumulative rainout processes dominate and thus provide a proxy for precipitation integrated over a much larger scale. Our results confirm that processes influencing climate-isotope relations differ between sites located, e.g., in the western Amazon versus coastal Mexico, and that tree ring isotope records can help in

  2. A urinary metabolite of {Delta}{sup 1}-tetrahydrocannabinol. The first synthesis of 4``-hydroxy-{Delta}{sup 1}-tetrahydrocannabinol-7-oic acid labelled with deuterium

    Energy Technology Data Exchange (ETDEWEB)

    Szirmai, Maria; Odqvist, Helena [Uppsala Univ. (Sweden). Dept. of Pharmacognosy; Halldin, M.M. [Karolinska Inst., Stockholm (Sweden). Dept. of Pharmacology

    1996-04-01

    The first synthesis of 4``-hydroxy-{Delta}-{sup 1}-THC-7-oic acid, one of the three major metabolites of {Delta}{sup 1}-THC identified in human urine is discussed. Methyl 4-(3,5-dihydroxyphenyl)butanoate was prepared from 3,5-diydroxybenzoic acid in an overall yield of 15% was condensed with a terpene synthon under acidic conditions followed by hydrolysis and conversion of the 4``-carboxylic acid function to the corresponding methyl ketone using methyllithium. Reduction with NaBH{sub 4} afforded the secondary alcohol in the side-chain. Acetylation and removal of the 1,3-dithiane masking group gave the aldehyde in C-7-position which was further oxidized using NaClO{sub 2} followed by deacetylation to give the desired metabolite. The same procedure may be used for the synthesis of unlabelled 4``-hydroxy-{Delta}{sup 1}-THC-7-oic acid. (author).

  3. Reconstructing lake evaporation history and the isotopic composition of precipitation by a coupled δ18O-δ2H biomarker approach

    Science.gov (United States)

    Hepp, Johannes; Tuthorn, Mario; Zech, Roland; Mügler, Ines; Schlütz, Frank; Zech, Wolfgang; Zech, Michael

    2015-10-01

    Over the past decades, δ18O and δ2H analyses of lacustrine sediments became an invaluable tool in paleohydrology and paleolimnology for reconstructing the isotopic composition of past lake water and precipitation. However, based on δ18O or δ2H records alone, it can be challenging to distinguish between changes of the precipitation signal and changes caused by evaporation. Here we propose a coupled δ18O-δ2H biomarker approach that provides the possibility to disentangle between these two factors. The isotopic composition of long chain n-alkanes (n-C25, n-C27, n-C29, n-C31) were analyzed in order to establish a 16 ka Late Glacial and Holocene δ2H record for the sediment archive of Lake Panch Pokhari in High Himalaya, Nepal. The δ2Hn-alkane record generally corroborates a previously established δ18Osugar record reporting on high values characterizing the deglaciation and the Older and the Younger Dryas, and low values characterizing the Bølling and the Allerød periods. Since the investigated n-alkane and sugar biomarkers are considered to be primarily of aquatic origin, they were used to reconstruct the isotopic composition of lake water. The reconstructed deuterium excess of lake water ranges from +57‰ to -85‰ and is shown to serve as proxy for the evaporation history of Lake Panch Pokhari. Lake desiccation during the deglaciation, the Older Dryas and the Younger Dryas is affirmed by a multi-proxy approach using the Hydrogen Index (HI) and the carbon to nitrogen ratio (C/N) as additional proxies for lake sediment organic matter mineralization. Furthermore, the coupled δ18O and δ2H approach allows disentangling the lake water isotopic enrichment from variations of the isotopic composition of precipitation. The reconstructed 16 ka δ18Oprecipitation record of Lake Panch Pokhari is well in agreement with the δ18O records of Chinese speleothems and presumably reflects the Indian Summer Monsoon variability.

  4. Effect of photosynthesis on the abundance of 18O13C16O in atmospheric CO2

    Science.gov (United States)

    Hofmann, Magdalena E. G.; Pons, Thijs L.; Ziegler, Martin; Lourens, Lucas J.; Röckmann, Thomas

    2016-04-01

    The abundance of the isotopologue 18O13C16O (Δ47) in atmospheric air is a promising new tracer for the atmospheric carbon cycle (Eiler and Schauble, 2004; Affek and Eiler, 2006; Affek et al., 2007). The large gross fluxes in CO2 between the atmosphere and biosphere are supposed to play a major role in controlling its abundance. Eiler and Schauble (2004) set up a box model describing the effect of air-leaf interaction on the abundance of 18O13C16O in atmospheric air. The main assumption is that the exchange between CO2 and water within the mesophyll cells will imprint a Δ47 value on the back-diffusing CO2 that reflects the leaf temperature. Additionally, kinetic effects due to CO2 diffusion into and out of the stomata are thought to play a role. We investigated the effect of photosynthesis on the residual CO2 under controlled conditions using a leaf chamber set-up to quantitatively test the model assumptions suggested by Eiler and Schauble (2004). We studied the effect of photosynthesis on the residual CO2 using two C3 and one C4 plant species: (i) sunflower (Helianthus annuus), a C3 species with a high leaf conductance for CO2 diffusion, (ii) ivy (Hedera hibernica), a C3 species with a low conductance, and (iii), maize (Zea mays), a species with the C4 photosynthetic pathway. We also investigated the effect of different light intensities (photosynthetic photon flux density of 200, 700 and 1800 μmol m2s-1), and thus, photosynthetic rate in sunflower and maize. A leaf was mounted in a cuvette with a transparent window and an adjustable light source. The air inside was thoroughly mixed, making the composition of the outgoing air equal to the air inside. A gas-mixing unit was attached at the entrance of the cuvette that mixed air with a high concentration of scrambled CO2 with a Δ47 value of 0 to 0.1‰ with CO2 free air to set the CO2 concentration of ingoing air at 500 ppm. The flow rate through the cuvette was adjusted to the photosynthetic activity of the leaf

  5. Temperature and vital effect controls on Bamboo coral (Isididae) isotopegeochemistry: A test of the "lines method"

    Energy Technology Data Exchange (ETDEWEB)

    Hill, T M; Spero, H J; Guilderson, T P; LaVigne, M; Clague, D; Macalello, S; Jang, N

    2011-03-01

    Deep-sea bamboo corals hold promise as long-term climatic archives, yet little information exists linking bamboo coral geochemistry to measured environmental parameters. This study focuses on a suite of 10 bamboo corals collected from the Pacific and Atlantic basins (250-2136 m water depth) to investigate coral longevity, growth rates, and isotopic signatures. Calcite samples for stable isotopes and radiocarbon were collected from the base the corals, where the entire history of growth is recorded. In three of the coral specimens, samples were also taken from an upper branch for comparison. Radiocarbon and growth band width analyses indicate that the skeletal calcite precipitates from ambient dissolved inorganic carbon and that the corals live for 150-300 years, with extension rates of 9-128 {micro}m/yr. A linear relationship between coral calcite {delta}{sup 18}O and {delta}{sup 13}C indicates that the isotopic composition is influenced by vital effects ({delta}{sup 18}O:{delta}{sup 13}C slope of 0.17-0.47). As with scleractinian deep-sea corals, the intercept from a linear regression of {delta}{sup 18}O versus {delta}{sup 13}C is a function of temperature, such that a reliable paleotemperature proxy can be obtained, using the 'lines method.' Although the coral calcite {delta}{sup 18}O:{delta}{sup 13}C slope is maintained throughout the coral base ontogeny, the branches and central cores of the bases exhibit {delta}{sup 18}O:{delta}{sup 13}C values that are shifted far from equilibrium. We find that a reliable intercept value can be derived from the {delta}{sup 18}O:{delta}{sup 13}C regression of multiple samples distributed throughout one specimen or from multiple samples within individual growth bands.

  6. Simultaneous analysis of 17O/16O, 18O/16O and 2H/1H of gypsum hydration water by cavity ring‐down laser spectroscopy

    Science.gov (United States)

    Mather, Ian; Rolfe, James; Evans, Nicholas P.; Herwartz, Daniel; Staubwasser, Michael; Hodell, David A.

    2015-01-01

    Rationale The recent development of cavity ring‐down laser spectroscopy (CRDS) instruments capable of measuring 17O‐excess in water has created new opportunities for studying the hydrologic cycle. Here we apply this new method to studying the triple oxygen (17O/16O, 18O/16O) and hydrogen (2H/1H) isotope ratios of gypsum hydration water (GHW), which can provide information about the conditions under which the mineral formed and subsequent post‐depositional interaction with other fluids. Methods We developed a semi‐automated procedure for extracting GHW by slowly heating the sample to 400°C in vacuo and cryogenically trapping the evolved water. The isotopic composition (δ17O, δ18O and δ2H values) of the GHW is subsequently measured by CRDS. The extraction apparatus allows the dehydration of five samples and one standard simultaneously, thereby increasing the long‐term precision and sample throughput compared with previous methods. The apparatus is also useful for distilling brines prior to isotopic analysis. A direct comparison is made between results of 17O‐excess in GHW obtained by CRDS and fluorination followed by isotope ratio mass spectrometry (IRMS) of O2. Results The long‐term analytical precision of our method of extraction and isotopic analysis of GHW by CRDS is ±0.07‰ for δ17O values, ±0.13‰ for δ18O values and ±0.49‰ for δ2H values (all ±1SD), and ±1.1‰ and ±8 per meg for the deuterium‐excess and 17O‐excess, respectively. Accurate measurement of the 17O‐excess values of GHW, of both synthetic and natural samples, requires the use of a micro‐combustion module (MCM). This accessory removes contaminants (VOCs, H2S, etc.) from the water vapour stream that interfere with the wavelengths used for spectroscopic measurement of water isotopologues. CRDS/MCM and IRMS methods yield similar isotopic results for the analysis of both synthetic and natural gypsum samples within analytical error of the two methods. Conclusions We

  7. Partial wave analysis of the 18O(p,α0)15N reaction

    International Nuclear Information System (INIS)

    Wild, L.W.J.; Spicer, B.M.

    1979-01-01

    A partial wave analysis of the differential cross sections for the 18 O(p,α 0 ) 15 N reaction has been carried out applying the formalism of Blatt and Biedenharn (1952), made specific for this reaction. The differential cross sections, measured at 200 keV intervals from 6.6 to 10.4 MeV bombarding energy, were subjected to least-squares fitting to this specific analytic expression. Two resonances were given by the analysis, the 19 F states being at 14.71+-0.07 MeV (1/2 - ) and 14.80 + 0.07 MeV (1/2) +

  8. {sup 18}O/{sup 16}O determination in organic matter

    Energy Technology Data Exchange (ETDEWEB)

    Saurer, M.; Siegwolf, R. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    The oxygen isotope ratio in plant material can be used to deduce information about the climate and the environment. We present a simple and fast continuous-flow technique for the determination of the {sup 18}O/{sup 16}O ratio in organic matter. In this method the samples are thermally decomposed in the presence of glassy carbon and the evolving monoxide is used to determine the oxygen ratio. Not only cellulose but also nitrogen-containing materials can be processed when interfering gases (mainly N{sub 2}) are separated from CO by gas chromatography. (author) 2 figs., 2 refs.

  9. Comparison of one and two-neutron transfer near the Coulomb barrier for the 27Al(18O, 16O)29Al, 27Al(18O, 17O)28Al and 27Al(13C, 12C)28Al reactions

    International Nuclear Information System (INIS)

    Schiller, S.A.; Eck, J.S.

    1975-01-01

    Total reaction cross sections for the transfer reactions 27 Al( 18 O, 16 O) 29 Al, 27 Al( 18 O, 17 O) 28 Al and 27 Al( 13 C, 12 C) 28 Al are reported for center-of-mass energies between 13 and 20 MeV for 18 O projectiles and between 11 and 17.5 MeV for 13 C projectiles. The reaction products, 29 Al, and 28 Al, beta decay to 29 Si and 28 Si, respectively, and the subsequent γ decays of 29 Si and 28 Si were measured. Due to the relatively long beta decay half lives, data were taken in a beam-off mode, resulting in very clean spectra. Total cross sections were calculated and compared with a theoretical model for barrier penetration proposed by C.Y. Wong. Differences between 18 O induced one and two-neutron total transfer reaction cross sections are discussed. (orig.) [de

  10. Contribution of nuclear microanalysis and of 18O tracer technique to study the oxygen sublattice in high Tc superconducting thin films

    International Nuclear Information System (INIS)

    Siejka, J.

    1994-01-01

    At first a short review of IBA contribution to the determination of composition and structure, including phonon properties of high T c superconducting oxides is presented. In the second part, IBA contribution to the elucidation of the mechanisms of thin film growth is presented. The emphasis is on the complementarity of IBA, Raman spectroscopy and XRD techniques to characterize thin films of high T c superconducting oxides. In the third part, some recent results related mainly to YBaCuO films grown on (100) oriented single crystalline bulk materials (MgO, LaAlO 3 , SrTiO 3 ) is discussed. In these experiments, IBA, XRD and Raman spectroscopies were used to study the oxygen content in a series of YBaCuO films prepared in different conditions of pressure and temperature. In the case of c-axis oriented films a good agreement between these three methods was found for the films cooled down at high oxygen pressure and a significant disagreement for the films cooled down at low oxygen pressure, showing structures with anomalous c-axis parameter. In the case of a-axis oriented films grown on SrTiO 3 substrates it was found that the low T c values (∼ 70-80 K) are not correlated with the oxygen content but rather with a disorder in the oxygen sublattice. The disorder in the oxygen sublattice was studied using the 16 O(α, α) 16 O resonance in random and channeling geometry. These results are correlated with the data provided by Raman spectroscopy. The 18 O tracer technique was used to estimate the diffusion coefficient in the a-axis oriented YBaCuO films showing a huge anisotropy of the 18 O labelling. Combining Raman and IBA techniques, the selective 18 O labelling of the CuO chain-planes was evidenced. The defects in the 18 O enriched CuO chain-planes were studied using the 18 O(p, α) 15 N nuclear resonant reaction in random and channeling geometries. Some preliminary results related to roughness of YBaCuO films are also discussed. The physical implications of these

  11. Assessing the fidelity of marine vertebrate microfossil δ18O signatures and their potential for palaeo-ecological and -climatic reconstructions

    Energy Technology Data Exchange (ETDEWEB)

    Roelofs, Brett; Barham, Milo; Cliff, John; Joachimski, Michael; Martin, Laure; Trinajstic, Kate

    2017-01-01

    Conodont biogenic apatite has become a preferred analytical target for oxygen isotope studies investigating ocean temperature and palaeoclimate change in the Palaeozoic. Despite the growing application in geochemical based palaeoenvironmental reconstructions, the paucity or absence of conodont fossils in certain facies necessitates greater flexibility in selection of robust oxygen bearing compounds for analysis. Microvertebrates offer a potential substitute for conodonts from the middle Palaeozoic. Microvertebrate bioapatite is particularly advantageous given a fossil record extending to the present with representatives across freshwater to fully marine environments, thus widening the scope of oxygen isotope studies on bioapatite. However, significant tissue heterogeneity within vertebrates and differential susceptibility of these tissues to diagenetic alteration have been raised as potential problems affecting the reliability of the oxygen isotope ratios as palaeoclimate proxies. Pristine microvertebrate and co-occurring conodont fossils from the Late Devonian and Early Carboniferous of the Lennard Shelf, Canning Basin, Western Australia, were analysed using bulk (gas isotope ratio mass spectrometry) and in-situ (secondary ion mass spectrometry) methodologies, with the latter technique allowing investigation of specific tissues within vertebrate elements. The δ18Oconodont results may be interpreted in terms of palaeolatitudinally and environmentally sensible palaeotemperatures and provide a baseline standard for comparison against δ18Omicrovertebrate values. Despite an absence of obvious diagenetic influences, GIRMS of microvertebrate denticles yielded δ18O values depleted by 2-4 ‰ relative to co-occurring conodonts. SIMS analysis of hypermineralised tissues in both scales and teeth produced δ18O values comparable with those of associated conodonts. The susceptibility of porous phosphatic fossil tissues to microbial activity, fluid interaction and

  12. Multi-isotopic composition (δ7Li-δ11B-δD-δ18O) of rainwaters in France: Origin and spatio-temporal characterization

    International Nuclear Information System (INIS)

    Millot, Romain; Petelet-Giraud, Emmanuelle; Guerrot, Catherine; Negrel, Philippe

    2010-01-01

    Research highlights: → A contour map of France for δ 18 O was drawn after compiling data that included more than 400 values from all of France. → The seasonal effect (i.e. the month or rainfall amount) is not the main controlling factor for the Li and B isotopic variations. → Most Li and B in rainwaters does not have a marine origin. → Finally, this work also adds to the potential for use of Li and B isotopes as environmental tracers. - Abstract: In the present work, the first results are reported for both Li and B isotope ratios in rainwater samples collected over a long time period (i.e. monthly rainfall events over 1 a) at a national scale (from coastal and inland locations). In addition, the stable isotopes of the water molecule (δD and δ 18 O) are also reported here for the same locations so that the Li and B isotope data can be discussed in the same context. The range of Li and B isotopic variations in these rainwaters were measured to enable the determination of the origin of these elements in rainwaters and the characterization of both the seasonal and spatio-temporal effects for δ 7 Li and δ 11 B signatures in rainwaters. Lithium and B concentrations are low in rainwater samples, ranging from 0.004 to 0.292 μmol/L and from 0.029 to 6.184 μmol/L, respectively. δ 7 Li and δ 11 B values in rainwaters also show a great range of variation between +3.2 per mille and +95.6 per mille and between -3.3 per mille and +40.6 per mille over a period of 1 a, respectively, clearly different from the signature of seawater. Seasonal effects (i.e. rainfall amount and month) are not the main factors controlling element concentrations and isotopic variations. δ 7 Li and δ 11 B values in rainwaters are clearly different from one site to another, indicating the variable contribution of sea salts in the rainwater depending on the sampling site (coastal vs. inland: also called the distance-from-the-coast-effect). This is well illustrated when wind direction data

  13. Modelling tree ring cellulose δ18O variations in two temperature-sensitive tree species from North and South America

    Directory of Open Access Journals (Sweden)

    A. Lavergne

    2017-11-01

    Full Text Available Oxygen isotopes in tree rings (δ18OTR are widely used to reconstruct past climates. However, the complexity of climatic and biological processes controlling isotopic fractionation is not yet fully understood. Here, we use the MAIDENiso model to decipher the variability in δ18OTR of two temperature-sensitive species of relevant palaeoclimatological interest (Picea mariana and Nothofagus pumilio and growing at cold high latitudes in North and South America. In this first modelling study on δ18OTR values in both northeastern Canada (53.86° N and western Argentina (41.10° S, we specifically aim at (1 evaluating the predictive skill of MAIDENiso to simulate δ18OTR values, (2 identifying the physical processes controlling δ18OTR by mechanistic modelling and (3 defining the origin of the temperature signal recorded in the two species. Although the linear regression models used here to predict daily δ18O of precipitation (δ18OP may need to be improved in the future, the resulting daily δ18OP values adequately reproduce observed (from weather stations and simulated (by global circulation model δ18OP series. The δ18OTR values of the two species are correctly simulated using the δ18OP estimation as MAIDENiso input, although some offset in mean δ18OTR levels is observed for the South American site. For both species, the variability in δ18OTR series is primarily linked to the effect of temperature on isotopic enrichment of the leaf water. We show that MAIDENiso is a powerful tool for investigating isotopic fractionation processes but that the lack of a denser isotope-enabled monitoring network recording oxygen fractionation in the soil–vegetation–atmosphere compartments limits our capacity to decipher the processes at play. This study proves that the eco-physiological modelling of δ18OTR values is necessary to interpret the recorded climate signal more reliably.

  14. Constraining the origin of the Messinian gypsum deposits using coupled measurement of δ^{18}O$/δD in gypsum hydration water and salinity of fluid inclusions

    Science.gov (United States)

    Evans, Nicholas P.; Gázquez, Fernando; McKenzie, Judith A.; Chapman, Hazel J.; Hodell, David A.

    2016-04-01

    We used oxygen and hydrogen isotopes of gypsum hydration water (GHW) coupled with salinity deduced from ice melting temperatures of primary fluid inclusions in the same samples (in tandem with 87Sr/86Sr, δ34S and other isotopic measurements) to determine the composition of the mother fluids that formed the gypsum deposits of the Messinian Salinity Crisis from shallow and intermediate-depth basins. Using this method, we constrain the origin of the Messinian Primary Lower Gypsum (PLG) of the Sorbas basin (Betic foreland) and both the Upper Gypsum (UG) and the Lower Gypsum of the Sicilian basin. We then compare these results to measurements made on UG recovered from the deep Ionian and Balearic basins drilled during DSDP Leg 42A. The evolution of GHW δ18O/δD vs. salinity is controlled by mixing processes between fresh and seawater, coupled with the degree of evaporation. Evaporation and subsequent precipitation of gypsum from fluids dominated by freshwater will result in a depressed 87Sr/86Sr values and different trajectory in δ18O/δD vs. salinity space compared to fluids dominated by seawater. The slopes of these regression equations help to define the end-members from which the fluid originated. For example, salinity estimates from PLG cycle 6 in the Sorbas basin range from 18 to 51ppt, and after correction for fractionation factors, estimated δ18O and δD values of the mother water are low (-2.6 meteoric water during gypsum deposition, while 87Sr/86Sr (0.708942 fall below those expected from the evaporation of seawater alone, the slope of the regression equation is similar to that of seawater evaporation. This implies that there is a change up-section from a dominantly marine environment in cycle 2 to a greater influence of meteoric water in cycle 6. The UG from the Sicilian basin display greater δ18O/δD values (2.9 meteoric water that subsequently underwent intense evaporation. This observation concurs with the low values of 87Sr/86Sr from the same UG

  15. Doxorubicin Loaded Chitosan-W18 O49 Hybrid Nanoparticles for Combined Photothermal-Chemotherapy.

    Science.gov (United States)

    Yuan, Shanmei; Hua, Jisong; Zhou, Yinyin; Ding, Yin; Hu, Yong

    2017-08-01

    Combined treatment is more effective than single treatment against most forms of cancer. In this work, doxorubicin loaded chitosan-W 18 O 49 nanoparticles combined with the photothermal therapy and chemotherapy are fabricated through the electrostatic interaction between positively charged chitosan and negatively charged W 18 O 49 nanoparticles. The in vitro and in vivo behaviors of these nanoparticles are examined by dynamic light scattering, transmission electron microscopy, cytotoxicity, near-infrared fluorescence imaging, and tumor growth inhibition experiment. These nanoparticles have a mean size around 110 nm and show a pH sensitive drug release behavior. After irradiation by the 980 nm laser, these nanoparticles show more pronounced cytotoxicity against HeLa cells than that of free doxorubicin or photothermal therapy alone. The in vivo experiments confirm that their antitumor ability is significantly improved, resulting in superior efficiency in impeding tumor growth and extension of the lifetime of mice. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Deuterium- and 18O-content in the cooling water of power station cooling towers

    International Nuclear Information System (INIS)

    Heimbach, H.; Dongmann, G.

    1976-09-01

    The 0-18/0-16 and D/H isotope ratios of water from two different cooling towers were determined by mass spectrometry. The observed isotope fractionation corresponds to that known from natural evaporation or transpiration processes: cooling tower I: delta(D) = 46.8 per thousand, delta( 18 O) = 7.6 per thousand cooling tower II: delta(D) = 33.9 per thousand delta( 18 O) = 5.7 per thousand Evaluation of simple compartment models of a cooling tower and a distillation device suggests that there exists some isotope discrimination within the open trickling unit of a cooling tower analogous to that in a rectification column. In a real cooling tower, however, this effect is compensated largely by the recycling of the cooling water, resulting only in a small enrichment of the heavy isotopes. This can be understood as the result of three partial effects: 1) a fractionation in the vapor pressure equilibrium, 2) a kinetic effect due to diffusion of the water vapor into a turbulent atmosphere, and 3) an exchange effect which is proportional to relative humidity. This low enrichment of the heavy isotope excludes the technical use of cooling towers as isotope separation devices. (orig.) [de

  17. Palaeohydrological implications in the Baltic area and its relation to the groundwater at Aespoe, south-eastern Sweden - A literature study

    Energy Technology Data Exchange (ETDEWEB)

    Wallin, B [Geokema AB, Lidingoe (Sweden)

    1995-03-01

    A literature study of different groundwaters in the circum Baltic region is presented in this work. The study is mainly focused on the isotopic signatures observed in different groundwaters in Sweden and Finland. Several saline groundwaters in the Baltic region at depth of 150 to 500m depth show stable ({delta}D, {delta}{sup 13}C, {delta}{sup 18}O) and radiogenic ({delta}{sup 87}Sr) isotope assembly which is suggestive of a marine origin. However, a discrepancy is sometimes observed between the stable as well as radiogenic isotopes of the intermediate groundwater, which suggest a mixture of fossil marine water and a post-glacial runoff of melt water. In order to explain this phenomenon, the initial setting in {delta}{sup 18}O may have been depleted due to large input of high latitude marine water or cold melt waters. A solution to the contradiction between the strontium ({delta}{sup 87}Sr) and stable isotope ({delta}D, {delta}{sup 13}C, {delta}{sup 18}O) signatures of the groundwater and of the calcite fracture fillings at Aespoe and other places is attained, if it is assumed that the strontium in Baltic Sea water has undergone a significant decrease in {delta}{sup 87}Sr since the last glaciation. A scenario can be constructed to suggest that the Baltic Sea during the initial stage of the Litorina sea (8000 to 5000 Y B.P.) contained strontium with much larger {delta}{sup 87}Sr values. Another explanation for the positive {delta}{sup 87}Sr values may be due to water/rock interaction between the groundwater and the abundant fracture clay minerals, which are observed at Aespoe. Typically most of the saline groundwaters occur both in Sweden and Finland below the highest marine shore line during the Holocene. Almost all inland groundwaters show a totally different pattern which is typically non marine, meteoric in origin. (Abstract Truncated)

  18. Similar speleothem δ18O signals indicating diverging climate variations in inland central Asia and monsoonal south Asia during the Holocene

    Science.gov (United States)

    Jin, Liya; Zhang, Xiaojian

    2017-04-01

    High-resolution and precisely dated speleothem oxygen isotope (δ18O) records from Asia have provided key evidence for past monsoonal changes. It is found that δ18O records of stalagmites from Kesang Cave (42°52'N, 81°45'E, Xinjiang, China) in inland central Asia were very similar to those from Qunf Cave (17°10'N, 54°18'E, southern Oman) in South Asia, shifting from light to heavy throughout the Holocene, which was regarded as a signal that strong Asian summer monsoon (ASM) may have intruded into the Kesang Cave site and/or adjacent areas in inland central Asia to produce heavy rainfall during the high insolation times (e.g. the early Holocene). However, this is in contrast to conclusions based on other Holocene proxy records and modeling simulations, showing a persistent wetting trend in arid central Asia during the Holocene with a dryer condition in the early Holocene and the wettest condition in the late Holocene. With an analysis of model-proxy data comparison, we revealed a possible physical mechanism responsible for the Holocene evolution of moisture/precipitation in Asian summer monsoon (ASM)-dominated regions and that in the inland central Asia. It is revealed that a recurrent circumglobal teleconnection (CGT) pattern in the summertime mid-latitude circulation of the Northern Hemisphere was closely related to the ASM and the climate of inland central Asia, acting as a bridge linking the ASM to insolation, high-latitude forcing (North Atlantic sea surface temperature (SST)), and low-latitude forcing (tropical Ocean SST). Also, the CGT influence speleothem δ18O values in South Asia via its effect on the amount of precipitation. In addition, the moisture source from the Indian Ocean is associated with relatively high δ18O values compared with that from the North Atlantic Ocean, leading to increased precipitation δ18O values. Hence, the CGT has probably been the key factor responsible for the in-phase relationship in speleothem δ18O values (Kesang Cave

  19. A stable isotope study of serpentinization in the Fengtien ophiolite, Taiwan

    Energy Technology Data Exchange (ETDEWEB)

    Tzen-Fu Yui; Hsueh-Wen Yeh (Univ. of Hawaii, Honolulu (USA)); Chihming Wang Lee (National Taiwan Univ. (Taiwan))

    1990-05-01

    Detailed H- and O-isotopic studies of serpentinites of Fengtien ophiolite have been made in order to enhance our knowledge on the process of serpentinization. Pseudomorphic lizardites have {delta}{sup 18}O = +3.6{per thousand} and {delta}D = {minus}48 to {minus}49{per thousand}; bladed-mat and foliated antigorites have {delta}{sup 18}O = +3.5 to +5.8{per thousand} and {delta}D = {minus}45 to {minus}69{per thousand}; slickensided antigorites have {delta}{sup 18}O = +4.1 to +4.9{per thousand} and {delta}D = {minus}46 to {minus}50{per thousand}; picrolites have {delta}{sup 18}O = +4.2 to +4.3{per thousand} and {delta}D = {minus}65 to {minus}67{per thousand}; and slickensided chrysotiles have {delta}{sup 18}O = +4.1 to +4.5{per thousand} and {delta}D = {minus}80{per thousand}. It is suggested that lizardite might have formed in an oceanic environment, whereas antigorite and chrysotile have formed in continental environments. These results depict complicated multiple serpentinization processes. Isotopic temperatures calculated using {delta}{sup 18}O values of coexisting fissure-filling minerals range from 325 to 370{degree}C, which are consistent with those derived from phase equilibria involving serpentines. The narrow range of {delta}{sup 18}O and wide range of {delta}D values for antigorite and chrysotile also demonstrate that water/rock ratios during these serpentinizations should not have been high. These Fengtien serpentines fall outside either of the continental domains described by Wenner and Taylor (1973, 1974); and fall within their oceanic domain. We suggest that the domains proposed by Wenner and Taylor (1973, 1974) should be extended and that the terms, especially the continental antigorite and the continental lizardite-chrysotile, should be purely occurrence-descriptive.

  20. Simulating dynamics of {delta}{sup 13}C of CO{sub 2} in the planetary boundary layer a boreal forest region: covariation between surface fluxes and atmospheric mixing

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Baozhang; Chen, Jing M. [Univ. of Toronto, ON (Canada). Dept. of Geography; Tans, Pieter P. [National Oceanic and Atmospheric Administration, Boulder, CO (United States). Earth System Research Lab.; Huang, Lin [Environment Canada, Toronto, ON (Canada). Atmospheric Science and Technology Directorate

    2006-11-15

    Stable isotopes of CO{sub 2} contain unique information on the biological and physical processes that exchange CO{sub 2} between terrestrial ecosystems and the atmosphere. Ecosystem exchange of carbon isotopes with the atmosphere is correlated diurnally and seasonally with the planetary boundary layer (PBL) dynamics. The strength of this kind of covariation affects the vertical gradient of {delta}{sup 13}C and thus the global {delta}{sup 13}C distribution pattern. We need to understand the various processes involved in transport/diffusion of carbon isotope ratio in the PBL and between the PBL and the biosphere and the troposphere. In this study, we employ a one-dimensional vertical diffusion/transport atmospheric model (VDS), coupled to an ecosystem isotope model (BEPS-EASS) to simulate dynamics of {sup 13}CO{sub 2} in the PBL over a boreal forest region in the vicinity of the Fraserdale (FRD) tower (49 deg 52 min 29.9 sec N, 81 deg 34 min 12.3 sec W) in northern Ontario, Canada. The data from intensive campaigns during the growing season in 1999 at this site are used for model validation in the surface layer. The model performance, overall, is satisfactory in simulating the measured data over the whole course of the growing season. We examine the interaction of the biosphere and the atmosphere through the PBL with respect to {delta}{sup 13}C on diurnal and seasonal scales. The simulated annual mean vertical gradient of {delta}{sup 13}C in the PBL in the vicinity of the FRD tower was about 0.025% in 1999. The {delta}{sup 13}C vertical gradient exhibited strong diurnal (29%) and seasonal (71%) variations that do not exactly mimic those of CO{sub 2}. Most of the vertical gradient (96.5% {+-}) resulted from covariation between ecosystem exchange of carbon isotopes and the PBL dynamics, while the rest (3.5%{+-}) was contributed by isotopic disequilibrium between respiration and photosynthesis. This disequilibrium effect on {delta}{sup 13}C of CO{sub 2} dynamics in PBL

  1. Simulating dynamics of (delta){sup 13}C of CO{sub 2} in the planetary boundary layer a boreal forest region: covariation between surface fluxes and atmospheric mixing

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Baozhang; Chen, Jing M. [Univ. of Toronto, ON (Canada). Dept. of Geography; Tans, Pieter P. [National Oceanic and Atmospheric Administration, Boulder, CO (United States). Earth System Research Lab.; Huang, Lin [Environment Canada, Toronto, ON (Canada). Atmospheric Science and Technology Directorate

    2006-11-15

    Stable isotopes of CO{sub 2} contain unique information on the biological and physical processes that exchange CO{sub 2} between terrestrial ecosystems and the atmosphere. Ecosystem exchange of carbon isotopes with the atmosphere is correlated diurnally and seasonally with the planetary boundary layer (PBL) dynamics. The strength of this kind of covariation affects the vertical gradient of (delta){sup 13}C and thus the global (delta){sup 13}C distribution pattern. We need to understand the various processes involved in transport/diffusion of carbon isotope ratio in the PBL and between the PBL and the biosphere and the troposphere. In this study, we employ a one-dimensional vertical diffusion/transport atmospheric model (VDS), coupled to an ecosystem isotope model (BEPS-EASS) to simulate dynamics of {sup 13}CO{sub 2} in the PBL over a boreal forest region in the vicinity of the Fraserdale (FRD) tower (49 deg 52 min 29.9 sec N, 81 deg 34 min 12.3 sec W) in northern Ontario, Canada. The data from intensive campaigns during the growing season in 1999 at this site are used for model validation in the surface layer. The model performance, overall, is satisfactory in simulating the measured data over the whole course of the growing season. We examine the interaction of the biosphere and the atmosphere through the PBL with respect to (delta){sup 13}C on diurnal and seasonal scales. The simulated annual mean vertical gradient of (delta){sup 13}C in the PBL in the vicinity of the FRD tower was about 0.025% in 1999. The (delta){sup 13}C vertical gradient exhibited strong diurnal (29%) and seasonal (71%) variations that do not exactly mimic those of CO{sub 2}. Most of the vertical gradient (96.5% {+-}) resulted from covariation between ecosystem exchange of carbon isotopes and the PBL dynamics, while the rest (3.5%{+-}) was contributed by isotopic disequilibrium between respiration and photosynthesis. This disequilibrium effect on (delta){sup 13}C of CO{sub 2} dynamics in PBL

  2. Measurement of δ18O, δ17O, and 17O-excess in Water by Off-Axis Integrated Cavity Output Spectroscopy and Isotope Ratio Mass Spectrometry

    Science.gov (United States)

    Berman, Elena S.F.; Levin, Naomi E.; Landais, Amaelle; Li, Shuning; Owano, Thomas

    2013-01-01

    Stable isotopes of water have long been used to improve understanding of the hydrological cycle, catchment hydrology, and polar climate. Recently, there has been increasing interest in measurement and use of the less-abundant 17O isotope in addition to 2H and 18O. Off-axis integrated cavity output spectroscopy (OA-ICOS) is demonstrated for accurate and precise measurements δ18O, δ17O, and 17O-excess in liquid water. OA-ICOS involves no sample conversion and has a small footprint, allowing measurements to be made by researchers collecting the samples. Repeated (514) high-throughput measurements of the international isotopic reference water standard GISP demonstrate the precision and accuracy of OA-ICOS: δ18OVSMOW-SLAP =−24.74 ± 0.07 ‰ (1σ) and δ17OVSMOW-SLAP = −13.12 ± 0.05 ‰ (1σ). For comparison, the IAEA value for δ18OVSMOW-SLAP is −24.76 ± 0.09 ‰ (1σ) and an average of previously reported values for δ17OVSMOW-SLAP is −13.12 ± 0.06 ‰ (1σ). Multiple (26) high-precision measurements of GISP provide a 17O-excessVSMOW-SLAP of 23 ± 10 per meg (1σ); an average of previously reported values for 17O-excessVSMOW-SLAP is 22 ± 11 per meg (1σ). For all these OA-ICOS measurements, precision can be further enhanced by additional averaging. OA-ICOS measurements were compared with two independent isotope ratio mass spectrometry (IRMS) laboratories and shown to have comparable accuracy and precision as the current fluorination-IRMS techniques in δ18O, δ17O, and 17O-excess. The ability to measure accurately δ18O, δ17O, and 17O-excess in liquid water inexpensively and without sample conversion is expected to increase vastly the application of δ17O and 17O-excess measurements for scientific understanding of the water cycle, atmospheric convection, and climate modeling among others. PMID:24032448

  3. Paleoenvironments, δ13C and δ18O signatures in the Neoproterozoic carbonates of the Comba Basin, Republic of Congo: Implications for regional correlations and Marinoan event

    Science.gov (United States)

    Préat, Alain; Delpomdor, Franck; Ackouala Mfere, Anna Perla; Callec, Yannick

    2018-01-01

    The Ediacaran Schisto-Calcaire Group is a ∼1300 m-thick succession belonging to the West Congo Supergroup in Central Africa. In the Comba Basin, it consists of three carbonate-dominated units defined as formations (SCI to SCIII) that are unconformably overlain by clastic deposits (Mpioka Group) interpreted as a molassic formation associated with the Panafrican Orogen. The underlying Upper Tillite and Cap Carbonate (SCIa) units, considered as markers of the Snowball Earth event were studied in three sections. We investigated the carbonates of the Schisto-Calcaire Group by defining new microfacies (MF1-MF7) and we performed C and O isotopic analyses in order to constraint the depositional and diagenetic events directly after the Marinoan interval. Stratigraphic variations of the stable isotopes are important in the series with lighter δ18O values (>1.5‰) than those of the Neoproterozoic ocean in the SCIc unit. According to regional stratigraphy a temperature effect can be dismissed and a freshwater surface layer is the origin of such negative δ18O values in this unit. The negative δ13C anomaly (-3.5‰ on average) of the Cap Carbonate is similarly to the δ18O values (-6.4‰ on average) in the range of the marine domain during postglacial sea level rise. The sample suite as a whole (SCII and SCIII formations) displays heavier δ18O and δ13C than those of the lower part (SCI unit) of the Schisto-Calcaire Group. The comparison with the Lower Congo (Democratic Republic of Congo) and Nyanga (Gabon) basins shows that the meteoric flushing in SCIc unit of the Schisto-Calcaire Group was regional and not local, and could be derived from a climatic evolution. Although an overall overprint is present, our isotopic relationships argue against overall diagenetic resetting of primary compositions and suggest that with careful examination combined with detailed petrographic analysis general depositional and diagenetic controls can be discerned in oxygen and carbon

  4. δ34S and δ18O of dissolved sulfate as biotic tracer of biogeochemical influences on arsenic mobilization in groundwater in the Hetao Plain, Inner Mongolia, China.

    Science.gov (United States)

    Li, M D; Wang, Y X; Li, P; Deng, Y M; Xie, X J

    2014-12-01

    Environmental isotopology of sulfur and oxygen of dissolved sulfate in groundwater was conducted in the Hetao Plain, northwestern China, aiming to better understand the processes controlling arsenic mobilization in arsenic-rich aqueous systems. A total of 22 groundwater samples were collected from domestic wells in the Hetao Plain. Arsenic concentrations ranged from 11.0 to 388 μg/L. The δ(34)S-SO4 and δ(18)O-SO4 values of dissolved sulfate covered a range from +1.48 to +22.4‰ and +8.17‰ to +14.8‰ in groundwater, respectively. The wide range of δ(34)S-SO4 values reflected either an input of different sources of sulfate, such as gypsum dissolution and fertilizer application, or a modification from biogeochemical process of bacterial sulfate reduction. The positive correlation between δ(34)S-SO4 and arsenic concentrations suggested that bacteria mediated processes played an important role in the mobilization of arsenic. The δ(18)O-SO4 values correlated non-linearly with δ(34)S-SO4, but within a relatively narrow range (+8.17 to +14.8‰), implying that complexities inherent in the sulfate-oxygen (O-SO4(2-)) origins, for instance, water-derived oxygen (O-H2O), molecular oxygen (O-O2) and isotope exchanging with dissolved oxides, are accounted for oxygen isotope composition of dissolved sulfate in groundwater in the Hetao Plain.

  5. The effect of carbonic anhydrase on the kinetics and equilibrium of the oxygen isotope exchange in the CO2-H2O system: Implications for δ18O vital effects in biogenic carbonates

    Science.gov (United States)

    Uchikawa, Joji; Zeebe, Richard E.

    2012-10-01

    Interpretations of the primary paleoceanographic information recorded in stable oxygen isotope values18O) of biogenic CaCO3 can be obscured by disequilibrium effects. CaCO3 is often depleted in 18O relative to the δ18O values expected for precipitation in thermodynamic equilibrium with ambient seawater as a result of vital effects. Vital effects in δ18O have been explained in terms of the influence of fluid pH on the overall δ18O of the sum of dissolved inorganic carbon (DIC) species (often referred to as "pH model") and in terms of 18O depletion as a result of the kinetic effects associated with CO2 hydration (CO2 + H2O ↔ H2CO3 ↔ HCO3- + H+) and CO2 hydroxylation (CO2 + OH- ↔ HCO3-) in the calcification sites (so-called "kinetic model"). This study addresses the potential role of an enzyme, carbonic anhydrase (CA), that catalyzes inter-conversion of CO2 and HCO3- in relation to the underlying mechanism of vital effects. We performed quantitative inorganic carbonate precipitation experiments in order to examine the changes in 18O equilibration rate as a function of CA concentration. Experiments were performed at pH 8.3 and 8.9. These pH values are comparable to the average surface ocean pH and elevated pH levels observed in the calcification sites of some coral and foraminiferal species, respectively. The rate of uncatalyzed 18O exchange in the CO2-H2O system is governed by the pH-dependent DIC speciation and the kinetic rate constant for CO2 hydration and hydroxylation, which can be summarized by a simple mathematical expression. The results from control experiments (no CA addition) are in agreement with this expression. The results from control experiments also suggest that the most recently published kinetic rate constant for CO2 hydroxylation has been overestimated. When CA is present, the 18O equilibration process is greatly enhanced at both pH levels due to the catalysis of CO2 hydration by the enzyme. For example, the time required for 18O

  6. Effect of N/Z in pre-scission neutron multiplicity for 16,18O+198Pt systems

    International Nuclear Information System (INIS)

    Sandal, R.; Behera, B.R.; Singh, V.; Kaur, M.; Kumar, A.; Singh, G.; Singh, K.P.; Sugathan, P.; Jhingan, A.; Golda, K.S.; Chatterjee, M.B.; Bhowmik, R.K.; Kalkal, S.; Siwal, D.; Goyel, S.; Mandal, S.; Prasad, E.; Sadhukhan, J.; Pal, S.; Mahta, K.; Saxena, A.

