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Sample records for carbon stable isotope

  1. Stable-carbon isotope variability in tree foliage and wood

    International Nuclear Information System (INIS)

    Leavitt, S.W.; Long, A.

    1986-01-01

    This study documents variation of stable-carbon isotope ratios ( 13 C/ 12 C) in trees of genera Juniperus and Pinus under field conditions. Results are from cellulose analysis on leaves, twigs, and wood from a number of localities in the southwestern US. Substantial variability, typically 1-3%, exists among leaves, within wood (radially, vertically, circumferentially), and between individuals at a site. These results may help guide sampling in tracer-type studies with stable-carbon isotope ratios and aid in the interpretation of isotopic results from such studies

  2. Stable carbon isotope biogeochemistry of lakes along a trophic gradient

    NARCIS (Netherlands)

    de Kluijver, A.; Schoon, P.L.; Downing, J.A.; Schouten, S.; Middelburg, J.J.

    2014-01-01

    The stable carbon (C) isotope variability of dissolved inorganic and organic C (DIC and DOC), particulate organic carbon (POC), glucose and polar-lipid derived fatty acids (PLFAs) was studied in a survey of 22 North American oligotrophic to eutrophic lakes. The d13C of different PLFAs were used as

  3. Biosynthetic effects on the stable carbon isotopic compositions of agal lipids: Implications for deciphering the carbon isotopic biomarker record

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Schouten, S.; Klein Breteler, W.C.M.; Blokker, P.; Schogt, N.; Rijpstra, W.I.C.; Grice, K.; Baas, M.

    1998-01-01

    Thirteen species of algae covering an extensive range of classes were cultured and stable carbon isotopic compositions of their lipids were analysed in order to assess carbon isotopic fractionation effects during their biosynthesis. The fatty acids were found to have similar stable carbon isotopic

  4. Stable isotope compositions of organic carbon and contents of ...

    African Journals Online (AJOL)

    The stable isotope compositions of organic carbon (OC), and contents of OC and nitrogen for four sediment cores recovered from lakes Makat (located in the Ngorongoro Crater), Ndutu and Masek (located in the Serengeti Plains) are used to document sources of organic matter (OM) and climatic changes in sub-arid ...

  5. Characteristics of stable carbon isotopic composition of shale gas

    Directory of Open Access Journals (Sweden)

    Zhenya Qu

    2016-04-01

    Full Text Available A type Ⅱ kerogen with low thermal maturity was adopted to perform hydrocarbon generation pyrolysis experiments in a vacuum (Micro-Scale Sealed Vessel system at the heating rates of 2 °C/h and 20 °C/h. The stable carbon isotopic compositions of gas hydrocarbons were measured to investigate their evolving characteristics and the possible reasons for isotope reversal. The δ13C values of methane became more negative with the increasing pyrolysis temperatures until it reached the lightest point, after which they became more positive. Meanwhile, the δ13C values of ethane and propane showed a positive trend with elevating pyrolysis temperatures. The carbon isotopic compositions of shale gasses were mainly determined by the type of parent organic matter, thermal evolutionary extent, and gas migration in shale systems. Our experiments and study proved that the isotope reversal shouldn't occur in a pure thermogenic gas reservoir, it must be involved with some other geochemical process/es; although mechanisms responsible for the reversal are still vague. Carbon isotopic composition of the Fayetteville and Barnett shale gas demonstrated that the isotope reversal was likely involved with water–gas reaction and Fischer-Tropsch synthesis during its generation.

  6. Stable isotopes

    International Nuclear Information System (INIS)

    Evans, D.K.

    1986-01-01

    Seventy-five percent of the world's stable isotope supply comes from one producer, Oak Ridge Nuclear Laboratory (ORNL) in the US. Canadian concern is that foreign needs will be met only after domestic needs, thus creating a shortage of stable isotopes in Canada. This article describes the present situation in Canada (availability and cost) of stable isotopes, the isotope enrichment techniques, and related research programs at Chalk River Nuclear Laboratories (CRNL)

  7. Patterns in Stable Isotope Values of Nitrogen and Carbon in ...

    Science.gov (United States)

    Stable isotope measurements of nitrogen and carbon (15N, 13ddC) are often used to characterize estuarine, nearshore, and open ocean ecosystems. Reliable information about the spatial distribution of base-level stable isotope values, often represented by primary producers, is critical to interpreting values in these ecosystems. While base-level isotope data are generally readily available for estuaries, nearshore coastal waters, and the open ocean, the continental shelf is less studied. To address this, and as a first step toward developing a surrogate for base-level isotopic signature in this region, we collected surface and deep water samples from the United States’ eastern continental shelf in the Western Atlantic Ocean, from the Gulf of Maine to Cape Hatteras, periodically between 2000 and 2013. During the study, particulate matter 15dN values ranged from 0.8 to 17.4‰, and 13dC values from −26.4 to −15.6‰over the region. We used spatial autocorrelation analysis and random forest modeling to examine the spatial trends and potential environmental drivers of the stable isotope values. We observed general trends toward lower values for both nitrogen and carbon isotopes at the seaward edge of the shelf. Conversely, higher 15dN and 13dC values were observed on the landward edge of the shelf, in particular in the southern portion of the sampling area. Across all sites, the magnitude of the difference between the 15dN of subsurface and surface particulate m

  8. Culture of microalgae Spirulina platensis with isotope stable Carbon-13

    International Nuclear Information System (INIS)

    Cronemberger, Luiz C.A.; Costa, Vladimir E.

    2017-01-01

    Gastric emptying time abnormalities cause complications that affect the quality of life in humans and scintigraphy is the gold standard for this diagnosis. However its application has restrictions due to the use of the radiopharmaceutical 99m Tc. An alternative to this method is the stable carbon isotope respiratory test. This is a non-radioactive, noninvasive technique with no contraindications. Its application varies according to the substrate used. For evaluation of gastric emptying time one of the substrates that can be used in the respiratory test is Spirulina platensis labeled at 97% carbon atoms with the stable isotope carbon-13 ( 13 C). In Brazil, there is no production of this substrate and its high cost (US$475.00/g, excluding import taxes) makes it difficult to apply the test. Thus, the objective of the work is to cultivate labeled S. platensis at 97% of 13 C for use in the respiratory test for gastric emptying and to establish optimization parameters for the best cost-benefit of this culture. In the cultivation process the microalgae will be kept in a closed sterilized glass volumetric flask, with deionized water and a pure 13 C source. The light (photoperiod 12h light / dark), pH (∼ 9.5) and temperature (30 deg C) will be controlled and after 35-40 days of growth, the cyanobacteria will be lyophilized and ground for the acquisition of a powder that will be analyzed by IRMS and compared to S. platensis, which will be our reference standard

  9. Stable isotope composition of atmospheric carbon monoxide. A modelling study

    International Nuclear Information System (INIS)

    Gromov, Sergey S.

    2014-01-01

    This study aims at an improved understanding of the stable carbon and oxygen isotope composition of the carbon monoxide (CO) in the global atmosphere by means of numerical simulations. At first, a new kinetic chemistry tagging technique for the most complete parameterisation of isotope effects has been introduced into the Modular Earth Submodel System (MESSy) framework. Incorporated into the ECHAM/MESSy Atmospheric Chemistry (EMAC) general circulation model, an explicit treatment of the isotope effects on the global scale is now possible. The expanded model system has been applied to simulate the chemical system containing up to five isotopologues of all carbon- and oxygen-bearing species, which ultimately determine the δ 13 C, δ 18 O and Δ 17 O isotopic signatures of atmospheric CO. As model input, a new stable isotope-inclusive emission inventory for the relevant trace gases has been compiled. The uncertainties of the emission estimates and of the resulting simulated mixing and isotope ratios have been analysed. The simulated CO mixing and stable isotope ratios have been compared to in-situ measurements from ground-based observatories and from the civil-aircraft-mounted CARIBIC-1 measurement platform. The systematically underestimated 13 CO/ 12 CO ratios of earlier, simplified modelling studies can now be partly explained. The EMAC simulations do not support the inferences of those studies, which suggest for CO a reduced input of the highly depleted in 13 C methane oxidation source. In particular, a high average yield of 0.94 CO per reacted methane (CH 4 ) molecule is simulated in the troposphere, to a large extent due to the competition between the deposition and convective transport processes affecting the CH 4 to CO reaction chain intermediates. None of the other factors, assumed or disregarded in previous studies, however hypothesised to have the potential in enriching tropospheric CO in 13 C, were found significant when explicitly simulated. The

  10. Stable isotopes

    International Nuclear Information System (INIS)

    Brazier, J.L.; Guinamant, J.L.

    1995-01-01

    According to the progress which has been realised in the technology of separating and measuring isotopes, the stable isotopes are used as preferable 'labelling elements' for big number of applications. The isotopic composition of natural products shows significant variations as a result of different reasons like the climate, the seasons, or their geographic origins. So, it was proved that the same product has a different isotopic composition of alimentary and agriculture products. It is also important in detecting the pharmacological and medical chemicals. This review article deals with the technology, like chromatography and spectrophotometry, adapted to this aim, and some important applications. 17 refs. 6 figs

  11. Stable carbon isotope response to oceanic anoxic events

    International Nuclear Information System (INIS)

    Hu Xiumian; Wang Chengshan; Li Xianghui

    2001-01-01

    Based on discussion of isotope compositions and fractionation of marine carbonate and organic carbon, the author studies the relationship between oceanic anoxic events and changes in the carbon isotope fractionation of both carbonate and organic matter. During the oceanic anoxic events, a great number of organisms were rapidly buried, which caused a kind of anoxic conditions by their decomposition consuming dissolved oxygen. Since 12 C-rich organism preserved, atmosphere-ocean system will enrich relatively of 13 C. As a result, simultaneous marine carbonate will record the positive excursion of carbon isotope. There is a distinctive δ 13 C excursion during oceanic anoxic events in the world throughout the geological time. In the Cenomanian-Turonian anoxic event. this positive excursion arrived at ∼0.2% of marine carbonate and at ∼0.4% of organic matter, respectively. Variations in the carbon isotopic compositions of marine carbonate and organic carbon record the changes in the fraction of organic carbon buried throughout the geological time and may provide clues to the changes in rates of weathering and burial of organic carbon. This will provide a possibility of interpreting not only the changes in the global carbon cycle throughout the geological time, but also that in atmospheric p CO 2

  12. Tracing organic matter sources of estuarine tidal flat nematodes with stable carbon isotopes

    NARCIS (Netherlands)

    Moens, T.; Luyten, C.; Middelburg, J.J.; Herman, P.M.J.; Vincx, M.

    2002-01-01

    The present study explores the use of stable carbon isotopes to trace organic matter sources of intertidal nematodes in the Schelde estuary (SW Netherlands). Stable carbon isotope signatures of nematodes from a saltmarsh and 4 tidal flat stations were determined in spring and winter situations, and

  13. Stable isotope analysis of Dacryoconarid carbonate microfossils: a new tool for Devonian oxygen and carbon isotope stratigraphy.

    Science.gov (United States)

    Frappier, Amy Benoit; Lindemann, Richard H; Frappier, Brian R

    2015-04-30

    Dacryoconarids are extinct marine zooplankton known from abundant, globally distributed calcite microfossils in the Devonian, but their shell stable isotope composition has not been previously explored. Devonian stable isotope stratigraphy is currently limited to less common invertebrates or bulk rock analyses of uncertain provenance. As with Cenozoic planktonic foraminifera, isotopic analysis of dacryoconarid shells could facilitate higher-resolution, geographically widespread stable isotope records of paleoenvironmental change, including marine hypoxia events, climate changes, and biocrises. We explored the use of Dacryoconarid isotope stratigraphy as a viable method in interpreting paleoenvironments. We applied an established method for determining stable isotope ratios (δ(13) C, δ(18) O values) of small carbonate microfossils to very well-preserved dacryoconarid shells. We analyzed individual calcite shells representing five common genera using a Kiel carbonate device coupled to a MAT 253 isotope ratio mass spectrometer. Calcite shell δ(13) C and δ(18) O values were compared by taxonomic group, rock unit, and locality. Single dacryoconarid calcite shells are suitable for stable isotope analysis using a Kiel-IRMS setup. The dacryoconarid shell δ(13) C values (-4.7 to 2.3‰) and δ(18) O values (-10.3 to -4.8‰) were consistent across taxa, independent of shell size or part, but varied systematically through time. Lower fossil δ(18) O values were associated with warmer water temperature and more variable δ(13) C values were associated with major bioevents. Dacryoconarid δ(13) C and δ(18) O values differed from bulk rock carbonate values. Dacryoconarid individual microfossil δ(13) C and δ(18) O values are highly sensitive to paleoenvironmental changes, thus providing a promising avenue for stable isotope chemostratigraphy to better resolve regional to global paleoceanographic changes throughout the upper Silurian to the upper Devonian. Our results

  14. Elemental and stable isotopic approaches for studying the organic and inorganic carbon components in natural samples

    International Nuclear Information System (INIS)

    Helie, J-F

    2009-01-01

    The carbon cycle is an important part of major biogeochemical cycles. Many techniques may be used to characterize carbon amounts and sources in the environment. Here we first review the most popular techniques for the determination of organic and inorganic carbon concentrations. Decarbonatation techniques are also reviewed in details since it is often an important part of organic carbon analysis. The second part of this paper addresses the use of carbon stable isotopes to characterize organic carbon sources and processes in the environment. An overview of general stable isotopes background and terminology is given as well as the most popular analytical techniques.

  15. The use of carbon stable isotope ratios in drugs characterization

    Energy Technology Data Exchange (ETDEWEB)

    Magdas, D. A., E-mail: gabriela.cristea@itim-cj.ro; Cristea, G., E-mail: gabriela.cristea@itim-cj.ro; Bot, A., E-mail: gabriela.cristea@itim-cj.ro; Mirel, V., E-mail: gabriela.cristea@itim-cj.ro [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath Str., 400293 Cluj-Napoca (Romania)

    2013-11-13

    Isotopic Ratio Mass Spectrometry (IRMS) is an effective toll to be used for drug product authentication. The isotopic composition could be used to assist in the differentiation between batches of drugs and assist in the identification of counterfeit materials on the market. Only two factors affect the isotopic ratios in pharmaceutical components: the isotopic composition of the raw materials and the synthetic processes performed upon them. Counterfeiting of pharmaceutical drugs threatens consumer confidence in drug products companies' economical well-being. In this preliminary study, the analyzed samples consist in two types of commercially available analgesics, which were purchases from Romanian pharmacies. Differences in δ{sup 13}C between batches from −29.7 to −31.6% were observed, demonstrating that this method can be used to differentiate among individual drug batches and subsequently identify counterfeits on the market. On the other hand, carbon isotopic ratios differences among producers were recorded, the variations being between −31.3 to −34.9% for the same type of analgesic, but from different manufactures.

  16. LBA-ECO CD-02 Carbon, Nitrogen, Oxygen Stable Isotopes in Organic Material, Brazil

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set reports the measurement of stable carbon, nitrogen, and oxygen isotope ratios in organic material (plant, litter and soil samples) in forest canopy...

  17. LBA-ECO CD-02 Carbon, Nitrogen, Oxygen Stable Isotopes in Organic Material, Brazil

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set reports the measurement of stable carbon, nitrogen, and oxygen isotope ratios in organic material (plant, litter and soil samples) in forest...

  18. Stable carbon, nitrogen and sulfur isotopes in non-carbonate fractions of cold-seep carbonates

    Science.gov (United States)

    Feng, Dong; Peng, Yongbo; Peckmann, Jörn; Roberts, Harry; Chen, Duofu

    2017-04-01

    Sulfate-driven anaerobic oxidation of methane (AOM) supports chemosynthesis-based communities and limits the release of methane from marine sediments. This process promotes the formation of carbonates close to the seafloor along continental margins. The geochemical characteristics of the carbonate minerals of these rocks are increasingly understood, questions remain about the geochemical characteristics of the non-carbonate fractions. Here, we report stable carbon, nitrogen and sulfur isotope patterns in non-carbonate fractions of seep carbonates. The authigenic carbonates were collected from three modern seep provinces (Black Sea, Gulf of Mexico, and South China Sea) and three ancient seep deposits (Marmorito, northern Italy, Miocene; SR4 deposit of the Lincoln Creek Formation and Whiskey Creek, western Washington, USA, Eocene to Oligocene). The δ13C values of non-carbonate fractions range from ˜-25‰ to -80‰ VPDB. These values indicate that fossil methane mixed with varying amounts of pelagic organic matter is the dominant source of carbon in these fractions. The relatively small offset between the δ34S signatures of the non-carbonate fractions and the respective sulfide minerals suggests that locally produced hydrogen sulfide is the main source of sulfur in seep environments. The δ15N values of the non-carbonate fractions are generally lower than the corresponding values of deep-sea sediments, suggesting that organic nitrogen is mostly of a local origin. This study reveals the potential of using δ13C, δ15N, δ34S values to discern seep and non-seep deposits. In cases where δ13Ccarbonate values are only moderately low due to mixing processes and lipid biomarkers have been erased in the course of burial, it is difficult to trace back AOM owing to the lack of other records. This problem is even more pronounced when authigenic carbonate is not available in ancient seep environments. Acknowledgments: The authors thank BOEM and NOAA for their years' support

  19. Methodologies for extraction of dissolved inorganic carbon for stable carbon isotope studies : evaluation and alternatives

    Science.gov (United States)

    Hassan, Afifa Afifi

    1982-01-01

    The gas evolution and the strontium carbonate precipitation techniques to extract dissolved inorganic carbon (DIC) for stable carbon isotope analysis were investigated. Theoretical considerations, involving thermodynamic calculations and computer simulation pointed out several possible sources of error in delta carbon-13 measurements of the DIC and demonstrated the need for experimental evaluation of the magnitude of the error. An alternative analytical technique, equilibration with out-gassed vapor phase, is proposed. The experimental studies revealed that delta carbon-13 of the DIC extracted from a 0.01 molar NaHC03 solution by both techniques agreed within 0.1 per mil with the delta carbon-13 of the DIC extracted by the precipitation technique, and an increase of only 0.27 per mil in that extracted by the gas evolution technique. The efficiency of extraction of DIC decreased with sulfate concentration in the precipitation technique but was independent of sulfate concentration in the gas evolution technique. Both the precipitation and gas evolution technique were found to be satisfactory for extraction of DIC from different kinds of natural water for stable carbon isotope analysis, provided appropriate precautions are observed in handling the samples. For example, it was found that diffusion of atmospheric carbon dioxide does alter the delta carbon-13 of the samples contained in polyethylene bottles; filtration and drying in the air change the delta carbon-13 of the samples contained in polyethylene bottles; filtration and drying in the air change the delta carbon-13 of the precipitation technique; hot manganese dioxide purification changes the delta carbon-13 of carbon dioxide. (USGS)

  20. Changes of stable isotopes carbon-13 and nitrogen-15 in different tissues of cattle

    International Nuclear Information System (INIS)

    Sun Fengmei; Yu Hongxia; Wu Wei; Yang Shuming

    2009-01-01

    Stable isotope analysis is a potential tool for tracing food origin. The stable carbon and nitrogen isotope composition in different tissues of two varieties of cattle under the same culture condition were investigated. δ 13 C and δ 15 N values of different defatted muscle and crude fat, cattle tail hair, blood, liver and feed were determined by isotope ratio mass spectrometry, and statistical analysis was carried out. The results showed that stable isotopes of carbon and nitrogen composition was not affected by cattle variety; the δ 13 C values between different defatted muscle, blood, liver and cattle hair were not significantly different, but δ 15 N value in the liver was much higher than other muscle and the δ 13 C values didn't show difference among all the crude fat samples. So these results indicated that isotope fractionation in the various tissue was discrepant. (authors)

  1. The synthesis of a tritium, carbon-14, and stable isotope-labeled cathepsin C inhibitors.

    Science.gov (United States)

    Allen, Paul; Bragg, Ryan A; Caffrey, Moya; Ericsson, Cecilia; Hickey, Michael J; Kingston, Lee P; Elmore, Charles S

    2017-02-01

    As part of a medicinal chemistry program aimed at developing a highly potent and selective cathepsin C inhibitor, tritium, carbon-14, and stable isotope-labeled materials were required. The synthesis of tritium-labeled methanesulfonate 5 was achieved via catalytic tritiolysis of a chloro precursor, albeit at a low radiochemical purity of 67%. Tritium-labeled AZD5248 was prepared via a 3-stage synthesis, utilizing amide-directed hydrogen isotope exchange. Carbon-14 and stable isotope-labeled AZD5248 were successfully prepared through modifications of the medicinal chemistry synthetic route, enabling the use of available labeled intermediates. Copyright © 2016 John Wiley & Sons, Ltd.

  2. Stable isotopic constraints on global soil organic carbon turnover

    Science.gov (United States)

    Wang, Chao; Houlton, Benjamin Z.; Liu, Dongwei; Hou, Jianfeng; Cheng, Weixin; Bai, Edith

    2018-02-01

    Carbon dioxide release during soil organic carbon (SOC) turnover is a pivotal component of atmospheric CO2 concentrations and global climate change. However, reliably measuring SOC turnover rates on large spatial and temporal scales remains challenging. Here we use a natural carbon isotope approach, defined as beta (β), which was quantified from the δ13C of vegetation and soil reported in the literature (176 separate soil profiles), to examine large-scale controls of climate, soil physical properties and nutrients over patterns of SOC turnover across terrestrial biomes worldwide. We report a significant relationship between β and calculated soil C turnover rates (k), which were estimated by dividing soil heterotrophic respiration rates by SOC pools. ln( - β) exhibits a significant linear relationship with mean annual temperature, but a more complex polynomial relationship with mean annual precipitation, implying strong-feedbacks of SOC turnover to climate changes. Soil nitrogen (N) and clay content correlate strongly and positively with ln( - β), revealing the additional influence of nutrients and physical soil properties on SOC decomposition rates. Furthermore, a strong (R2 = 0.76; p turnover and thereby improving predictions of multiple global change influences over terrestrial C-climate feedback.

  3. Stable-carbon isotopic composition of maple sap and foliage

    International Nuclear Information System (INIS)

    Leavitt, S.W.; Long, A.

    1985-01-01

    The 13 C/ 12 C ratios of Acer grandidentatum sap sugar collected during the dormant period are compared to those of buds, leaves, and wood developed over the following growing season. As the primary carbon source for cellulose manufacture at initiation of annual growth in deciduous trees, sap sucrose would be expected to have an isotopic composition similar to first-formed cellulose. Although constancy in concentration and 13 C/ 12 C ratios of the maple sap sugar suggests any gains or losses (e.g. to maintenance metabolism) do not appreciably alter composition, the 13 C/ 12 C ratios of cellulose of the enlarging buds in the spring are quite distinct from those of the sap sugar, seemingly precluding a simple direct biochemical pathway of sap sucrose→glucose→cellulose in favor of a more complex pathway with greater likelihood of isotopic fractionation. The 13 C/ 12 C ratios of the leaves and in the growth ring were initially similar to the sap sugar but decreased steadily over the growing season. (author)

  4. Morphology, molecular structure, and stable carbon isotopic composition of black carbon (BC) in urban topsoils.

    Science.gov (United States)

    Zong, Yutong; Xiao, Qing; Lu, Shenggao

    2018-02-01

    Urban soils contain significant amounts of black carbon (BC) from biomass and fossil fuel combustion and regard to be a pool of BC. BC in urban soils has multiple effects on environmental processes in urban system, such as global climate change, air quality, and public health. Urban topsoil samples (0-10 cm) were collected from Anshan, Liaoning Province, northeast China, which is one of the most important old steel industrial bases in China. The BC in urban topsoils was extracted using the density method. Their chemical composition, morphology, molecular structure, and stable carbon isotopic composition were examined using elemental analysis, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and stable carbon isotope (δ 13 C). Elemental analysis shows that carbon content in the BC of studied soils ranged from 64.5 to 78.4%, with the average more than 70%. The O/C atomic ratio of BC is on average 0.18. The BC particle displays different morphology, including porous spherical, irregular porous fragmentary, and blocky shapes. The porous spherical BC particles has atomic molar O/C ratio determined by SEM-EDS ranging from 0.04 to 0.37. XRD indicates that BC exists in mainly combining with mineral phases hematite (Fe 2 O 3 ), kaolinite (Al 2 Si 2 O 5 (OH) 4 ), quartz (SiO 2 ), and calcite (CaCO 3 ). The FTIR spectra of BC particles show major bands at approximately 3400 cm -1 (O-H), 2920 cm -1 (C = H), 1600 cm -1 (C = C), 1230 cm -1 (C = O), and 1070 cm -1 (C = O). The stable carbon isotope (δ 13 C) of BC ranges from -24.48 to -23.18‰ with the average of -23.79 ± 0.39‰. The concentration of BC in the industrial area is significantly (p fuel combustion. Results indicated that a combination of atomic O/C ratio, porous structure, and stable carbon isotopic (δ 13 C) of BC could reflect effectively the origin of BC

  5. Distinguishing feral and managed honeybees (Apis mellifera) using stable carbon isotopes

    OpenAIRE

    Anderson , Lucy; Dynes , Travis; Berry , Jennifer; Delaplane , Keith; McCormick , Lydia; Brosi , Berry

    2014-01-01

    International audience; The ability to distinguish feral and managed honeybees (Apis mellifera) has applications in studies of population genetics, parasite transmission, pollination, interspecific interactions, and bee breeding. We evaluated a diagnostic test based on theoretical differences in stable carbon isotope ratios generated by supplemental feeding. We evaluated (1) if carbon isotope ratios can distinguish feral and managed honeybees and (2) the temporal persistence of the signal aft...

  6. Application of carbon and oxygen stable isotopes to the study of Brazilian precambrian

    International Nuclear Information System (INIS)

    Torquato, J.R.F.

    1980-01-01

    Samples of carbonated rocks of precambrian age are studied. The stable carbon and oxygen isotopes are applied to the study of terrestrial materials considering the variations of some element isotopic composition in function of the environment of sedimentation. The isotopic analysis was done using mass spectrometers. The analytical results and the description of region geology of the site of each sample are presented. The isotopic data are interpreted aiming to the environment of sedimentation. New techniques for better improvement of carbon and oxygen ratios, are proposed, such as: to use the analysis of surface trend and the isotopic logging in mapping of surface and subsurface. A new method for approximated determination of the ages of precambrian carbonated rocks, considering the limitations of their new technique, is also presented. (M.C.K.) [pt

  7. The carbon stable isotope biogeochemistry of streams, Taylor Valley, Antarctica

    International Nuclear Information System (INIS)

    Lyons, W.B.; Leslie, D.L.; Harmon, R.S.; Neumann, K.; Welch, K.A.; Bisson, K.M.; McKnight, D.M.

    2013-01-01

    Highlights: ► δ 13 C-DIC reported from McMurdo Dry Valleys, Antarctica, streams. ► Stream water δ 13 C PDB values range −9.4‰ to +5.1‰, largely inorganic in character. ► Atmospheric exchange is the dominant control on δ 13 C-DIC. - Abstract: The McMurdo Dry Valleys region of Antarctica is the largest ice-free region on the continent. This study reports the first C stable isotope measurements for dissolved inorganic C present in ephemeral streams in four dry valleys that flow for four to twelve weeks during the austral summer. One of these valleys, Taylor Valley, has been the focus of the McMurdo Dry Valleys Long-Term Ecological Research (MCM-LTER) program since 1993. Within Taylor Valley, numerous ephemeral streams deliver water to three perennially ice-covered, closed-basin lakes: Lake Fryxell, Lake Hoare, and Lake Bonney. The Onyx River in the Wright Valley, the longest river in Antarctica, flows for 40 km from the Wright Lower Glacier and Lake Brownworth at the foot of the glacier to Lake Vanda. Streamflow in the McMurdo Dry Valley streams is produced primarily from glacial melt, as there is no overland flow. However, hyporheic zone exchange can be a major hydrogeochemical process in these streams. Depending on landscape position, these streams vary in gradient, channel substrate, biomass abundance, and hyporheic zone extent. This study sampled streams from Taylor, Wright, Garwood, and Miers Valleys and conducted diurnal sampling of two streams of different character in Taylor Valley. In addition, transect sampling was undertaken of the Onyx River in Wright Valley. The δ 13 C PDB values from these streams span a range of greater than 14‰, from −9.4‰ to +5.1‰, with the majority of samples falling between −3‰ and +2‰, suggesting that the C stable isotope composition of dissolved C in McMurdo Dry Valley streams is largely inorganic in character. Because there are no vascular plants on this landscape and no groundwater input to these

  8. Grasland Stable Isotope Flux Measurements: Three Isotopomers of Carbon Dioxide Measured by QCL Spectroscopy

    Science.gov (United States)

    Zeeman, M. J.; Tuzson, B.; Eugster, W.; Werner, R. A.; Buchmann, N.; Emmenegger, L.

    2007-12-01

    To improve our understanding of greenhouse gas dynamics of managed ecosystems such as grasslands, we not only need to investigate the effects of management (e.g., grass cuts) and weather events (e.g., rainy days) on carbon dioxide fluxes, but also need to increase the time resolution of our measurements. Thus, for the first time, we assessed respiration and assimilation fluxes with high time resolution (5Hz) stable isotope measurements at an intensively managed farmland in Switzerland (Chamau, 400m ASL). Two different methods were used to quantify fluxes of carbon dioxide and associated fluxes of stable carbon isotopes: (1) the flux gradient method, and (2) the eddy covariance method. During a week long intensive measurement campaign, we (1) measured mixing ratios of carbon dioxide isotopomers (12C16O2, 12C16O18O, 13C16O2) with a Quantum Cascade Laser (QCL, Aerodyne Inc.) spectroscope and (2) collected air samples for isotope analyses (13C/12C) and (18O/16O) of carbon dioxide by Isotope Ratio Mass Spectrometry (IRMS, Finnigan) every two hours, concurrently along a height profile (z = 0.05; 0.10; 0.31; 2.15m). In the following week, the QCL setup was used for closed-path eddy covariance flux measurement of the carbon dioxide isotopomers, with the air inlet located next to an open-path Infra Red Gas Analyzers (IRGA, LiCor 7500) used simultaneously for carbon dioxide measurements. During this second week, an area of grass inside the footprint was cut and harvested after several days. The first results of in-field continuous QCL measurements of carbon dioxide mixing ratios and their stable isotopic ratios show good agreement with IRGA measurements and isotope analysis of flask samples by IRMS. Thus, QCL spectroscopy is a very promising tool for stable isotope flux investigations.

  9. Stable carbon isotope discrimination in the smut fungus Ustilago violacea

    International Nuclear Information System (INIS)

    Will, O.H. III; Tieszen, L.L.; Kellen, M.; Gerlach, T.

    1986-01-01

    Haploid strains 15.10, I.C429, and I.C2y and diploid strain JK2 of Ustilago Piolacea were grown on one or more of the following carbon sources: glucose, sucrose, maltose, inulin, starch, inositol, glycerol, casein, and yeast extract. The media, both before and after fungal growth, and the fungal cells were analyzed for 13 C/ 12 C content (δ 13 values) using an isotope ratio mass spectrometer after combustion to CO 2 . In all cases, the used and unused media had identical δ 13 C values. Strain 15.10 had significantly less 13 C than the media when grown on glucose, sucrose, maltose, and inositol; significantly more 13 C when grown on inulin, starch, and glycerol; and no significant difference in δ 13 C values when grown on casein and yeast extract media. Other haploid strains responded similarly to 15.10. Diploid strain JK2 was also depleted in 13 C when grown on glucose and enriched in 13 C when grown on glycerol; however, JK2 was slightly depleted in 13 C when grown on casein, whereas all the tested haploid strains were enriched in 13 C

  10. Measurement of organic carbon stable isotope composition of different soil types by EA-IRMS system

    International Nuclear Information System (INIS)

    Qi Biao; Ding Lingling; Cui Jiehua; Wang Yanhong

    2009-01-01

    Element analyzer-isotope ratio mass spectrometers (EA-IRMS) is a rapid and precise method for measuring stable carbon isotope. Pure CO 2 reference gas was calibrated via international standard-Urea, and the δ 13 C us PDB value of pure CO 2 is (-29.523 ± 0.0181)%. Stability and linearity of the EA-IRMS system, precision of δ 13 C measurement for samples were tested through experimental comparison. Moreover, determination method of organic carbon stable isotope in soil was based on the system. The EA-IRMS system had well linearity when ion intensity ranged from 1.0 to 7.0V, and it excelled the total linearity when the ion intensity was from 1.5 to 5.0V, and the accurate result of δ 13 C for sample analysis could be obtained with precision of 0.015%. If carbon content in sample is more than 5μg, the requirement for analyzing accurate result of δ 13 C could be achieved. The organic carbon stable isotope was measured in 18 different types soil samples, the average natural abundance of 13 C was 1.082%, and the organic carbon stable isotope composition was significantly different among different type soils. (authors)

  11. Simultaneous determination of stable carbon, oxygen, and hydrogen isotopes in cellulose.

    Science.gov (United States)

    Loader, N J; Street-Perrott, F A; Daley, T J; Hughes, P D M; Kimak, A; Levanič, T; Mallon, G; Mauquoy, D; Robertson, I; Roland, T P; van Bellen, S; Ziehmer, M M; Leuenberger, M

    2015-01-06

    A technological development is described through which the stable carbon-, oxygen-, and nonexchangeable hydrogen-isotopic ratios (δ(13)C, δ(18)O, δ(2)H) are determined on a single carbohydrate (cellulose) sample with precision equivalent to conventional techniques (δ(13)C 0.15‰, δ(18)O 0.30‰, δ(2)H 3.0‰). This triple-isotope approach offers significant new research opportunities, most notably in physiology and medicine, isotope biogeochemistry, forensic science, and palaeoclimatology, when isotopic analysis of a common sample is desirable or when sample material is limited.

  12. Molecular and stable carbon isotopic characterization of PAH contaminants at McMurdo Station, Antarctica

    International Nuclear Information System (INIS)

    Kim, Moonkoo . E-mail moonkoo.kim@wmich.edu; Kennicutt, Mahlon C.; Qian Yaorong

    2006-01-01

    The molecular and stable carbon isotopic compositions of contaminant polycyclic aromatic hydrocarbons (PAHs) at McMurdo Station, Antarctica were analyzed in samples collected from land and sub-tidal area. PAHs in the study areas were characterized by high amounts of naphthalene and alkylated naphthalenes from petroleum products introduced by human activities in the area. Principal component analysis (PCA) of PAH composition data identified multiple sources of PAH contamination in the study area. Compositional assignments of origins were confirmed using compound specific stable carbon isotopic analysis

  13. Discrimination factors of carbon and nitrogen stable isotopes in meerkat feces

    Directory of Open Access Journals (Sweden)

    Shaena Montanari

    2017-06-01

    Full Text Available Stable isotope analysis of feces can provide a non-invasive method for tracking the dietary habits of nearly any mammalian species. While fecal samples are often collected for macroscopic and genetic study, stable isotope analysis can also be applied to expand the knowledge of species-specific dietary ecology. It is somewhat unclear how digestion changes the isotope ratios of animals’ diets, so more controlled diet studies are needed. To date, most diet-to-feces controlled stable isotope experiments have been performed on herbivores, so in this study I analyzed the carbon and nitrogen stable isotope ratios in the diet and feces of the meerkat (Suricata suricatta, a small omnivorous mammal. The carbon trophic discrimination factor between diet and feces (Δ13Cfeces is calculated to be 0.1 ± 1.5‰, which is not significantly different from zero, and in turn, not different than the dietary input. On the other hand, the nitrogen trophic discrimination factor (Δ15Nfeces is 1.5 ± 1.1‰, which is significantly different from zero, meaning it is different than the average dietary input. Based on data generated in this experiment and a review of the published literature, carbon isotopes of feces characterize diet, while nitrogen isotope ratios of feces are consistently higher than dietary inputs, meaning a discrimination factor needs to be taken into account. The carbon and nitrogen stable isotope values of feces are an excellent snapshot of diet that can be used in concert with other analytical methods to better understand ecology, diets, and habitat use of mammals.

  14. Stable carbon and nitrogen isotopes in vertical peat profiles of natural and drained boreal peatlands

    Science.gov (United States)

    Nykänen, Hannu; Mpamah, Promise; Rissanen, Antti; Pitkänen, Aki; Turunen, Jukka; Simola, Heikki

    2015-04-01

    Peatlands form a significant carbon pool in the global carbon cycle. Change in peat hydrology, due to global warming is projected to change microbiological processes and peat carbon pool. We tested if bulk stable carbon and nitrogen isotopes serve as indicators of severe long term drying in peatlands drained for forestry. Depth profile analysis of peat, for their carbon and nitrogen content as well as their carbon and nitrogen stable isotopic signatures, were conducted for peatlands in southern and eastern Finland, having ombrotrophic and minerotrophic natural and corresponding drained pairs or separate drained sites. The selection of sites allowed us to compare changes due to different fertility and changes due to long term artificial drying. Drainage lasting over 40 years has led to changes in hydrology, vegetation, nutrient mineralization and respiration. Furthermore, increased nutrient uptake and possible recycling of peat nitrogen and carbon trough vegetation back to the peat surface, also possibly has an effect on the stable isotopic composition of peat carbon and nitrogen. We think that drainage induced changes somehow correspond to those caused by changed hydrology due to climate change. We will present data from these measurements and discuss their implications for carbon and nitrogen flows in peatlands.

  15. Stable carbon and oxygen isotope study on benthic foraminifera ...

    Indian Academy of Sciences (India)

    Ajoy K Bhaumik

    2017-07-24

    Jul 24, 2017 ... of a species for isotopic analysis has forced us to select multiple species from down-core samples. Thus ... microhabitat, climatic variability, bottom and pore ...... Trends, rhythms, and aberrations in global climate 65 Ma.

  16. Stable carbon and nitrogen isotope ratios of sodium and potassium cyanide as a forensic signature.

    Science.gov (United States)

    Kreuzer, Helen W; Horita, Juske; Moran, James J; Tomkins, Bruce A; Janszen, Derek B; Carman, April

    2012-01-01

    Sodium and potassium cyanide are highly toxic, produced in large amounts by the chemical industry, and linked to numerous high-profile crimes. The U.S. Centers for Disease Control and Prevention has identified cyanide as one of the most probable agents to be used in a chemical terrorism event. We investigated whether stable C and N isotopic content of sodium and potassium cyanide could serve as a forensic signature for sample matching, using a collection of 65 cyanide samples. Upon analysis, a few of the cyanide samples displayed nonhomogeneous isotopic content associated with degradation to a carbonate salt and loss of hydrogen cyanide. Most samples had highly reproducible isotope content. Of the 65 cyanide samples, >95% could be properly matched based on C and N isotope ratios, with a false match rate <3%. These results suggest that stable C and N isotope ratios are a useful forensic signature for matching cyanide samples. © 2011 American Academy of Forensic Sciences.

  17. Stable carbon isotope ratios: implications for the source of sediment carbon and for phytoplankton carbon assimilation in Lake Memphremagog, Quebec

    International Nuclear Information System (INIS)

    LaZerte, B.D.

    1983-01-01

    The stable carbon isotope (SCI) ratio of the sediment of Lake Memphremagog, Quebec is compared with that ot terrestrial sources and the phytoplankton to determine the relative proportion of allochthonous carbon incorporated into the sediments. Approximately 40-50% of the organic carbon in the main basins' pelagic sediment was terrestrial in origin, whereas up to 100% was terrestrial in littoral areas. The SCI method of determining the organic carbon source of sediments appears more reliable than the C/N method. A comparison of the SCI fractionation of the phytoplankton with laboratory cultures under different degrees of carbon limitation indicates that the phytoplankton of Lake Memphremagog are not carbon limited and fix carbon primarily by the C 3 pathway

  18. FATTY ACID STABLE ISOTOPE INDICATORS OF MICROBIAL CARBON SOURCE IN TROPICAL SOILS

    Science.gov (United States)

    The soil microbial community plays an important role in tropical ecosystem functioning because of its importance in the soil organic matter (SOM) cycle. We have measured the stable carbon isotopic ratio (delta13C) of individual phospholipid fatty acids (PLFAs) in a variety of tr...

  19. ANALYTICAL EMPLOYMENT OF STABLE ISOTOPES OF CARBON, NITROGEN, OXYGEN AND HYDROGEN FOR FOOD AUTHENTICATION

    Directory of Open Access Journals (Sweden)

    E. Novelli

    2011-04-01

    Full Text Available Stable isotopes of carbon, nitrogen, oxygen and hydrogen were used for analytical purposes for the discrimination of the type of production (farming vs. fishing in the case of sea bass and for geographical origin in the case of milk. These results corroborate similar experimental evidences and confirm the potential of this analytical tool to support of food traceability.