    2014-01-01

    This paper reports the summary of the experimental results of pre-scission neutron multiplicities from four compound nuclei, namely 210,212,214,216 Rn, and statistical model analysis of the corresponding data. The compound nuclei 210,212,214,216 Rn having N/Z values as 1.441, 1.465, 1.488, 1.511 respectively are populated through the 16,18 O+ 194,198 Pt reactions at excitation energies of 50, 61, 71.7 and 79 MeV. The measured neutron multiplicities are further analyzed with the statistical model of nuclear decay where fission hindrance due to nuclear dissipation is considered. The N/Z dependence of the dissipation strength at lowest excitation energy of the compound nuclei suggests shell closure effects. However, such effects are not observed at higher excitations where the variation of the dissipation strength with N/Z does not show any specific trend. The variation of N/Z in fission time scale is also shown. (authors)

  7. Influence of landscape features on variation of δ2H and δ18O in seasonal mountain snowpack

    Science.gov (United States)

    Kipnis, E. L.; Chapple, W.; Frank, J. M.; Traver, E.; Ewers, B. E.; Williams, D. G.

    2014-12-01

    Streamflow contributions from snowpack remain difficult to predict in snow dominated headwater catchments in the Rocky Mountains. There remains considerable uncertainty in how environmental change in mountain watersheds alter seasonal snowpack accumulation and development and how these relationships translate from gaged to ungaged catchments. Stable isotope analysis is a valuable tool for determining the contribution and changes of different source inputs to catchment water budgets. Stable isotope values in snowpack integrate source inputs and processes such as water vapor exchange, selective redistribution, and melt. For better understanding of how these physical processes vary at local and catchment scales, snowpack density, depth, snow water equivalence (SWE), δ2H and δ18O were examined at peak snowpack in spring 2013 and 2014 and at monthly time steps throughout the winter of 2013-2014. Distributed data and sample collection occurred between 2400 and 3300 m elevation across two pine beetle and spruce beetle impacted forest stands with variable canopy cover in the Libby Creek and Nash Fork Little Laramie River basins, Medicine Bow Range, Wyoming. Peak snowpack within these watersheds was 10% below historic average in 2013 and 50% above average in 2014 (NRCS Snotel data). Even with these contrasting peak snowpack patterns, elevation described less than 40% of the spatial variation of snow water equivalents (SWE) across the watersheds for both seasons. Hydrogen and oxygen isotope ratio values of snowpack sampled monthly in 2014 revealed early season separation from the local meteoric water line, suggesting some kinetic isotope effects. However, isotope ratio values at peak snowpack in 2013 reflected no such signal at any sampling location. The influence of landscape position and canopy cover will be modeled to detect and scale spatial and temporal changes in SWE and stable isotope composition of snowpack. Such an approach will provide increased understanding of

  8. The First Detailed 2H and 18O Isoscapes of Freshwater in Scotland

    Science.gov (United States)

    Meier-Augenstein, W.; Hoogewerff, J.; Kemp, H. F.; Frew, D.

    2012-04-01

    Scotland's freshwater lochs and reservoirs provide a vital resource for sustaining biodiversity, agriculture, food production as well as for human consumption. Regular monitoring of freshwater quality by the Scottish Environmental Protection Agency (SEPA) fulfils the legislative requirements but new scientific methods involving stable isotope analysis present an opportunity for delivering on current and nascent government policies [1] and gaining a greater understanding of Scottish waters and their importance in the context of climate change, environmental sustainability and the aforementioned functions. In brief, 2H and 18O isoscapes of Scottish freshwater could be used to support fundamental and applied research in: • Climate change - These first ever isoscapes will provide a baseline against which future environmental impact can be assessed due to changes in the characteristic isotope composition of freshwater lochs and reservoirs. • Scottish branding - Location specific stable isotope signatures of Scottish freshwater have the potential to be used as a tool for provenancing and thus protecting premium Scottish produce such as Scottish beef, Scottish berries and Scottish Whisky. During 2011, freshwater samples were collected with the support of SEPA from more than 80 freshwater lochs and reservoirs across Scotland. Here we present the result of the 2H and 18O stable isotope analyses of these water samples together with the first isoscapes generated based on these data. [1] Adaptation Framework - Adapting Our Ways: Managing Scotland's Climate Risk (2009): Scotland's Biodiversity: It's in Your Hands - A strategy for the conservation and enhancement of biodiversity in Scotland (2005); Recipe For Success - Scotland's National Food and Drink Policy (2009); Scottish Planning Policy Environmental Report (2009); Scottish Planning Policy (SPP) 15 Planning for Rural Development (2005); National Planning Policy Guideline (NPPG) 14: Natural Heritage (1999).

  9. Historical droughts in northern Vietnam captured by variability in speleothem δ18O

    Science.gov (United States)

    Hardt, B. F.; McGee, D.; Burns, S. J.; Hieu, N.; Hieu, D. T.

    2015-12-01

    Speleothem records overlapping with the historical period offer valuable comparisons of documentary evidence with speleothem proxy data. These records provide opportunities to 'ground-truth' the paleo-record, fill in gaps in the historical record, and more confidently extent the paleo-record into deeper time. Here we present isotopic results from a stalagmite collected in northern Vietnam spanning 1200 to 1950 CE, a period with a rich historical record in Vietnam. This sample adds significantly to the relatively sparse paleoclimate record from Southeast Asia. The record includes several multi-decadal positive excursions of ≥1 per mille in calcite δ18O. A preliminary age model, based on six U/Th ages, suggests possible correspondence to noted droughts from the historical record, including the Angkor Droughts, the Ming Dynasty Drought, the Strange Parallels Drought, and the Victorian Holocaust Drought. As modeling studies indicate a strong correlation between rainfall δ18O and both the intensity of summer monsoon winds and summer rainfall over northern Vietnam (e.g., Liu et al., 2014), these excursions are consistent with a decrease in regional precipitation. The Vietnam record shows an overall negative trend during the Little Ice Age. The study site is located well south of the westerly wind belt, ruling out a shift between monsoonal and mid-latitude circulation systems as a likely explanation for the northern Vietnam record. We explore the correspondence between our record and other proxy data from Southeast Asia and suggest possible implications of the differences between Vietnamese and Chinese speleothem records during the Little Ice Age. References cited: Liu Z., Wen X., Brady E. C., Otto-Bliesner B., Yu G., Lu H., Cheng H., Wang Y., Zheng W., Ding Y., Edwards R. L., Cheng J., Liu W. and Yang H. (2014) Chinese cave records and the East Asia Summer Monsoon. Quaternary Science Reviews 83, 115-128.

  10. New tool for getting data on the field for paleoclimate and paleoceanography data based on isotope 13C and 18O measurements

    Science.gov (United States)

    Mandic, M.; Stöbener, N.; Smajgl, D.

    2017-12-01

    For many decades different instrumental methods involving generations of the isotope ratio mass spectrometers with different periphery units for sample preparation, have provided scientifically required high precision, and high throughput of samples for varies application - from geological and hydrological to food and forensic. With this work we introduce automated measurement of δ13C and δ18O from solid carbonate samples, DIC and δ18O of water. We have demonstrated usage of a Thermo Scientific™ Delta Ray™ IRIS with URI Connect on certified reference materials and confirmed the high achievable accuracy and a precision better then analysis on the Delta Ray IRIS with URI Connect is similar to the previously mentioned Gas Bench II methods. Samples are put into vials and phosphoric acid is added. The resulting sample-acid chemical reaction releases CO2 gas, which is then introduced into the Delta Ray IRIS via the Variable Volume. Three international standards of carbonate materials (NBS-18, NBS-19 and IAEA-CO-1) were analyzed. NBS-18 and NBS-19 were used as standards for calibration, and IAEA-CO-1 was treated as unknown. For water sample analysis equilibration method with 1% of CO2 in dry air was used. Test measurements and conformation of precision and accuracy of method determination δ18O in water samples were done with three lab standards, namely ANST, OCEAN 2 and HBW. All laboratory standards were previously calibrated with international reference material VSMOW2 and SLAP2 to assure accuracy of the isotopic values. The Principle of Identical Treatment was applied in sample and standard preparation, in measurement procedure, as well as in the evaluation of the results.

  11. Variations in the D/H and 18O/16O ratios in cellulose extracted from a peat bog core

    International Nuclear Information System (INIS)

    Brenninkmeijer, C.A.M.; Mook, W.G.; Geel, B. van

    1982-01-01

    A peat core from a raised bog covering the period 3100 to 2400 14 C years B.P. has been analysed for D/H and 18 O/ 16 O ratios. These analyses were applied to cellulose, extracted from 56 successive layers of 1 cm thickness. D/H ratios were determined for the carbon bonded hydrogen; 18 O/ 16 O analyses were performed by applying a new method. For the interpretation of the results obtained on peat, the isotopic ratios of 11 living bog plant species were measured, showing a relatively large scatter. Most pronounced is a depletion in D of about 25per mille and in 18 O of about 5per mille of the Sphagnum mosses relative to the vascular bog plants. This different isotopic composition is reflected by the deltaD and delta 18 O records of the peat core, because the abundance of the remains of non-vascular plants is variable. If this effect is taken account of, the remaining deltaD variations appear to be too large to be attributed to variations in the isotopic compositions of precipitation. As palaeoclimatic indicators the D/H and 18 O/ 16 O ratio qualitatively agree with the pollen analytical evidence for the climatic deterioration of the Subboreal-Subatlantic transition. (orig.)

  12. Correlation between δ18O in precipitation and surface air temperature on different time-scale in China

    International Nuclear Information System (INIS)

    Zhang Lin; Chen Zongyu; Nie Zhenlong; Liu Fuliang; Jia Yankun; Zhang Xiangyang

    2008-01-01

    The relation between isotopic compositions of precipitation and surface air temperature provides a unique tool for paleoclimate studies, among which the relation between long term changes in δ 18 O of precipitation and surface air temperature at different stations or in a given location seems to be the most appropriate to paleoclimatic reconstructions. Analysis was conducted on monthly and annual mean δ 18 O content of precipitation and surface air temperature at spatial and fixed locations by using the data of China (1985-2002) in Global Network of Isotopes in Precipitation (GNIP) Database. This study shows that there is a positive correlation between δ 18 O of precipitation and surface air temperature for stations located in north of 34 degree-36 degree N latitudes. The seasonal δ 18 O-temperature gradient derived from the monthly data of 12 stations in northern China is about 0.034% degree C -1 . The δ 18 O-temperature gradient, however, derived from the long term annual mean data of 13 stations, is about 0.052% degree C -1 , which is substantially larger than the seasonal gradient. (authors)

  13. Use of the isotope flux ratio approach to investigate the C18O16O and 13CO2 exchange near the floor of a temperate deciduous forest

    Directory of Open Access Journals (Sweden)

    P. Bartlett

    2012-07-01

    Full Text Available Stable isotopologues of CO2, such as 13CO2 and C18OO, have been used to study the CO2 exchange between land and atmosphere. The advent of new measuring techniques has allowed near-continuous measurements of stable isotopes in the air. These measurements can be used with micrometeorological techniques, providing new tools to investigate the isotope exchange in ecosystems. The objectives of this study were to evaluate the use of the isotope flux ratio method (IFR near the forest floor of a temperate deciduous forest and to study the temporal dynamics of δ18O of CO2 flux near the forest floor by comparing IFR estimates with estimates of δ18O of net soil CO2 flux provided by an analytical model. Mixing ratios of 12C16O2, 13CO2 and C16O18O were measured within and above a temperate deciduous forest, using the tunable diode laser spectroscopy technique. The half-hourly compositions of the CO2 flux near the forest floor (δ13CF and δ18OF were calculated by IFR and compared with estimates provided by a modified Keeling plot technique (mKP and by a Lagrangian dispersion analysis (WT analysis. The mKP and IFR δ18OF estimates showed good agreement (slope = 1.03 and correlation, R2 = 0.80. The δ13CF estimates from the two methods varied in a narrow range of −32.7 and −23‰; the mean (± SE mKP and IFR δ13CF values were −27.5‰ (±0.2 and −27.3‰ (±0.1, respectively, and were statistically identical (p>0.05. WT analysis and IFR δ18OF estimates showed better correlation (R2 = 0.37 when only turbulent periods (u*>0.6 m s−1 were included in the analysis. The large amount of data captured (~95 % of half-hour periods evaluated for the IFR in comparison with mKP (27 % shows that the former provides new opportunities for studying δ18OF dynamics within forest canopies. Values of δ18OF showed large temporal variation, with values ranging from −31.4‰ (DOY 208 to −11.2‰ (DOY 221. Precipitation events caused substantial variation (~8

  14. Application of stable isotopes (δ{sup 34}S-SO{sub 4}, δ{sup 18}O-SO{sub 4,} δ{sup 15}N-NO{sub 3}, δ{sup 18}O-NO{sub 3}) to determine natural background and contamination sources in the Guadalhorce River Basin (southern Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Urresti-Estala, Begoña, E-mail: b.urresti@uma.es [Universidad de Málaga, Facultad de Ciencias, Grupo de Geodinámica Externa, Campus de Teatinos s/n, 29071 Málaga (Spain); Vadillo-Pérez, Iñaki; Jiménez-Gavilán, Pablo [Universidad de Málaga, Facultad de Ciencias, Grupo de Geodinámica Externa, Campus de Teatinos s/n, 29071 Málaga (Spain); Soler, Albert [Grup de Mineralogia Aplicada i Medi Ambient, Fac. Geologia, Universitat de Barcelona, Barcelona (Spain); Sánchez-García, Damián; Carrasco-Cantos, Francisco [Universidad de Málaga, Facultad de Ciencias, Grupo de Geodinámica Externa, Campus de Teatinos s/n, 29071 Málaga (Spain)

    2015-02-15

    The integrated use of isotopes (δ{sup 34}S-SO{sub 4}, δ{sup 18}O-SO{sub 4,} δ{sup 15}N-NO{sub 3}, δ{sup 18}O-NO{sub 3}), taking into account existing hydrogeological knowledge of the study area (mainly hydrochemical), was applied in the Guadalhorce River Basin (southern Spain) to characterise SO{sub 4}{sup 2−} and NO{sub 3}{sup −} sources, and to quantify natural background levels (NBLs) in groundwater bodies. According to Water Framework Directive 2000/60/EC and, more recently, Groundwater Directive 2006/118/EC, it is important to determine NBLs, as their correct assessment is the first, essential step to characterising groundwater bodies, establishing threshold values, assessing chemical status and identifying trends in pollutant concentrations. In many cases, NBLs are high for some parameters and types of groundwater, making it difficult to distinguish clearly between factors of natural or human origin. The main advantages of using stable isotopes in a complex area like the Guadalhorce River Basin that exhibits widely varying hydrogeological and hydrochemical conditions and longstanding anthropogenic influences (mainly agriculture, but also many others) is accurate determination of pollution sources and precise quantification of NBLs. Since chemical analyses only provides the concentration of pollutants in water and not the source, three isotopic sampling campaigns for sulphates (δ{sup 34}S-SO{sub 4}, δ{sup 18}O-SO{sub 4}) were carried out, in 2006, 2007 and 2012, and another one was conducted for nitrates (δ{sup 15}N-NO{sub 3}, δ{sup 18}O-NO{sub 3}), in 2009, in groundwater bodies in order to trace the origins of each pollutant. The present study identified different pollution sources of dissolved NO{sub 3}{sup −} in groundwater using an isotopic composition and quantified the percentage of natural (lithology, chemical and biological processes) and anthropogenic (fertilisers, manure and sewage) SO{sub 4}{sup 2−} and matched a concentration

  15. Reconstructing the δ(18) O of atmospheric water vapour via the CAM epiphyte Tillandsia usneoides: seasonal controls on δ(18) O in the field and large-scale reconstruction of δ(18) Oa.

    Science.gov (United States)

    Helliker, Brent R

    2014-03-01

    Using both oxygen isotope ratios of leaf water (δ(18) OL ) and cellulose (δ(18) OC ) of Tillandsia usneoides in situ, this paper examined how short- and long-term responses to environmental variation and model parameterization affected the reconstruction of the atmospheric water vapour (δ(18) Oa ). During sample-intensive field campaigns, predictions of δ(18) OL matched observations well using a non-steady-state model, but the model required data-rich parameterization. Predictions from the more easily parameterized maximum enrichment model (δ(18) OL-M ) matched observed δ(18) OL and observed δ(18) Oa when leaf water turnover was less than 3.5 d. Using the δ(18) OL-M model and weekly samples of δ(18) OL across two growing seasons in Florida, USA, reconstructed δ(18) Oa was -12.6 ± 0.3‰. This is compared with δ(18) Oa of -12.4 ± 0.2‰ resolved from the growing-season-weighted δ(18) OC . Both of these values were similar to δ(18) Oa in equilibrium with precipitation, -12.9‰. δ(18) Oa was also reconstructed through a large-scale transect with δ(18) OL and the growing-season-integrated δ(18) OC across the southeastern United States. There was considerable large-scale variation, but there was regional, weather-induced coherence in δ(18) Oa when using δ(18) OL . The reconstruction of δ(18) Oa with δ(18) OC generally supported the assumption of δ(18) Oa being in equilibrium with precipitation δ(18) O (δ(18) Oppt ), but the pool of δ(18) Oppt with which δ(18) Oa was in equilibrium - growing season versus annual δ(18) Oppt - changed with latitude. © 2013 John Wiley & Sons Ltd.

  16. Latest Paleocene benthic extinction event on the southern Tethyan shelf (Egypt): Foraminiferal stable isotopic (δ13C, δ18O) records

    Science.gov (United States)

    Schmitz, B.; Speijer, R. P.; Aubry, M.-P.

    1996-04-01

    The dramatic global extinction of 35% 50% of benthic foraminifera species in the deep sea in the latest Paleocene and associated negative excursions in δ13C and δ18O may be related to spreading of warm, saline bottom water from subtropical Tethyan shallow regions over the sea floor worldwide. Our study of neritic sections in Egypt shows that in the southern shallow Tethys, a prominent long-term change in bottom-water chemistry, sedimentation, and benthic foraminifera fauna was initiated at the time when the deep-sea benthic extinction event (BEE) took place. Bottom-water δ13C values on the Tethyan shelf show a sudden 3.0‰ negative shift at this event; however, contrary to the deep sea, in which the δ13C excursion was of short duration, Tethyan δ13C values did not fully return to preboundary values, but remained depressed by ˜1.5‰ for at least 1 m.y. The δ13C values at the Egyptian shelf during the BEE are much lower than would be expected if this was a source region for global deep water. The δ18O values indicate no significant change in bottom-water salinity or temperature at the BEE. The long-lasting environmental changes that began on the Egyptian shelf at the BEE may be related to, for example, gateway reorganization along the Tethyan seaway. Paleogeographic changes possibly also triggered a change in the loci of global deep-water formation; however, these loci must be sought in another part of the Tethys.

  17. Coherent response of the Indo-African boreal summer monsoon to Pacific SST captured in Ethiopian rain δ18O

    Science.gov (United States)

    Madhavan, M.; Palliyil, L. R.; Ramesh, R.

    2017-12-01

    Pacific Sea Surface Temperature (SST) plays an important role in the inter-annual to inter-decadal variability of boreal monsoons. We identified a common mode of inter annual variability in the Indian and African boreal summer monsoon (June to September) rainfalls, which is linked to Pacific SSTs, using Empirical Orthogonal Function (EOF) analysis. Temporal coefficients (Principle component: PC1) of the leading mode of variability (EOF-1) is well correlated with the Indian summer monsoon rainfall and Sahel rainfall. About forty year long monthly observations of δ18O (and δD) at Addis Ababa, Ethiopia show a strong association with PC1 (r=0.69 for δ18O and r=0.75 for δD). Analysis of SST, sea level pressure and lower tropospheric winds suggest that 18O depletion in Ethiopian rainfall (and wet phases of PC1) is associated with cooler eastern tropical Pacific and warmer western Pacific and strengthening of Pacific subtropical high in both the hemispheres. Associated changes in the trade winds cause enhanced westerly moisture transport into the Indian subcontinent and northern Africa and cause enhanced rainfall. The intrusion of Atlantic westerly component of moisture transport at Addis Ababa during wet phases of PC1 is clearly recorded in δ18O of rain. We also observe the same common mode of variability (EOF1) of Indo-African boreal summer monsoon rain on decadal time scales. A 100 year long δ18O record of actively growing speleothem from the Mechara cave, Ethiopia, matches very well with the PC1 on the decadal time scale. This highlights the potential of speleothem δ18O and leaf wax δD from Ethiopia to investigate the natural variability and teleconnections of Indo-African boreal monsoon.

  18. Synthesis of tungsten oxide (W{sub 18}O{sub 49}) nanosheets utilizing EDTA salt by microwave irradiation method

    Energy Technology Data Exchange (ETDEWEB)

    Hariharan, V.; Parthibavarman, M. [Centre for Nanoscience and Technology, Department of Physics, Periyar University, Salem 636 011, Tamilnadu (India); Sekar, C., E-mail: Sekar2025@gmail.com [Centre for Nanoscience and Technology, Department of Physics, Periyar University, Salem 636 011, Tamilnadu (India); Department of Bioelectronics and Biosensors, Alagappa University, Karaikudi 630 003, Tamilnadu (India)

    2011-04-07

    Research highlights: > We have synthesized tungsten oxide (WO{sub 3-{delta}}) nanoparticles by microwave irradiation method for the first time using EDTA as surface modulator. The variation in stoichiometric oxygen content of the annealed samples clearly indicates the role of EDTA in reaction medium. The variation in oxygen content also modified the transparency of the end product confirming the change in optical conductivity. - Abstract: We report the synthesis of crystalline W{sub 18}O{sub 49} with nanosheet like morphology by low cost microwave irradiation method without employing hydrothermal process for the first time. Initially, WO{sub 3}.H{sub 2}O was synthesized using ethylenediaminetetraacetic acid (EDTA) as surface modulator. The product was annealed at 600 {sup o}C for 6 h in ambient atmosphere in order to obtain anhydrous tungsten oxide W{sub 18}O{sub 49}. Powder X-ray diffraction results confirmed the as prepared WO{sub 3}.H{sub 2}O to be orthorhombic and W{sub 18}O{sub 49} to be monoclinic phase, respectively. Transmission electron micrographs (TEM) revealed that the W{sub 18}O{sub 49} nanosheets have the average dimensions of the order of 250 nm in length and around 150 nm in width. UV-visible diffusion reflectance spectroscopic (DRS) studies revealed the band gap energies to be 3.28 and 3.47 eV for WO{sub 3}.H{sub 2}O and W{sub 18}O{sub 49} samples, respectively. The growth mechanism of two dimensional W{sub 18}O{sub 49} nanosheets is discussed.

  19. Use of Isotope Ratio Mass Spectrometry (IRMS) Determination ((18)O/(16)O) to Assess the Local Origin of Fish and Asparagus in Western Switzerland.

    Science.gov (United States)

    Rossier, Joël S; Maury, Valérie; de Voogd, Blaise; Pfammatter, Elmar

    2014-10-01

    Here we present the use of isotope ratio mass spectrometry (IRMS) for the detection of mislabelling of food produced in Switzerland. The system is based on the analysis of the oxygen isotope distribution in water (δ(18)O). Depending on the location on the earth, lake or groundwater has a specific isotopic distribution, which can serve as a fingerprint in order to verify whether a product has grown by means of the corresponding water. This report presents specifically the IRMS technique and the results obtained in the origin detection of fish grown in selected Swiss lakes as well as asparagus grown in Valais ground. Strengths and limitations of the method are presented for both cited products; on one hand, the technique is relatively universal for any product which contains significant water but on the other hand, it necessitates a rather heavy workload to build up a database of water δ(18)O values of products of different origins. This analytical tool is part of the concept of combating fraud currently in use in Switzerland.

  20. Oxygen 18 concentration profile measurements near the surface by 18O(p,α)15N resonance reaction

    International Nuclear Information System (INIS)

    Amsel, G.; David, D.

    1975-01-01

    The method of spectrum reduction in nuclear reaction microanalysis does not allow to obtain depth resolutions better than the order of 2000A. Resolutions of the order of 200A may be obtained by using the narrow resonance technique, when applied to thin films. The latter technique was extended to thick targets, with deep concentration profiles presenting a sharp gradient near the surface. This method is presented and illustrated by the study of 18 O profiles in oxygen diffusion measurements in growing ZrO 2 , using the 629keV resonance of the reaction 18 O(p,α) 15 N [fr

  1. Separating Long-Lived Metal Ions from {sup 18}F During H{sub 2} {sup 18}O Recovery

    Energy Technology Data Exchange (ETDEWEB)

    Schueller, Michael John; Alexoff, David L.; Schlyer, David James [Medical Department, Brookhaven National Laboratory, 57 Cornell Street, Upton NY 11973 (United States)

    2009-07-01

    Cyclotron targets for the production of [{sup 18}F]fluoride usually use a thin metal window to contain the {sup 18}O enriched water during irradiation. This window is activated by the proton beam, and undesired radioisotopes can enter the target water. A pre-packaged strong anion exchange resin is commonly used for [{sup 18}O]-water recovery. A two-column method has been developed which delivers >95% of the [18F]fluoride for radiosynthesis while rejecting >99.9% of the contaminants. (author)

  2. Reconciling the sea level record of the last deglaciation with the δ18O spectra from deep sea cores

    International Nuclear Information System (INIS)

    Bard, Edouard; Columbia Univ., Palisades, NY; Arnold, Maurice; Duplessy, J.-C.

    1991-01-01

    In this paper we use the oxygen isotope record as a transient tracer to study palaeoceanography during the last deglaciation. By using 14 C and 18 O data obtained on four deep sea sediment cores, we show the presence of a measurable lag between the deglacial δ 18 O signal observed in the deep Atlantic and the deep Indo-Pacific oceans. Our study confirms that the major meltwater discharge occurred via the North Atlantic and that the thermohaline circulation was operating during the deglacial transition. (Author)

  3. Exploring the 13CO/C18O abundance ratio towards Galactic young stellar objects and HII regions

    Science.gov (United States)

    Areal, M. B.; Paron, S.; Celis Peña, M.; Ortega, M. E.

    2018-05-01

    Aims: Determining molecular abundance ratios is important not only for the study of Galactic chemistry, but also because they are useful to estimate physical parameters in a large variety of interstellar medium environments. One of the most important molecules for tracing the molecular gas in the interstellar medium is CO, and the 13CO/C18O abundance ratio is usually used to estimate molecular masses and densities of regions with moderate to high densities. Nowadays isotope ratios are in general indirectly derived from elemental abundances ratios. We present the first 13CO/C18O abundance ratio study performed from CO isotope observations towards a large sample of Galactic sources of different natures at different locations. Methods: To study the 13CO/C18O abundance ratio, we used 12CO J = 3 - 2 data obtained from the CO High-Resolution Survey, 13CO and C18O J = 3 - 2 data from the 13CO/C18O (J = 3 - 2) Heterodyne Inner Milky Way Plane Survey, and some complementary data extracted from the James Clerk Maxwell Telescope database. We analyzed a sample of 198 sources composed of young stellar objects (YSOs), and HII and diffuse HII regions as catalogued in the Red MSX Source Survey in 27.°5 ≤ l ≤ 46.°5 and |b|0.°5. Results: Most of the analyzed sources are located in the galactocentric distance range 4.0-6.5 kpc. We found that YSOs have, on average, lower 13CO/C18O abundance ratios than HII and diffuse HII regions. Taking into account that the gas associated with YSOs should be less affected by the radiation than in the case of the others sources, selective far-UV photodissociation of C18O is confirmed. The 13CO/C18O abundance ratios obtained in this work are systematically lower than those predicted from the known elemental abundance relations. These results will be useful in future studies of molecular gas related to YSOs and HII regions based on the observation of these isotopes.

  4. 2H NMR and 13C-IRMS analyses of acetic acid from vinegar, 18O-IRMS analysis of water in vinegar: international collaborative study report.

    Science.gov (United States)

    Thomas, Freddy; Jamin, Eric

    2009-09-01

    An international collaborative study of isotopic methods applied to control the authenticity of vinegar was organized in order to support the recognition of these procedures as official methods. The determination of the 2H/1H ratio of the methyl site of acetic acid by SNIF-NMR (site-specific natural isotopic fractionation-nuclear magnetic resonance) and the determination of the 13C/12C ratio, by IRMS (isotope ratio mass spectrometry) provide complementary information to characterize the botanical origin of acetic acid and to detect adulterations of vinegar using synthetic acetic acid. Both methods use the same initial steps to recover pure acetic acid from vinegar. In the case of wine vinegar, the determination of the 18O/16O ratio of water by IRMS allows to differentiate wine vinegar from vinegars made from dried grapes. The same set of vinegar samples was used to validate these three determinations. The precision parameters of the method for measuring delta13C (carbon isotopic deviation) were found to be similar to the values previously obtained for similar methods applied to wine ethanol or sugars extracted from fruit juices: the average repeatability (r) was 0.45 per thousand, and the average reproducibility (R) was 0.91 per thousand. As expected from previous in-house study of the uncertainties, the precision parameters of the method for measuring the 2H/1H ratio of the methyl site were found to be slightly higher than the values previously obtained for similar methods applied to wine ethanol or fermentation ethanol in fruit juices: the average repeatability was 1.34 ppm, and the average reproducibility was 1.62 ppm. This precision is still significantly smaller than the differences between various acetic acid sources (delta13C and delta18O) and allows a satisfactory discrimination of vinegar types. The precision parameters of the method for measuring delta18O were found to be similar to the values previously obtained for other methods applied to wine and

  5. 2H NMR and 13C-IRMS analyses of acetic acid from vinegar, 18O-IRMS analysis of water in vinegar: International collaborative study report

    International Nuclear Information System (INIS)

    Thomas, Freddy; Jamin, Eric

    2009-01-01

    An international collaborative study of isotopic methods applied to control the authenticity of vinegar was organized in order to support the recognition of these procedures as official methods. The determination of the 2 H/ 1 H ratio of the methyl site of acetic acid by SNIF-NMR (site-specific natural isotopic fractionation-nuclear magnetic resonance) and the determination of the 13 C/ 12 C ratio, by IRMS (isotope ratio mass spectrometry) provide complementary information to characterize the botanical origin of acetic acid and to detect adulterations of vinegar using synthetic acetic acid. Both methods use the same initial steps to recover pure acetic acid from vinegar. In the case of wine vinegar, the determination of the 18 O/ 16 O ratio of water by IRMS allows to differentiate wine vinegar from vinegars made from dried grapes. The same set of vinegar samples was used to validate these three determinations. The precision parameters of the method for measuring δ 13 C (carbon isotopic deviation) were found to be similar to the values previously obtained for similar methods applied to wine ethanol or sugars extracted from fruit juices: the average repeatability (r) was 0.45 per mille , and the average reproducibility (R) was 0.91 per mille . As expected from previous in-house study of the uncertainties, the precision parameters of the method for measuring the 2 H/ 1 H ratio of the methyl site were found to be slightly higher than the values previously obtained for similar methods applied to wine ethanol or fermentation ethanol in fruit juices: the average repeatability was 1.34 ppm, and the average reproducibility was 1.62 ppm. This precision is still significantly smaller than the differences between various acetic acid sources (δ 13 C and δ 18 O) and allows a satisfactory discrimination of vinegar types. The precision parameters of the method for measuring δ 18 O were found to be similar to the values previously obtained for other methods applied to wine and

  6. Long-Term Precipitation Isotope Ratios (δ18O, δ2H, d-excess) in the Northeast US Reflect Atlantic Ocean Warming and Shifts in Moisture Sources

    Science.gov (United States)

    Puntsag, T.; Welker, J. M.; Mitchell, M. J.; Klein, E. S.; Campbell, J. L.; Likens, G.

    2014-12-01

    The global water cycle is exhibiting dramatic changes as global temperatures increase resulting in increases in: drought extremes, flooding, alterations in storm track patterns with protracted winter storms, and greater precipitation variability. The mechanisms driving these changes can be difficult to assess, but the spatial and temporal patterns of precipitation water isotopes (δ18O, δ2H, d-excess) provide a means to help understand these water cycle changes. However, extended temporal records of isotope ratios in precipitation are infrequent, especially in the US. In our study we analyzed precipitation isotope ratio data from the Hubbard Brook Experimental Forest in New Hampshire that has the longest US precipitation isotope record, to determine: 1) the monthly composited averages and trends from 1967 to 2012 (45 years); ; 2) the relationships between abiotic properties such as local temperatures, precipitation type, storm tracks and isotope ratio changes; and 3) the influence of regional shifts in moisture sources and/or changes in N Atlantic Ocean water conditions on isotope values. The seasonal variability of Hubbard Brook precipitation isotope ratios is consistent with other studies, as average δ18O values are ~ -15‰ in January and ~ -5 ‰ in July. However, over the 45 year record there is a depletion trend in the δ 18O values (becoming isotopically lighter with a greater proportion of 16O), which coupled with less change in δ 2H leads to increases in d-excess values from ~ -10‰ around 1970 to greater than 10‰ in 2009. These changes occurred during a period of warming as opposed to cooling local temperatures indicating other processes besides temperature are controlling long-term water isotope traits in this region. We have evidence that these changes in precipitation isotope traits are controlled in large part by an increases in moisture being sourced from a warming N Atlantic Ocean that is providing evaporated, isotopically

  7. Simultaneous Measurement of Nitrogen and Oxygen Isotopes of Nitrate to Evaluate Nitrate Sources and Processes in Catchments

    Energy Technology Data Exchange (ETDEWEB)

    Ohte, Nobuhito [Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo (Japan); Nagata, Toshi; Tayasu, Ichiro [Center for Ecological Research, Kyoto University, Ohtsu (Japan); Kyozu, Ayato; Yoshimizu, Chikage [CREST, Japan Science and Technology Agency, Center for Ecological Research, Kyoto University, Ohtsu (Japan); Osaka, Ken' ichi [Carbon and Nutrient Cycles Division, National Institute for Agro-Environmental Sciences, Tsukuba, (Japan)

    2013-05-15

    We review studies on applied isotope analytical techniques for identifying sources and transformations of river nitrate (NO{sub 3}{sup -}) to examine the influences of water pollution, excess nutrient (nitrogen) loads and ecosystem disturbances in river systems. We also discuss the current status and future perspectives of the application of NO{sub 3}{sup -} isotope measurements to the assessment of river nutrients. Our review shows that in recent years simultaneous measurements of nitrogen and oxygen isotopes ({delta}{sup 15}N and {delta}{sup 18}O) of NO{sub 3}{sup -} have been increasingly used to identify the sources and pathways of nitrogen in river systems. The {delta}{sup 15}N value of NO{sub 3}{sup -} is a useful indicator to evaluate the contributions of sewage and/or animal waste to NO{sub 3}{sup -} load, and the {delta}{sup 18}O value can be used for estimation of the contribution of NO{sub 3}{sup -} derived through atmospheric deposition. The microbial denitrification method is currently a most useful tool to measure the {delta}{sup 15}N and {delta}{sup 18}O values of NO{sub 3}{sup -} simultaneously, because of its capability for high throughput of samples. This method allows us to conduct a comprehensive investigation of spatial and temporal variations and mechanisms of nitrogen transport and transformation in rivers and catchments in more precise and effective manner. (author)

  8. The ({sup 18}O, {sup 16}O) reaction as a probe for nuclear spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Cappuzzello, F.; Bondì, M.; Nicolosi, D.; Tropea, S. [INFN - Laboratori Nazionali del Sud, Via S. Sofia 62, I-95125 Catania, Italy and Dipartimento di Fisica e Astronomia, Università di Catania, Via S. Sofia 64, I-95125 Catania (Italy); Agodi, A.; Carbone, D.; Cavallaro, M.; Cunsolo, A. [INFN - Laboratori Nazionali del Sud, Via S. Sofia 62, I-95125 Catania (Italy); Borello-Lewin, T.; Rodrigues, M. R. D. [Instituto de Física - Universidade de São Paulo, Rua do Matão Travessa R Nr.187, 05508-090 Cidade Universitária, São Paulo (Brazil); De Napoli, M. [INFN - Sezione di Catania, Via S. Sofia 64, I-95125 Catania (Italy); Linares, R. [Instituto de Física, Universidade Federal Fluminense, Avenida Litoranea s/n, Gragoata, 24210-340, Niteroi, RJ (Brazil); Foti, A. [Dipartimento di Fisica e Astronomia, Università di Catania, Via S. Sofia 64, I-95125 Catania, Italy and INFN - Sezione di Catania, Via S. Sofia 64, I-95125 Catania (Italy)

    2014-11-11

    The response of nuclei to the ({sup 18}O, {sup 16}O) two-neutron transfer reaction at 84 MeV incident energy has been systematically studied at the Catania INFN-LNS laboratory. The experiments were performed using several solid targets from light ({sup 9}Be, {sup 11}B, {sup 12,13}C, {sup 16}O, {sup 28}Si) to heavy ones ({sup 58,64}Ni, {sup 120}Sn, {sup 208}Pb). The {sup 16}O ejectiles were detected at forward angles by the MAGNEX magnetic spectrometer. Exploiting the large momentum acceptance (−10%, +14%) and solid angle (50 msr) of the spectrometer, energy spectra were obtained with a relevant yield up to about 20 MeV excitation energy. The application of the powerful trajectory reconstruction technique did allow to get energy spectra with energy resolution of about 150 keV and angular distributions with angular resolution better than 0.3°. A common feature observed with light nuclei is the appearance of unknown resonant structures at high excitation energy. The strong population of these latter together with the measured width can reveal the excitation of a collective mode connected with the transfer of a pair.

  9. Oxygen exchange between C18O2 and ''acidic'' oxide and zeolite catalysts

    International Nuclear Information System (INIS)

    Peri, J.B.

    1975-01-01

    The exchange of oxygen between C 18 O 2 and several high-area oxides, including silica, γ-alumina, silica--alumina, and zeolite catalysts, was studied. Infrared spectra of adsorbed CO 2 and of surface ''carbonates'' were used to follow the rate of oxygen exchange and investigate the nature of unusually exchangeable surface oxide ions, present at low concentrations. Interaction of CO 2 with the surface typically produced initial exchange of one oxygen atom, as expected from interaction with a single oxide ion (CO 2 + O 2- reversible CO 3 2- ), and the number of exchangeable ions increased with increasing temperature. The rate of oxygen exchange did not correlate with chemisorption to form stable surface carbonates or with the extent of strong physical adsorption of CO 2 . With dry silica, exchange was insignificant below 600 0 ; with catalytically active zeolites and dry γ-alumina, it was detectable at 200 0 and fairly rapid at 300--400 0 . Silica--alumina required 100--150 0 higher temperature for exchange than did an active zeolite. Activity for cracking and other hydrocarbon reactions may be related to the ease of exchange of some surface oxide ions with CO 2 . Active zeolites have reactive oxide sites resembling those on dry γ-alumina, but such sites on zeolites are probably less-readily eliminated by chemisorption of H 2 O or other compounds. (U.S.)

  10. States of 15C via the (18O,16O) reaction

    CERN Document Server

    Cappuzzello, F; Cunsolo, A; Foti, A; Orrigo, S E A; Rodrigues, M R D; Borello-Lewin, T; Carbone, D; Schillaci, C

    2010-01-01

    A study of the 15C states was pursued in 2008 at the Catania INFN-LNS laboratory by the 13C(18O,16O)15C reaction at 84 MeV incident energy. The 16O ejectiles were detected at forward angles by the MAGNEX magnetic spectrometer. Thanks to an innovative technique the ejectiles were identified without the need of time of flight measurements. Exploiting the large momentum acceptance (25%) and solid angle (50 msr) of the spectrometer, the 15C energy spectra were obtained with a quite relevant yield up to about 20 MeV excitation energy. The application of the powerful technique of the trajectory reconstruction did allow to get an energy resolution of about 250 keV FWHM, limited mainly by straggling effects. The spectra show several known low lying states up to about 7 MeV excitation energy as well as two unknown resonant structures at about 11.4 and 13.5 MeV. The strong excitation of these latter together with the measured width of about 2 MeV FWHM could indicate the presence of collective modes of excitation connec...

  11. Reconstruction of drip-water δ18O based on calcite oxygen and clumped isotopes of speleothems from Bunker Cave (Germany

    Directory of Open Access Journals (Sweden)

    T. Kluge

    2013-02-01

    Full Text Available The geochemical signature of many speleothems used for reconstruction of past continental climates is affected by kinetic isotope fractionation. This limits quantitative paleoclimate reconstruction and, in cases where the kinetic fractionation varies with time, also affects relative paleoclimate interpretations. In carbonate archive research, clumped isotope thermometry is typically used as proxy for absolute temperatures. In the case of speleothems, however, clumped isotopes provide a sensitive indicator for disequilibrium effects. The extent of kinetic fractionation co-varies in Δ47 and δ18O so that it can be used to account for disequilibrium in δ18O and to extract the past drip-water composition. Here we apply this approach to stalagmites from Bunker Cave (Germany and calculate drip-water δ18Ow values for the Eemian, MIS3, and the Holocene, relying on independent temperature estimates and accounting for disequilibrium. Applying the co-variation method to modern calcite precipitates yields drip-water δ18Ow values in agreement with modern cave drip-water δ18Ow of −7.9 ± 0.3‰, despite large and variable disequilibrium effects in both calcite δ18Oc and Δ47. Reconstructed paleo-drip-water δ18Ow values are lower during colder periods (e.g., MIS3: −8.6 ± 0.4‰ and the early Holocene at 11 ka: −9.7 ± 0.2‰ and show higher values during warmer climatic periods (e.g., the Eemian: −7.6 ± 0.2‰ and the Holocene Climatic Optimum: −7.2 ± 0.3‰. This new approach offers a unique possibility for quantitative climate reconstruction including the assessment of past hydrological conditions while accounting for disequilibrium effects.

  12. Monitoring of a fast-growing speleothem site from the Han-sur-Lesse cave, Belgium, indicates equilibrium deposition of the seasonal δ18O and δ13C signals in the calcite

    Science.gov (United States)

    Van Rampelbergh, M.; Verheyden, S.; Allan, M.; Quinif, Y.; Keppens, E.; Claeys, P.