  20. 61 stable isotope compositions of organic carbon and contents of ...

    African Journals Online (AJOL)

    Mgina

    isotope record from Lake Ndutu shows a general downcore decrease in δ. 13C values ... in bulk δ13C of the terrestrial biomass in the tropics may ... CO2, temperature, moisture conditions and ... A map showing location of sampling sites of Ngorongoro Crater, Lake Ndutu and .... the Lakes Makat and Masek records cannot.

  1. Separation of polybrominated diphenyl ethers in fish for compound-specific stable carbon isotope analysis

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Yan-Hong [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Graduate University of Chinese Academy of Sciences, Beijing, 100049 (China); Luo, Xiao-Jun, E-mail: luoxiaoj@gig.ac.cn [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Chen, Hua-Shan; Wu, Jiang-Ping; Chen, She-Jun; Mai, Bi-Xian [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China)

    2012-05-15

    A separation and isotopic analysis method was developed to accurately measure the stable carbon isotope ratios of polybrominated diphenyl ethers (PBDEs) with three to six substituted bromine atoms in fish samples. Sample extracts were treated with concentrated sulfuric acid to remove lipids, purified using complex silica gel column chromatography, and finally processed using alumina/silica (Al/Si) gel column chromatography. The purities of extracts were verified by gas chromatography and mass spectrometry (GC-MS) in the full-scan mode. The average recoveries of all compounds across the purification method were between 60% and 110%, with the exception of BDE-154. The stable carbon isotopic compositions of PBDEs can be measured with a standard deviation of less than 0.5 Per-Mille-Sign . No significant isotopic fraction was found during the purification of the main PBDE congeners. A significant change in the stable carbon isotope ratio of BDE-47 was observed in fish carcasses compared to the original isotopic signatures, implying that PBDE stable carbon isotopic compositions can be used to trace the biotransformation of PBDEs in biota. - Highlights: Black-Right-Pointing-Pointer A method for the purification of PBDEs for CSIA was developed. Black-Right-Pointing-Pointer The {delta}{sup 13}C of PBDE congeners can be measured with a standard deviation of less than 0.5 Per-Mille-Sign . Black-Right-Pointing-Pointer Common carp were exposed to a PBDE mixture to investigate debromination. Black-Right-Pointing-Pointer Ratios of the {delta}{sup 13}C values can be used to trace the debromination of PBDE in fish.

  2. Monitoring in situ biodegradation of hydrocarbons by using stable carbon isotopes

    International Nuclear Information System (INIS)

    Aggarwal, P.K.; Hinchee, R.E.

    1991-01-01

    Spilled or leaked nonhalogenated petroleum hydrocarbons in the soil can generally be metabolized by indigenous, aerobic bacteria. In situ biological degradation of hydrocarbons may be accelerated by supplying inorganic nutrients and/or oxygen. Approaches to monitoring and verifying enhanced in situ biodegradation have included measurements of changes over time in the (a) concentration of hydrocarbons, (b) temperature, (c) number of hydrocarbon-degrading microorganisms, (d) ratio of fast-degrading hydrocarbons (e.g., pristanes or phytanes), and (e) metabolic intermediates. Measurements of oxygen consumption over time and elevated carbon dioxide concentrations in soil gas also have been used as indicators of hydrocarbon degradation. An alternative approach that may help substantiate biodegradation is to measure stable carbon isotope ratios in soil gas CO 2 . Stable carbon isotope ratio analysis is inexpensive and commercially available at many laboratories. Carbon dioxide produced by hydrocarbon degradation may be distinguished from that produced by other processes based on the carbon isotopic compositions characteristic of the source material and/or fractionation accompanying microbial metabolism. Here the authors demonstrate the applicability of the stable isotope technique for monitoring enhanced. aerobic biodegradation of hydrocarbons using data from three locations in the United States

  3. Late Glacial Tropical Savannas in Sundaland Inferred From Stable Carbon Isotope Records of Cave Guano

    Science.gov (United States)

    Wurster, C. M.; Bird, M. I.; Bull, I.; Dungait, J.; Bryant, C. L.; Ertunç, T.; Hunt, C.; Lewis, H. A.; Paz, V.

    2008-12-01

    During the Last Glacial Period (LGP), reduced global sea level exposed the continental shelf south of Thailand to Sumatra, Java, and Borneo to form the contiguous continent of Sundaland. However, the type and extent of vegetation that existed on much of this exposed landmass during the LGP remains speculative. Extensive bird and bat guano deposits in caves throughout this region span beyond 40,000 yr BP, and contain a wealth of untapped stratigraphic palaeoenvironmental information. Stable carbon isotope ratios of insectivorous bird and bat guano contain a reliable record of the animal's diet and, through non-specific insect predation, reflect the relative abundance of major physiological pathways in plants. Various physiological pathways of carbon fixation in plants yield differing stable carbon isotope ratios. Stable carbon isotope values of C3 plants are lower than C4 vegetation due to different enzymatic discriminations of the heavy isotope through the carbon fixing pathways. In tropical locales, grasses nearly always follow the C4 photosynthetic pathway, whereas tropical rainforest uses C3 photosynthesis, providing a proxy for vegetation and therefore climate change in the past. Here we discuss four guano stable-isotope records, based on insect cuticle and n-alkane analysis, supplemented by pollen analysis. All sites suggest a C3 dominated ecosystem for the Holocene, consistent with the wet tropical forest vegetation present at all locations. Two sites from Palawan Island, Philippines, record stable carbon isotope values of guano that document a drastic change from C3 (forest) to C4 (savanna) dominated ecosystems during the Last Glacial Maximum (LGM). A third location, at Niah Great Cave, Malaysia, indicates C3-dominant vegetation throughout the record, but does display variation in stable carbon isotope values likely linked to humidity changes. A fourth location, Batu Caves in Peninsular Malaysia, also indicates open vegetation during the LGM. Vegetation

  4. The relationship between carbon stable isotope ratios of hatchling down and egg yolk in Black-headed Gulls

    NARCIS (Netherlands)

    Klaassen, M.R.J.; Baarspul, T.; Dekkers, T.; Van Tienen, P.

    2004-01-01

    We reconstructed the nutrient source for egg synthesis by sampling Black-headed Gull (Larus ridibundus) eggs for yolk, analyzing their carbon stable isotope ratio, and comparing that to hatchling down. Most of the variation in carbon stable isotope ratio was explained by differences between nests,

  5. Stable carbon isotope composition of organic material and carbonate in sediment of a swamp and lakes in Honshu island, Japan

    International Nuclear Information System (INIS)

    Ishizuka, Toshio

    1978-01-01

    Recent sediments from a swamp and lakes in Honshu were analyzed for organic carbon and carbonate contents, and stable isotope ratios of carbon in the organic materials and carbonate. delta C 13 values of the carbonate tend to be distinctly larger than those of organic carbon in reducing condition as natural gas field, whereas in oxidizing SO 4 -reducing conditions, they are slightly larger than those of organic carbon within the limited range of a few per mil. Carbon isotopic compositions of organic carbon in sediment of the swamp, Obuchi-numa, were analyzed and compared with habitat analysis of associated fossil diatoms. deltaC 13 values of organic carbon in the sediment vary in correlation with the species abundance in habitat of the associated fossil diatoms, ranging from fresh-water (-0.0282) to coastal marine (-0.0236) via brackish. (auth.)

  6. Simulation of dual carbon-bromine stable isotope fractionation during 1,2-dibromoethane degradation.

    Science.gov (United States)

    Jin, Biao; Nijenhuis, Ivonne; Rolle, Massimo

    2018-06-01

    We performed a model-based investigation to simultaneously predict the evolution of concentration, as well as stable carbon and bromine isotope fractionation during 1,2-dibromoethane (EDB, ethylene dibromide) transformation in a closed system. The modelling approach considers bond-cleavage mechanisms during different reactions and allows evaluating dual carbon-bromine isotopic signals for chemical and biotic reactions, including aerobic and anaerobic biological transformation, dibromoelimination by Zn(0) and alkaline hydrolysis. The proposed model allowed us to accurately simulate the evolution of concentrations and isotope data observed in a previous laboratory study and to successfully identify different reaction pathways. Furthermore, we illustrated the model capabilities in degradation scenarios involving complex reaction systems. Specifically, we examined (i) the case of sequential multistep transformation of EDB and the isotopic evolution of the parent compound, the intermediate and the reaction product and (ii) the case of parallel competing abiotic pathways of EDB transformation in alkaline solution.

  7. Growth versus metabolic tissue replacement in mouse tissues determined by stable carbon and nitrogen isotope analysis

    Science.gov (United States)

    Macavoy, S. E.; Jamil, T.; Macko, S. A.; Arneson, L. S.

    2003-12-01

    Stable isotope analysis is becoming an extensively used tool in animal ecology. The isotopes most commonly used for analysis in terrestrial systems are those of carbon and nitrogen, due to differential carbon fractionation in C3 and C4 plants, and the approximately 3‰ enrichment in 15N per trophic level. Although isotope signatures in animal tissues presumably reflect the local food web, analysis is often complicated by differential nutrient routing and fractionation by tissues, and by the possibility that large organisms are not in isotopic equilibrium with the foods available in their immediate environment. Additionally, the rate at which organisms incorporate the isotope signature of a food through both growth and metabolic tissue replacement is largely unknown. In this study we have assessed the rate of carbon and nitrogen isotopic turnover in liver, muscle and blood in mice following a diet change. By determining growth rates, we were able to determine the proportion of tissue turnover caused by growth versus that caused by metabolic tissue replacement. Growth was found to account for approximately 10% of observed tissue turnover in sexually mature mice (Mus musculus). Blood carbon was found to have the shortest half-life (16.9 days), followed by muscle (24.7 days). Liver carbon turnover was not as well described by the exponential decay equations as other tissues. However, substantial liver carbon turnover was observed by the 28th day after diet switch. Surprisingly, these tissues primarily reflect the carbon signature of the protein, rather than carbohydrate, source in their diet. The nitrogen signature in all tissues was enriched by 3 - 5‰ over their dietary protein source, depending on tissue type, and the isotopic turnover rates were comparable to those observed in carbon.

  8. Measurement of stable isotope ratio of organic carbon in water samples

    International Nuclear Information System (INIS)

    Fujii, Toshihiro; Otsuki, Akira

    1977-01-01

    A new method for the measurement of stable isotope ratios was investigated and applied to organic carbon's isotope ratio measurements in water samples. A few river water samples from Tsuchiura city were tested. After the wet oxidation of organic carbons to carbon dioxide in a sealed ampoule, the isotope ratios were determined with the gas chromatograph-quadrupole mass spectrometer combined with a total organic carbon analyser, under the dynamic conditions. The GC-MS had been equipped with the multiple ion detector-digital integrator system. The ion intensities at m/e 44 and 45 were simultaneously measured at a switching rate of 1 ms. The measurements with carbon dioxide acquired from sodium carbonate (53 μg) gave the isotope ratios with the variation coefficient of 0.62%. However, the variation coefficients obtained from organic carbons in natural water samples were 2 to 3 times as high as that from sodium carbonate. This method is simple and rapid and may be applied to various fields especially in biology and medicine. (auth.)

  9. Geochemistry of carbon stable isotopes in the sea

    International Nuclear Information System (INIS)

    Duplessy, Jean-Claude

    1972-01-01

    This paper describes geochemical process which affect the distribution in the sea of the 13 C/ 12 C ratio of total inorganic dissolved CO 2 ; synthesis of the biomass and respiratory phenomena; oxidation of organic matter; dissolution of carbonates; run off waters; exchange of CO 2 between sea and atmosphere. Some applications to the paleoclimatology are presented. (author) [fr

  10. The stable carbon isotope ratios in benthic food webs of the gulf of Calvi, Corsica

    Science.gov (United States)

    Dauby, Patrick

    1989-02-01

    The Gulf of Calvi, Corsica, presents a wide diversity of biocoenoses, amongst which the seagrass Posidonia meadow is prevalent. More than 100 plant, animal and sediment samples from various biotopes were analysed for their stable carbon isotope ratios, to assess carbon flows within the food chains. Marine plants display a wide range of δ 13C values, from -6 to -32‰ but with three relatively well distinct peaks for Posidonia, brown algae and phytoplankton (-9, -19 and -23‰, respectively), which are the main carbon sources. The range of isotopic values of animals is narrower, from -14 to -24‰, suggesting that they feed mainly on algae and plankton. Computations based on simple equations show the proportion of each carbon source in the diet of the animals. Posidonia, notwithstanding their important biomass, appear to be a minor food source; this is possibly because of the transfer of their dead leaves, towards the shorelines, in winter.

  11. Effect of Different Carbon Substrates on Nitrate Stable Isotope Fractionation During Microbial Denitrification

    DEFF Research Database (Denmark)

    Wunderlich, Anja; Meckenstock, Rainer; Einsiedl, Florian

    2012-01-01

    -labeled water and 18O-labeled nitrite were added to the microcosm experiments to study the effect of putative backward reactions of nitrite to nitrate on the stable isotope fractionation. We found no evidence for a reverse reaction. Significant variations of the stable isotope enrichment factor ε were observed......In batch experiments, we studied the isotope fractionation in N and O of dissolved nitrate during dentrification. Denitrifying strains Thauera aromatica and “Aromatoleum aromaticum strain EbN1” were grown under strictly anaerobic conditions with acetate, benzoate, and toluene as carbon sources. 18O...... of nitrate transport across the cell wall compared to the kinetics of the intracellular nitrate reduction step of microbial denitrification....

  12. Effects of euthanasia method on stable-carbon and stable-nitrogen isotope analysis for an ectothermic vertebrate.

    Science.gov (United States)

    Atwood, Meredith A

    2013-04-30

    Stable isotope analysis is a critical tool for understanding ecological food webs; however, results can be sensitive to sample preparation methods. To limit the possibility of sample contamination, freezing is commonly used to euthanize invertebrates and preserve non-lethal samples from vertebrates. For destructive sampling of vertebrates, more humane euthanasia methods are preferred to freezing and it is essential to evaluate how these euthanasia methods affect stable isotope results. Stable isotope ratios and elemental composition of carbon and nitrogen were used to evaluate whether the euthanasia method compromised the integrity of the sample for analysis. Specifically, the stable isotope and C:N ratios were compared for larval wood frogs (Rana sylvatica  =  Lithobates sylvaticus), an ectothermic vertebrate, that had been euthanized by freezing with four different humane euthanasia methods: CO2, benzocaine, MS-222 (tricaine methanesulfonate), and 70% ethanol. The euthanasia method was not related to the δ(13)C or δ(15)N values and the comparisons revealed no differences between freezing and any of the other treatments. However, there were slight (non-significant) differences in the isotope ratios of benzocaine and CO2 when each was compared with freezing. The elemental composition was altered by the euthanasia method employed. The percentage nitrogen was higher in CO2 treatments than in freezing, and similar (non-significant) trends were seen for ethanol treatments relative to freezing. The resulting C:N ratios were higher for benzocaine treatments than for both CO2 and ethanol. Similar (non-significant) trends suggested that the C:N ratios were also higher for animals euthanized by freezing than for both CO2 and ethanol euthanasia methods. The euthanasia method had a larger effect on elemental composition than stable isotope ratios. The percentage nitrogen and the subsequent C:N ratios were most affected by the CO2 and ethanol euthanasia methods, whereas

  13. Organic carbon and nitrogen stable isotopes in the intertidal sediments from the Yangtze Estuary, China

    International Nuclear Information System (INIS)

    Liu, M. . E-mail mliu@geo.ecnu.edu.cn; Hou, L.J.; Xu, S.Y.; Ou, D.N.; Yang, Y.; Yu, J.; Wang, Q.

    2006-01-01

    The natural isotopic compositions and C/N elemental ratios of sedimentary organic matter were determined in the intertidal flat of the Yangtze Estuary. The results showed that the ratios of carbon and nitrogen stable isotopes were respectively -29.8 per mille to - 26.0 per mille and 1.6 per mille -5.5 per mille in the flood season (July), while they were -27.3 per mille to - 25.6 per mille and 1.7 per mille -7.8 per mille in the dry season (February), respectively. The δ 13 C signatures were remarkably higher in July than in February, and gradually increased from the freshwater areas to the brackish areas. In contrast, there were relatively complex seasonal and spatial changes in stable nitrogen isotopes. It was also reflected that δ 15 N and C/N compositions had been obviously modified by organic matter diagenesis and biological processing, and could not be used to trace the sources of organic matter at the study area. In addition, it was considered that the mixing inputs of terrigenous and marine materials generally dominated sedimentary organic matter in the intertidal flat. The contribution of terrigenous inputs to sedimentary organic matter was roughly estimated according to the mixing balance model of stable carbon isotopes

  14. Stable carbon isotopes as an indicator for soil degradation in an alpine environment (Urseren Valley, Switzerland).

    Science.gov (United States)

    Schaub, Monika; Alewell, Christine

    2009-05-01

    Analyses of soil organic carbon (SOC) content and stable carbon isotope signatures (delta(13)C) of soils were assessed for their suitability to detect early stage soil erosion. We investigated the soils in the alpine Urseren Valley (southern central Switzerland) which are highly impacted by soil erosion. Hill slope transects from uplands (cambisols) to adjacent wetlands (histosols and histic to mollic gleysols) differing in their intensity of visible soil erosion, and reference wetlands without erosion influence were sampled. Carbon isotopic signature and SOC content of soil depth profiles were determined. A close correlation of delta(13)C and carbon content (r > 0.80) is found for upland soils not affected by soil erosion, indicating that depth profiles of delta(13)C of these upland soils mainly reflect decomposition of SOC. Long-term disturbance of an upland soil is indicated by decreasing correlation of delta(13)C and SOC (r soil erosion in hill slope transects from uplands to adjacent wetlands is documented as an intermediate delta(13)C value (-27.5 per thousand) for affected wetland soil horizons (0-12 cm) between upland (aerobic metabolism, relatively heavier delta(13)C of -26.6 per thousand) and wetland isotopic signatures (anaerobic metabolism, relatively lighter delta(13)C of -28.6 per thousand). Carbon isotopic signature and SOC content are found to be sensitive indicators of short- and long-term soil erosion processes. Copyright (c) 2009 John Wiley & Sons, Ltd.

  15. A free-air system for long-term stable carbon isotope labeling of adult forest trees

    Science.gov (United States)

    Stable carbon (C) isotopes, in particular employed in labeling experiments, are an ideal tool to broaden our understanding of C dynamics in trees and forest ecosystems. Here, we present a free-air exposure system, named isoFACE, designed for long-term stable C isotope labeling in...

  16. The synthesis of tritium, carbon-14 and stable isotope labelled selective estrogen receptor degraders.

    Science.gov (United States)

    Bragg, Ryan A; Bushby, Nick; Ericsson, Cecilia; Kingston, Lee P; Ji, Hailong; Elmore, Charles S

    2016-09-01

    As part of a Medicinal Chemistry program aimed at developing an orally bioavailable selective estrogen receptor degrader, a number of tritium, carbon-14, and stable isotope labelled (E)-3-[4-(2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenyl]prop-2-enoic acids were required. This paper discusses 5 synthetic approaches to this compound class. Copyright © 2016 John Wiley & Sons, Ltd.

  17. Stable carbon isotope fractionation during the biodegradation of lambda-cyhalothrin.

    Science.gov (United States)

    Shen, Xiaoli; Xu, Zemin; Zhang, Xichang; Yang, Fangxing

    2015-11-01

    In this study, the microbial degradation of lambda-cyhalothrin in soil was investigated using compound-specific stable isotope analysis. The results revealed that lambda-cyhalothrin was biodegraded in soil under laboratory conditions. The half-lives of lambda-cyhalothrin were determined to be 49 and 161 days in non-sterile and sterile soils spiked with 2mg/kg lambda-cyhalothrin and 84 and 154 days in non-sterile and sterile soils spiked with 10mg/kg lambda-cyhalothrin, respectively. The biodegradation of lambda-cyhalothrin resulted in carbon isotope fractionation, which shifted from -29.0‰ to -26.5‰ in soil spiked with 2mg/kg lambda-cyhalothrin, and to -27.5‰ with 10mg/kg lambda-cyhalothrin. A relationship was established between the stable carbon isotope fraction and the residual concentrations of lambda-cyhalothrin by the Rayleigh equation in which the carbon isotope enrichment factor ε of the microbial degradation of lambda-cyhalothrin in the soil was calculated as -2.53‰. This study provides an approach to quantitatively evaluate the biodegradation of lambda-cyhalothrin in soil in field studies. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Carbon Stable Isotope Values in Plankton and Mussels Reflect Changes in Carbonate Chemistry Associated with Nutrient Enhanced Net Production

    Science.gov (United States)

    Coastal ecosystems are inherently complex and potentially adaptive as they respond to changes in nutrient loads and climate. We documented the role that carbon stable isotope (δ13C) measurements could play in understanding that adaptation with a series of three Ecostat (i.e...

  19. Stable carbon isotopic composition of gasolines determined by isotope ratio monitoring gas chromatography mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Smallwood, B.J.; Philp, R.P.; Allen, J.D. [University of Oklahoma, Norman, OK (United States). School of Geology and Geophysics

    2002-07-01

    A large number of underground gasoline storage facilities in the United States continuously leak gasoline into the subsurface, which makes gasoline a major groundwater contaminant. Gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) are used currently to characterize contaminated groundwater and soils. Correlations of contaminants with suspected source(s) are extremely difficult by these techniques because many gasolines have similar hydrocarbon distributions. The present study applied the technique of isotope ratio monitoring gas chromatography-mass spectrometry (irmGC-MS) to 19 gasoline samples from different areas of the USA. This allows a much better correlation of gasoline contaminants to source. Data obtained indicate a wide range of {sup {delta}}{sup 13}C values for 16 ubiquitous compounds in the gasolines. The majority of samples could be distinguished from each other on the basis of {sup {delta}}{sup 13}C hydrocarbon composition. The oxygenated additive methyl tertiary butyl ether (MTBE) was present in ten of the gasolines analyzed, and had a relatively narrow range of {sup {delta}}{sup 13}C values (-30.4 to -28.3 per mille). Preliminary investigations were also made to determine the extent of carbon isotopic fractionation after simple water washing and evaporation experiments. Results indicate that the majority of compounds did not undergo significant carbon isotopic fractionation as a result of these processes. (author)

  20. Stable carbon isotope depth profiles and soil organic carbon dynamics in the lower Mississippi Basin

    Science.gov (United States)

    Wynn, J.G.; Harden, J.W.; Fries, T.L.

    2006-01-01

    Analysis of depth trends of 13C abundance in soil organic matter and of 13C abundance from soil-respired CO2 provides useful indications of the dynamics of the terrestrial carbon cycle and of paleoecological change. We measured depth trends of 13C abundance from cropland and control pairs of soils in the lower Mississippi Basin, as well as the 13C abundance of soil-respired CO2 produced during approximately 1-year soil incubation, to determine the role of several candidate processes on the 13C depth profile of soil organic matter. Depth profiles of 13C from uncultivated control soils show a strong relationship between the natural logarithm of soil organic carbon concentration and its isotopic composition, consistent with a model Rayleigh distillation of 13C in decomposing soil due to kinetic fractionation during decomposition. Laboratory incubations showed that initially respired CO 2 had a relatively constant 13C content, despite large differences in the 13C content of bulk soil organic matter. Initially respired CO2 was consistently 13C-depleted with respect to bulk soil and became increasingly 13C-depleted during 1-year, consistent with the hypothesis of accumulation of 13C in the products of microbial decomposition, but showing increasing decomposition of 13C-depleted stable organic components during decomposition without input of fresh biomass. We use the difference between 13C / 12C ratios (calculated as ??-values) between respired CO 2 and bulk soil organic carbon as an index of the degree of decomposition of soil, showing trends which are consistent with trends of 14C activity, and with results of a two-pooled kinetic decomposition rate model describing CO2 production data recorded during 1 year of incubation. We also observed inconsistencies with the Rayleigh distillation model in paired cropland soils and reasons for these inconsistencies are discussed. ?? 2005 Elsevier B.V. All rights reserved.

  1. Arctic herbivore diet can be inferred from stable carbon and nitrogen isotopes in C3 plants, faeces and wool

    DEFF Research Database (Denmark)

    Kristensen, Ditte; Kristensen, Erik; Forchhammer, Mads C.

    2011-01-01

    The use of stable isotopes in diet analysis usually relies on the different photosynthetic pathways of C3 and C4 plants, and the resulting difference in carbon isotope signature. In the Arctic, however, plant species are exclusively C3, and carbon isotopes alone are therefore not suitable......% graminoids and up to 20% willows. In conclusion, the diet composition of an arctic herbivore can indeed be inferred from stable isotopes in arctic areas, despite the lack of C4 plants...... for studying arctic herbivore diets. In this study, we examined the potential of both stable carbon and nitrogen isotopes to reconstruct the diet of an arctic herbivore, here the muskox (Ovibos moschatus (Zimmermann, 1780)), in northeast Greenland. The isotope composition of plant communities and functional...

  2. Investigating Pathways of Nutrient and Energy Flows Through Aquatic Food Webs Using Stable Isotopes of Carbon and Nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Hadwen, W. L.; Bunn, S. E. [Australian Rivers Institute, Griffith School of Environment, Griffith University, Nathan Campus, Brisbane, Queensland (Australia)

    2013-05-15

    Carbon and nitrogen stable isotopes can provide valuable insights into pathways of nutrient and energy flows in aquatic ecosystems. Carbon stable isotopes are principally used to trace pathways of organic matter transfer through aquatic food webs, particularly with regard to identifying the dominant sources of nutrition for aquatic biota. Stable isotopes of carbon have been widely used to answer one of the most pressing questions in aquatic food web ecology - to what degree do in-stream (autochthonous) and riparian (allochthonous) sources of energy fuel riverine food webs? In conjunction with carbon stable isotopes, nitrogen stable isotopes have been used to determine the trophic position of consumers and to identify the number of trophic levels in aquatic food webs. More recently, stable nitrogen isotopes have been recommended as indicators of anthropogenic disturbances. Specifically, agricultural land uses and/or sewage effluent discharge have been shown to significantly increase {delta}{sup 15}N signatures in primary producers and higher order consumers in freshwater, estuarine and marine environments. Together, carbon and nitrogen stable isotopes can be used to examine natural food web functions as well as the degree to which human modifications to catchments and aquatic environments can influence aquatic ecosystem function. (author)

  3. Stable carbon isotope fractionation during the biodegradation of lambda-cyhalothrin

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Xiaoli [MOE Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Department of Environmental Engineering, Quzhou University, Quzhou 324000 (China); Xu, Zemin [MOE Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Zhang, Xichang [Laboratory for Teaching in Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Yang, Fangxing, E-mail: fxyang@zju.edu.cn [MOE Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Department of Effect-Directed Analysis, Helmholtz Centre for Environmental Research — UFZ, Leipzig 04318 (Germany)

    2015-11-01

    In this study, the microbial degradation of lambda-cyhalothrin in soil was investigated using compound-specific stable isotope analysis. The results revealed that lambda-cyhalothrin was biodegraded in soil under laboratory conditions. The half-lives of lambda-cyhalothrin were determined to be 49 and 161 days in non-sterile and sterile soils spiked with 2 mg/kg lambda-cyhalothrin and 84 and 154 days in non-sterile and sterile soils spiked with 10 mg/kg lambda-cyhalothrin, respectively. The biodegradation of lambda-cyhalothrin resulted in carbon isotope fractionation, which shifted from − 29.0‰ to − 26.5‰ in soil spiked with 2 mg/kg lambda-cyhalothrin, and to − 27.5‰ with 10 mg/kg lambda-cyhalothrin. A relationship was established between the stable carbon isotope fraction and the residual concentrations of lambda-cyhalothrin by the Rayleigh equation in which the carbon isotope enrichment factor ε of the microbial degradation of lambda-cyhalothrin in the soil was calculated as − 2.53‰. This study provides an approach to quantitatively evaluate the biodegradation of lambda-cyhalothrin in soil in field studies. - Highlights: • Abiotic and biotic degradation of lambda-cyhalothrin were observed in soil. • Biodegradation of lambda-cyhalothrin was evaluated by CSIA. • Biodegradation of lambda-cyhalothrin leads to carbon isotope fractionation. • An enrichment factor ε of lambda-cyhalothrin was determined as − 2.53‰.

  4. Stable carbon isotope fractionation during the biodegradation of lambda-cyhalothrin

    International Nuclear Information System (INIS)

    Shen, Xiaoli; Xu, Zemin; Zhang, Xichang; Yang, Fangxing

    2015-01-01

    In this study, the microbial degradation of lambda-cyhalothrin in soil was investigated using compound-specific stable isotope analysis. The results revealed that lambda-cyhalothrin was biodegraded in soil under laboratory conditions. The half-lives of lambda-cyhalothrin were determined to be 49 and 161 days in non-sterile and sterile soils spiked with 2 mg/kg lambda-cyhalothrin and 84 and 154 days in non-sterile and sterile soils spiked with 10 mg/kg lambda-cyhalothrin, respectively. The biodegradation of lambda-cyhalothrin resulted in carbon isotope fractionation, which shifted from − 29.0‰ to − 26.5‰ in soil spiked with 2 mg/kg lambda-cyhalothrin, and to − 27.5‰ with 10 mg/kg lambda-cyhalothrin. A relationship was established between the stable carbon isotope fraction and the residual concentrations of lambda-cyhalothrin by the Rayleigh equation in which the carbon isotope enrichment factor ε of the microbial degradation of lambda-cyhalothrin in the soil was calculated as − 2.53‰. This study provides an approach to quantitatively evaluate the biodegradation of lambda-cyhalothrin in soil in field studies. - Highlights: • Abiotic and biotic degradation of lambda-cyhalothrin were observed in soil. • Biodegradation of lambda-cyhalothrin was evaluated by CSIA. • Biodegradation of lambda-cyhalothrin leads to carbon isotope fractionation. • An enrichment factor ε of lambda-cyhalothrin was determined as − 2.53‰

  5. Factors that control the stable carbon isotopic composition of methane produced in an anoxic marine sediment

    Science.gov (United States)

    Alperin, M. J.; Blair, Neal E.; Albert, D. B.; Hoehler, T. M.; Martens, C. S.

    1993-01-01

    The carbon isotopic composition of methane produced in anoxic marine sediment is controlled by four factors: (1) the pathway of methane formation, (2) the isotopic composition of the methanogenic precursors, (3) the isotope fractionation factors for methane production, and (4) the isotope fractionation associated with methane oxidation. The importance of each factor was evaluated by monitoring stable carbon isotope ratios in methane produced by a sediment microcosm. Methane did not accumulate during the initial 42-day period when sediment contained sulfate, indicating little methane production from 'noncompetitive' substrates. Following sulfate depletion, methane accumulation proceeded in three distinct phases. First, CO2 reduction was the dominant methanogenic pathway and the isotopic composition of the methane produced ranged from -80 to -94 per thousand. The acetate concentration increased during this phase, suggesting that acetoclastic methanogenic bacteria were unable to keep pace with acetate production. Second, acetate fermentation became the dominant methanogenic pathway as bacteria responded to elevated acetate concentrations. The methane produced during this phase was progressively enriched in C-13, reaching a maximum delta(C-13) value of -42 per thousand. Third, the acetate pool experienced a precipitous decline from greater than 5 mM to less than 20 micro-M and methane production was again dominated by CO2 reduction. The delta(C-13) of methane produced during this final phase ranged from -46 to -58 per thousand. Methane oxidation concurrent with methane production was detected throughout the period of methane accumulation, at rates equivalent to 1 to 8 percent of the gross methane production rate. Thus methane oxidation was too slow to have significantly modified the isotopic signature of methane. A comparison of microcosm and field data suggests that similar microbial interactions may control seasonal variability in the isotopic composition of methane

  6. Using stable isotopes of carbon and nitrogen as in-situ tracers for monitoring the natural attenuation of explosives

    National Research Council Canada - National Science Library

    Miyares, Paul H

    1999-01-01

    The use of carbon and nitrogen stable isotope measurements from TNT was examined as a possible tool for monitoring the natural attenuation of TNT incubation studies of spiked soil samples were conducted...

  7. Stable isotopes of carbon and nitrogen as markers of dietary variation among sociocultural subgroups of Inuit in Greenland

    DEFF Research Database (Denmark)

    Bjerregaard, Peter; Larsen, Christina V L; Dahl-Petersen, Inger K

    2017-01-01

    OBJECTIVES: We assessed the use of stable isotopes of carbon and nitrogen as biomarkers for traditional versus store-bought food among the Inuit. Furthermore, we compared the isotope patterns among sociocultural population groups. METHODS: As a part of a country-wide health survey in Greenland...... food in the diet was estimated at 21% from the mean δ(13) C value, 25% from the mean δ(15) N value, and 23% from the FFQ. CONCLUSION: Nail samples for analysis of stable isotopes of carbon and nitrogen were convenient to collect during a large population health survey among the Inuit. Isotope...

  8. Stable isotope studies

    International Nuclear Information System (INIS)

    Ishida, T.

    1992-01-01

    The research has been in four general areas: (1) correlation of isotope effects with molecular forces and molecular structures, (2) correlation of zero-point energy and its isotope effects with molecular structure and molecular forces, (3) vapor pressure isotope effects, and (4) fractionation of stable isotopes. 73 refs, 38 figs, 29 tabs

  9. Applications of stable isotopes

    International Nuclear Information System (INIS)

    Letolle, R.; Mariotti, A.; Bariac, T.

    1991-06-01

    This report reviews the historical background and the properties of stable isotopes, the methods used for their measurement (mass spectrometry and others), the present technics for isotope enrichment and separation, and at last the various present and foreseeable application (in nuclear energy, physical and chemical research, materials industry and research; tracing in industrial, medical and agronomical tests; the use of natural isotope variations for environmental studies, agronomy, natural resources appraising: water, minerals, energy). Some new possibilities in the use of stable isotope are offered. A last chapter gives the present state and forecast development of stable isotope uses in France and Europe

  10. Stable carbon isotope analyses of nanogram quantities of particulate organic carbon (pollen) with laser ablation nano combustion gas chromatography/isotope ratio mass spectrometry

    NARCIS (Netherlands)

    van Roij, Linda; Sluijs, Appy; Laks, Jelmer J.; Reichart, Gert-Jan

    2017-01-01

    Rationale: Analyses of stable carbon isotope ratios (δ13C values) of organic and inorganic matter remains have been instrumental for much of our understanding of present and past environmental and biological processes. Until recently, the analytical window of such analyses has been limited to

  11. Effects of acid mine drainage on dissolved inorganic carbon and stable carbon isotopes in receiving streams

    International Nuclear Information System (INIS)

    Fonyuy, Ernest W.; Atekwana, Eliot A.

    2008-01-01

    Dissolved inorganic carbon (DIC) constitutes a significant fraction of a stream's carbon budget, yet the role of acid mine drainage (AMD) in DIC dynamics in receiving streams remains poorly understood. The objective of this study was to evaluate spatial and temporal effects of AMD and its chemical evolution on DIC and stable isotope ratio of DIC (δ 13 C DIC ) in receiving streams. We examined spatial and seasonal variations in physical and chemical parameters, DIC, and δ 13 C DIC in a stream receiving AMD. In addition, we mixed different proportions of AMD and tap water in a laboratory experiment to investigate AMD dilution and variable bicarbonate concentrations to simulate downstream and seasonal hydrologic conditions in the stream. Field and laboratory samples showed variable pH, overall decreases in Fe 2+ , alkalinity, and DIC, and variable increase in δ 13 C DIC . We attribute the decrease in alkalinity, DIC loss, and enrichment of 13 C of DIC in stream water to protons produced from oxidation of Fe 2+ followed by Fe 3+ hydrolysis and precipitation of Fe(OH) 3(s) . The extent of DIC decrease and 13 C enrichment of DIC was related to the amount of HCO 3 - dehydrated by protons. The laboratory experiment showed that lower 13 C enrichment occurred in unmixed AMD (2.7 per mille ) when the amount of protons produced was in excess of HCO 3 - or in tap water (3.2 per mille ) where no protons were produced from Fe 3+ hydrolysis for HCO 3 - dehydration. The 13 C enrichment increased and was highest for AMD-tap water mixture (8.0 per mille ) where Fe 2+ was proportional to HCO 3 - concentration. Thus, the variable downstream and seasonal 13 C enrichment in stream water was due in part to: (1) variations in the volume of stream water initially mixed with AMD and (2) to HCO 3 - input from groundwater and seepage in the downstream direction. Protons produced during the chemical evolution of AMD caused seasonal losses of 50 to >98% of stream water DIC. This loss of DIC

  12. Tracing carbon sources through aquatic and terrestrial food webs using amino acid stable isotope fingerprinting.

    Directory of Open Access Journals (Sweden)

    Thomas Larsen

    Full Text Available Tracing the origin of nutrients is a fundamental goal of food web research but methodological issues associated with current research techniques such as using stable isotope ratios of bulk tissue can lead to confounding results. We investigated whether naturally occurring δ(13C patterns among amino acids (δ(13CAA could distinguish between multiple aquatic and terrestrial primary production sources. We found that δ(13CAA patterns in contrast to bulk δ(13C values distinguished between carbon derived from algae, seagrass, terrestrial plants, bacteria and fungi. Furthermore, we showed for two aquatic producers that their δ(13CAA patterns were largely unaffected by different environmental conditions despite substantial shifts in bulk δ(13C values. The potential of assessing the major carbon sources at the base of the food web was demonstrated for freshwater, pelagic, and estuarine consumers; consumer δ(13C patterns of essential amino acids largely matched those of the dominant primary producers in each system. Since amino acids make up about half of organismal carbon, source diagnostic isotope fingerprints can be used as a new complementary approach to overcome some of the limitations of variable source bulk isotope values commonly encountered in estuarine areas and other complex environments with mixed aquatic and terrestrial inputs.

  13. Tracing carbon sources through aquatic and terrestrial food webs using amino acid stable isotope fingerprinting.

    Science.gov (United States)

    Larsen, Thomas; Ventura, Marc; Andersen, Nils; O'Brien, Diane M; Piatkowski, Uwe; McCarthy, Matthew D

    2013-01-01

    Tracing the origin of nutrients is a fundamental goal of food web research but methodological issues associated with current research techniques such as using stable isotope ratios of bulk tissue can lead to confounding results. We investigated whether naturally occurring δ(13)C patterns among amino acids (δ(13)CAA) could distinguish between multiple aquatic and terrestrial primary production sources. We found that δ(13)CAA patterns in contrast to bulk δ(13)C values distinguished between carbon derived from algae, seagrass, terrestrial plants, bacteria and fungi. Furthermore, we showed for two aquatic producers that their δ(13)CAA patterns were largely unaffected by different environmental conditions despite substantial shifts in bulk δ(13)C values. The potential of assessing the major carbon sources at the base of the food web was demonstrated for freshwater, pelagic, and estuarine consumers; consumer δ(13)C patterns of essential amino acids largely matched those of the dominant primary producers in each system. Since amino acids make up about half of organismal carbon, source diagnostic isotope fingerprints can be used as a new complementary approach to overcome some of the limitations of variable source bulk isotope values commonly encountered in estuarine areas and other complex environments with mixed aquatic and terrestrial inputs.

  14. USE OF GC-MS/COMBUSTION/IRMS TO IDENTIFY AND DETERMINE THE STABLE CARBON ISOTOPIC RATIO OF INDIVIDUAL LIPIDS

    Science.gov (United States)

    A system that couples a gas chromatograph (GC) via a split to a quadrapole mass spectrometer (MS) and, through a combustion interface, to an isotope ratio mass spectrometer (IRMS) allows the simultaneous detection of electron impact mass spectra and stable carbon isotope ratio an...

  15. Seasonal changes in stable carbon isotope ratios within annual growth rings of Pinus radiata

    International Nuclear Information System (INIS)

    Walcroft, A.; Silvester, W.; Whitehead, D.; Kelliher, F.

    1997-01-01

    The stable isotope composition of photosynthetically assimilated carbon (δ 13 C) is determined by the ratio of the leaf internal CO 2 concentration (c i ) to that of the ambient air (c a ), and so reflects the contribution of both stomatal conductance (g s ) and the rate of photosynthesis (A). Assimilated carbon which is subsequently laid down as wood in annual growth rings may therefore represent a time integrated record of physiological responses by the whole tree to seasonal changes in the environmental variables regulating growth. We analysed the stable carbon isotope composition of Pinus radiata wood collected from two plantation forest sites in New Zealand which differ markedly in temperature, rainfall and soil characteristics. For both sites, discs were cut from the stem of several trees near ground level and whole wood samples were taken from within individual annual growth rings over a number of years. At one site, diameter bands were installed over the 1994 - 1996 growing seasons in order to date precisely the formation of wood during that time. Trees at each site consistently showed a seasonal pattern in the stable isotope composition of wood within individual growth rings. The amplitude of seasonal δ 13 C variation at the wet and dry sites were 1-2 per thousand and 4 per thousand respectively. Mean δ 13 C values from the wet site were 3 per thousand more 13 C depleted than those from the dry site implying lower water-use efficiency (carbon assimilation per unit transpiration). A process-based, model of stomatal conductance and CO 2 assimilation was combined with a soil-water balance model to estimate the average daily leaf-level intercellular CO 2 concentration (c i ). Over two growing seasons at each site there was generally good agreement between mean canopy-level c i derived from the tree-ring δ 13 C data and modelled leaf-level c i levels. Further, the ratio of annual CO 2 assimilation to transpiration estimated by the model for each site

  16. Stable isotopes labelled compounds

    International Nuclear Information System (INIS)

    1982-09-01

    The catalogue on stable isotopes labelled compounds offers deuterium, nitrogen-15, and multiply labelled compounds. It includes: (1) conditions of sale and delivery, (2) the application of stable isotopes, (3) technical information, (4) product specifications, and (5) the complete delivery programme

  17. Method for determination of stable carbon isotope ratio of methylnitrophenols in atmospheric particulate matter

    Directory of Open Access Journals (Sweden)

    S. Moukhtar

    2011-11-01

    Full Text Available A technique for the measurement of the stable isotope ratio of methylnitrophenols in atmospheric particulate matter is presented. Atmospheric samples from rural and suburban areas were collected for evaluation of the procedure. Particulate matter was collected on quartz fibre filters using dichotomous high volume air samplers. Methylnitrophenols were extracted from the filters using acetonitrile. The sample was then purified using a combination of high-performance liquid chromatography and solid phase extraction. The final solution was then divided into two aliquots. To one aliquot, a derivatising agent, Bis(trimethylsilyltrifluoroacetamide, was added for Gas Chromatography-Mass Spectrometry analysis. The second half of the sample was stored in a refrigerator. For samples with concentrations exceeding 1 ng μl−1, the second half of the sample was used for measurement of stable carbon isotope ratios by Gas Chromatography-Isotope Ratio Mass Spectrometry.

    The procedure described in this paper provides a method for the analysis of methylnitrophenols in atmospheric particulate matter at concentrations as low as 0.3 pg m−3 and for stable isotope ratios with an accuracy of better than ±0.5‰ for concentrations exceeding 100 pg m−3.

    In all atmospheric particulate matter samples analysed, 2-methyl-4-nitrophenol was found to be the most abundant methylnitrophenol, with concentrations ranging from the low pg m−3 range in rural areas to more than 200 pg m−3 in some samples from a suburban location.

  18. Using stable isotopes of nitrogen and carbon to study seabird ecology: applications in the Mediterranean seabird community

    Directory of Open Access Journals (Sweden)

    Manuela G. Forero

    2003-07-01

    Full Text Available The application of the stable isotope technique to ecological studies is becoming increasingly widespread. In the case of seabirds, stable isotopes of nitrogen and carbon have been mainly used as dietary tracers. This approach relieson the fact that food web isotopic signatures are reflected in the tissues of the consumer. In addition to the study of trophic ecology, stable isotopes have been used to track the movement of seabirds across isotopic gradients, as individuals moving between isotopically distinct foodwebs can carry with them information on the location of previous feeding areas. Studies applying the stable isotope methodology to the study of seabird ecology show a clear evolution from broad and descriptive approaches to detailed and individual-based analyses. The purpose of this article is to show the different fields of application of stable isotopes to the study of the seabird ecology. Finally, we illustrate the utility of this technique by considering the particularities of the Mediterranean seabird community, suggesting different ecological questions and conservation problems that could be addressed by using the stable isotope approach in this community.

  19. Authenticity and traceability of vanilla flavors by analysis of stable isotopes of carbon and hydrogen.

    Science.gov (United States)

    Hansen, Anne-Mette Sølvbjerg; Fromberg, Arvid; Frandsen, Henrik Lauritz

    2014-10-22

    Authenticity and traceability of vanilla flavors were investigated using gas chromatography-isotope ratio mass spectrometry (GC-IRMS). Vanilla flavors produced by chemical synthesis (n = 2), fermentation (n = 1), and extracted from two different species of the vanilla orchid (n = 79) were analyzed. The authenticity of the flavor compound vanillin was evaluated on the basis of measurements of ratios of carbon stable isotopes (δ(13)C). It was found that results of δ(13)C for vanillin extracted from Vanilla planifolia and Vanilla tahitensis were significantly different (t test) and that it was possible to differentiate these two groups of natural vanillin from vanillin produced otherwise. Vanilla flavors were also analyzed for ratios of hydrogen stable isotopes (δ(2)H). A graphic representation of δ(13)C versus δ(2)H revealed that vanillin extracted from pods grown in adjacent geographic origins grouped together. Accordingly, values of δ(13)C and δ(2)H can be used for studies of authenticity and traceability of vanilla flavors.

  20. Stable Isotope Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Tissue samples (skin, bone, blood, muscle) are analyzed for stable carbon, stable nitrogen, and stable sulfur analysis. Many samples are used in their entirety for...

  1. An Ocean Sediment Core-Top Calibration of Foraminiferal (Cibicides) Stable Carbon Isotope Ratios

    Science.gov (United States)

    Schmittner, A.; Mix, A. C.; Lisiecki, L. E.; Peterson, C.; Mackensen, A.; Cartapanis, O. A.

    2015-12-01

    Stable carbon isotope ratios (δ13C) measured on calcium carbonate shells of benthic foraminifera (cibicides) from late Holocene sediments (δ13CCib) are compiled and compared with newly updated datasets of contemporary water-column δ13C observations of dissolved inorganic carbon (δ13CDIC) as the initial core-top calibration of the international Ocean Circulation and CarbonCycling (OC3) project. Using selection criteria based on the spatial distance between samples we find high correlation between δ13CCib and natural (pre-industrial) δ13CDIC, confirming earlier work. However, our analysis reveals systematic differences such as higher (lower) δ13CCib values in the Atlantic (Indian and Pacific) oceans. Regression analyses are impacted by anthropogenic carbon and suggest significant carbonate ion, temperature, and pressure effects, consistent with lab experiments with planktonic foraminifera and theory. The estimated standard error of core-top sediment data is generally σ ~= 0.25 ‰, whereas modern foram data from the South Atlantic indicate larger errors (σ ~= 0.4 ‰).

  2. A versatile method for simultaneous stable carbon isotope analysis of DNA and RNA nucleotides by liquid chromatography/isotope ratio mass spectrometry

    NARCIS (Netherlands)

    Moerdijk-Poortvliet, T.C.W.; Brasser, J.; de Ruiter, G.; Houtekamer, M.; Bolhuis, H.; Stal, L.J.; Boschker, H.T.S.

    2014-01-01

    RATIONALELiquid chromatography/isotope ratio mass spectrometry (LC/IRMS) is currently the most accurate and precise technique for the measurement of compound-specific stable carbon isotope ratios (C-13/C-12) in biological metabolites, at their natural abundance. However, until now this technique

  3. Determination of the origin of dissolved inorganic carbon in groundwater around a reclaimed landfill in Otwock using stable carbon isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Porowska, Dorota, E-mail: dorotap@uw.edu.pl

    2015-05-15

    Highlights: • Research showed the origin of DIC in the groundwater around a reclaimed landfill. • Carbon isotope was used to evaluate the contributions of carbon from different sources. • The leachate-contaminated water was isotopically distinct from the natural groundwater. • DIC in the natural groundwater comes from organic matter and dissolution of carbonates. • In the contaminated water, DIC comes from organic matter in the aquifer and landfill. - Abstract: Chemical and isotopic analyses of groundwater from piezometers located around a reclaimed landfill in Otwock (Poland) were performed in order to trace the origin of dissolved inorganic carbon (DIC) in the groundwater. Due to differences in the isotopic composition of carbon from different sources, an analysis of stable carbon isotopes in the groundwater, together with the Keeling plot approach and a two-component mixing model allow us to evaluate the relative contributions of carbon from these sources in the groundwater. In the natural (background) groundwater, DIC concentrations and the isotopic composition of DIC (δ{sup 13}C{sub DIC}) comes from two sources: decomposition of organic matter and carbonate dissolution within the aquifer sediments, whereas in the leachate-contaminated groundwater, DIC concentrations and δ{sup 13}C{sub DIC} values depend on the degradation of organic matter within the aquifer sediments and biodegradation of organic matter stored in the landfill. From the mixing model, about 4–54% of the DIC pool is derived from organic matter degradation and 96–46% from carbonate dissolution in natural conditions. In the leachate-contaminated groundwater, about 20–53% of the DIC is derived from organic matter degradation of natural origin and 80–47% from biodegradation of organic matter stored in the landfill. Partial pressure of CO{sub 2} (P CO{sub 2}) was generally above the atmospheric, hence atmospheric CO{sub 2} as a source of carbon in DIC pool was negligible in the

  4. Determination of the origin of dissolved inorganic carbon in groundwater around a reclaimed landfill in Otwock using stable carbon isotopes.

    Science.gov (United States)

    Porowska, Dorota

    2015-05-01

    Chemical and isotopic analyses of groundwater from piezometers located around a reclaimed landfill in Otwock (Poland) were performed in order to trace the origin of dissolved inorganic carbon (DIC) in the groundwater. Due to differences in the isotopic composition of carbon from different sources, an analysis of stable carbon isotopes in the groundwater, together with the Keeling plot approach and a two-component mixing model allow us to evaluate the relative contributions of carbon from these sources in the groundwater. In the natural (background) groundwater, DIC concentrations and the isotopic composition of DIC (δ(13)CDIC) comes from two sources: decomposition of organic matter and carbonate dissolution within the aquifer sediments, whereas in the leachate-contaminated groundwater, DIC concentrations and δ(13)CDIC values depend on the degradation of organic matter within the aquifer sediments and biodegradation of organic matter stored in the landfill. From the mixing model, about 4-54% of the DIC pool is derived from organic matter degradation and 96-46% from carbonate dissolution in natural conditions. In the leachate-contaminated groundwater, about 20-53% of the DIC is derived from organic matter degradation of natural origin and 80-47% from biodegradation of organic matter stored in the landfill. Partial pressure of CO2 (P CO2) was generally above the atmospheric, hence atmospheric CO2 as a source of carbon in DIC pool was negligible in the aquifer. P CO2 values in the aquifer in Otwock were always one to two orders of magnitude above the atmospheric P CO2, and thus CO2 escaped directly into the vadose zone. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Carbon allocation belowground in Pinus pinaster using stable carbon isotope pulse labeling technique

    Science.gov (United States)

    Dannoura, M.; Bosc, A.; Chipeaux, C.; Sartore, M.; Lambrot, C.; Trichet, P.; Bakker, M.; Loustau, D.; Epron, D.

    2010-12-01

    Carbon allocation belowground competes with aboveground growth and biomass production. In the other hand, it contributes to resource acquisition such as nutrient, water and carbon sequestration in soil. Thus, a better characterization of carbon flow from plant to soil and its residence time within each compartment is an important issue for understanding and modeling forest ecosystem carbon budget. 13C pulse labeling of whole crown was conducted at 4 seasons to study the fate of assimilated carbon by photosynthesis into the root on 12 year old Pinus pinaster planted in the INRA domain of Pierroton. Maritime pine is the most widely planted species in South-West Europe. Stem, root and soil CO2 effluxes and their isotope composition were measured continuously by tunable diode laser absorption spectroscopy with a trace gas analyzer (TGA 100A; Campbell Scientific) coupled to flow-through chambers. 13CO2 recovery and peak were observed in respiration of each compartment after labeling. It appeared sequentially from top of stem to bottom, and to coarse root. The maximum velocity of carbon transfer was calculated as the difference in time lag of recovery between two positions on the trunk or on the root. It ranged between 0.08-0.2 m h-1 in stem and between 0.04-0.12 m h-1 in coarse root. This velocity was higher in warmer season, and the difference between time lag of recovery and peak increased after first frost. Photosynthates arrived underground 1.5 to 5 days after labeling, at similar time in soil CO2 effluxes and coarse root respiration. 0.08-1.4 g of carbon was respired per tree during first 20 days following labeling. It presented 0.6 -10% of 13C used for labeling and it is strongly related to seasons. The isotope signal was detected in fine root organs and microbial biomass by periodical core sampling. The peak was observed 6 days after labeling in early summer while it was delayed more than 10 days in autumn and winter with less amount of carbon allocated

  6. Stable carbon isotope signals in particulate organic and inorganic carbon of coccolithophores - A numerical model study for Emiliania huxleyi.

    Science.gov (United States)

    Holtz, Lena-Maria; Wolf-Gladrow, Dieter; Thoms, Silke

    2017-05-07

    A recent numerical cell model, which explains observed light and carbonate system effects on particulate organic and inorganic carbon (POC and PIC) production rates under the assumption of internal pH homeostasis, is extended for stable carbon isotopes ( 12 C, 13 C). Aim of the present study is to mechanistically understand the stable carbon isotopic fractionation signal (ε) in POC and PIC and furthermore the vital effect(s) included in measured ε PIC values. The virtual cell is divided into four compartments, for each of which the 12 C as well as the 13 C carbonate system kinetics are implemented. The compartments are connected to each other via trans-membrane fluxes. In contrast to existing carbon fractionation models, the presented model calculates the disequilibrium state for both carbonate systems and for each compartment. It furthermore calculates POC and PIC production rates as well as ε POC and ε PIC as a function of given light conditions and the compositions of the external carbonate system. Measured POC and PIC production rates as well as ε PIC values are reproduced well by the model (comparison with literature data). The observed light effect on ε POC (increase of ε POC with increasing light intensities), however, is not reproduced by the basic model set-up, which is solely based on RubisCO fractionation. When extending the latter set-up by assuming that biological fractionation includes further carbon fractionation steps besides the one of RubisCO, the observed light effect on ε POC is also reproduced. By means of the extended model version, four different vital effects that superimpose each other in a real cell can be detected. Finally, we discuss potential limitations of the ε PIC proxy. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Uses of stable isotopes

    International Nuclear Information System (INIS)

    Axente, Damian

    1998-01-01

    The most important fields of stable isotope use with examples are presented. These are: 1. Isotope dilution analysis: trace analysis, measurements of volumes and masses; 2. Stable isotopes as tracers: transport phenomena, environmental studies, agricultural research, authentication of products and objects, archaeometry, studies of reaction mechanisms, structure and function determination of complex biological entities, studies of metabolism, breath test for diagnostic; 3. Isotope equilibrium effects: measurement of equilibrium effects, investigation of equilibrium conditions, mechanism of drug action, study of natural processes, water cycle, temperature measurements; 4. Stable isotope for advanced nuclear reactors: uranium nitride with 15 N as nuclear fuel, 157 Gd for reactor control. In spite of some difficulties of stable isotope use, particularly related to the analytical techniques, which are slow and expensive, the number of papers reporting on this subject is steadily growing as well as the number of scientific meetings organized by International Isotope Section and IAEA, Gordon Conferences, and regional meeting in Germany, France, etc. Stable isotope application development on large scale is determined by improving their production technologies as well as those of labeled compound and the analytical techniques. (author)

  8. Inorganic markers, carbonaceous components and stable carbon isotope from biomass burning aerosols in northeast China

    Science.gov (United States)

    Cao, F.; Zhang, Y.; Kawamura, K.

    2015-12-01

    To better characterize the sources of fine particulate matter (i.e. PM2.5) in Sanjiang Plain, Northeast China, aerosol chemical composition such total carbon (TC), organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), and inorganic ions were studied as well as stable carbon isotopic composition (δ13C) of TC. Intensively open biomass burning episodes were identified from late September to early October by satellite fire and aerosol optical depth maps. During the biomass burning episodes, concentrations of PM2.5, OC, EC, and WSOC increased by a factor of 4-12 compared to non-biomass-burning periods. Non-sea-salt potassium is strongly correlated with PM2.5, OC, EC and WSOC, suggesting an important contribution of biomass burning emission. The enrichment in both the non-sea-salt potassium and chlorine is significantly larger than other inorganic species, indicating that biomass burning aerosols in Sanjiang Plain is mostly fresh and less aged. In addition, WSOC to OC ratio is relatively lower compared to that reported in biomass burning aerosols in tropical regions, supporting that biomass burning aerosols in Sanjiang Plain is mostly primary and secondary organic aerosols is not significant. A lower average δ13C value (-26.2‰) is found for the biomass-burning aerosols, suggesting a dominant contribution from combustion of C3 plants in the studied region.

  9. Preliminary Study: Application of Off-Axis ICOS to Determine Stable Carbon Isotope in Dissolved Inorganic Carbon

    Science.gov (United States)

    Kim, Y. T.; Lee, J. M.; Hwang, J. H.; Piao, J.; Woo, N. C.

    2015-12-01

    CO2 is one of the major causes for global climate change. Because stable carbon isotope ratio is used to trace carbon source, several analytical techniques likes IRMS (Isotope Ratio Mass Spectrometry) and LAS (Laser Absorption Spectrometry) were extensively used. Off-axis ICOS, a kind of LAS, has merits on long-term stability and field application, therefore it is widely being used in CCS (Carbon Capture and Storage) field. The aim of this study is to extend the application scope of OA-ICOS to determine dissolved inorganic carbon (DIC). Because OA-ICOS showed dependence of δ13C on CO2 concentration, data processing is required. We tested CO2 Carbon Isotope Analyzer (CCIA-36-EP, Los Gatos Research) with both reference gas (δ13C= -28.28‰) and aqueous solutions prepared by dissolving sodium bicarbonate standards (δ13C= -12.26‰ and +3.96‰). The differences of δ13C between reference and measurement values are plotted by CO2 concentrations, then compared. At first, we checked the similarity between our curve pattern for reference gas and Guillon's research (δ13C= -43.99‰) by other Analyzer. To analyze aqueous samples, more errors can be caused than gas analysis. The carbon isotope fractionation occurs during dissolving standard reagents and extracting DIC as CO2 gas form. This effect is mixed with CO2 concentration dependence effect, therefore the curve patterns are different with that for reference gas. Our experiments are done for various δ13C values. It could be an important point to use OA-ICOS to analyze DIC, too.

  10. Carbon and Nitrogen Stable Isotope Values for Plants and Mammals in a Semi-Desert Region of Mongolia

    Directory of Open Access Journals (Sweden)

    Hannah Davie

    2014-12-01

    Full Text Available Little information exists on the isotopic signatures of plants and animals in Mongolia, limiting the application of stable isotope analysis to wildlife biology studies. Here we present plant and mammal carbon (δ 13 C and nitrogen (δ 15 N isotope values from a desert-steppe region of southeastern Mongolia. We analyzed 11 samples from 11 plant species and 93 samples from 24 mammal species across Ikh Nart Nature Reserve, and compared these numbers to isotope values reported from other areas of Mongolia. Our plant and mammal 13 C and 15 N values were similar to those from a similar arid steppe region and more enriched than those from less arid habitats. Habitat variation within and between study sites has an important infl uence on δ 13 C and δ 15 N variation. Our results supplement current knowledge of isotopic variation in Mongolia and provide a reference for future stable isotope research in Mongolia and similar Asian steppe ecosystems.

  11. Monitoring trichloroethene remediation at an iron permeable reactive barrier using stable carbon isotopic analysis

    Science.gov (United States)

    VanStone, Nancy; Przepiora, Andrzej; Vogan, John; Lacrampe-Couloume, Georges; Powers, Brian; Perez, Ernesto; Mabury, Scott; Sherwood Lollar, Barbara

    2005-08-01

    Stable carbon isotopic analysis, in combination with compositional analysis, was used to evaluate the performance of an iron permeable reactive barrier (PRB) for the remediation of ground water contaminated with trichloroethene (TCE) at Spill Site 7 (SS7), F.E. Warren Air Force Base, Wyoming. Compositional data indicated that although the PRB appeared to be reducing TCE to concentrations below treatment goals within and immediately downgradient of the PRB, concentrations remained higher than expected at wells further downgradient (i.e. > 9 m) of the PRB. At two wells downgradient of the PRB, TCE concentrations were comparable to upgradient values, and δ13C values of TCE at these wells were not significantly different than upgradient values. Since the process of sorption/desorption does not significantly fractionate carbon isotope values, this suggests that the TCE observed at these wells is desorbing from local aquifer materials and was present before the PRB was installed. In contrast, three other downgradient wells show significantly more enriched δ13C values compared to the upgradient mean. In addition, δ13C values for the degradation products of TCE, cis-dichloroethene and vinyl chloride, show fractionation patterns expected for the products of the reductive dechlorination of TCE. Since concentrations of both TCE and degradation products drop to below detection limit in wells within the PRB and directly below it, these downgradient chlorinated hydrocarbon concentrations are attributed to desorption from local aquifer material. The carbon isotope values indicate that this dissolved contaminant is subject to local degradation, likely due to in situ microbial activity.

  12. Monitoring trichloroethene remediation at an iron permeable reactive barrier using stable carbon isotopic analysis.

    Science.gov (United States)

    VanStone, Nancy; Przepiora, Andrzej; Vogan, John; Lacrampe-Couloume, Georges; Powers, Brian; Perez, Ernesto; Mabury, Scott; Sherwood Lollar, Barbara

    2005-08-01

    Stable carbon isotopic analysis, in combination with compositional analysis, was used to evaluate the performance of an iron permeable reactive barrier (PRB) for the remediation of ground water contaminated with trichloroethene (TCE) at Spill Site 7 (SS7), F.E. Warren Air Force Base, Wyoming. Compositional data indicated that although the PRB appeared to be reducing TCE to concentrations below treatment goals within and immediately downgradient of the PRB, concentrations remained higher than expected at wells further downgradient (i.e. >9 m) of the PRB. At two wells downgradient of the PRB, TCE concentrations were comparable to upgradient values, and delta13C values of TCE at these wells were not significantly different than upgradient values. Since the process of sorption/desorption does not significantly fractionate carbon isotope values, this suggests that the TCE observed at these wells is desorbing from local aquifer materials and was present before the PRB was installed. In contrast, three other downgradient wells show significantly more enriched delta13C values compared to the upgradient mean. In addition, delta13C values for the degradation products of TCE, cis-dichloroethene and vinyl chloride, show fractionation patterns expected for the products of the reductive dechlorination of TCE. Since concentrations of both TCE and degradation products drop to below detection limit in wells within the PRB and directly below it, these downgradient chlorinated hydrocarbon concentrations are attributed to desorption from local aquifer material. The carbon isotope values indicate that this dissolved contaminant is subject to local degradation, likely due to in situ microbial activity.

  13. Radiocarbon and stable-isotope geochemistry of organic and inorganic carbon in Lake Superior

    Science.gov (United States)

    Zigah, Prosper K.; Minor, Elizabeth C.; Werne, Josef P.

    2012-03-01

    We present a lake-wide investigation of Lake Superior carbon and organic matter biogeochemistry using radiocarbon, stable isotope, and carbon concentrations. Dissolved inorganic carbon (DIC) abundance in the lake was 121-122 Tg C, with offshore concentration andδ13C values being laterally homogenous and tightly coupled to the physical and thermal regime and biochemical processes. Offshore Δ14C of DIC (50-65‰) exhibited lateral homogeneity and was more 14C enriched than co-occurring atmospheric CO2 (˜38‰); nearshore Δ14C of DIC (36-38‰) was similar to atmospheric CO2. Dissolved organic carbon (DOC) abundance was 14.2-16.4 Tg C. DOC's concentration and δ13C were homogenous in June (mixed lake), but varied laterally during August (stratification) possibly due to spatial differences in lake productivity. Throughout sampling, DOC had modern radiocarbon values (14-58‰) indicating a semilabile nature with a turnover time of ≤60 years. Lake particulate organic carbon (POC, 0.9-1.3 Tg C) was consistently 13C depleted relative to DOC. The δ15N of epilimnetic particulate organic nitrogen shifted to more negative values during stratification possibly indicating greater use of nitrate (rather than ammonium) by phytoplankton in August. POC's radiocarbon was spatially heterogeneous (Δ14C range: 58‰ to -303‰), and generally 14C depleted relative to DOC and DIC. POC 14C depletion could not be accounted for by black carbon in the lake but, because of its spatial and temporal distribution, is attributed to sediment resuspension. The presence of old POC within the epilimnion of the open lake indicates possible benthic-pelagic coupling in the lake's organic carbon cycle; the ultimate fate of this old POC bears further investigation.

  14. The effects of early diagenesis on the chemical and stable carbon isotopic composition of wood

    International Nuclear Information System (INIS)

    Spiker, E.C.; Hatcher, P.G.

    1987-01-01

    Studies of modern and ancient buried wood show that there is a linear correlation between carbohydrate content and the stable carbon isotope composition as carbohydrates are preferentially degraded during early diagenesis. As the carbohydrate content decreases, the delta 13 C value of the degraded wood decreases 1 to 2 per mil, approaching the value of the residual lignin. These results indicate that carbohydrate degradation products are lost and not incorporated into the aromatic structure as lignin is selectively preserved during early diagenesis of wood. These results also indicate that attempts to quantify terrestrial inputs to modern sedimentary organic matter based on delta 13 C values should consider the possibility of a 1 to 2 per mil decrease in the delta 13 C value of degraded wood. (author)

  15. Organic geochemistry and stable isotope composition of New Zealand carbonate concretions and calcite fracture fills

    International Nuclear Information System (INIS)

    Pearson, M.J.; Nelson, C.S.

    2005-01-01

    Carbonate concretion bodies, representing a number of morphological types, and associated calcite fracture fills, mainly from New Zealand, have been studied both organically and inorganically. Extracted organic material is dominated by a complex polymeric dark brown highly polar fraction with a subordinate less polar and lighter coloured lipid fraction. The relative proportion of the two fractions is the principal control on the colour of fracture fill calcites. Concretions are classified mainly by reference to their carbonate stable carbon and oxygen isotope and cation composition. Typical subspherical calcitic septarian concretions, such as those in the Paleocene Moeraki and the Eocene Rotowaro Siltstones, contain carbon derived mainly by bacterial sulfate reduction in marine strata during early diagenesis. Other concretions, including a septarian calcitic type from the Northland Allochthon, have a later diagenetic origin. Siderite concretions, abundant in the nonmarine Waikato Coal Measures, are typically dominated by methanogenic carbon, whereas paramoudra-like structures from the Taranaki Miocene have the most extreme carbon isotope compositions, probably resulting from methane formation or oxidation in fluid escape conduits. Lipids from concretion bodies and most fracture fill calcites contain significant concentrations of fatty acids. Concretion bodies dominated by bimodally distributed n-fatty acids with strong even-over-odd preference, in which long chain n-acids are of terrestrial origin, have very low hydrocarbon biomarker maturities. Concretion bodies that lack long chain n-acids often have higher apparent biomarker maturity and prominent alpha-omega diacids. Such diacids are abundant in fracture fill calcites at Rotowaro, especially where calcite infills the septaria of a siderite concretion in the non-marine Waikato Coal Measures, and support the view that fluid transport resulted in carbonate entrapment of the fracture-hosted acids. Diacids also

  16. Stable isotopes of pedogenic carbonates from the Somma-Vesuvius area, southern Italy, over the past 18 kyr: palaeoclimatic implications

    Science.gov (United States)

    Zanchetta, G.; di Vito, M.; Fallick, A. E.; Sulpizio, R.

    2000-12-01

    Stable isotopes were measured in the carbonate and organic matter of palaeosols in the Somma-Vesuvius area, southern Italy in order to test whether they are suitable proxy records for climatic and ecological changes in this area during the past 18000 yr. The ages of the soils span from ca. 18 to ca. 3 kyr BP. Surprisingly, the Last Glacial to Holocene climate transition was not accompanied by significant change in 18O of pedogenic carbonate. This could be explained by changes in evaporation rate and in isotope fractionation between water and precipitated carbonate with temperature, which counterbalanced the expected change in isotope composition of meteoric water. Because of the rise in temperature and humidity and the progressive increase in tree cover during the Holocene, the Holocene soil carbonates closely reflect the isotopic composition of meteoric water. A cooling of about 2°C after the Avellino eruption (3.8 ka) accounts for a sudden decrease of about 1 in 18O of pedogenic carbonate recorded after this eruption. The 13C values of organic matter and pedogenic carbonate covary, indicating an effective isotope equilibrium between the organic matter, as the source of CO2, and the pedogenic carbonate. Carbon isotopes suggest prevailing C3 vegetation and negligible mixing with volcanogenic or atmospheric CO2.

  17. Stable carbon isotope fractionation in pollen of Atlas cedar: first steps towards a new palaeoecological proxy for Northwest Africa

    Science.gov (United States)

    Bell, Benjamin; Fletcher, William; Ryan, Peter; Grant, Helen; Ilmen, Rachid

    2016-04-01

    Analysis of stable carbon isotopes can provide information on climate and the environmental conditions at different growth stages of the plant, both past and present. Carbon isotope discrimination in plant tissue is already well understood, and can be used as a drought stress indicator for semi-arid regions. Stable carbon isotope ratios measured directly on pollen provides the potential for the development of long-term environmental proxies (spanning thousands of years), as pollen is well preserved in the environment. Atlas Cedar (Cedrus atlantica Endl. Manetti ex Carrière), is an ideal test case to develop a pollen stable carbon isotope proxy. The tree grows across a wide altitudinal and climatic range and is extremely sensitive to moisture availability. The pollen is abundant, and easily identifiable to the species level in pollen analysis because different cedar species are geographically confined to different regions of the world. In 2015 we sampled 76 individual cedar trees across latitudinal, altitudinal and environmental gradients, highly focused on the Middle Atlas region of Morocco, with 25 additional samples from botanical gardens across Europe and the US to extend these gradients. Here, we report new stable carbon isotope data from pollen, leaf and stem wood from these samples with a view to assessing and quantifying species-specific fractionation effects associated with pollen production. The isotopic response of individual trees at local and wider geographical scales to altitude and climatic conditions is presented. This research forms part of an ongoing PhD project working to develop and calibrate a modern carbon isotope proxy in Atlas cedar pollen, which can ultimately be applied to fossil sequences and complement existing multi-proxy records (e.g. pollen analysis in lake sediments, tree-rings).

  18. Calcium stable isotope geochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Gausonne, Nikolaus [Muenster Univ. (Germany). Inst. fuer Mineralogie; Schmitt, Anne-Desiree [Strasbourg Univ. (France). LHyGeS/EOST; Heuser, Alexander [Bonn Univ. (Germany). Steinmann-Inst. fuer Geologie, Mineralogie und Palaeontologie; Wombacher, Frank [Koeln Univ. (Germany). Inst. fuer Geologie und Mineralogie; Dietzel, Martin [Technische Univ. Graz (Austria). Inst. fuer Angewandte Geowissenschaften; Tipper, Edward [Cambridge Univ. (United Kingdom). Dept. of Earth Sciences; Schiller, Martin [Copenhagen Univ. (Denmark). Natural History Museum of Denmark

    2016-08-01

    This book provides an overview of the fundamentals and reference values for Ca stable isotope research, as well as current analytical methodologies including detailed instructions for sample preparation and isotope analysis. As such, it introduces readers to the different fields of application, including low-temperature mineral precipitation and biomineralisation, Earth surface processes and global cycling, high-temperature processes and cosmochemistry, and lastly human studies and biomedical applications. The current state of the art in these major areas is discussed, and open questions and possible future directions are identified. In terms of its depth and coverage, the current work extends and complements the previous reviews of Ca stable isotope geochemistry, addressing the needs of graduate students and advanced researchers who want to familiarize themselves with Ca stable isotope research.

  19. Calcium stable isotope geochemistry

    International Nuclear Information System (INIS)

    Gausonne, Nikolaus; Schmitt, Anne-Desiree; Heuser, Alexander; Wombacher, Frank; Dietzel, Martin; Tipper, Edward; Schiller, Martin

    2016-01-01

    This book provides an overview of the fundamentals and reference values for Ca stable isotope research, as well as current analytical methodologies including detailed instructions for sample preparation and isotope analysis. As such, it introduces readers to the different fields of application, including low-temperature mineral precipitation and biomineralisation, Earth surface processes and global cycling, high-temperature processes and cosmochemistry, and lastly human studies and biomedical applications. The current state of the art in these major areas is discussed, and open questions and possible future directions are identified. In terms of its depth and coverage, the current work extends and complements the previous reviews of Ca stable isotope geochemistry, addressing the needs of graduate students and advanced researchers who want to familiarize themselves with Ca stable isotope research.

  20. Assessing dissolved carbon transport and transformation along an estuarine river with stable isotope analyses

    Science.gov (United States)

    He, Songjie; Xu, Y. Jun

    2017-10-01

    Estuaries play an important role in the dynamics of dissolved carbon from rivers to coastal oceans. However, our knowledge of dissolved carbon transport and transformation in mixing zones of the world's coastal rivers is still limited. This study aims to determine how dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC) concentrations and stable isotopes (δ13CDIC and δ13CDOC) change along an 88-km long estuarine river, the Calcasieu River in Louisiana, southern USA, with salinity ranging from 0.02 to 21.92. The study is expected to elucidate which processes most likely control carbon dynamics in a freshwater-saltwater mixing system, and to evaluate the net metabolism of this estuary. Between May 2015 and February 2016, water samples were collected and in-situ measurements on ambient water conditions were performed during five field trips at six sites from upstream to downstream of the Calcasieu River, which enters the Northern Gulf of Mexico (NGOM). The DIC concentration and δ13CDIC increased rapidly with increasing salinity in the mixing zone. The average DIC concentration and δ13CDIC at the site closest to the NGOM (site 6) were 1.31 mM and -6.34‰, respectively, much higher than those at the site furthest upstream (site 1, 0.42 mM and -20.83‰). The DIC concentrations appeared to be largely influenced by conservative mixing, while high water temperature may have played a role in deviating DIC concentration from the conservative line due likely to increased respiration and decomposition. The δ13CDIC values were close to those suggested by the conservative mixing model for May, June and November, but lower than those for July and February, suggesting that an estuarine river can fluctuate from a balanced to a heterotrophic system (i.e., production/respiration (P/R) aquatic photosynthesis from carbon produced by terrestrial photosynthesis in a river-ocean continuum.

  1. Carbon and Hydrogen Stable Isotope Fractionation during Aerobic Bacterial Degradation of Aromatic Hydrocarbons†

    Science.gov (United States)

    Morasch, Barbara; Richnow, Hans H.; Schink, Bernhard; Vieth, Andrea; Meckenstock, Rainer U.

    2002-01-01

    13C/12C and D/H stable isotope fractionation during aerobic degradation was determined for Pseudomonas putida strain mt-2, Pseudomonas putida strain F1, Ralstonia pickettii strain PKO1, and Pseudomonas putida strain NCIB 9816 grown with toluene, xylenes, and naphthalene. Different types of initial reactions used by the respective bacterial strains could be linked with certain extents of stable isotope fractionation during substrate degradation. PMID:12324375

  2. Stable isotopes - separation and application

    International Nuclear Information System (INIS)

    Lockhart, I.M.

    1980-01-01

    In this review, methods used for the separation of stable isotopes ( 12 C, 13 C, 14 N, 15 N, 16 O, 17 O, 18 O, 34 S) will be described. The synthesis of labelled compounds, techniques for detection and assay, and areas of application will also be discussed. Particular attention will be paid to the isotopes of carbon, nitrogen, and oxygen; to date, sulphur isotopes have only assumed a minor role. The field of deuterium chemistry is too extensive for adequate treatment; it will therefore be essentially excluded. (author)

  3. Optimizing sample pretreatment for compound-specific stable carbon isotopic analysis of amino sugars in marine sediment

    Science.gov (United States)

    Zhu, R.; Lin, Y.-S.; Lipp, J. S.; Meador, T. B.; Hinrichs, K.-U.

    2014-09-01

    Amino sugars are quantitatively significant constituents of soil and marine sediment, but their sources and turnover in environmental samples remain poorly understood. The stable carbon isotopic composition of amino sugars can provide information on the lifestyles of their source organisms and can be monitored during incubations with labeled substrates to estimate the turnover rates of microbial populations. However, until now, such investigation has been carried out only with soil samples, partly because of the much lower abundance of amino sugars in marine environments. We therefore optimized a procedure for compound-specific isotopic analysis of amino sugars in marine sediment, employing gas chromatography-isotope ratio mass spectrometry. The whole procedure consisted of hydrolysis, neutralization, enrichment, and derivatization of amino sugars. Except for the derivatization step, the protocol introduced negligible isotopic fractionation, and the minimum requirement of amino sugar for isotopic analysis was 20 ng, i.e., equivalent to ~8 ng of amino sugar carbon. Compound-specific stable carbon isotopic analysis of amino sugars obtained from marine sediment extracts indicated that glucosamine and galactosamine were mainly derived from organic detritus, whereas muramic acid showed isotopic imprints from indigenous bacterial activities. The δ13C analysis of amino sugars provides a valuable addition to the biomarker-based characterization of microbial metabolism in the deep marine biosphere, which so far has been lipid oriented and biased towards the detection of archaeal signals.

  4. Comparison of stable carbon isotope ratios in the whole wood, cellulose and lignin of Oak tree-rings

    CSIR Research Space (South Africa)

    Loader, NJ

    2003-08-01

    Full Text Available The stable carbon isotope ratios (N13C) of whole wood, cellulose and acid-insoluble lignin from annual latewood increments of Quereus robur L., from modern and sub-fossil wood, were measured and their potential use as palaeo environmental indicators...

  5. Carbon-13 conundrums: limitations and cautions in the use of stable isotope analysis in stream ecotonal research

    International Nuclear Information System (INIS)

    France, R.L.

    1996-01-01

    A secondary analysis of literature was compiled and performed on the δ 13 C values for allochthonous litter, attached algae and consumers in stream ecosystems, finding that 'existing data conflict as to the capability of stable isotope analysis (SIA) for distinguishing carbon pathways'. The paper is in defence of the work previously performed and suggests caution when using stream SIA research. 48 refs

  6. Carbon and nitrogen stable isotope ratios of pelagic zooplankton elucidate ecohydrographic features in the oligotrophic Red Sea

    KAUST Repository

    Kü rten, Benjamin; Al-Aidaroos, Ali M.; Kurten, Saskia; El-Sherbiny, Mohsen M.; Devassy, Reny P.; Struck, Ulrich; Zarokanellos, Nikolaos; Jones, Burton; Hansen, Thomas; Bruss, Gerd; Sommer, Ulrich

    2015-01-01

    Although zooplankton occupy key roles in aquatic biogeochemical cycles, little is known about the pelagic food web and trophodynamics of zooplankton in the Red Sea. Natural abundance stable isotope analysis (SIA) of carbon (δ13C) and N (δ15N) is one

  7. Stable carbon isotope analysis reveals widespread drought stress in boreal black spruce forests.

    Science.gov (United States)

    Walker, Xanthe J; Mack, Michelle C; Johnstone, Jill F

    2015-08-01

    Unprecedented rates of climate warming over the past century have resulted in increased forest stress and mortality worldwide. Decreased tree growth in association with increasing temperatures is generally accepted as a signal of temperature-induced drought stress. However, variations in tree growth alone do not reveal the physiological mechanisms behind recent changes in tree growth. Examining stable carbon isotope composition of tree rings in addition to tree growth can provide a secondary line of evidence for physiological drought stress. In this study, we examined patterns of black spruce growth and carbon isotopic composition in tree rings in response to climate warming and drying in the boreal forest of interior Alaska. We examined trees at three nested scales: landscape, toposequence, and a subsample of trees within the toposequence. At each scale, we studied the potential effects of differences in microclimate and moisture availability by sampling on northern and southern aspects. We found that black spruce radial growth responded negatively to monthly metrics of temperature at all examined scales, and we examined ∆(13)C responses on a subsample of trees as representative of the wider region. The negative ∆(13)C responses to temperature reveal that black spruce trees are experiencing moisture stress on both northern and southern aspects. Contrary to our expectations, ∆(13)C from trees on the northern aspect exhibited the strongest drought signal. Our results highlight the prominence of drought stress in the boreal forest of interior Alaska. We conclude that if temperatures continue to warm, we can expect drought-induced productivity declines across large regions of the boreal forest, even for trees located in cool and moist landscape positions. © 2015 John Wiley & Sons Ltd.