    2014-10-01

    Speleothems provide paleoclimate information on multimillennial to decadal scales in the Holocene. However, seasonal or even monthly resolved records remain scarce. Such records require fast-growing stalagmites and a good understanding of the proxy system on very short timescales. The Proserpine stalagmite from the Han-sur-Less cave (Belgium) displays well-defined/clearly visible darker and lighter seasonal layers of 0.5 to 2 mm thickness per single layer, which allows a measuring resolution at a monthly scale. Through a regular cave monitoring, we acquired a good understanding of how δ18O and δ13C signals in modern calcite reflect climate variations on the seasonal scale. From December to June, outside temperatures are cold, inducing low cave air and water temperature, and bio-productivity in the soil is limited, leading to lower pCO2 and higher δ13C values of the CO2 in the cave air. From June to December, the measured factors display an opposite behavior. The absence of epikarst water recharge between May and October increases prior calcite precipitation (PCP) in the vadose zone, causing drip water to display increasing pH and δ13C values over the summer months. Water recharge of the epikarst in winter diminishes the effect of PCP and as a result the pH and δ13C of the drip water gradually decrease. The δ18O and δ13C signals of fresh calcite precipitated on glass slabs also vary seasonally and are both reflecting equilibrium conditions. Lowest δ18O values occur during the summer, when the δ13C values are high. The δ18O values of the calcite display seasonal variations due to changes in the cave air and water temperature. The δ13C values reflect the seasonal variation of the δ13CDIC of the drip water, which is affected by the intensity of PCP. This same anticorrelation of the δ18O versus the δ13C signals is seen in the monthly resolved speleothem record that covers the period between 1976 and 1985 AD. Dark layers display lower δ18O and higher δ13C

  13. Oxygen isotope variations in phosphate of biogenic apatites. Pt. 2. Phosphorite rocks

    Energy Technology Data Exchange (ETDEWEB)

    Kolodny, Y; Luz, B; Shemesh, A [Hebrew Univ., Jerusalem (Israel). Dept. of Geology

    1983-09-01

    Phosphorites from sedimentary sequences ranging in age from Archaen to Recent were analysed for delta/sup 18/O in both the PO/sub 4/ (delta/sup 18/Osub(p)) and CO/sub 3/ (delta/sup 18/Osub(c)) in the apatite lattice. The oxygen isotope record is considerably better preserved in phosphates than in either carbonates or cherts. The use of the Longinelli and Nuti temperature equation yields temperatures for Recent phosphorites that are in good agreement with those measured in the field. The delta/sup 18/Osub(p) values of ancient phosphorites decrease with increasing age. These changes with time are not likely to be due to post-depositional exchange. Changes in delta/sup 18/O values of seawater and variations of temperatures with time can account for the delta/sup 18/Osub(p) time trend, but the latter explanation is preferred. In Ancient phosphorites delta/sup 18/Osub(c) in structurally bound carbonate in apatite is not a reliable geochemical indicator.

  14. Investigation of changes in {delta}{sup 13}C of PAHs during phytoremediation of coal tar-contaminated soils

    Energy Technology Data Exchange (ETDEWEB)

    Mick Cooper; Cheng-Gong Sun; Margaret Smith; Harry Duncan; Colin Snape [University of Nottingham, Nottingham (United Kingdom). School of Chemical Environmental and Mining Engineering

    2007-07-01

    It has been shown that phytoremediation of polyaromatic hydrocarbon (PAH) contaminated land is a useful, low cost, low maintenance method of cleaning up land at former gas and coking works. However, PAH degradation in the soil and sediment is slow, but PAHs may be degraded through properly stimulated soil micro-organisms. Here we describe a laboratory trial, employing the clover Trifolium pretense (L.)(TP), which was grown in samples of soil contaminated by fresh coal tar, and in soil heavily contaminated by PAHs, obtained from a former coking works. As the latter substrate was 'naturally' contaminated, it contained both pure PAHs and their derivatives, and was thus considered fully 'weathered', and contained recalcitrant PAH species. Conventional analytical techniques (for example, GC-MS) generally provide little information on the source of pollutants such as PAHs. Previous work has established, however, that significant differences existed in the {sup 13}C/{sup 12}C isotopic ratios between PAHs from various sources. Source apportionment of PAH contamination by stable isotope analysis is a powerful technique, but one which assumes that isotopic fractionation is not a significant factor in aged or bioaltered matrices. Phytoremediation trials described here have been utilised in order to determine whether or not any such fractionation of {sup 13}C occurs during the process. Although PAH distributions can be markedly altered by biodegradation, it has been demonstrated that, for low temperature coal tar, the carbon stable isotopic values of the parent PAHs remain fairly constant. 22 refs., 2 figs., 5 tabs.

  15. A dynamic soil chamber system coupled with a tunable diode laser for online measurements of delta-13C, delta-18O, and efflux rate of soil respired CO2

    Energy Technology Data Exchange (ETDEWEB)

    Powers, Heath H [Los Alamos National Laboratory; Mcdowell, Nate [Los Alamos National Laboratory; Hanson, David [UNM; Hunt, John [LANDCARE RESEARCH

    2009-01-01

    High frequency observations of the stable isotopic composition of CO(2) effluxes from soil have been sparse due in part to measurement challenges. We have developed an open-system method that utilizes a flow-through chamber coupled to a tunable diode laser (TDL) to quantify the rate of soil CO(2) efflux and its delta(13)C and delta(18)O values (delta(13)C(R) and delta(18)O(R), respectively). We tested the method first in the laboratory using an artificial soil test column and then in a semi-arid woodland. We found that the CO(2) efflux rates of 1.2 to 7.3 micromol m(-2) s(-1) measured by the chamber-TDL system were similar to measurements made using the chamber and an infrared gas analyzer (IRGA) (R(2) = 0.99) and compared well with efflux rates generated from the soil test column (R(2) = 0.94). Measured delta(13)C and delta(18)O values of CO(2) efflux using the chamber-TDL system at 2 min intervals were not significantly different from source air values across all efflux rates after accounting for diffusive enrichment. Field measurements during drought demonstrated a strong dependency of CO(2) efflux and isotopic composition on soil water content. Addition of water to the soil beneath the chamber resulted in average changes of +6.9 micromol m(-2) s(-1), -5.0 per thousand, and -55.0 per thousand for soil CO(2) efflux, delta(13)C(R) and delta(18)O(R), respectively. All three variables initiated responses within 2 min of water addition, with peak responses observed within 10 min for isotopes and 20 min for efflux. The observed delta(18)O(R) was more enriched than predicted from temperature-dependent H(2)O-CO(2) equilibration theory, similar to other recent observations of delta(18)O(R) from dry soils (Wingate L, Seibt U, Maseyk K, Ogee J, Almeida P, Yakir D, Pereira JS, Mencuccini M. Global Change Biol. 2008; 14: 2178). The soil chamber coupled with the TDL was found to be an effective method for capturing soil CO(2) efflux and its stable isotope composition at high

  16. Calcium manganese oxides as oxygen evolution catalysts: O2 formation pathways indicated by 18O-labelling studies.

    Science.gov (United States)

    Shevela, Dmitriy; Koroidov, Sergey; Najafpour, M Mahdi; Messinger, Johannes; Kurz, Philipp

    2011-05-02

    Oxygen evolution catalysed by calcium manganese and manganese-only oxides was studied in (18)O-enriched water. Using membrane-inlet mass spectrometry, we monitored the formation of the different O(2) isotopologues (16)O(2), (16)O(18)O and (18)O(2) in such reactions simultaneously with good time resolution. From the analysis of the data, we conclude that entirely different pathways of dioxygen formation catalysis exist for reactions involving hydrogen peroxide (H(2)O(2)), hydrogen persulfate (HSO(5)(-)) or single-electron oxidants such as Ce(IV) and [Ru(III) (bipy)(3)](3+) . Like the studied oxide catalysts, the active sites of manganese catalase and the oxygen-evolving complex (OEC) of photosystem II (PSII) consist of μ-oxido manganese or μ-oxido calcium manganese sites. The studied processes show very similar (18)O-labelling behaviour to the natural enzymes and are therefore interesting model systems for in vivo oxygen formation by manganese metalloenzymes such as PSII. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Planktonic primary production in estuaries: a comparison of the 14C, O2 and 18O methods

    NARCIS (Netherlands)

    Gazeau, F.P.H.; Middelburg, J.J.; Loijens, M.; Vanderborght, J.P.; Pizay, M-D.; Gattuso, J.P.

    2007-01-01

    Rates of primary production were measured in 2 estuaries (Randers Fjord, Denmark, and the Scheldt estuary, Belgium/The Netherlands) using 3 different incubation methods: (1) the oxygen light-dark method (O2-LD), (2) 14C incorporation and (3) 18O labeling. Estimates based on the 14C incorporation

  18. In folio study of carbonic anhydrase and Rubisco activities in higher C3 plants using 18O and mass spectrometry

    International Nuclear Information System (INIS)

    Peltier, G.; Despax, V.; Dimon, B.; Rumeau, D.; Tourneux, C.

    1994-01-01

    This document studies the effects of a mild water stress and carbonic anhydrase activity by ethoxyzolamide (EZA) on the diffusion of CO 2 in leaves, by 18 O labelling of O 2 and of CO 2 associated to mass spectrometry. (A.B.). 5 refs., 2 figs

  19. The astrophysical S-factor of the direct 18O(p, γ)19F capture by the ANC method

    Science.gov (United States)

    Burjan, V.; Hons, Z.; Kroha, V.; Mrázek, J.; Piskoř, Š.; Mukhamedzhanov, A. M.; Trache, L.; Tribble, R. E.; La Cognata, M.; Lamia, L.; Pizzone, G. R.; Romano, S.; Spitaleri, C.; Tumino, A.

    2018-01-01

    We attempted to determine the astrophysical S-factor of the direct part of the 18O(p, γ)19F capture by the indirect method of asymptotic normalization coefficients (ANC). We measured the differential cross section of the transfer reaction 18O(3He, d)19F at a 3He energy of 24.6 MeV. The measurement was realized on the cyclotron of the NPI in Řež, Czech Republic, with the gas target consisting of the high purity 18O (99.9 %). The reaction products were measured by eight ΔE-E telescopes composed from thin and thick silicon surface-barrier detectors. The parameters of the optical model for the input channel were deduced by means of the code ECIS and the analysis of transfer reactions to 12 levels of the 19F nucleus up to 8.014 MeV was made by the code FRESCO. The deduced ANCs were then used to specify the direct contribution to the 18O(p, γ)19F capture process and were compared with the mutually different results of two works.

  20. A new mechanism for the two-step d18O signal at the Eocene-Oligocene boundary

    NARCIS (Netherlands)

    Tigchelaar, M.; von der Heydt, A.S.; Dijkstra, H.A.

    2011-01-01

    The most marked step in the global climate transition from “Greenhouse” to “Icehouse” Earth occurred at the Eocene-Oligocene (E-O) boundary, 33.7 Ma. Evidence for climatic changes comes from many sources, including the marine benthic 18O record, showing an increase by 1.2– 1.5‰ at this time. This

  1. Abraham Reef Stable Isotope Data (delta 13C, delta 18O, delta 14C) for 1635-1957

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Site: Abraham Reef, 22ó 06'S, 153ó 00'E, Porites australiensus, Radiocarbon (delta 14C) and Stable Isotope (del 18O and del 13C) results from bi-annual samples from...

  2. "1"3CO/C"1"8O Gradients across the Disks of Nearby Spiral Galaxies

    International Nuclear Information System (INIS)

    Jiménez-Donaire, María J.; Cormier, Diane; Bigiel, Frank; Leroy, Adam K.; Gallagher, Molly; Krumholz, Mark R.; Usero, Antonio; Hughes, Annie; Kramer, Carsten; Meier, David; Murphy, Eric; Pety, Jérôme; Schuster, Karl; Schinnerer, Eva; Sliwa, Kazimierz; Tomicic, Neven; Schruba, Andreas

    2017-01-01

    We use the IRAM Large Program EMPIRE and new high-resolution ALMA data to measure "1"3CO(1-0)/C"1"8O(1-0) intensity ratios across nine nearby spiral galaxies. These isotopologues of "1"2CO are typically optically thin across most of the area in galaxy disks, and this ratio allows us to gauge their relative abundance due to chemistry or stellar nucleosynthesis effects. Resolved "1"3CO/C"1"8O gradients across normal galaxies have been rare due to the faintness of these lines. We find a mean "1"3CO/C"1"8O ratio of 6.0 ± 0.9 for the central regions of our galaxies. This agrees well with results in the Milky Way, but differs from results for starburst galaxies (3.4 ± 0.9) and ultraluminous infrared galaxies (1.1 ± 0.4). In our sample, the "1"3CO/C"1"8O ratio consistently increases with increasing galactocentric radius and decreases with increasing star formation rate surface density. These trends could be explained if the isotopic abundances are altered by fractionation; the sense of the trends also agrees with those expected for carbon and oxygen isotopic abundance variations due to selective enrichment by massive stars.

  3. Measurements of the 18O/16O ratio of dissolved oxygen in the North Sea during FLEX 76

    International Nuclear Information System (INIS)

    Foerstel, H.; Zielke, H.

    1978-01-01

    In spring 1976 a special part of the North Sea was the subject of research by a group of international scientists in the so-called 'Fladenground Experiment 1976 (FLEX 76). The team participated aboard the research ship Planet in an attempt to study the oxygen exchange between sea and atmosphere and the mixing within the water column. The water samples were taken in a small area during a period of two weeks. The water depth did not exceed 140 m. The dissolved oxygen was extracted using a vacuum system, and stored after adsorption on a molecular sieve. In the laboratory the oxygen was burned to carbon dioxide and the 18 O/ 16 O ratio was determined with a mass spectrometer. At the surface the sea water was saturated with air and showed the 18 O/ 16 O ratio of atmospheric oxygen. Towards the deeper layers the oxygen was consumed, and as a result the heavier isotope 18 O was enriched. This enrichment can be seen in a very marked manner even in the upper 100 m of the sea. In our case the 18 O enrichment indicates that the mixing processes did not exchange the oxygen of the layers beneath the surface rapidly. (Auth.)

  4. Application of 18O and 2H natural isotopes for groundwater study in Semarang Basin, Central Java

    International Nuclear Information System (INIS)

    Rasi Prasetio; Satrio

    2015-01-01

    As a big city that support industrialism, Semarang has increasing needs of fresh water supply which is mostly provided by ground water. The utilization of groundwater must consider sustainability and environmental preservation aspects, as water is basic needs for human being. Therefore, the knowledge about groundwater dynamics is important to manage groundwater utilization. Isotope hydrology technique using 18 O and 2 H isotopes has been applied to investigate groundwater dynamics and can be taken as consideration for groundwater management. For this purpose, water samples have been collected from various water sources such as springs, deep monitoring wells, dug wells, streams and rain water for 18 O and 2 H isotopes analysis. The results show that isotopes composition of groundwater varied between -8.77‰ to -4.76‰ for δ 18 O and -56.6‰ to -29.4‰ for δ 2 H. Isotopes composition for unconfined groundwater in most of study area are relatively uniform, i.e. between -5.9‰ to -6.6‰ for δ 18 O and -35.1‰ to -40.4‰ for δ 2 H, except in some minor places that have more depleted and more enriched composition. This distribution indicates that the unconfined aquifer is depend on local recharge. While most of isotopes composition of deep confined aquifer plotted around isotopes composition of Ungaran's rain water, indicates that the recharge area of these confined groundwater were originated from this elevation or higher. (author)

  5. How yield relates to ash content, Delta 13C and Delta 18O in maize grown under different water regimes.

    Science.gov (United States)

    Cabrera-Bosquet, Llorenç; Sánchez, Ciro; Araus, José Luis

    2009-11-01

    Stable isotopes have proved a valuable phenotyping tool when breeding for yield potential and drought adaptation; however, the cost and technical skills involved in isotope analysis limit its large-scale application in breeding programmes. This is particularly so for Delta(18)O despite the potential relevance of this trait in C(4) crops. The accumulation of minerals (measured as ash content) has been proposed as an inexpensive way to evaluate drought adaptation and yield in C(3) cereals, but little is known of the usefulness of this measure in C(4) cereals such as maize (Zea mays). The present study investigates how yield relates to ash content, Delta(13)C and Delta(18)O, and evaluates the use of ash content as an alternative or complementary criterion to stable isotopes in assessing yield potential and drought resistance in maize. A set of tropical maize hybrids developed by CIMMYT were subjected to different water availabilities, in order to induce water stress during the reproductive stages under field conditions. Ash content and Delta(13)C were determined in leaves and kernels. In addition, Delta(18)O was measured in kernels. Water regime significantly affected yield, ash content and stable isotopes. The results revealed a close relationship between ash content in leaves and the traits informing about plant water status. Ash content in kernels appeared to reflect differences in sink-source balance. Genotypic variation in grain yield was mainly explained by the combination of ash content and Delta(18)O, whilst Delta(13)C did not explain a significant percentage of such variation. Ash content in leaves and kernels proved a useful alternative or complementary criterion to Delta(18)O in kernels for assessing yield performance in maize grown under drought conditions.

  6. An Experimental Study on What Controls the Ratios of 18O/16O and 17O/16O of O2 During Microbial Respiration

    Science.gov (United States)

    Stolper, D. A.; Ward, B. B.; Fischer, W. W.; Bender, M. L.

    2015-12-01

    18O/16O and 17O/16O ratios of atmospheric and dissolved oceanic O2 are key biogeochemical tracers of total photosynthesis and respiration on global to local length scales and glacial/interglacial time scales (Luz et al., 1999). Critical to the use of these ratios as biogeochemical tracers is knowledge of how they are affected by production, consumption, and transport of O2. We present new measurements of O2 respiration by E. coli and N. oceanus, an ammonia oxidizing bacterium, to test three assumptions of isotopically enabled models of the O2 cycle: (i) laboratory-measured respiratory 18O/16O isotope effects (18α) of microorganisms are constant under all experimental and natural conditions (e.g., temperature and growth rate); (ii) the respiratory 'mass law' relationship between 18O/16O and 17O/16O [17α = (18α)β] is universal; and (iii) 18α and β for aerobic ammonia and organic carbon oxidation are identical. For E. coli, we find that both 18α and β are variable. From 37°C to 15°C, 18α varies linearly with temperature from 17 to 14‰, and β varies linearly from 0.513 to 0.508. 18α and β do not appear to vary with growth rate (as tested using different carbon sources). Both 18α and β are lower than previous observations for bacteria: 18α = 17-20‰ (Kiddon et al., 1993) and β = 0.515 (Luz and Barkan, 2005). We were able to simulate the observed temperature dependence of 18α and β using a model of respiration with two isotopically discriminating steps: O2 binding to cytochrome bo oxidase (the respiratory enzyme) and reduction of O2 to H2O. Finally, initial results on N. oceanus suggest it has similar values for 18α and β as previously studied aerobic bacteria that consume organic carbon, providing the first support for assumption (iii). Based on these results, isotopically constrained biogeochemical models of O2 cycling may need to consider a temperature dependence for 18α and β for microbial respiration. For example, these results may

  7. Probability distribution functions of δ15N and δ18O in groundwater nitrate to probabilistically solve complex mixing scenarios

    Science.gov (United States)

    Chrystal, A.; Heikoop, J. M.; Davis, P.; Syme, J.; Hagerty, S.; Perkins, G.; Larson, T. E.; Longmire, P.; Fessenden, J. E.

    2010-12-01

    Elevated nitrate (NO3-) concentrations in drinking water pose a health risk to the public. The dual stable isotopic signatures of δ15N and δ18O in NO3- in surface- and groundwater are often used to identify and distinguish among sources of NO3- (e.g., sewage, fertilizer, atmospheric deposition). In oxic groundwaters where no denitrification is occurring, direct calculations of mixing fractions using a mass balance approach can be performed if three or fewer sources of NO3- are present, and if the stable isotope ratios of the source terms are defined. There are several limitations to this approach. First, direct calculations of mixing fractions are not possible when four or more NO3- sources may be present. Simple mixing calculations also rely upon treating source isotopic compositions as a single value; however these sources themselves exhibit ranges in stable isotope ratios. More information can be gained by using a probabilistic approach to account for the range and distribution of stable isotope ratios in each source. Fitting probability density functions (PDFs) to the isotopic compositions for each source term reveals that some values within a given isotopic range are more likely to occur than others. We compiled a data set of dual isotopes in NO3- sources by combining our measurements with data collected through extensive literature review. We fit each source term with a PDF, and show a new method to probabilistically solve multiple component mixing scenarios with source isotopic composition uncertainty. This method is based on a modified use of a tri-linear diagram. First, source term PDFs are sampled numerous times using a variation of stratified random sampling, Latin Hypercube Sampling. For each set of sampled source isotopic compositions, a reference point is generated close to the measured groundwater sample isotopic composition. This point is used as a vertex to form all possible triangles between all pairs of sampled source isotopic compositions

  8. The 1996 thaw as a {sup 18}O tracer experiment at the lysimeter plant in Wagna; Die Schneeschmelze 1996 als {sup 18}O-Tracerversuch an der Lysimeteranlage in Wagna

    Energy Technology Data Exchange (ETDEWEB)

    Fank, J.; Zojer, H. [Forschungsgesellschaft Joanneum, Graz (Austria). Inst. fuer Geothermie und Hydrogeologie; Stichler, W. [GSF - Forschungszentrum fuer Umwelt und Gesundheit GmbH, Neuherberg (Germany). Inst. fuer Hydrologie

    1999-02-01

    In the year 1991 a research site was set up in Wagna in the western Leibnitz Field (Styria) which permits an examination of seepage water movement and of material transport as a function of the permeability of the uppermost soil layers and the underlying more coarsly clastic sediments under locale-specific natural management systems. Research at this site is largely based on hydrochemical and isotope-hydrological analysis. The {sup 18}O isotope is an ideal natural tracer of water movement. Infiltration water from the thaw following a snowy winter was displaced downward into the unsaturated zone as a result of a major precipitation event of 85.5 mm from April 2 to 5, 1996. This displacement is evident in the {sup 18}O concentrations of the seepage water at various measuring depths. The displacement is associated with recharge events, thaw processes tending to produce dispersive flows and precipitation events leading to ``piston flow effects. Winter precipitation water reaches a depth of 60 to 70 cm by mid-April. The attenuated {sup 18}O concentration reveals the predominant flow characteristics in the different compartments of the unsaturated zone (finely clastic soils, gravels, and sands). [Deutsch] Im Jahre 1991 wurde in Wagna, im westlichen Leibnitzer Feld (Steiermark), eine Forschungsstation errichtet, die es erlaubt, unter ortsueblichen, natuerlichen Bewirtschaftungssystemen die Sickerwasserbewegung und den Transport von Stoffen in Abhaengigkeit von der Durchlaessigkeit der obersten Bodenschichten und der darunter folgenden groeberklastischen Sedimente vor allem auf Grundlage der hydrochemischen und isotopenhydrologischen Analytik zu untesuchen. Die Verwendung des {sup 18}O-Isotops als natuerlicher Tracer repraesentiert in idealer Weise die Bewegung des Wassers. Infiltrationswasser aus der Schneeschmelze nach einem schneereichen Winter wurde durch ein starkes Niederschlagsereignis von 85.6 mm zwischen 2. und 5. April 1996 in der ungesaettigten Zone

  9. Meaning of the Deuterium excess in the interpretation of δ 18O and δ 2H stable isotopes in hydrogeological studies

    International Nuclear Information System (INIS)

    Valencia, Jacinto

    2013-01-01

    An analysis element that helps with information on the interpretation of stable isotopes δ 18 O and deuterium in hydrogeological studies is called deuterium excess δ. In the present study, it has been used to interpret the weather, evaporation, humidity and wind conditions at the time of the precipitation in the Altiplano region of Puno, which have led to leaks of mine under study. The values obtained from the calculation of the deuterium excess δ of the seepage water samples are in the order of +15o/oo, indicating that the characteristics of the rainfall in the region have dominated high land desert climate conditions, different the current, ie, low humidity at the time of precipitation and further filtering these waters have received contribution of close water basin, evaporated and could come from Lake Titicaca. (author).

  10. Climatic changes during the early Medieval and recent periods inferred from δ13C and δ18O of Siberian larch trees

    Science.gov (United States)

    Sidorova, O. V.; Matthias Saurer, Rolf Siegwolf

    2010-12-01

    We report unique isotope datasets for δ13C and δ18O of wood and cellulose of larch trees (Larix cajanderi Mayr.) from Northeastern Yakutia [70°N-148°E] for the early Medieval (AD 900-1000) and recent (AD 1880-2004) periods. During the recent period June, July, and August air temperatures were positively correlated with δ13C and δ18O of wood and cellulose, while July precipitation was negatively correlated. The positive correlation with one of the warmest months (July) in Northeastern Yakutia could indicate high photosynthetic capacity, because warm and dry conditions cause stomatal closure and lower the isotopic fractionation, leading to less negative δ13C values. Because during July, the soil water is still frozen at a soil depth of 20-30 cm, the water accessibility for trees is limited, which can lead to drought situations. An increase in water availability allows for a higher stomatal conductance, resulting in lower δ13C values, leading to a negative relationship with summer precipitation. Furthermore, the vapor pressure deficit of July and August was significantly correlated with δ13C of wood and cellulose, indicating decreased stomatal conductance, an expression of moderate drought. This leads to reduced 13CO2 discrimination and less negative δ13C values. The simultaneous increase of δ18O also indicates a reduction in stomatal conductance under rather dry conditions or drought. Comparative analyses between mean isotope values for the AD 900-1000 and AD 1880-2004 periods indicate similar ranges of climatic conditions, with the exception of the period AD 1950-2004, which is characterized by increased summer drought. Whilst isotopic ratios in cellulose are reliably related to climatic variables, those in whole wood showed even stronger relationships during some periods. Strong positive correlations between δ18O of cellulose and Greenland ice-core data were detected for the beginning of the Medieval period (r=0.86; pdata, and gain a wider insight into

  11. W18O49 nanorods decorated with Ag/AgCl nanoparticles as highly-sensitive gas-sensing material and visible-light-driven photocatalyst

    International Nuclear Information System (INIS)

    Sun Shibin; Chang Xueting; Dong Lihua; Zhang Yidong; Li Zhenjiang; Qiu Yanyan

    2011-01-01

    A novel gas-sensing material and photocatalyst was successfully obtained by decorating Ag/AgCl nanoparticles on the W 18 O 49 nanorods through a clean photochemical route. The as-prepared samples were characterized using combined techniques of X-ray diffractometry, electron microscopy, energy dispersive X-ray spectrometry, and X-ray photoelectron spectroscopy. Gas-sensing measurements indicate that the Ag/AgCl/W 18 O 49 NRs sensors exhibit superior reducing gas-sensing properties to those of bare W 18 O 49 NRs, and they are highly selective and sensitive to NH 3 , acetone, and H 2 S with short response and recovery times. The Ag/AgCl/W 18 O 49 NRs photocatlysts also possess higher photocatalytic performance than bare W 18 O 49 NRs for degradation of methyl orange under simulated sunlight irradiation. Possible mechanisms concerning the enhancement of gas-sensing and photocatalytic activities of the Ag/AgCl/W 18 O 49 NRs composite were proposed. - Graphical Abstract: The Ag/AgCl nanoparticles adhered well to the W 18 O 49 nanorod. The Ag could act as transfer center of the photoexcited carriers, prohibiting their recombinations in both W 18 O 49 and AgCl. Highlights: → Ag/AgCl/W 18 O 49 NRs were successfully obtained via a clean photochemical route. → The Ag/AgCl nanoparticles decorated on the W 18 O 49 NRs possessed cladding structure. → The Ag/AgCl/W 18 O 49 NRs exhibited excellent gas-sensing and photocatalytic properties.

  12. Size-dependent δ18O and δ13C variations in a planktic foraminiferal Neogloboquadrina pachyderma (sinistral) record from Chukchi Plateau: implications for (sub)surface water conditions in the western Arctic Ocean over the past 50 ka

    Science.gov (United States)

    Wang, R.; Xiao, W.; Mei, J.; Polyak, L.

    2017-12-01

    Oxygen and carbon stable isotopes in planktic foraminifera Neogloboquadrina pachyderma (sinistral) (Nps) have a promising potential for reconstructing (sub)surface water conditions in the Arctic Ocean. Size-dependent (63-154 µm, 154-250 µm, and >250 µm) Nps δ18O and δ13C were measured along with Ice Rafted Debris (IRD) and scanned XRF Ca and Mn contents in sediment core ARC3-P31 from the Chukchi Plateau (434 m water depth) representing paleoceanographic conditions during the last 50 ka (Marine Isotope Stages 1-3). While the interval corresponding to the Last Glacial Maximum is represented by a hiatus, the following deglaciation is clearly marked by a strong depletion in both δ18O and δ13C in all Nps size fractions along with a peak in detrital carbonate IRD indicative of the Canadian Arctic Archipelago provenance. This pronounced feature presumably indicates a collapse event of the northwestern Laurentide Ice Sheet, potentially linked to the rising sea level. In the overall record under study, average values of Nps δ18O and δ13C fluctuate in the range of 1.2-2.1‰ and 0.3-0.9 ‰, respectively. Mid-size Nps δ18O values (154-250 µm) are in average lighter by 0.2-0.5 ‰ than those of small (63-154 µm) and large (>250 µm) Nps tests. This offset may indicate a different water-depth dwelling, possibly affected by a relatively warm subsurface Atlantic water.

  13. Determination of the δ2H and δ18O of soil water and water in plant matter; RSIL lab code 1700

    Science.gov (United States)

    Revesz, Kinga M.; Buck, Bryan; Coplen, Tyler B.

    2012-01-01

    The purpose of the Reston Stable Isotope Laboratory lab code 1700 is to determine the δ2H/1H), abbreviated as δ2H, and the δ18O/16O), abbreviated as δ18O, of soil water and water in plant matter. This method is based on the observation that water and toluene form an azeotropic mixture at 84.1 °C. This temperature is substantially lower than the boiling points of water (100 °C) and toluene (110 °C), but water and toluene are immiscible at ambient temperature. The water content of a soil or plant is determined by weighing, drying, and reweighing a small amount of sample. Sufficient sample to collect 3 to 5 milliliters of water after distillation is loaded into a distillation flask. Sufficient toluene is added so that the sample is immersed throughout the entire distillation to minimize evaporation of water, which would affect the δ2H and δ18O values. The mixture of sample and toluene is heated in a flask to its boiling point (84.1 °C) so that water from the sample and toluene can distill together into a specially designed collection funnel. The temperature of 84.1 °C is maintained until the water has been quantitatively transferred to the collection funnel, at which time the temperature is raised to the boiling point of the remaining component (toluene, 110 °C). The collection funnel is maintained at ambient temperature so that the sample water and toluene can be separated physically. After separation, the sample water is purified by addition of paraffin wax to the container with the sample water, capping the container, and heating to approximately 60 °C to melt the wax. Trace amounts of toluene will dissolve in the wax, purifying the sample water for isotopic analysis. The isotopic composition of the purified water is then determined by equilibration with gaseous hydrogen or carbon dioxide, followed by dual-inlet isotope-ratio mass spectrometry. Because laser-absorption spectrometry is sensitive to organic compounds, such as trace toluene remaining in

  14. Rates and cycles of microbial sulfate reduction in the hyper-saline Dead Sea over the last 200 kyrs from sedimentary d34S and d18O(SO4)

    Science.gov (United States)

    Torfstein, Adi; Turchyn, Alexandra V.

    2017-08-01

    We report the d34S and d18O(SO4) values measured in gypsum, pyrite, and elemental sulfur through a 456-m thick sediment core from the center of the Dead Sea, representing the last 200 kyrs, as well as from the exposed glacial outcrops of the Masada M1 section located on the margins of the modern Dead Sea. The results are used to explore and quantify the evolution of sulfur microbial metabolism in the Dead Sea and to reconstruct the lake’s water column configuration during the late Quaternary. Layers and laminae of primary gypsum, the main sulfur-bearing mineral in the sedimentary column, display the highest d34S and d18O(SO4) in the range of 13-28‰ and 13-30‰, respectively. Within this group, gypsum layers deposited during interglacials have lower d34S and d18O(SO4) relative to those associated with glacial or deglacial stages. The reduced sulfur phases, including chromium reducible sulfur, and secondary gypsum crystals are characterized by extremely low d34S in the range of -27 to +7‰. The d18O(SO4) of the secondary gypsum in the M1 outcrop ranges from 8 to 14‰. The relationship between d34S and d18O(SO4) of primary gypsum suggests that the rate of microbial sulfate reduction was lower during glacial relative to interglacial times. This suggests that the freshening of the lake during glacial wet intervals, and the subsequent rise in sulfate concentrations, slowed the rate of microbial metabolism. Alternatively, this could imply that sulfate-driven anaerobic methane oxidation, the dominant sulfur microbial metabolism today, is a feature of the hypersalinity in the modern Dead Sea. Sedimentary sulfides are quantitatively oxidized during epigenetic exposure, retaining the lower d34S signature; the d18O(SO4) of this secondary gypsum is controlled by oxygen atoms derived equally from atmospheric oxygen and from water, which is likely a unique feature in this hyperarid environment.

  15. Orbital-scale Central Arctic Ocean Temperature Records from Benthic Foraminiferal δ18O and Ostracode Mg/Ca Ratios

    Science.gov (United States)

    Keller, K.; Cronin, T. M.; Dwyer, G. S.; Farmer, J. R.; Poirier, R. K.; Schaller, M. F.

    2017-12-01

    Orbital-scale climate variability is often amplified in the polar region, for example in changes in seawater temperature, sea-ice cover, deep-water formation, ecosystems, heat storage and carbon cycling. Yet, the relationship between the Arctic Ocean and global climate remains poorly understood due largely to limited orbital-scale paleoclimate records, the complicated nature of sea-ice response to climate and limited abundance of deep sea biological proxies. Here we reconstruct central Arctic Ocean bottom temperatures over the last 600 kyr using ostracode Mg/Ca ratios (genus Krithe) and benthic foraminiferal oxygen isotope ratios (δ18Obf - I. teretis, O. tener, P. bulloides, C. reniforme, C. wuellerstorfi) in six sediment cores recovered from the Mendeleev and Northwind Ridges (700- 2726 m water depth). We examined glacial-interglacial cycles in Arctic seawater temperatures and Arctic δ18Obf chronostratigraphy to reconcile effects of changing bottom water temperature, ice volume and regional hydrography on δ18Obf records. Results show lower ( 10-12 mmol/mol) interglacial and higher ( 16-23 mmol/mol) glacial Mg/Ca ratios, signifying intermediate depth ocean warming during glacials of up to 2 ºC. These temperature maxima are likely related to a deepening of the halocline and the corresponding deeper influence of warm Atlantic water. Glacial-interglacial δ18Obf ranges are smaller in the Arctic ( 0.8-1‰ VPDB) than in the global ocean ( 1.8 ‰). However, when the distinct glacial-interglacial temperature histories of the Arctic (glacial warming) and global ocean (glacial cooling) are accounted for, both Arctic and global ocean seawater δ18O values (δ18Osw) exhibit similar 1.2-1.3 ‰ glacial-interglacial ranges. Thus, Arctic δ18Obf confirms glacial Arctic warming inferred from ostracode Mg/Ca. This study will discuss the strengths and limitations of applying paired Mg/Ca and oxygen isotope proxies in reconstructing more robust paleoceanographic changes in the

  16. Pooled versus separate measurements of tree-ring stable isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Dorado Linan, Isabel, E-mail: isabel@gfz-potsdam.de [Universitat de Barcelona, Departament d' Ecologia, Diagonal 645, 08028, Barcelona (Spain); German Centre for Geosciences, Climate Dynamics and Landscape Evolution, Dendro Laboratory, Telegrafenberg, 14473, Potsdam (Germany); Gutierrez, Emilia, E-mail: emgutierrez@ub.edu [Universitat de Barcelona, Departament d' Ecologia, Diagonal 645, 08028, Barcelona (Spain); Helle, Gerhard, E-mail: ghelle@gfz-potsdam.de [German Centre for Geosciences, Climate Dynamics and Landscape Evolution, Dendro Laboratory, Telegrafenberg, 14473, Potsdam (Germany); Heinrich, Ingo, E-mail: heinrich@gfz-potsdam.de [German Centre for Geosciences, Climate Dynamics and Landscape Evolution, Dendro Laboratory, Telegrafenberg, 14473, Potsdam (Germany); Andreu-Hayles, Laia, E-mail: laiandreu@ub.edu [Universitat de Barcelona, Departament d' Ecologia, Diagonal 645, 08028, Barcelona (Spain); Tree-Ring Laboratory, Lamont-Doherty Earth Observatory of Columbia University, Palisades NY (United States); Planells, Octavi, E-mail: leocarpus@hotmail.com [Universitat de Barcelona, Departament d' Ecologia, Diagonal 645, 08028, Barcelona (Spain); Leuenberger, Markus, E-mail: leuenberger@climate.unibe.ch [Climate and Environmental Physics, Physics Institute, University of Bern, Sidlerstrasse 5, 3012 Bern (Switzerland); Oeschger Centre of Climate Change Research, University of Bern, Zaehringerstrasse 25, 3012 Bern (Switzerland); Buerger, Carmen, E-mail: buerger@gfz-potsdam.de [German Centre for Geosciences, Climate Dynamics and Landscape Evolution, Dendro Laboratory, Telegrafenberg, 14473, Potsdam (Germany); Schleser, Gerhard, E-mail: schleser@gfz-potsdam.de [German Centre for Geosciences, Climate Dynamics and Landscape Evolution, Dendro Laboratory, Telegrafenberg, 14473, Potsdam (Germany)

    2011-05-01

    {delta}{sup 13}C and {delta}{sup 18}O of tree rings contain time integrated information about the environmental conditions weighted by seasonal growth dynamics and are well established as sources of palaeoclimatic and ecophysiological data. Annually resolved isotope chronologies are frequently produced by pooling dated growth rings from several trees prior to the isotopic analyses. This procedure has the advantage of saving time and resources, but precludes from defining the isotopic error or statistical uncertainty related to the inter-tree variability. Up to now only a few studies have compared isotope series from pooled tree rings with isotopic measurements from individual trees. We tested whether or not the {delta}{sup 13}C and the {delta}{sup 18}O chronologies derived from pooled and from individual tree rings display significant differences at two locations from the Iberian Peninsula to assess advantages and constraints of both methodologies. The comparisons along the period 1900-2003 reveal a good agreement between pooled chronologies and the two mean master series which were created by averaging raw individual values (Mean) or by generating a mass calibrated mean (MassC). In most of the cases, pooled chronologies show high synchronicity with averaged individual samples at interannual scale but some differences also show up especially when comparing {delta}{sup 18}O decadal to multi-decadal variations. Moreover, differences in the first order autocorrelation among individuals may be obscured by pooling strategies. The lack of replication of pooled chronologies prevents detection of a bias due to a higher mass contribution of one sample but uncertainties associated with the analytical process itself, as sample inhomogeneity, seems to account for the observed differences. - Research Highlights: {yields} Pooled {delta}{sup 13}C and {delta}{sup 18}O chronologies are expected to be similar to the mean. {yields} Empirical pooled chronologies {delta}{sup 13}C and

  17. A Two-year Record of Daily Rainfall Isotopes from Fiji: Implications for Reconstructing Precipitation from Speleothem δ18O

    Science.gov (United States)

    Brett, M.; Mattey, D.; Stephens, M.

    2015-12-01

    Oxygen isotopes in speleothem provide opportunities to construct precisely dated records of palaeoclimate variability, underpinned by an understanding of both the regional climate and local controls on isotopes in rainfall and groundwater. For tropical islands, a potential means to reconstruct past rainfall variability is to exploit the generally high correlation between rainfall amount and δ18O: the 'amount effect'. The GNIP program provides δ18O data at monthly resolution for several tropical Pacific islands but there are few data for precipitation isotopes at daily resolution, for investigating the amount effect over different timescales in a tropical maritime setting. Timescales are important since meteoric water feeding a speleothem has undergone storage and mixing in the aquifer system and understanding how the isotope amount effect is preserved in aquifer recharge has fundamental implications on the interpretation of speleothem δ18O in terms of palaeo-precipitation. The islands of Fiji host speleothem caves. Seasonal precipitation is related to the movement of the South Pacific Convergence Zone, and interannual variations in rainfall are coupled to ENSO behaviour. Individual rainfall events are stratiform or convective, with proximal moisture sources. We have daily resolution isotope data for rainfall collected at the University of the South Pacific in Suva, covering every rain event in 2012 and 2013. δ18O varies between -18‰ and +3‰ with the annual weighted averages at -7.6‰ and -6.8‰ respectively, while total recorded rainfall amount is similar in both years. We shall present analysis of our data compared with GNIP, meteorological data and back trajectory analyses to demonstrate the nature of the relationship between rainfall amount and isotopic signatures over this short timescale. Comparison with GNIP data for 2012-13 will shed light on the origin of the amount effect at monthly and seasonal timescales in convective, maritime, tropical

  18. Consistent analysis of peripheral reaction channels and fusion for the 16,18O+58Ni systems

    International Nuclear Information System (INIS)

    Alves, J.J.S.; Gomes, P.R.S.; Lubian, J.; Chamon, L.C.; Pereira, D.; Anjos, R.M.; Rossi, E.S.; Silva, C.P.; Alvarez, M.A.G.; Nobre, G.P.A.; Gasques, L.R.

    2005-01-01

    We have measured elastic scattering and peripheral reaction channel cross sections for the 16,18 O+ 58 Ni systems at ELab=46 MeV. The data were analyzed through extensive coupled-channel calculations. It was investigated the consistency of the present analysis with a previous one at sub-barrier energies. Experimental fusion cross sections for these systems are also compared with the corresponding predictions of the coupled-channel calculations

  19. Multipolarity analysis for 14C high-energy resonance populated by (18O,16O) two-neutron transfer reaction

    International Nuclear Information System (INIS)

    Carbone, D.; Cavallaro, M.; Bondì, M.; Agodi, C.; Cunsolo, A.; Cappuzzello, F.; Azaiez, F.; Franchoo, S.; Khan, E.; Bonaccorso, A.; Fortunato, L.; Foti, A.; Linares, R.; Lubian, J.; Scarpaci, J. A.; Vitturi, A.

    2015-01-01

    The 12 C( 18 O, 16 O) 14 C reaction at 84 MeV incident energy has been explored up to high excitation energy of the residual nucleus thanks to the use of the MAGNEX spectrometer to detect the ejectiles. In the region above the two-neutron separation energy, a resonance has been observed at 16.9 MeV. A multipolarity analysis of the cross section angular distribution indicates an L = 0 character for such a transition

  20. Oxygen isotopic ratios of quartz from wind-erosive soils of southwestern United States in relation to aerosol dust

    Energy Technology Data Exchange (ETDEWEB)

    Sridhar, K.; Jackson, M.L.; Clayton, R.N.; Gillette, D.A.; Hawley, J.W.