  8. Stable carbon and oxygen isotope signatures in molluscan shells under ocean acidification

    Science.gov (United States)

    Nishida, K.; Hayashi, M.; Suzuki, A.; Sato, M.; Nojiri, Y.

    2017-12-01

    Stable carbon and oxygen isotope compositions (δ13C, δ18O) of biogenic carbonate have been widely used for many paleoclimate, paleoecological, and biomineralization studies. δ13C of molluscan shells reflects the mixing of δ13C of dissolved inorganic carbon (DIC) of seawater and respiratory carbon. Previous studies reported physiological effects on molluscs by ocean acidification, and thus the metabolic changes could potentially appear in shell δ13C as changes in a fraction of two carbon sources. In addition, shell δ18O, a commonly used proxy of seawater temperature and seawater δ18O, is also affected by seawater carbonate chemistry. As changes in the marine carbonate system, such as pH and pCO2, have occurred in the past 300 million years, to estimate pH effect on paleotemperature reconstruction is important. Here, we experimentally examined acidification effects on shell δ13C and δ18O of two species of clams for understanding of environmental and physiological proxies. Juvenile specimens of bloody clam Scapharca broughtonii and Japanese surf clam Pseudocardium sachalinense were cultured at five (400, 600, 800, 1000, and 1200 µatm, P. sachalinense) or six (280, 400, 600, 800, 1000, and 1200 µatm, S. broughtonii) different pCO2 levels using CO2 control system of the Demonstration Laboratory, MERI, Japan. Significant negative correlations between shell δ13C and pH appeared in S. broughtonii, which showed non-significant pH effects on calcification, and the slope of the relationship of shell carbonate was lower than that of seawater DIC. On the other hand, in P. sachalinense which showed a decrease in calcification at low-pH treatment, the slopes of the relationship between shell δ13C and pH was roughly the same as that of seawater DIC. Thus, the extrapallial fluid of P. sachalinense might more strongly affected by acidified seawater than S. broughtonii. The results of two species might be attributable to differences in physiological responses to

  9. Online stable carbon isotope ratio measurement in formic acid, acetic acid, methanol and ethanol in water by high performance liquid chromatography-isotope ratio mass spectrometry

    International Nuclear Information System (INIS)

    Tagami, Keiko; Uchida, Shigeo

    2008-01-01

    A suitable analysis condition was determined for high performance liquid chromatography-isotope ratio mass spectrometry (HPLC-IRMS) while making sequential measurements of stable carbon isotope ratios of δ 13 C in formic acid, acetic acid, methanol and ethanol dissolved in water. For this online column separation method, organic reagents are not applicable due to carbon contamination; thus, water and KH 2 PO 4 at low concentrations were tested as mobile phase in combination with a HyPURITY AQUASTAR TM column. Formic acid, acetic acid, methanol and ethanol were separated when 2 mM KH 2 PO 4 aqueous solution was used. Under the determined analysis condition for HPLC-IRMS, carbon concentrations could be measured quantitatively as well as carbon isotope ratio when carbon concentration was higher than 0.4 mM L for each chemical

  10. Stable isotopes of carbon and nitrogen as markers of dietary variation among sociocultural subgroups of Inuit in Greenland.

    Science.gov (United States)

    Bjerregaard, Peter; Larsen, Christina V L; Dahl-Petersen, Inger K; Buchardt, Bjørn

    2017-09-10

    We assessed the use of stable isotopes of carbon and nitrogen as biomarkers for traditional versus store-bought food among the Inuit. Furthermore, we compared the isotope patterns among sociocultural population groups. As a part of a country-wide health survey in Greenland during 2005-2010, we analyzed the isotope composition of toenails from 1025 adult Inuit and meat of common species hunted for food. Information on diet and sociocultural variables was collected by interviews. Weighted by sex and place of residence to the total population of Inuit in Greenland, the average δ 13 C value in toenails was -20.2‰ and the δ 15 N value was 12.0‰ which are higher than in a general Danish omnivorous population. Both isotopes were significantly associated with other biomarkers of marine food and with results of a Food Frequency Questionnaire (FFQ). The percentage of marine food in the diet was estimated at 21% from the mean δ 13 C value, 25% from the mean δ 15 N value, and 23% from the FFQ. Nail samples for analysis of stable isotopes of carbon and nitrogen were convenient to collect during a large population health survey among the Inuit. Isotope enrichment levels showed statistically significant associations with other biomarkers for consumption of marine food and with results of an FFQ and were used to estimate the percentage of marine food in the diet. Isotope levels were significantly associated with a novel score of sociocultural transition. © 2017 Wiley Periodicals, Inc.

  11. Annual and seasonal distribution of intertidal foraminifera and stable carbon isotope geochemistry, Bandon Marsh, Oregon, USA

    Science.gov (United States)

    Milker, Yvonne; Horton, Benjamin; Vane, Christopher; Engelhart, Simon; Nelson, Alan R.; Witter, Robert C.; Khan, Nicole S.; Bridgeland, William

    2014-01-01

    We investigated the influence of inter-annual and seasonal differences on the distribution of live and dead foraminifera, and the inter-annual variability of stable carbon isotopes (d13C), total organic carbon (TOC) values and carbon to nitrogen (C/N) ratios in bulk sediments from intertidal environments of Bandon Marsh (Oregon, USA). Living and dead foraminiferal species from 10 stations were analyzed over two successive years in the summer (dry) and fall (wet) seasons. There were insignificant inter-annual and seasonal variations in the distribution of live and dead species. But there was a noticeable decrease in calcareous assemblages (Haynesina sp.) between live populations and dead assemblages, indicating that most of the calcareous tests were dissolved after burial; the agglutinated assemblages were comparable between constituents. The live populations and dead assemblages were dominated by Miliammina fusca in the tidal flat and low marsh, Jadammina macrescens, Trochammina inflata and M. fusca in the high marsh, and Trochamminita irregularis and Balticammina pseudomacrescens in the highest marsh to upland. Geochemical analyses (d13C, TOC and C/N of bulk sedimentary organic matter) show no significant influence of inter-annual variations but a significant correlation of d13C values (R = 20.820, p , 0.001), TOC values (R = 0.849, p , 0.001) and C/N ratios (R = 0.885, p , 0.001) to elevation with respect to the tidal frame. Our results suggest that foraminiferal assemblages and d13C and TOC values, as well as C/N ratios, in Bandon Marsh are useful in reconstructing paleosea-levels on the North American Pacific coast.

  12. Studying biosphere-atmosphere exchange of CO2 through Carbon-13 stable isotopes

    NARCIS (Netherlands)

    Velde, van der I.R.

    2015-01-01

    Summary Thesis ‘Studying biosphere-atmosphere exchange of CO2 through

    carbon-13 stable isotopes’

    Ivar van der Velde

    Making predictions of future climate is difficult, mainly due to large uncertainties in the carbon cycle. The rate at which carbon is stored in the oceans and

  13. Tracing carbon flow through coral reef food webs using a compound-specific stable isotope approach.

    Science.gov (United States)

    McMahon, Kelton W; Thorrold, Simon R; Houghton, Leah A; Berumen, Michael L

    2016-03-01

    Coral reefs support spectacularly productive and diverse communities in tropical and sub-tropical waters throughout the world's oceans. Debate continues, however, on the degree to which reef biomass is supported by new water column production, benthic primary production, and recycled detrital carbon (C). We coupled compound-specific stable C isotope ratio (δ(13)C) analyses with Bayesian mixing models to quantify C flow from primary producers to coral reef fishes across multiple feeding guilds and trophic positions in the Red Sea. Analyses of reef fishes with putative diets composed primarily of zooplankton (Amblyglyphidodon indicus), benthic macroalgae (Stegastes nigricans), reef-associated detritus (Ctenochaetus striatus), and coral tissue (Chaetodon trifascialis) confirmed that δ(13)C values of essential amino acids from all baseline C sources were both isotopically diagnostic and accurately recorded in consumer tissues. While all four source end-members contributed to the production of coral reef fishes in our study, a single-source end-member often dominated dietary C assimilation of a given species, even for highly mobile, generalist top predators. Microbially reworked detritus was an important secondary C source for most species. Seascape configuration played an important role in structuring resource utilization patterns. For instance, Lutjanus ehrenbergii showed a significant shift from a benthic macroalgal food web on shelf reefs (71 ± 13 % of dietary C) to a phytoplankton-based food web (72 ± 11 %) on oceanic reefs. Our work provides insights into the roles that diverse C sources play in the structure and function of coral reef ecosystems and illustrates a powerful fingerprinting method to develop and test nutritional frameworks for understanding resource utilization.

  14. Tracing carbon flow through coral reef food webs using a compound-specific stable isotope approach

    KAUST Repository

    McMahon, Kelton

    2015-11-21

    Coral reefs support spectacularly productive and diverse communities in tropical and sub-tropical waters throughout the world’s oceans. Debate continues, however, on the degree to which reef biomass is supported by new water column production, benthic primary production, and recycled detrital carbon (C). We coupled compound-specific stable C isotope ratio (δ13C) analyses with Bayesian mixing models to quantify C flow from primary producers to coral reef fishes across multiple feeding guilds and trophic positions in the Red Sea. Analyses of reef fishes with putative diets composed primarily of zooplankton (Amblyglyphidodon indicus), benthic macroalgae (Stegastes nigricans), reef-associated detritus (Ctenochaetus striatus), and coral tissue (Chaetodon trifascialis) confirmed that δ13C values of essential amino acids from all baseline C sources were both isotopically diagnostic and accurately recorded in consumer tissues. While all four source end-members contributed to the production of coral reef fishes in our study, a single-source end-member often dominated dietary C assimilation of a given species, even for highly mobile, generalist top predators. Microbially reworked detritus was an important secondary C source for most species. Seascape configuration played an important role in structuring resource utilization patterns. For instance, Lutjanus ehrenbergii showed a significant shift from a benthic macroalgal food web on shelf reefs (71 ± 13 % of dietary C) to a phytoplankton-based food web (72 ± 11 %) on oceanic reefs. Our work provides insights into the roles that diverse C sources play in the structure and function of coral reef ecosystems and illustrates a powerful fingerprinting method to develop and test nutritional frameworks for understanding resource utilization.

  15. Stable carbon isotope analyses of nanogram quantities of particulate organic carbon (pollen) with laser ablation nano combustion gas chromatography/isotope ratio mass spectrometry

    Science.gov (United States)

    Sluijs, Appy; Laks, Jelmer J.; Reichart, Gert‐Jan

    2016-01-01

    Rationale Analyses of stable carbon isotope ratios (δ 13C values) of organic and inorganic matter remains have been instrumental for much of our understanding of present and past environmental and biological processes. Until recently, the analytical window of such analyses has been limited to samples containing at least several μg of carbon. Methods Here we present a setup combining laser ablation, nano combustion gas chromatography and isotope ratio mass spectrometry (LA/nC/GC/IRMS). A deep UV (193 nm) laser is used for optimal fragmentation of organic matter with minimum fractionation effects and an exceptionally small ablation chamber and combustion oven are used to reduce the minimum sample mass requirement compared with previous studies. Results Analyses of the international IAEA CH‐7 polyethylene standard show optimal accuracy, and precision better than 0.5‰, when measuring at least 42 ng C. Application to untreated modern Eucalyptus globulus (C3 plant) and Zea mays (C4 plant) pollen grains shows a ~ 16‰ offset between these species. Within each single Z. mays pollen grain, replicate analyses show almost identical δ 13C values. Conclusions Isotopic offsets between individual pollen grains exceed analytical uncertainties, therefore probably reflecting interspecimen variability of ~0.5–0.9‰. These promising results set the stage for investigating both δ 13C values and natural carbon isotopic variability between single specimens of a single population of all kinds of organic particles yielding tens of nanograms of carbon. © 2016 The Authors. Rapid Communications in Mass Spectrometry Published by John Wiley & Sons Ltd. PMID:27766694

  16. Carbon Monoxide Stable Isotopes: Extraction Technique Development and Urban Atmospheric Analysis

    Science.gov (United States)

    Vimont, Isaac Josef

    We have developed an extraction system to analyze isotopes of carbon monoxide (CO). We then analyzed CO isotopes for two years at Indianapolis, IN, USA. These measurements were done at three towers, one of which measured incoming, background air into the city. We quantitatively removed the background signal and determined the urban CO mole fraction and isotopic enhancements. During the winter months, we constrained the isotopic signature and concluded that the majority of CO produced during the winter was produced by fossil fuel combustion. We found that the Indianapolis fossil fuel signature differed from that of studies done in Europe. Further, we performed a limited traffic study to look at CO isotopes from traffic. While this was not conclusive, it did support our hypothesis that a larger fraction of the Indianapolis vehicle fleet may have malfunctioning catalytic systems, which biases the isotopic results, particularly for delta18O. We used the wintertime fossil fuel isotopic signature to help constrain the summertime budget. It was hypothesized that a second source of CO was significant during the summer months. Oxidation of biogenically produced volatile organic compounds (BVOC's) was one possible source. Oxidized BVOC's were consistent with the changes between our winter and summer isotopic source signatures. We then used the isotopic signatures to determine that between zero and sixty percent of the summertime CO budget was produced from oxidized VOC's. This provided the first direct evidence of a larger percentage of urban CO being produced by oxidized VOC's.

  17. Assessment of Bacterial Degradation of Aromatic Hydrocarbons in the Environment by Analysis of Stable Carbon Isotope Fractionation

    Energy Technology Data Exchange (ETDEWEB)

    Meckenstock, Rainer U. [Eberhard-Karls University of Tuebingen, Center for Applied Geoscience (Germany)], E-mail: rainer.meckenstock@uni-tuebingen.de; Morasch, Barbara [University of Konstanz, Faculty of Biology (Germany); Kaestner, Matthias; Vieth, Andrea; Richnow, Hans Hermann [Center for Environmental Research, Department of Remediation Research (Germany)

    2002-05-15

    {sup 13}C/{sup 12}C stable carbon isotope fractionation was used to assess biodegradation in contaminated aquifers with toluene as a model compound. Different strains of anaerobic bacteria (Thauera aromatica, Geobacter metallireducens, and the sulfate-reducing strain TRM1) showed consistent {sup 13}C/{sup 12}C carbon isotope fractionation with fractionation factors between {alpha}C = 1.0017 and 1.0018. In contrast, three cultures of aerobic organisms, using different mono- and dioxygenase enzyme systems to initiate toluene degradation, showed variable isotope fractionation factors of {alpha}C = 1.0027 (Pseudomonasputida strain mt-2), {alpha}C = 1.0011 (Ralstonia picketii), and{alpha}C = 1.0004 (Pseudomonas putida strain F1). The great variability of isotope fractionation between different aerobic bacterial strains suggests that interpretation of isotope data in oxic habitats can only be qualitative. A soil column was run as a model system for contaminated aquifers with toluene as the carbon source and sulfate as the electron acceptor and samples were taken at different ports along the column. Microbial toluene degradation was calculated based on the {sup 13}C/{sup 12}C isotope fractionation factors of the batch culture experiments together with the observed {sup 13}C/{sup 12}C isotope shifts of the residual toluene fractions. The calculated percentage of biodegradation, B, correlated well with the decreasing toluene concentrations at the sampling ports and indicated the increasing extent of biodegradation along the column. The theoretical toluene concentrations as calculated based on the isotope values matched the measured concentrations at the different sampling ports indicating that the Rayleigh equation can be used to calculate biodegradation in quasi closed systems based on measured isotope shifts. A similar attempt was performed to assess toluene degradation in a contaminated, anoxic aquifer. A transect of groundwater wells was monitored along the main

  18. Assessment of Bacterial Degradation of Aromatic Hydrocarbons in the Environment by Analysis of Stable Carbon Isotope Fractionation

    International Nuclear Information System (INIS)

    Meckenstock, Rainer U.; Morasch, Barbara; Kaestner, Matthias; Vieth, Andrea; Richnow, Hans Hermann

    2002-01-01

    13 C/ 12 C stable carbon isotope fractionation was used to assess biodegradation in contaminated aquifers with toluene as a model compound. Different strains of anaerobic bacteria (Thauera aromatica, Geobacter metallireducens, and the sulfate-reducing strain TRM1) showed consistent 13 C/ 12 C carbon isotope fractionation with fractionation factors between αC = 1.0017 and 1.0018. In contrast, three cultures of aerobic organisms, using different mono- and dioxygenase enzyme systems to initiate toluene degradation, showed variable isotope fractionation factors of αC = 1.0027 (Pseudomonasputida strain mt-2), αC = 1.0011 (Ralstonia picketii), andαC = 1.0004 (Pseudomonas putida strain F1). The great variability of isotope fractionation between different aerobic bacterial strains suggests that interpretation of isotope data in oxic habitats can only be qualitative. A soil column was run as a model system for contaminated aquifers with toluene as the carbon source and sulfate as the electron acceptor and samples were taken at different ports along the column. Microbial toluene degradation was calculated based on the 13 C/ 12 C isotope fractionation factors of the batch culture experiments together with the observed 13 C/ 12 C isotope shifts of the residual toluene fractions. The calculated percentage of biodegradation, B, correlated well with the decreasing toluene concentrations at the sampling ports and indicated the increasing extent of biodegradation along the column. The theoretical toluene concentrations as calculated based on the isotope values matched the measured concentrations at the different sampling ports indicating that the Rayleigh equation can be used to calculate biodegradation in quasi closed systems based on measured isotope shifts. A similar attempt was performed to assess toluene degradation in a contaminated, anoxic aquifer. A transect of groundwater wells was monitored along the main direction of the groundwater flow and revealed decreasing

  19. Carbon and oxygen stable isotope and trace element studies in speleothems and across the J-K boundary, Central Italy

    International Nuclear Information System (INIS)

    Kudielka, G.

    2001-07-01

    Carbon and Oxygen stable isotope ratios of carbonates decisively depend on fractionation during physicochemical processes. Therefore, they represent a powerful tool to derive information on past conditions under which the carbonates formed. Isotope ratio mass spectrometry (IRMS) offers a large range of applications. This thesis presents two projects based upon investigation of carbon and oxygen stable isotope ratios combined with trace element abundances (determined by instrumental neutron activation analysis, INAA) in carbonates. (1) Palaeoclimatic investigation on speleothems from central Italy. Four speleothems from Grotta Grande del Vento, central Italy, were analyzed for stable isotope ratios and trace element abundances, and age dated to obtain a chronologically reliable stable isotope profile. The speleothems were sampled by means of a dental drill to gain a stable isotope profile with a 0.5 mm resolution, trace element abundances have been performed by INAA every 0.5 cm, and the samples for age dating were picked according to remarkable features in the stable isotope trends and analyzed by TIMS. The record covers the period from 93 ka until the early holocene with a hiatus lasting from 75 ka until 65.0 ka. Speleothem growth during the last glacial indicates moderate conditions in the Frasassi region back then. Comparison with speleothems from Ireland, France and northern Italy reveal a north-south slope in d18O, indicating, that the rain over central Italy mainly originates from the North Atlantic. Depletion of moisture in d18O during its continental trajectory is due to rainout, which primarily extracts the heavy isotopes. The stable isotope record is in good agreement with the high-resolution speleothem record from Soreq Cave, Israel. Distinct isotopic events coincide between 85 ka and 80 ka, between ∼ 60 ka and 50 ka and from the last glacial to the early holocene. An offset has been existing between the two records at any time. The speleothems of

  20. Disentangling drought-induced variation in ecosystem and soil respiration using stable carbon isotopes.

    Science.gov (United States)

    Unger, Stephan; Máguas, Cristina; Pereira, João S; Aires, Luis M; David, Teresa S; Werner, Christiane

    2010-08-01

    Combining C flux measurements with information on their isotopic composition can yield a process-based understanding of ecosystem C dynamics. We studied the variations in both respiratory fluxes and their stable C isotopic compositions (delta(13)C) for all major components (trees, understory, roots and soil microorganisms) in a Mediterranean oak savannah during a period with increasing drought. We found large drought-induced and diurnal dynamics in isotopic compositions of soil, root and foliage respiration (delta(13)C(res)). Soil respiration was the largest contributor to ecosystem respiration (R (eco)), exhibiting a depleted isotopic signature and no marked variations with increasing drought, similar to ecosystem respired delta(13)CO(2), providing evidence for a stable C-source and minor influence of recent photosynthate from plants. Short-term and diurnal variations in delta(13)C(res) of foliage and roots (up to 8 and 4 per thousand, respectively) were in agreement with: (1) recent hypotheses on post-photosynthetic fractionation processes, (2) substrate changes with decreasing assimilation rates in combination with increased respiratory demand, and (3) decreased phosphoenolpyruvate carboxylase activity in drying roots, while altered photosynthetic discrimination was not responsible for the observed changes in delta(13)C(res). We applied a flux-based and an isotopic flux-based mass balance, yielding good agreement at the soil scale, while the isotopic mass balance at the ecosystem scale was not conserved. This was mainly caused by uncertainties in Keeling plot intercepts at the ecosystem scale due to small CO(2) gradients and large differences in delta(13)C(res) of the different component fluxes. Overall, stable isotopes provided valuable new insights into the drought-related variations of ecosystem C dynamics, encouraging future studies but also highlighting the need of improved methodology to disentangle short-term dynamics of isotopic composition of R (eco).

  1. Forensic Stable Isotope Biogeochemistry

    Science.gov (United States)

    Cerling, Thure E.; Barnette, Janet E.; Bowen, Gabriel J.; Chesson, Lesley A.; Ehleringer, James R.; Remien, Christopher H.; Shea, Patrick; Tipple, Brett J.; West, Jason B.

    2016-06-01

    Stable isotopes are being used for forensic science studies, with applications to both natural and manufactured products. In this review we discuss how scientific evidence can be used in the legal context and where the scientific progress of hypothesis revisions can be in tension with the legal expectations of widely used methods for measurements. Although this review is written in the context of US law, many of the considerations of scientific reproducibility and acceptance of relevant scientific data span other legal systems that might apply different legal principles and therefore reach different conclusions. Stable isotopes are used in legal situations for comparing samples for authenticity or evidentiary considerations, in understanding trade patterns of illegal materials, and in understanding the origins of unknown decedents. Isotope evidence is particularly useful when considered in the broad framework of physiochemical processes and in recognizing regional to global patterns found in many materials, including foods and food products, drugs, and humans. Stable isotopes considered in the larger spatial context add an important dimension to forensic science.

  2. Analytical system for stable carbon isotope measurements of low molecular weight (C2-C6 hydrocarbons

    Directory of Open Access Journals (Sweden)

    T. Röckmann

    2011-06-01

    Full Text Available We present setup, testing and initial results from a new automated system for stable carbon isotope ratio measurements on C2 to C6 atmospheric hydrocarbons. The inlet system allows analysis of trace gases from air samples ranging from a few liters for urban samples and samples with high mixing ratios, to many tens of liters for samples from remote unpolluted regions with very low mixing ratios. The centerpiece of the sample preparation is the separation trap, which is used to separate CO2 and methane from the compounds of interest. The main features of the system are (i the capability to sample up to 300 l of air, (ii long term (since May 2009 operational δ13C accuracy levels in the range 0.3–0.8 ‰ (1-σ, and (iii detection limits of order 1.5–2.5 ngC (collected amount of substance for all reported compounds. The first application of this system was the analysis of 21 ambient air samples taken during 48 h in August 2009 in Utrecht, the Netherlands. Results obtained are generally in good agreement with those from similar urban ambient air studies. Short sample intervals allowed by the design of the instrument help to illustrate the complex diurnal behavior of hydrocarbons in an urban environment, where diverse sources, dynamical processes, and chemical reactions are present.

  3. Use of carbon stable isotope to investigate chloromethane formation in the electrolytic dechlorination of trichloroethylene

    International Nuclear Information System (INIS)

    Fang Yuanxiang; Al-Abed, Souhail R.

    2007-01-01

    Carbon stable isotope trichloroethylene ( 13 C TCE) was used to investigate the formation of chloromethane (CM) during the electrolytic dechlorination of trichloroethylene (TCE) at a granular-graphite packed cathode. A method was developed to use a conventional GC/MS to analyze and quantify regular and 13 C TCE and their dechlorination products. The concentration of a 13 C compound can be calculated, based on the concentration of its regular counterpart, from the response ratio of two fragments of different mass per charge values from the compounds in a sample and two characteristic MS spectrum ratios: one is the response ratio of the two fragments of the regular compound, and the other is the response ratio of the corresponding fragments of the regular and 13 C compounds at the same concentrations. The method was used to analyze the regular and 13 C compounds observed in an experiment of dechlorination in an ammonium acetate solution that contained both regular TCE and 13 C TCE. Results of analysis confirmed that CM was not a direct product of TCE dechlorination at the granular graphite cathode that cis-DCE was an intermediate product of TCE dechlorination, and that 1,1-DCE was not a dechlorination product

  4. Use of carbon stable isotope to investigate chloromethane formation in the electrolytic dechlorination of trichloroethylene

    Energy Technology Data Exchange (ETDEWEB)

    Fang Yuanxiang [National Risk Management Research Laboratory, USEPA 26 W. Martin Luther King Dr. Cincinnati, OH 45268 (United States); Al-Abed, Souhail R. [National Risk Management Research Laboratory, USEPA 26 W. Martin Luther King Dr. Cincinnati, OH 45268 (United States)]. E-mail: Al-Abed.Souhail@epa.gov

    2007-03-22

    Carbon stable isotope trichloroethylene ({sup 13}C TCE) was used to investigate the formation of chloromethane (CM) during the electrolytic dechlorination of trichloroethylene (TCE) at a granular-graphite packed cathode. A method was developed to use a conventional GC/MS to analyze and quantify regular and {sup 13}C TCE and their dechlorination products. The concentration of a {sup 13}C compound can be calculated, based on the concentration of its regular counterpart, from the response ratio of two fragments of different mass per charge values from the compounds in a sample and two characteristic MS spectrum ratios: one is the response ratio of the two fragments of the regular compound, and the other is the response ratio of the corresponding fragments of the regular and {sup 13}C compounds at the same concentrations. The method was used to analyze the regular and {sup 13}C compounds observed in an experiment of dechlorination in an ammonium acetate solution that contained both regular TCE and {sup 13}C TCE. Results of analysis confirmed that CM was not a direct product of TCE dechlorination at the granular graphite cathode that cis-DCE was an intermediate product of TCE dechlorination, and that 1,1-DCE was not a dechlorination product.

  5. Carbon and Nitrogen Stable Isotopes in Fastfood: Signatures of Corn and Confinement

    Science.gov (United States)

    Jahren, H.; Kraft, R.

    2008-12-01

    Americans spend more than one hundred billion dollars on restaurant fastfood each year; fastfood meals comprise a disproportionate amount of both meat and calories within the U.S. diet. Frustrated by futile attempts to gain information about the origin and production of fastfood from the companies themselves, we used carbon and nitrogen stable isotopes to infer the source of feed to meat animals, the source of fat within fries, and the extent of fertilization and confinement inherent to production. We sampled food from McDonald's, Burger King and Wendy's chains, purchasing more than 480 servings of hamburgers, chicken sandwiches and fries within geographically-distributed U.S. cities: Los Angeles, San Francisco, Denver, Detroit, Boston and Baltimore. From the entire sample set of beef and chicken, only 12 servings of beef had δ13C McDonald's and Burger King favored other vegetable oils; this differed from ingredient reports. Our results highlighted the overwhelming importance of corn agriculture within virtually every aspect of fastfood manufacture.

  6. Simulation and optimization of stable isotope 13C separation by carbon monoxide cryogenic distillation

    International Nuclear Information System (INIS)

    Li Hulin; Ju Yonglin; Li Liangjun; Xu Dagang

    2009-01-01

    A stable isotope 13 C separation column was set up by carbon monoxide (CO) cryogenic distillation. Diameter of the column is 45 mm, packing height is 17.5 m, of which enriching section is 15 m and stripping section is 2.5 m. Firstly, computer simulation results were validated by test results. Secondly, tests were replaced by computer simulations in order to obtain the optimal operation conditions in the experimental setup. Comprehensive factors of column pressure, feeding velocity, reflux ratio, withdrawing velocity, and boiling power impacts on the products were studied. Then optimization design of the experimental device was achieved through computer simulations combined with uniform experimental design. The final results show that the optimal operation conditions in the built column are as followings: boiling power, 250 W; column pressure, 54 kPa; reflux ratio, 84. The conclusion is that the method of combination of computer simulation and experimental design could be applied to 13 C industrial design and could be popularized in traditional distillation process to realize optimization design. (authors)

  7. Long-term summer temperature variations in the Pyrenees from detrended stable carbon isotopes

    Czech Academy of Sciences Publication Activity Database

    Esper, J.; Konter, O.; Krusic, P. J.; Saurer, M.; Holzkaemper, S.; Büntgen, Ulf

    2015-01-01

    Roč. 42, č. 1 (2015), s. 53-59 ISSN 1897-1695 Institutional support: RVO:67179843 Keywords : tree-rings * climate sensitivity * past millennium * delta-o-18 * delta-c-13 * cellulose * wood * uncertainties * chronologies * variability * Climate change * paleoclimatology * stable isotope geochemistry * tree-rings * Europe Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 2.038, year: 2015

  8. Using Stable Isotopes of Carbon and Nitrogen to Evaluate Trophic Interactions in Aquatic Environments

    Science.gov (United States)

    Christensen, David R.; LaRoche, Andrew

    2012-01-01

    This paper describes a series of laboratory exercises for upper level biology courses, independent research and/or honors programs. Students sampled fish from a local water body with the assistance of a local fish and wildlife agency. Tissue samples from collected fish were utilized to obtain estimates of the stable isotopes delta[superscript 13]C…

  9. Influence of organic carbon sources and isotope exchange processes between water and nitrate on the fractionation of the stable isotopes 15N/14N and 18O/16O in dissolved nitrate during microbial dentrification in groundwater

    International Nuclear Information System (INIS)

    Wunderlich, Anja A.L.

    2012-01-01

    Stable isotopes of nitrate are commonly used to determine sources and degradation of nitrate. In this study, nitrite oxidizing bacteria were found to promote an oxygen isotope exchange between water and nitrate under anoxic conditions. Also, different carbon sources were found to influence the enrichment of stable isotopes in nitrate during microbial denitrification. Both results refine the stable isotope model of nitrate in respect to nitrate source determination and microbial nitrate reduction.

  10. Stable isotope analysis

    International Nuclear Information System (INIS)

    Tibari, Elghali; Taous, Fouad; Marah, Hamid

    2014-01-01

    This report presents results related to stable isotopes analysis carried out at the CNESTEN DASTE in Rabat (Morocco), on behalf of Senegal. These analyzes cover 127 samples. These results demonstrate that Oxygen-18 and Deuterium in water analysis were performed by infrared Laser spectroscopy using a LGR / DLT-100 with Autosampler. Also, the results are expressed in δ values (‰) relative to V-SMOW to ± 0.3 ‰ for oxygen-18 and ± 1 ‰ for deuterium.

  11. Mass spectrometric analysis of stable carbon isotopes in abiogenic and biogenic natural compounds

    International Nuclear Information System (INIS)

    Sajjad, M.I.; Ahmed, M.; Tasneem, M.A.; Khan, I.A.; Latif, Z.

    1989-07-01

    This report describes the general methodology of sup/13/ carbon analysis on mass spectrometer and various preparation systems developed for conversion of samples into isotopically non-fractionated and purified carbon dioxide. Laboratory standards required for sup/13/ C analysis have been calibrated against international standards. The reproducibility/accuracy of sample preparation and analysis on mass spectrometer for sup/13/ C or sup/12/ C measurement is well within the internationally acceptable limits. (author)

  12. Assessing diet in savanna herbivores using stable carbon isotope ratios of faeces

    Directory of Open Access Journals (Sweden)

    D. Codron

    2005-06-01

    Full Text Available In African savannas, browse-based resources (@3 plants are isotopically distinct from grasses (@4 plants. The carbon isotopic composition of the basic plant diet is recorded in animal tissues. Mammal faeces are a readily accessible, non-invasive, sample material for temporally resolved dietary reconstructions. Faeces, however, include both undigested plant matter and waste, hence accuracy of dietary calculations could potentially be compromised by shifts in plant isotopic values related to seasonal or spatial differences, or by variability in the isotopic differences between faeces and diet. A controlled feeding study of four ungulate species showed a small, consistent difference between diet and faeces of-0.9 o, irrespective of whether the diet was @3 or C4-based. Results from faeces oftaxa known to be pure grazers, pure browsers, and mixed-feeders from the Kruger National Park were entirely consistent with their diets, but the accuracy of dietary reconstructions is enhanced with data from local plant communities.

  13. Variation in stable carbon isotopes in organic matter from the Gunflint Iron Formation

    International Nuclear Information System (INIS)

    Barghoorn, E.S.; Knoll, A.H.; Dembicki, H. Jr.; Meinschein, W.G.

    1977-01-01

    In order to examine possible variations in organic carbon isotopic ratios within a single Precambrian formation, the kerogen separated from 15 samples of the approximately 2000 m.y. old Gunflint Iron Formation and the conformably overlying Rove Formation, representing a wide range of lithologies and geographic localities, was isotopically analyzed. From the resulting data, four conclusions can be drawn: (1) delta 13 C values of the shallow water algal chert facies are significantly more negative (-25 to -30 parts per thousand) than those of the deeper water chert-carbonate and taconite facies (-15 to -20 parts per thousand). Comparative data for modern marine algal mats shows a range of delta 13 C values from -8.4 to -19 parts per thousand PDB. Values obtained for fresh water mats were slightly more negative. (2) These differences in isotopic ratios can be correlated with similar differences in preserved microbiotas. (3) Anthraxolite lenses are depleted in 13 C relative to the reduced carbon in surrounding sediments. (4) The effect of Keweenawan diabase intrusions upon the carbon isotopic composition is pronounced, but limited to the immediate vicinity of the contact. (author)

  14. Normalization of stable isotope data for carbonate minerals: implementation of IUPAC guideline

    Science.gov (United States)

    Kim, Sang-Tae; Coplen, Tyler B.; Horita, Juske

    2015-01-01

    Carbonate minerals provide a rich source of geochemical information because their δ13C and δ18O values provide information about surface and subsurface Earth processes. However, a significant problem is that the same δ18O value is not reported for the identical carbonate sample when analyzed in different isotope laboratories in spite of the fact that the International Union of Pure and Applied Chemistry (IUPAC) has provided reporting guidelines for two decades. This issue arises because (1) the δ18O measurements are performed on CO2 evolved by reaction of carbonates with phosphoric acid, (2) the acid-liberated CO2 is isotopically fractionated (enriched in 18O) because it contains only two-thirds of the oxygen from the solid carbonate, (3) this oxygen isotopic fractionation factor is a function of mineralogy, temperature, concentration of the phosphoric acid, and δ18O value of water in the phosphoric acid, (4) researchers may use any one of an assortment of oxygen isotopic fractionation factors that have been published for various minerals at various reaction temperatures, and (5) it sometimes is not clear how one should calculate δ18OVPDB values on a scale normalized such that the δ18O value of SLAP reference water is −55.5 ‰ relative to VSMOW reference water.

  15. Relationship between climate and vegetation and the stable carbon isotope chemistry of soils in the eastern Mojave Desert, Nevada

    International Nuclear Information System (INIS)

    Amundson, R.G.; Chadwick, O.A.; Sowers, J.M.; Doner, H.E.

    1988-01-01

    The relationship between the stable C-isotope composition of the soil environment and modern climate and vegetation was determined empirically along a present-day climatic transect in the eastern Mojave Desert. The δ 13 C of the soil CO 2 and carbonates decreased with increasing elevation and plant density, even though plant assemblages at all elevations were isotopically similar. Several factors, including differences in the ratios of pedogenic of limestone calcite and differences in past vegetation, were considered as explanations of this trend, However, it appears that in the sparsely vegetated Mojave Desert, the δ 13 C of pedogenic carbonate is controlled by differences in plant density and biological activity. This relationship may provide a tool for assessing past vegetational densities, as long as the vegetation is isotopically homogeneous. (author)

  16. A novel high-temperature combustion based system for stable isotope analysis of dissolved organic carbon in aqueous samples. : I development and validation

    NARCIS (Netherlands)

    Federherr, E.; Cerli, C.; Kirkels, F. M. S. A.; Kalbitz, K.; Kupka, H. J.; Dunsbach, R.; Lange, L.; Schmidt, T. C.

    2014-01-01

    RATIONALE: Traditionally, dissolved organic carbon (DOC) stable isotope analysis (SIA) is performed using either offline sample preparation followed by elemental analyzer/isotope ratiomass spectrometry (EA/IRMS) or a wet chemical oxidation (WCO)-based device coupled to an isotope ratio mass

  17. Diagenetic evolution and stable isotopes of Lower Permian platform marginal carbonates (Trogkofel Limestone, Carnic Alps, Austria)

    Science.gov (United States)

    Schaffhauser, Maria; Krainer, Karl; Sanders, Diethard Gerald; Spötl, Christoph

    2010-05-01

    and filling of fractures. Closely below the erosional surface at the top of the Trogkofel Limestone, the dolomite is characterized by vuggy porosity. The Tarvis Breccia, which represents coarse alluvial fan deposits, in turn, is thick-bedded, poorly sorted, typically clast-supported, and consists of angular lithoclasts embedded in a matrix of former lime mudstone. Both, matrix as well as lithoclasts, are dolomitized. Various types of cement (isopachous, botryoidal, microbialite, calcite spar), karstic cavity fills (isopachous cements, internal sediments), and replacement dolomites of the Trogkofel section, as well as of the Tarvis Breccia were analysed for their stable isotopic composition. δ18O and δ13C data produced so far allow to differentiate between replacement dolomites and saddle dolomite of the Trogkofel Limestone and the Tarvis Breccia. Saddle dolomite shows the most depleted oxygen isotope values, suggesting formation during relatively high temperatures. Carbon isotope values are invariably positive in all dolomite types indicating lacking influence of organic diagenesis on the alkalinity of the deep-burial pore water. Matrix dolomite from the Tarvis Breccia shows slightly positive δ18O values. Calcite cements show a wide range in δ18O values (ca. -1 to -7 permil VPDB), which overlaps the composition of unaltered brachiopod shells (ca. -3 permil VPDB). Oxygen isotope values of calcite cements reveal a trend towards depleted δ18O values. This trend is reflecting most likely increasing temperature.

  18. Development of a Method to Isolate Glutamic Acid from Foodstuffs for a Precise Determination of Their Stable Carbon Isotope Ratio.

    Science.gov (United States)

    Kobayashi, Kazuhiro; Tanaka, Masaharu; Yatsukawa, Yoichi; Tanabe, Soichi; Tanaka, Mitsuru; Ohkouchi, Naohiko

    2018-01-01

    Recent growing health awareness is leading to increasingly conscious decisions by consumers regarding the production and traceability of food. Stable isotopic compositions provide useful information for tracing the origin of foodstuffs and processes of food production. Plants exhibit different ratios of stable carbon isotopes (δ 13 C) because they utilized different photosynthetic (carbon fixation) pathways and grow in various environments. The origins of glutamic acid in foodstuffs can be differentiated on the basis of these photosynthetic characteristics. Here, we have developed a method to isolate glutamic acid in foodstuffs for determining the δ 13 C value by elemental analyzer-isotope-ratio mass spectrometry (EA/IRMS) without unintended isotopic fractionation. Briefly, following acid-hydrolysis, samples were defatted and passed through activated carbon and a cation-exchange column. Then, glutamic acid was isolated using preparative HPLC. This method is applicable to measuring, with a low standard deviation, the δ 13 C values of glutamic acid from foodstuffs derived from C3 and C4 plants and marine algae.

  19. Springtime carbon emission episodes at the Gosan background site revealed by total carbon, stable carbon isotopic composition, and thermal characteristics of carbonaceous particles

    Directory of Open Access Journals (Sweden)

    J. Jung

    2011-11-01

    Full Text Available In order to investigate the emission of carbonaceous aerosols at the Gosan background super-site (33.17° N, 126.10° E in East Asia, total suspended particles (TSP were collected during spring of 2007 and 2008 and analyzed for particulate organic carbon, elemental carbon, total carbon (TC, total nitrogen (TN, and stable carbon isotopic composition (δ13C of TC. The stable carbon isotopic composition of TC (δ13CTC was found to be lowest during pollen emission episodes (range: −26.2‰ to −23.5‰, avg. −25.2 ± 0.9‰, approaching those of the airborne pollen (−28.0‰ collected at the Gosan site. Based on a carbon isotope mass balance equation, we found that ~42% of TC in the TSP samples during the pollen episodes was attributed to airborne pollen from Japanese cedar trees planted around tangerine farms in Jeju Island. A negative correlation between the citric acid-carbon/TC ratios and δ13CTC was obtained during the pollen episodes. These results suggest that citric acid emitted from tangerine fruit may be adsorbed on the airborne pollen and then transported to the Gosan site. Thermal evolution patterns of organic carbon during the pollen episodes were characterized by high OC evolution in the OC2 temperature step (450 °C. Since thermal evolution patterns of organic aerosols are highly influenced by their molecular weight, they can be used as additional information on the formation of secondary organic aerosols and the effect of aging of organic aerosols during the long-range atmospheric transport and sources of organic aerosols.