    1978-01-01

    The oxygen isotopic ratios (expressed as parts per thousand relative to mean ocean water, SMOW, delta/sup 18/O) of the quartz from 13 soils undergoing much wind erosion during the study period of 1972-1975 in four southwestern states and from comparison areas were determined. The delta/sup 18/O for quartz from eight Texas (TX) and Arizona (AZ) soils range from 13.0 to 15.9 /sup 0///sub 00/. The quartz of the sands and silts coarser than 20 ..mu..m from three of the soils had delta/sup 18/O values ranging from 13.1 to 15.1 /sup 0///sub 00/, characteristic of an ultimate igneous-metamorphic origin. The delta/sup 18/O values increase greatly with decreasing particle size of quartz from three soils ranging from loamy fine sand to loam to clay in texture. The delta/sup 18/O of the 1-10 ..mu..m quartz fraction (aerosol size) ranged from 19.2 to 20.2 /sup 0///sub 00/ (19.55 +- 0.28 /sup 0///sub 00/; +- sigma) for the thirteen soils most affected by dust storms. The oxygen isotopic ratios of 1-10 ..mu..m quartz from three Hawaiian soils and two sediments from Lake Waiau occurring at 3,970 m altitude on the Mauna Kea summit on the Island of Hawaii give a delta/sup 18/O mean of 18.3 +- 0.2 /sup 0///sub 00/.

  1. Calibration of the cross section of the 18O(p, [alpha])15N nuclear reaction at Ep = 1700-1775 keV

    NARCIS (Netherlands)

    Alkemade, P.F.A.; Stap, C.A.M.; Habraken, F.H.P.M.; Weg, W.F. van der

    1988-01-01

    The differential cross section of the 18O(p, α)15N nuclear reaction has been calibrated at proton energies between 1700 and 1775 keV and at a detection angle of 155°. For the calibration, two silicon reference samples and a nickel sample were partially oxidized in enriched 18O. The absolute

  2. Comparative study of the elastic scattering of 178.4 MeV antiprotons by the 16O and 18O isotopes

    International Nuclear Information System (INIS)

    Bruge, G.; Chaumeaux, A.; Birien, P.; Drake, D.M.; Garreta, D.; Janouin, S.; Legrand, D.; Lemaire, M.C.; Mayer, B.; Pain, J.; Peng, J.C.

    1986-01-01

    Elastic scattering of 178.4 MeV anti p has been measured on 16 O and 18 O isotopes. Both macroscopic and microscopic analyses of the data show differences which can be related to the neutron excess in 18 O. (orig.)

  3. Reconstructing relative humidity from plant δ18O and δD as deuterium deviations from the global meteoric water line.

    Science.gov (United States)

    Cellulose δ18O and δD in preserved plant material can provide insights on climates and hydrological cycling in the distant past. However, most studies of plant cellulose have used only one isotope, most commonly δ18O, resulting in difficulties partitioning variation between chang...

  4. Experimental observation of transient δ18O interaction between snow and advective airflow under various temperature gradient conditions

    Directory of Open Access Journals (Sweden)

    P. P. Ebner

    2017-07-01

    Full Text Available Stable water isotopes (δ18O obtained from snow and ice samples of polar regions are used to reconstruct past climate variability, but heat and mass transport processes can affect the isotopic composition. Here we present an experimental study on the effect of airflow on the snow isotopic composition through a snow pack in controlled laboratory conditions. The influence of isothermal and controlled temperature gradient conditions on the δ18O content in the snow and interstitial water vapour is elucidated. The observed disequilibrium between snow and vapour isotopes led to the exchange of isotopes between snow and vapour under non-equilibrium processes, significantly changing the δ18O content of the snow. The type of metamorphism of the snow had a significant influence on this process. These findings are pertinent to the interpretation of the records of stable isotopes of water from ice cores. These laboratory measurements suggest that a highly resolved climate history is relevant for the interpretation of the snow isotopic composition in the field.

  5. Identification of Bottled Zam Zam Water in Malaysian Market using Hydrogen and Oxygen Stable Isotobe Ratios (δ2H and δ18O)

    International Nuclear Information System (INIS)

    Roslanzairi Mostapa; Abdul Kadir Ishak; Kamaruzaman Mohamad; Rohaimah Demanah

    2014-01-01

    The water drawn from the well of Zam Zam is believed by the adherents of Islam to be blessed and capable of treating a variety of ailments. The water originates from a well in an alluvium area, located in Mecca, Saudi Arabia and has been in use since 4000 years ago. Due to the religious significance of the water drawn from this well, bottled versions are very popular among Malaysians. Unfortunately, this disproportionate popularity may entice some unscrupulous dealers to engage in fraudulent behaviour, such as selling ordinary water purported to be Zam Zam water. This unethical practice might very well pose a physical and economical hazard to consumers. Therefore, for the purpose of this preliminary study, five samples of Zam Zam bottled water from different brands were purchased and analyzed using Isotope Ratio Mass Spectrometer (IRMS). For comparison purpose, four samples of zam zam water from Mecca, and two more types of water samples originating from Malaysian were also analyzed, namely, bottled drinking water and tap water. The sources of these water samples are from groundwater and surface water (river), respectively. Results of hydrogen (ε 2 H) and oxygen (ε 18 O) isotope ratios of zam zam water from mecca are in the range of -13.62 % to -10.60 %, and -2.17 % to 0.06 %, respectively, while the hydrogen (ε 2 H) and oxygen (δ 18 O) isotope ratios of five samples from the bottled Zam Zam water are within the range of -50.74 % to -7.95 % to -5.39 %, respectively. The results from the measured values of all the water samples, and might be immensely useful for the purpose of regulatory monitoring of bottled water products. (author)

  6. Experimental assessment of the purity of α-cellulose produced by variations of the Brendel method: Implications for stable isotope (δ13C, δ18O) dendroclimatology

    Science.gov (United States)

    Brookman, Tom; Whittaker, Thomas

    2012-09-01

    Stable isotope dendroclimatology using α-cellulose has unique potential to deliver multimillennial-scale, sub-annually resolved, terrestrial climate records. However, lengthy processing and analytical methods often preclude such reconstructions. Variants of the Brendel extraction method have reduced these limitations, providing fast, easy methods of isolating α-cellulose in some species. Here, we investigate application of Standard Brendel (SBrendel) variants to resinous soft-woods by treating samples of kauri (Agathis australis), ponderosa pine (Pinus ponderosa) and huon pine (Lagarastrobus franklinii), varying reaction vessel, temperature, boiling time and reagent volume. Numerous samples were visibly `under-processed' and Fourier Transform infrared spectroscopic (FTIR) investigation showed absorption peaks at 1520 cm-1 and ˜1600 cm-1 in those fibers suggesting residual lignin and retained resin respectively. Replicate analyses of all samples processed at high temperature yielded consistent δ13C and δ18O despite color and spectral variations. Spectra and isotopic data revealed that α-cellulose δ13C can be altered during processing, most likely due to chemical contamination from insufficient acetone removal, but is not systematically affected by methodological variation. Reagent amount, temperature and extraction time all influence δ18O, however, and our results demonstrate that different species may require different processing methods. FTIR prior to isotopic analysis is a fast and cost effective way to determine α-cellulose extract purity. Furthermore, a systematic isotopic test such as we present here can also determine sensitivity of isotopic values to methodological variables. Without these tests, isotopic variability introduced by the method could obscure or `create' climatic signals within a data set.

  7. Water circulation control on carbonate-δ18O records in a low permeability clay formation and surrounding limestones: The Upper Dogger-Oxfordian sequence from the eastern Paris basin, France

    International Nuclear Information System (INIS)

    Lavastre, Veronique; Ader, Magali; Buschaert, Stephane; Petit, Eddy; Javoy, Marc

    2011-01-01

    Research highlights: → Up. Dog./Oxf. sequence is investigated for radioactive waste disposal feasibilities. → Marine carbonates suffered isotopic exchanges with meteoric water. → Modelling shows that very low W/R ratio can explain isotopic changes in clay layer. → Higher W/R ratio are needed to reach isotopic changes in carbonated layers. → Confirmed barrier property of clay layer was probably reached during early burial. - Abstract: Upper Dogger to Oxfordian Formations in the eastern part of the Paris basin (France) are currently being investigated by the French nuclear waste management agency (Andra), testing the feasibility of long-term deep nuclear waste disposal in the Callovo-Oxfordian claystones. Characterising the hydrogeological behaviour of the Callovo-Oxfordian claystones is, therefore, essential in evaluating its potential as a geological barrier. In order to evaluate and quantify water/rock interactions experienced over geological time by these Formations, bulk carbonate δ 13 C and δ 18 O were measured and calculations of water-rock ratios were used to explain carbonate-δ 18 O changes. Meteoric porewater and a maximum temperature reached of about 40 deg. C were considered. The Jurassic marine carbonate δ 13 C was preserved in the Callovo-Oxfordian claystones and in the overlying limestones (-0.28 per mille to 3.39 per mille/PDB), while the δ 18 O values are lower by 0-5 per mille (-6.25 per mille to -1.32 per mille/PDB). Calculations show that Upper Dogger and Oxfordian Limestone δ 18 O data: (i)have random-like distribution through theoretical δ 18 O-W/R curves and (ii)suggest that water/rock ratios (0.08-0.4) needed to explain δ 18 O changes are higher by a factor of about 2-20 compared to the present-day water/rock ratio. These features indicate advection in both aquifers. According to the history of the Paris basin, this hydrogeological behaviour could have been effective since Jurassic/Cretaceous transition times. Inversely, the

  8. Oxygen isotope effect in YBa2Cu3O7 prepared by burning YBa2Cu3 in 16O and 18O

    Science.gov (United States)

    Yvon, Pascal J.; Schwarz, R. B.; Pierce, C. B.; Bernardez, L.; Conners, A.; Meisenheimer, R.

    1989-04-01

    We prepared YBa2Cu3 powder by ball milling a 2:1 molar mixture of the intermetallics BaCu and CuY. We synthesized YBa2Cu3(16O)7-x and YBa2Cu3(18O)7-x by oxidizing the YBa2Cu3 powder in 16O and 18O. The 16O/18O ratios were determined by laser-ionization and sputtering-ionization mass spectroscopy. The YBa2Cu3(160)7-x sample had 99.8 at. %16O, and the YBa2Cu3(18O)7-x sample had 96.5 at. %18O. Susceptibility measurements of the superconducting transition temperature (Tc=91.7 K for 16O; half-point transition at 84 K show an isotope effect of 0.4+/-0.1 K.

  9. Minor elements, HREE and d18O distribution in UHP garnets from the Dora-Maira massif (western Alps)

    Science.gov (United States)

    Brunet, F.; Chazot, G.; Vielzeuf, D.; Chopin, C.

    2003-04-01

    The spatial distribution of minor elements, HREE and δ18O in garnet can be used as a probe of the availability and mobility of those elements and isotopes at the time of crystal growth, provided that the initial record was not significantly modified by intracrystalline diffusion and that growth took place under nearly constant pressure and temperature conditions. Garnets from three different Dora-Maira rock-types have been studied, (1) nearly pure pyrope (GT1) from the magnesian coesite-bearing quartzites, (2) almandine/pyrope dominant garnets (GT2) from jadeite-quartzite veins which crosscut the Mg-quartzite body, (3) almandine/grossular dominant garnets (GT3) from the country-rock gneiss, sampled in the vicinity of the quartzites. In GT1, minor elements are mainly Fe, Na and P. Na and P are incorporated according to a Na^+ + P5+ = Me2+ + Si4+ substitution with P_2O_5 contents up to 2000 to 2500 ppm. HREE concentrations obtained by LA-ICP-MS, vary by 2 orders of magnitude from core to rim. The δ18O ratio (Cameca 1270, Nancy), around 5 ppm (SMOW), is constant within error throughout the analysed crystals. In GT2, the situation is different since HREE concentrations appear remarkably constant within a given crystal and from one crystal to the other. In contrast with GT1, Na in GT2 is partly charge-balanced by yttrium incorporation. The δ18O ratio in GT2 of around 7 ppm is close to that encountered in GT3 (gneiss) between 7 and 8 ppm. In GT3, phosphorus content is close to detection limit (P_2O_5 below 300 ppm). HREE concentrations are highly variable from one crystal to the other and unfortunately, the size of garnet crystals does not allow profiling. Although δ18O ratio in garnet is imposed by the bulk-rock isotopic composition, HREE distribution is dominated by element availability through the fluid composition and/or absence/presence of accessory phases. The decrease in HREE and P concentration from GT1 cores to rims suggest that these elements are

  10. Measurement of the reaction {gamma}d {yields}pn{pi}{sup +}{pi}{sup -} at SAPHIR and investigation of the decay angular distribution of the {Delta}{sup ++}(1232) resonance; Messung der Reaktion {gamma}d {yields}pn{pi}{sup +}{pi}{sup -} an SAPHIR und Untersuchung der Zerfallswinkelverteilung der {Delta}{sup ++}(1232)-Resonanz

    Energy Technology Data Exchange (ETDEWEB)

    Schuetz, P.

    1993-03-01

    SAPHIR, a new experiment at the Bonn electron stretcher ring ELSA, started taking data in spring 1992. It was set up for the investigation of photon induced reactions with multiparticle final states. In the first part of this paper the special design of the target is described. It can be operated with liquefied hydrogen or deuterium and is placed in the middle of the central drift chamber. To project the surrounding chamber in case of a fracture of the target cell as safety system is installed. In addition two independent methods of monitoring the cell are procided. The first measurement was performed with a deuterium target at a photon energy range of E{sub {gamma}} = 500-700 MeV. In the second part of this paper first results of an analysis of the decay angular distribution of the {Delta}{sup ++}(1232) in the reaction {gamma}d {yields} n{Delta}{sup ++}{pi}{sup -} are presented. They are compared to old data from a hydrogen bubble chamber experiment and are discussed on the basis of a spectator model. (orig.) [Deutsch] Im Rahmen dieser Arbeit ist der Aufbau eines Fluessiggas-Targets beschrieben worden, das speziell fuer den Einsatz im SAPHIR-Detektor entwickelt worden ist. Es wurden Funktionen zur Ueberwachung der Targetzelle vorgestellt und ein Sicherheitssystem zum Schutz der zentralen Driftkammer, die das Target unmittelbar umgibt. Weiterhin ist in Simulationsrechnungen untersucht worden, welchen Einfluss die Konstruktion des Targetstreutopfes auf die Messung unterschiedlicher Reaktionen haben kann. Dabei sind bei 50% bis 70% der Ereignisse Treffer in den Aluminiumstuetzen des Targetstreutopfes aufgetreten. Diese starke Beeintraechtigung kann durch eine Neukonstruktion des Streutopfes und der Verwendung von z.B. Rohazell als Streutopffenster vermieden werden. Rohazell zeichnet sich durch eine hohe Festigkeit und grosse Strahlungslaenge aus. An der Neukonstruktion des Streutopfes wird z.Z. gearbeitet. Der zweite Teil der Arbeit beschreibt eine der ersten

  11. A 500-year seasonally resolved δ18O and δ13C, layer thickness and calcite aspect record from a speleothem deposited in the Han-sur-Lesse cave, Belgium

    Science.gov (United States)

    Van Rampelbergh, M.; Verheyden, S.; Allan, M.; Quinif, Y.; Cheng, H.; Edwards, L. R.; Keppens, E.; Claeys, P.

    2015-06-01

    Speleothem δ18O and δ13C signals enable climate reconstructions at high resolution. However, scarce decadal and seasonally resolved speleothem records are often difficult to interpret in terms of climate due to the multitude of factors that affect the proxy signals. In this paper, a fast-growing (up to 2 mm yr-1) seasonally laminated speleothem from the Han-sur-Lesse cave (Belgium) is analyzed for its δ18O and δ13C values, layer thickness and changes in calcite aspect. The studied record covers the period between AD 2001 and 1479 as indicated by layer counting and confirmed by 20 U / Th ages. The Proserpine proxies are seasonally biased and document drier (and colder) winters on multidecadal scales. Higher δ13C signals reflect increased prior calcite precipitation (PCP) and lower soil activity during drier (and colder) winters. Thinner layers and darker calcite relate to slower growth and exist during drier (and colder) winter periods. Exceptionally dry (and cold) winter periods occur from 1565 to 1610, at 1730, from 1770 to 1800, from 1810 to 1860, and from 1880 to 1895 and correspond to exceptionally cold periods in historical and instrumental records as well as European winter temperature reconstructions. More relative climate variations, during which the four measured proxies vary independently and display lower amplitude variations, occur between 1479 and 1565, between 1610 and 1730, and between 1730 and 1770. The winters during the first and last periods are interpreted as relatively wetter (and warmer) and correspond to warmer periods in historical data and in winter temperature reconstructions in Europe. The winters in the period between 1610 and 1730 are interpreted as relatively drier (and cooler) and correspond to generally colder conditions in Europe. Interpretation of the seasonal variations in δ18O and δ13C signals differs from that on a decadal and multidecadal scale. Seasonal δ18O variations reflect cave air temperature variations and

  12. Analysis of elastic scattering cross-section for 18O + 206Pb in the CRC formalism and dependence on the choice of double folding potential

    International Nuclear Information System (INIS)

    Sonika; Roy, B.J.; Parmar, A.; Jha, V.; Pal, U.K.; Pandit, S.K.; Parkar, V.V.; Ramachandran, K.; Mahata, K.; Pal, A.; Santra, S.; Mohanty, A.K.; Sinha, T.; Parihari, A.

    2014-01-01

    Measurement and detailed analysis of elastic scattering and inelastic excitations in 206 Pb( 18 O, 18 O) have been reported here. First, the elastic scattering cross-section was calculated with a bare double folded real potential. The DF potential consists of folding of a harmonic oscillator density distribution to simulate 18 O with the sum of two Fermi density distributions for the proton and neutron in 206 Pb with correct normalizations. Our measured higher energy data for the same system was first analyzed with this DF potential

  13. Enrichment of 15N and 18O by chemical exchange reactions between nitrogen oxides (NO, NO2) and aqueous nitric acid

    International Nuclear Information System (INIS)

    Abrudean, M.; Axente, D.; Baldea, A.

    1981-01-01

    The enrichment of 15 N and 18 O by chemical exchange in the NO, NO 2 -H 2 O, HNO 3 system is described. A laboratory experimental plant and a cascade for producing the two isotopes has been used. The production plant consists of two exchange columns for 15 N separation and two 18 O separation columns feeded with nitrogen oxides, depleted of 15 N, from the top of the first 15 N separation column. The by-products nitric acid and sulphuric acid, both depleted of 15 N and 18 O, are of commercial interest. (author)

  14. Inelastic scattering of antiprotons from 12C and 18O at 50 and 180 MeV

    International Nuclear Information System (INIS)

    Lemaire, M.C.; Birien, P.; Bruge, G.; Drake, D.M.; Garreta, D.; Janouin, S.; Legrand, D.; Mayer, B.; Pain, J.; Peng, J.C.

    1986-01-01

    The angular distributions of the inelastic scattering of antiprotons for a few collective states of 12 C and 18 O have been measured. They exhibit a diffractive pattern, typical of strong absorption. Coupled channel analysis of these data has been carried out. The derived multipole moments agree fairly well with those obtained with other probes. Microscopic calculations performed in the framework of the DWIA formalism, using either the Paris or the Dover-Richard Nanti N interaction are in good agreement with the data for the low-lying collective states. The present status of the experimental study of the unnatural parity levels is discussed. (orig.)

  15. Elastic electron scattering from 14N, 15N, 16O and 18O at small momentum transfer

    International Nuclear Information System (INIS)

    Schuetz, W.

    1973-01-01

    At the Darmstadt linear accelerator, cross-sections for the elastic scattering of electrons on 14 N and 16 O relative to the proton and on 15 N and 18 O relative to 14 N and 16 O were measured at energies 30 MeV 0 0 (q 2 -2 ). The experiments were done with gas targets, the target containers being thin-walled aluminium cylinders. The data were evaluated by means of the partial-wave method assuming a charge distribution according to the shell model. (orig./WL) [de

  16. Determination of Isotopic Abundance of 2H, 13C, 18O, and 37Cl in Biofield Energy Treated Dichlorophenol Isomers

    OpenAIRE

    Branton, Alice; Trivedi, Dahryn; Nayak, Gopal; Trivedi, Mahendra; Saikia, Gunin; Jana, Snehasis

    2016-01-01

    2,4-Dichlorophenol (2,4-DCP) and 2,6-dichlorophenol (2,6-DCP) are two isomers of dichlorophenols, have been used as preservative agents for wood, paints, vegetable fibers and as intermediates in the production of pharmaceuticals and dyes. The aim of the study was to evaluate the impact of biofield energy treatment on the isotopic abundance ratios of 2H/1H or 13C/12C, and 18O/16O or 37Cl/35Cl, in dichlorophenol isomers using gas chromatography-mass spectrometry (GC-MS). The 2,4-DCP and 2,6-DCP...

  17. Complete Measurement of Stable Isotopes in N2O (δ15N, δ15Nα, δ15Nβ, δ18O, δ17O) Using Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS)

    Science.gov (United States)

    Leen, J. B.; Gupta, M.

    2014-12-01

    nitrate in soil and groundwater and may be used to differentiate other sources of nitrate for which the range of Δ17O values is much smaller. By measuring δ15N, δ15Nα, δ15Nβ, δ18O and δ17O, our instrument will help researchers unravel the complicated nitrate mixing problem to determine the sources and sinks of nitrate pollution.

  18. Electrical transport properties of CoMn0.2−xGaxFe1.8O4 ferrites using complex impedance spectroscopy

    Directory of Open Access Journals (Sweden)

    Chien-Yie Tsay

    2016-05-01

    Full Text Available In this study, we report the influence of Ga content on the microstructural, magnetic, and AC impedance properties of Co-based ferrites with compositions of CoMn0.2−xGaxFe1.8O4 (x=0, 0.1, and 0.2 prepared by the solid-state reaction method. Experimental results showed that the as-prepared Co-based ferrites had a single-phase spinel structure; the Curie temperature of Co-based ferrites decreased with increasing Ga content. All ferrite samples exhibited a typical hysteresis behavior with good values of saturation magnetization at room temperature. The electrical properties of Co-based ferrites were investigated using complex impedance spectroscopy analysis in the frequency range of 100 kHz-50 MHz at temperatures of 150 to 250 oC. The impedance analysis revealed that the magnitudes of the real part (Z’ and the imaginary part (Z” of complex impedance decreased with increasing temperature. Only one semicircle was observed in each complex impedance plane plot, which revealed that the contribution to conductivity was from the grain boundaries. It was found that the relaxation time for the grain boundary (τgb also decreased with increasing temperature. The values of resistance for the grain boundary (Rgb significantly increased with increasing Ga content, which indicated that the incorporation of Ga into Co-based ferrites enhanced the electrical resistivity.

  19. Quantitative Proteomic Analysis of Mouse Embryonic Fibroblasts and Induced Pluripotent Stem Cells Using 16O /18O labeling

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xin; Tian, Changhai; Liu, Miao; Wang, Yongxiang; Tolmachev, Aleksey V.; Sharma, Seema; Yu, Fang; Fu, Kai; Zheng, Jialin; Ding, Shi-Jian

    2012-04-06

    Induced pluripotent stem cells (iPSC) hold great promise for regenerative medicine as well as for investigations into the pathogenesis and treatment of various diseases. Understanding of key intracellular signaling pathways and protein targets that control development of iPSC from somatic cells is essential for designing new approaches to improve reprogramming efficiency. Here we report the development and application of an integrated quantitative proteomics platform for investigating differences in protein expressions between mouse embryonic fibroblasts (MEF) and MEF-derived iPSC. This platform consists of 16O/18O labeling, multidimensional peptide separation coupled with tandem mass spectrometry, and data analysis with UNiquant software. Using this platform a total of 2,481 proteins were identified and quantified from the 16O/18O-labeled MEF-iPSC proteome mixtures with a false discovery rate of 0.01. Among them, 218 proteins were significantly upregulated, while 247 proteins were significantly downregulated in iPSC compared to MEF. Many nuclear proteins, including Hdac1, Dnmt1, Pcna, Ccnd1, Smarcc1, and subunits in DNA replication and RNA polymerase II complex were found to be enhanced in iPSC. Protein network analysis revealed that Pcna functions as a hub orchestrating complicated mechanisms including DNA replication, epigenetic inheritance (Dnmt1) and chromatin remodeling (Smarcc1) to reprogram MEF and maintain stemness of iPSC.

  20. Mixing and evaporation processes in an inverse estuary inferred from δ2H and δ18O

    Science.gov (United States)

    Corlis, Nicholas J.; Herbert Veeh, H.; Dighton, John C.; Herczeg, Andrew L.

    2003-05-01

    We have measured δ2H and δ18O in Spencer Gulf, South Australia, an inverse estuary with a salinity gradient from 36‰ near its entrance to about 45‰ at its head. We show that a simple evaporation model of seawater under ambient conditions, aided by its long residence time in Spencer Gulf, can account for the major features of the non-linear distribution pattern of δ2H with respect to salinity, at least in the restricted part of the gulf. In the more exposed part of the gulf, the δ/ S pattern appears to be governed primarily by mixing processes between inflowing shelf water and outflowing high salinity gulf water. These data provide direct support for the oceanographic model of Spencer Gulf previously proposed by other workers. Although the observed δ/ S relationship here is non-linear and hence in notable contrast to the linear δ/ S relationship in the Red Sea, the slopes of δ2H vs. δ18O are comparable, indicating that the isotopic enrichments in both marginal seas are governed by similar climatic conditions with evaporation exceeding precipitation.

  1. Analysis of products of thymine irradiated by 18O8+ ion beam in N2O saturated aqueous solution

    International Nuclear Information System (INIS)

    Cai Xichen; Wei Zengquan; Li Wenjian; Liang Jianping; Li Qiang

    1999-01-01

    Some methods of capillary gas chromatography, such as GC, GC-MS GC-FT-IR, are used to analyze the products of thymine irradiated by 18 O 8+ ion beam in N 2 O saturated aqueous solution. From the results of GC-MS the molecular weight of products can be determined, and from the results of GC-FT-IR some molecular structure information of products can be obtained. By this way the products, 5,6-Dihydro-thymine, 5-Hydroxyl-5-Methylhydantoin, 5-Hydroxyl-6-Hydro-thymine, 5-Hydro-6-Hydroxyl thymine, 5-Hydroxymethyluracil, Trans-Thymine glycol, Cis-Thymine glycol and dimers are determined without separation of them from samples. Though these products are as same as those products of thymine irradiated by γ rays in N 2 O saturated aqueous solution, the mechanism of thymine irradiated by heavy ion beam in aqueous solution is different from that by γ rays. The main products of thymine irradiated by 18 O 8+ ion beam in N 2 O saturated aqueous solution are hydroxyl adducts at 5-6 band of thymine, while the main products of thymine irradiated by γ ray in N 2 O saturated aqueous solution are dimers of thymine

  2. δ13C and δ18O measurements of carbonate rocks using Cavity Ring-Down Spectroscopy

    Science.gov (United States)

    Lucic, G.; Kim-Hak, D.; Curtis, J. H.

    2017-12-01

    We present a novel, user friendly and cost effective method for the analysis of δ13C and δ18O in CO2 gas obtained from acid digestion of carbonate rocks. 2 to 3 milligrams of pure carbonate, ground to a powder, is digested in a pre-evacuated glass vial using 100% phosphoric acid at 70° C. Vials with the reacted samples are then loaded onto an automated carousel sampler where produced CO2 gas in the headspace is extracted and sent to a Picarro CRDS isotopic C and O analyzer. Once loaded onto the carousel, 49 samples may be analyzed automatically at a rate of one sample every 15 minutes. δ13C and δ18O of the sample are reported in real time with a precision of 0.2 and 0.4 per mil, respectively. The portability and simplicity of the autosampler and CRDS setup opens up potential for permanent and mobile deployments, enabling near-realtime sampling feedback in the lab or on the go in the field. Consumable and operating costs are small when compared to other technology in use, making the CRDS-Carbonate system suitable for large and small research labs. Finally, we present a summary results from a series of validation tests in which standards and natural carbonate rock samples were analyzed and compared to traditional Kiel-IRMS results.

  3. δ(15)N and δ(18)O Reveal the Sources of Nitrate-Nitrogen in Urban Residential Stormwater Runoff.

    Science.gov (United States)

    Yang, Yun-Ya; Toor, Gurpal S

    2016-03-15

    Nitrogen (N) sources are widely distributed in the complex urban environment. High-resolution data elucidating N sources in the residential catchments are not available. We used stable isotopes of N and oxygen (O) of nitrate (δ(18)O-NO3(-) and δ(15)N-NO3(-)) along with δ(18)O and hydrogen (δD) of water (H2O) to understand the sources and transformations of N in residential stormwater runoff. Stormwater runoff samples were collected over 25 stormwater events at 5 min intervals using an autosampler installed at the residential catchment outlet pipe that drained 31 low-density homes with a total drainage area of 0.11 km(2). Bayesian mixing model results indicated that atmospheric deposition (range 43-71%) and chemical N fertilizers (range stormwater runoff and that there was a continuum of source changes during the stormwater events. Further, the NO3-N transport in the stormwater runoff from the residential catchment was driven by mixing of multiple sources and biotic (i.e., nitrification) processes. This work suggests that a better understanding of N transport and sources is needed to reduce N export and improve water quality in urban water systems.

  4. High precision measurement by mass spectrometry of isotopic ratios δ13C and δ18O of carbon dioxide

    International Nuclear Information System (INIS)

    Bourg, Chr.; Ciais, Ph.

    1998-02-01

    Carbon dioxide (CO 2 ) is the second natural greenhouse gas in the Earth's atmosphere, after vapor water. Its concentration levels have been increasing by 25% due to human activities over the past 200 years, thus increasing the radiative forcing at the surface and potentially including major climate change for the next centuries. It is of primary importance to better quantify the role of carbon contained into the oceans and the land biota in moderating the anthropic perturbation. To do so, 13 C and 18 O isotopes are unique tools which allow to estimate indirectly the terrestrial CO 2 fluxes based on atmospheric measurements. The present reports describes the experimental set-up used at the CFR-LMCE laboratory to measure the 13 C and 18 O natural abundance in atmospheric carbon dioxide. This technique requires high levels of both precision and accuracy because the geochemical signal nevertheless consists of very small changes in isotopic composition (on the order of 0.01 permits). Also, given the large number of samples to analyses routinely, it must be run in an automatic mode. Our experiment design consists of 'extraction line' where CO 2 is separated cryogenically from the air, which is coupled to a (Finnigan MAT 252) mass spectrometer. (authors)

  5. Study of some excited states in 21Ne-21Na, 18O-18F and 15N-15O nuclei

    International Nuclear Information System (INIS)

    Drain, D.

    1977-01-01

    The study of 21 Ne- 21 Na, 18 O- 18 F and 15 N- 15 O nuclei was performed through proton capture and transfer reactions and allows to determine the spins and parities of some excited states, give the gamma deexcitation schemes of these levels, compute the neutron and proton reduced width γ 2 sub(n) and γ 2 sub(p). The levels studied are: in 21 Na 4.15 20 Ne(p,p), (p,p'), (p,p'γ) and (pγ) reactions) and in 21 Ne: E(exc)=4.73, 5.69 and 5.78 MeV ( 20 Ne (p,p) reaction); in 18 O: E(exc) 17 O(d,p) reaction); in 15 O: 8.92 MeV doublet and 8.98 MeV level (angular correlation 14 N(p,γγ) and in 15 N: 9.05 14 N(d,p) reaction). A comparison with theoretical results is discussed and analog states are pointed out [fr

  6. Mean proloculus size, delta super(13) C and delta super(18) O variations in recent benthic foraminifera from the west coast of India and their climatic implications

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Sarkar, A.

    The interrelationship between mean proloculus size (MPS), delta super(18) O and delta super(13) C vatiations in benthic foraminiferal species Rotalidium annectens and their relation with temperature (T) and salinity (S) have been studied in samples...

  7. Using nitrogen stable isotope ratios ({delta}{sup 15}N) of macroalgae to determine the effectiveness of sewage upgrades: changes in the extent of sewage plumes over four years in Moreton Bay, Australia

    Energy Technology Data Exchange (ETDEWEB)

    Costanzo, Simon D. [National Research Centre for Environmental Toxicology, University of Queensland, 39 Kessels Road, Coopers Plains, QLD 4108 (Australia)]. E-mail: s.costanzo@uq.edu.au; Udy, James [Marine Botany, Centre for Marine Studies, University of Queensland, 4072 (Australia); Longstaff, Ben [Environmental Protection Agency, 80 Meiers Road, Indooroopilly, QLD 4058 (Australia); Jones, Adrian [University of Maryland Center for Environmental Science, P.O. Box 775, Cambridge, MD 21613, USA (United States)

    2005-07-01

    Nitrogen loading to aquatic ecosystems from sewage is recognised worldwide as a growing problem. The use of nitrogen stable isotopes as a means of discerning sewage nitrogen in the environment has been used annually by the Ecosystem Health Monitoring Program in Moreton Bay (Australia) since 1997 when the technique was first developed. This ('sewage plume mapping') technique, which measures the {delta}{sup 15}N isotopic signature of the red macroalga Catenella nipae after incubation in situ, has demonstrated a large reduction in the magnitude and spatial extent of sewage nitrogen within Moreton Bay over the past 5 years. This observed reduction coincides with considerable upgrades to the nitrogen removal efficacy at several sewage treatment plants within the region. This paper describes the observed changes and evaluates whether they can be attributed to the treatment upgrades.

  8. A 500 year seasonally resolved δ18O and δ13C, layer thickness and calcite fabric record from a speleothem deposited in equilibrium of the Han-sur-Lesse cave, Belgium

    Science.gov (United States)

    Van Rampelbergh, M.; Verheyden, S.; Allan, M.; Quinif, Y.; Cheng, H.; Edwards, L.; Keppens, E.; Claeys, P.

    2014-10-01

    Speleothem δ18O and δ13C signals have already proven to enable climate reconstructions at high resolution. However, seasonally resolved speleothem records are still scarce and often difficult to interpret in terms of climate due to the multitude of factors that can affect the proxy signals. In this paper, a fast growing (up to 2 mm yr-1) seasonally laminated speleothem from the Han-sur-Lesse cave (Belgium) is analyzed for its δ18O and δ13C values, layer thickness and changes in calcite fabric. The studied part of the speleothem covers the most recent 500 years as indicated by layer counting and confirmed by 20 U/Th-ages. Epikarst recharge occurs mainly in winter and lesser during spring and fall. a good correlation can be established between lower winter temperatures and lower winter precipitation (DJF) based on the measured data by the Belgian meteorological institute since 1833 indicating that a dry winter is also a cold winter. Colder and dryer winters cause lower winter recharge and generally drier conditions in the cave. Lower winter recharge decreases the amount of isotopically light (δ18O) winter precipitation added to the epikarst in comparison to the heavier spring and fall waters, which leads to a net increase in δ18O value of the water in the epikarst. Increased δ18O values in the Proserpine are consequently interpreted to reflect colder and dryer winters. Higher δ13C signals are interpreted to reflect increased prior calcite precipitation (PCP) due to colder and dryer winters, when recharge is lower. Thinner layers and darker calcite relate to slower growth and occur when drip rates are low and when the drip water calcium ion concentration is low due to increased PCP, both caused by lower recharge during periods with colder and dryer winters. Exceptionally cold and dry winters cause the drip discharge to decrease under a certain threshold value inducing anomalies in the measured proxy records. Such anomalies occur from 1565 to 1610, from 1770 to

  9. Hydrogeological and hydrochemical investigation of groundwater using environmental isotopes (18O, 2H, 3H, 14C) and chemical tracers: a case study of the intermediate aquifer, Sfax, southeastern Tunisia

    Science.gov (United States)

    Ayadi, Rahma; Trabelsi, Rim; Zouari, Kamel; Saibi, Hakim; Itoi, Ryuichi; Khanfir, Hafedh

    2017-12-01

    Major element concentrations and stable (δ18O and δ2H) and radiogenic (3H and 14C) isotopes in groundwater have proved useful tracers for understanding the geochemical processes that control groundwater mineralization and for identifying recharge sources in the semi-arid region of Sfax (southeastern Tunisia). Major-ion chemical data indicate that the origins of the salinity in the groundwater are the water-rock interactions, mainly the dissolution of evaporitic minerals, as well as the cation exchange with clay minerals. The δ18O and δ2H relationships suggest variations in groundwater recharge mechanisms. Strong evaporation during recharge with limited rapid water infiltration is evident in the groundwater of the intermediate aquifer. The mixing with old groundwater in some areas explains the low stable isotope values of some groundwater samples. Groundwaters from the intermediate aquifer are classified into two main water types: Ca-Na-SO4 and Ca-Na-Cl-SO4. The high nitrate concentrations suggest an anthropogenic source of nitrogen contamination caused by intensive agricultural activities in the area. The stable isotopic signatures reveal three water groups: non-evaporated waters that indicate recharge by recent infiltrated water; evaporated waters that are characterized by relatively enriched δ18O and δ2H contents; and mixed groundwater (old/recent) or ancient groundwater, characterized by their depleted isotopic composition. Tritium data support the existence of recent limited recharge; however, other low tritium values are indicative of pre-nuclear recharge and/or mixing between pre-nuclear and contemporaneous recharge. The carbon-14 activities indicate that the groundwaters were mostly recharged under different climatic conditions during the cooler periods of the late Pleistocene and Holocene.

  10. Late Glacial temperature and precipitation changes in the lowland Neotropics by tandem measurement of δ 18O in biogenic carbonate and gypsum hydration water

    Science.gov (United States)

    Hodell, David A.; Turchyn, Alexandra V.; Wiseman, Camilla J.; Escobar, Jaime; Curtis, Jason H.; Brenner, Mark; Gilli, Adrian; Mueller, Andreas D.; Anselmetti, Flavio; Ariztegui, Daniel; Brown, Erik T.

    2012-01-01

    We applied a new method to reconstruct paleotemperature in the tropics during the last deglaciation by measuring oxygen isotopes of co-occurring gypsum hydration water and biogenic carbonate in sediment cores from two lakes on the Yucatan Peninsula. Oxygen and hydrogen isotope values of interstitial and gypsum hydration water indicate that the crystallization water preserves the isotopic signal of the lake water, and has not undergone post-depositional isotopic exchange with sediment pore water. The estimated lake water δ18O is combined with carbonate δ18O to calculate paleotemperature. Three paired measurements of 1200-yr-old gypsum and gastropod aragonite from Lake Chichancanab, Mexico, yielded a mean temperature of 26 °C (range 23-29.5 °C), which is consistent with the mean and range of mean annual temperatures (MAT) in the region today. Paired measurements of ostracods, gastropods, and gypsum hydration water samples were measured in cores from Lake Petén Itzá, Guatemala, spanning the Late Glacial and early Holocene period (18.5-10.4 ka). The lowest recorded temperatures occurred at the start of Heinrich Stadial (HS) 1 at 18.5 ka. Inferred temperatures from benthic ostracods ranged from 16 to 20 °C during HS 1, which is 6-10 °C cooler than MAT in the region today, whereas temperatures derived from shallow-water gastropods were generally warmer (20-25 °C), reflecting epilimnetic temperatures. The derived temperatures support previous findings of greater tropical cooling on land in Central America during the Late Glacial than indicated by nearby marine records. Temperature increased in two steps during the last deglaciation. The first occurred during the Bolling-Allerod (B-A; from 14.7 to 13 ka) when temperature rose to 20-24 °C towards the end of this period. The second step occurred at 10.4 ka near the beginning of the Holocene when ostracod-inferred temperature rose to 26 °C, reflecting modern hypolimnetic temperature set during winter, whereas

  11. Hydrochemical and isotopic (2H, 18O and 37Cl) constraints on evolution of geothermal water in coastal plain of Southwestern Guangdong Province, China

    Science.gov (United States)

    Chen, Liuzhu; Ma, Teng; Du, Yao; Xiao, Cong; Chen, Xinming; Liu, Cunfu; Wang, Yanxin

    2016-05-01

    Geothermal energy is abundant in Guangdong Province of China, however, majority of it is still unexploited. To take full advantage of this energy, it is essential to know the information of geothermal system. Here, physical parameters such as pH and temperature, major ion (Na+, Ca2 +, Mg2 +, Cl-, SO42 - and HCO3-), trace elements (Br-, Sr2 +, Li+ and B3 +) and stable isotopes (2H, 18O and 37Cl) in geothermal water, non-geothermal water (river water, cold groundwater) and seawater were used to identify the origin and evolution of geothermal water in coastal plain of Southwest of Guangdong. Two separate groups of geothermal water have been identified in study area. Group A, located in inland of study area, is characterized by Na+ and HCO3-. Group B, located in coastal area, is characterized by Na+ and Cl-. The relationships of components vs. Cl for different water samples clearly suggest the hydrochemical differences caused by mixing with seawater and water-rock interactions. It's evident that water-rock interactions under high temperature make a significant contribution to hydrochemistry of geothermal water for both Group A and Group B. Besides, seawater also plays an important role during geothermal water evolution for Group B. Mixing ratios of seawater with geothermal water for Group B are calculated by Cl and Br binary diagram, the estimated results show that about < 1% to < 35% of seawater has mixed into geothermal water, and seawater might get into the geothermal system by deep faults. Molar Na/Cl ratios also support these two processes. Geothermal and non-geothermal water samples plot around GMWL in the δ2H vs. δ18O diagram, indicating that these samples have a predominant origin from meteoric water. Most of geothermal water samples display δ37Cl values between those of the non-geothermal water and seawater samples, further reveals three sources of elements supply for geothermal water, including atmospheric deposition, bedrocks and seawater, which show a

  12. Modelling (18)O2 and (16)O2 unidirectional fluxes in plants. IV: role of conductance and laws of its regulation in C3 plants.