  20. Stratigraphy and stable isotope geochemistry of the carbonate sequence from the Paraguay belt

    International Nuclear Information System (INIS)

    Santos, Roberto Ventura.; Alvarenga, Carlos Jose Souza de; Dantas, Elton Luiz

    2001-01-01

    Two main Neoproterozoic carbonate sequences occur central Brazil both of which are stratiphicaly above glacial derived sediments. An older carbonate sequence occurs over the Sao Francisco Craton and in the surrounding folded belts (Rio Preto, Aracuai Ribeira and Brasilia). These carbonates overlie glacial diamictites that were related to the 'Sturtian' event dated between 0.7 and 0.9 Ga (Toulkeridis et al. 1999, Santos et al., 2000). A second carbonate sequence is described in the Paraguay Belt and postdated Vendian/Varegian glaciation sediments from the end of the Neoproterozoic. This glacial event has been reported in many studies concerning the Gondwana and the Laurentia supercontinent (Trompette, 1996; Condon and Prave, 2000; Myrow and Kaufman, 1999). In the Paraguay Belt the Vendian- Varangian glaciation rocks are characterized by a glaciomarine sequence, that occur at the border of the basin, and by glacial derived turbidites deposits, that occur in the deeper parts of the basin (Alvarenga and Trompette, 1992). Near the city of Corumba this glaciomarine sequence is overlaid by carbonate rocks containing Ediacaran-like fauna in which has been described Corumbella werneri and Cloudina Lucianoi (Hahn et al., 1982; Walde et al., 1982; Zaine and Fairchild, 1985; 1987). These carbonates have been interpreted as cap carbonates and the age of their fossils have been attributed to the Vendian Superior (590-545 MA) (Alvarenga and Trompette, 1992, Trompette 1996). Isotope stratigraphy studies have been widely used to study cap carbonate rocks that overlie Sturtian and Vendian- Varagian glaciogenic rocks. Stratigraphic correlation of these units is usually difficult because their lack fossils and there is no precise dating method that could be applied to these rocks. Hence, most studies concerning Neoproterozoic carbonates have concentrated on their stromatilites and microfossils content as well as on carbon isotope variations. In the present study, we present new carbon

  1. Stable isotope (C, O) and monovalent cation fractionation upon synthesis of carbonate-bearing hydroxyl apatite (CHAP) via calcite transformation

    Science.gov (United States)

    Böttcher, Michael E.; Schmiedinger, Iris; Wacker, Ulrike; Conrad, Anika C.; Grathoff, Georg; Schmidt, Burkhard; Bahlo, Rainer; Gehlken, Peer-L.; Fiebig, Jens

    2016-04-01

    Carbonate-bearing hydroxyl-apatite (CHAP) is of fundamental and applied interest to the (bio)geochemical, paleontological, medical and material science communities, since it forms the basic mineral phase in human and animal teeth and bones. In addition, it is found in non-biogenic phosphate deposits. The stable isotope and foreign element composition of biogenic CHAP is widely used to estimate the formation conditions. This requires careful experimental calibration under well-defined boundary conditions. Within the DFG project EXCALIBOR, synthesis of carbonate-bearing hydroxyapatite was conducted via the transformation of synthetic calcite powder in aqueous solution as a function of time, pH, and temperature using batch-type experiments. The aqueous solution was analyzed for the carbon isotope composition of dissolved inorganic carbonate (gas irmMS), the oxygen isotope composition of water (LCRDS), and the cationic composition. The solid was characterized by powder X-ray diffraction, micro Raman and FTIR spectroscopy, SEM-EDX, elemental analysis (EA, ICP-OES) and gas irmMS. Temperature was found to significantly impact the transformation rate of calcite to CHAP. Upon complete transformation, CHAP was found to contain up to 5% dwt carbonate, depending on the solution composition (e.g., pH), both incorporated on the A and B type position of the crystal lattice. The oxygen isotope fractionation between water and CHAP decreased with increasing temperature with a tentative slope shallower than those reported in the literature for apatite, calcite or aragonite. In addition, the presence of dissolved NH4+, K+ or Na+ in aqueous solution led to partial incorporation into the CHAP lattice. How these distortions of the crystal lattice may impact stable isotope discrimination is subject of future investigations.

  2. Martian Cryogenic Carbonate Formation: Stable Isotope Variations Observed in Laboratory Studies

    Science.gov (United States)

    Socki, Richard A.; Niles, Paul B.; Sun, Tao; Fu, Qi; Romanek, Christopher S.; Gibson, Everett K. Jr.

    2014-01-01

    The history of water on Mars is tied to the formation of carbonates through atmospheric CO2 and its control of the climate history of the planet. Carbonate mineral formation under modern martian atmospheric conditions could be a critical factor in controlling the martian climate in a means similar to the rock weathering cycle on Earth. The combination of evidence for liquid water on the martian surface and cold surface conditions suggest fluid freezing could be very common on the surface of Mars. Cryogenic calcite forms easily from freezing solutions when carbon dioxide degasses quickly from Ca-bicarbonate-rich water, a process that has been observed in some terrestrial settings such as arctic permafrost cave deposits, lake beds of the Dry Valleys of Antarctica, and in aufeis (river icings) from rivers of N.E. Alaska. A series of laboratory experiments were conducted that simulated cryogenic carbonate formation on Mars in order to understand their isotopic systematics. The results indicate that carbonates grown under martian conditions show variable enrichments from starting bicarbonate fluids in both carbon and oxygen isotopes beyond equilibrium values.

  3. Stable carbon and oxygen isotope studies of Late Weichselian lake sediments in southern Sweden and northern Poland, with palaeoclimatic implications

    International Nuclear Information System (INIS)

    Hammarlund, D.

    1994-04-01

    Late Weichselian lacustrine sediment sequences from southern Sweden and northern Poland were studied by means of stable isotope analysis in order to reconstruct the climatic development and climatically induced environmental changes in the respective regions. The methods used include analyses of the stable carbon isotope composition (δ 13 C) of bulk organic material, and the stable carbon and oxygen isotope compositions (δ 13 C, δ 18 O) of bulk carbonates and carbonate shells of aquatic organisms. These results were complemented and supported by lithological, chemical and biostratigraphic data (plant macrofossils, insects, molluscs). Chronological data were obtained by AMS radiocarbon dates and correlations based on pollen analysis. At c. 12.400 BP a climatic change from arctic, dry, and continental, to subarctic and more humid and maritime conditions occurred in southern Sweden. The Older Dryas stadial (c.12.200-12.000 BP) is characterized by a temporary return to generally colder , drier, and more continental conditions, followed by generally favourable (subarctic), although unstable, climatic conditions. At c. 11.300 BP a gradual transition towards a colder and more continental climate was initiated, followed by total absence of limnic carbonates during the Younger Dryas stadial (c. 11.000-10.200 BP), indicating arctic and continental conditions. The transition to the Holocene is characterized by a rapid and strong climatic warming. The results from northern Poland point to some important differences compared to this development. A climatic warming around 13.000 BP was followed by generally favourable climatic conditions enabling continuous sedimentation of limnic carbonates during the Late Weichselian. Distinct depletions of 13 C in lacustrine organic material at the transition to the Holocene were recorded in southern Sweden, also demonstrated by decreasing mean values obtained from an extensive compilation of δ 13 C data. A number of processes that may

  4. Carbon Stable Isotope Values in Plankton and Mussels Reflect Changes in Carbonate Chemistry Associated with Nutrient Enhanced Net Production

    Directory of Open Access Journals (Sweden)

    Autumn Oczkowski

    2018-02-01

    Full Text Available Coastal ecosystems are inherently complex and potentially adaptive as they respond to changes in nutrient loads and climate. We documented the role that carbon stable isotope (δ13C measurements could play in understanding that adaptation with a series of three Ecostat (i.e., continuous culture experiments. We quantified linkages among δ13C, nutrients, carbonate chemistry, primary, and secondary production in temperate estuarine waters. Experimental culture vessels (9.1 L containing 33% whole and 67% filtered (0.2 μm seawater were amended with dissolved inorganic nitrogen (N and phosphorous (P in low (3 vessels; 5 μM N, 0.3 μM P, moderate (3 vessels; 25 μM N, 1.6 μM P, and high amounts (3 vessels; 50 μM N, 3.1 μM P. The parameters necessary to calculate carbonate chemistry, chlorophyll-a concentrations, and particulate δ13C values were measured throughout the 14 day experiments. Outflow lines from the experimental vessels fed 250 ml containers seeded with juvenile blue mussels (Mytilus edulis. Mussel subsamples were harvested on days 0, 7, and 14 and their tissues were analyzed for δ13C values. We consistently observed that particulate δ13C values were positively correlated with chlorophyll-a, carbonate chemistry, and to changes in the ratio of bicarbonate to dissolved carbon dioxide (HCO3-:CO2. While the relative proportion of HCO3- to CO2 increased over the 14 days, concentrations of each declined, reflecting the drawdown of carbon associated with enhanced production. Plankton δ13C values, like chlorophyll-a concentrations, increased over the course of each experiment, with the greatest increases in the moderate and high treatments. Trends in δ13C over time were also observed in the mussel tissues. Despite ecological variability and different plankton abundances the experiments consistently demonstrated how δ13C values in primary producers and consumers reflected nutrient availability, via its impact on carbonate chemistry. We

  5. Stable-carbon isotope ratios for sourcing the nerve-agent precursor methylphosphonic dichloride and its products.

    Science.gov (United States)

    Moran, James J; Fraga, Carlos G; Nims, Megan K

    2018-08-15

    The ability to connect a chemical threat agent to a specific batch of a synthetic precursor can provide a fingerprint to contribute to effective forensic investigations. Stable isotope analysis can leverage intrinsic, natural isotopic variability within the molecules of a threat agent to unlock embedded chemical fingerprints in the material. Methylphosphonic dichloride (DC) is a chemical precursor to the nerve agent sarin. DC is converted to methylphosphonic difluoride (DF) as part of the sarin synthesis process. We used a suite of commercially available DC stocks to both evaluate the potential for δ 13 C analysis to be used as a fingerprinting tool in sarin-related investigations and to develop sample preparation techniques (using chemical hydrolysis) that can simplify isotopic analysis of DC and its synthetic products. We demonstrate that natural isotopic variability in DC results in at least three distinct, isotope-resolved clusters within the thirteen stocks we analyzed. Isotopic variability in the carbon feedstock (i.e., methanol) used for DC synthesis is likely inherited by the DC samples we measured. We demonstrate that the hydrolysis of DC and DF to methylphosphonic acid (MPA) can be used as a preparative step for isotopic analysis because the reaction does not impart a significant isotopic fractionation. MPA is more chemically stable, less toxic, and easier to handle than DC or DF. Further, the hydrolysis method we demonstrated can be applied to a suite of other precursors or to sarin itself, thereby providing a potentially valuable forensic tool. Copyright © 2018. Published by Elsevier B.V.

  6. A universal carbonate ion effect on stable oxygen isotope ratios in unicellular planktonic calcifying organisms

    OpenAIRE

    Ziveri, P.; Thoms, S.; Probert, I.; Geisen, M.; Langer, H.

    2012-01-01

    The oxygen isotopic composition (δ18O) of calcium carbonate of planktonic calcifying organisms is a key tool for reconstructing both past seawater temperature and salinity. The calibration of paloeceanographic proxies relies in general on empirical relationships derived from field experiments on extant species. Laboratory experiments have more often than not revealed that variables other than the target parameter influence the proxy signal, which makes proxy c...

  7. Stable carbon isotope fractionation in the search for life on early Mars

    Science.gov (United States)

    Rothschild, L. J.; Desmarais, D.

    1989-01-01

    The utility of measurements of C-13/C-12 ratios in organic vs inorganic deposits for searching for signs of life on early Mars is considered. It is suggested that three assumptions are necessary. First, if there was life on Mars, it caused the fractionation of carbon isotopes in analogy with past biological activity on earth. Second, the fractionation would be detectable. Third, if a fractionation would be observed, there exist no abiotic explanations for the observed fractionation pattern.

  8. The application of stable carbon isotope ratios as water quality indicators in coastal areas of Karachi, Pakistan

    International Nuclear Information System (INIS)

    Qureshi, R.M.; Mashiatullah, A.; Javed, T.; Tasneem, M.A.; Sajjad, M.I.; Saleem, M.; Khan, S.H.; Rizvi, S.H.N.; Siddiqui, S.A.; Qari, R.

    1998-01-01

    Stable carbon isotope ratios (δ 13 C) of total dissolved inorganic carbon (TDIC), total inorganic and organic carbon in bottom sediments, as well as sea plants in polluted water sources, non-polluted Karachi Sea water and pollution recipients are used to elaborate pollution scenario of shallow marine environment off Karachi coast. These results are supplemented with stable isotope composition of nitrogen (δ 15 N) in seaweeds and mangroves, toxic/trace metal concentration in sea-bottom sediments, total Coliform bacterial population, electrical conductivity, temperature and turbidity. Isotopic data shows that the mangrove ecosystem and the tidal fluctuations play a key role in controlling contamination inventories in shallow sea water off Karachi coast, specifically the Manora Channel. The Karachi harbour zone is found to be the most heavily polluted marine site in Manora channel during high as well as low tide regimes. Significant concentrations of toxic metals such as Pb, Ni, Cr, Zn, V, U are observed in off-shore sediments of Karachi coast. The results show that sewage and industrial wastes are the main sources of heavy metal pollution in Karachi harbour, Manora Channel exit zone and the southeast coast. However, as compared to other coastal areas, the Karachi coast is moderately polluted. Studies suggest incorporation of quick remedial measures to combat pollution in shallow marine environments off Karachi Coast. (author)

  9. Stable Carbon Isotope Ratio (δ13C Measurement of Graphite Using EA-IRMS System

    Directory of Open Access Journals (Sweden)

    Andrius Garbaras

    2015-06-01

    Full Text Available δ13C values in non-irradiated natural graphite were measured. The measurements were carried out using an elemental analyzer combined with stable isotope ratio mass spectrometer (EA-IRMS. The samples were prepared with ground and non-ground graphite, the part of which was mixed with Mg (ClO42. The best combustion of graphite in the oxidation furnace of the elemental analyzer was achieved when the amount of pulverized graphite ranged from 200 to 490 µg and the mass ratio C:Mg(ClO42 was approximately 1:10. The method for the graphite burning avoiding the isotope fractionation is proposed.DOI: http://dx.doi.org/10.5755/j01.ms.21.2.6873

  10. Diet and mobility in Early Medieval Bavaria: a study of carbon and nitrogen stable isotopes.

    Science.gov (United States)

    Hakenbeck, Susanne; McManus, Ellen; Geisler, Hans; Grupe, Gisela; O'Connell, Tamsin

    2010-10-01

    This study investigates patterns of mobility in Early Medieval Bavaria through a combined study of diet and associated burial practice. Carbon and nitrogen isotope ratios were analyzed in human bone samples from the Late Roman cemetery of Klettham and from the Early Medieval cemeteries of Altenerding and Straubing-Bajuwarenstrasse. For dietary comparison, samples of faunal bone from one Late Roman and three Early Medieval settlement sites were also analyzed. The results indicate that the average diet was in keeping with a landlocked environment and fairly limited availability of freshwater or marine resources. The diet appears not to have changed significantly from the Late Roman to the Early Medieval period. However, in the population of Altenerding, there were significant differences in the diet of men and women, supporting a hypothesis of greater mobility among women. Furthermore, the isotopic evidence from dietary outliers is supported by "foreign" grave goods and practices, such as artificial skull modification. These results reveal the potential of carbon and nitrogen isotope analysis for questions regarding migration and mobility. © 2010 Wiley-Liss, Inc.

  11. Stable carbon isotope ratio profiling of illicit testosterone preparations--domestic and international seizures.

    Science.gov (United States)

    Brooker, Lance; Cawley, Adam; Drury, Jason; Edey, Claire; Hasick, Nicole; Goebel, Catrin

    2014-10-01

    Gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) is now established as a robust and mature analytical technique for the doping control of endogenous anabolic androgenic steroids in human sport. It relies on the assumption that the carbon isotope ratios of naturally produced steroids are significantly different to synthetically manufactured testosterone or testosterone prohormones used in commercial medical or dietary supplement products. Recent publications in this journal have highlighted the existence of black market testosterone preparations with carbon isotope ratios within the range reported for endogenous steroids (i.e. δ(13) C ≥ -25.8 ‰). In this study, we set out to profile domestic and international law enforcement seizures of illicit testosterone products to monitor the prevalence of 'enriched' substrates--which if administered to human subjects would be considered problematic for the use of current GC-C-IRMS methodologies for the doping control of testosterone in sport. The distribution of δ(13) C values for this illicit testosterone sample population (n = 283) ranged from -23.4 ‰ to -32.9 ‰ with mean and median of -28.6 ‰--comparable to previous work. However, only 13 out of 283 testosterone samples (4.6 %) were found to display δ(13) C values ≥ -25.8 ‰, confirming that in the vast majority of cases of illicit testosterone administration, current GC-C-IRMS doping control procedures would be capable of confirming misuse. Copyright © 2014 John Wiley & Sons, Ltd.

  12. Impact of contamination and pre-treatment on stable carbon and nitrogen isotopic composition of charred plant remains.

    Science.gov (United States)

    Vaiglova, Petra; Snoeck, Christophe; Nitsch, Erika; Bogaard, Amy; Lee-Thorp, Julia

    2014-12-15

    Stable isotope analysis of archaeological charred plants has become a useful tool for interpreting past agricultural practices and refining ancient dietary reconstruction. Charred material that lay buried in soil for millennia, however, is susceptible to various kinds of contamination, whose impact on the grain/seed isotopic composition is poorly understood. Pre-treatment protocols have been adapted in distinct forms from radiocarbon dating, but insufficient research has been carried out on evaluating their effectiveness and necessity for stable carbon and nitrogen isotope analysis. The effects of previously used pre-treatment protocols on the isotopic composition of archaeological and modern sets of samples were investigated. An archaeological sample was also artificially contaminated with carbonates, nitrates and humic acid and subjected to treatment aimed at removing the introduced contamination. The presence and removal of the contamination were investigated using Fourier transform infrared spectroscopy (FTIR) and δ(13)C and δ(15)N values. The results show a ca 1‰ decrease in the δ(15)N values of archaeological charred plant material caused by harsh acid treatments and ultra-sonication. This change is interpreted as being caused by mechanical distortion of the grains/seeds rather than by the removal of contamination. Furthermore, specific infrared peaks have been identified that can be used to detect the three types of contaminants studied. We argue that it is not necessary to try to remove humic acid contamination for stable isotope analysis. The advantages and disadvantages of crushing the grains/seeds before pre-treatment are discussed. We recommend the use of an acid-only procedure (0.5 M HCl for 30 min at 80 °C followed by three rinses in distilled water) for cleaning charred plant remains. This study fills an important gap in plant stable isotope research that will enable future researchers to evaluate potential sources of isotopic change and pre

  13. Stable carbon and nitrogen isotope signatures indicate recovery of marine biota from sewage pollution at Moa Point, New Zealand

    International Nuclear Information System (INIS)

    Rogers, Karyne M.

    2003-01-01

    Stable carbon and nitrogen isotopes have been used to assess sewage contamination of a sewage outfall, discharging milli-screened effluent into Moa Point Bay, New Zealand, and monitor the recovery of flora and fauna after the outfall's closure. An initial study characterising the extent of the discharge and the effects on seaweed (Ulva lactuca L.), blue mussels (Mytilus galloprovincialis) and limpets (Cellana denticulata) from the area, showed effects of the sewage discharge on flora and fauna were localised within in the bay. The immediate area surrounding the discharge area was found to contain limited biodiversity, with an abundance of Ulva lactuca, a bright green lettuce-like seaweed, typically found in areas with high nutrient input, limpets and small blue mussels. The nitrogen isotopic signature (δ 15 N) is shown to be a good tracer of sewage pollution in seaweed and associated grazers (i.e. limpets) as a result of the increased contribution of urea and ammonia to seawater nitrogen derived from the effluent. The carbon isotopic signature (δ 13 C) is suggested as a more appropriate sewage tracer for mussels, which filter feed the effluent's particulate organic matter from the water. Lower carbon:nitrogen ratios were found in Ulva lactuca sampled from around the outfall region compared to uncontaminated control sites. However carbon:nitrogen ratios do not vary significantly amongst shellfish species. After closure, monitoring continued for 9 months and showed that the carbon and nitrogen isotopic signatures of algae (Ulva lactuca L.) returned to similar control site levels within 3 months. Limpet and blue mussels (Cellana denticulata and Mytilus galloprovincialis) showed slower recovery times than the Ulva lactuca, with detectable levels of the sewage-derived carbon and nitrogen remaining in the animal's tissue for up to 9 months

  14. Stable carbon and nitrogen isotope signatures indicate recovery of marine biota from sewage pollution at Moa Point, New Zealand

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, Karyne M

    2003-07-01

    Stable carbon and nitrogen isotopes have been used to assess sewage contamination of a sewage outfall, discharging milli-screened effluent into Moa Point Bay, New Zealand, and monitor the recovery of flora and fauna after the outfall's closure. An initial study characterising the extent of the discharge and the effects on seaweed (Ulva lactuca L.), blue mussels (Mytilus galloprovincialis) and limpets (Cellana denticulata) from the area, showed effects of the sewage discharge on flora and fauna were localised within in the bay. The immediate area surrounding the discharge area was found to contain limited biodiversity, with an abundance of Ulva lactuca, a bright green lettuce-like seaweed, typically found in areas with high nutrient input, limpets and small blue mussels. The nitrogen isotopic signature ({delta}{sup 15}N) is shown to be a good tracer of sewage pollution in seaweed and associated grazers (i.e. limpets) as a result of the increased contribution of urea and ammonia to seawater nitrogen derived from the effluent. The carbon isotopic signature ({delta}{sup 13}C) is suggested as a more appropriate sewage tracer for mussels, which filter feed the effluent's particulate organic matter from the water. Lower carbon:nitrogen ratios were found in Ulva lactuca sampled from around the outfall region compared to uncontaminated control sites. However carbon:nitrogen ratios do not vary significantly amongst shellfish species. After closure, monitoring continued for 9 months and showed that the carbon and nitrogen isotopic signatures of algae (Ulva lactuca L.) returned to similar control site levels within 3 months. Limpet and blue mussels (Cellana denticulata and Mytilus galloprovincialis) showed slower recovery times than the Ulva lactuca, with detectable levels of the sewage-derived carbon and nitrogen remaining in the animal's tissue for up to 9 months.

  15. Effect of baking and fermentation on the stable carbon and nitrogen isotope ratios of grain-based food.

    Science.gov (United States)

    Bostic, Joshua N; Palafox, Sherilyn J; Rottmueller, Marina E; Jahren, A Hope

    2015-05-30

    Isotope ratio mass spectrometry (IRMS) is used extensively to reconstruct general attributes of prehistoric and modern diets in both humans and animals. In order to apply these methods to the accurate determination of specific intakes of foods/nutrients of interest, the isotopic signature of individually consumed foods must be constrained. For example, 86% of the calories consumed in the USA are derived from processed and prepared foods, but the relationship between the stable isotope composition of raw ingredients and the resulting products has not been characterized. To examine the effect of common cooking techniques on the stable isotope composition of grain-based food items, we prepared yeast buns and sugar cookies from standardized recipes and measured bulk δ(13) C and δ(15) N values of samples collected throughout a 75 min fermentation process (buns) and before and after baking at 190°C (buns and cookies). Simple isotope mixing models were used to determine if the isotopic signatures of 13 multi-ingredient foods could be estimated from the isotopic signatures of their constituent raw ingredients. No variations in δ(13) C or δ(15) N values were detected between pre- and post-baked yeast buns (pre: -24.78‰/2.61‰, post: -24.75‰/2.74‰), beet-sugar cookies (pre: -24.48‰/3.84‰, post: -24.47‰/3.57‰), and cane-sugar cookies (pre: -19.07‰/2.97‰, post: -19.02‰/3.21‰), or throughout a 75 min fermentation process in yeast buns. Using isotopic mass balance equations, the δ(13) C/δ(15) N values of multi-ingredient foods were estimated from the isotopic composition of constituent raw ingredients to within 0.14 ± 0.13‰/0.24 ± 0.17‰ for gravimetrically measured recipes and 0.40 ± 0.38‰/0.58 ± 0.53‰ for volumetrically measured recipes. Two common food preparation techniques, baking and fermentation, do not substantially affect the carbon or nitrogen isotopic signature of grain-based foods. Mass-balance equations can be used to

  16. Effects of Water Vapor on the Data Quality of the Stable Oxygen Isotopic Ratio of Atmospheric Carbon Dioxide

    Science.gov (United States)

    Evans, C. U.; White, J. W.; Vaughn, B.; Tans, P. P.; Pardo, L.

    2007-12-01

    The stable oxygen isotopic ratio of carbon dioxide can potentially track fundamental indicators of environmental change such as the balance between photosynthesis and respiration on regional to global scales. The Stable Isotope Laboratory (SIL) at the Institute of Arctic and Alpine Research (INSTAAR), University of Colorado at Boulder, has measured the stable isotopes of atmospheric carbon dioxide from more than 60 NOAA/Earth System Research Laboratory (ESRL) air flask-sampling sites since the early 1990s. If air is sampled without drying, oxygen can exchange between carbon dioxide and water in the flasks, entirely masking the desired signal. An attempt to investigate how water vapor is affecting the δ18O signal is accomplished by comparing the SIL measurements with specific humidity, calculated from the National Climatic Data Center (NCDC) global integrated surface hourly temperature and dew point database, at the time of sampling. Analysis of sites where samples have been collected initially without drying, and subsequently with a drying kit, in conjunction with the humidity data, has led to several conclusions. Samples that initially appear isotopically unaltered, in that their δ18O values are within the expected range, are being subtly influenced by the water vapor in the air. At Bermuda and other tropical to semi-tropical sites, the 'wet' sampling values have a seasonal cycle that is strongly anti-correlated to the specific humidity, while the 'dry' values have a seasonal cycle that is shifted earlier than the specific humidity cycle by 1-2 months. The latter phasing is expected given the seasonal phasing between climate over the ocean and land, while the former is consistent with a small, but measurable isotope exchange in the flasks. In addition, we note that there is a strong (r > 0.96) correlation between the average specific humidity and the percent of rejected samples for 'wet' sampling. This presents an opportunity for determining a threshold of

  17. Investigation of the microbial metabolism of carbon dioxide and hydrogen in the kangaroo foregut by stable isotope probing.

    Science.gov (United States)

    Godwin, Scott; Kang, Alicia; Gulino, Lisa-Maree; Manefield, Mike; Gutierrez-Zamora, Maria-Luisa; Kienzle, Marco; Ouwerkerk, Diane; Dawson, Kerri; Klieve, Athol V

    2014-09-01

    Kangaroos ferment forage material in an enlarged forestomach analogous to the rumen, but in contrast to ruminants, they produce little or no methane. The objective of this study was to identify the dominant organisms and pathways involved in hydrogenotrophy in the kangaroo forestomach, with the broader aim of understanding how these processes are able to predominate over methanogenesis. Stable isotope analysis of fermentation end products and RNA stable isotope probing (RNA-SIP) were used to investigate the organisms and biochemical pathways involved in the metabolism of hydrogen and carbon dioxide in the kangaroo forestomach. Our results clearly demonstrate that the activity of bacterial reductive acetogens is a key factor in the reduced methane output of kangaroos. In in vitro fermentations, the microbial community of the kangaroo foregut produced very little methane, but produced a significantly greater proportion of acetate derived from carbon dioxide than the microbial community of the bovine rumen. A bacterial operational taxonomic unit closely related to the known reductive acetogen Blautia coccoides was found to be associated with carbon dioxide and hydrogen metabolism in the kangaroo foregut. Other bacterial taxa including members of the genera Prevotella, Oscillibacter and Streptococcus that have not previously been reported as containing hydrogenotrophic organisms were also significantly associated with metabolism of hydrogen and carbon dioxide in the kangaroo forestomach.

  18. Freezing and fractionation: effects of preservation on carbon and nitrogen stable isotope ratios of some limnetic organisms.

    Science.gov (United States)

    Wolf, J Marshall; Johnson, Brett; Silver, Douglas; Pate, William; Christianson, Kyle

    2016-03-15

    Stable isotopes of carbon and nitrogen have become important natural tracers for studying food-web structure and function. Considerable research has demonstrated that chemical preservatives and fixatives shift the isotopic ratios of aquatic organisms. Much less is known about the effects of freezing as a preservation method although this technique is commonly used. We conducted a controlled experiment to test the effects of freezing (-10 °C) and flash freezing (–79 °C) on the carbon and nitrogen isotope ratios of zooplankton (Cladocera), Mysis diluviana and Rainbow Trout (Oncorhynchus mykiss). Subsamples (~0.5 mg) of dried material were analyzed for percentage carbon, percentage nitrogen, and the relative abundance of stable carbon and nitrogen isotopes (δ13C and δ15N values) using a Carlo Erba NC2500 elemental analyzer interfaced to a ThermoFinnigan MAT Delta Plus isotope ratio mass spectrometer. The effects of freezing were taxon-dependent. Freezing had no effect on the isotopic or elemental values of Rainbow Trout muscle. Effects on the δ13C and δ15N values of zooplankton and Mysis were statistically significant but small relative to typical values of trophic fractionation. The treatment-control offsets had larger absolute values for Mysis (δ13C: ≤0.76 ± 0.41‰, δ15N: ≤0.37 ± 0.16‰) than for zooplankton (δ13C: ≤0.12 ± 0.06‰, δ15N: ≤0.30 ± 0.27‰). The effects of freezing were more variable for the δ13C values of Mysis, and more variable for the δ15N values of zooplankton. Generally, both freezing methods reduced the carbon content of zooplankton and Mysis, but freezing had a negative effect on the %N of zooplankton and a positive effect on the %N of Mysis. The species-dependencies and variability of freezing effects on aquatic organisms suggest that more research is needed to understand the mechanisms responsible for freezing-related fractionation before standardized protocols for freezing as a preservation method can be adopted.

  19. A new CF-IRMS system for quantifying stable isotopes of carbon monoxide from ice cores and small air samples

    Directory of Open Access Journals (Sweden)

    Z. Wang

    2010-10-01

    Full Text Available We present a new analysis technique for stable isotope ratios (δ13C and δ18O of atmospheric carbon monoxide (CO from ice core samples. The technique is an online cryogenic vacuum extraction followed by continuous-flow isotope ratio mass spectrometry (CF-IRMS; it can also be used with small air samples. The CO extraction system includes two multi-loop cryogenic cleanup traps, a chemical oxidant for oxidation to CO2, a cryogenic collection trap, a cryofocusing unit, gas chromatography purification, and subsequent injection into a Finnigan Delta Plus IRMS. Analytical precision of 0.2‰ (±1δ for δ13C and 0.6‰ (±1δ for δ18O can be obtained for 100 mL (STP air samples with CO mixing ratios ranging from 60 ppbv to 140 ppbv (~268–625 pmol CO. Six South Pole ice core samples from depths ranging from 133 m to 177 m were processed for CO isotope analysis after wet extraction. To our knowledge, this is the first measurement of stable isotopes of CO in ice core air.

  20. Bone collagen stable carbon and nitrogen isotope variability in modern South Australian mammals: A baseline for palaeoecological inferences

    International Nuclear Information System (INIS)

    Pate, F.D.; Anson, T.J.; Noble, A.H.; Schoeninger, M.J.

    1997-01-01

    Cortical bone samples were collected from a range of modern mammals at four field sites along a 1225 km north-south transect from temperate coastal to arid interior South Australia in order to address variability in stable carbon and nitrogen isotope composition. Collection sites were located along the eastern border of the state and included Mount Gambier, Karte, Plumbago and Innamincka. Mean annual rainfall along the transect ranges from 700-800 mm at Mount Gambier to 150-200 mm at Innamincka. Bone collagen carbon and nitrogen isotope values become more positive toward the arid north in relation to increasing quantities of C-4 plants and decreasing amounts of rainfall. respectively. In addition, carnivores and herbivores can be differentiated by stable nitrogen isotope values. On average, carnivore bone collagen is approximately 6 per mil more positive than that of rabbits at Mount Gambier but only 2.6 - 3.4 per mil more positive at the three arid collection sites. In general, the large eutherian herbivores have mean bone collagen δ15N values that are 1.4 - 2.3 per mil more positive than those of the marsupial herbivores. Eutherian and marsupial bone collagen δ15N differences only disappear at the most arid collection site, Innamincka

  1. Trophic relationships and habitat preferences of delphinids from the southeastern Brazilian coast determined by carbon and nitrogen stable isotope composition.

    Directory of Open Access Journals (Sweden)

    Tatiana Lemos Bisi

    Full Text Available To investigate the foraging habitats of delphinids in southeastern Brazil, we analyzed stable carbon (δ(13C and nitrogen (δ(15N isotopes in muscle samples of the following 10 delphinid species: Sotalia guianensis, Stenella frontalis, Tursiops truncatus, Steno bredanensis, Pseudorca crassidens, Delphinus sp., Lagenodelphis hosei, Stenella attenuata, Stenella longirostris and Grampus griseus. We also compared the δ(13C and δ(15N values among four populations of S. guianensis. Variation in carbon isotope results from coast to ocean indicated that there was a significant decrease in δ(13C values from estuarine dolphins to oceanic species. S. guianensis from Guanabara Bay had the highest mean δ(13C value, while oceanic species showed significantly lower δ(13C values. The highest δ(15N values were observed for P. crassidens and T. truncatus, suggesting that these species occupy the highest trophic position among the delphinids studied here. The oceanic species S. attenuata, G. griseus and L. hosei had the lowest δ(15N values. Stable isotope analysis showed that the three populations of S. guianensis in coastal bays had different δ(13C values, but similar δ(15N results. Guiana dolphins from Sepetiba and Ilha Grande bays had different foraging habitat, with specimens from Ilha Grande showing more negative δ(13C values. This study provides further information on the feeding ecology of delphinids occurring in southeastern Brazil, with evidence of distinctive foraging habitats and the occupation of different ecological niches by these species in the study area.

  2. Bone collagen stable carbon and nitrogen isotope variability in modern South Australian mammals: A baseline for palaeoecological inferences.

    Energy Technology Data Exchange (ETDEWEB)

    Pate, F.D.; Anson, T.J.; Noble, A.H. [Flinders Univ. of South Australia, Bedford Park, SA (Australia). Department of Archaeology; Schoeninger, M.J. [Wisconsin Univ., Madison, WI (United States). Department of Anthropology

    1997-12-31

    Cortical bone samples were collected from a range of modern mammals at four field sites along a 1225 km north-south transect from temperate coastal to arid interior South Australia in order to address variability in stable carbon and nitrogen isotope composition. Collection sites were located along the eastern border of the state and included Mount Gambier, Karte, Plumbago and Innamincka. Mean annual rainfall along the transect ranges from 700-800 mm at Mount Gambier to 150-200 mm at Innamincka. Bone collagen carbon and nitrogen isotope values become more positive toward the arid north in relation to increasing quantities of C-4 plants and decreasing amounts of rainfall. respectively. In addition, carnivores and herbivores can be differentiated by stable nitrogen isotope values. On average, carnivore bone collagen is approximately 6 per mil more positive than that of rabbits at Mount Gambier but only 2.6 - 3.4 per mil more positive at the three arid collection sites. In general, the large eutherian herbivores have mean bone collagen {delta}15N values that are 1.4 - 2.3 per mil more positive than those of the marsupial herbivores. Eutherian and marsupial bone collagen {delta}15N differences only disappear at the most arid collection site, Innamincka.

  3. Postmortem study of stable carbon isotope ratios in human cerebellar DNA: preliminary results

    International Nuclear Information System (INIS)

    Slatkin, D.N.; Irsa, A.P.; Friedman, L.

    1978-01-01

    It is observed that 13 C/ 12 C ratios in tissue specimens removed postmortem in the United States and Canada are significantly different from corresponding ratios in European specimens. On the basis of this information, measurements of carbon isotope ratios in DNA isolated from cerebella of native-born and European-born North Americans are in progress with the goal of estimating the average lifetime rate of DNA turnover in human neurons. Preliminary results from twenty postmortem examinations are consistent with the hypothesis that a significant proportion of human cerebellar DNA is renewed during the lifetime of an individual

  4. Stable carbon isotope ratios of lipid biomarkers and their applications in the marine environment

    International Nuclear Information System (INIS)

    Tolosa, I.; Mora, S. de

    2001-01-01

    Studies on the distribution of lipid biomarkers in the environment help elucidate biogeochemical processes, but recent findings have significantly reduced the specificity of some biomarkers. The analytical development of Gas Chromatography-Combustion-IRMS (GC-C-IRMS) allows the determination of the δ 13 C of specific biomarkers, thereby improving the veracity of source apportionment. In this report, we present a brief description of the analytical approach for sample preparation and carbon isotope measurements of individual biomarkers. Selected examples of the applications in the use of GC-C-IRMS for biomarker source elucidation in the marine environment and potential applications to paleoclimatological studies are reviewed. (author)

  5. Stable carbon isotope fractionation of chlorinated ethenes by a microbial consortium containing multiple dechlorinating genes.

    Science.gov (United States)

    Liu, Na; Ding, Longzhen; Li, Haijun; Zhang, Pengpeng; Zheng, Jixing; Weng, Chih-Huang

    2018-08-01

    The study aimed to determine the possible contribution of specific growth conditions and community structures to variable carbon enrichment factors (Ɛ- carbon ) values for the degradation of chlorinated ethenes (CEs) by a bacterial consortium with multiple dechlorinating genes. Ɛ- carbon values for trichloroethylene, cis-1,2-dichloroethylene, and vinyl chloride were -7.24% ± 0.59%, -14.6% ± 1.71%, and -21.1% ± 1.14%, respectively, during their degradation by a microbial consortium containing multiple dechlorinating genes including tceA and vcrA. The Ɛ- carbon values of all CEs were not greatly affected by changes in growth conditions and community structures, which directly or indirectly affected reductive dechlorination of CEs by this consortium. Stability analysis provided evidence that the presence of multiple dechlorinating genes within a microbial consortium had little effect on carbon isotope fractionation, as long as the genes have definite, non-overlapping functions. Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates.