    Science.gov (United States)

    André, Marcel J

    2013-08-01

    Numerous studies focus on the measurement of conductances for CO2 transfer in plants and especially on their regulatory effects on photosynthesis. Measurement accuracy is strongly dependent on the model used and on the knowledge of the flow of photochemical energy generated by light in chloroplasts. The only accurate and precise method to quantify the linear electron flux (responsible for the production of reductive energy) is the direct measurement of O2 evolution, by (18)O2 labelling and mass spectrometry. The sharing of this energy between the carboxylation (P) and the oxygenation of photorespiration (PR) depends on the plant specificity factor (Sp) and on the corresponding atmospheric concentrations of CO2 and O2 (André, 2013). The concept of plant specificity factor simplifies the equations of the model. It gives a new expression of the effect of the conductance (g) between atmosphere and chloroplasts. Its quantitative effect on photosynthesis is easy to understand because it intervenes in the ratio of the plant specificity factor (Sp) to the specificity of Rubisco (Sr). Using this 'simple' model with the data of (18)O2 experiments, the calculation of conductance variations in response to CO2 and light was carried out. The good fitting of experimental data of O2 and CO2 exchanges confirms the validity of the simple model. The calculation of conductance variation during the increase of external CO2 concentration reveals a linear law of regulation between external and internal CO2 concentrations. During CO2 variations, the effects of g regulation tend to maintain a higher level of oxygenation (PR) in expense of a better carboxylation (P). Contrary to CO2, the variation of O2 creates a negative feedback effect compatible with a stabilization of atmospheric O2. The regulation of g amplifies this result. The effect of light in combination with CO2 is more complex. Below 800μmolquantam(-2)s(-1) the ratio PR/P is maintained unchangeable in expense of carboxylation

  13. Geochemistry of the stable isotopes of silicon

    Energy Technology Data Exchange (ETDEWEB)

    Douthitt, C B [California Inst. of Tech., Pasadena (USA). Div. of Geological and Planetary Sciences

    1982-08-01

    One hundred thirty two new measurements of the relative abundances of the stable isotopes of silicon in terrestrial materials are presented. The total variation of delta/sup 30/Si found is 6.2 parts per thousand, centered on the mean of terrestrial mafic and ultramafic igneous rocks, delta/sup 30/Si = -0.4 parts per thousand. Igneous rocks show limited variation; coexisting minerals exhibit small, systematic silicon isotopic fractionations that are roughly 1/3 the magnitude of concomitant oxygen isotopic fractionations at 1150/sup 0/C. In both igneous minerals and rocks, delta/sup 30/Si shows a positive correlation with silicon content, as does delta/sup 18/O. Opal from both sponge spicules and sinters is light, with delta/sup 30/Si = -2.3 and -1.4 parts per thousand respectively. Large delta/sup 30/Si values of both positive and negative sign are reported for the first time from clay minerals, opaline phytoliths, and authigenic quartz. All highly fractionated samples were precipitated from solution at low temperatures; however, aqueous silicon is not measurably fractionated relative to quartz at equilibrium. A kinetic isotope fractionation of approximately 3.5 parts per thousand is postulated to occur during the low temperature precipitation of opal and, possibly, poorly ordered phyllosilicates, with the silicate phase being enriched in /sup 28/Si. This fractionation, coupled with a Rayleigh precipitation model, is capable of explaining most non-magmatic delta/sup 30/Si variations.

  14. Comparison between IRMS and CRDS methods in the determination of isotopic ratios 2H/1H and 18O/16O in water

    International Nuclear Information System (INIS)

    Santos, T. H. R.; Zucchi, M. R.; Lemaire, T.; Azevedo, A. E. G.

    2013-01-01

    Traditionally, the method used for measuring the isotope ratios is the Isotope Ratio Mass Spectrometers (IRMS). A new method has been used to determine the isotopic abundances, the Cavity Ring-Down Spectroscopy (CRDS). It consists of a technique of direct absorption, of high sensitivity, which is based on measuring the absorption ratio, as a function of time, of the light confined in a high finesse optical cavity, instead of the magnitude of light beam absorption. The values of 18 O/ 16 O and D/H ratios are determined with respect to international standards VSMOW, GISP and SLAP from the International Atomic Energy Agency (IAEA). In this work, the IRMS and CRDS techniques are compared, verifying that the CRDS technique is promising and has some advantages compared to IRMS. It uses a smaller amount of sample, the isotope measurements are made simultaneously from the steam, reducing the analysis time. It also shows good reproducibility and accuracy, and it does not require a preliminary sample preparation.

  15. Measurement of 18O + 10B fusion cross section and construction of a position sensitive ionization chamber

    International Nuclear Information System (INIS)

    Added, N.

    1987-01-01

    The 18 O + 10 B fusion reaction has been investigated within the bombarding energy range of 29,0 MeV lab 0 lab 0 angular range. For this purpose, a high resolution position sensitive ionization chamber has been developed and constructed. Experimental results compared to model predictions and experimental systematics found in the literature allows to reject compound nucleus limitation to the fusion cross section up to energies as high as five times the coulomb barrier. Statistical model fits to the residues elementary distributions reveal a quite difuse partial fusion cross section in the angular momentum space. Systematic analysis of fusion barrier height (V B ) and radius (R B ) for neighbouring nuclei point out the importance of the nuclear matter difuseness in the competition between the fusion and quasi-direct process. Calculations within this framework were performed. (author) [pt

  16. Neutron--proton radius differences and isovector deformations from π+ and π- inelastic scattering from 18O

    International Nuclear Information System (INIS)

    Iversen, S.G.

    1979-05-01

    Angular distributions were measured for elastic and inelastic scattering of 164 and 230 MeV π +- from 18 O. Angular distributions for elastic scattering and for excitation of the 2 1 + transition at 1.98 MeV, the 3 1 - transition at 5.10 MeV, and an unresolved triplet of states consisting of the 4 1 + at 3.56 MeV, the 0 2 + at 3.63 MeV, and the 2 2 + at 3.92 MeV are presented. The angular ranges covered are 17.5 to 80 0 for T/sub π/ = 164 MeV and 17.5 to 70 0 for T/sub π/ = 230 MeV. In addition 1 1 - transition at 4.45 MeV and several transitions at excitation energies above 6 MeV, but detailed analysis of these transitions was not undertaken. 123 references

  17. Stable isotope compositions of quartz pebbles and their fluid inclusions as tracers of sediment provenance: Implications for gold- and uranium-bearing quartz pebble conglomerates

    Energy Technology Data Exchange (ETDEWEB)

    Vennemann, T.W.; Kesler, S.E.; O' Neil, J.R. (Univ. of Michigan, Ann Arbor (United States))

    1992-09-01

    Oxygen isotope compositions of pebbles from late Archean to paleo-Proterozoic gold- and/or uranium-bearing oligomictic quartz pebble conglomerates of the Witwatersrand district, South Africa, and Huronian Supergroup, Canada, were determined in an attempt to define the nature of the source terrain. The [delta][sup 18]O values of quartz pebbles within any one sample typically vary by [approximately] 4[per thousand] or more, but occasionally by as much as 8[per thousand], even for adjacent pebbles within the same hand specimen. In addition, adjacent quartz pebbles of widely contrasting [delta][sup 18]O values also preserve distinct isotopic signatures of their fluid inclusions. This overall heterogeneity suggests that the pebbles did not undergo significant oxygen isotope exchange after incorporation in the conglomerates. Therefore, oxygen isotope analyses of such quartz pebbles, in combination with a detailed investigation of their mineral and fluid inclusions, can provide a useful method for characterizing pebble populations and hence dominant sediment source modes. Comparison of values found in this study with [delta][sup 18]O values of quartz from Archean granites, pegmatites, and mesothermal greenstone gold veins, i.e., [delta][sup 18]O values of sources commonly proposed for the conglomerate ores, suggests that uranium is derived from a granitic source, whereas gold has a mesothermal greenstone gold source. Low [delta][sup 18]O values of chert pebbles (9[per thousand] to 11.5[per thousand]) relative to those expected for Archean and Proterozoic marine cherts (commonly [ge] 17[per thousand]) effectively exclude marine cherts, and therefore, auriferous iron formations and exhalatives, as likely sources of gold.

  18. Modelling (18)O2 and (16)O2 unidirectional fluxes in plants. III: fitting of experimental data by a simple model.

    Science.gov (United States)

    André, Marcel J

    2013-08-01

    Photosynthetic assimilation of CO2 in plants results in the balance between the photochemical energy developed by light in chloroplasts, and the consumption of that energy by the oxygenation processes, mainly the photorespiration in C3 plants. The analysis of classical biological models shows the difficulties to bring to fore the oxygenation rate due to the photorespiration pathway. As for other parameters, the most important key point is the estimation of the electron transport rate (ETR or J), i.e. the flux of biochemical energy, which is shared between the reductive and oxidative cycles of carbon. The only reliable method to quantify the linear electron flux responsible for the production of reductive energy is to directly measure the O2 evolution by (18)O2 labelling and mass spectrometry. The hypothesis that the respective rates of reductive and oxidative cycles of carbon are only determined by the kinetic parameters of Rubisco, the respective concentrations of CO2 and O2 at the Rubisco site and the available electron transport rate, ultimately leads to propose new expressions of biochemical model equations. The modelling of (18)O2 and (16)O2 unidirectional fluxes in plants shows that a simple model can fit the photosynthetic and photorespiration exchanges for a wide range of environmental conditions. Its originality is to express the carboxylation and the oxygenation as a function of external gas concentrations, by the definition of a plant specificity factor Sp that mimics the internal reactions of Rubisco in plants. The difference between the specificity factors of plant (Sp) and of Rubisco (Sr) is directly related to the conductance values to CO2 transfer between the atmosphere and the Rubisco site. This clearly illustrates that the values and the variation of conductance are much more important, in higher C3 plants, than the small variations of the Rubisco specificity factor. The simple model systematically expresses the reciprocal variations of

  19. The earliest low and high δ18O caldera-forming eruptions of the Yellowstone plume: Implications for the 30–40 Ma Oregon calderas and speculations on plume-triggered delaminations

    Directory of Open Access Journals (Sweden)

    Angela Nicole Seligman

    2014-11-01

    Full Text Available We present new isotopic and trace element data for four eruptive centers in Oregon: Wildcat Mountain (40 Ma, Crooked River (32–28 Ma, Tower Mountain (32 Ma, and Mohawk River (32 Ma. The first three calderas are located too far east to be sourced through renewed subduction of the Farallon slab following accretion of the Yellowstone-produced Siletzia terrane at ~50 Ma. Basalts of the three eastern eruptive centers yield high Nb/Yb and Th/Yb ratios, indicating an enriched sublithospheric mantle source, while Mohawk River yields trace element and isotopic (δ18O and εHf values that correlate with its location above a subduction zone. The voluminous rhyolitic tuffs and lavas of Crooked River (41 x 27 km have δ18Ozircon values that include seven low δ18Ozircon units (1.8–4.5 ‰, one high δ18Ozircon unit (7.4–8.8 ‰, and two units with heterogeneous zircons (2.0–9.0 ‰, similar to younger Yellowstone-Snake River Plain rhyolites. In order to produce these low δ18O values, a large heat source, widespread hydrothermal circulation, and repeated remelting are all required. In contrast, Wildcat Mountain and Tower Mountain rocks yield high δ18Ozircon values (6.4–7.9 ‰ and normal to low εHfi values (5.2–12.6, indicating crustal melting of high-δ18O supracrustal rocks. We propose that these calderas were produced by the first appearance of the Yellowstone plume east of the Cascadia subduction zone, which is supported by plate reconstructions that put the Yellowstone plume under Crooked River at 32–28 Ma. Given the eastern location of these calderas along the suture of the accreted Siletzia terrane and North America, we suggest that the Yellowstone hotspot is directly responsible for magmatism at Crooked River, and for plume-assisted delamination of portions of the edge of the Blue Mountains that produced the Tower Mountain magmas, while the older Wildcat Mountain magmas are related to suture zone instabilities that were created

  20. LIMS for Lasers 2015 for achieving long-term accuracy and precision of δ2H, δ17O, and δ18O of waters using laser absorption spectrometry

    Science.gov (United States)

    Coplen, Tyler B.; Wassenaar, Leonard I

    2015-01-01

    RationaleAlthough laser absorption spectrometry (LAS) instrumentation is easy to use, its incorporation into laboratory operations is not easy, owing to extensive offline manipulation of comma-separated-values files for outlier detection, between-sample memory correction, nonlinearity (δ-variation with water amount) correction, drift correction, normalization to VSMOW-SLAP scales, and difficulty in performing long-term QA/QC audits.MethodsA Microsoft Access relational-database application, LIMS (Laboratory Information Management System) for Lasers 2015, was developed. It automates LAS data corrections and manages clients, projects, samples, instrument-sample lists, and triple-isotope (δ17O, δ18O, and δ2H values) instrumental data for liquid-water samples. It enables users to (1) graphically evaluate sample injections for variable water yields and high isotope-delta variance; (2) correct for between-sample carryover, instrumental drift, and δ nonlinearity; and (3) normalize final results to VSMOW-SLAP scales.ResultsCost-free LIMS for Lasers 2015 enables users to obtain improved δ17O, δ18O, and δ2H values with liquid-water LAS instruments, even those with under-performing syringes. For example, LAS δ2HVSMOW measurements of USGS50 Lake Kyoga (Uganda) water using an under-performing syringe having ±10 % variation in water concentration gave +31.7 ± 1.6 ‰ (2-σ standard deviation), compared with the reference value of +32.8 ± 0.4 ‰, after correction for variation in δ value with water concentration, between-sample memory, and normalization to the VSMOW-SLAP scale.ConclusionsLIMS for Lasers 2015 enables users to create systematic, well-founded instrument templates, import δ2H, δ17O, and δ18O results, evaluate performance with automatic graphical plots, correct for δ nonlinearity due to variable water concentration, correct for between-sample memory, adjust for drift, perform VSMOW-SLAP normalization, and perform long-term QA/QC audits

  1. Electron spray ionization mass spectrometry and 2D 31P NMR for monitoring 18O/16O isotope exchange and turnover rates of metabolic oligophosphates

    International Nuclear Information System (INIS)

    Nemutlu, Emirhan; Juranic, Nenad; Macura, Slobodan; Zhang, Song; Terzic, Andre; Dzeja, Petras P.; Ward, Lawrence E.; Dutta, Tumpa; Nair, K.S.

    2012-01-01

    A new method was here developed for the determination of 18 O-labeling ratios in metabolic oligophosphates, such as ATP, at different phosphoryl moieties (α-, β-, and γ-ATP) using sensitive and rapid electrospray ionization mass spectrometry (ESI-MS). The ESI-MS-based method for monitoring of 18 O/ 16 O exchange was validated with gas chromatography-mass spectrometry and 2D 31 P NMR correlation spectroscopy, the current standard methods in labeling studies. Significant correlation was found between isotopomer selective 2D 31 P NMR spectroscopy and isotopomer less selective ESI-MS method. Results demonstrate that ESI-MS provides a robust analytical platform for simultaneous determination of levels, 18 O-labeling kinetics and turnover rates of α-, β-, and γ-phosphoryls in ATP molecule. Such method is advantageous for large scale dynamic phosphometabolomic profiling of metabolic networks and acquiring information on the status of probed cellular energetic system. (orig.)

  2. Unstable relationships between tree ring δ18O and climate variables over southwestern China: possible impacts from increasing central Pacific SSTs

    Science.gov (United States)

    An, Wenling; Liu, Xiaohong; Hou, Shugui; Zeng, Xiaomin; Sun, Weizhen; Wang, Wenzhi; Wang, Yu; Xu, Guobao; Ren, Jiawen

    2018-05-01

    In this study, we investigated the potential influence of central and eastern Pacific sea surface temperatures (SSTs) on the unstable relationship between earlywood δ18O and climatic factors in the southwestern China from 1902 to 2005. The results show that the strength of the climate signals recorded in the earlywood δ18O series has declined since the late 1970s. This reduction in signal strength may have been caused by the changes in the local hydroclimate, which is associated with the increasing SSTs in the central Pacific Ocean over recent decades. Alongside these increasing SSTs in the central Pacific, southwestern China has experienced more droughts, as well as more severe droughts through the late spring and early summer during the central Pacific (CP) El Niño years than during the eastern Pacific (EP) El Niño years in recent decades. This increased drought frequency may have weakened the response of earlywood δ18O to climate variables.

  3. Direct analysis of δ2H and δ18O in natural and enriched human urine using laser-based, Off-Axis Integrated Cavity Output Spectroscopy

    Science.gov (United States)

    Berman, Elena S.F.; Fortsona, Susan L.; Snaith, Steven P.; Gupta, Manish; Baer, Douglas S.; Chery, Isabelle; Blanc, Stephane; Melanson, Edward L.; Thomson, Peter J; Speakman, John R.

    2012-01-01

    The stable isotopes of hydrogen (δ2H) and oxygen (δ18O) in human urine are measured during studies of total energy expenditure by the doubly labeled water method, measurement of total body water, and measurement of insulin resistance by glucose disposal among other applications. An ultrasensitive laser absorption spectrometer based on off-axis integrated cavity output spectroscopy was demonstrated for simple and inexpensive measurement of stable isotopes in natural isotopic abundance and isotopically enriched human urine. Preparation of urine for analysis was simple and rapid (approx. 25 samples per hour), requiring no decolorizing or distillation steps. Analysis schemes were demonstrated to address sample-to-sample memory while still allowing analysis of 45 natural or 30 enriched urine samples per day. The instrument was linear over a wide range of water isotopes (δ2H = −454 to +1702 ‰ and δ18O= −58.3 to +265 ‰). Measurements of human urine were precise to better than 0.65 ‰ 1σ for δ2H and 0.09 ‰ 1σ for δ18O for natural urines, 1.1 ‰ 1σ for δ2H and 0.13 ‰ 1σ for δ18O for low enriched urines, and 1.0 ‰ 1σ for δ2H and 0.08 ‰ 1σ for δ18O for high enriched urines. Furthermore, the accuracy of the isotope measurements of human urines was verified to better than ±0.81 ‰ in δ2H and ±0.13 ‰ in δ18O (average deviation) against three independent IRMS laboratories. The ability to immediately and inexpensively measure the stable isotopes of water in human urine is expected to increase the number and variety of experiments which can be undertaken. PMID:23075099

  4. Report on the supply and demand of 18O enriched water. Ad hoc committee of the North American Society for the Study of Obesity, 21 January 1999

    International Nuclear Information System (INIS)

    1999-01-01

    Oxygen-18 is a stable isotope that is used as a tracer for several biomedical applications. The two primary applications are the study of organismal energy expenditure and organ specific utilization of glucose. The former uses 18 O along with deuterium to measure carbon dioxide production of free-living animals and humans. Total energy expenditure is calculated from carbon dioxide production using the standard equations of indirect calorimetry. The later uses 18 O as a precursor for the production of 18 F, a radionuclide that is incorporated into glucose homologues and injected into the circulating blood. When the glucose homologues are taken up by an organ (usually brain), the organ can be imaged using positron emission tomography (PET). Both of these techniques have become major research and, in the case of PET, diagnostic tools during the last decade. This growth in the use of these tools has increased the world-wide demand for 18 O in the form of water. In 1998, this demand could not be met by suppliers and significant delivery delays have been encountered by many investigators and clinicians. Some suppliers are quoting delivery delays of a year. These delays have disrupted on-going research and delayed the start of new projects. The shortage has resulted in a price increase of nearly 50% in 18 O water. The disruption of 18 O supply in 1998 is the second such disruption in the past decade. Commercial suppliers could not provide sufficient product in late 1990 following the forced closure of the US government production facility at Los Alamos Laboratory. Delivery delays lasted throughout 1991. In August of 1998, the council of the North American Association for the Study of Obesity formed an ad hoc committee to gather information regarding the supply and demand for 18 O and to investigate potential solutions to the problem

  5. Quantitation of peptides and proteins by matrix-assisted laser desorption/ionization mass spectrometry using (18)O-labeled internal standards

    DEFF Research Database (Denmark)

    Mirgorodskaya, O A; Kozmin, Y P; Titov, M I

    2000-01-01

    A method for quantitating proteins and peptides in the low picomole and sub-picomole range has been developed using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) with internal (18)O-labeled standards. A simple procedure is proposed to produce such internal standards for...... inhibitor, were quantified by MALDI-time-of-flight (TOF) mass spectrometry.......A method for quantitating proteins and peptides in the low picomole and sub-picomole range has been developed using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) with internal (18)O-labeled standards. A simple procedure is proposed to produce such internal standards...

  6. Impact of traffic on δ15N, δ13C and δ18O of needles and annual tree rings of Norway spruce (Picea abies L.

    Directory of Open Access Journals (Sweden)

    Guerrieri MR

    2006-01-01

    Full Text Available Increase of nitrogen depositions, as oxidized (NOx and reduced (NHx compounds, has important implications on ecosystem nitrogen cycle. NOx comes predominantly from fossil fuel combustion in car engines and industrial processes, while agricultural activities (cattle farming, fertilizations are the main sources for NHx emissions. Such fertilisations could stimulate growth and, therefore, productivity of forests, especially in temperate forests, where nitrogen is a limiting factor. On the other hand an excess of nitrogen can lead to an acidification of the soil and have a negative impact on the microbial fauna and structure of plants. NOx and NHx depositions can be separated with the help of stable isotopes with different 15N-values reported for NOx originating from combustion sources. Consequently it was observed that the nitrogen isotopic composition of the vegetation reflects the isotopic signature of nitrogen sources. Our preliminary results on needles of Norway spruce trees exposed to NOx emissions along a transect perpendicular to a highway close to Faido and Brittnau show a clear isotopic enrichment in 15N in trees growing closer to traffic pollution, indicating an uptake of atmospheric nitrogen by stomatal pathway. Carbon and oxygen isotopic composition measured in tree rings reveals the physiological response in plants. Trees more exposed to air pollution from traffic show an increase in δ13C and δ18O in tree rings, since mid sixties next to Erstfeld. This could mean a higher photosynthetic activity, enhanced by NOx traffic emissions, under low or not changed stomatal conductance. Our results confirm that stable isotopes of carbon, oxygen and nitrogen measured in needles and tree rings represent an important tool to monitor the impact of NOx load on tree physiology.

  7. Final report on fourth interlaboratory comparison exercise for δ2H and δ18O analysis of water samples (WICO2011)

    International Nuclear Information System (INIS)

    Ahmad, M.; Aggarwal, P.; Duren, M. van; Poltenstein, L.; Araguas, L.; Kurttas, T.; Wassenaar, L.I.

    2012-01-01

    The IAEA Isotope Hydrology Laboratory organized the fourth interlaboratory comparison exercise for laboratories engaged in routine analysis of hydrogen and oxygen stable isotope composition of water samples in 2011. Three similar exercises were carried out in 1995, in 1999 and in 2002. However, the tradition of IAEA water stable isotope inter-laboratory comparison is much older. Two interlaboratory comparison trials for isotope hydrology laboratories were carried out in the sixties and seventies, which revealed problems with use of the NBS-1 international standard; these data were used to calibrate the newly produced primary reference materials VSMOW and SLAP. The WICO2011 exercise was announced in February 2011 on the internet, via the ISOGEOCHEM news group of Isogeochemistry and by email to all participants of the former intercomparisons. Altogether 174 laboratories expressed interest to participate in the exercise. Four water samples prepared and calibrated at the IAEA Isotope Hydrology Laboratory were labelled IAEA-OH-13 to IAEA-OH-16, which are referred to in this report as OH-13 to OH-16. By the end of the reporting deadline (the end of August 2011) altogether 137 laboratories from 53 countries had submitted 172 datasets back to the IAEA on the oxygen and hydrogen isotopic composition of these water samples. The four water samples cover the range of δ18O and δ2H values typical for the majority of natural waters. The samples were bottled from 30 L stainless steel storage barrels into 30 mL securely-capped brown glass bottles, serially numbered at the time of filling. Each laboratory received a set of four samples with a corresponding code. This code (assigned randomly) forms the Identification (ID) code used throughout the exercise and in the tables and graphs of this report for each laboratory. The ID code is not related to the order of the list of participating laboratories. The identity of participating laboratories will not be revealed unless each

  8. Arctic plant ecophysiology and water source utilization in response to altered snow: isotopic (δ18O and δ2H) evidence for meltwater subsidies to deciduous shrubs.

    Science.gov (United States)

    Jespersen, R Gus; Leffler, A Joshua; Oberbauer, Steven F; Welker, Jeffrey M

    2018-06-28

    Warming-linked woody shrub expansion in the Arctic has critical consequences for ecosystem processes and climate feedbacks. The snow-shrub interaction model has been widely implicated in observed Arctic shrub increases, yet equivocal experimental results regarding nutrient-related components of this model have highlighted the need for a consideration of the increased meltwater predicted in expanding shrub stands. We used a 22-year snow manipulation experiment to simultaneously address the unexplored role of snow meltwater in arctic plant ecophysiology and nutrient-related components of the snow-shrub hypothesis. We coupled measurements of leaf-level gas exchange and leaf tissue chemistry (%N and δ 13 C) with an analysis of stable isotopes (δ 18 O and δ 2 H) in soil water, precipitation, and stem water. In deeper snow areas photosynthesis, conductance, and leaf N increased and δ 13 C values decreased in the deciduous shrubs, Betula nana and Salix pulchra, and the graminoid, Eriophorum vaginatum, with the strongest treatment effects observed in deciduous shrubs, consistent with predictions of the snow-shrub hypothesis. We also found that deciduous shrubs, especially S. pulchra, obtained much of their water from snow melt early in the growing season (40-50%), more than either E. vaginatum or the evergreen shrub, Rhododendron tomentosum (Ledum palustre). This result provides the basis for adding a meltwater-focused feedback loop to the snow-shrub interaction model of shrub expansion in the Arctic. Our results highlight the critical role of winter snow in the ecophysiology of Arctic plants, particularly deciduous shrubs, and underline the importance of understanding how global warming will affect the Arctic winter snowpack.

  9. Isotope tracing (29Si and 18O) of the alteration mechanisms of the French glass 'SON68' used for the storage of nuclear waste

    International Nuclear Information System (INIS)

    Valle, N.

    2001-01-01

    This study aims to enhance our understanding of the mechanisms of aqueous corrosion of the glasses used for the storage of nuclear waste. Glass samples 'SON68', doped with a different rare earth element (La, Ce or Nd), were altered simultaneously with water enriched in 29 Si and 18 O, throughout a period of 20 months. The aim of such isotope tracing was (i) to follow the 'real' exchanges between glass and solution and (ii) to understand the reactions involving Si-O bonds in the leached layer during alteration. Leachates were analyzed by ICP-MS and -AES, and elemental and isotopic variations in the altered glass layer were measured by ion-probe, using a depth profiling technique. Elemental analyses enabled the distribution of the elements in the two layers of altered glass (phyllosilicates and gel) to be established, and the results reveal a selective partitioning of elements between the two layers. Isotopic analyses of altered layers and leachates allowed phyllosilicates to be distinguished from gel, and suggest two different mechanisms of formation. Whilst phyllosilicates grow on the surface of the glass by a mechanism of precipitation, gel is formed by a succession of hydrolysis / condensation reactions taking place mainly at the gel / pristine glass interface. This gel is formed by the in situ rearrangement of hydrated species, without reaching equilibrium with the solution. Moreover, an experimental technique has been developed enabling one to trace the transport of silicon from the solution into the altered glasses, under an isotopic gradient. Diffusion profiles, obtained by ion-probe, have been modeled and have allowed the determination of the apparent silicon diffusion coefficient (DSi) in gels. Therefore, our experiments have permitted the quantification of the influence of both the alteration conditions (dynamic or static tests) and the solution composition on the value of DSi. (author)

  10. Diagnosing Atmospheric Influences on the Interannual 18O/16O Variations in Western U.S. Precipitation

    Directory of Open Access Journals (Sweden)

    Kei Yoshimura

    2013-07-01

    Full Text Available Many climate proxies in geological archives are dependent on the isotopic content of precipitation (δ18Op, which over sub-annual timescales has been linked to temperature, condensation height, atmospheric circulation, and post-condensation exchanges in the western U.S. However, many proxies do not resolve temporal changes finer than interannual-scales. This study explores causes of the interannual variations in δ18Op within the western U.S. Simulations with the Isotope-incorporated Global Spectral Model (IsoGSM revealed an amplifying influence of post-condensation exchanges (i.e., raindrop evaporation and vapor equilibration on interannual δ18Op variations throughout the western U.S. Mid-latitude and subtropical vapor tagging simulations showed that the influence of moisture advection on δ18Op was relatively strong in the Pacific Northwest, but weak over the rest of the western U.S. The vapor tags correlated well with interannual variations in the 18O/16O composition of vapor, an indication that isotopes in vapor trace atmospheric circulation. However, vertical-tagging simulations revealed a strong influence of condensation height on δ18Op in California. In the interior of the western U.S., a strong temperature effect was found only after annual mean temperatures were weighted by monthly precipitation totals. These multiple influences on δ18Op complicate interpretations of western U.S. climate proxies that are derived from isotopes in precipitation.

  11. Leaf water 18 O and 2 H enrichment along vertical canopy profiles in a broadleaved and a conifer forest tree.

    Science.gov (United States)

    Bögelein, Rebekka; Thomas, Frank M; Kahmen, Ansgar

    2017-07-01

    Distinguishing meteorological and plant-mediated drivers of leaf water isotopic enrichment is prerequisite for ecological interpretations of stable hydrogen and oxygen isotopes in plant tissue. We measured input and leaf water δ 2 H and δ 18 O as well as micrometeorological and leaf morpho-physiological variables along a vertical gradient in a mature angiosperm (European beech) and gymnosperm (Douglas fir) tree. We used these variables and different enrichment models to quantify the influence of Péclet and non-steady state effects and of the biophysical drivers on leaf water enrichment. The two-pool model accurately described the diurnal variation of leaf water enrichment. The estimated unenriched water fraction was linked to leaf dry matter content across the canopy heights. Non-steady state effects and reduced stomatal conductance caused a higher enrichment of Douglas fir compared to beech leaf water. A dynamic effect analyses revealed that the light-induced vertical gradients of stomatal conductance and leaf temperature outbalanced each other in their effects on evaporative enrichment. We conclude that neither vertical canopy gradients nor the Péclet effect is important for estimates and interpretation of isotopic leaf water enrichment in hypostomatous trees. Contrarily, species-specific non-steady state effects and leaf temperatures as well as the water vapour isotope composition need careful consideration. © 2017 John Wiley & Sons Ltd.

  12. Fission fragments mass distributions of nuclei populated by the multinucleon transfer channels of the 18O+232Th reaction

    Directory of Open Access Journals (Sweden)

    R. Léguillon

    2016-10-01

    Full Text Available It is shown that the multinucleon transfer reactions is a powerful tool to study fission of exotic neutron-rich actinide nuclei, which cannot be accessed by particle-capture or heavy-ion fusion reactions. In this work, multinucleon transfer channels of the 18O+232Th reaction are used to study fission of fourteen nuclei 231,232,233,234Th, 232,233,234,235,236Pa, and 234,235,236,237,238U. Identification of fissioning nuclei and of their excitation energy is performed on an event-by-event basis, through the measurement of outgoing ejectile particle in coincidence with fission fragments. Fission fragment mass distributions are measured for each transfer channel, in selected bins of excitation energy. In particular, the mass distributions of 231,234Th and 234,235,236Pa are measured for the first time. Predominantly asymmetric fission is observed at low excitation energies for all studied cases, with a gradual increase of the symmetric mode towards higher excitation energy. The experimental distributions are found to be in general agreement with predictions of the fluctuation–dissipation model.

  13. Study of ternary-component bismuth molybdate catalysts by 18O2 tracer in the oxidation of propylene to acrolein

    International Nuclear Information System (INIS)

    Ueda, W.; Moro-oka, Y.; Ikawa, T.

    1981-01-01

    Participation of lattice oxide ions of ternary-component bismuth molybdate catalysts M-Bi-Mo-O (M = Ni, Co, Mg, Mn, Ca, Sr, Ba, and Pb) was investigated using the 18 O 2 tracer in the selective oxidation of propylene to acrolein. The participation of the lattice oxide ions in the oxidation is prominent on every catalyst but the extent of the participation varies significantly depending on the structure of the catalyst. Only lattice oxide ions in the bismuth molybdate phase are incorporated into the oxidized products on the catalysts (M = Ni, Co, Mg, and Mn) where M have smaller ionic radius than Bi 3+ ; catalyst particles are composed of a shell of bismuth molybdates and a core of MMoO 4 . On the other hand, whole oxide ions in the active particles are involved in the oxidation on catalysts having a scheelite-type structure (M = Ca, Sr, Ba, and Pb) where M has a comparable ionic radius to Bi 3+

  14. The physical hydrology of magmatic-hydrothermal systems: High-resolution 18O records of magmatic-meteoric water interaction from the Yankee Lode tin deposit (Mole Granite, Australia)

    Science.gov (United States)

    Fekete, Szandra; Weis, Philipp; Driesner, Thomas; Heinrich, Christoph A.; Baumgartner, Lukas; Bouvier, Anne-Sophie

    2016-04-01

    Magmatic-hydrothermal ore deposits are important economic Cu, Au, Mo and Sn resources (Sillitoe, 2010, Kesler, 1994). The ore formation is a result of superimposed enrichment processes and metals can precipitate due to fluid-rock interaction and/or temperature drop caused by convection or mixing with meteoric fluid (Heinrich and Candela 2014). Microthermometry and LA-ICP MS trace element analyses of fluid inclusions of a well-characterized quartz sample from the Yankee Lode quartz-cassiterite vein deposit (Mole Granite, Australia) suggest that tin precipitation was driven by dilution of hot magmatic water by meteoric fluids (Audétat et al.1998). High resolution in situ oxygen isotope measurements of quartz have the potential to detect changing fluid sources during the evolution of a hydrothermal system. We analyzed the euhedral growth zones of this previously well-studied quartz sample. Growth temperatures are provided by Audétat et al. (1998) and Audétat (1999). Calculated δ 18O values of the quartz- and/or cassiterite-precipitating fluid show significant variability through the zoned crystal. The first and second quartz generations (Q1 and Q2) were precipitated from a fluid of magmatic isotopic composition with δ 18O values of ˜ 8 - 10 ‰. δ 18O values of Q3- and tourmaline-precipitating fluids show a transition from magmatic δ 18O values of ˜ 8 ‰ to ˜ -5 ‰. The outermost quartz-chlorite-muscovite zone was precipitated from a fluid with a significant meteoric water component reflected by very light δ 18O values of about -15 ‰ which is consistent with values found by previous studies (Sun and Eadington, 1987) using conventional O-isotope analysis of veins in the distal halo of the granite intrusion. Intense incursion of meteoric water during Q3 precipitation (light δ 18O values) agrees with the main ore formation event, though the first occurrence of cassiterite is linked to Q2 precipitating fluid with magmatic-like isotope signature. This

  15. Imprints of climate signals in a 204 year 18O tree-ring record of Nothofagus pumilio from Perito Moreno Glacier, southern Patagonia (50°S).

    Science.gov (United States)

    Grießinger, Jussi; Langhamer, Lukas; Schneider, Christoph; Saß, Björn-Lukas; Steger, David; Skvarca, Pedro; Braun, Matthias H.; Meier, Wolfgang J.-H.; Srur, Ana M.; Hochreuther, Philipp

    2018-04-01

    A 204 year-long record of 18O in tree-ring cellulose of southern beech (Nothofagus pumilio) from a site near Perito Moreno Glacier (50°S) in southern Patagonia was established to assess its potential for a climate reconstruction. The annually resolved oxygen isotope chronology is built out of seven individual tree-ring 18O series with a significant mean inter-series correlation (r = 0.61) and is the first of its kind located in Southern America south of 50°S. Over a common period from 1960 to 2013 of available stationary and high-resolution gridded CRU TS v. 4.01 data, the 18O chronology exhibits a strong sensitivity towards hydroclimatic as well as temperature parameters as revealed by correlation analyses. Among these, positive correlations with maximum temperature in the first part of the summer season (CRU rONDJ = 0.51, pAmerica. The modulation of positive and negative anomalies within this series can be interlinked to changes in moisture source origin as revealed by backward trajectory modeling. Additionally, these anomalies can be directly associated to positive or negative phases of the Antarctic Oscillation Index (AAOI) and therefore the strength of the Westerlies. Aligned by the analysis on the influence of different main weather types on the 18O chronology it is shown that such time-series hold the potential to additionally capture their respective influence and change during the last centuries.

  16. In folio study of carbonic anhydrase and Rubisco activities in higher C{sub 3} plants using {sup 18}O and mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Peltier, G.; Despax, V.; Dimon, B.; Rumeau, D.; Tourneux, C.

    1994-12-31

    This document studies the effects of a mild water stress and carbonic anhydrase activity by ethoxyzolamide (EZA) on the diffusion of CO{sub 2} in leaves, by {sup 18}O labelling of O{sub 2} and of CO{sub 2} associated to mass spectrometry. (A.B.). 5 refs., 2 figs.

  17. Identifying residence times and streamflow generation processes using ?18O and ?2H in meso-scale catchments in the Abay/Upper Blue Nile, Ethiopia

    NARCIS (Netherlands)

    Teklaeb, S.; Wenninger, J.W.; Uhlenbrook, S.

    2013-01-01

    Measurements of the stable isotopes oxygen-18 (18O) and deuterium (2H) were carried out in two meso-scale catchments, Chemoga (358 km2) and Jedeb (296 km2) south of Lake Tana, Abay/Upper Blue Nile basin, Ethiopia. The region is of paramount importance for the water resources in the Nile basin.

  18. A temporal stable isotopic (d18O, dD, d-excess) comparison in glacier meltwater streams, Taylor Valley, Antarctica

    Science.gov (United States)

    In this paper, we describe the importance of hyporheic dynamics within Andersen Creek and Von Guerard Stream, Taylor Valley, Antarctica, from the 2010-11 melt season using natural tracers. Water collection started at flow onset and continued, with weekly hyporheic zone sampling. The water d18O and d...

  19. Low-res d15N and d18O of O2 in the WAIS Divide 06A Deep Core, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set is a low-resolution set of measurements of d15N of N2 and d18O of O2, along with dO2/N and dAr/N2 supporting data, in the WAIS Divide 3405 m long ice...

  20. Daily variations of delta 18O and delta D in daily samplings of air water vapour and rain water in the Amazon Basin

    International Nuclear Information System (INIS)

    Matsui, E.; Salati, E.; Ribeiro, M.N.G.; Tancredi, A.C.F.N.S.; Reis, C.M. dos

    1984-01-01

    The movement of rain water in the soil from 0 to 120 cm depth using delta 18 O weekly variations is studied. A study of the delta D variability in water vapour and rain water samples during precipitation was also done, the samples being collected a 3 minute intervals from the beginning to the end of precipitation. (M.A.C.) [pt

  1. Punta Pitt Stable Isotope and Ion Data (delta 18O, delta 13C, Cd/Ca, Mn/Ca) for 1936 to 1982.5

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — File contains data presented by Shen et al. (1992a). Table includes d18O, d13C, Cd/Ca, Mn/Ca, and Ba/Ca data from a 2m coral head and, for comparison, SST records...

  2. Climatology of the Eastern Arabian Sea during the last glacial cycle reconstructed from paired measurement of foraminiferal delta sup(18)O and Mg/Ca

    Digital Repository Service at National Institute of Oceanography (India)

    Banakar, V.K.; Mahesh, B.S.; Burr, G.; Chodankar, A

    Paired measurements of Mg/Ca and delta sup(18)O of Globigerenoides sacculifer from an Eastern Arabian Sea (EAS) sediment core indicate that sea-surface temperature (SST) varied within 2 degrees C and sea-surface salinity within 2 psu during the last...

  3. Facile hydrothermal synthesis of ultrasmall W{sub 18}O{sub 49} nanoparticles and studies of their photocatalytic activity towards degradation of methylene blue

    Energy Technology Data Exchange (ETDEWEB)

    Bhuyan, Bishal; Paul, Bappi [Department of Chemistry, National Institute of Technology, Silchar, Silchar, 788010, Assam (India); Dhar, Siddhartha Sankar, E-mail: ssd_iitg@hotmail.com [Department of Chemistry, National Institute of Technology, Silchar, Silchar, 788010, Assam (India); Vadivel, Sethumathavan [Department of Chemistry, PSG College of Technology, Coimbatore, Tamilnadu, 641004 (India)

    2017-02-15

    Uniformly dispersed ultrasmall tungsten oxide nanoparticles (W{sub 18}O{sub 49}) of sizes around 5–7 nm were synthesized using tungsten hexachloride as tungsten precursor and octadecylamine (ODA) as surfactant and as well as reducing agent. The as-synthesized nanoparticles (NPs) were characterized thoroughly by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) and N{sub 2} adsorption desorption isotherm (BET). From the XRD patterns, formation of monoclinic primitive phase of W{sub 18}O{sub 49} was observed while TEM images showed well dispersed particles of sizes 5–7 nm. The surface area of the W{sub 18}O{sub 49} NPs was found to be 27.17 m{sup 2} g{sup −1}. These ultrasmall W{sub 18}O{sub 49} NPs have been studied as photocatalysts for the first time in the degradation of methylene blue (MB). The photocatalytic activity was evaluated in oxidative degradation of MB with H{sub 2}O{sub 2} under solar irradiation. The particles exhibited pronounced activity in degradation of MB as well as efficient recyclability. The small band gap energy of W{sub 18}O{sub 49} NPs and their large surface area helps in the production of higher electron (e{sup −}) and hole (h{sup +}) pairs which in a way also prevents the e{sup −} and h{sup +} pairs from recombination within the nanoparticles. This greatly improves and enhances the photocatalytic activity of our synthesized nanoparticles. - Highlights: • Ultrasmall W{sub 18}O{sub 49} NPs were synthesized by a facile hydrothermal route. • Octadecylamine was used as both capping and reducing agent. • The XRD patterns revealed formation of monoclinic primitive phase of W{sub 18}O{sub 49}. • The TEM images showed that the material were well dispersed with sizes from 5 to 7 nm. • The synthesized NPs exhibited pronounced photocatalytic activity towards MB degradation.

  4. Use of Multiple Linear Regression Method for Modelling Seasonal Changes in Stable Isotopes of 18O and 2H in 30 Pouns in Gilan Province

    Directory of Open Access Journals (Sweden)

    M.A. Mousavi Shalmani

    2014-08-01

    Full Text Available In order to assessment of water quality and characterize seasonal variation in 18O and 2H in relation with different chemical and physiographical parameters and modelling of effective parameters, an study was conducted during 2010 to 2011 in 30 different ponds in the north of Iran. Samples were collected at three different seasons and analysed for chemical and isotopic components. Data shows that highest amounts of δ18O and δ2H were recorded in the summer (-1.15‰ and -12.11‰ and the lowest amounts were seen in the winter (-7.50‰ and -47.32‰ respectively. Data also reveals that there is significant increase in d-excess during spring and summer in ponds 20, 21, 22, 24, 25 and 26. We can conclude that residual surface runoff (from upper lands is an important source of water to transfer soluble salts in to these ponds. In this respect, high retention time may be the main reason for movements of light isotopes in to the ponds. This has led d-excess of pond 12 even greater in summer than winter. This could be an acceptable reason for ponds 25 and 26 (Siyahkal county with highest amount of d-excess and lowest amounts of δ18O and δ2H. It seems light water pumped from groundwater wells with minor source of salt (originated from sea deep percolation in to the ponds, could may be another reason for significant decrease in the heavy isotopes of water (18O and 2H for ponds 2, 12, 14 and 25 from spring to summer. Overall conclusion of multiple linear regression test indicate that firstly from 30 variables (under investigation only a few cases can be used for identifying of changes in 18O and 2H by applications. Secondly, among the variables (studied, phytoplankton content was a common factor for interpretation of 18O and 2H during spring and summer, and also total period (during a year. Thirdly, the use of water in the spring was recommended for sampling, for 18O and 2H interpretation compared with other seasons. This is because of function can be

  5. Isotopically (δ13C and δ18O) heavy volcanic plumes from Central Andean volcanoes: a field study

    Science.gov (United States)

    Schipper, C. Ian; Moussallam, Yves; Curtis, Aaron; Peters, Nial; Barnie, Talfan; Bani, Philipson; Jost, H. J.; Hamilton, Doug; Aiuppa, Alessandro; Tamburello, Giancarlo; Giudice, Gaetano

    2017-08-01

    Stable isotopes of carbon and oxygen in volcanic gases are key tracers of volatile transfer between Earth's interior and atmosphere. Although important, these data are available for few volcanoes because they have traditionally been difficult to obtain and are usually measured on gas samples collected from fumaroles. We present new field measurements of bulk plume composition and stable isotopes (δ13CCO2 and δ18OH2O+CO2) carried out at three northern Chilean volcanoes using MultiGAS and isotope ratio infrared spectroscopy. Carbon and oxygen in magmatic gas plumes of Lastarria and Isluga volcanoes have δ13C in CO2 of +0.76‰ to +0.77‰ (VPDB), similar to slab carbonate; and δ18O in the H2O + CO2 system ranging from +12.2‰ to +20.7‰ (VSMOW), suggesting significant contributions from altered slab pore water and carbonate. The hydrothermal plume at Tacora has lower δ13CCO2 of -3.2‰ and δ18OH2O+CO2 of +7.0‰, reflecting various scrubbing, kinetic fractionation, and contamination processes. We show the isotopic characterization of volcanic gases in the field to be a practical complement to traditional sampling methods, with the potential to remove sampling bias that is a risk when only a few samples from accessible fumaroles are used to characterize a given volcano's volatile output. Our results indicate that there is a previously unrecognized, relatively heavy isotopic signature to bulk volcanic gas plumes in the Central Andes, which can be attributed to a strong influence from components of the subducting slab, but may also reflect some local crustal contamination. The techniques we describe open new avenues for quantifying the roles that subduction zones and arc volcanoes play in the global carbon cycle.

  6. Oxygen determination in materials by {sup 18}O(p,αγ){sup 15}N nuclear reaction

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Sanjiv, E-mail: sanjucccm@rediffmail.com [National Centre for Compositional Characterization of Materials, BARC, ECIL Post, Hyderabad 500062 (India); Sunitha, Y.; Reddy, G.L.N.; Sukumar, A.A.; Ramana, J.V.; Sarkar, A. [National Centre for Compositional Characterization of Materials, BARC, ECIL Post, Hyderabad 500062 (India); Verma, Rakesh [Analytical Chemistry Division, BARC, Mumbai 400085 (India)

    2016-07-01

    The paper presents a proton induced γ-ray emission method based on {sup 18}O(p,αγ){sup 15}N nuclear reaction to determine bulk oxygen in materials. The determination involves the measurement of 5.27 MeV γ-rays emitted following the de-excitation of {sup 15}N nuclei. A description of the energetics of the reaction is given to provide an insight into the origin of 5.27 MeV γ-rays. In addition, thick target γ-ray yields and the limits of detection are measured to ascertain the analytical potential of the reaction. The thick-target γ-ray yields are measured with a high purity germanium detector and a bismuth germanate detector at 0° as well as 90° angles in 3.0–4.2 MeV proton energy region. The best limit of detection of about 1.3 at.% is achieved at 4.2 MeV proton energy for measurements at 0° as well 90° angles with the bismuth germanate detector while the uncertainty in quantitative analysis is <8%. The reaction has a probing depth of several tens of microns. Interferences can arise from fluorine due to the occurrence of {sup 19}F(p,αγ){sup 16}O reaction that emits 6–7 MeV γ-rays. The analytical potential of the methodology is demonstrated by determining oxygen in several oxide as well as non-oxide materials.

  7. Discovery of undefined protein cross-linking chemistry: a comprehensive methodology utilizing 18O-labeling and mass spectrometry.

    Science.gov (United States)

    Liu, Min; Zhang, Zhongqi; Zang, Tianzhu; Spahr, Chris; Cheetham, Janet; Ren, Da; Zhou, Zhaohui Sunny

    2013-06-18

    Characterization of protein cross-linking, particularly without prior knowledge of the chemical nature and site of cross-linking, poses a significant challenge, because of their intrinsic structural complexity and the lack of a comprehensive analytical approach. Toward this end, we have developed a generally applicable workflow-XChem-Finder-that involves four stages: (1) detection of cross-linked peptides via (18)O-labeling at C-termini; (2) determination of the putative partial sequences of each cross-linked peptide pair using a fragment ion mass database search against known protein sequences coupled with a de novo sequence tag search; (3) extension to full sequences based on protease specificity, the unique combination of mass, and other constraints; and (4) deduction of cross-linking chemistry and site. The mass difference between the sum of two putative full-length peptides and the cross-linked peptide provides the formulas (elemental composition analysis) for the functional groups involved in each cross-linking. Combined with sequence restraint from MS/MS data, plausible cross-linking chemistry and site were inferred, and ultimately confirmed, by matching with all data. Applying our approach to a stressed IgG2 antibody, 10 cross-linked peptides were discovered and found to be connected via thioethers originating from disulfides at locations that had not been previously recognized. Furthermore, once the cross-link chemistry was revealed, a targeted cross-link search yielded 4 additional cross-linked peptides that all contain the C-terminus of the light chain.

  8. Synthesis of porous LiFe0.2Mn1.8O4 with high performance for lithium-ion battery

    International Nuclear Information System (INIS)

    Shi, Yishan; Zhu, Shenmin; Zhu, Chengling; Li, Yao; Chen, Zhixin; Zhang, Di

    2015-01-01

    Highlights: • Porous LiFe 0.2 Mn 1.8 O 4 was fabricated with P123 as a template through a nitrate decomposition method • A high rate capacity and cycling stability were demonstrated when used as cathode in LIBs • This strategy is expected to fabricate other multiple metal oxides with porous structures - Abstract: A facile and effective route was developed for the fabrication of LiFe 0.2 Mn 1.8 O 4 with porous structures by using Pluronic P-123 as a soft template, based on a nitrate decomposition method. The resultant LiFe 0.2 Mn 1.8 O 4 was characterized by XRD, SEM, as well as N 2 adsorption/desorption measurements which showed a porous structure with a pore size centered at 20 nm. When used as cathode materials in lithium battery, the as-synthesized LiFe 0.2 Mn 1.8 O 4 exhibited a discharge capacity of 122 mAh g −1 at 1 C and 102 mAh g −1 at 5 C. Moreover, after 500 cycles, the capacity retention (108 mAh g −1 ) reached 88% of the initial capacity at 1 C. As compared with conventional cathode LiMn 2 O 4 , the high performance is believed to originate from the combined effects of porous structure, iron doping and highly crystalline nature of the obtained LiFe 0.2 Mn 1.8 O 4 . This strategy is expected to allow the fabrication of other multiple metal oxides with porous structures for high performance cathode materials

  9. Tree ring δ18O reveals no long-term change of atmospheric water demand since 1800 in the northern Great Hinggan Mountains, China

    Science.gov (United States)

    Liu, Xiaohong; Zhang, Xuanwen; Zhao, Liangju; Xu, Guobao; Wang, Lixin; Sun, Weizhen; Zhang, Qiuliang; Wang, Wenzhi; Zeng, Xiaomin; Wu, Guoju

    2017-07-01

    Global warming will significantly increase transpirational water demand, which could dramatically affect plant physiology and carbon and water budgets. Tree ring δ18O is a potential index of the leaf-to-air vapor-pressure deficit (VPD) and therefore has great potential for long-term climatic reconstruction. Here we developed δ18O chronologies of two dominant native trees, Dahurian larch (Larix gmelinii Rupr.) and Mongolian pine (Pinus sylvestris var. mongolica), from a permafrost region in the Great Hinggan Mountains of northeastern China. We found that the July-August VPD and relative humidity were the dominant factors that controlled tree ring δ18O in the study region, indicating strong regulation of stomatal conductance. Based on the larch and pine tree ring δ18O chronologies, we developed a reliable summer (July-August) VPD reconstruction since 1800. Warming growing season temperatures increase transpiration and enrich cellulose 18O, but precipitation seemed to be the most important influence on VPD changes in this cold region. Periods with stronger transpirational demand occurred around the 1850s, from 1914 to 1925, and from 2005 to 2010. However, we found no overall long-term increasing or decreasing trends for VPD since 1800, suggesting that despite the increasing temperatures and thawing permafrost throughout the region, forest transpirational demand has not increased significantly during the past two centuries. Under current climatic conditions, VPD did not limit growth of larch and pine, even during extremely drought years. Our findings will support more realistic evaluations and reliable predictions of the potential influences of ongoing climatic change on carbon and water cycles and on forest dynamics in permafrost regions.

  10. Stable isotope analyses of oxygen (18O:17O:16O) and chlorine (37Cl:35Cl) in perchlorate: reference materials, calibrations, methods, and interferences

    Science.gov (United States)

    Böhlke, John Karl; Mroczkowski, Stanley J.; Sturchio, Neil C.; Heraty, Linnea J.; Richman, Kent W.; Sullivan, Donald B.; Griffith, Kris N.; Gu, Baohua; Hatzinger, Paul B.

    2017-01-01

    RationalePerchlorate (ClO4−) is a common trace constituent of water, soils, and plants; it has both natural and synthetic sources and is subject to biodegradation. The stable isotope ratios of Cl and O provide three independent quantities for ClO4− source attribution and natural attenuation studies: δ37Cl, δ18O, and δ17O (or Δ17O or 17Δ) values. Documented reference materials, calibration schemes, methods, and interferences will improve the reliability of such studies.MethodsThree large batches of KClO4 with contrasting isotopic compositions were synthesized and analyzed against VSMOW-SLAP, atmospheric O2, and international nitrate and chloride reference materials. Three analytical methods were tested for O isotopes: conversion of ClO4− to CO for continuous-flow IRMS (CO-CFIRMS), decomposition to O2 for dual-inlet IRMS (O2-DIIRMS), and decomposition to O2 with molecular-sieve trap (O2-DIIRMS+T). For Cl isotopes, KCl produced by thermal decomposition of KClO4 was reprecipitated as AgCl and converted into CH3Cl for DIIRMS.ResultsKClO4 isotopic reference materials (USGS37, USGS38, USGS39) represent a wide range of Cl and O isotopic compositions, including non-mass-dependent O isotopic variation. Isotopic fractionation and exchange can affect O isotope analyses of ClO4− depending on the decomposition method. Routine analyses can be adjusted for such effects by normalization, using reference materials prepared and analyzed as samples. Analytical errors caused by SO42−, NO3−, ReO42−, and C-bearing contaminants include isotope mixing and fractionation effects on CO and O2, plus direct interference from CO2 in the mass spectrometer. The results highlight the importance of effective purification of ClO4− from environmental samples.ConclusionsKClO4 reference materials are available for testing methods and calibrating isotopic data for ClO4− and other substances with widely varying Cl or O isotopic compositions. Current ClO4−extraction, purification

  11. The evaluation and calculation of production cross sections of {sup 18}F, {sup 77}Br and {sup 186}Re medical radioisotopes from {sup 18}O, {sup 77}Se and {sup 186}W(p,n) reactions up to 80 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Youxiang, Zhuang [Chinese Nuclear Data Center, Beijing, BJ (China)

    1996-06-01

    The medical radioisotopes are used for diagnostic and therapeutic purposes, as well as metabolism and physiological function researches in modern medicine. The major applications are of functional imaging using PET agents for {sup 18}F, various therapeutic pharmaceuticals via auger electrons for {sup 77}Br, cancers diagnosis and therapy for {sup 186}Re. The evaluations of experimental data and theoretical calculations for {sup 18}O, {sup 77}Se, {sup 187}W(p,n) reactions up to 80 MeV are presented and analysed. The recommended values for {sup 18}O(p,n){sup 18}F, {sup 77}Se(p,n){sup 77}Br and {sup 186}W(p,n){sup 186}Re reaction cross sections are given. (6 figs.).

  12. Identification and correction of spectral contamination in 2H/1H and 18O/16O measured in leaf, stem, and soil water.

    Science.gov (United States)

    Schultz, Natalie M; Griffis, Timothy J; Lee, Xuhui; Baker, John M

    2011-11-15

    Plant water extracts typically contain organic materials that may cause spectral interference when using isotope ratio infrared spectroscopy (IRIS), resulting in errors in the measured isotope ratios. Manufacturers of IRIS instruments have developed post-processing software to identify the degree of contamination in water samples, and potentially correct the isotope ratios of water with known contaminants. Here, the correction method proposed by an IRIS manufacturer, Los Gatos Research, Inc., was employed and the results were compared with those obtained from isotope ratio mass spectrometry (IRMS). Deionized water was spiked with methanol and ethanol to create correction curves for δ(18)O and δ(2)H. The contamination effects of different sample types (leaf, stem, soil) and different species from agricultural fields, grasslands, and forests were compared. The average corrections in leaf samples ranged from 0.35 to 15.73‰ for δ(2)H and 0.28 to 9.27‰ for δ(18)O. The average corrections in stem samples ranged from 1.17 to 13.70‰ for δ(2)H and 0.47 to 7.97‰ for δ(18)O. There was no contamination observed in soil water. Cleaning plant samples with activated charcoal had minimal effects on the degree of spectral contamination, reducing the corrections, by on average, 0.44‰ for δ(2)H and 0.25‰ for δ(18)O. The correction method eliminated the discrepancies between IRMS and IRIS for δ(18)O, and greatly reduced the discrepancies for δ(2)H. The mean differences in isotope ratios between IRMS and the corrected IRIS method were 0.18‰ for δ(18)O, and -3.39‰ for δ(2)H. The inability to create an ethanol correction curve for δ(2)H probably caused the larger discrepancies. We conclude that ethanol and methanol are the primary compounds causing interference in IRIS analyzers, and that each individual analyzer will probably require customized correction curves. Copyright © 2011 John Wiley & Sons, Ltd.

  13. Stable isotope (δ18O and δ2H) data for precipitation, stream water, and groundwater in Puerto Rico

    Science.gov (United States)

    Scholl, Martha A.; Torres-Sanchez, Angel; Rosario-Torres, Manuel

    2014-01-01

    , hurricanes, and cold fronts, although frequent low-intensity orographic showers occur throughout the year in the mountains. The stable isotope signatures of rainfall (δ2H and δ18O) are broadly correlated with the weather type that produced the rainfall (Scholl and others, 2009; Scholl and Murphy, 2014).

  14. Laser spectrometry applied to the simultaneous determination of the δ2H, δ17O, and δ18O isotope abundances in water

    International Nuclear Information System (INIS)

    Kerstel, E.R.T.; Trigt, R. van; Dam, N.; Reuss, J.; Meijer, H.A.J.

    2001-01-01

    We demonstrate the first successful application of infrared laser spectrometry to the accurate, simultaneous determination of the relative 2 H/ 1 H, 17 O/ 16 O, and 18 O/ 16 O isotope abundance ratios in natural water. The method uses a narrow line width color center laser to record the direct absorption spectrum of low-pressure gas-phase water samples (presently 10 μl liquid) in the 3μm spectral region. The precision of the spectroscopic technique is shown to be 0.7 per mille for δ 2 H and 0.5 per mille for δ 17 O and δ 18 O, while the calibrated accuracy for natural waters amounts to about 3 per mille and 1 per mille, respectively. (author)

  15. Discovery of competing anaerobic and aerobic pathways in umpolung amide synthesis allows for site-selective amide 18O-labeling

    Science.gov (United States)

    Shackleford, Jessica P.; Shen, Bo; Johnston, Jeffrey N.

    2012-01-01

    The mechanism of umpolung amide synthesis was probed by interrogating potential sources for the oxygen of the product amide carbonyl that emanates from the α-bromo nitroalkane substrate. Using a series of 18O-labeled substrates and reagents, evidence is gathered to advance two pathways from the putative tetrahedral intermediate. Under anaerobic conditions, a nitro-nitrite isomerization delivers the amide oxygen from nitro oxygen. The same homolytic nitro-carbon fragmentation can be diverted by capture of the carbon radical intermediate with oxygen gas (O2) to deliver the amide oxygen from O2. This understanding was used to develop a straightforward protocol for the preparation of 18O-labeled amides in peptides by simply performing the umpolung amide synthesis reaction under an atmosphere of . PMID:22184227

  16. Mitigation of chromium poisoning of cathodes in solid oxide fuel cells employing CuMn1.8O4 spinel coating on metallic interconnect

    Science.gov (United States)

    Wang, Ruofan; Sun, Zhihao; Pal, Uday B.; Gopalan, Srikanth; Basu, Soumendra N.

    2018-02-01

    Chromium poisoning is one of the major reasons for cathode performance degradation in solid oxide fuel cells (SOFCs). To mitigate the effect of Cr-poisoning, a protective coating on the surface of interconnect for suppressing Cr vaporization is necessary. Among the various coating materials, Cu-Mn spinel coating is considered to be a potential candidate due to their good thermal compatibility, high stability and good electronic conductivity at high temperature. In this study, Crofer 22 H meshes with no protective coating, those with commercial CuMn2O4 spinel coating and the ones with lab-developed CuMn1.8O4 spinel coating were investigated. The lab-developed CuMn1.8O4 spinel coating were deposited on Crofer 22 H mesh by electrophoretic deposition and densified by a reduction and re-oxidation process. With these different Crofer 22 H meshes (bare, CuMn2O4-coated, and CuMn1.8O4-coated), anode-supported SOFCs with Sr-doped LaMnO3-based cathode were electrochemically tested at 800 °C for total durations of up to 288 h. Comparing the mitigating effects of the two types of Cu-Mn spinel coatings on Cr-poisoning, it was found that the performance of the denser lab-developed CuMn1.8O4 spinel coating was distinctly better, showing no degradation in the cell electrochemical performance and significantly less Cr deposition near the cathode/electrolyte interface after the test.

  17. Unveiling stomata 24/7: can we use carbonyl sulfide (COS) and oxygen isotopes (18O) to constrain estimates of nocturnal transpiration across different evolutionary plant forms?

    Science.gov (United States)

    Gimeno, Teresa E.; Ogee, Jerome; Bosc, Alexander; Genty, Bernard; Wohl, Steven; Wingate, Lisa

    2015-04-01

    Numerous studies have reported a continued flux of water through plants at night, suggesting that stomata are not fully closed. Growing evidence indicates that this nocturnal flux of transpiration might constitute an important fraction of total ecosystem water use in certain environments. However, because evaporative demand is usually low at night, nocturnal transpiration fluxes are generally an order of magnitude lower than rates measured during the day and perilously close to the measurement error of traditional gas-exchange porometers. Thus estimating rates of stomatal conductance in the dark (gnight) precisely poses a significant methodological challenge. As a result, we lack accurate field estimates of gnight and how it responds to different atmospheric drivers, indicating the need for a different measurement approach. In this presentation we propose a novel method to obtain detectable and robust estimates of gnight. We will demonstrate using mechanistic theory how independent tracers including the oxygen isotope composition of CO2 (δ18O) and carbonyl sulfide (COS) can be combined to obtain robust estimates of gnight. This is because COS and CO18O exchange within leaves are controlled by the light insensitive enzyme carbonic anhydrase. Thus, if plant stomata are open in the dark we will continue to observe COS and CO18O exchange. Using our theoretical model we will demonstrate that the exchange of these tracers can now be measured using advances in laser spectrometry techniques at a precision high enough to determine robust estimates of gnight. We will also present our novel experimental approach designed to measure simultaneously the exchange of CO18O and COS alongside the conventional technique that relies on measuring the total water flux from leaves in the dark. Using our theoretical approach we will additionally explore the feasibility of our proposed experimental design to detect variations in gnight during drought stress and across a variety of plant

  18. Synthesis, X-ray structure, and hydrolytic chemistry of the high potent antiviral polyniobotungstate A-[alpha]-[Si2Nb6W18O77]8–

    Science.gov (United States)

    Gyu-Shik Kim; Huadong Zeng; Jeffrey T. Rhule; Ira A. Weinstock; Craig L. Hill

    1999-01-01

    Potently antiviral polyniobotungstates have been structurally characterized; the dimer A-[alpha]-[Si2Nb6W18O77]8– cleaves cleanly to the monomer A-[alpha]-[SiNb3W9O40]7– within 1 min in aqueous solution buffered at physiological (neutral) pH establishing that the monomer and not the dimer is pharmacologically relevant.

  19. Study of C13/C12 and O18/O16 variations on environments of beach rocks formation in Itaparica island - Bahia

    International Nuclear Information System (INIS)

    Campos, H.S.

    1976-01-01

    Calcium carbonate-cemented beach sands or beach rocks have been observed to occur in the inter tidal zone of many tropical beaches. Near Salvador (Brazil) occurrences are found in several locations on the island of Itaparica. A study of the stable isotope composition (C 13 / C 12 and O 18 / O 16 ) of the cement and the local groundwater was carried out to determine the origin of the carbonate cement. (author)

  20. Study of the High Resolution Spectrum of the S18O16O Molecule in the Hot 2ν2 + ν3 - ν2 Band

    Science.gov (United States)

    Ziatkova, A. G.; Gromova, O. V.; Ulenikov, O. N.

    2018-05-01

    The hot 2ν2 + ν3 - ν2 hybrid band of the S18O16O molecule is assigned in the range 1800-1900 cm-1 for the first time. The spectrum is analyzed based on the method of combination differences. 56 energy levels (Jmax = 15, {K}a^{max}=12 ) are determined based on the experimental data obtained. Rotational parameters of the (021) vibrational state are determined.

  1. Comparison of 18O Isotopic Exchange After and During the Interaction of N2O, NO and NO2 with Fe Ions in Ferrierites

    Czech Academy of Sciences Publication Activity Database

    Nováková, Jana; Sobalík, Zdeněk

    2003-01-01

    Roč. 89, 3/4 (2003), s. 243-247 ISSN 1011-372X R&D Projects: GA AV ČR IBS4040016; GA MŠk OC D15.20 Institutional research plan: CEZ:AV0Z4040901 Keywords : Fe-ferrierite * N oxides * 18O2 exchange Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.581, year: 2003

  2. On the calibration of continuous, high-precision delta18O and delta2H measurements using an off-axis integrated cavity output spectrometer.

    Science.gov (United States)

    Wang, Lixin; Caylor, Kelly K; Dragoni, Danilo

    2009-02-01

    The (18)O and (2)H of water vapor serve as powerful tracers of hydrological processes. The typical method for determining water vapor delta(18)O and delta(2)H involves cryogenic trapping and isotope ratio mass spectrometry. Even with recent technical advances, these methods cannot resolve vapor composition at high temporal resolutions. In recent years, a few groups have developed continuous laser absorption spectroscopy (LAS) approaches for measuring delta(18)O and delta(2)H which achieve accuracy levels similar to those of lab-based mass spectrometry methods. Unfortunately, most LAS systems need cryogenic cooling and constant calibration to a reference gas, and have substantial power requirements, making them unsuitable for long-term field deployment at remote field sites. A new method called Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS) has been developed which requires extremely low-energy consumption and neither reference gas nor cryogenic cooling. In this report, we develop a relatively simple pumping system coupled to a dew point generator to calibrate an ICOS-based instrument (Los Gatos Research Water Vapor Isotope Analyzer (WVIA) DLT-100) under various pressures using liquid water with known isotopic signatures. Results show that the WVIA can be successfully calibrated using this customized system for different pressure settings, which ensure that this instrument can be combined with other gas-sampling systems. The precisions of this instrument and the associated calibration method can reach approximately 0.08 per thousand for delta(18)O and approximately 0.4 per thousand for delta(2)H. Compared with conventional mass spectrometry and other LAS-based methods, the OA-ICOS technique provides a promising alternative tool for continuous water vapor isotopic measurements in field deployments. Copyright 2009 John Wiley & Sons, Ltd.

  3. Microwave-enhanced electrochemical cycling performance of the LiNi0.2Mn1.8O4 spinel cathode material at elevated temperature

    CSIR Research Space (South Africa)

    Raju, Kumar

    2016-04-01

    Full Text Available microwave-assisted solid-state reaction has been used to dope LMO with a very low amount of nickel (i.e., LiNi(sub0.2)Mn(sub1.8)O(sub4), herein abbreviated as LMNO) for lithium-ion batteries from Mn(sub3)O(sub4) which is prepared from electrolytic manganese...

  4. Consistently dated records from the Greenland GRIP, GISP2 and NGRIP ice cores for the past 104ka reveal regional millennial-scale δ18O gradients with possible Heinrich event imprint

    DEFF Research Database (Denmark)

    Seierstad, Inger K.; Abbott, Peter M.; Bigler, Matthias

    2014-01-01

    are generally very similar and display synchronous behaviour at climate transitions. The δ18O differences between Summit and NGRIP, however, changed slowly over the Last Glacial-Interglacial cycle and also underwent abrupt millennial-to-centennial-scale variations. We suggest that this observed latitudinal δ18O...

  5. δ18O water isotope in the iLOVECLIM model (version 1.0 – Part 1: Implementation and verification

    Directory of Open Access Journals (Sweden)

    D. M. Roche

    2013-09-01

    Full Text Available A new 18O stable water isotope scheme is developed for three components of the iLOVECLIM coupled climate model: atmospheric, oceanic and land surface. The equations required to reproduce the fractionation of stable water isotopes in the simplified atmospheric model ECBilt are developed consistently with the moisture scheme. Simplifications in the processes are made to account for the simplified vertical structure including only one moist layer. Implementation of these equations together with a passive tracer scheme for the ocean and a equilibrium fractionation scheme for the land surface leads to the closure of the (isotopic- water budget in our climate system. Following the implementation, verification of the existence of usual δ18O to climatic relationships are performed for the Rayleigh distillation, the Dansgaard relationship and the δ18O –salinity relationship. Advantages and caveats of the approach taken are outlined. The isotopic fields simulated are shown to reproduce most expected oxygen-18–climate relationships with the notable exception of the isotopic composition in Antarctica.

  6. Characterization of biodegradation intermediates of nonionic surfactants by MALDI-MS. 2. Oxidative biodegradation profiles of uniform octylphenol polyethoxylate in 18O-labeled water.

    Science.gov (United States)

    Sato, Hiroaki; Shibata, Atsushi; Wang, Yang; Yoshikawa, Hiromichi; Tamura, Hiroto

    2003-01-01

    This paper reports the characterization of the biodegradation intermediates of octylphenol octaethoxylate (OP(8)EO) by means of matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The biodegradation test study was carried out in a pure culture (Pseudomonas putida S-5) under aerobic conditions using OP(8)EO as the sole carbon source and (18)O-labeled water as an incubation medium. In the MALDI-MS spectra of biodegraded samples, a series of OP(n)EO molecules with n = 2-8 EO units and their corresponding carboxylic acid products (OP(n)EC) were observed. The use of purified OP(8)EO enabled one to distinguish the shortened OPEO molecules as biodegradation intermediates. Furthermore, the formation of OP(8)EC (the oxidized product of OP(8)EO) supported the notion that terminal oxidation is a step in the biodegradation process. When biodegradation study was carried out in (18)O-labeled water, incorporation of (18)O atoms into the carboxyl group was observed for OPEC, while no incorporation was observed for the shortened OPEO products. These results could provide some rationale to the biodegradation mechanism of alkylphenol polyethoxylates.

  7. Reversible formation of intermediates during H3O+-catalyzed hydrolysis of amides. Observation of substantial 18O exchange accompanying the hydrolysis of acetanilide and N-cyclohexylacetamide

    International Nuclear Information System (INIS)

    Slebocka-Tilk, H.; Brown, R.S.; Olekszyk, J.

    1987-01-01

    Careful mass spectrometric analysis of the 18 O content of ∼ 50% enriched acetanilide (2) and N-cyclohexylacetamide (3) recovered from acidic media during the course of hydrolysis reveals that both species suffer 18 O loss. The percent of 18 O exchange per t/sub 1/2/ of hydrolysis increases as [H 3 O + ] decreases. For 2 at 72 0 C the amount of exchange increases from 0.5 +/- 0.5% (per t/sub 1/2/) in 1 M HCl to 9.4 +/- 0.5% in glycine buffer, [H 3 O + ] = 0.003 M. For 3 at 100 0 C the exchange is 1.05 +/- 0.3% (per t/sub 1/2/) at 1 M HCl and 9.0 +/- 0.4% in 0.01 M HCl. When these data are used to compute k/sub ex/ (the exchange rate constant), it shows a first-order dependence on [H 3 O + ] followed by a plateau at high [H 3 O + ] for both 2 and 3

  8. UV-laser-based microscopic dissection of tree rings - a novel sampling tool for δ(13) C and δ(18) O studies.

    Science.gov (United States)

    Schollaen, Karina; Heinrich, Ingo; Helle, Gerhard

    2014-02-01

    UV-laser-based microscopic systems were utilized to dissect and sample organic tissue for stable isotope measurements from thin wood cross-sections. We tested UV-laser-based microscopic tissue dissection in practice for high-resolution isotopic analyses (δ(13) C/δ(18) O) on thin cross-sections from different tree species. The method allows serial isolation of tissue of any shape and from millimetre down to micrometre scales. On-screen pre-defined areas of interest were automatically dissected and collected for mass spectrometric analysis. Three examples of high-resolution isotopic analyses revealed that: in comparison to δ(13) C of xylem cells, woody ray parenchyma of deciduous trees have the same year-to-year variability, but reveal offsets that are opposite in sign depending on whether wholewood or cellulose is considered; high-resolution tree-ring δ(18) O profiles of Indonesian teak reflect monsoonal rainfall patterns and are sensitive to rainfall extremes caused by ENSO; and seasonal moisture signals in intra-tree-ring δ(18) O of white pine are weighted by nonlinear intra-annual growth dynamics. The applications demonstrate that the use of UV-laser-based microscopic dissection allows for sampling plant tissue at ultrahigh resolution and unprecedented precision. This new technique facilitates sampling for stable isotope analysis of anatomical plant traits like combined tree eco-physiological, wood anatomical and dendroclimatological studies. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  9. Isotope tracing ({sup 29}Si and {sup 18}O) of the alteration mechanisms of the French glass 'SON68' used for the storage of nuclear waste; Tracage isotopique ({sup 29}Si and {sup 18}O) des mecanismes de l'alteration du verre de confinement des dechets nucleaires: 'SON68'

    Energy Technology Data Exchange (ETDEWEB)

    Valle, N

    2001-07-01

    This study aims to enhance our understanding of the mechanisms of aqueous corrosion of the glasses used for the storage of nuclear waste. Glass samples 'SON68', doped with a different rare earth element (La, Ce or Nd), were altered simultaneously with water enriched in {sup 29}Si and {sup 18}O, throughout a period of 20 months. The aim of such isotope tracing was (i) to follow the 'real' exchanges between glass and solution and (ii) to understand the reactions involving Si-O bonds in the leached layer during alteration. Leachates were analyzed by ICP-MS and -AES, and elemental and isotopic variations in the altered glass layer were measured by ion-probe, using a depth profiling technique. Elemental analyses enabled the distribution of the elements in the two layers of altered glass (phyllosilicates and gel) to be established, and the results reveal a selective partitioning of elements between the two layers. Isotopic analyses of altered layers and leachates allowed phyllosilicates to be distinguished from gel, and suggest two different mechanisms of formation. Whilst phyllosilicates grow on the surface of the glass by a mechanism of precipitation, gel is formed by a succession of hydrolysis / condensation reactions taking place mainly at the gel / pristine glass interface. This gel is formed by the in situ rearrangement of hydrated species, without reaching equilibrium with the solution. Moreover, an experimental technique has been developed enabling one to trace the transport of silicon from the solution into the altered glasses, under an isotopic gradient. Diffusion profiles, obtained by ion-probe, have been modeled and have allowed the determination of the apparent silicon diffusion coefficient (DSi) in gels. Therefore, our experiments have permitted the quantification of the influence of both the alteration conditions (dynamic or static tests) and the solution composition on the value of DSi. (author)

  10. A Modern Sr/Ca-δ18O-Sea Surface Temperature Calibration for Isopora Corals in the Great Barrier Reef

    Science.gov (United States)

    Brenner, L. D.; Linsley, B. K.; Potts, D. C.

    2014-12-01

    Most coral-based paleoceanographic studies have used massive colonies of Porites or Faviidae, due to their long, continuously accreted skeletal records and sub-annual resolution, but other sub-massive corals provide an untapped resource. The genus Isopora is a dominant reef builder in some high-energy environments in the tropical western Pacific, and was a major component of cores recovered on IODP Leg 325 off the Great Barrier Reef (GBR). Despite its abundance, Isopora remains largely unexplored and hence underutilized in paleoceanographic studies. We present a modern Sr/Ca-δ18O-Sea Surface Temperature (SST) calibration of modern Isopora corals (n=3) collected from inner and outer reef locations ranging from 1-13m depth by Heron Island in the southern GBR in 2012. Pairing the Isopora Sr/Ca record with monthly SST yielded an average relationship of SST=-11.48×(Sr/Ca)+131.1 (r2 = 0.42-0.78). The Sr/Ca sensitivity of -0.087 mmol/mol/°C is similar to the sensitivity for Porites that was corrected for tissue layer smoothing effects determined by Gagan et al. (2012). The similarity between our Sr/Ca-SST sensitivity and the corrected sensitivity for Porites suggests tissue layer effects are minimal in Isopora. The mean annual SST amplitude recorded by the corals from 2008-2011 (full annual cycles) was 5.3°C and the average δ18O annual cycle of 1.1‰ approximates that expected if salinity had little effect on coral δ18O, assuming a previously established conversion of -0.23‰ (δ18O)/°C for biogenic aragonite. The average annual salinity amplitude of 0.3 in gridded data from around Heron Island supports our conclusion that δ18O variability is forced almost completely by SST. This modern Sr/Ca-SST calibration will expand the paleoceanographic utility of Isopora and, by assisting interpretation of Sr/Ca data from fossil corals collected during IODP 325, will better constrain the timing and magnitude of sea level changes and surface conditions since the Last

  11. Imprints of Climate Signals in a 204 Year δ18O Tree-Ring Record of Nothofagus pumilio From Perito Moreno Glacier, Southern Patagonia (50°S

    Directory of Open Access Journals (Sweden)

    Jussi Grießinger

    2018-04-01

    Full Text Available A 204 year-long record of δ18O in tree-ring cellulose of southern beech (Nothofagus pumilio from a site near Perito Moreno Glacier (50°S in Southern Patagonia was established to assess its potential for a climate reconstruction. The annually resolved oxygen isotope chronology is built out of seven individual tree-ring δ18O series with a significant mean inter-series correlation (r = 0.61 and is the first of its kind located in Southern America south of 50°S. Over a common period from 1960 to 2013 of available stationary and high-resolution gridded CRU TS v. 4.01 data, the δ18O chronology exhibits a strong sensitivity toward hydroclimatic as well as temperature parameters as revealed by correlation analyses. Among these, positive correlations with maximum temperature in the first part of the summer season (CRU rONDJ = 0.51, p < 0.01 and negative correlations with precipitation in the latter half of the vegetation period (CRU rONDJ = −0.54, p < 0.01 show the highest sensitivities. A strong supra-regional influence of the Southern Annular Mode (SAM is clearly recorded in this chronology as indicated by significant positive correlations during the vegetation period (rONDJ = 0.62, p < 0.01. This indicates that the presented δ18O-chronology shows great promise to reconstruct the influence and variability of the SAM within the last two centuries in southern South America. The modulation of positive and negative anomalies within this series can be interlinked to changes in moisture source origin as revealed by backward trajectory modeling. Additionally, these anomalies can be directly associated to positive or negative phases of the Antarctic Oscillation Index (AAOI and therefore the strength of the Westerlies. Aligned by the analysis on the influence of different main weather types on the δ18O chronology it is shown that such time-series hold the potential to additionally capture their respective influence and change during the last centuries.

  12. A comparative proteomics method for multiple samples based on a 18O-reference strategy and a quantitation and identification-decoupled strategy.

    Science.gov (United States)

    Wang, Hongbin; Zhang, Yongqian; Gui, Shuqi; Zhang, Yong; Lu, Fuping; Deng, Yulin

    2017-08-15

    Comparisons across large numbers of samples are frequently necessary in quantitative proteomics. Many quantitative methods used in proteomics are based on stable isotope labeling, but most of these are only useful for comparing two samples. For up to eight samples, the iTRAQ labeling technique can be used. For greater numbers of samples, the label-free method has been used, but this method was criticized for low reproducibility and accuracy. An ingenious strategy has been introduced, comparing each sample against a 18 O-labeled reference sample that was created by pooling equal amounts of all samples. However, it is necessary to use proportion-known protein mixtures to investigate and evaluate this new strategy. Another problem for comparative proteomics of multiple samples is the poor coincidence and reproducibility in protein identification results across samples. In present study, a method combining 18 O-reference strategy and a quantitation and identification-decoupled strategy was investigated with proportion-known protein mixtures. The results obviously demonstrated that the 18 O-reference strategy had greater accuracy and reliability than other previously used comparison methods based on transferring comparison or label-free strategies. By the decoupling strategy, the quantification data acquired by LC-MS and the identification data acquired by LC-MS/MS are matched and correlated to identify differential expressed proteins, according to retention time and accurate mass. This strategy made protein identification possible for all samples using a single pooled sample, and therefore gave a good reproducibility in protein identification across multiple samples, and allowed for optimizing peptide identification separately so as to identify more proteins. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Regional influence of decadal to multidecadal Atlantic Oscillations during the last two millennia in Morocco, inferred from two high resolution δ18O speleothem records

    Science.gov (United States)

    Ait Brahim, Yassine; Sifeddine, Abdelfettah; Khodri, Myriam; Bouchaou, Lhoussaine; Cruz, Francisco W.; Pérez-Zanón, Núria; Wassenburg, Jasper A.; Cheng, Hai

    2017-04-01

    Climate projections predict substantial increase of extreme heats and drought occurrences during the coming decades in Morocco. It is however not clear what can be attributed to natural climate variability and to anthropogenic forcing, as hydroclimate variations observed in areas such as Morocco are highly influenced by the Atlantic climate modes. Since observational data sets are too short to resolve properly natural modes of variability acting on decadal to multidecadal timescales, high resolution paleoclimate reconstructions are the only alternative to reconstruct climate variability in the remote past. Herein, we present two high resolution and well dated speleothems oxygen isotope (δ18O) records sampled from Chaara and Ifoulki caves (located in Northeastern and Southwestern Morocco respectively) to investigate hydroclimate variations during the last 2000 years. Our results are supported by a monitoring network of δ18O in precipitation from 17 stations in Morocco. The new paleoclimate records are discussed in the light of existing continental and marine paleoclimate proxies in Morocco to identify significant correlations at various lead times with the main reconstructed oceanic and atmospheric variability modes and possible climate teleconnections that have potentially influenced the climate during the last two millennia in Morocco. The results reveal substantial decadal to multidecadal swings between dry and humid periods, consistent with regional paleorecords. Evidence of dry conditions exist during the Medieval Climate Anomaly (MCA) period and the Climate Warm Period (CWP) and humid conditions during the Little Ice Age (LIA) period. Statistical analyses suggest that the climate of southwestern Morocco remained under the combined influence of both the Atlantic Multidecadal Oscillation (AMO) and the North Atlantic Oscillation (NAO) over the last two millennia. Interestingly, the generally warmer MCA and colder LIA at longer multidecadal timescales probably

  14. Synthesis of LiMn2O4 and LiCr0.2Mn1.8O4 powders by modified Pechini process

    Directory of Open Access Journals (Sweden)

    Alexandre Urbano

    2009-03-01

    Full Text Available LiMn2O4 and LiCr0.2Mn1.8O4 powders were synthesized by Pechini process, modified in order to reduce the number of steps and to work at temperatures below or equal to 400oC. Both phases crystallize in the same spinel structure with lattice constants of 8.21 and 8.22 Å respectively. Although the annealing temperature was low, the cristallinity is good and no residual amounts of organic material were detected.

  15. Extracting the cross section angular distributions for 15C high-energy resonance excited via the (18O,16O two-neutron transfer reaction

    Directory of Open Access Journals (Sweden)

    Carbone D.

    2016-01-01

    Full Text Available The 13C(18O,16O15C reaction has been studied at 84 MeV incident energy. The ejectiles have been momentum analized by the MAGNEX spectrometer and 15C excitation energy spectra have been obtained up to about 20 MeV. In the region above the two-neutron separation energy, a bump has been observed at 13.7 MeV. The extracted cross section angular distribution for this structure, obtained by using different models for background, displays a clear oscillating pattern, typical of resonant state of the residual nucleus.

  16. Multipolarity analysis for {sup 14}C high-energy resonance populated by ({sup 18}O,{sup 16}O) two-neutron transfer reaction

    Energy Technology Data Exchange (ETDEWEB)

    Carbone, D., E-mail: carboned@lns.infn.it; Cavallaro, M.; Bondì, M.; Agodi, C.; Cunsolo, A. [INFN-Laboratori Nazionali del Sud, Catania (Italy); Cappuzzello, F. [INFN-Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Fisica e Astronomia, Università di Catania, Catania (Italy); Azaiez, F.; Franchoo, S.; Khan, E. [Institut de Physique Nucleaire, Universitè Paris-Sud, Orsay (France); Bonaccorso, A. [INFN-Sezione di Pisa, Pisa (Italy); Fortunato, L. [Dipartimento di Fisica e Astronomia, Università di Padova, Padova (Italy); INFN-Sezione di Padova, Padova (Italy); Foti, A. [Dipartimento di Fisica e Astronomia, Università di Catania, Catania (Italy); INFN-Sezione di Catania, Catania (Italy); Linares, R.; Lubian, J. [Instituto de Fisica, Universidade Federal Fluminense, Niteroi (Brazil); Scarpaci, J. A. [Centre de Sciences Nucleaires et de Sciences de Matieres, Universitè Paris-Sud, Orsay (France); Vitturi, A. [INFN-Sezione di Padova, Padova (Italy); INFN-Sezione di Catania, Catania (Italy)

    2015-10-15

    The {sup 12}C({sup 18}O,{sup 16}O){sup 14}C reaction at 84 MeV incident energy has been explored up to high excitation energy of the residual nucleus thanks to the use of the MAGNEX spectrometer to detect the ejectiles. In the region above the two-neutron separation energy, a resonance has been observed at 16.9 MeV. A multipolarity analysis of the cross section angular distribution indicates an L = 0 character for such a transition.