    Science.gov (United States)

    Moerdijk-Poortvliet, Tanja C W; Schierbeek, Henk; Houtekamer, Marco; van Engeland, Tom; Derrien, Delphine; Stal, Lucas J; Boschker, Henricus T S

    2015-07-15

    We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of δ(13)C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence, although LC/IRMS is expected to be more accurate and precise, no direct comparison has been reported. GC/IRMS with the aldonitrile penta-acetate (ANPA) derivatisation method was compared with LC/IRMS without derivatisation. A large number of glucose standards and a variety of natural samples were analysed for five neutral carbohydrates at natural abundance as well as at (13)C-enriched levels. Gas chromatography/chemical ionisation mass spectrometry (GC/CIMS) was applied to check for incomplete derivatisation of the carbohydrate, which would impair the accuracy of the GC/IRMS method. The LC/IRMS technique provided excellent precision (±0.08‰ and ±3.1‰ at natural abundance and enrichment levels, respectively) for the glucose standards and this technique proved to be superior to GC/IRMS (±0.62‰ and ±19.8‰ at natural abundance and enrichment levels, respectively). For GC/IRMS measurements the derivatisation correction and the conversion of carbohydrates into CO2 had a considerable effect on the measured δ(13)C values. However, we did not find any significant differences in the accuracy of the two techniques over the full range of natural δ(13)C abundances and (13)C-labelled glucose. The difference in the performance of GC/IRMS and LC/IRMS diminished when the δ(13)C values were measured in natural samples, because the chromatographic performance and background correction became critical factors, particularly for LC/IRMS. The derivatisation of carbohydrates for the GC/IRMS method was complete. Although both LC/IRMS and GC/IRMS are reliable techniques for compound-specific stable carbon isotope analysis of carbohydrates (provided that derivatisation is complete and the

  7. Preservation Methods Alter Carbon and Nitrogen Stable Isotope Values in Crickets (Orthoptera: Grylloidea).

    Science.gov (United States)

    Jesus, Fabiene Maria; Pereira, Marcelo Ribeiro; Rosa, Cassiano Sousa; Moreira, Marcelo Zacharias; Sperber, Carlos Frankl

    2015-01-01

    Stable isotope analysis (SIA) is an important tool for investigation of animal dietary habits for determination of feeding niche. Ideally, fresh samples should be used for isotopic analysis, but logistics frequently demands preservation of organisms for analysis at a later time. The goal of this study was to establish the best methodology for preserving forest litter-dwelling crickets for later SIA analysis without altering results. We collected two cricket species, Phoremia sp. and Mellopsis doucasae, from which we prepared 70 samples per species, divided among seven treatments: (i) freshly processed (control); preserved in fuel ethanol for (ii) 15 and (iii) 60 days; preserved in commercial ethanol for (iv) 15 and (v) 60 days; fresh material frozen for (vi) 15 and (vii) 60 days. After oven drying, samples were analyzed for δ15N, δ13C values, N(%), C(%) and C/N atomic values using continuous flow isotope ratio mass spectrometry. All preservation methods tested, significantly impacted δ13C and δ15N and C/N atomic values. Chemical preservatives caused δ13C enrichment as great as 1.5‰, and δ15N enrichment as great as 0.9‰; the one exception was M. doucasae stored in ethanol for 15 days, which had δ15N depletion up to 1.8‰. Freezing depleted δ13C and δ15N by up to 0.7 and 2.2‰, respectively. C/N atomic values decreased when stored in ethanol, and increased when frozen for 60 days for both cricket species. Our results indicate that all preservation methods tested in this study altered at least one of the tested isotope values when compared to fresh material (controls). We conclude that only freshly processed material provides adequate SIA results for litter-dwelling crickets.

  8. Preservation Methods Alter Carbon and Nitrogen Stable Isotope Values in Crickets (Orthoptera: Grylloidea.

    Directory of Open Access Journals (Sweden)

    Fabiene Maria Jesus

    Full Text Available Stable isotope analysis (SIA is an important tool for investigation of animal dietary habits for determination of feeding niche. Ideally, fresh samples should be used for isotopic analysis, but logistics frequently demands preservation of organisms for analysis at a later time. The goal of this study was to establish the best methodology for preserving forest litter-dwelling crickets for later SIA analysis without altering results. We collected two cricket species, Phoremia sp. and Mellopsis doucasae, from which we prepared 70 samples per species, divided among seven treatments: (i freshly processed (control; preserved in fuel ethanol for (ii 15 and (iii 60 days; preserved in commercial ethanol for (iv 15 and (v 60 days; fresh material frozen for (vi 15 and (vii 60 days. After oven drying, samples were analyzed for δ15N, δ13C values, N(%, C(% and C/N atomic values using continuous flow isotope ratio mass spectrometry. All preservation methods tested, significantly impacted δ13C and δ15N and C/N atomic values. Chemical preservatives caused δ13C enrichment as great as 1.5‰, and δ15N enrichment as great as 0.9‰; the one exception was M. doucasae stored in ethanol for 15 days, which had δ15N depletion up to 1.8‰. Freezing depleted δ13C and δ15N by up to 0.7 and 2.2‰, respectively. C/N atomic values decreased when stored in ethanol, and increased when frozen for 60 days for both cricket species. Our results indicate that all preservation methods tested in this study altered at least one of the tested isotope values when compared to fresh material (controls. We conclude that only freshly processed material provides adequate SIA results for litter-dwelling crickets.

  9. Stable isotope analysis in primatology: a critical review.

    Science.gov (United States)

    Sandberg, Paul A; Loudon, James E; Sponheimer, Matt

    2012-11-01

    Stable isotope analysis has become an important tool in ecology over the last 25 years. A wealth of ecological information is stored in animal tissues in the relative abundances of the stable isotopes of several elements, particularly carbon and nitrogen, because these isotopes navigate through ecological processes in predictable ways. Stable carbon and nitrogen isotopes have been measured in most primate taxonomic groups and have yielded information about dietary content, dietary variability, and habitat use. Stable isotopes have recently proven useful for addressing more fine-grained questions about niche dynamics and anthropogenic effects on feeding ecology. Here, we discuss stable carbon and nitrogen isotope systematics and critically review the published stable carbon and nitrogen isotope data for modern primates with a focus on the problems and prospects for future stable isotope applications in primatology. © 2012 Wiley Periodicals, Inc.

  10. Carbonate Mineral Formation on Mars: Clues from Stable Isotope Variation Seen in Cryogenic Laboratory Studies of Carbonate Salts

    Science.gov (United States)

    Socki, Richard; Niles, Paul B.; Sun, Tao; Fu, Qi; Romanek, Christopher S.; Gibson, Everett K.

    2013-01-01

    The geologic history of water on the planet Mars is intimately connected to the formation of carbonate minerals through atmospheric CO2 and its control of the climate history of Mars. Carbonate mineral formation under modern martian atmospheric conditions could be a critical factor in controlling the martian climate in a means similar to the rock weathering cycle on Earth. The combination of evidence for liquid water on the martian surface and cold surface conditions suggest fluid freezing could be very common on the surface of Mars. Cryogenic calcite forms readily when a rise in pH occurs as a result of carbon dioxide degassing quickly from freezing Ca-bicarbonate-rich water solutions. This is a process that has been observed in some terrestrial settings such as arctic permafrost cave deposits, lakebeds of the Dry Valleys of Antarctica, and in aufeis (river icings) from rivers of N.E. Alaska. We report here the results of a series of laboratory experiments that were conducted to simulate potential cryogenic carbonate formation on the planet Mars. These results indicate that carbonates grown under martian conditions (controlled atmospheric pressure and temperature) show enrichments from starting bicarbonate fluids in both carbon and oxygen isotopes beyond equilibrium values with average delta13C(DIC-CARB) values of 20.5%0 which exceed the expected equilibrium fractionation factor of [10(sup 3) ln alpha = 13%0] at 0 degC. Oxygen isotopes showed a smaller enrichment with delta18O(H2O-CARB) values of 35.5%0, slightly exceeding the equilibrium fractionation factor of [10(sup 3) ln alpha = 34%0 ] at 0degC. Large kinetic carbon isotope effects during carbonate precipitation could substantially affect the carbon isotope evolution of CO2 on Mars allowing for more efficient removal of 13C from the Noachian atmosphere enriched by atmospheric loss. This mechanism would be consistent with the observations of large carbon isotope variations in martian materials despite the

  11. Applications of stable isotopes

    International Nuclear Information System (INIS)

    Gregg, C.T.

    1977-01-01

    Clinical applications include the galactose breath test which consists of oral administration of 13 C-labeled galactose and measurement of the 13 C content of respired CO 2 as a function of time in patients with cirrhotic livers for diagnosis of liver dysfunction. Another application was the breath test to study glucose metabolism in children. Respired 13 CO 2 from ingested glucose- 13 C was measured for normal and diabetic children. Studies on mice in which 60 percent of the body carbon was replaced with 13 C failed to show significant effects of the isotope. Studies on biochemical applications include nuclear magnetic resonance studies of 13 C-labeled amino acids from Chlorella pyrenoidosa; studies on 15 N nmr spectra of arginine-guanidino- 13 C-2,3-- 15 N 2 as a function of pH; and isolation of fatty acids from algae

  12. Stable-isotope paleoclimatology

    International Nuclear Information System (INIS)

    Deuser, W.G.

    1978-01-01

    Seasonal variations of temperature and salinity in the surface waters of large parts of the oceans are well established. Available data on seasonal distributions of planktonic foraminifera show that the abundances of different species groups peak at different times of the year with an apparent succession of abundance peaks through most of the year. This evidence suggests that a measure of seasonal contrast is recorded in the isotope ratios of oxygen, and perhaps carbon, in the tests of different foraminiferal species. The evaluation of this potential paleoclimatologic tool awaits planned experiments with recent foraminifera in well-known settings, but a variety of available data is consistent with the idea that interspecies differences in 18 O content contain a seasonal component.(auth.)

  13. Tracing carbon flow in an arctic marine food web using fatty acid-stable isotope analysis.

    Science.gov (United States)

    Budge, S M; Wooller, M J; Springer, A M; Iverson, S J; McRoy, C P; Divoky, G J

    2008-08-01

    Global warming and the loss of sea ice threaten to alter patterns of productivity in arctic marine ecosystems because of a likely decline in primary productivity by sea ice algae. Estimates of the contribution of ice algae to total primary production range widely, from just 3 to >50%, and the importance of ice algae to higher trophic levels remains unknown. To help answer this question, we investigated a novel approach to food web studies by combining the two established methods of stable isotope analysis and fatty acid (FA) analysis--we determined the C isotopic composition of individual diatom FA and traced these biomarkers in consumers. Samples were collected near Barrow, Alaska and included ice algae, pelagic phytoplankton, zooplankton, fish, seabirds, pinnipeds and cetaceans. Ice algae and pelagic phytoplankton had distinctive overall FA signatures and clear differences in delta(13)C for two specific diatom FA biomarkers: 16:4n-1 (-24.0+/-2.4 and -30.7+/-0.8 per thousand, respectively) and 20:5n-3 (-18.3+/-2.0 and -26.9+/-0.7 per thousand, respectively). Nearly all delta(13)C values of these two FA in consumers fell between the two stable isotopic end members. A mass balance equation indicated that FA material derived from ice algae, compared to pelagic diatoms, averaged 71% (44-107%) in consumers based on delta(13)C values of 16:4n-1, but only 24% (0-61%) based on 20:5n-3. Our estimates derived from 16:4n-1, which is produced only by diatoms, probably best represented the contribution of ice algae relative to pelagic diatoms. However, many types of algae produce 20:5n-3, so the lower value derived from it likely represented a more realistic estimate of the proportion of ice algae material relative to all other types of phytoplankton. These preliminary results demonstrate the potential value of compound-specific isotope analysis of marine lipids to trace C flow through marine food webs and provide a foundation for future work.

  14. Some carbonates from Lagoa Real uranium province, State of Bahia: studies on fluid inclusion and stable isotope

    International Nuclear Information System (INIS)

    Fuzikawa, K.

    1982-01-01

    The geochemical conditions of the uraniferous carbonates of Lagoa Real province were studied using the fluid inclusions method and the isotopic determinations of the carbon and oxygen of these carbonates. (A.B.) [pt

  15. The stable carbon isotope biogeochemistry of acetate and other dissolved carbon species in deep subseafloor sediments at the northern Cascadia Margin

    Science.gov (United States)

    Heuer, Verena B.; Pohlman, John W.; Torres, Marta E.; Elvert, Marcus; Hinrichs, Kai-Uwe

    2009-01-01

    Ocean drilling has revealed the existence of vast microbial populations in the deep subseafloor, but to date little is known about their metabolic activities. To better understand the biogeochemical processes in the deep biosphere, we investigate the stable carbon isotope chemistry of acetate and other carbon-bearing metabolites in sediment pore-waters. Acetate is a key metabolite in the cycling of carbon in anoxic sediments. Its stable carbon isotopic composition provides information on the metabolic processes dominating acetate turnover in situ. This study reports our findings for a methane-rich site at the northern Cascadia Margin (NE Pacific) where Expedition 311 of the Integrated Ocean Drilling Program (IODP) sampled the upper 190 m of sediment. At Site U1329, δ13C values of acetate span a wide range from −46.0‰ to −11.0‰ vs. VPDB and change systematically with sediment depth. In contrast, δ13C values of both the bulk dissolved organic carbon (DOC) (−21.6 ± 1.3‰ vs. VPDB) and the low-molecular-weight compound lactate (−20.9 ± 1.8‰ vs. VPDB) show little variability. These species are interpreted to represent the carbon isotopic composition of fermentation products. Relative to DOC, acetate is up to 23.1‰ depleted and up to 9.1‰ enriched in 13C. Broadly, 13C-depletions of acetate relative to DOC indicate flux of carbon from acetogenesis into the acetate pool while 13C-enrichments of pore-water acetate relative to DOC suggest consumption of acetate by acetoclastic methanogenesis. Isotopic relationships between acetate and lactate or DOC provide new information on the carbon flow and the presence and activity of specific functional microbial communities in distinct biogeochemical horizons of the sediment. In particular, they suggest that acetogenic CO2-reduction can coexist with methanogenic CO2-reduction, a notion contrary to the hypothesis that hydrogen levels are controlled by the thermodynamically most favorable electron

  16. Concentration and stable carbon isotopic composition of CO2 in cave air of Postojnska jama, Slovenia

    Directory of Open Access Journals (Sweden)

    Magda Mandic

    2013-09-01

    Full Text Available Partial pressure of CO2 (pCO2 and its isotopic composition (δ13CairCO2 were measured in Postojnska jama, Slovenia, at 10 locations inside the cave and outside the cave during a one-year period. At all interior locations the pCO2 was higher and δ13CairCO2 lower than in the outside atmosphere. Strong seasonal fluctuations in both parameters were observed at locations deeper in the cave, which are isolated from the cave air circulation. By using a binary mixing model of two sources of CO2, one of them being the atmospheric CO2, we show that the excess of CO2 in the cave air has a δ13C value of -23.3 ± 0.7 ‰, in reasonable agreement with the previously measured soil-CO2 δ13C values. The stable isotope data suggest that soil CO2 is brought to the cave by drip water.

  17. Stable isotope tracing of trout hatchery carbon to sediments and foodwebs of limestone spring creeks

    International Nuclear Information System (INIS)

    Hurd, Todd M.; Jesic, Slaven; Jerin, Jessica L.; Fuller, Nathan W.; Miller, David

    2008-01-01

    Limestone springs support productive ecosystems and fisheries, yet aquaculture may modify or impair these ecosystems. We determined trout hatchery organic contribution to spring creek sediments and foodwebs with natural abundance stable isotope methods. Hatchery feed, waste, and trout were significantly enriched in δ 13 C relative to autotrophs and wild fish. Spring creek sediments were enriched in δ 13 C toward the hatchery endmember relative to reference streams without hatcheries and relative to a larger larger-order, spring-influenced stream. Contribution of hatchery C to spring creek sediments was greatest during March and associated with greatest sediment %C. Contribution of hatchery C to pollution-tolerant isopod diet was 39-51% in a stream receiving limestone spring water via hatchery effluent. Isopods of one spring creek also relied on hatchery-derived C within one month of hatchery closure. Four years later, less pollution pollution-tolerant amphipods dominated and consumed non-vascular over vascular autotrophs (86%). Isopods of a second spring creek with an active hatchery did not appear to be using hatchery matter directly, but were enriched in δ 34 S relative to a spring creek tributary with no hatchery influence. Isopods in both of these streams were relatively enriched in δ 15 N, indicating general nutrient enrichment from surrounding agricultural land use. The contribution of hatchery vs. wild fish in diet of herons and egrets was traced with δ 13 C of guano. These birds were strongly dependent on stocked trout in a spring creek with a recently closed state trout hatchery, and also near another large, state-run hatchery. Heron dependence on hatchery fish in the spring creek decreased with time since hatchery closure. Use of stable isotope natural abundance techniques in karst spring creeks can reveal stream impairment due to aquaculture, specific C sources to bio-indicating consumers, losses of farmed fish to predation, and potential exposure

  18. Development of Stable Isotope Technology

    International Nuclear Information System (INIS)

    Jeong, Do Young; Kim, Cheol Jung; Han, Jae Min

    2009-03-01

    KAERI has obtained an advanced technology with singular originality for laser stable isotope separation. Objectives for this project are to get production technology of Tl-203 stable isotope used for medical application and are to establish the foundation of the pilot system, while we are taking aim at 'Laser Isotope Separation Technology to make resistance to the nuclear proliferation'. And we will contribute to ensuring a nuclear transparency in the world society by taking part in a practical group of NSG and being collaboration with various international groups related to stable isotope separation technology

  19. Stable isotope research pool inventory

    International Nuclear Information System (INIS)

    1980-12-01

    This report contains a listing of electromagnetically separated stable isotopes which are available for distribution within the United States for non-destructive research use from the Oak Ridge National Laboratory on a loan basis. This inventory includes all samples of stable isotopes in the Materials Research Collection and does not designate whether a sample is out on loan or in reprocessing

  20. Autotrophic and heterotrophic acquisition of carbon and nitrogen by a mixotrophic chrysophyte established through stable isotope analysis

    Science.gov (United States)

    Terrado, Ramon; Pasulka, Alexis L; Lie, Alle A-Y; Orphan, Victoria J; Heidelberg, Karla B; Caron, David A

    2017-01-01

    Collectively, phagotrophic algae (mixotrophs) form a functional continuum of nutritional modes between autotrophy and heterotrophy, but the specific physiological benefits of mixotrophic nutrition differ among taxa. Ochromonas spp. are ubiquitous chrysophytes that exhibit high nutritional flexibility, although most species generally fall towards the heterotrophic end of the mixotrophy spectrum. We assessed the sources of carbon and nitrogen in Ochromonas sp. strain BG-1 growing mixotrophically via short-term stable isotope probing. An axenic culture was grown in the presence of either heat-killed bacteria enriched with 15N and 13C, or unlabeled heat-killed bacteria and labeled inorganic substrates (13C-bicarbonate and 15N-ammonium). The alga exhibited high growth rates (up to 2 divisions per day) only until heat-killed bacteria were depleted. NanoSIMS and bulk IRMS isotope analyses revealed that Ochromonas obtained 84–99% of its carbon and 88–95% of its nitrogen from consumed bacteria. The chrysophyte assimilated inorganic 13C-carbon and 15N-nitrogen when bacterial abundances were very low, but autotrophic (photosynthetic) activity was insufficient to support net population growth of the alga. Our use of nanoSIMS represents its first application towards the study of a mixotrophic alga, enabling a better understanding and quantitative assessment of carbon and nutrient acquisition by this species. PMID:28524870

  1. Autotrophic and heterotrophic acquisition of carbon and nitrogen by a mixotrophic chrysophyte established through stable isotope analysis.

    Science.gov (United States)

    Terrado, Ramon; Pasulka, Alexis L; Lie, Alle A-Y; Orphan, Victoria J; Heidelberg, Karla B; Caron, David A

    2017-09-01

    Collectively, phagotrophic algae (mixotrophs) form a functional continuum of nutritional modes between autotrophy and heterotrophy, but the specific physiological benefits of mixotrophic nutrition differ among taxa. Ochromonas spp. are ubiquitous chrysophytes that exhibit high nutritional flexibility, although most species generally fall towards the heterotrophic end of the mixotrophy spectrum. We assessed the sources of carbon and nitrogen in Ochromonas sp. strain BG-1 growing mixotrophically via short-term stable isotope probing. An axenic culture was grown in the presence of either heat-killed bacteria enriched with 15 N and 13 C, or unlabeled heat-killed bacteria and labeled inorganic substrates ( 13 C-bicarbonate and 15 N-ammonium). The alga exhibited high growth rates (up to 2 divisions per day) only until heat-killed bacteria were depleted. NanoSIMS and bulk IRMS isotope analyses revealed that Ochromonas obtained 84-99% of its carbon and 88-95% of its nitrogen from consumed bacteria. The chrysophyte assimilated inorganic 13 C-carbon and 15 N-nitrogen when bacterial abundances were very low, but autotrophic (photosynthetic) activity was insufficient to support net population growth of the alga. Our use of nanoSIMS represents its first application towards the study of a mixotrophic alga, enabling a better understanding and quantitative assessment of carbon and nutrient acquisition by this species.

  2. Stable isotope research pool inventory

    International Nuclear Information System (INIS)

    1984-03-01

    This report contains a listing of electromagnetically separated stable isotopes which are available at the Oak Ridge National Laboratory for distribution for nondestructive research use on a loan basis. This inventory includes all samples of stable isotopes in the Research Materials Collection and does not designate whether a sample is out on loan or is in reprocessing. For some of the high abundance naturally occurring isotopes, larger amounts can be made available; for example, Ca-40 and Fe-56

  3. French days on stable isotopes

    International Nuclear Information System (INIS)

    2000-01-01

    These first French days on stable isotopes took place in parallel with the 1. French days of environmental chemistry. Both conferences had common plenary sessions. The conference covers all aspects of the use of stable isotopes in the following domains: medicine, biology, environment, tracer techniques, agronomy, food industry, geology, petroleum geochemistry, cosmo-geochemistry, archaeology, bio-geochemistry, hydrology, climatology, nuclear and particle physics, astrophysics, isotope separations etc.. Abstracts available on CD-Rom only. (J.S.)

  4. Stable isotope research pool inventory

    International Nuclear Information System (INIS)

    1982-01-01

    This report contains a listing of electromagnetically separated stable isotopes which are available for distribution within the United States for nondestructive research use from the Oak Ridge National Laboratory on a loan basis. This inventory includes all samples of stable isotopes in the Material Research Collection and does not designate whether a sample is out on loan or in reprocessing. For some of the high abundance naturally occurring isotopes, larger amounts can be made available; for example, Ca-40 and Fe-56

  5. Stable carbon isotopes in high-productive littoral areas of Lake Constance

    International Nuclear Information System (INIS)

    Chondrogianni, C.

    1992-01-01

    The investigation attempted to extend understanding of C fractionation in aquatic systems and to facilitate the interpretation of palaeolimnological isotope data. Particular interest was taken in the aspect of bicarbonate assimilation at high productivity and in the exchange processes between water and atmosphere. Littoral areas of lakes were chosen as areas of investigation as they offer a high-productivity environment with large populations of submersed macrophytes and periphytes. To get a better picture of the factors influencing C fractionation, litteral and pellagial regions were compared on the one hand and a mesotrophic (Ueberlingersee) and a eutrophic (Gnadensee) lake section on the other hand. Further factors of differentiation between the two lake parts were: Volume, the proportional share of the litteral area, and water exchange. Two main fields of interest were investigated: - Determination of the C isotope ratio (δ 13 C) in the dissolved bicarbonate of water in the sediments of a single year for the purpose of calibrating its fractionation in the basis of the present chemical and physical status of the lake water (water programme). - Determination of δ 13 C in selected carbonate components from sedimentary cores in order to find out about palaeolimnological events in the areas of investigation (sediment programme). (orig.) [de

  6. New manuscript guidelines for the reporting of stable hydrogen, carbon, and oxygen isotope-ratio data

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1995-10-01

    To eliminate possible confusion in the reporting of isotopic abundances on non-corresponding scales, the Commission on Atomic Weights and Isotopic Abundances recommended at the 37{sup th} General Assembly at Lisbon, Portugal that (i) {sup 2}H/{sup 1}H relative ratios of all substances be expressed relative to VSMOW (Vienna Standard Mean Ocean Water) on a scale such that {sup 2}H/{sup 1}H of SLAP (Standard Light Antartic Precipitation) is 0.572 times that of VSMOW, (ii) {sup 13}C/{sup 12}C relative ratios of all substances be expressed relative to VPDB (Vienna Peedee belemnite) on a scale such that {sup 13}C/{sup 12}C of NBS 19 carbonate is 1.00195 times that of VPDB, and (iii) {sup 18}O/{sup 16}O ratios of all substances be expressed relative to either VSMOW or VPDB on scales such that {sup 18}O/{sup 16}O of SLAP is 0.9445 times that of VSMOW. (Author)

  7. Stable calcium isotope composition of a pedogenic carbonate in forested ecosystem: the case of the needle fibre calcite (NFC).

    Science.gov (United States)

    Milliere, Laure; Verrecchia, Eric; Gussone, Nikolaus

    2014-05-01

    shape of NFC could be ascribed to a growth related to fungal organic molecules or potentially inside fungal hyphae. Three microscopic morphologies of NFC, previously defined (Milliere et al., 2011a), have been also examined in order to trace the evolution of the NFC inside the soil porosity. The Ca isotope composition of the simple needles, which are supposed to be the original form of NFC are the less fractionated compared to the soil solution, whereas the Ca isotope composition of the two other microscopic morphologies, namely the simple needle with nanofibres and the simple needle with overgrowths, are more fractionated, like the LCC, indicating potentially the influence of biogenic processes in the formation of the simple needles. Milliere L, Hasinger O, Bindschedler S, Cailleau G, Spangenberg JE, Verrecchia EP. 2011a. Stable carbon and oxygen isotopic signatures of pedogenic needle fibre calcite. Geoderma 161, 74-87.

  8. petrography, compositional characteristics and stable isotope ...

    African Journals Online (AJOL)

    PROF EKWUEME

    Subsurface samples of the predominantly carbonate Ewekoro Formation, obtained from Ibese core hole within the Dahomey basin were used in this study. Investigations entail petrographic, elemental composition as well as stable isotopes (carbon and oxygen) geochemistry in order to deduce the different microfacies and ...

  9. Application of carbon and hydrogen stable isotope analyses to detect exogenous citric acid in Japanese apricot liqueur.

    Science.gov (United States)

    Akamatsu, Fumikazu; Oe, Takaaki; Hashiguchi, Tomokazu; Hisatsune, Yuri; Kawao, Takafumi; Fujii, Tsutomu

    2017-08-01

    Japanese apricot liqueur manufacturers are required to control the quality and authenticity of their liqueur products. Citric acid made from corn is the main acidulant used in commercial liqueurs. In this study, we conducted spiking experiments and carbon and hydrogen stable isotope analyses to detect exogenous citric acid used as an acidulant in Japanese apricot liqueurs. Our results showed that the δ 13 C values detected exogenous citric acid originating from C 4 plants but not from C 3 plants. The δ 2 H values of citric acid decreased as the amount of citric acid added increased, whether the citric acid originated from C 3 or C 4 plants. Commercial liqueurs with declared added acidulant provided higher δ 13 C values and lower δ 2 H values than did authentic liqueurs and commercial liqueurs with no declared added acidulant. Carbon and hydrogen stable isotope analyses are suitable as routine methods for detecting exogenous citric acid in Japanese apricot liqueur. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Source characterization using compound composition and stable carbon isotope ratio of PAHs in sediments from lakes, harbor, and shipping waterway

    International Nuclear Information System (INIS)

    Kim, Moonkoo; Kennicutt, Mahlon C.; Qian, Yaorong

    2008-01-01

    Molecular compositions and compound specific stable carbon isotope ratios of polycyclic aromatic hydrocarbons (PAH) isolated from sediments were used to characterize possible sources of contamination at an urban lake, a harbor, a shipping waterway, and a relatively undisturbed remote lake in the northwest United States. Total PAH concentrations in urban lake sediments ranged from 66.0 to 16,500 μg g -1 dry wt. with an average of 2600 μg g -1 , which is ∼ 50, 100, and 400 times higher on average than PAH in harbor (48 μg g -1 on average), shipping waterway (26 μg g -1 ), and remote lake (7 μg g -1 ) sediments, respectively. The PAH distribution patterns, methyl phenanthrene/phenanthrene ratios, and a pyrogenic index at the sites suggest a pyrogenic origin for PAHs. Source characterization using principal component analysis and various molecular indices including C2-dibenzothiophenes/C2-phenanthrenes, C3-dibenzothiophenes/C3-phenanthrenes, and C2-chrysenes/C2-phenanthrenes ratios, was able to differentiate PAH deposited in sediments from the four sites. The uniqueness of the source of the sediment PAHs from urban lake was also illustrated by compound specific stable carbon isotope analysis. It was concluded that urban lake sediments are accumulating PAH from sources that are unique from contamination detected at nearby sites in the same watershed

  11. Variation in carbon and nitrogen stable isotope ratios in flight feathers of a moulting White-bellied Sunbird Cinnyris talatala

    CSIR Research Space (South Africa)

    Symes, CT

    2011-11-01

    Full Text Available The authors measured d13C and d15N isotope signatures in flight feathers of a White-bellied Sunbird to assess the value of using stable isotopes of feathers in avian dietary studies. Significant variation in d13C and d15N isotope values of flight...

  12. Stable carbon isotope fractionation of organic cyst-forming dinoflagellates: Evaluating the potential for a CO2 proxy

    Science.gov (United States)

    Hoins, Mirja; Van de Waal, Dedmer B.; Eberlein, Tim; Reichart, Gert-Jan; Rost, Björn; Sluijs, Appy

    2015-07-01

    Over the past decades, significant progress has been made regarding the quantification and mechanistic understanding of stable carbon isotope fractionation (13C fractionation) in photosynthetic unicellular organisms in response to changes in the partial pressure of atmospheric CO2 (pCO2). However, hardly any data is available for organic cyst-forming dinoflagellates while this is an ecologically important group with a unique fossil record. We performed dilute batch experiments with four harmful dinoflagellate species known for their ability to form organic cysts: Alexandrium tamarense, Scrippsiella trochoidea, Gonyaulax spinifera and Protoceratium reticulatum. Cells were grown at a range of dissolved CO2 concentrations characterizing past, modern and projected future values (∼5-50 μmol L-1), representing atmospheric pCO2 of 180, 380, 800 and 1200 μatm. In all tested species, 13C fractionation depends on CO2 with a slope of up to 0.17‰ (μmol L)-1. Even more consistent correlations were found between 13C fractionation and the combined effects of particulate organic carbon quota (POC quota; pg C cell-1) and CO2. Carbon isotope fractionation as well as its response to CO2 is species-specific. These results may be interpreted as a first step towards a proxy for past pCO2 based on carbon isotope ratios of fossil organic dinoflagellate cysts. However, additional culture experiments focusing on environmental variables other than pCO2, physiological underpinning of the recorded response, testing for possible offsets in 13C values between cells and cysts, as well as field calibration studies are required to establish a reliable proxy.

  13. Stable isotope tracing of trout hatchery carbon to sediments and foodwebs of limestone spring creeks

    Energy Technology Data Exchange (ETDEWEB)

    Hurd, Todd M. [Department of Biology, Shippensburg University, 1871 Old Main Dr., Shippensburg, PA 17257 (United States)], E-mail: tmhurd@ship.edu; Jesic, Slaven; Jerin, Jessica L.; Fuller, Nathan W.; Miller, David [Department of Biology, Shippensburg University, 1871 Old Main Dr., Shippensburg, PA 17257 (United States)

    2008-11-01

    Limestone springs support productive ecosystems and fisheries, yet aquaculture may modify or impair these ecosystems. We determined trout hatchery organic contribution to spring creek sediments and foodwebs with natural abundance stable isotope methods. Hatchery feed, waste, and trout were significantly enriched in {delta}{sup 13}C relative to autotrophs and wild fish. Spring creek sediments were enriched in {delta}{sup 13}C toward the hatchery endmember relative to reference streams without hatcheries and relative to a larger larger-order, spring-influenced stream. Contribution of hatchery C to spring creek sediments was greatest during March and associated with greatest sediment %C. Contribution of hatchery C to pollution-tolerant isopod diet was 39-51% in a stream receiving limestone spring water via hatchery effluent. Isopods of one spring creek also relied on hatchery-derived C within one month of hatchery closure. Four years later, less pollution pollution-tolerant amphipods dominated and consumed non-vascular over vascular autotrophs (86%). Isopods of a second spring creek with an active hatchery did not appear to be using hatchery matter directly, but were enriched in {delta}{sup 34}S relative to a spring creek tributary with no hatchery influence. Isopods in both of these streams were relatively enriched in {delta}{sup 15}N, indicating general nutrient enrichment from surrounding agricultural land use. The contribution of hatchery vs. wild fish in diet of herons and egrets was traced with {delta}{sup 13}C of guano. These birds were strongly dependent on stocked trout in a spring creek with a recently closed state trout hatchery, and also near another large, state-run hatchery. Heron dependence on hatchery fish in the spring creek decreased with time since hatchery closure. Use of stable isotope natural abundance techniques in karst spring creeks can reveal stream impairment due to aquaculture, specific C sources to bio-indicating consumers, losses of

  14. Stable carbon isotope cycling in mobile coastal muds of Amapá, Brazil

    Science.gov (United States)

    Zhu, Zhongbin; Aller, Robert C.; Mak, John

    2002-10-01

    Approximately 10% of the sediment delivered by the Amazon River moves northwest along the coast of Amapá, Brazil, initiating the Guianas mobile mud belt. Amapá coastal muds generally have a two-layer transport structure and are characterized by highly non-steady-state sedimentation. Isotopic compositions of pore water ∑CO 2 and solid phase C org demonstrate that remineralization in the surficial mobile zone (˜0.3-1 m thick) is dominated by terrestrial sources at sites in proximity to the mangrove fringe (˜1-2 m water depth), and marine (plus possible carbonate dissolution) sources further offshore (˜21 km, ˜7 m depth). The net δ13C of ∑CO 2 produced and C org remineralized is ˜-26‰ and -25.9‰, respectively inshore, and ˜-14‰ and -18.6‰, respectively offshore (compared to average terrestrial and marine C org end members of -28‰ and -20‰). Efficient remineralization in the suboxic mobile zone lowers particle surface loading of C org from ˜0.35 mg C m -2 in the Amazon delta topset to ˜0.13-0.16 along Amapá. Sequential, temperature-dependent extractions were used to operationally fractionate inorganic C pools. Authigenic carbonates, mostly siderite and mixed Ca, Mg, Fe, Mn-carbonates, dominate sediment inorganic C (˜50-200 μmol g -1). The mass weighted δ13C of carbonates, ˜-15‰ to -19‰, is relatively restricted in range compared to pore water ∑CO 2, implying most precipitation in the reactive mobile surface sediments. Periodic mixing with bottom seawater and/or dissolution of biogenic carbonates in the surficial layer shift δ13C values of pore water to heavier values than C org reactant sources. At one offshore site (˜7 m), about 22% of pore water ∑CO 2 has undergone reduction during methanogenesis below the mobile surface zone, extracting ∑CO 2 with δ13C˜-90‰ and leaving a residual δ13C˜-0.37‰. Diagenetic processes in the suboxic mobile mud zone dominate C remineralization and storage along the coast of Amapá.

  15. Stable carbon, oxygen, and nitrogen, isotope analysis of plants from a South Asian tropical forest: Implications for primatology.

    Science.gov (United States)

    Roberts, Patrick; Blumenthal, Scott A; Dittus, Wolfgang; Wedage, Oshan; Lee-Thorp, Julia A

    2017-06-01

    Stable isotope analysis of primate tissues in tropical forest contexts is an increasingly popular means of obtaining information about niche distinctions among sympatric species, including preferences in feeding height, forest canopy density, plant parts, and trophism. However, issues of equifinality mean that feeding height, canopy density, as well as the plant parts and plant species consumed, may produce similar or confounding effects. With a few exceptions, researchers have so far relied largely on general principles and/or limited plant data from the study area as references for deducing the predominant drivers of primate isotope variation. Here, we explore variation in the stable carbon (δ 13 C), nitrogen (δ 15 N), and oxygen (δ 18 O) isotope ratios of 288 plant samples identified as important to the three primate species from the Polonnaruwa Nature Sanctuary, Sri Lanka, relative to plant part, season, and canopy height. Our results show that plant part and height have the greatest effect on the δ 13 C and δ 18 O measurements of plants of immediate relevance to the primates, Macaca sinica, Semnopithecus priam thersites, and Trachypithecus vetulus, living in this monsoonal tropical forest. We find no influence of plant part, height or season on the δ 15 N of measured plants. While the plant part effect is particularly pronounced in δ 13 C between fruits and leaves, differential feeding height, and plant taxonomy influence plant δ 13 C and δ 18 O differences in addition to plant organ. Given that species composition in different regions and forest types will differ, the results urge caution in extrapolating general isotopic trends without substantial local baselines studies. © 2017 Wiley Periodicals, Inc.

  16. Using the stable carbon and nitrogen isotope compositions of vervet monkeys (Chlorocebus pygerythrus to examine questions in ethnoprimatology.

    Directory of Open Access Journals (Sweden)

    James E Loudon

    Full Text Available This study seeks to understand how humans impact the dietary patterns of eight free-ranging vervet monkey (Chlorocebus pygerythrus groups in South Africa using stable isotope analysis. Vervets are omnivores that exploit a wide range of habitats including those that have been anthropogenically-disturbed. As humans encroach upon nonhuman primate landscapes, human-nonhuman primate interconnections become increasingly common, which has led to the rise of the field of ethnoprimatology. To date, many ethnoprimatological studies have examined human-nonhuman primate associations largely in qualitative terms. By using stable carbon (δ13C and nitrogen (δ15N isotope analysis, we use quantitative data to understand the degree to which humans impact vervet monkey dietary patterns. Based on initial behavioral observations we placed the eight groups into three categories of anthropogenic disturbance (low, mid, and high. Using δ13C and δ15N values we estimated the degree to which each group and each anthropogenically-disturbed category was consuming C4 plants (primarily sugar cane, corn, or processed foods incorporating these crops. δ13C values were significantly different between groups and categories of anthropogenic-disturbance. δ15N values were significantly different at the group level. The two vervet groups with the highest consumption of C4 plants inhabited small nature reserves, appeared to interact with humans only sporadically, and were initially placed in the mid level of anthropogenic-disturbance. However, further behavioral observations revealed that the high δ13C values exhibited by these groups were linked to previously unseen raiding of C4 crops. By revealing these cryptic feeding patterns, this study illustrates the utility of stable isotopes analysis for some ethnoprimatological questions.

  17. Analysis of carbon stable isotope to determine the origin and migration of gaseous hydrocarbon in the Brazilian sedimentary basins

    International Nuclear Information System (INIS)

    Takaki, T.; Rodrigues, R.

    1986-01-01

    The carbon isotopic composition of natural gases to determine the origin and gaseous hydrocarbon migration of Brazilian sedimentar basins is analysed. The carbon isotopic ratio of methane from natural gases depends on the process of gas formation and stage of organic matter maturation. In the geochemical surface exploration the biogenic gases are differentiated from thermogenic gases, because the last one is isotopically heavier. As the isotopic composition of methane has not changed during migration, the migrated gases from deeper and more mature source rocks are identified by its relative 13 C enrichment. The methane was separated from chromatography and and the isotopic analysis was done with mass spectrometer. (M.C.K.) [pt

  18. A Regional Stable Carbon Isotope Dendro-Climatology from the South African Summer Rainfall Area.

    Science.gov (United States)

    Woodborne, Stephan; Gandiwa, Patience; Hall, Grant; Patrut, Adrian; Finch, Jemma

    2016-01-01

    Carbon isotope analysis of four baobab (Adansonia digitata L.) trees from the Pafuri region of South Africa yielded a 1000-year proxy rainfall record. The Pafuri record age model was based on 17 radiocarbon dates, cross correlation of the climate record, and ring structures that were presumed to be annual for two of the trees. Here we present the analysis of five additional baobabs from the Mapungubwe region, approximately 200km west of Pafuri. The Mapungubwe chronology demonstrates that ring structures are not necessarily annually formed, and accordingly the Pafuri chronology is revised. Changes in intrinsic water-use efficiency indicate an active response by the trees to elevated atmospheric CO2, but this has little effect on the environmental signal. The revised Pafuri record, and the new Mapungubwe record correlate significantly with local rainfall. Both records confirm that the Medieval Warm Period was substantially wetter than present, and the Little Ice Age was the driest period in the last 1000 years. Although Mapungubwe is generally drier than Pafuri, both regions experience elevated rainfall peaking between AD 1570 and AD 1620 after which dry conditions persist in the Mapungubwe area until about AD 1840. Differences between the two records correlate with Agulhas Current sea-surface temperature variations suggesting east/west displacement of the temperate tropical trough system as an underlying mechanism. The Pafuri and Mapungubwe records are combined to provide a regional climate proxy record for the northern summer rainfall area of southern Africa.

  19. A Regional Stable Carbon Isotope Dendro-Climatology from the South African Summer Rainfall Area.

    Directory of Open Access Journals (Sweden)

    Stephan Woodborne

    Full Text Available Carbon isotope analysis of four baobab (Adansonia digitata L. trees from the Pafuri region of South Africa yielded a 1000-year proxy rainfall record. The Pafuri record age model was based on 17 radiocarbon dates, cross correlation of the climate record, and ring structures that were presumed to be annual for two of the trees. Here we present the analysis of five additional baobabs from the Mapungubwe region, approximately 200km west of Pafuri. The Mapungubwe chronology demonstrates that ring structures are not necessarily annually formed, and accordingly the Pafuri chronology is revised. Changes in intrinsic water-use efficiency indicate an active response by the trees to elevated atmospheric CO2, but this has little effect on the environmental signal. The revised Pafuri record, and the new Mapungubwe record correlate significantly with local rainfall. Both records confirm that the Medieval Warm Period was substantially wetter than present, and the Little Ice Age was the driest period in the last 1000 years. Although Mapungubwe is generally drier than Pafuri, both regions experience elevated rainfall peaking between AD 1570 and AD 1620 after which dry conditions persist in the Mapungubwe area until about AD 1840. Differences between the two records correlate with Agulhas Current sea-surface temperature variations suggesting east/west displacement of the temperate tropical trough system as an underlying mechanism. The Pafuri and Mapungubwe records are combined to provide a regional climate proxy record for the northern summer rainfall area of southern Africa.