  17. Tracing groundwater recharge sources in the northwestern Indian alluvial aquifer using water isotopes (δ18O, δ2H and 3H)

    Science.gov (United States)

    Joshi, Suneel Kumar; Rai, Shive Prakash; Sinha, Rajiv; Gupta, Sanjeev; Densmore, Alexander Logan; Rawat, Yadhvir Singh; Shekhar, Shashank

    2018-04-01

    Rapid groundwater depletion from the northwestern Indian aquifer system in the western Indo-Gangetic basin has raised serious concerns over the sustainability of groundwater and the livelihoods that depend on it. Sustainable management of this aquifer system requires that we understand the sources and rates of groundwater recharge, however, both these parameters are poorly constrained in this region. Here we analyse the isotopic (δ18O, δ2H and tritium) compositions of groundwater, precipitation, river and canal water to identify the recharge sources, zones of recharge, and groundwater flow in the Ghaggar River basin, which lies between the Himalayan-fed Yamuna and Sutlej River systems in northwestern India. Our results reveal that local precipitation is the main source of groundwater recharge. However, depleted δ18O and δ2H signatures at some sites indicate recharge from canal seepage and irrigation return flow. The spatial variability of δ18O, δ2H, d-excess, and tritium reflects limited lateral connectivity due to the heterogeneous and anisotropic nature of the aquifer system in the study area. The variation of tritium concentration with depth suggests that groundwater above c. 80 mbgl is generally modern water. In contrast, water from below c. 80 mbgl is a mixture of modern and old waters, and indicates longer residence time in comparison to groundwater above c. 80 mbgl. Isotopic signatures of δ18O, δ2H and tritium suggest significant vertical recharge down to a depth of 320 mbgl. The spatial and vertical variations of isotopic signature of groundwater reveal two distinct flow patterns in the aquifer system: (i) local flow (above c. 80 mbgl) throughout the study area, and (ii) intermediate and regional flow (below c. 80 mbgl), where water recharges aquifers through large-scale lateral flow as well as vertical infiltration. The understanding of spatial and vertical recharge processes of groundwater in the study area provides important base-line knowledge

  18. 2H, 3H and 18O Tracers used for a preliminary study of groundwaters vulnerability to contaminants in the South-West of Madagascar

    International Nuclear Information System (INIS)

    Rajaobelison, J.; Ramaroson, V.; Randrianasolo, A.; Randrianarisoa, H.; Mamifarananahary, E.; Ranaivoarisoa, A.

    2004-01-01

    Fresh water access is one of the main issues in the South-West of Madagascar. Most people in this area draw water from surface water which is usually of bad quality and source of stomach diseases. The only reliable water resource is groundwater. However, the latter is more or less vulnerable to geogenic and anthropogenic contaminants. Use of 2 H, 3 H and 18 O environmental tracers has contributed to localize and estimate the active and potential focuses of contamination in shallower and deeper aquifers, within the frame of a preliminary study of ground waters vulnerability to contaminants.

  19. Indirect Measurement of 15N(p,α)12C and 18O(p,α)15N. Applications to the AGB Star Nucleosynthesis

    International Nuclear Information System (INIS)

    La Cognata, M.; Spitaleri, C.; Cherubini, S.; Crucilla, V.; Gulino, M.; Lamia, L.; Pizzone, R. G.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Tumino, A.; Tribble, R.; Al-Abdullah, T.; Banu, A.; Fu, C.; Goldberg, V.; Mukhamedzhanov, A.; Tabacaru, G.; Trache, L.

    2008-01-01

    The Trojan Horse Method has been recently applied to the study of reactions involved in fluorine nucleosynthesis inside AGB stars. Fluorine abundance is important since it allows to constrain mixing models from the comparison of the observed fluorine abundances with the ones predicted by models. Anyway direct measurements of the cross section do not extend down to the Gamow peak, which is the astrophysically relevant energy region. In particular the study focuses on the 15 N(p,α) 12 C and the 18 O(p,α) 15 N reactions which can influence fluorine yield as they are part of 19 F production/destruction network

  20. Circulation path of thermal waters within the Laga foredeep basin inferred from chemical and isotopic (δ18O, δD, 3H, 87Sr/86Sr) data

    International Nuclear Information System (INIS)

    Fusari, Alessandro; Carroll, Michael R.; Ferraro, Stefano; Giovannetti, Rita; Giudetti, Geoffrey; Invernizzi, Chiara; Mussi, Mario; Pennisi, Maddalena

    2017-01-01

    The geochemistry of thermal spring waters in the Acquasanta Terme area, located on the Adriatic side of central Italy, has been investigated in order to characterize the geothermal feeding system. The springs discharge more than 100 L/s at temperature ranging between 20 and 30 °C. They occur in a tectonic window of Mesozoic limestones in the central sector of the Acquasanta anticline within the Laga foredeep Basin. Chemical and isotopic compositions of thermal and cold fluids were investigated, most of them monitored for one year, in order to understand the thermal fluid circulation paths. The chemistry of the major elements defines the existence of Na–Cl and Ca–Cl–SO 4 2- hot discharging waters and permits the characterization of the thermal end-member hosted in carbonate-dominated reservoir (Burano Anhydrites Fm–Calcare Massiccio Fm). This deep fluid is well represented by the sample T1 and shows high temperature and electrical conductivity (EC), very stable over time, and not affected by mixing phenomena. This is also confirmed by tritium results (0 T.U.). Close to the surface at different depth, such water undergoes mixing or dilution processes with HCO 3 − rich freshwaters, driven by the complex structural setting of the area and by diffuse karst caves. This is identified as the main reason for observed compositional variations of sampled springs, and three areas affected by different mixing phenomena have been defined at the surface. The concentrations of SO 4 2− and H 2 S suggest redox processes affecting sulfur after interaction with evaporitic formations, identified with the Burano Anhydrites, at the base of the Umbria–Marche sedimentary sequence (∼3500-m-deep). Contribution from this reservoir is also supported by characteristic Sr isotope signature. δ 18 O and δD values indicate a meteoric origin of the thermal waters and allow estimation of an average infiltration altitude ranging between 1500 and 1700 m a.s.l. This datum

  1. Human impacts on groundwater flow and contamination deduced by multiple isotopes in Seoul City, South Korea

    Energy Technology Data Exchange (ETDEWEB)

    Hosono, Takahiro, E-mail: hosono@chikyu.ac.jp [Research Institute for Humanity and Nature, 457-4 Motoyama Kamigamo, Kita-ku, Kyoto 603-8047 (Japan); Ikawa, Reo, E-mail: r_ikawa@es.sci.kumamoto-u.ac.jp [Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Shimada, Jun, E-mail: jshimada@sci.kumamoto-u.ac.jp [Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Nakano, Takanori, E-mail: nakanot@chikyu.ac.jp [Research Institute for Humanity and Nature, 457-4 Motoyama Kamigamo, Kita-ku, Kyoto 603-8047 (Japan); Saito, Mitsuyo, E-mail: misaito@hiroshima-u.ac.jp [Graduate School of Biosphere Science, Hiroshima University, 1-7-1, Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8521 (Japan); Onodera, Shin-ichi, E-mail: sonodera@hiroshima-u.ac.jp [Graduate School of Integrated Arts and Sciences, Hiroshima University, 1-7-1, Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8521 (Japan); Lee, Kang-Kun, E-mail: kklee@snu.ac.kr [School of Earth and Environmental Science, Seoul National University, San 56-1, Shinrim-dong, Kwanak-gu, Seoul 151-747 (Korea, Republic of); Taniguchi, Makoto, E-mail: makoto@chikyu.ac.jp [Research Institute for Humanity and Nature, 457-4 Motoyama Kamigamo, Kita-ku, Kyoto 603-8047 (Japan)

    2009-04-15

    The influence of human activities on the flow system and contamination of groundwater were investigated in Seoul City, South Korea, one of the largest Asian cities, using a combination of isotopes ({delta}D, T, {delta}{sup 15}N, {delta}{sup 18}O, {delta}{sup 34}S, and {sup 87}Sr/{sup 86}Sr). Eighteen representative groundwater and river water samples, which were collected over a wide area of the city, were compared with previously reported data. The distribution of stable isotopes ({delta}D and {delta}{sup 18}O) with groundwater potential data shows that recharged groundwater from either the surrounding mountainous area as well as the Han River and other surface streams discharged towards the northern-central part of the city, where a subway tunnel pumping station is located. It is suggested from T values (3.3 to 5.8 T.U.) that groundwater was recharged in the last 30 to 40 years. The {delta}{sup 34}S and {delta}{sup 15}N of SO{sub 4}{sup 2-} and NO{sub 3}{sup -} data were efficiently used as indicators of contamination by human activities. These isotopes clarified that the contribution of anthropogenic contaminants i.e., industrial and household effluents, waste landfills, and fertilizers, are responsible for the enrichment by SO{sub 4}{sup 2-} (> 30 ppm as SO{sub 4}{sup 2-}) and NO{sub 3}{sup -} (> 20 ppm as NO{sub 3}{sup -}) of groundwater. The {sup 87}Sr/{sup 86}Sr values of groundwater vary (0.71326 to 0.75058) in accordance with the host rocks of different origins. Mineral elements such as Ca are also suggested to be derived naturally from rocks. The groundwater under Seoul City is greatly affected by transportation of pollutants along the groundwater flow controlled by subway tunnel pumping, contributing to the degradation of water quality in urbanized areas.

  2. Resonance strengths in the {sup 17,18}O(p, α){sup 14,15}N reactions and background suppression underground. Commissioning of a new setup for charged-particle detection at LUNA

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, C.G.; Scott, D.A.; Aliotta, M.; Davinson, T.; Griffin, C.J. [University of Edinburgh, SUPA, School of Physics and Astronomy, Edinburgh (United Kingdom); Formicola, A.; Best, A.; Junker, M. [Laboratori Nazionali del Gran Sasso, INFN, Assergi (Italy); Anders, M.; Bemmerer, D.; Szuecs, T. [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany); Broggini, C.; Menegazzo, R. [INFN, Padova (Italy); Caciolli, A.; Depalo, R. [INFN, Padova (Italy); Universita di Padova, Dipartimento di Fisica e Astronomia, Padova (Italy); Cavanna, F.; Corvisiero, P.; Prati, P. [INFN, Genova (Italy); Dipartimento di Fisica, Universita di Genova, Genova (Italy); Di Leva, A.; Imbriani, G. [Universita di Napoli ' ' Federico II' ' , Dipartimento di Scienze Fisiche, Napoli (Italy); Elekes, Z.; Fueloep, Zs.; Gyuerky, Gy.; Somorjai, E. [MTA Atomki, Institute of Nuclear Research, Debrecen (Hungary); Gervino, G. [Universita degli Studi di Torino, Dipartimento di Fisica Sperimentale, Torino (Italy); Guglielmetti, A.; Trezzi, D. [Universita degli Studi di Milano (Italy); INFN, Milano (Italy); Gustavino, C. [INFN, Roma (Italy); Napolitani, E. [Universita di Padova, Dipartimento di Fisica e Astronomia, Padova (Italy); Straniero, O. [Laboratori Nazionali del Gran Sasso, INFN, Assergi (Italy); Osservatorio Astronomico di Collurania, Teramo (Italy); Strieder, F. [South Dakota School of Mines and Technology, Rapid City, SD (United States); Collaboration: LUNA Collaboration

    2015-08-15

    We report on measurements of resonance strengths and energies for the E{sub p} = 151 and 193 keV resonances in the {sup 18}O(p, α){sup 15}N and {sup 17}O(p, α){sup 14}N reactions, respectively, obtained during commissioning of a new setup for alpha-particle detection studies at the LUNA underground laboratory. Our values, ωγ(151) = 164.2 ± 0.9{sub stat-11.7}{sup +12.1}{sub syst} meV and ωγ (193) = 1.68 ± 0.03{sub stat} ± 0.12{sub syst} meV, are in excellent agreement with those reported in the literature. New values of resonance energies are E{sub p} = 151.2 ± 0.3 keV and E{sub p} = 194.8 ± 0.3 keV, respectively, this latter with the highest precision to date. Comparative background measurements in silicon detectors overground and underground were also carried out, yielding up to a factor of 15 in background suppression at LUNA at energies around 200 keV. This clearly demonstrates the usefulness of underground measurements in charged-particles experiments, especially at low detection energies. (orig.)

  3. Regional drought shifts (1710-2010) in East Central Asia and linkages with atmospheric circulation recorded in tree-ring δ18O

    Science.gov (United States)

    Xu, Guobao; Liu, Xiaohong; Trouet, Valerie; Treydte, Kerstin; Wu, Guoju; Chen, Tuo; Sun, Weizhen; An, Wenling; Wang, Wenzhi; Zeng, Xiaomin; Qin, Dahe

    2018-04-01

    Drought occurrence and duration in central Asia are of important socioeconomic, ecological, and geophysical significance and have received increasing research attention in recent years. Understanding long-term drought trends and their driving forces require reliable records of past drought variability with broad spatial representativeness. Here, we compiled four tree-ring δ18O records from eastern central Asia (ECA) and composited them into a drought-sensitive proxy to explore regional ECA moisture variations over the past 301 years (1710-2010 CE). A robust regional standardized precipitation-evapotranspiration index (SPEI) reconstruction was established based on the tree-ring cellulose δ18O fractionation mechanism and statistically significant proxy-climate relationships. We identified prominent droughts in 1710-1770, 1810-1830, and the beginning of the twenty-first century, and a regime shift to a persistently wet period from the 1880s to 2000. Our reconstruction reveals the impact of drought and pluvial patterns on the decline of Zhungar Empire, and on historical agricultural and socio-economical activities, including increased migration into ECA during the 1770-1800 pluvial. Our findings also suggest that wet conditions in the twentieth century in ECA were related to a strengthening of the westerly circulation and thus shed light on large-scale atmospheric circulation dynamics in central Asia.

  4. Understanding the two neutron transfer reaction mechanism in {sup 206}Pb({sup 18}O,{sup 16}O){sup 208}Pb

    Energy Technology Data Exchange (ETDEWEB)

    Parmar, A.; Sonika [Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai - 400 085 (India); Roy, B.J., E-mail: bjroy@barc.gov.in [Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai - 400 085 (India); Jha, V.; Pal, U.K. [Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai - 400 085 (India); Sinha, T. [High Energy Nuclear and Particle Physics Division, Saha Institute of Nuclear Physics, Kolkata - 700 064 (India); Pandit, S.K.; Parkar, V.V.; Ramachandran, K.; Mahata, K.; Santra, S.; Mohanty, A.K. [Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai - 400 085 (India)

    2015-08-15

    The absolute cross sections for elastic scattering and two-neutron transfer reaction for {sup 18}O + {sup 206}Pb system have been measured at an incident energy near the Coulomb barrier. Detailed coupled reaction channel calculations have been carried out for description of the measured angular distributions for the elastic scattering and transfer reactions simultaneously. The two-neutron transfer reaction {sup 206}Pb({sup 18}O, {sup 16}O){sup 208}Pb in the g.s. → g.s. transition is analyzed in (i) extreme cluster model assuming a di-neutron transfer, (ii) two-step successive transfer, and (iii) microscopic approach (independent coordinate scheme) of simultaneous transfer of two neutrons. The relative importance of one step simultaneous transfer versus two-step successive transfer has been studied. Present analysis suggests dominance of cluster transfer of a di-neutron. The contribution from the two-step sequential processes is less significant, however, the combined “two-step plus simultaneous (microscopic)” calculations give a reasonably good agreement with the measurement. The possibility of multi-step route via projectile and target excitations and contribution from such indirect transfer paths to the present two-neutron transfer cross section has been investigated.

  5. Long-range versus short-range correlations in the two-neutron transfer reaction 64Ni(18O,16O)66Ni

    Science.gov (United States)

    Paes, B.; Santagati, G.; Vsevolodovna, R. Magana; Cappuzzello, F.; Carbone, D.; Cardozo, E. N.; Cavallaro, M.; García-Tecocoatzi, H.; Gargano, A.; Ferreira, J. L.; Lenzi, S. M.; Linares, R.; Santopinto, E.; Vitturi, A.; Lubian, J.

    2017-10-01

    Recently, various two-neutron transfer studies using the (18O,16O) reaction were performed with a large success. This was achieved because of a combined use of the microscopic quantum description of the reaction mechanism and of the nuclear structure. In the present work we use this methodology to study the two-neutron transfer reaction of the 18O+64Ni system at 84 MeV incident energy, to the ground and first 2+ excited state of the residual 66Ni nucleus. All the experimental data were measured by the large acceptance MAGNEX spectrometer at the Instituto Nazionale di Fisica Nucleare -Laboratori Nazionali del Sud (Italy). We have performed exact finite range cross section calculations using the coupled channel Born approximation (CCBA) and coupled reaction channel (CRC) method for the sequential and direct two-neutron transfers, respectively. Moreover, this is the first time that the formalism of the microscopic interaction boson model (IBM-2) was applied to a two-neutron transfer reaction. From our results we conclude that for two-neutron transfer to the ground state of 66Ni, the direct transfer is the dominant reaction mechanism, whereas for the transfer to the first excited state of 66Ni, the sequential process dominates. A competition between long-range and short-range correlations is discussed, in particular, how the use of two different models (Shell model and IBM's) help to disentangle long- and short-range correlations.

  6. Can we screen phosphorus movement in the landscape through the analysis of δ"1"8O isotopic abundance in phosphate?

    International Nuclear Information System (INIS)

    Heiling, M.; Aigner, M.; Slaets, J.; Dercon, G.

    2016-01-01

    The SWMCNL explored the possibility of using δ18O isotopic signature in phosphate for screening phosphorus (P) movement in the landscape. Phosphorus is essential for crop production, but extensive use of P fertilizer and animal manure can lead to eutrophication of rivers and lakes. To study these effects, numerous studies on P movement in the soil plant system and P transformation processes have been performed in the past decades. Assessing losses of P through erosion processes, however, is challenging – particularly at the landscape level and on a longer timescale. Using the isotopic signature of stable oxygen isotope ("1"8O) in the phosphate ion as a tracer could be a cost-effective way to study P movements. This approach is already applied as a paleotemperature proxy (the fractionation between phosphate and water is temperature dependent) and can be used for quantifying P losses through leaching into surface and groundwater, as oxygen exchange between phosphate and water is slow in the absence of biological activity.

  7. 87Sr/86Sr and 18O/16O ratios, interstitial water chemistry and diagenesis in deep-sea carbonate sediments of the Ontong Java Plateau

    International Nuclear Information System (INIS)

    Elderfield, H.; Oldfield, R.K.; Hawkesworth, C.J.

    1982-01-01

    Interstitial waters and sediments from DSDP sites 288 and 289 contain information on the chemistry and diagenesis of carbonate in deep-sea sediments and on the role of volcanic matter alteration processes. Sr/Ca ratios are species dependent in unaltered foraminifera from site 289 and atom ratios exceed those predicted by distribution coefficient data. During diagenesis Sr/Ca ratios of carbonates decrease and reach the theoretical distribution at a depth which is identical to the depth of Sr isotopic equilibration, where 87 Sr/ 86 Sr ratios of interstitial waters and carbonates converge. Mg/Ca ratios in the carbonates do not increase with depth as found in some other DSDP sites, possibly because of diagenetic re-equilibration with interstitial waters showing decreasing Mg 2+ /Ca 2+ ratios with depth due to Ca input and Mg removal by alteration of volcanic matter. Interstitial 18 O/ 16 O ratios increase with depth at site 289 to delta 18 O = 0.67 per thousand (SMOW), reflecting carbonate recrystallization at elevated temperatures, the first recorded evidence of this effect in interstitial waters. Interstitial Sr 2+ concentrations reach high levels, up to 1 mM, chiefly because of carbonate recrystallization. However, 87 Sr/ 86 Sr ratios decrease from 0.7092 to less than 0.7078, lower than for contemporaneous sea water, showing that there is a volcanic input of strontium at depth. (author)

  8. Stable isotope (2H, 17O, 18O) and hydro chemical patterns of precipitation collected in weekly resolution at Hannover, Germany

    Science.gov (United States)

    Koeniger, Paul; Himmelsbach, Thomas

    2016-04-01

    Long-term observations of stable isotopes (δ18O and δ2H) in precipitation were initiated in May 2008 at the Federal Institute of Geosciences and Natural Resources (BGR) in Hannover, Germany. In 2014 all precipitation samples were re-analyzed because a purchase of a new laser spectrometer (Picarro L2140-i) now allowed measurements of δ17O and a calculation of the 17O-excess parameter. Starting in October 2015 a routine analysis of hydro chemical parameters was added whenever enough sample aliquot was available (major ions, trace elements). A discussion of the stable isotope data of the seven year series of weekly precipitation samples (n = 370) will be presented. Beneath general patterns (seasonality and trends) we also focus on importance of amount weighing procedures, corrections for minor rain amounts, aspects of sample storage and re-analyzes, as well as impacts through changes in analytical equipment (IRMS, CRD spectroscopy) which is visible from the data. For stable isotopes a Thermo Fisher delta plus IRMS (Gasbench and H-Device) was used until 2011 and from 2012 on a Picarro L2120-i water vapor analyzer with long-term accuracies for quality check samples better than 0.2‰ and 0.8‰ for δ18O and δ2H, respectively.

  9. Anomalous flow below 2700 m in the EPICA Dome C ice core detected using δ18O of atmospheric oxygen measurements

    Directory of Open Access Journals (Sweden)

    M. Leuenberger

    2007-06-01

    Full Text Available While there are no indications of mixing back to 800 000 years in the EPICA Dome C ice core record, comparison with marine sediment records shows significant differences in the timing and duration of events prior to stage 11 (~430 ka, thousands of years before 1950. A relationship between the isotopic composition of atmospheric oxygen (δ18O of O2, noted δ18Oatm and daily northern hemisphere summer insolation has been observed for the youngest four climate cycles. Here we use this relationship with new δ18O of O2 measurements to show that anomalous flow in the bottom 500 m of the core distorts the duration of events by up to a factor of 2. By tuning δ18Oatm to orbital precession we derive a corrected thinning function and present a revised age scale for the interval corresponding to Marine Isotope Stages 11–20 in the EPICA Dome C ice core. Uncertainty in the phasing of δ18Oatm with respect to insolation variations in the precession band limits the accuracy of this new agescale to ±6 kyr (thousand of years. The previously reported ~30 kyr duration of interglacial stage 11 is unchanged. In contrast, the duration of stage 15.1 is reduced by a factor of 2, from 31 to 16 kyr.

  10. Interaction of actinide ions with [NaP5W30O110]14- and [P2W18O62]6-

    International Nuclear Information System (INIS)

    Choppin, G.R.; Wall, D.E.

    2003-01-01

    Stability constants (log β 101 ) of Th 4+ , UO 2 2+ , NpO 2 + and Am 3+ with [NaP 5 W 30 O 110 ] 14- were determined by solvent extraction (μ = 0.1M NaCl) and found to be 6.18 ± 0.07, 3.80 ± 0.06, 2.98 ± 0.04, and 5.85 ± 0.05, respectively. The order of stability constants: Th 4+ > Am 3+ > UO 2 2+ > NpO 2 + is due to electrostatic repulsion between the actinyl oxygens and oxygens on the polyoxometalate surface. The order of stability constants for metal complexes with [P 2 W 18 O 62 ] 6- is Th 4+ > UO 2 2+ > Eu 3+ >NpO 2 + because the steric repulsion between actinyl oxygens and oxygens on polyoxometalate are less important. Enthalpies of complexation were measured by calorimetric titration of Th 4+ , UO 2 2+ , Nd 3+ with [NaP 5 W 30 O 110 ] 14- and [P 2 W 18 O 62 ] 6- . The results indicate that the conformation and charge distribution of the microscopic surface structures are important factors in the formation of pseudocolloids. (author)

  11. Voltammetry coupled to mass spectrometry in the presence of isotope {sup 18}O labeled water for the prediction of oxidative transformation pathways of activated aromatic ethers: Acebutolol

    Energy Technology Data Exchange (ETDEWEB)

    Bussy, Ugo; Tea, Illa [LUNAM Université de Nantes, CNRS, Chimie et Interdisciplinarité: Synthèse, Analyse et Modélisation (CEISAM), UMR 6230, 2 rue de la Houssinière, BP 92208, F-44322 Nantes cedex 3 (France); Ferchaud-Roucher, Véronique; Krempf, Michel [Université de Nantes, Plateforme Spectrométrie de Masse, CRNH, SFR Santé F. Bonamy, Institut du Thorax, UMR S1087, IRT-UN, BP 70721, 8 Quai Moncousu, 44007 Nantes cedex 1 (France); Silvestre, Virginie; Galland, Nicolas [LUNAM Université de Nantes, CNRS, Chimie et Interdisciplinarité: Synthèse, Analyse et Modélisation (CEISAM), UMR 6230, 2 rue de la Houssinière, BP 92208, F-44322 Nantes cedex 3 (France); Jacquemin, Denis [LUNAM Université de Nantes, CNRS, Chimie et Interdisciplinarité: Synthèse, Analyse et Modélisation (CEISAM), UMR 6230, 2 rue de la Houssinière, BP 92208, F-44322 Nantes cedex 3 (France); Institut Universitaire de France, 103, Boulevard Saint-Michel, 75005 Cedex 5 France (France); Andresen-Bergström, Moa; Jurva, Ulrik [CVGI iMed DMPK, AstraZeneca R and D Mölndal, Mölndal (Sweden); and others

    2013-01-31

    Highlights: ► Voltammetry coupled to mass spectrometry method as a useful tool for on-line predictions of electrochemical transformations. ► Evidence of the O-dealkoxylation reaction pathway of acebutolol in the presence of labeled water. ► New approach for on line EC-MS applications. -- Abstract: The coupling between an electrochemical cell (EC) and a mass spectrometer (MS) is a useful screening tool (EC-MS) to study the oxidative transformation pathways of various electroactive species. For that purpose, we showed that the EC-MS method, carried out in the presence and absence of isotope {sup 18}O labeled water leads not only to a fast identification of oxidation products but also leads to a fast elucidation of the mechanism pathway reaction. We examined herein the case of the electrochemical hydrolysis of activated aromatic ether. Acebutolol (β-blockers) was selected herein as model of activated aromatic ether, and its electrochemical oxidation was examined in both the presence and absence of isotope {sup 18}O labeled water. To elucidate electrochemical hydrolysis pathway reaction: O-dealkylation or O-dealkoxylation, our approach was used to prove its applicability. The electrochemical oxidation mechanism was then elucidated showing an O-dealkoxylation reaction. In addition, density functional theory (DFT) calculations fully support the experimental conclusions.

  12. Increasing aridity threats to Himalayan alpine ecosystems? A millenial history of hydroclimate from the Tibetan plateau derived from a δ18O tree-ring network

    Science.gov (United States)

    Griessinger, J.

    2015-12-01

    The Tibetan plateau (TP) plays an important role as an elevated heat source responsible for the establishment of the Asias monsoonal systems. Besides the Indian Summer Monsoon (ISM), also the East Asian Summer Monsoon (EASM) is triggering the regional precipitation regimes during the vegetation period from May to September. Within recent decades, fundamental climate changes on the southeastern part of the TP were detected leading to substantial changes within the regional hydrological budget and affecting local ecosystems. By using a spatial network of multicentennial to 1.5 millenial year old tree-ring δ18O time-series from the southeastern part of the TP, the regional climate history as well as the late Holocene monsoonal variability will be presented. Since the main climatically sensitive periods like the Medieval Warm Period and the Little Ice Age are displayed in all chronologies, their typical hydroclimatological characteristics and impacts will be discussed especially in regard to the recent warming trend on the TP and the responsible climatic triggers. Arising from these results, regional impacts and differences of the proposed hydrological changes will be discussed. In addition, first results of a comparison between proxy-based (δ18O) and model-based (re-analysis datasets) trajectory calculations will be presented, trying to give insights in the origin and impact of air masses for the most striking last three decades on the southeastern part of the TP.

  13. Study of 24Mg(18O,16O)26Mg reaction at Esub(180)=50MeV including scattering in entrance and exit channel

    International Nuclear Information System (INIS)

    Bernas, M.; Pougheon, F.; Roy-Stephan, M.; Berg, G.P.A.; Kernforschungsanlage Juelich G.m.b.H.; Berthier, B.; Le Fevre, J.P.; Wildenthal, B.H.

    1980-01-01

    Cross section angular distributions of 24 Mg( 18 O, 16 O) 26 Mg reaction at 50 MeV incident energy leading to the first four excited states in 26 Mg and the elastic and inelastic scattering for 18 O + 24 Mg at 50 MeV and 16 O + 26 Mg at 56 MeV have been measured in order to investigate the reaction mechanism of the two-nucleon transfer reaction including the analysis of incident and exit channels. The measured angular distributions were analyzed in the framework of the EFR-DWBA. Two neutron transfer amplitudes were determined using the 2s-1d shell model amplitudes calculated by Chung and Wildenthal. The large experimental cross section in contrast to the smallness of the direct transfer amplitude and the peculiar shape of the measured angular distribution of the lowest 2 1 + state suggests that this level is mainly excited by two-step processes. It is shown that a CCBA calculation describes successfully the angular distributions of the ground state and the 2 1 + state in 26 Mg

  14. Hydrogeochemical and Isotopic Characteristics of Tufa Precipitating Wates: A Case Study of the River Krka (Slovenia)

    Energy Technology Data Exchange (ETDEWEB)

    Zavadlav, S.; Lojen, S. [Jozef Stefan Institute, Department of Environmental Sciences, Ljubljana (Slovenia)

    2013-07-15

    The geochemical and stable isotope composition of tufa precipitating water in the River Krka in the Slovenian karst area were studied. Surface water chemistry in the River Krka is controlled by groundwater interactions with carbonate rocks, soil CO{sub 2} and meteoric water in the aquifer. Major element chemistry of water is controlled by dissolution of dolomite and calcite. The aquifer is the main source of cations, since concentrations of Mg{sup 2+}, Sr{sup 2+} and Ba{sup 2+} in water are highest at the spring. Ca{sup 2+} concentrations are slightly increasing due to the additional mixing of surface and groundwater downstream. Oxygen isotope composition of water indicates homogenization of meteoric water in the aquifer, while {delta}{sup 13}C values of dissolved inorganic carbon in water are affected by biological activity in the soil. {delta}{sup 18}O and {delta}{sup 13}C of bulk tufa show that deposition of tufa precipitates in the River Krka is kinetically controlled resulting in enrichment with heavier isotopes. Calculated equilibrium temperature of tufa precipitation based on the oxygen isotope composition of water and tufa fit with measured water temperature when average {delta}{sup 18}O values of water and tufa are considered. (author)

  15. Seasonal Variations in Stable Isotope Ratios of Oxygen and Hydrogen in Two Tundra Rivers in NE European Russia

    Energy Technology Data Exchange (ETDEWEB)

    Huitu, E.; Arvola, L. [Lammi Biological Station, University of Helsinki (Finland); Sonninen, E. [Radiocarbon Dating Laboratory, University of Helsinki (Finland)

    2013-07-15

    The variability in stable isotope ratios of oxygen and hydrogen ({delta} {sup 18}O and {delta}{sup 2}H values) in river waters in northeast European Russia was studied for the period from July 2007 to october 2008. Exceptional isotope composition in precipitation obtained during the sampling period was clearly traced in the composition of river waters. Water from permafrost thawing did not make a great contribution to river flow. (author)

  16. Stable isotope composition of inorganic carbonates from Lake Abiyata (Ethiopia): Attempt of reconstructing δ18O palaeohydrological changes during the Holocene

    International Nuclear Information System (INIS)

    Gibert, E.; Massault, M.; Travi, Y.; Chernet, T.

    2002-01-01

    Due to the sensitivity of its regional climate to the African monsoon seasonal shifting, Ethiopia has been designated as a key site for palaeoenvironmental reconstructions mainly within the IGBP-PAGES-PEPIII programme. Under the French-Ethiopian ERICA project, we focused on Lake Abiyata located in the Ziway-Shala basin (Central Ethiopia) which has experienced several lacustrine highstands during the Late Pleistocene and Holocene. At present, Lake Abiyata is a closed lake with a very flat catchment area, and corresponds to a half, deep graben infilled by 600-m of sedimentary deposits. In 1995, a 12.6-m-long sequence ABII was cored in Lake Abiyata. A reliable 14 C-AMS chronology was defined on both organic matter and inorganic carbonates. Both the modern hydrologeological and geochemical balances of the 'groundwater-lake' system indicate that (i) carbonate cristallization mainly occurs at the water-sediment interface via the mixing of lake water and 14 C-depleted groundwaters, and that (ii) modern algae form in equilibrium with the atmospheric reservoir. Phytoplankton is thus considered as an authigenic material, and Core ABII has registered 13,500 cal. yr B.P. of environmental history. The evidence of calcite precipitation at the water-sediment interface calls into question the direct palaeoclimatic reconstruction based on inorganic carbonates. Since the evolution of isotopic contents of carbonates might be linked to the variable proportion of the 'lake/groundwater' end-members in the mixing, calculations based on isotopic mass balance models may allow for the reconstruction of δ 18 O composition of the lake water. Two major changes can be highlighted: (i) the ∼12,000-5500 cal. yr B.P. period is associated to low 18 O contents of lake water, and corresponds to an open hydrological system, with a high lacustrine phytoplanktonic productivity, and (ii) from ∼5500 cal. yr B.P. to Present, regressive conditions are suggested by the δ 18 O enrichment of the lake

  17. Localization of groundwater infiltration in the combined sewers of Brussels by stable isotopes measurements (δ18O, δD) by Cavity Ring Down Spectroscopy.

    Science.gov (United States)

    De Bondt, Kevin; Claeys, Philippe

    2014-05-01

    In the last 20 years research has been conducted to quantify the infiltration of groundwater into the sewers. This groundwater, called parasitic water, increases the volume of waste-water to be treated and consequently the cost of this treatment. Moreover, in the case of combined sewer systems, the parasitic water also limits the sewer capacity and indirectly increases the risks of combined sewer overflows and floods. The infiltration of groundwater occurs trough cracks, sewer collapses and from direct connections with old springs. Different methods quantify the intrusion of parasitic water. Among these, the use of the stable isotopes of water (δ18O & δD) shows good result in catchments or cities close to Mountainous regions (example from Lyon, Zurich), where isotopic signals vary significantly because of continental and altitude effects. However many cities, such as Brussels, are located in more oceanic settings and theoretically offer less potential for the application of the stable isotopes method. In the case of Brussels, river-water from the Meuse is used to produce domestic-water. The catchment of this river extends into the Ardennes, which are affected by slightly different climatic conditions. δ18O & δD analyzes of groundwater from the main aquifer (Ledo-Paniselian-Brusselian) and domestic-water from the Callois reservoir fed by the Meuse River show sufficient isotopic differences in the south of Brussels, but only during the summer. The discrimination potential is better with δD than with δ18O. The improvement of δD measurements (precision, costs,...) brought by Cavity Ring Down Spectroscopy largely contributes to the potential of using stable isotopes method to trace water in Brussels. The first campaigns in the sewers also show a little enrichment (in heavy isotopes) of the waste-water in comparison with the reservoir waters and tap waters. This increases the potential of the method but constrains the sampling to pure waste-water in sewer segments

  18. Isotopic Characterization of Snow, Ice and Glacial Melt in the Western Himalayas, India

    Energy Technology Data Exchange (ETDEWEB)

    Rai, S. P.; Kumar, B.; Arora, M.; Singh, R. D. [National Institute of Hydrology, Roorkee, 247 667 (India)

    2013-07-15

    Precipitation and glacial melt samples were collected at the snout of the Gangotri Glacier, popularly known as Gaumukh, located in the western Himalayas, India. Snow and ice samples were collected from different sites of the Gangotri Glacier. The local meteoric water line (LMWL) developed for the ablation period (May to October) is {delta}{sup 2}H = 8.2 {delta}{sup 18}O + 17.1 (r{sup 2} = 0.99), which shows a slightly higher slope and intercept than GMWL. This may be due to local summer connective precipitation occurring under dry climatic conditions and mountainous region moisture recycling with the south-west monsoon. The meltwater line, {delta}{sup 2}H =9.4 {delta}{sup 18}O + 37.5 (r{sup 2}= 0.96), having a significantly higher slope and intercept than the GMWL and LMWL. The main reasons for the higher slope and intercept of meltwater line may be due to the recycling of local vapour with moisture derived from the Western disturbance moisture whose source is the Mediterranean sea. The high d-exess values of snow, ice and meltwater indicate that the source of moisture is the Western disturbances. (author)

  19. Isotopic Composition and Age of Surface Water as Indicators of Groundwater Sustainability in a Semiarid Area: Case of the Souss Basin (Morocco)

    Energy Technology Data Exchange (ETDEWEB)

    Bouchaou, L.; Tagma, T.; Boutaleb, S.; Hsissou, Y. [LAGAGE Laboratory, Ibn Zohr University, Agadir (Morocco); Nathaniel, W.; Vengosh, A. [Duke University (United States); Michelot, J. L.; Massault, M. [UMR ' IDES' , CNRS - Universite Paris-Sud, Orsay (France); Elfaskaoui, M. [Hydraulic Agency of Souss-Massa-Draa Basins, Agadir (Morocco)

    2013-07-15

    This study aims to determine the surface water and groundwater interconnection in the Souss catchment of western Morocco by applying multiple isotopic tracers such as {delta}{sup 18}O, {delta}{sup 2}H, {sup 3}H, Ra, {sup 14}C, {sup 87}Sr/{sup 86}Sr and CFCs. Stable water isotope data indicate that the High Atlas Mountains, with their high rainfall and low {delta}{sup 18}O and {delta}{sup 2}H values, constitute the major source of recharge to the Souss-Massa aquifer. Carbon-{sup 14} activities (34-94 pMC) and {sup 3}H indicate a long residence time of groundwater in some areas. The high {sup 14}C activities measured in the Ifni spring located at 2158 m a.s.l. and the Tiar spring at 711 m a.s.l. indicate a modern contribution, which is consistent with recharge from the High Atlas tributaries. In the upstream mountainous section, the mass balance mixing model suggest that groundwater contribution to stream flow is about 72% during the wet season and 36% during the dry season. In the downstream plain, 80% of surface flow infiltrates to the aquifer. {sup 226}Ra and {sup 87}Sr/{sup 86}Sr variations were indistinguishable for surface waters and groundwater. (author)

  20. Neutron-rich nuclei produced at zero degrees in damped collisions induced by a beam of 18O on a 238U target

    Science.gov (United States)

    Stefan, I.; Fornal, B.; Leoni, S.; Azaiez, F.; Portail, C.; Thomas, J. C.; Karpov, A. V.; Ackermann, D.; Bednarczyk, P.; Blumenfeld, Y.; Calinescu, S.; Chbihi, A.; Ciemala, M.; Cieplicka-Oryńczak, N.; Crespi, F. C. L.; Franchoo, S.; Hammache, F.; Iskra, Ł. W.; Jacquot, B.; Janssens, R. V. F.; Kamalou, O.; Lauritsen, T.; Lewitowicz, M.; Olivier, L.; Lukyanov, S. M.; Maccormick, M.; Maj, A.; Marini, P.; Matea, I.; Naumenko, M. A.; de Oliveira Santos, F.; Petrone, C.; Penionzhkevich, Yu. E.; Rotaru, F.; Savajols, H.; Sorlin, O.; Stanoiu, M.; Szpak, B.; Tarasov, O. B.; Verney, D.

    2018-04-01

    Cross sections and corresponding momentum distributions have been measured for the first time at zero degrees for the exotic nuclei obtained from a beam of 18O at 8.5 MeV/A impinging on a 1 mg/cm2238U target. Sizable cross sections were found for the production of exotic species arising from the neutron transfer and proton removal from the projectile. Comparisons of experimental results with calculations based on deep-inelastic reaction models, taking into account the particle evaporation process, indicate that zero degree is a scattering angle at which the differential reaction cross section for production of exotic nuclei is at its maximum. This result is important in view of the new generation of zero degrees spectrometers under construction, such as the S3 separator at GANIL, for example.

  1. From bismuth oxide/hydroxide precursor clusters towards stable oxides: Proton transfer reactions and structural reorganization govern the stability of [Bi18O13(OH)10]-nitrate clusters

    Science.gov (United States)

    Walther, M.; Zahn, D.

    2018-01-01

    Structural relaxation and stability of a Bi18-cluster as obtained from association of [Bi6O4(OH)4](NO3)6 precursor clusters in DMSO solution is investigated from a combination of quantum chemical calculations and μs-scale molecular dynamics simulations using empirical interaction potentials. The Bi18-cluster undergoes a OH⋯OH proton transfer reaction, followed by considerable structural relaxation. While the aggregation of the Bi18-cluster is induced by the dissociation of a single nitrate ion leading to [Bi6O4(OH)4](NO3)5+ as an activated precursor species that can bind two more Bi6-clusters, we find the [Bi18O13(OH)10](NO3)18-x+x species (explored for x = 1-6) rather inert against either nitrate dissociation, collision with Bi6-precursors or combinations thereof.

  2. Investigation of luminescence mechanism in La{sub 0.2}Y{sub 1.8}O{sub 3} scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Sahi, Sunil [Department of Physics, The University of Texas at Arlington, Arlington, TX 76019-0059 (United States); Wang, Zhiqiang [Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7 (Canada); Luo, Junming [School of Materials Science and Engineering, Nanchang Hangkong University, Nanchang 330063 (China); Groza, Michael [Department of Life and Physical Sciences, Fisk University, Nashville, TN 37208-3051 (United States); Li, Jiang [Key Laboratory of Transparent Opto-functional Inorganic Materials, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Zhang, Junying [Department of Physics, Beihang University, Beijing 100191 (China); Chen, Wei, E-mail: weichen@uta.edu [Department of Physics, The University of Texas at Arlington, Arlington, TX 76019-0059 (United States); Pan, Yubai [Key Laboratory of Transparent Opto-functional Inorganic Materials, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Burger, Arnold [Department of Life and Physical Sciences, Fisk University, Nashville, TN 37208-3051 (United States); Sham, Tsun-Kong [Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7 (Canada)

    2016-05-15

    La{sub 0.2}Y{sub 1.8}O{sub 3} is a new and promising scintillator which is based on the host material without doping. Here the time gated X-ray excited optical luminescence is measured by using the excitation energy below, above and at the La L{sub 3}-edge. A relatively slow and broad emission with peak at 415 nm has been observed as the dominant emission. Also, a weak emission at 360 nm is observed at the fast window, associated with the recombination of trapped excitons in Y{sub 2}O{sub 3} host. The observations show that the broad emission at 415 nm is most likely due to the recombination of trapped excitons associated with the La{sup 3+} doping into Y{sub 2}O{sub 3} sites.

  3. Use of [18O4] phosphoric acid in the quantitation of phosphate by gas-liquid chromatography-mass spectrometry analysis

    International Nuclear Information System (INIS)

    Graff, G.; Krick, T.P.; Walseth, T.F.; Goldberg, N.D.

    1980-01-01

    A procedure is described to quantitate inorganic phosphate in the form of the tris(trimethylsilyl) (TMS) phosphate by gas-liquid chromatography-mass spectrometry (glc-ms) that increases the previously reported detection limit from the microgram to the nanogram range. The sensitivity for detecting TMS-phosphate by glc-ms analysis was shown to be limited by an increasing fractional loss with decreasing concentrations of TMS-phosphate analyzed due to its adsorption on different types of glc column supports. The method developed employs [ 18 O 4 ] phosphoric acid which serves as both an internal standard to permit quantitation and as a carrier to minimize sample adsorption on the glc column support

  4. Formation of 238U16O and 238U18O observed by time-resolved emission spectroscopy subsequent to laser ablation

    Science.gov (United States)

    Weisz, David G.; Crowhurst, Jonathan C.; Siekhaus, Wigbert J.; Rose, Timothy P.; Koroglu, Batikan; Radousky, Harry B.; Zaug, Joseph M.; Armstrong, Michael R.; Isselhardt, Brett H.; Savina, Michael R.; Azer, Magdi; Finko, Mikhail S.; Curreli, Davide

    2017-07-01

    We have measured vibronic emission spectra of an oxide of uranium formed after laser ablation of the metal in gaseous oxygen. Specifically, we have measured the time-dependent relative intensity of a band located at approximately 593.6 nm in 16O2. This band grew in intensity relative to neighboring atomic features as a function time in an oxygen environment but was relatively invariant with time in argon. In addition, we have measured the spectral shift of this band in an 18O2 atmosphere. Based on this shift, and by comparison with earlier results obtained from free-jet expansion and laser excitation, we can confirm that the oxide in question is UO, consistent with recent reports based on laser ablation in 16O2 only.

  5. Natural chlorate in the environment: Application of a new IC-ESI/MS/MS method with a Cl18O3- internal standard

    Science.gov (United States)

    Rao, Balaji; Hatzinger, Paul B.; Böhlke, John Karl; Sturchio, Neil C.; Andraski, Brian J.; Eckardt, Frank D.; Jackson, W. Andrew

    2010-01-01

    A new ion chromatography electrospray tandem mass spectrometry (IC-ESI/MS/MS) method has been developed for quantification and confirmation of chlorate (ClO3−) in environmental samples. The method involves the electro-chemical generation of isotopically labeled chlorate internal standard (Cl18O3−) using 18O water (H218O). The standard was added to all samples prior to analysis thereby minimizing the matrix effects that are associated with common ions without the need for expensive sample pretreatments. The method detection limit (MDL) for ClO3− was 2 ng L−1 for a 1 mL volume sample injection. The proposed method was successfully applied to analyze ClO3− in difficult environmental samples including soil and plant leachates. The IC-ESI/MS/MS method described here was also compared to established EPA method 317.0 for ClO3− analysis. Samples collected from a variety of environments previously shown to contain natural perchlorate (ClO4−) occurrence were analyzed using the proposed method and ClO3− was found to co-occur with ClO4− at concentrations ranging from 500 mg kg−1 in caliche salt deposits from the Atacama Desert in Chile. Relatively low concentrations of ClO3− in some natural groundwater samples (<0.1 μg L−1) analyzed in this work may indicate lower stability when compared to ClO4− in the subsurface. The high concentrations of ClO3− in caliches and soils (3−6 orders of magnitude greater) as compared to precipitation samples indicate that ClO3−, like ClO4−, may be atmospherically produced and deposited, then concentrated in dry soils, and is possibly a minor component in the biogeochemical cycle of chlorine.

  6. The interaction of soil phototrophs and fungi with pH and their impact on soil CO2, CO18O and OCS exchange.

    Science.gov (United States)

    Sauze, Joana; Ogée, Jérôme; Maron, Pierre-Alain; Crouzet, Olivier; Nowak, Virginie; Wohl, Steven; Kaisermann, Aurore; Jones, Sam P; Wingate, Lisa

    2017-12-01

    The stable oxygen isotope composition of atmospheric CO 2 and the mixing ratio of carbonyl sulphide (OCS) are potential tracers of biospheric CO 2 fluxes at large scales. However, the use of these tracers hinges on our ability to understand and better predict the activity of the enzyme carbonic anhydrase (CA) in different soil microbial groups, including phototrophs. Because different classes of the CA family (α, β and γ) may have different affinities to CO 2 and OCS and their expression should also vary between different microbial groups, differences in the community structure could impact the 'community-integrated' CA activity differently for CO 2 and OCS. Four soils of different pH were incubated in the dark or with a diurnal cycle for forty days to vary the abundance of native phototrophs. Fluxes of CO 2 , CO 18 O and OCS were measured to estimate CA activity alongside the abundance of bacteria, fungi and phototrophs. The abundance of soil phototrophs increased most at higher soil pH. In the light, the strength of the soil CO 2 sink and the CA-driven CO 2 -H 2 O isotopic exchange rates correlated with phototrophs abundance. OCS uptake rates were attributed to fungi whose abundance was positively enhanced in alkaline soils but only in the presence of increased phototrophs. Our findings demonstrate that soil-atmosphere CO 2 , OCS and CO 18 O fluxes are strongly regulated by the microbial community structure in response to changes in soil pH and light availability and supports the idea that different members of the microbial community express different classes of CA, with different affinities to CO 2 and OCS.

  7. UV-laser microdissection system - A novel approach for the preparation of high-resolution stable isotope records (δ13C/δ18O) from tree rings

    Science.gov (United States)

    Schollaen, Karina; Helle, Gerhard

    2013-04-01

    Intra-annual stable isotope (δ13C and δ18O) studies of tree rings at various incremental resolutions have been attempting to extract valuable seasonal climatic and environmental information or assessing plant ecophysiological processes. For preparing high-resolution isotope samples normally wood segments or cores are mechanically divided in radial direction or cut in tangential direction. After mechanical dissection, wood samples are ground to a fine powder and either cellulose is extracted or bulk wood samples are analyzed. Here, we present a novel approach for the preparation of high-resolution stable isotope records from tree rings using an UV-laser microdissection system. Firstly, tree-ring cellulose is directly extracted from wholewood cross-sections largely leaving the wood anatomical structure intact and saving time as compared to the classical procedure. Secondly, micro-samples from cellulose cross-sections are dissected with an UV-Laser dissection microscope. Tissues of interest from cellulose cross-sections are identified and marked precisely with a screen-pen and dissected via an UV-laser beam. Dissected cellulose segments were automatically collected in capsules and are prepared for stable isotope (δ13C and δ18O) analysis. The new techniques facilitate inter- and intra-annual isotope analysis on tree-ring and open various possibilities for comparisons with wood anatomy in plant eco-physiological studies. We describe the design and the handling of this novel methodology and discuss advantages and constraints given by the example of intra-annual oxygen isotope analysis on tropical trees.

  8. Properties of Dense Cores Embedded in Musca Derived from Extinction Maps and {sup 13}CO, C{sup 18}O, and NH{sub 3} Emission Lines

    Energy Technology Data Exchange (ETDEWEB)

    Machaieie, Dinelsa A.; Vilas-Boas, José W.; Wuensche, Carlos A. [Instituto Nacional de Pesquisas Espaciais, Av. dos Astronautas 1.758—Jardim da Granja, CEP-12227-010, São José dos Campos, SP (Brazil); Racca, Germán A. [Universidade do Estado do Rio Grande do Norte, Faculdade de Ciências Exatas e Naturais/Depto. de Física, Campus Universitário Central, Setor II BR 110, KM 48, Rua Prof. António Campos, Costa e Silva 59610-090—Mossoró-RN (Brazil); Myers, Philip C. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Hickel, Gabriel R., E-mail: dinelsa.machaieie@inpe.br [Universidade Federal de Itajubá, Departamento de Física, Av. BPS, 1303, Pinheirinho, Itajubá, MG (Brazil)

    2017-02-10

    Using near-infrared data from the Two Micron All Sky Survey catalog and the Near Infrared Color Excess method, we studied the extinction distribution in five dense cores of Musca, which show visual extinction greater than 10 mag and are potential sites of star formation. We analyzed the stability in four of them, fitting their radial extinction profiles with Bonnor–Ebert isothermal spheres, and explored their properties using the J = 1–0 transition of {sup 13}CO and C{sup 18}O and the J = K = 1 transition of NH{sub 3}. One core is not well described by the model. The stability parameter of the fitted cores ranges from 4.5 to 5.7 and suggests that all cores are stable, including Mu13, which harbors one young stellar object (YSO), the IRAS 12322-7023 source. However, the analysis of the physical parameters shows that Mu13 tends to have larger A {sub V}, n {sub c}, and P {sub ext} than the remaining starless cores. The other physical parameters do not show any trend. It is possible that those are the main parameters to explore in active star-forming cores. Mu13 also shows the most intense emission of NH{sub 3}. Its {sup 13}CO and C{sup 18}O lines have double peaks, whose integrated intensity maps suggest that they are due to the superposition of clouds with different radial velocities seen in the line of sight. It is not possible to state whether these clouds are colliding and inducing star formation or are related to a physical process associated with the formation of the YSO.

  9. A Fiji multi-coral δ18O composite approach to obtaining a more accurate reconstruction of the last two-centuries of the ocean-climate variability in the South Pacific Convergence Zone region

    Science.gov (United States)

    Dassié, Emilie P.; Linsley, Braddock K.; Corrège, Thierry; Wu, Henry C.; Lemley, Gavin M.; Howe, Steve; Cabioch, Guy

    2014-12-01

    The limited availability of oceanographic data in the tropical Pacific Ocean prior to the satellite era makes coral-based climate reconstructions a key tool for extending the instrumental record back in time, thereby providing a much needed test for climate models and projections. We have generated a unique regional network consisting of five Porites coral δ18O time series from different locations in the Fijian archipelago. Our results indicate that using a minimum of three Porites coral δ18O records from Fiji is statistically sufficient to obtain a reliable signal for climate reconstruction, and that application of an approach used in tree ring studies is a suitable tool to determine this number. The coral δ18O composite indicates that while sea surface temperature (SST) variability is the primary driver of seasonal δ18O variability in these Fiji corals, annual average coral δ18O is more closely correlated to sea surface salinity (SSS) as previously reported. Our results highlight the importance of water mass advection in controlling Fiji coral δ18O and salinity variability at interannual and decadal time scales despite being located in the heavy rainfall region of the South Pacific Convergence Zone (SPCZ). The Fiji δ18O composite presents a secular freshening and warming trend since the 1850s coupled with changes in both interannual (IA) and decadal/interdecadal (D/I) variance. The changes in IA and D/I variance suggest a re-organization of climatic variability in the SPCZ region beginning in the late 1800s to period of a more dominant interannual variability, which could correspond to a southeast expansion of the SPCZ.

  10. Environmental isotopes (18O, 2H, and 87Sr/86Sr) as a tool in groundwater investigations in the Keta Basin, Ghana

    Science.gov (United States)

    Jørgensen, Niels; Banoeng-Yakubo, Bruce

    2001-03-01

    Analyses of environmental isotopes (18O, 2H, and 87Sr/86Sr) are applied to groundwater studies with emphasis on saline groundwater in aquifers in the Keta Basin, Ghana. The 87Sr/86Sr ratios of groundwater and surface water of the Keta Basin primarily reflect the geology and the mineralogical composition of the formations in the catchments and recharge areas. The isotopic compositions of 18O and 2H of deep groundwater have small variations and plot close to the global meteoric water line. Shallow groundwater and surface water have considerably larger variations in isotopic compositions, which reflect evaporation and preservation of seasonal fluctuations. A significant excess of chloride in shallow groundwater in comparison to the calculated evaporation loss is the result of a combination of evaporation and marine sources. Groundwaters from deep wells and dug wells in near-coastal aquifers are characterized by relatively high chloride contents, and the significance of marine influence is evidenced by well-defined mixing lines for strontium isotopes, and hydrogen and oxygen stable isotopes, with isotopic compositions of seawater as one end member. The results derived from environmental isotopes in this study demonstrate that a multi-isotope approach is a useful tool to identify the origin and sources of saline groundwater. Résumé. L'analyse des isotopes du milieu (18O, 2H, et 87Sr/86Sr) a été mise en œuvre pour des études hydrogéologiques portant sur des eaux souterraines salées des aquifères du bassin de Keta (Ghana). Les rapports isotopiques 87Sr/86Sr de l'eau souterraine et de l'eau de surface du bassin de Keta reflètent principalement la géologie et la composition minéralogique des formations des bassins d'alimentation et des zones de recharge. Les compositions isotopiques en 18O et en 2H des eaux souterraines profondes présentent de faibles variations et se placent près de la droite des eaux météoriques mondiales. Les eaux des nappes peu profondes

  11. Valuing Essays: Essaying Values

    Science.gov (United States)

    Badley, Graham

    2010-01-01

    The essay regularly comes under attack. It is criticised for being rigidly linear rather than flexible and reflective. I first challenge this view by examining reasons why the essay should be valued as an important genre. Secondly, I propose that in using the essay form students and academics necessarily exemplify their own critical values. Essays…

  12. The origins and behaviour of carbon in a major semi-arid river, the Murray River, Australia, as constrained by carbon isotopes and hydrochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Cartwright, Ian, E-mail: ian.cartwright@monash.edu [School of Geosciences, Monash University, Clayton, Vic. 3800 (Australia)] [National Centre for Groundwater Research and Training, Flinders University, Adelaide SA 5001 (Australia)

    2010-11-15

    Research highlights: {yields} {delta}{sup 13}C and concentrations of DIC in Murray River controlled by mineralisation of organic carbon and evasion. {yields} Murray River is source of atmospheric CO{sub 2}. {yields} In-river processing of carbon results in difficulties in determining carbon sources. - Abstract: {delta}{sup 13}C values of dissolved inorganic C (DIC), dissolved organic C (DOC), and particulate organic C (POC) together with {delta}{sup 18}O and {delta}{sup 2}H values of water, {delta}{sup 34}S values of dissolved SO{sub 4}, and major ion concentrations were measured in the Murray River and its tributaries between November 2005 and April 2007 to constrain the origins and behaviour of riverine C. {delta}{sup 13}C{sub DIC} values in the Murray River vary between -9.5 and -4.7 per mille with a range of <3 per mille within any sampling round. {delta}{sup 13}C{sub DIC} values of the tributaries are -11.0 per mille to -5.1 per mille. DIC concentrations of the Murray River increase from {approx}25 mg/L in the middle and upper reaches of the river to 45-55 mg/L in the lower reaches. However, the mass ratio of DIC as a proportion of the total dissolved solids (TDS) decreases from {approx}0.6-0.7 in the headwaters to {approx}0.2-0.3 in the lower reaches of the river, with similar downstream changes in DIC/Cl ratios. This precludes simple evaporative concentration of DIC and is interpreted as the river evading CO{sub 2}; this interpretation is consistent with pCO{sub 2} values that are in the range 550-11,200 ppm volume (ppmv), which are far higher than those in equilibrium with the atmosphere ({approx}360 ppmv). The {delta}{sup 13}C{sub DIC} values are similar to those that would be produced by the weathering of marine limestone ({delta}{sup 13}C {approx} 0 per mille). However, the lack of marine limestones cropping out in the Murray-Darling Basin and the relatively uniform {delta}{sup 13}C{sub DIC} values of the Murray River (even in upland reaches where the

  13. FieldSpec: A field portable mass spectrometer prototype for high frequency measurements of δ (2) H and δ (18) O ratios in water

    Science.gov (United States)

    López Días, Veneranda; Quang Hoang, Hung; Martínez-Carreras, Núria; Barnich, François; Wirtz, Tom; Pfister, Laurent; McDonnell, Jeffrey

    2016-04-01

    Hydrological studies relying on stable water isotopes to better understand water sources, flowpaths and transit times are currently limited by the coarse temporal resolution of sampling and analysis protocols. At present, two kinds of lab-based instruments are used : (i) the standard isotope ratio mass spectrometers (IRMS) [1] and (ii) the laser-based instruments [2, 3]. In both cases, samples need to be collected in the field and then transferred to the laboratory for the water isotopic ratio measurements (even further complex sample preparation is required for the IRMS). Hence, past and ongoing research targets the development of field deployable instruments for measuring stable water isotopes at high temporal frequencies. While recent studies have demonstrated that laser-based instruments may be taken to the field [4, 5], their size and power consumption still restrict their use to sites equipped with mains power or generators. Here, we present progress on the development of a field portable mass spectrometer (FieldSpec) for direct high frequency measurements of δ2H and δ18O ratios in water. The FieldSpec instrument is based upon the use of a double focusing magnetic sector mass spectrometer in combination with an electron impact ion source and a membrane dual inlet system. The instrument directly collects liquid water samples in the field, which are then converted into water vapour before being injected into the mass spectrometer for the stable isotope analysis. δ2H and δ18O are derived from the measured mass spectra. All the components are arranged in a vacuum case having a suit case type dimension with portable electronics and battery. Proof-of-concept experiments have been carried out to characterize the instrument. The results show that the FieldSpec instrument has good linearity (R2 = 0.99). The reproducibility of the instrument ranges between 1 and 4 ‰ for δ2H and between 0.1 and 0.4 ‰ for δ18O isotopic ratio measurements. A measurement

  14. Application of individual foraminifera Mg/Ca and δ18O analyses for paleoceanographic reconstructions in the Bay of Bengal and other active depositional environments

    Science.gov (United States)

    Fritz-Endres, T.; Dekens, P.; Fehrenbacher, J. S.; Spero, H. J.; Stine, A.

    2017-12-01

    Paleoceanographic research traditionally focuses on regions where sediment deposition is minimally affected by transport. However, sediment fans near tectonically active regions provide an opportunity to link oceanographic climate to terrestrial processes. Sediment cores recovered during IODP Expedition 354 in the Bay of Bengal include hemipelagic sections that record the history of tectonic uplift and the development of the Indian Monsoon through the last 10 Ma. Although these cores provide a unique opportunity to link marine and terrestrial climate, the complex depositional environment requires that the source of foraminifera is carefully considered before using these proxies to reconstruct oceanographic conditions. Foraminifera in Bengal Fan sediments may have been transported via turbidity currents from the northern Bay of Bengal, where the seasonal variability of SST and SSS is larger compared to the southern Bay of Bengal. We measured single Globigerinoides sacculifer Mg/Ca and δ18O from mudline samples of IODP Site U1454 (8.4°N, 85.5°E, 3721 m water depth) near the modern active channel and Site U1449 (8.4°N, 88.7°E, 3653 m water depth) far from channel activity. We compare these sites to single G. sacculifer from the core-top sample of Site 342KL (20.6°N, 90.1°E, 1256 m water depth) located on the continental shelf. Each foraminifera lives 2-4 weeks and the distribution of 60 to 80 data points reflects the seasonal range of SST and SSS at the location where the foraminifera calcified. Measurements in foraminifera from Site U1449 (away from active channel) are statistically different from the site in the northern Bay of Bengal and more consistent with local conditions. Conversely, foraminifera from the site near the active channel reflect a combined signal of local conditions recorded from the site far from channel activity and those recorded from the continental shelf. This suggests a portion of foraminifera from the active channel site have been

  15. Multi-tracer approach (18O, 3H/3He, CFC, SF6, 35S) to find the best emergency drinking water supply, Vorarlberg, Austria

    Science.gov (United States)

    Kralik, Martin; Vergnaud, Virginie; Uriostegui, Stephanie; Esser, Bradley

    2016-04-01

    To provide an emergency drinking water supply in case of catastrophic events (regional chemical accidents, floods, earth quakes etc.), wells and springs should be known which are fed by a large reservoir. Such reservoirs provide a good filtering capacity and long Mean Residence Times (MRTs) of the raw water. Their existence allows to use these resources for longer periods excluding the danger of contamination. This provides the water authorities the necessary time to set measures to protect the general water supply. After preselection of 16 wells and springs all over the territory of the province of Vorarlberg at the western end of Austria by the local water authority, these wells and springs were measured (water temperature, electric conductivity, pH and dissolved oxygen content) and sampled monthly for δ 18O/2H measurements over the winter half-year 2013/14. At the same time the tritium concentrations of the October and March samples were measured as well. Based on the variation of the monthly on-site measurements and the δ 18O/2H results 12 wells and springs were selected for further investigations. On these sites samples for 3H/3He, CFC-11/12/113, SF6 and sulphur-35 measurements were collected in August 2014. As expected from a humid alpine area, non of the selected springs or wells showed really long MRTs. Five out of 16 investigated sites are regarded as well suited to be used as emergency water source with a range of MRTs of 9 - 30 years. Five springs and wells are regarded of limited suitability due to the shorter MRTs of 5 - 9 years. In two springs the 3H/3He method could not be applied due to He-degassing in a karst-system and during sampling. CFC and SF6 excess at some sites with anthropogenic and geogenic sources hampered the utilisation of these gases as dating tool, but they were useful as source tracers. Sulphur-35 was detected in two wells only, indicating contribution of very young water (< 1 year). In both cases MRTs of 13 - 17 years, calculated

  16. GC-ECNICI-MS/MS of eicosanoids as pentafluorobenzyl-trimethylsilyl (TMS) derivatives: Evidence of CAD-induced intramolecular TMS ether-to-ester rearrangement using carboxy-18O-labelled eicosanoids and possible implications in quantitative analysis.

    Science.gov (United States)

    Tsikas, Dimitrios

    2017-03-15

    GC-MS and GC-MS/MS of pentafluorobenzyl (PFB) ester trimethylsilyl (TMS) ether (PFB-TMS) derivatives of hydroxylated long-chain fatty acids including arachidonic acid metabolites, the eicosanoids, in the electron-capture negative-ion chemical ionization (ECNICI) mode are the most sensitive and accurate approaches to quantify carboxyl groups-containing compounds in complex biological fluids such as plasma and urine. Under ECNICI conditions, PFB-TMS derivatives of eicosanoids ionize to form very few ions, with the carboxylates [M-PFB] - being typically the most intense. Less intense ions may be additionally formed by consecutive neutral loss (NL) of trimethylsilanol (TMSOH, 90Da) groups ([M-PFB-(TMSOH) n ] - ). By using [1,1- 18 O 2 ]- and [1,ω- 18 O 2 ]-eicosanoids, we studied ion processes following collisionally activated dissociation (CAD) of the precursor ions [M-PFB] - . We found that CAD resulted in formation of product ions due to NL of a TMS 18 OH (92Da) group in monocarboxylic and of a PFB 18 OH (200Da) group in dicarboxylic eicosanoids. TMS 18 OH NL implies an intra-molecular transfer of the TMS group from hydroxyl groups to their carboxylate anions [M-PFB] - . From a mechanistic point of view, this rearrangement may explain formation of unique product ions in GC-MS/MS of eicosanoids under ECNICI conditions. From the quantitative point of view, quantification by GC-MS/MS of product ions due to [M-PFB-(TMSOH) n ] - and [M-PFB-TMS 18 OH-(TMSOH) n-1 ] - would reveal incorrect data, if [1,1- 18 O 2 ]-eicosanoids are used as internal standards and if no correction for the 18 O-loss is performed. In 18 O-labelled dicarboxylic eicosanoids, such as the major urinary metabolite (MUM) of E prostaglandins, i.e., [1,ω- 18 O 2 ]-PGE-MUM), no TMS ester/TMS ether rearrangement was observed. Yet, 18 O-loss occurred upon CAD of [M-PFB] - due to NL of PFB 18 OH (200Da). In both cases the extent of 18 O-loss needs to be determined and considered for accurate quantification

  17. Relationship between 13C and 18O fractionation and changes in major element composition in a recent calcite-depositing spring - a model of chemical variations with inorganic CaCO3 precipitation

    International Nuclear Information System (INIS)

    Usdowski, E.; Hoefs, J.; Menschel, G.

    1979-01-01

    A theoretical model is derived in which isotopic fractionations can be calculated as a function of variations in dissolved carbonate species on CO 2 degassing and calcite precipitation. This model is tested by application to a calcite-depositing spring system near Westerhof, Germany. In agreement with the model, 13 C of the dissolved carbonate species changes systematically along the flow path. The difference in delta values between the upper and lower part of the stream is about 1%. The 13 C content of the precipitated calcite is different from that expected from the theoretical partitioning. The isotopic composition of the solid CaCO 3 is similar to that of the dissolved carbonate, though in theory it should be isotopically heavier by about 2.4%. The 18 O composition of dissolved carbonate and H 2 O is constant along the stream. Calculated calcite-water temperatures differ by about +5 0 C from the observed temperatures demonstrating isotopic disequilibrium between the water and precipitated solid. This is attributed to kinetic effects during CaCO 3 deposited from a highly supersaturated solution, in which precipitation is faster than equilibration with respect to isotopes. Plant populations in the water have virtually no influence on CO 2 degassing, calcite saturation and isotopic fractionation. Measurements of Psub(CO 2 ), Ssub(C) and 13 C within a diurnal cycle demonstrate that metabolic effects are below the detection limit in a system with a high supply-rate of dissolved carbonate species. The observed variations are due to differences in CO 2 degassing and calcite precipitation, caused by a continuously changing hydrodynamic conditions and carbonate nucleation rates. (Auth.)

  18. Oxygen isotope geochemistry of The Geysers reservoir rocks, California

    Energy Technology Data Exchange (ETDEWEB)

    Gunderson, Richard P.; Moore, Joseph N.

    1994-01-20

    Whole-rock oxygen isotopic compositions of Late Mesozoic graywacke, the dominant host rock at The Geysers, record evidence of a large liquid-dominated hydrothermal system that extended beyond the limits of the present steam reservoir. The graywackes show vertical and lateral isotopic variations that resulted from gradients in temperature, permeability, and fluid composition during this early liquid-dominated system. All of these effects are interpreted to have resulted from the emplacement of the granitic "felsite" intrusion 1-2 million years ago. The {delta}{sup 18}O values of the graywacke are strongly zoned around a northwest-southeast trending low located near the center of and similar in shape to the present steam system. Vertical isotopic gradients show a close relationship to the felsite intrusion. The {delta}{sup 18}O values of the graywacke decrease from approximately 15 per mil near the surface to 4-7 per mil 300 to 600 m above the intrusive contact. The {delta}{sup 18}O values then increase downward to 8-10 per mil at the felsite contact, thereafter remaining nearly constant within the intrusion itself. The large downward decrease in {delta}{sup 18}O values are interpreted to be controlled by variations in temperature during the intrusive event, ranging from 150{degree}C near the surface to about 425{degree}C near the intrusive contact. The upswing in {delta}{sup 18}O values near the intrusive contact appears to have been caused by lower rock permeability and/or heavier fluid isotopic composition there. Lateral variations in the isotopic distributions suggests that the effects of temperature were further modified by variations in rock permeability and/or fluid-isotopic composition. Time-integrated water:rock ratios are thought to have been highest within the central isotopic low where the greatest isotopic depletions are observed. We suggest that this region of the field was an area of high permeability within the main upflow zone of the liquid

  19. (18)O(2) label mechanism of sulfur generation and characterization in properties over mesoporous Sm-based sorbents for hot coal gas desulfurization.

    Science.gov (United States)

    Liu, B S; Wan, Z Y; Wang, F; Zhan, Y P; Tian, M; Cheung, A S C

    2014-02-28

    Using a sol-gel method, SmMeOx/MCM-41 or SBA-15 (Me=Fe, Co and Zn) and corresponding unsupported sorbents were prepared. The desulfurization performance of these sorbents was evaluated over a fixed-bed reactor and the effects of reaction temperature, feed and sorbent composition on desulfurization performance were studied. Samarium-based sorbents used to remove H2S from hot coal gas were reported for the first time. The results of successive sulfidation/regeneration cycles revealed that SmFeO3/SBA-15 sorbent was suitable for desulfurization of hot coal gas in the chemical industry. The formation of elemental sulfur during both sulfidation and regeneration processes depended strongly on the catalytic action of Sm2O2S species, which was confirmed for the first time via high sensitive time of flight mass spectrometer (TOF-MS) using 6%vol(18)O2/Ar regeneration gas and can reduce markedly procedural complexity. The sorbents were characterized using N2-adsorption, high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), temperature-programmed reduction of H2 (H2-TPR), thermogravimetry (TG) and time-of-flight mass spectrometry (TOF-MS) techniques. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. High-precision 13C and 18O measurements by continuous flow-isotope ratio mass spectrometry (CF-IRMS) in Romanian wines characterization

    International Nuclear Information System (INIS)

    Costinel, Diana; Ionete, Roxana; Vremera, Raluca; Stanciu, Vasile

    2008-01-01

    Wines characterization is an important problem to which isotopic analysis by continuous flow- IRMS has made a significant contribution. The use of mass spectrometry (MS) to determine the ratios of stable isotopes in bio-molecules now provides the means to prove the botanical and geographical origin of a wide variety of foodstuffs - and therefore, to authenticate and eliminate fraud. There is a strong need for reliable and validated methods to ensure compliance with such regulation and to protect the interests of the consumer. The right to producing wines with an appellation of origin is guaranteed by the Ministry of Agriculture, based on proposals made by the National Office of Vine and Wine (starting with the 1993 vintage year). The Ministry of Agriculture, the National Office for Vine and Wine, and the National Research Institute grants the authentication of the wines with appellation of origin. The present paper emphasize the isotopic analysis for 18 O/ 16 O and 13 C/ 12 C from wines, using a new generation Isotope Ratio MS, CF-IRMS Delta V Plus, coupled with three flexible continuous flow preparation devices (GasBench II and TC Elemental Analyser). (authors)

  1. Understanding the groundwater dynamics in the Southern Rift Valley Lakes Basin (Ethiopia). Multivariate statistical analysis method, oxygen (δ 18O) and deuterium (δ 2H)

    International Nuclear Information System (INIS)

    Girum Admasu Nadew; Zebene Lakew Tefera

    2013-01-01

    Multivariate statistical analysis is very important to classify waters of different hydrochemical groups. Statistical techniques, such as cluster analysis, can provide a powerful tool for analyzing water chemistry data. This method is used to test water quality data and determine if samples can be grouped into distinct populations that may be significant in the geologic context, as well as from a statistical point of view. Multivariate statistical analysis method is applied to the geochemical data in combination with δ 18 O and δ 2 H isotopes with the objective to understand the dynamics of groundwater using hierarchical clustering and isotope analyses. The geochemical and isotope data of the central and southern rift valley lakes have been collected and analyzed from different works. Isotope analysis shows that most springs and boreholes are recharged by July and August rainfalls. The different hydrochemical groups that resulted from the multivariate analysis are described and correlated with the geology of the area and whether it has any interaction with a system or not. (author)

  2. Raman spectra of Nd/Sn cosubstituted Ba6-3xSm8+2xTi18O54 microwave dielectric ceramics

    Science.gov (United States)

    Wu, S. Y.; Li, Y.; Chen, X. M.

    2004-11-01

    The Raman spectra and dielectric properties of Nd /Sn cosubstituted Ba6-3xSm8+2xTi18O54 (x =2/3) microwave dielectric ceramics were discussed as the functions of composition and sintering time. The peaks in 753cm-1 were caused by the second order scatter. The peaks in 425 and 403cm-1 became sharper with prolonging sintering time, and this reflected the increased lattice defects. The shoulder peak near 292cm-1 was caused by the octahedral tilt when A site is Nd3+. The Raman shifts in 590, 520, 280, and 232cm-1 indicated no obvious change in position, but all peaks became sharper with prolonging sintering time. This indicated the increased ordering degree of A-site cations. With prolonging sintering time, the Qf factor (Q is the inverse of dielectric loss, tan δ, and f is the resonant frequency) increased, and the temperature coefficient of resonant frequency significantly decreased or became more negative, while the dielectric constant indicated no significant variation.

  3. Using Halogens (Cl, Br, F, I) and Stable Isotopes of Water (δ18O, δ2H) to Trace Hydrological and Biogeochemical Processes in Prairie Wetlands

    Science.gov (United States)

    Levy, Z. F.; Lu, Z.; Mills, C. T.; Goldhaber, M. B.; Rosenberry, D. O.; Mushet, D.; Siegel, D. I.; Fiorentino, A. J., II; Gade, M.; Spradlin, J.

    2014-12-01

    Prairie pothole wetlands are ubiquitous features of the Great Plains of North America, and important habitat for amphibians and migratory birds. The salinity of proximal wetlands varies highly due to groundwater-glacial till interactions, which influence wetland biota and associated ecosystem functions. Here we use halogens and stable isotopes of water to fingerprint hydrological and biogeochemical controls on salt cycling in a prairie wetland complex. We surveyed surface, well, and pore waters from a groundwater recharge wetland (T8) and more saline closed (P1) and open (P8) basin discharge wetlands in the Cottonwood Lake Study Area (ND) in August/October 2013 and May 2014. Halogen concentrations varied over a broad range throughout the study area (Cl = 2.2 to 170 mg/L, Br = 13 to 2000 μg/L, F = evaporation-enriched pond water (δ18O = -9.5 to -2.71 ‰) mixes with shallow groundwater in the top 0.6 m of fringing wetland soils and 1.2 m of the substrate in the center of P1. Our results suggest endogenous sources for Br and I within the prairie landscape that may be controlled by biological mechanisms or weathering of shale from glacial till.

  4. Validation of the doubly-labeled water (H3H18O) method for measuring water flux and energy metabolism in tenebrionid beetles

    International Nuclear Information System (INIS)

    Cooper, P.D.

    1981-01-01

    Doubly-labeled water (H 3 H 18 O) has been used to determine water flux and energy metabolism in a variety of vertebrates. This study examines the applicability of this technique to arthropods. The theory of the technique depends upon the assumption that doubly-labeled water introduced into the animal's body water equilibrates with water and carbon dioxide by the action of carbonic anhydrase. Tritium ( 3 H) is lost from the animal only with water while oxygen-18 is lost with both water and carbon dioxide. The difference bwtween the rates of loss of the two isotopes is proportional to CO 2 loss rate. Validation of the use of tritiated water for measuring water flux was accomplished by comparing gravimetric measurements of water gain with flux rates determined by loss of tritiated water. At room humidity, an overestimate for influx calculated from labeled water calculations was found, averaging 12 mg H 2 O (g.d) -1 . Comparison of CO 2 loss rate determined isotopically with rates of CO 2 loss determined by standard metabolic rates also yielded overestimates for the isotopic technique, overestimates ranging between 20 and 30%. The relevance of this for studies using labeled water for studying water fluxes and free metabolism of free-ranging arthropods is discussed

  5. Zoning Of Pollutant Dispersion Came From IJEN Crater In The Downstream Region Of BANYUPUTIH River Using Oxygen-18 (18O) Natural Isotope Technique

    International Nuclear Information System (INIS)

    Susiati, Heni; Yarianto, S.B.S.; Sjarmufni, A.; Suprijadi; Wibagyo

    2002-01-01

    The research should be arranged for natural isotope composition of Oxygen-18 ( 18 O) in the water catchments of Banyupahit -Banyuputih river. Aim of the research are determine zoning of pollutant dispersion and be clarified that the pollution really come from lien crater as more surely above mentioned by the result of investigation previously. Research method be used field survey and characteristic analysis of Oksigen-18 isotope. Zoning of pollutant dispersion in the downstream side covers settlement. agricultural, plantation, and sugar factory area have conducted by analyzing Oksigen-18 isotope characteristic. Based on the result of the research pollutant dispersion area in the downstream region. the Eastern side of water catchments area were categorized as pollution level l was more dominant rather than in the Western side and pollution level II came from water pound area of Banyuputih. This phenomena caused of an irrigation system using by Liwung Water Pound of Banyuputih river which should be polluted by Sulfur. Geological factor in the Eastern (lithology) were most of sand rock also induce the dispersion of Sulfur rather than in the Western area. Present research has clarified previous investigation that Banyupahit river were polluted by Sulfur as a result of ijen crater leakage

  6. The Value of Value

    DEFF Research Database (Denmark)

    Sørensen, Asger

    parts of business ethics given prominence to especially one term, namely `value'. The question that interests me is the following: What does the articulation of ethics and morality in terms of values mean for ethics and morality as such. Or, to put the question in a more fashionably way: What......As a social scientist of ethics and morality, Luhmann has noticed the ethical wave that has recently swept across the western world, and states that this particular kind of wave seems to have a wavelength of about one hundred years (cf. Luhmann 1989: 9 ff.). Even though the frequency...... and the regularity of such a phenomenon is both hard to verify and, if true, difficult to explain, it seems fair to say that since the Enlightenment, an approaching fin-de-siecle has brought an increased interest in matters concerning morality and ethics.1 The present peak has in public-political discourse and some...

  7. Method for selective recovery of PET-usable quantities of [.sup.18 F] fluoride and [.sup.13 N] nitrate/nitrite from a single irradiation of low-enriched [.sup.18 O] water

    Science.gov (United States)

    Ferrieri, Richard A.; Schlyer, David J.; Shea, Colleen

    1995-06-13

    A process for simultaneously producing PET-usable quantities of [.sup.13 N]NH.sub.3 and [.sup.18 F]F.sup.- for radiotracer synthesis is disclosed. The process includes producing [.sup.13 N]NO.sub.2.sup.- /NO.sub.3.sup.- and [.sup.18 F]F.sup.- simultaneously by exposing a low-enriched (20%-30%) [.sup.18 O]H.sub.2 O target to proton irradiation, sequentially isolating the [.sup.13 N]NO.sub.2.sup.- /NO.sub.3.sup.- and [.sup.18 F]F.sup.- from the [.sup.18 O]H.sub.2 O target, and reducing the [.sup.13 N]NO.sub.2.sup.- /NO.sub.3.sup.- to [.sup.13 N]NH.sub.3. The [.sup.13 N]NH.sub.3 and [.sup.18 F]F.sup.- products are then conveyed to a laboratory for radiotracer applications. The process employs an anion exchange resin for isolation of the isotopes from the [.sup.18 O]H.sub.2 O, and sequential elution of [.sup.13 N]NO.sub.2.sup.- /NO.sub.3.sup.- and [ .sup.18 F]F.sup.- fractions. Also the apparatus is disclosed for simultaneously producing PET-usable quantities of [.sup.13 N]NH.sub.3 and [.sup.18 F]F.sup.- from a single irradiation of a single low-enriched [.sup.18 O]H.sub.2 O target.

  8. Improved Charge Transfer in a Mn2O3@Co1.2Ni1.8O4 Hybrid for Highly Stable Alkaline Direct Methanol Fuel Cells with Good Methanol Tolerance.

    Science.gov (United States)

    Liu, Yan; Chen, Yuanzhen; Li, Sai; Shu, Chenyong; Fang, Yuan; Song, Bo

    2018-03-21

    A three-dimensional Mn 2 O 3 @Co 1.2 Ni 1.8 O 4 hybrid was synthesized via facile two-step processes and employed as a cathode catalyst in direct methanol fuel cells (DMFCs) for the first time. Because of the unique architecture with ultrathin and porous nanosheets of the Co 1.2 Ni 1.8 O 4 shell, this composite exhibits better electrochemical performance than the pristine Mn 2 O 3 . Remarkably, it shows excellent methanol tolerance, even in a high concentration solution. The DMFC was assembled with Mn 2 O 3 @Co 1.2 Ni 1.8 O 4 , polymer fiber membranes, and PtRu/C as the cathode, membrane, and anode, respectively. The power densities of 57.5 and 70.5 mW cm -2 were recorded at 18 and 28 °C, respectively, especially the former is the best result reported in the literature at such a low temperature. The stability of the Mn 2 O 3 @Co 1.2 Ni 1.8 O 4 catalyzed cathode was evaluated, and the results show that this compound possesses excellent stability in a high methanol concentration. The improved electrochemical activity could be attributed to the narrow band gap of the hybrid, which accelerates the electrons jumping from the valence band to the conduction band. Therefore, Mn III could be oxidized into Mn IV more easily, simultaneously providing an electron to the absorbed oxygen.

  9. Test and implementation of position sensors on load and unload [18O]H2O control valve of the target used in 18F - production by proton irradiation

    International Nuclear Information System (INIS)

    Costa, Osvaldo L. da; Sciani, Valdir

    2009-01-01

    The radionuclide 18 F used to produce the radiopharmaceutical [ 18 F]FDG has 109.7 min of half-life, becoming your productive chain so peculiar, because since the beginning of [ 18 O]H 2 O irradiation until the PET-CT exam there is a period about six hours, and any procedure fail in the productive chain will result in a delay to the PET CT exam. The absence of the position signs from [ 18 O]H 2 O load and unload valve of the target may result in 18 F production loss and even area contamination around the target. In this paper, three types of position sensors, into cyclotron radionuclides production environment in Cyclotron Accelerator Center from IPEN-CNEN/SP were tested. The tests were an indicative to discover the fitter sensor to the [ 18 O]H 2 O load and unload valve from target used in [ 18 F]fluoride production. After finding the fitter sensor, it was implemented in 18 F- target, supplying the correct position from [ 18 O]H 2 O load and unload valve to programmable logic controller, that had the software modified, respecting in this way the valve position. By this way, it was possible to reduce the incidence of fails, increasing the reliability in [ 18 F]FDG productive chain. (author)

  10. The Trojan Horse Method as a tool to investigate low-energy resonances: the 18O(p, α)15N and 17O(p, α)14N cases

    International Nuclear Information System (INIS)

    La Cognata, M.; Sergi, M. L.; Spitaleri, C.; Cherubini, S.; Gulino, M.; Kiss, G.; Lamia, L.; Pizzone, R. G.; Romano, S.; Mukhamedzhanov, A.; Goldberg, V.; Tribble, R.; Coc, A.; Hammache, F.; Sereville, N. de; Irgaziev, B.; Tumino, A.

    2010-01-01

    The 18 O(p, α) 15 N and 17 O(p, α) 14 N reactions are of primary importance in several as-trophysical scenarios, including nucleosynthesis inside Asymptotic Giant Branch stars and oxygen and nitrogen isotopic ratios in meteorite grains. They are also key reactions to understand exotic systems such as R-Coronae Borealis stars and novae. Thus, the measurement of their cross sections in the low energy region can be crucial to reduce the nuclear uncertainty on theoretical predictions, because the resonance parameters are poorly determined. The Trojan Horse Method, in its newly developed form particularly suited to investigate low-energy resonances, has been applied to the 2 H( 18 O, α 15 N)n and 2 H( 17 O, α 14 N)n reactions to deduce the 18 O(p, α) 15 N and 17 O(p, α) 14 N cross sections at low energies. Resonances in the 18 O(p, α) 15 N and 17 O(p, α) 14 N excitation functions have been studied and the resonance parameters deduced.

  11. Hot and cold CO{sub 2}-rich mineral waters in Chaves geothermal area (northern Portugal)

    Energy Technology Data Exchange (ETDEWEB)

    Aires-Barros, Luis; Marques, Jose Manuel; Graca, Rui Cores; Matias, Maria Jose [Universidade Tecnica de Lisboa, Lab. de Mineralogia e Petrologia (LAMPIST), Lisboa (Portugal); Weijden, Cornelis H. van der; Kreulen, Rob [Utrecht Univ., Dept. of Geochemistry, Utrecht (Netherlands); Eggenkamp, Hermanus Gerardus M. [Utrecht Univ., Dept. of Geochemistry, Utrecht (Netherlands); Reading Univ., Postgraduate Research Inst. for Sedimentology, Reading (United Kingdom)

    1998-02-01

    In order to update the geohydrologic characterisation of Chaves geothermal area, coupled isotopic and chemical studies have been carried out on hot and cold CO{sub 2}-rich mineral waters discharging, in northern Portugal, along one of the major regional NNE-trending faults (the so-called Verin-Chaves-Penacova D