  20. RNA–Stable-Isotope Probing Shows Utilization of Carbon from Inulin by Specific Bacterial Populations in the Rat Large Bowel

    Science.gov (United States)

    Lawley, Blair; Munro, Karen; Sims, Ian M.; Lee, Julian; Butts, Christine A.; Roy, Nicole

    2014-01-01

    Knowledge of the trophisms that underpin bowel microbiota composition is required in order to understand its complex phylogeny and function. Stable-isotope (13C)-labeled inulin was added to the diet of rats on a single occasion in order to detect utilization of inulin-derived substrates by particular members of the cecal microbiota. Cecal digesta from Fibruline-inulin-fed rats was collected prior to (0 h) and at 6, 12, 18 and 24 h following provision of the [13C]inulin diet. RNA was extracted from these cecal specimens and fractionated in isopycnic buoyant density gradients in order to detect 13C-labeled nucleic acid originating in bacterial cells that had metabolized the labeled dietary constituent. RNA extracted from specimens collected after provision of the labeled diet was more dense than 0-h RNA. Sequencing of 16S rRNA genes amplified from cDNA obtained from these fractions showed that Bacteroides uniformis, Blautia glucerasea, Clostridium indolis, and Bifidobacterium animalis were the main users of the 13C-labeled substrate. Culture-based studies of strains of these bacterial species enabled trophisms associated with inulin and its hydrolysis products to be identified. B. uniformis utilized Fibruline-inulin for growth, whereas the other species used fructo-oligosaccharide and monosaccharides. Thus, RNA–stable-isotope probing (RNA-SIP) provided new information about the use of carbon from inulin in microbiota metabolism. PMID:24487527

  1. Stable carbon and nitrogen isotope variation in the northern lampfish and Neocalanus, marine survival rates of pink salmon, and meso-scale eddies in the Gulf of Alaska

    Science.gov (United States)

    Kline, Thomas C., Jr.

    2010-10-01

    Northern lampfish (NLF), Stenobrachius leucopsarus (Myctophidae), the dominant pelagic fish taxon of the subarctic North Pacific Ocean, were sampled opportunistically in MOCNESS tows made on continental slope waters of the Gulf of Alaska (GOA) as well as in deep areas of Prince William Sound (PWS) during 1997-2006. The overall mean whole-body lipid-corrected stable carbon isotope value of NLF from the GOA was -21.4 (SD = 0.7) whereas that from PWS was -19.5 (SD = 0.9). This pattern is similar to that observed for late feeding stage Neocalanus cristatus copepods thus confirming a mean cross-shelf carbon stable isotope gradient. As well, there was a statistically significant positive correlation between the considerable temporal variation in the monthly mean carbon stable isotope composition of GOA Neocalanus and GOA NLF ( r = 0.69, P food chain length whereas carbon stable isotopes reflect organic carbon production. The carbon stable isotope values of NLF, measured in May, were positively correlated to marine survival rate of PWS hatchery salmon cohorts entering the marine environment the same year ( r = 0.84, P < 0.001). The carbon stable isotope values for Neocalanus in May were also positively correlated to salmon marine survival ( r = 0.82, P < 0.001). Processes thus manifested through the carbon stable isotope value of biota from the continental slope more closely predicted marine survival rate than that of the salmon themselves. The incipient relationships suggested by the correlations are consistent with the hypothesis that exchange between coastal and oceanic waters in the study area is driven by meso-scale eddies. These eddies facilitate the occurrence of slope phytoplankton blooms as well as drive oceanic zooplankton subsidies into coastal waters. The strong as well as more significant correlations of salmon marine survival rate to NLF as well as slope Neocalanus carbon stable isotope values point to processes taking place at the slope (i.e., interactions

  2. Pharmaceuticals labelled with stable isotopes

    International Nuclear Information System (INIS)

    Krumbiegel, P.

    1986-11-01

    The relatively new field of pharmaceuticals labelled with stable isotopes is reviewed. Scientific, juridical, and ethical questions are discussed concerning the application of these pharmaceuticals in human medicine. 13 C, 15 N, and 2 H are the stable isotopes mainly utilized in metabolic function tests. Methodical contributions are given to the application of 2 H, 13 C, and 15 N pharmaceuticals showing new aspects and different states of development in the field under discussion. (author)

  3. Dynamics of Carbonates in Soils under Different Land Use in Forest-Steppe Area of Russia Using Stable and Radiogenic Carbon Isotope Data

    Directory of Open Access Journals (Sweden)

    Olga Khokhlova

    2018-04-01

    Full Text Available The work is aimed at the analysis of carbonate dynamics in soils under different land use. The studied area is located in the forest steppe - of the Central Russian Upland. Soils were sampled at four sites: a broadleaf forest, an adjacent 50-year continuously cropped field including plots under a corn monoculture, bare fallow, and a crop rotation area with a clean fallow every fourth year. The carbonates’ morphology, their chemical composition, as well as their stable and radiogenic isotopes of carbon were studied. Clear-cut distinctions were found in the carbonate distribution throughout the profiles in the microstructure of carbonate pedofeatures, carbon isotopic composition, and radiocarbon age of carbonates between the pairs of the plots as follows: the bare fallow and the crop rotation on the one hand, and the corn monoculture and forest on the other. The distinctions are commonly assumed to result from repeating upward water fluxes, which are different in the bare soils and those with plant cover. A clear difference occurred in the hydrothermal regime for soils with and without plant cover, and was found to be the key factor of the observed differences. In addition, in soils under plant cover, the carbonate migration upward occurs due to process of transpiration, whereas in soils devoid of plants, it occurs due to physical evaporation.

  4. In-situ studies of microbial CH4 oxidation efficiency in Arctic wetland soils. Applications of stable carbon isotopes

    International Nuclear Information System (INIS)

    Preuss, Inken-Marie

    2013-01-01

    Arctic wetland soils are significant sources of the climate-relevant trace gas methane (CH 4 ). The observed accelerated warming of the Arctic is expected to cause deeper permafrost thawing followed by increased carbon mineralization and CH 4 formation in water-saturated permafrost-affected tundra soils thus creating a positive feedback to climate change. Aerobic CH 4 oxidation is regarded as the key process reducing CH 4 emissions from wetlands, but quantification of turnover rates has remained difficult so far. This study improved the in-situ quantification of microbial CH 4 oxidation efficiency in arctic wetland soils in Russia's Lena River Delta based on stable isotope signatures of CH 4 . In addition to the common practice of determining the stable isotope fractionation during oxidation, additionally the fractionation effect of diffusion, an important gas transport mechanism in tundra soils, was investigated for both saturated and unsaturated conditions. The isotopic fractionation factors α ox and α diff were used to calculate the CH 4 oxidation efficiency from the CH 4 stable isotope signatures of wet polygonal tundra soils of different hydrology. Further, the method was used to study the short-term effects of temperature increase with a climate manipulation experiment. For the first time, the stable isotope fractionation of CH 4 diffusion through water-saturated soils was determined with α diff = 1.001 ± 0.0002 (n = 3). CH 4 stable isotope fractionation during diffusion through air-filled pores of the investigated polygonal tundra soils was α diff = 1.013 ± 0.003 (n = 18). For the studied sites the fractionation factor for diffusion under saturated conditions α diff = 1.001 seems to be of utmost importance for the quantification of the CH 4 oxidation efficiency, since most of the CH 4 is oxidized in the saturated part at the aerobic-anaerobic interface. Furthermore, it was found that α ox differs widely between sites and horizons (mean α ox = 1

  5. Stable Carbon Isotopes (δ 13C) in Coral Skeletons: Experimental Approach and Applications for Paleoceanography

    Science.gov (United States)

    Grottoli, A. G.

    2004-12-01

    Scleractinian corals obtain fixed carbon via photosynthesis by their endosymbiotic algae (zooxanthellae) and via hetertrophy (injestion of zooplankton, δ 13C ≈ -17 to -22‰ ). Carbon dioxide (CO2) used for photosynthesis is obtained from seawater (δ 13C ≈ 0%) or from respired CO2 within the coral host. The δ 13C of the carbon used in the formation of the underlying coral skeleton is fractionated as a result of both of these metabolic processes. Here I have pooled evidence from several field and tank experiments on the effect of photosynthesis and heterotrophy of coral skeletal δ 13C. In the experiments, decreases in light levels due to shading or depth resulted in a significant decrease in skeletal δ 13C in all species studied (Pavona gigantea, Pavona clavus, Porites compressa). Decreases in photosynthesis in bleached corals also resulted in a decrease in skeletal δ 13C compared to non-bleached corals growing under the same conditions and at the same location. Skeletal δ 13C also decreased at higher than normal light levels most likely due to photoinhibition. Thus, decreases in photosynthesis due to reduced light levels, due to bleaching-induced decreases in chlorophyll a concentrations, or due to photodamage-induced decreases in functional cholorphyll a, results in significant δ 13C decreases. Comprehensive interpretation of all of the data showed that changes in photosynthesis itself can drive the changes in δ 13C. In field experiments, the addition of natural concentrations of zooplankton to the diet resulted in decreases in skeletal δ 13C. Such a decrease was more pronounced with depth and in P. gigantea compared to P. clavus. In situ feeding experiments have since confirmed these findings. However under tank conditions with unaturally high feeding rates, enhanced nitrogen supply in the diet can disrupt the coral-algal symbiosis, stimlate zooxanthellae growth and photosynthesis, and cause an incrase in skeletal δ 13C. It is proposed that under

  6. [Spatial variation of soil carbon and stable isotopes in the southern margin desert of Junggar Basin, China].

    Science.gov (United States)

    Wang, Na; Xu, Wen Qiang; Xu, Hua Jun; Feng, Yi Xing; Li, Chao Fan

    2017-07-18

    The southern margin desert of Junggar Basin in the central arid region of Asia was selec-ted as the study area. To gain insight into the distribution characteristic of stable carbon isotope and the relationship between the change of soil carbon and the distance to oasis of soil organic carbon (SOC) and soil inorganic carbon (SIC), three belt transects were set according to the distance between the desert and the oasis in edge, middle and hinterland of the desert respectively, and collected the soil profile samples with depth of 2 m. The results indicated that the SOC content reduced with the soil depth, and the variation with the distance to oasis was the edge> the middle> the hinterland. The δ 13 C value of SOC varied in the range of -21.92‰ to -17.41‰, and decreased with the depth; the range in the middle and hinterland was -25.20‰ to -19.30‰, and increased then declined with the depth. Therefore, we could infer that the C3 plants played a dominant role in the central of desert, and had experienced the succession from C3 plants to C4 plants. The average content of SIC was 38.98 g·kg -1 in the edge of desert, which was about 6.01 folds as large as the content in the hinterland. This indicated that a large number of SIC with 0-2 m depth were clustered in the edge of the desert. The δ 13 C value of SIC increased first then decreased with the soil depth, and enriched in the bottom layer, which was mainly affected by the original carbonate content and soil carbon dioxide.

  7. Investigation of the microbial metabolism of carbon dioxide and hydrogen in the kangaroo foregut by stable isotope probing

    OpenAIRE

    Godwin, Scott; Kang, Alicia; Gulino, Lisa-Maree; Manefield, Mike; Gutierrez-Zamora, Maria-Luisa; Kienzle, Marco; Ouwerkerk, Diane; Dawson, Kerri; Klieve, Athol V

    2014-01-01

    Kangaroos ferment forage material in an enlarged forestomach analogous to the rumen, but in contrast to ruminants, they produce little or no methane. The objective of this study was to identify the dominant organisms and pathways involved in hydrogenotrophy in the kangaroo forestomach, with the broader aim of understanding how these processes are able to predominate over methanogenesis. Stable isotope analysis of fermentation end products and RNA stable isotope probing (RNA-SIP) were used to ...

  8. The exchange of acetaldehyde between plants and the atmosphere: Stable carbon isotope and flux measurements

    Science.gov (United States)

    Jardine, Kolby Jeremiah

    The exchange of acetaldehyde between plant canopies and the atmosphere may significantly influence regional atmospheric chemistry and plant metabolism. While plants are known to both produce and consume acetaldehyde, the exchange of this compound with forested ecosystems is complicated by physical, biological, and chemical processes that range from being poorly understood to completely unknown. This precludes a quantitative understanding of acetaldehyde exchange rates between the atmosphere and the biosphere. In this study, the processes controlling the exchange of acetaldehyde with plant canopies was investigated using concentration, flux, and natural abundance 13C measurements of gas phase acetaldehyde from individual plants, soils, and entire ecosystems. Although previously only considered important in anoxic tissues, it was discovered that acetaldehyde is produced and consumed in leaves through ethanolic fermentation coupled to the pyruvate dehydrogenase bypass system under normal aerobic conditions. These coupled pathways determine the acetaldehyde compensation point, a major factor controlling its exchange with the atmosphere. Carbon isotope analysis suggests a new pathway for acetaldehyde production from plants under stress involving the peroxidation of membrane fatty acids. This pathway may be a major source of acetaldehyde to the atmosphere from plants under biotic and abiotic stresses. Plant stomata were found to be the dominant pathway for the exchange of acetaldehyde with the atmosphere with stomatal conductance influencing both emission and uptake fluxes. In addition, increasing temperature and solar radiation was found to increase the compensation point by increasing the rates of acetaldehyde production relative to consumption. Under ambient conditions, bare soil was neutral to the exchange of acetaldehyde while senescing and decaying leaves were found to be strong source of acetaldehyde to the atmosphere due to increased decomposition processes and

  9. Simultaneous stable carbon isotopic analysis of wine glycerol and ethanol by liquid chromatography coupled to isotope ratio mass spectrometry.

    Science.gov (United States)

    Cabañero, Ana I; Recio, Jose L; Rupérez, Mercedes

    2010-01-27

    A novel procedure was established for the simultaneous characterization of wine glycerol and ethanol (13)C/(12)C isotope ratio, using liquid chromatography/isotope ratio mass spectrometry (LC-IRMS). Several parameters influencing separation of glycerol and ethanol from wine matrix were optimized. Results obtained for 35 Spanish samples exposed no significant differences and very strong correlations (r = 0.99) between the glycerol (13)C/(12)C ratios obtained by an alternative method (gas chromatography/isotope ratio mass spectrometry) and the proposed new methodology, and between the ethanol (13)C/(12)C ratios obtained by the official method (elemental analyzer/isotope ratio mass spectrometry) and the proposed new methodology. The accuracy of the proposed method varied from 0.01 to 0.19 per thousand, and the analytical precision was better than 0.25 per thousand. The new developed LC-IRMS method it is the first isotopic method that allows (13)C/(12)C determination of both analytes in the same run directly from a liquid sample with no previous glycerol or ethanol isolation, overcoming technical difficulties associated with complex sample treatment and improving in terms of simplicity and speed.

  10. Origin of particulate organic carbon in the marine atmosphere as indicated by it stable carbon isotopic composition

    International Nuclear Information System (INIS)

    Chesselet, R.; Fontugne, M.; Buat-Menard, P.; Ezat, U.; Lambert, C.E.

    1981-01-01

    Organic carbon concentration and isotopic composition were determined in samples of atmospheric particulate matter collected in 1979 at remote marine locations (Enewetak atoll, Sargasso Sea) during the SEAREX (Sea-Air Exchange) program field experiments. Atmospheric Particulate Organic Carbon (POC) concentrations were found to be in the range of 0.3 to 1.2 mg. m -3 , in agreement with previous literature data. The major mass of POC was found on the smallest particles (r 13 C/ 12 C of the small particles is close to the one expected (d 13 C = 26 +- 2 0 //sub infinity/) for atmospheric POC of continental origin. For all the samples analysed so far, it appears that more than 80% of atmospheric POC over remote marine areas is of continental origin. This can be explained either by long-range transport of small sized continental organic aserosols or by the production of POC in the marine atmosphere from a vapor phase organic carbon pool of continental origin. The POC in the large size fraction of marine aerosols ( 13 C = -21 +- 2 0 / 00 ) for POC associated with sea-salt droplets transported to the marine atmosphere

  11. Stable-isotope studies

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    Structures of bacteriochlorophyll b and the Krasnovskii photoreduction products of chlorophyll a are given. All 55 13 C and 4 15 N NMR transitions in chlorophyl a and its magnesium-free derivative pheophytin a were assigned. ESR of triplet states of chlorophylls a, b, c/sub z/, and c 2 and bacteriochlorophyll a are reported. Experiments in the cultivation of 13 C-enriched morning glory plants indicated that the isotope enrichment can produce observable morphological changes. (U.S.)

  12. Marine subsidies of island communities in the Gulf of California: evidence from stable carbon and nitrogen isotopes

    International Nuclear Information System (INIS)

    Anderson, W.B.; Polis, G.A.

    1998-01-01

    Coastal sites support larger (2 to > 100 x) populations of many consumers than inland sites on islands in the Gulf of California. Previous data suggested that subsidies of energy and nutrients from the ocean allowed large coastal populations. Stable carbon and nitrogen isotopes are frequently used to analyse diet composition of organisms: they are particularly useful to distinguish between diet sources with distinct isotopic signatures, such as marine and terrestrial diets. We analyzed the 13 C and 15 N concentrations of coastal versus inland spiders and scorpions to test the hypothesis that coastal individuals exhibited more strongly marine-based diets than inland individuals. Coastal spiders and scorpions were significantly more enriched in 13 C and 15 N than inland spiders and scorpions, suggesting that the coastal individuals consumed more marine-based foods than their inland counterparts. These patterns existed in both drought years and wet El Nino years. However, the marine influence was stronger in drought years when terrestrial productivity was nearly non-existent, than in wet years when terrestrial productivity increased by an order of magnitude. (au)

  13. Carbonate stable isotope constraints on sources of arsenic contamination in Neogene tufas and travertines of Attica, Greece

    Science.gov (United States)

    Kampouroglou, Evdokia E.; Tsikos, Harilaos; Economou-Eliopoulos, Maria

    2017-11-01

    We presented new C and O isotope data of rockforming calcite in terrestrial carbonate deposits from Neogene basins of Attica (Greece), coupled with standard mineralogical and bulk geochemical results. Whereas both isotope datasets [δ18O from -8.99 to -3.20‰(VPDB); δ13C from -8.17 to +1.40‰(VPDB)] could be interpreted in principle as indicative of a meteoric origin, the clear lack of a statistical correlation between them suggests diverse sources for the isotopic variation of the two elements. On the basis of broad correlations between lower carbon isotope data with increasing Fe and bulk organic carbon, we interpreted the light carbon isotope signatures and As enrichments as both derived mainly from a depositional process involving increased supply of metals and organic carbon to the original basins. Periodically augmented biological production and aerobic cycling of organic matter in the ambient lake waters, would have led to the precipitation of isotopically light calcite in concert with elevated fluxes of As-bearing iron oxy-hydroxide and organic matter to the initial terrestrial carbonate sediment. The terrestrial carbonate deposits of Attica therefore represented effective secondary storage reservoirs of elevated As from the adjacent mineralized hinterland; hence these and similar deposits in the region ought to be regarded as key geological candidates for anomalous supply of As to local soils, groundwater and related human activities.

  14. Stable carbon and oxygen isotope ratios of malachite from the patinas of ancient bronze objects

    International Nuclear Information System (INIS)

    Smith, A.W.

    1978-01-01

    13 C/ 12 C and 18 O/ 16 O ratios have been measured for 62 samples of the mineral malachite, taken from the patinas of ancient bronze objects (from Britain, Italy, Libya and China), in order to investigate any possible relationship which may exist between the isotope ratios and the burial conditions of the objects. The results indicate that the isotope ratios are controlled by complex factors related to the climate, vegetation and soil type at the burial site. It is suggested that the technique might be used, given favourable circumstances, in the characterization of patinas and as a possible aid in the detection of synthetic patination. (author)

  15. Engineered in situ bioremediation of a petroleum hydrocarbon-contaminated aquifer: assessment of mineralization based on alkalinity, inorganic carbon and stable carbon isotope balances

    Science.gov (United States)

    Hunkeler, Daniel; Höhener, Patrick; Bernasconi, Stefano; Zeyer, Josef

    1999-04-01

    A concept is proposed to assess in situ petroleum hydrocarbon mineralization by combining data on oxidant consumption, production of reduced species, CH 4, alkalinity and dissolved inorganic carbon (DIC) with measurements of stable isotope ratios. The concept was applied to a diesel fuel contaminated aquifer in Menziken, Switzerland, which was treated by engineered in situ bioremediation. In the contaminated aquifer, added oxidants (O 2 and NO 3-) were consumed, elevated concentrations of Fe(II), Mn(II), CH 4, alkalinity and DIC were detected and the DIC was generally depleted in 13C compared to the background. The DIC production was larger than expected based on the consumption of dissolved oxidants and the production of reduced species. Stable carbon isotope balances revealed that the DIC production in the aquifer originated mainly from microbial petroleum hydrocarbon mineralization, and that geochemical reactions such as carbonate dissolution produced little DIC. This suggests that petroleum hydrocarbon mineralization can be underestimated if it is determined based on concentrations of dissolved oxidants and reduced species.

  16. Stable isotope mass spectrometry in petroleum exploration

    International Nuclear Information System (INIS)

    Mathur, Manju

    1997-01-01

    The stable isotope mass spectrometry plays an important role to evaluate the stable isotopic composition of hydrocarbons. The isotopic ratios of certain elements in petroleum samples reflect certain characteristics which are useful for petroleum exploration

  17. Stable isotopic investigations of early development in extant and fossil chambered cephalopods I. Oxygen isotopic composition of eggwater and carbon isotopic composition of siphuncle organic matter in Nautilus

    Science.gov (United States)

    Crocker, Kimberley C.; DeNiro, Michael J.; Ward, Peter D.

    1985-12-01

    Eggwaters from the chambered cephalopod Nautilus are depleted in both 18O and deuterium relative to ambient seawater. Eggwaters from six other species, including the related chambered cephalopod Sepia, do not show such depletion. These observations indicate that the previously observed step towards more positive δ 18O values in calcium carbonate laid down after Nautilus hatches, relative to carbonate precipitated prior to hatching, can be explained by equilibration of the carbonate with water in the egg before hatching and with seawater after hatching. The presence of an oxygen isotope difference between eggwater and seawater for Nautilus and its absence for Sepia suggest that hatching will be recorded in the δ 18O values of shell carbonates for some but not all extinct and extant chambered cephalopods. The δ 13C values of the organic fraction of the siphuncle in Nautilus do not show any consistent pattern with regard to the time of formation before or after hatching. This observation suggests that the minimum in δ 13C values previously observed for calcium carbonate precipitated after Nautilus hatches is not caused by a change in food sources once the animal becomes free-swimming, as has been suggested.

  18. Stable Isotope Group 1982 progress report

    International Nuclear Information System (INIS)

    Stewart, M.K.

    1983-06-01

    The work of the Stable Isotope Group of the Institute of Nuclear Sciences during 1982, in the fields of isotope geology, isotope hydrology, geochronology, isotope biology and mass spectrometer instrumentation, is described

  19. Stable Isotope Group 1983 progress report

    International Nuclear Information System (INIS)

    Stewart, M.K.

    1984-06-01

    The work of the Stable Isotope Group of the Institute of Nuclear Sciences in the fields of isotope geology, isotope hydrology, geochronology, isotope biology and related fields, and mass spectrometer instrumentation, during 1983, is described

  20. Long-term fertilization alters chemically-separated soil organic carbon pools: Based on stable C isotope analyses

    Science.gov (United States)

    Dou, Xiaolin; He, Ping; Cheng, Xiaoli; Zhou, Wei

    2016-01-01

    Quantification of dynamics of soil organic carbon (SOC) pools under the influence of long-term fertilization is essential for predicting carbon (C) sequestration. We combined soil chemical fractionation with stable C isotope analyses to investigate the C dynamics of the various SOC pools after 25 years of fertilization. Five types of soil samples (0-20, 20-40 cm) including the initial level (CK) and four fertilization treatments (inorganic nitrogen fertilizer, IN; balanced inorganic fertilizer, NPK; inorganic fertilizer plus farmyard manure, MNPK; inorganic fertilizer plus corn straw residue, SNPK) were separated into recalcitrant and labile fractions, and the fractions were analysed for C content, C:N ratios, δ13C values, soil C and N recalcitrance indexes (RIC and RIN). Chemical fractionation showed long-term MNPK fertilization strongly increased the SOC storage in both soil layers (0-20 cm = 1492.4 gC m2 and 20-40 cm = 1770.6 gC m2) because of enhanced recalcitrant C (RC) and labile C (LC). The 25 years of inorganic fertilizer treatment did not increase the SOC storage mainly because of the offsetting effects of enhanced RC and decreased LC, whereas no clear SOC increases under the SNPK fertilization resulted from the fast decay rates of soil C.

  1. Stable isotopes of nitrogen and carbon in an aquatic food web recently invaded by Dreissena polymorpha (Pallas)

    International Nuclear Information System (INIS)

    Mitchell, M.J.; Mills, E.L.; Idrisi, N.; Michener, R.

    1996-01-01

    The carbon and nitrogen concentrations and the stable isotopic compositions (δ 13 C and δ 15 N) of major abiotic and biotic constituents were determined in Oneida Lake, New York. This lake was invaded by the zebra mussel (Dreissena polymorpha) in 1990 and there have been concomitant changes in various biotic and abiotic lake properties. The C (46-49%) and N (12%) concentrations and C:N ratios (3.9-4) of zebra mussel flesh were similar to those reported for other lakes. Trophic positions were reflected in the δ 15 N values for which walleye > gizzard shad and yellow perch > Daphnia spp. and zebra mussel flesh > seston and sediment. There was an average increase of 3.6% 0 15 N per trophic transfer. Results from the δ 13 C analysis suggest that Daphnia spp. were using a distinct source of organic carbon whereas zebra mussel were using the entire seston resource. Only yellow perch showed a significant shift in δ 13 C values (1.1% 0 ), possibly reflecting a shift in a food source and diet from 1992 to 1993. (author). 48 refs., 2 tabs., 2 figs

  2. Biochemical and stable carbon isotope records of mangrove derived organic matter in the sediment cores

    Digital Repository Service at National Institute of Oceanography (India)

    Manju, M.N.; Resmi, P.; RatheeshKumar, C.S.; Gireeshkumar, T.R.; Chandramohanakumar, N.; Joseph, M.M.

    in mangrove sediments. This also confirms the involvement of heterotrophic microorganisms in the organic carbon dynamics of the study area. The bulk elemental ratio (total organic carbon/total nitrogen) varied between 11.39 and 24.14 in the study region...

  3. Measurement of stable carbon isotope ratios of non-methane hydrocarbons and halocarbons

    NARCIS (Netherlands)

    Zuiderweg, A.T.

    2012-01-01

    Within the realm of volatile organic compounds, hydrocarbons and halocarbons form a sizable proportion of carbon input to the atmosphere. Within these compound categories, the light non-methane hydrocarbons (NMHC, two to seven carbon atoms) and monocarbon halocarbons have a special place as these

  4. Stable carbon isotope analysis of fluvial sediment fluxes over two contrasting C(4) -C(3) semi-arid vegetation transitions.

    Science.gov (United States)

    Puttock, Alan; Dungait, Jennifer A J; Bol, Roland; Dixon, Elizabeth R; Macleod, Christopher J A; Brazier, Richard E

    2012-10-30

    Globally, many drylands are experiencing the encroachment of woody vegetation into grasslands. These changes in ecosystem structure and processes can result in increased sediment and nutrient fluxes due to fluvial erosion. As these changes are often accompanied by a shift from C(4) to C(3) vegetation with characteristic δ(13) C values, stable isotope analysis provides a promising mechanism for tracing these fluxes. Input vegetation, surface sediment and fluvially eroded sediment samples were collected across two contrasting C(4) -C(3) dryland vegetation transitions in New Mexico, USA. Isotope ratio mass spectrometric analyses were performed using a Carlo Erba NA2000 analyser interfaced to a SerCon 20-22 isotope ratio mass spectrometer to determine bulk δ(13) C values. Stable isotope analyses of contemporary input vegetation and surface sediments over the monitored transitions showed significant differences (p fluvially eroded sediment from each of the sites, with no significant variation between surface sediment and eroded sediment values. The significant differences in bulk δ(13) C values between sites were dependent on vegetation input. Importantly, these values were robustly expressed in fluvially eroded sediments, suggesting that stable isotope analysis is suitable for tracing sediment fluxes. Due to the prevalent nature of these dryland vegetation transitions in the USA and globally, further development of stable isotope ratio mass spectrometry has provided a valuable tool for enhanced understanding of functional changes in these ecosystems. Copyright © 2012 John Wiley & Sons, Ltd.

  5. Petrography and stable isotope geochemistry of Oligocene-Miocene continental carbonates in south Texas: Implications for paleoclimate and paleoenvironment near sea-level

    Science.gov (United States)

    Godfrey, Conan; Fan, Majie; Jesmok, Greg; Upadhyay, Deepshikha; Tripati, Aradhna

    2018-05-01

    Cenozoic sedimentary rocks in the southern Texas Gulf Coastal Plains contain abundant continental carbonates that are useful for reconstructing terrestrial paleoclimate and paleoenvironment in a region near sea-level. Our field observations and thin section characterizations of the Oligocene and Miocene continental carbonates in south Texas identified three types of pedogenic carbonates, including rhizoliths, carbonate nodules, and platy horizons, and two types of groundwater carbonates, including carbonate-cemented beds and carbonate concretions, with distinctive macromorphologic and micromorphologic features. Based on preservations of authigenic microfabrics and variations of carbon and oxygen isotopic compositions, we suggest these carbonates experienced minimal diagenesis, and their stable isotopic compositions reflect paleoclimate and paleoenvironment in south Texas. Our Oligocene and Miocene carbonate clumped isotope temperatures (T(Δ47)) are 23-28 °C, slightly less than or comparable to the range of modern mean annual and mean warm season air temperature (21-27 °C) in the study area. These T(Δ47) values do not show any dependency on carbonate-type, or trends through time suggesting that groundwater carbonates were formed at shallow depths. These data could indicate that air temperature in south Texas was relatively stable since the early Oligocene. The reconstructed paleo-surface water δ18O values are similar to modern surface water which could indicate that meteoric water δ18O values also remained stable since the early Oligocene. Mean pedogenic carbonate δ13C values increased - 4.6‰ during the late Miocene, most likely reflecting an expansion of C4 grassland in south Texas. This study provides the first mid- and late Cenozoic continental records of paleoclimate and paleoecology in a low-latitude, near sea-level region.

  6. Stable isotopes in Lithuanian bioarcheological material

    Science.gov (United States)

    Skipityte, Raminta; Jankauskas, Rimantas; Remeikis, Vidmantas

    2015-04-01

    Investigation of bioarcheological material of ancient human populations allows us to understand the subsistence behavior associated with various adaptations to the environment. Feeding habits are essential to the survival and growth of ancient populations. Stable isotope analysis is accepted tool in paleodiet (Schutkowski et al, 1999) and paleoenvironmental (Zernitskaya et al, 2014) studies. However, stable isotopes can be useful not only in investigating human feeding habits but also in describing social and cultural structure of the past populations (Le Huray and Schutkowski, 2005). Only few stable isotope investigations have been performed before in Lithuanian region suggesting a quite uniform diet between males and females and protein intake from freshwater fish and animal protein. Previously, stable isotope analysis has only been used to study a Stone Age population however, more recently studies have been conducted on Iron Age and Late medieval samples (Jacobs et al, 2009). Anyway, there was a need for more precise examination. Stable isotope analysis were performed on human bone collagen and apatite samples in this study. Data represented various ages (from 5-7th cent. to 18th cent.). Stable carbon and nitrogen isotope analysis on medieval populations indicated that individuals in studied sites in Lithuania were almost exclusively consuming C3 plants, C3 fed terrestrial animals, and some freshwater resources. Current investigation demonstrated social differences between elites and country people and is promising in paleodietary and daily life reconstruction. Acknowledgement I thank prof. dr. G. Grupe, Director of the Anthropological and Palaeoanatomical State Collection in Munich for providing the opportunity to work in her laboratory. The part of this work was funded by DAAD. Antanaitis-Jacobs, Indre, et al. "Diet in early Lithuanian prehistory and the new stable isotope evidence." Archaeologia Baltica 12 (2009): 12-30. Le Huray, Jonathan D., and Holger

  7. Quantifying MTBE biodegradation in the Vandenberg Air Force Base ethanol release study using stable carbon isotopes

    Science.gov (United States)

    McKelvie, Jennifer R.; Mackay, Douglas M.; de Sieyes, Nicholas R.; Lacrampe-Couloume, Georges; Sherwood Lollar, Barbara

    2007-12-01

    Compound-specific isotope analysis (CSIA) was used to assess biodegradation of MTBE and TBA during an ethanol release study at Vandenberg Air Force Base. Two continuous side-by-side field releases were conducted within a preexisting MTBE plume to form two lanes. The first involved the continuous injection of site groundwater amended with benzene, toluene and o-xylene ("No ethanol lane"), while the other involved the continuous injection of site groundwater amended with benzene, toluene and o-xylene and ethanol ("With ethanol lane"). The δ 13C of MTBE for all wells in the "No ethanol lane" remained constant during the experiment with a mean value of - 31.3 ± 0.5‰ ( n = 40), suggesting the absence of any substantial MTBE biodegradation in this lane. In contrast, substantial enrichment in 13C of MTBE by 40.6‰, was measured in the "With ethanol lane", consistent with the effects of biodegradation. A substantial amount of TBA (up to 1200 μg/L) was produced by the biodegradation of MTBE in the "With ethanol lane". The mean value of δ 13C for TBA in groundwater samples in the "With ethanol lane" was - 26.0 ± 1.0‰ ( n = 32). Uniform δ 13C TBA values through space and time in this lane suggest that substantial anaerobic biodegradation of TBA did not occur during the experiment. Using the reported range in isotopic enrichment factors for MTBE of - 9.2‰ to - 15.6‰, and values of δ 13C of MTBE in groundwater samples, MTBE first-order biodegradation rates in the "With ethanol lane" were 12.0 to 20.3 year - 1 ( n = 18). The isotope-derived rate constants are in good agreement with the previously published rate constant of 16.8 year - 1 calculated using contaminant mass-discharge for the "With ethanol lane".

  8. Stable isotope genealogy of meteorites

    International Nuclear Information System (INIS)

    Pillinger, C.T.

    1988-01-01

    One of the oldest problems in meteoritics is that of taxonomically grouping samples. In recent years the use of isotopes, particularly oxygen isotopes has proved very successful in this respect. Other light-element systematics potentially can perform the same function. For example, nitrogen in iron meteorites, and nitrogen and carbon in ureilites and SNC meteorites. These measurements will serve to extend and augment existing classification schemes and provide clues to the nature of meteorite parent bodies. They can also aid in the recognition of the isotopic signatures relating to inaccessible regions of the Earth. (author)

  9. Stable isotope composition of bulk and secondary carbonates from the Quaternary loess-paleosol sequence in Sutto, Hungary

    DEFF Research Database (Denmark)

    Koeniger, Paul; Barta, Gabriella; Thiel, Christine

    2014-01-01

    reveal pedogenetic information during the different climatic phases. Carbon and oxygen isotope analyses are valuable to classify secondary carbonates and to serve as proxies for the interpretation of paleoenvironmental conditions, e.g. moisture conditions, leaching, the role of organic matter...

  10. Differential utilization of allochthonous and autochthonous carbon by aquatic insects of two shrub-steppe desert spring-streams: A stable carbon isotope analysis and critique of the method

    Energy Technology Data Exchange (ETDEWEB)

    Mize, A. L. [Old Dominion Univ., Norfolk, VA (United States)

    1993-06-01

    The purpose of this study is to assess whether the carbon supporting stream food webs comes principally from terrestrial sources or is produced within the stream. Lacking data to resolve the allochthonous/autochthonous issue with any finality, stream ecologists have alternately postulated that stream carbon was principally autochthonous or principally allochthonous. Others argued that autochthonous and allochthonous carbon resources cannot be separated and that the allochthonous/autochthonous dependence issue is unresolvable. Many investigators have seized upon stable carbon isotopes technology as the tool to resolve the controversy. Unfortunately most investigators have conceded that the results are rarely quantitative and that the qualitative relationships are ambiguous. This study points out the fallacies of trying to conjure single isotopic values for either allochthonous or autochthonous carbon. It suggests that stable carbon isotope technology is not reliable in establishing specific consumer/food source relations and that it is not suitable for assessing allochthonous/autochthonous carbon dependence in freshwater streams.

  11. Stable Isotope Group 1984 progress report

    International Nuclear Information System (INIS)

    Lyon, G.L.

    1985-04-01

    The work of the group in 1984 is described and includes studies in isotope geology, isotope hydrology, geochronology, isotope biology and mass spectrometer instrumentation. Geothermal studies have decreased compared to other years, but major data summaries were made for Wairakei and Ngawha. The hydrology of Whakarewarewa and Rotorua is being elucidated using water isotopes. Models of the subsurface flows at Kawerau and Ngawha are being made to relate fluid to mineral isotope compositions. A study of the δ 13 C and δ 34 S compositions of New Zealand oils has been started. Groups of oils of related origin are being defined, and compositions will be compared with those of potential source rocks. A method was developed for isotope analysis of sulphur in rocks. The isotopic composition of water is being used to identify and characterise groundwater aquifers in the Wairarapa and at Poverty Bay. Stable carbon isotopes have been used to identify food sources for invertebrates, and to show biochemical pathways in lactation by cows. The geochronology group is involved in major studies in Antarctica, using U-Pb, Rb-Sr and K-Ar methods. Rocks from North Victoria Land, Marie Byrd Land and the USARP mountains are being compared with possible correlatives in New Zealand and Argentina. Strontium isotope data is being applied to the origin of magmas in several regions of New Zealand. The K-Ar data is being stored on computer files. Fission track measurements are being applied to unravel uplift histories in Westland and Taranaki

  12. Strontium stable isotope behaviour accompanying basalt weathering

    Science.gov (United States)

    Burton, K. W.; Parkinson, I. J.; Gíslason, S. G. R.

    2016-12-01

    The strontium (Sr) stable isotope composition of rivers is strongly controlled by the balance of carbonate to silicate weathering (Krabbenhöft et al. 2010; Pearce et al. 2015). However, rivers draining silicate catchments possess distinctly heavier Sr stable isotope values than their bedrock compositions, pointing to significant fractionation during weathering. Some have argued for preferential release of heavy Sr from primary phases during chemical weathering, others for the formation of secondary weathering minerals that incorporate light isotopes. This study presents high-precision double-spike Sr stable isotope data for soils, rivers, ground waters and estuarine waters from Iceland, reflecting both natural weathering and societal impacts on those environments. The bedrock in Iceland is dominantly basaltic, d88/86Sr ≈ +0.27, extending to lighter values for rhyolites. Geothermal waters range from basaltic Sr stable compositions to those akin to seawater. Soil pore waters reflect a balance of input from primary mineral weathering, precipitation and litter recycling and removal into secondary phases and vegetation. Rivers and ground waters possess a wide range of d88/86Sr compositions from +0.101 to +0.858. Elemental and isotope data indicate that this fractionation primarily results from the formation or dissolution of secondary zeolite (d88/86Sr ≈ +0.10), but also carbonate (d88/86Sr ≈ +0.22) and sometimes anhydrite (d88/86Sr ≈ -0.73), driving the residual waters to heavier or lighter values, respectively. Estuarine waters largely reflect mixing with seawater, but are also be affected by adsorption onto particulates, again driving water to heavy values. Overall, these data indicate that the stability and nature of secondary weathering phases, exerts a strong control on the Sr stable isotope composition of silicate rivers. [1] Krabbenhöft et al. (2010) Geochim. Cosmochim. Acta 74, 4097-4109. [2] Pearce et al. (2015) Geochim. Cosmochim. Acta 157, 125-146.

  13. Development of an enantiomer-specific stable carbon isotope analysis (ESIA) method for assessing the fate of α-hexachlorocyclo-hexane in the environment.

    Science.gov (United States)

    Badea, Silviu-Laurentiu; Vogt, Carsten; Gehre, Matthias; Fischer, Anko; Danet, Andrei-Florin; Richnow, Hans-Hermann

    2011-05-30

    α-Hexachlorocyclohexane (α-HCH) is the only chiral isomer of the eight 1,2,3,4,5,6-HCHs and we have developed an enantiomer-specific stable carbon isotope analysis (ESIA) method for the evaluation of its fate in the environment. The carbon isotope ratios of the α-HCH enantiomers were determined for a commercially available α-HCH sample using a gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) system equipped with a chiral column. The GC-C-IRMS measurements revealed δ-values of -32.5 ± 0.8‰ and -32.3 ± 0.5‰ for (-) α-HCH and (+) α-HCH, respectively. The isotope ratio of bulk α-HCH was estimated to be -32.4 ± 0.6‰ which was in accordance with the δ-values obtained by GC-C-IRMS (-32.7 ± 0.2‰) and elemental analyzer-isotope ratio mass spectrometry (EA-IRMS) of the bulk α-HCH (-32.1 ± 0.1‰). The similarity of the isotope ratio measurements of bulk α-HCH by EA-IRMS and GC-C-IRMS indicates the accuracy of the chiral GC-C-IRMS method. The linearity of the α-HCH ESIA method shows that carbon isotope ratios can be obtained for a signal size above 100 mV. The ESIA measurements exhibited standard deviations (2σ) that were mostly IRMS method, the isotope compositions of individual enantiomers in biodegradation experiments of α-HCH with Clostridium pasteurianum and samples from a contaminated field site were determined. The isotopic compositions of the α-HCH enantiomers show a range of enantiomeric and isotope patterns, suggesting that enantiomeric and isotope fractionation can serve as an indicator for biodegradation and source characterization of α-HCH in the environment. Copyright © 2011 John Wiley & Sons, Ltd.

  14. Stable isotope research pool inventory

    International Nuclear Information System (INIS)

    1986-08-01

    This report contains a listing of electromagnetically separated stable isotopes which are available at the Oak Ridge National Laboratory for distribution for nondestructive research use on a loan basis. This inventory includes all samples of stable isotopes in the Research Materials Collection and does not designate whether a sample is out on loan or is in reprocessing. For some of the high-abundance, naturally occurring isotopes, larger amounts can be made available; for example, Ca-40 and Fe-56. All requests for the loan of samples should be submitted with a summary of the purpose of the loan to: Iotope Distribution Office, Oak Ridge National Laboratory, P.O. Box X, Oak Ridge, Tennessee 37831. Requests from non-DOE contractors and from foreign institutions require DOE approval

  15. Stable isotopes and the environment

    International Nuclear Information System (INIS)

    Krouse, H.R.

    1990-01-01

    Whereas traditionally, stable isotope research has been directed towards resource exploration and development, it is finding more frequent applications in helping to assess the impacts of resource utilization upon ecosystems. Among the many pursuits, two themes are evident: tracing the transport and conversions of pollutants in the environment and better understanding of the interplay among environmental receptors, e.g. food web studies. Stable isotope data are used primarily to identify the presence of pollutants in the environment and with a few exceptions, the consequence of their presence must be assessed by other techniques. Increasing attention has been given to the isotopic composition of humans with many potential applications in areas such as paleodiets, medicine, and criminology. In this brief overview examples are used from the Pacific Rim to illustrate the above concepts. 26 refs., 1 tab., 3 figs

  16. Estimation of food composition of Hodotermes mossambicus (Isoptera: Hodotermitidae) based on observations and stable carbon isotope ratios

    CSIR Research Space (South Africa)

    Symes, CT

    2011-04-01

    Full Text Available , observations (93.8%) and stable isotopes (92.6%), no significant differ- ence was recognized (t-test dependent samples, t = 0.84, P = 0.46). Discussion Observations A widely used method of studying feeding habits in termites is by assessing the choice.... Canadian Journal of Zoology, 78, 1?27. LaFage, J.P. and Nutting, W.L. (1978) Food and feeding habits of termites. Nutrient Dynamics of Termites (ed. M.V. Brian), pp. 165?232. Cambridge University Press, Cambridge. McKechnie, A.E. (2004) Stable isotopes...

  17. Isotopes Will Let the Cat Out of the Bag: A Carbon and Nitrogen Stable Isotopic Analysis of Dry Cat Food Brands

    Science.gov (United States)

    Zelanko, P. M.

    2011-12-01

    There are a plethora of healthy cat food brands that make a wide variety of claims about the nutrition of their product and the lack of nutrition of their competitors. The claims range from "No sugar or corn" to "Real meat is always the 1st ingredient". The two major disagreements in the cat food market are the nutritional value of corn and the realness of meat products. Here I present a carbon and nitrogen stable isotopic analysis of a wide range of dry cat food brands. The beginning assumption was brands with claims of no corn would be depleted in δ13C compared to brands with corn and brands with real meat as the 1st ingredient would be enriched in δ 15N compared to brands with meat as a lesser ingredient. Preliminary results show brands with no corn (δ13C ~ -22%) are depleted compared to brands with corn (δ13C ~ -17%), which is to be expected. However, brands that claim real meat is the 1st ingredient are slightly depleted (δ15N ~ 3.5%) compared to brands with proportionally less meat (δ15N ~ 5%); the opposite of what was anticipated. Also, the stable isotopes of three house cats, that were all fed the same dry diet (corn as major ingredient), were tracked over time as they were switched to a diet with no corn. Variation was present in the first round of analysis and persisted throughout the dietary change, suggesting individual cats may absorb nutrients from the identical diets differently.

  18. Complementary stable carbon isotope ratio and amount of substance measurements in sports anti-doping.

    Science.gov (United States)

    Cawley, Adam T; George, Adrian V

    2012-12-01

    The detection of steroids originating from synthetic precursors against a background of their chemically identical natural analogues has proven to be a significant challenge for doping control laboratories accredited by the World Anti-Doping Agency (WADA). The complementary application of gas chromatography-mass spectrometry (GC-MS) and gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) has been demonstrated to provide specific detection of endogenous steroid misuse for improved anti-doping analysis. Markers of synthetically derived steroids are reviewed on the basis of abnormal urinary excretions and low (13)C content. A combinatorial approach is presented for the interpretation of GC-MS and GC-C-IRMS data in the anti-doping context. This methodology can allow all relevant information concerning an individual's metabolism to be assessed in order to make an informed decision with respect to a doping violation. Copyright © 2012 John Wiley & Sons, Ltd.

  19. Testing of an automated online EA-IRMS method for fast and simultaneous carbon content and stable isotope measurement of aerosol samples

    Science.gov (United States)

    Major, István; Gyökös, Brigitta; Túri, Marianna; Futó, István; Filep, Ágnes; Hoffer, András; Molnár, Mihály

    2016-04-01

    Comprehensive atmospheric studies have demonstrated that carbonaceous aerosol is one of the main components of atmospheric particulate matter over Europe. Various methods, considering optical or thermal properties, have been developed for quantification of the accurate amount of both organic and elemental carbon constituents of atmospheric aerosol. The aim of our work was to develop an alternative fast and easy method for determination of the total carbon content of individual aerosol samples collected on prebaked quartz filters whereby the mass and surface concentration becomes simply computable. We applied the conventional "elemental analyzer (EA) coupled online with an isotope ratio mass spectrometer (IRMS)" technique which is ubiquitously used in mass spectrometry. Using this technique we are able to measure simultaneously the carbon stable isotope ratio of the samples, as well. During the developing process, we compared the EA-IRMS technique with an off-line catalytic combustion method worked out previously at Hertelendi Laboratory of Environmental Studies (HEKAL). We tested the combined online total carbon content and stable isotope ratio measurement both on standard materials and real aerosol samples. Regarding the test results the novel method assures, on the one hand, at least 95% of carbon recovery yield in a broad total carbon mass range (between 100 and 3000 ug) and, on the other hand, a good reproducibility of stable isotope measurements with an uncertainty of ± 0.2 per mill. Comparing the total carbon results obtained by the EA-IRMS and the off-line catalytic combustion method we found a very good correlation (R2=0.94) that proves the applicability of both preparation method. Advantages of the novel method are the fast and simplified sample preparation steps and the fully automated, simultaneous carbon stable isotope ratio measurement processes. Furthermore stable isotope ratio results can effectively be applied in the source apportionment

  20. Compound-specific stable carbon isotopic composition of petroleum hydrocarbons as a tool for tracing the source of oil spills

    International Nuclear Information System (INIS)

    Li Yun; Xiong Yongqiang; Yang Wanying; Xie Yueliang; Li Siyuan; Sun Yongge

    2009-01-01

    With the increasing demand for and consumption of crude oils, oil spill accidents happen frequently during the transportation of crude oils and oil products, and the environmental hazard they pose has become increasingly serious in China. The exact identification of the source of spilled oil can act as forensic evidence in the investigation and handling of oil spill accidents. In this study, a weathering simulation experiment demonstrates that the mass loss of crude oils caused by short-term weathering mainly occurs within the first 24 h after a spill, and is dominated by the depletion of low-molecular weight hydrocarbons ( 18 n-alkanes). Short-term weathering has no significant effect on δ 13 C values of individual n-alkanes (C 12 -C 33 ), suggesting that a stable carbon isotope profile of n-alkanes can be a useful tool for tracing the source of an oil spill, particularly for weathered oils or those with a relatively low concentration or absence of sterane and terpane biomarkers

  1. Stable carbon isotopic assessment of prehistoric diets in the south-western Cape, Cape Town, South Africa

    Energy Technology Data Exchange (ETDEWEB)

    Sealy, J C

    1984-01-01

    This thesis consists of a stable carbon isotopic assessment of the diets of the Holocene human inhabitants of the south-western Cape, South-Africa. Samples of the foods these people ate were collected from each of the four major physiographic zones in the area, and their /sup 13/C//sup 12/C ratios measured. A total of more than 200 such analyses enabled the estimation of the average delta /sup 13/C values of prehistoric human diets in each zone. This information is used to interpret delta /sup 13/C measurements on a series of archaeological human skeletons. The results are consistent with a model of prehistoric subsistence behaviour in which people living at the coast made intensive use of marine food resources throughout the Holocene, consuming such a large proportion of these foods that they must have spent much, if not all of their time at the coast. Inland skeletons reflect an almost entirely terrestrial diet. These results contradict hypotheses about seasonal population movements between the coast and the interior generated from excavated archaeological material. Considerable changes in many of our current views of the Late Stone Age of the south-western Cape will have to be made in order to accommodate these data.

  2. Determination of gas recovery efficiency at two Danish landfills by performing downwind methane measurements and stable carbon isotopic analysis

    DEFF Research Database (Denmark)

    Fathi Aghdam, Ehsan; Fredenslund, Anders Michael; Chanton, Jeffrey

    2018-01-01

    In this study, the total methane (CH4) generation rate and gas recovery efficiency at two Danish landfills were determined by field measurements. The landfills are located close to each other and are connected to the same gas collection system. The tracer gas dispersion method was used...... for quantification of CH4 emissions from the landfills, while the CH4 oxidation efficiency in the landfill cover layers was determined by stable carbon isotopic technique. The total CH4 generation rate was estimated by a first-order decay model (Afvalzorg) and was compared with the total CH4 generation rate...... determined by field measurements. CH4 emissions from the two landfills combined ranged from 29.1 to 49.6 kg CH4/h. The CH4 oxidation efficiency was 6–37%, with an average of 18% corresponding to an average CH4 oxidation rate of 8.1 kg CH4/h. The calculated gas recovery efficiency was 59–76%, indicating...

  3. Stable carbon isotope ratios and intrinsic water-use efficiency of Miocene fossil leaves compared to modern congeners

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, J.D.; Zhang, J.; Rember, W.C.; Jennings, D.; Larson, P. (Univ. of Idaho, Moscow, ID (United States))

    1994-06-01

    Miocene fossil leaves of forest trees were extracted from the Clarkia, Idaho fossil beds and their stable carbon isotope ratios were analyzed. Fossils had higher lignin concentrations and lower cellulose concentrations that modern leaves due to diagenesis and the HF used to extract the fossils. Therefore, [delta][sup 13]C of extracted fossil lignin was compared to that of modern lignin. Fossil lignin [delta][sup 13]C was significantly different from that of congeneric modern leaves (paired t-test, P<0.0001), but was 1.9% less negative. Gymnosperms (Metasequoia, Taxodium) were less negative than angiosperms (e.g., Magnolia, Quercus, Acer, Persea), but no difference between evergreen and deciduous species was detected. Using published estimates of the concentration and [delta][sup 13]C of atmospheric CO[sub 2] during the Miocene was estimated the CO[sub 2] partial pressure gradient across the stomata (intrinsic water-use efficiency). Intrinsic water-use efficiency was at least 70% higher during this past [open quotes]greenhouse[close quotes] period than at present.

  4. Stable isotopic carbon composition of apples and their subfractions--juice, seeds, sugars, and nonvolatile acids.

    Science.gov (United States)

    Lee, H S; Wrolstad, R E

    1988-01-01

    The 13C:12C ratios of 8 authentic apple juice samples and their subfractions were determined by mass spectrometry. Apples from Argentina, Mexico, New Zealand, and the United States were processed into juice; pulp was collected from the milled fruit and seeds were collected from the press-cake. Sugars, nonvolatile acids, and phenolics were isolated from the juice by treatment with ion-exchange resins and polyvinylpyrrolidone (PVPP). The mean value for all juice samples was -24.2% which is close to the values reported by other investigators. Juice from apples grown in Argentina, Mexico, and New Zealand did not differ from U.S. samples. The isotopic composition of the subfractions ranged from -22.0 to -31.0%. The values for the pulp were essentially the same as for juice. The sugar fraction was slightly less negative than the juice; the nonvolatile acid and phenolic fractions were more negative. The levels of nonvolatile acids and phenolics in apple juice are low, however, so these compounds contribute little to overall delta 13C values in juice.

  5. Stable carbon isotopes to monitor the CO2 source mix in the urban environment

    Science.gov (United States)

    Vogel, F. R.; Wu, L.; Ramonet, M.; Broquet, G.; Worthy, D. E. J.

    2014-12-01

    Urban areas are said to be responsible for approximately 71% of fossil fuel CO2 emissions while comprising only two percent of the land area [IEA, 2008]. This limited spatial expansion could facility a monitoring of anthropogenic GHGs from atmospheric observations. As major sources of emissions, cities also have a huge potential to drive emissions reductions. To effectively manage emissions, cities must however, first establish techniques to validate their reported emission statistics. A pilot study which includes continues 13CO2 data from calibrated cavity ring-down spectrometers [Vogel et al. 2013] of two "sister sites" in the vicinity of Toronto, Canada is contrasted to recent observations of 13CO2 observations in Paris during significant pollution events. Using Miller-Tans plots [Miller and Tans, 2003] for our multi-season observations reveals significant changes of the source signatures of night time CO2 emissions which reflect the importance of natural gas burning in Megacities (up to 80% of fossil fuel sources) and show-case the potential of future isotope studies to determine source sectors. Especially the winter data this approach seems suitable to determine the source contribution of different fuel types (natural gas, liquid fuels and coal) which can inform the interpretation of other Greenhouse Gases and air pollution levels.

  6. Branched GDGTs in Lacustrine Environments: Tracing Allochthonous and Autochthonous Sources Using Compound-Specific Stable Carbon Isotope Analysis

    Science.gov (United States)

    Weber, Y.; S Sinninghe Damsté, J.; Lehmann, M. F.; Niemann, H.; Schubert, C. J.

    2015-12-01

    Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are bacterial membrane lipids that are ubiquitous in soils and peat, as well as in sediments of lakes, rivers and coastal marine environments. It has been found that the distribution of brGDGTs changes systematically with ambient temperature and pH, attesting to their potential as proxy indicators for paleoclimatic reconstruction. In lacustrine sedimentary archives, brGDGTs can originate from two sources: (1) allochthonous soil organic matter and (2) autochthonous brGDGTs produced within the lake system, both of which display fairly distinct temperature-brGDGT relationships. Until now, disentangling the relative contribution of these sources was impossible, complicating the use of brGDGTs for quantitative paleotemperature reconstructions. BrGDGTs in soils display a narrow range with respect to their stable carbon isotope composition (δ13C), generally between -27 and -30 ‰, whereas we recently found contrasting δ13C values as low as -43 ‰ to -46 ‰ for brGDGTs in sediments of a small Alpine lake. To trace the origin of this distinct isotope signal, we determined the 13C content of brGDGTs in suspended particulate matter (SPM) from the water column of Lake Lugano (Switzerland). The δ13C of SPM-derived brGDGTs decreased systematically from -34 ‰ in the mixolimnion to -41 ‰ in the anoxic monimolimnion of Lake Lugano, providing evidence for aquatic in situ production of 13C-depleted brGDGT. In order to study whether the negative δ13C offset of water column- vs. soil-derived brGDGTs may serve as an indicator for lacustrine brGDGT production, we also analyzed surface sediments from 36 lakes across the Alpine Region. In most (~85 %) of the studied lake sediments, the δ13C of brGDGTs ranged between -34 ‰ and -45 ‰, indicating predominance or a substantial contribution of aquatically produced brGDGTs. However, in some lakes (~15 %) δ13C values between -27 ‰ and -30 ‰ suggest a mainly

  7. The production of stable isotopes in Spain

    Energy Technology Data Exchange (ETDEWEB)

    Urgel, M; Iglesias, J; Casas, J; Saviron, J M; Quintanilla, M

    1965-07-01

    The activities developed in the field of the production of stable isotopes by means of ion-exchange chromatography and thermal diffusion techniques are reported. The first method was used to study the separation of the nitrogen and boron isotopes, whereby the separation factor was determined by the break through method. Values ranging from 1,028 to 1,022 were obtained for the separation factor of nitrogen by using ammonium hydroxide solutions while the corresponding values as obtained for boron amounted to 1,035-1,027 using boric acid solutions. Using ammonium chloride or acetate and sodium borate, respectively, resulted in the obtention of values for the separation factor approaching unity. The isotopic separation has been carried out according to the method of development by displacement. The separation of the isotopes of the noble gases, oxygen, nitrogen and carbon has been accomplished resorting to the method of thermal diffusion. (Author) 16 refs.

  8. Fractional Absorption of Active Absorbable Algal Calcium (AAACa and Calcium Carbonate Measured by a Dual Stable-Isotope Method

    Directory of Open Access Journals (Sweden)

    Steven A. Abrams

    2010-07-01

    Full Text Available With the use of stable isotopes, this study aimed to compare the bioavailability of active absorbable algal calcium (AAACa, obtained from oyster shell powder heated to a high temperature, with an additional heated seaweed component (Heated Algal Ingredient, HAI, with that of calcium carbonate. In 10 postmenopausal women volunteers aged 59 to 77 years (mean ± S.D., 67 ± 5.3, the fractional calcium absorption of AAACa and CaCO3 was measured by a dual stable isotope method. 44Ca-enriched CaCO3 and AAACa were administered in all subjects one month apart. After a fixed-menu breakfast and pre-test urine collection (Urine 0, 42Ca-enriched CaCl2 was intravenously injected, followed by oral administration of 44Ca-enriched CaCO3 without carrier 15 minutes later, and complete urine collection for the next 24 hours (Urine 24. The fractional calcium absorption was calculated as the ratio of Augmentation of 44Ca from Urine 0 to Urine 24/ augmentation of 42Ca from Urine 0 to Urine 24. Differences and changes of 44Ca and 42Ca were corrected by comparing each with 43Ca. Fractional absorption of AAACa (mean ± S.D., 23.1 ± 6.4, was distinctly and significantly higher than that of CaCO3 (14.7 ± 6.4; p = 0.0060 by paired t-test. The mean fractional absorption was approximately 1.57-times higher for AAACa than for CaCO3. The serum 25(OH vitamin D level was low (mean ± S.D., 14.2 ± 4.95 ng/ml, as is common in this age group in Japan. Among the parameters of the bone and mineral metabolism measured, none displayed a significant correlation with the fractional absorption of CaCO3 and AAACa. Higher fractional absorption of AAACa compared with CaCO3 supports previous reports on the more beneficial effect of AAACa than CaCO3 for osteoporosis.

  9. Carbon and nitrogen stable isotope ratios of pelagic zooplankton elucidate ecohydrographic features in the oligotrophic Red Sea

    KAUST Repository

    Kürten, Benjamin

    2015-11-10

    Although zooplankton occupy key roles in aquatic biogeochemical cycles, little is known about the pelagic food web and trophodynamics of zooplankton in the Red Sea. Natural abundance stable isotope analysis (SIA) of carbon (δ13C) and N (δ15N) is one approach to elucidating pelagic food web structures and diet assimilation Integrating the combined effects of ecological processes and hydrography, ecohydrographic features often translate into geographic patterns in δ13C and δ15N values at the base of food webs. This is due, for example, to divergent 15N abundances in source end-members (deep water sources: high δ15N, diazotrophs: low δ15N). Such patterns in the spatial distributions of stable isotope values were coined isoscapes. Empirical data of atmospheric, oceanographic, and biological processes, which drive the ecohydrographic gradients of the oligotrophic Red Sea, are under-explored and some rather anticipated than proven. Specifically, five processes underpin Red Sea gradients: a) monsoon-related intrusions of nutrient-rich Indian Ocean water; b) basin scale thermohaline circulation; c) mesoscale eddy activity that causes up-welling of deep water nutrients into the upper layer; d) the biological fixation of atmospheric nitrogen (N2) by diazotrophs; and e) the deposition of aerosol-derived N. This study assessed relationships between environmental samples (nutrients, chlorophyll a), oceanographic data (temperature, salinity, current velocity [ADCP]), particulate organic matter (POM), and net-phytoplankton, with the δ13C and δ15N values of zooplankton collected in spring 2012 from 16°28’ to 26°57’N along the central axis of the Red Sea. The δ15N of bulk POM and most zooplankton taxa increased from North (Duba) to South (Farasan). The potential contribution of deep water nutrient-fueled phytoplankton, POM, and diazotrophs varied among sites. Estimates suggested higher diazotroph contributions in the North, a greater contribution of POM in the South

  10. Use of stable isotopes in agriculture

    International Nuclear Information System (INIS)

    Ali, F. K.

    2011-01-01

    Scientific research is considered to be one of the most important steps to achieve sustainable agriculture development. This paper is focused on the role of stable isotopes and their applications in agriculture for plant and animal production, and to study the relationship between soil, plant, air, water, nutrients and agricultural pests. Symbiotic N 2 fixation and efficient use of chemical and organic N fertilizers using 15 N were reported. Factors affecting 13 C values and application of carbon isotope discrimination to physiological and eco-physiological studies and selection of genotypes with improved water-use efficiency and drought tolerance and the recent progress in this field are reviewed. Moreover, the use of carbon isotope compositions in monitoring environmental changes and its various applications in food technology, animal production and entomology are discussed. (author)

  11. Utilization of carbon 13-labelled stable isotopes for studying drug toxicity on cellular metabolism

    International Nuclear Information System (INIS)

    Herve, M.; Wietzerbin, J.; Tran-Dinh, S.

    1994-01-01

    A new approach for studying the effects of two drugs, amphotericine B (AMB), an anti-fungal antibiotic, and 2-deoxy-D-glucose (DG), on the glucose metabolism in brewer yeast cells (Saccharomyces cerevisiae), is presented; AMB interacts with the membrane sterols, inducing formation of pores through which ions and small molecules can pass. DG may enter in the cytosol, where it is phosphoryled by hexokinase into deoxy-D-glucose 6-phosphate (DG6P) which disappears very slowly. DG slows down the glycolysis process and induces the formation of new substances. This paper shows the advantages of utilizing carbon 13-labelled substrates combined to the NMR-13C and NMR-1H techniques. 6 figs., 5 refs

  12. Stable isotope measurements of atmospheric CO2

    International Nuclear Information System (INIS)

    White, J.W.C.; Ferretti, D.F.; Vaughn, B.H.; Francey, R.J.; Allison, C.E.

    2002-01-01

    The measurement of stable carbon isotope ratios of atmospheric carbon dioxide, δ 13 CO 2 are useful for partitioning surface-atmospheric fluxes into terrestrial and oceanic components. δC 18 OO also has potential for segregating photosynthetic and respiratory fluxes in terrestrial ecosystems. Here we describe in detail the techniques for making these measurements. The primary challenge for all of the techniques used to measure isotopes of atmospheric CO 2 is to achieve acceptable accuracy and precision and to maintain them over the decades needed to observe carbon cycle variability. The keys to success such an approach are diligent intercalibrations of laboratories from around the world, as well as the use of multiple techniques such as dual inlet and GC-IRMS and the intercomparison of such measurements. We focus here on two laboratories, the Stable Isotope Lab at the Institute for Arctic and Alpine Research (INSTAAR) at the University of Colorado is described and the Commonwealth Scientific and Industrial Research Organisation - Atmospheric Research (CSIRO). Different approaches exist at other laboratories (e.g. programs operated by Scripps Institution of Oceanography (SIO) and The Center for Atmospheric and Oceanic Studies, Toboku University (TU)) however these are not discussed here. Finally, we also discuss the recently developed Gas Chromatography - Isotope Ratio Mass Spectrometry (GC-IRMS) technique which holds significant promise for measuring ultra-small samples of gas with good precision. (author)

  13. Carbon-14, tritium, stable isotope and chemical measurements on thermal waters from the Tauranga region

    International Nuclear Information System (INIS)

    Stewart, M.K.; McGill, R.C.; Taylor, C.B.; Whitehead, N.E.; Downes, C.J.

    1984-03-01

    The chemical compositions of groundwater from the Tauranga region are affected to varying degrees by reducing conditions due to buried organic matter. The levels of some dissolved constituents are also affected by mixing with sea water contained within the rocks and by rock-water interaction. Dissolved gas compositions range from oxygen-bearing to methane-bearing reflecting the varying redox conditions. Excess air may be present but further experiments are necessary to confirm this. Apparent ages deduced from carbon-14 measurements (corrected using 12C dilution and 13C fractionation methods) range from 2-25,000 years, suggesting that some of the waters were recharged during late Pleistocene or early Holocene time. ΔD and Δ18 O values of the oldest waters are slightly more negative than those of younger samples; this may indicate recharge during a cooler climate, in agreement with the 14C ages. Very low but significantly non-zero tritium contents (TR=(0.007-0.059)+-0.007) were measured using the high tritium-enrichment facilities at INS and the very low-background counters at the University of Bern. The tritium is thought to derive from contamination or nuclear reactions in the aquifer rocks rather than from recharge water

  14. Trophic position of coexisting krill species: a stable isotope approach

    DEFF Research Database (Denmark)

    Agersted, Mette Dalgaard; Bode, Antonio; Nielsen, Torkel Gissel

    2014-01-01

    Four krill species with overlapping functional biology coexist in Greenland waters. Here, we used stable isotopes to investigate and discuss their trophic role and mode of coexistence. Bulk carbon (δ13C) and nitrogen (δ15N) stable isotope analyses of Thysanoessa longicaudata, T. inermis, T. raschii...

  15. Indoor and outdoor urban atmospheric CO2: Stable carbon isotope constraints on mixing and mass balance

    International Nuclear Information System (INIS)

    Yanes, Yurena; Yapp, Crayton J.

    2010-01-01

    Research highlights: → 13 C of indoor CO 2 indicates proportion of C 4 -derived carbon in occupants' diet. → Flux balance model for ventilated rooms shows rapid approach to CO 2 steady-state. → From extant indoor CO 2 data more dietary C 4 carbon in American than European diets. → Local outdoor urban CO 2 increase of 17 ppm in ten years, no change in average 13 C. - Abstract: From July to November 2009, concentrations of CO 2 in 78 samples of ambient air collected in 18 different interior spaces on a university campus in Dallas, Texas (USA) ranged from 386 to 1980 ppm. Corresponding δ 13 C values varied from -8.9 per mille to -19.4 per mille. The CO 2 from 22 samples of outdoor air (also collected on campus) had a more limited range of concentrations from 385 to 447 ppm (avg. = 408 ppm), while δ 13 C values varied from -10.1 per mille to -8.4 per mille (avg.=-9.0 per mille). In contrast to ambient indoor and outdoor air, the concentrations of CO 2 exhaled by 38 different individuals ranged from 38,300 to 76,200 ppm (avg. = 55,100 ppm), while δ 13 C values ranged from -24.8 per mille to -17.7 per mille (avg. = -21.8 per mille). The residence times of the total air in the interior spaces of this study appear to have been on the order of 10 min with relatively rapid approaches (∼30 min) to steady-state concentrations of ambient CO 2 gas. Collectively, the δ 13 C values of the indoor CO 2 samples were linearly correlated with the reciprocal of CO 2 concentration, exhibiting an intercept of -21.8 per mille, with r 2 = 0.99 and p 2 data representing 18 interior spaces (with varying numbers of occupants), and the coincidence of the intercept (-21.8 per mille) with the average δ 13 C value for human-exhaled CO 2 demonstrates simple mixing between two inputs: (1) outdoor CO 2 introduced to the interior spaces by ventilation systems, and (2) CO 2 exhaled by human occupants of those spaces. If such simple binary mixing is a common feature of interior spaces, it

  16. High Relative Abundance of Biofuel Sourced Ethanol in Precipitation in the US and Brazil Determined Using Compound Specific Stable Carbon Isotopes

    Science.gov (United States)

    Shimizu, M. S.; Felix, J. D. D.; Casas, M.; Avery, G. B., Jr.; Kieber, R. J.; Mead, R. N.; Willey, J. D.; Lane, C.

    2017-12-01

    Ethanol biofuel production and consumption have increased exponentially over the last two decades to help reduce greenhouse gas emissions. Currently, 85% of global ethanol production and consumption occurs in the US and Brazil. Increasing biofuel ethanol usage in these two countries enhances emissions of uncombusted ethanol to the atmosphere contributing to poor air quality. Although measurements of ethanol in the air and the precipitation reveal elevated ethanol concentrations in densely populated cities, other sources such as natural vegetation can contribute to emission to the atmosphere. Previous modeling studies indicated up to 12% of atmospheric ethanol is from anthropogenic emissions. Only one gas phase study in southern Florida attempted to constrain the two sources through direct isotopic measurements. The current study used a stable carbon isotope method to constrain sources of ethanol in rainwater from the US and Brazil. A method was developed using solid phase microextraction (SPME) with subsequent analysis by gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). Stable carbon isotope signatures (δ13C) of vehicle ethanol emission sources for both the US (-9.8‰) and Brazil (-12.7‰) represented C4 plants as feedstock (corn and sugarcane) for biofuel production. An isotope mixing model using biofuel from vehicles (C4 plants) and biogenic (C3 plants) end-members was implemented to estimate ethanol source apportionment in the rain. We found that stable carbon isotope ratio of ethanol in the rain ranged between -22.6‰ and -12.7‰. Our results suggest that the contribution of biofuel to atmospheric ethanol can be higher than previously estimated. As biofuel usage increasing globally, it is essential to determine the relative abundance of anthropogenic ethanol in other areas of the world.

  17. Use of Stable Carbon and Nitrogen Isotopes for Trophic Level Evaluation and Food Webs Reconstruction in the Bay of Biscay : Case Study

    Energy Technology Data Exchange (ETDEWEB)

    Chouvelon, T.; Caurant, F.; Mendez Fernandez, P.; Bustamante, P. [Littoral Environnement et Societes, La Rochelle (France); Spitz, J. [Centre de Recherche sur les Mammiferes Marins, La Rochelle (France)

    2013-07-15

    Assessing species' trophic level is one key aspect of ecosystem models, providing an indicator to monitor trophic links and ecosystem changes. The stable isotope ratios (SIR) of carbon and nitrogen provide longer term information on the average diet of consumers than the traditional stomach content method. However, using SIR in predators implies a good knowledge of the factors influencing prey species signature and lower trophic levels themselves, such as spatial and temporal variations. In this study, 129 species belonging to several taxa (i.e. crustaceans, molluscs, fish, marine mammals) from the Bay of Biscay where analysed for their isotopic signatures. Results confirmed the existence of several trophic food webs with probable different baseline signatures in this area, an essential consideration when using the isotopic tool for calculating species trophic level and potential evolution in space and time. Results demonstrated a spatial gradient from the shoreline to the oceanic domain for both carbon and nitrogen. (author)

  18. Molecular sieve isolation technique for use in stable carbon isotope analysis of individual long-chain n-alkanes in crude oil

    International Nuclear Information System (INIS)

    Yamada, Keita; Kon, Makoto; Naraoka, Hiroshi; Ishiwatari, Ryoshi; Uzaki, Minoru.

    1994-01-01

    An isolation procedure of microgram amounts of long-chain n-alkanes from crude oil using molecular sieve was examined for its applicability to stable carbon isotope analysis by gas chromatography/isotope ratio mass spectrometry (GC/IRMS). The procedure examined is as follows: molecular sieve (type 5A, 200 mg) in 1 ml of isooctane solvent are mixed with a saturated hydrocarbon fraction extracted from an appropriate amount (approx. 20 mg) of crude oil and stayed at room temperatures for more than 3 hours. Long-chain n-alkanes are isolated by extraction with n-hexane after dissolution of the resulting molecular sieve with 47% hydrofluoric acid solution. The recoveries were 90±6% for C 15 -C 34 n-alkanes when their total amounts applied do not exceed 1.4 mg. No effect of the isolation procedure on carbon isotope ratios of n-alkanes was observed. (author)

  19. Interannual variability in seagrass carbon and nitrogen stable isotopes from the Florida Keys National Marine Sanctuary, a preliminary study

    Science.gov (United States)

    Fourqurean, J. W.; Fourqurean, J. W.; Anderson, W. T.; Anderson, W. T.

    2001-12-01

    The shallow marine waters surrounding the southern tip of Florida provide an ideal environment for seagrasses, which are the most common benthic community in the region. Yet, these communities are susceptible to a variety of anthropogenic disturbances, especially changes in water quality caused by an increase the nutrient flux to the near shore environment. In order to better understand the carbon and nitrogen isotopic ratio in marine plants, an extensive times series analysis was constructed from quarterly sampling of Thalassia testudinum (the dominate species in the study area) from 1996 through 1998. Sites for study where selected from permanent stations within the Florida Keys National Marine Sanctuary (FKNMS), from both sides of the Florida Keys - two stations on the bay side and two stations on the reef side. These data will also help to constrain elements of the carbon and nitrogen cycles affecting this region. The data analyzed over the three year study period show unique cyclic trends associated with seasonal changes in primary productivity and potentially changes in the nitrogen and carbon pools. Additionally, the analysis of our time series indicates that isotope food web studies need to take into account spatial and temporal changes when evaluating trophic levels. The mean carbon and nitrogen isotope values of T. testudinum from all 4 stations vary respectively from -7.2 per mil to -10.41 and 1.1 per mil to 2.2 per mil (n = 48). However, certain stations displayed anonymously depleted nitrogen isotope values, values as low as -1.2 per mil. These values potentially indicated that biogeochmical processes like N fixation, ammonification and denitrification cause regional pattern in the isotopic composition of the source DIN. Both carbon and nitrogen isotopes displayed seasonal enrichment-depletion trends, with maximum enrichment occurring during the summer. The overall seasonal variation for carbon 13 from the different stations ranged from 1 per mil to

  20. Stable isotope compositions of organic carbon and contents of organic carbon and nitrogen of lacustrine sediments from sub-arid northern Tanzania

    International Nuclear Information System (INIS)

    Muzuka, A.N.N.

    2006-01-01

    The stable isotope compositions of organic carbon (OC), and contents of OC and nitrogen for four sediment cores recovered from lakes Makat (located in the Ngorongoro Crater), Ndutu and Masek (located in the Serengeti Plains) are used to document sources of organic matter (OM) and climatic changes in sub-arid northern Tanzania during the late Pleistocene-Holocene period. Accelerate mass spectrometer (AMS) 14 C ages on total OM for sediments collected from the Ngorongoro Crater Lake indicate that the sedimentation rate is approximately 17 cm/ka. The δ 13 C values from the 20 cm long core (short core) show a downcore increase, whereas that of 500 cm long core (long core), show two peaks enriched in 13 C and three peaks depleted in 13 C. A general downcore increase in the δ 13 C values for the short core suggests changes in the relative proportion of C 3 and C 4 fraction increasing downcore. Similarly, low and high peaks in the long core suggest changes in the relative proportion of C 3 and C 4 with low values having high proportion of C 3 type of material, probably indicating changes in precipitation and lake levels in the area. Deposition of OM depleted in 13 C took place during periods of high precipitation and high lake levels. Although high content of OC and nitrogen in some core sections are associated with elevated C/N ratio values, diagenetic alteration of isotope signature is unlikely to have caused OC and isotope enrichment in sections having high contents of OC and nitrogen. The OC isotope record from Lake Ndutu shows a general downcore decrease in δ 13 C values and contents of OC and nitrogen. (author)

  1. Sources of CO{sub 2} in the Gulf of Trieste (N. Adriatic). Stable Carbon Isotope Evidence

    Energy Technology Data Exchange (ETDEWEB)

    Ogrinc, N.; Zavadlav, S. [Department of Environmental Sciences, Jozef Stefan Institute, Ljubljana (Slovenia); Turk, D. [Department of Oceanography, Dalhousie University, Halifax, Nova Scotia (Canada); Lamont-Doherty Earth Observatory, Earth Institute at Columbia University, Palisades, NY (United States); Faganeli, J. [Marine Biological Station National Institute of Biology, Piran (Slovenia)

    2013-07-15

    In the present study the influence of freshwater intrusions on the net carbon dynamics in the Gulf of Trieste (northern Adriatic Sea) were investigated. Carbonate mineral weathering dominates the inorganic carbon geochemical flux of the N Adriatic rivers and thus the origin of dissolved inorganic carbon (DIC) in the gulf seawater. Based on {delta}{sup 13}C{sub DIC} values and isotopic mass balance it was estimated that rivers represents about 20% of DIC in spring, while the riverine contribution in autumn is less pronounced probably due to intensive water mixing. The results, therefore, suggest that river inputs play a significant role in the carbon cycling in the Gulf of Trieste due to mixing of higher DIC riverine water with lower seawater DIC. The observed higher summer {delta}{sup 13}C{sub DIC} values were due to more pronounced photosynthetic carbon fractionation. (author)

  2. Stable isotopes of carbon dioxide in the marine atmosphere along a hemispheric course from China to Antarctica

    Science.gov (United States)

    Chen, Qingqing; Zhu, Renbin; Xu, Hua

    2013-12-01

    During the 24th Chinese Antarctic Expedition, the air samples were collected at 10:00 and 22:00 (local time) along the track of ship “Xuelong” from Shanghai Harbor, China to Antarctica. Carbon dioxide (CO2) concentrations and its isotopic compositions were measured in these samples. Mean CO2 concentration at 22:00 (419.4 ± 27.1 ppmv) was higher than that at 10:00 (392.7 ± 20.0 ppmv), whereas δ13C-CO2 values at 22:00 (-8.58 ± 0.47‰) were lower than those at 10:00 (-8.23 ± 0.49‰), indicating that the 13C/12C ratio might be associated with the photosynthesis and respiration of terrestrial or marine organisms during the diurnal cycle. Overall the mean δ13C- and δ18O-CO2 were -8.39 ± 0.51‰ and 0.03 ± 1.39‰, respectively, from 30°N to 69°S, and the δ13C significantly negatively correlated with δ18O-CO2. A small but progressive increase in δ13C values with increasing latitudes southward was in good agreement with the expected trend. The enhanced CO2 concentrations occurred in the atmosphere close to Eurasia continent, Philippines, Malaysia and Indonesia, and the δ13C oscillations agreed well with anthropogenic pollution. In the range of 30°S-50°S, CO2 concentrations were generally low with relatively stable δ13C and δ18O values. In Antarctic Convergence Zone, a great difference of δ13C occurred between 10:00 and 22:00, and atmospheric CO2 was significantly depleted in 13C at 22:00. Our results indicated that the isotopic compositions of CO2 in the marine atmosphere might be a sensitive indicator for the strength of CO2 source and sink from the ocean.

  3. Automated determination of the stable carbon isotopic composition (δ13C) of total dissolved inorganic carbon (DIC) and total nonpurgeable dissolved organic carbon (DOC) in aqueous samples: RSIL lab codes 1851 and 1852

    Science.gov (United States)

    Révész, Kinga M.; Doctor, Daniel H.

    2014-01-01

    The purposes of the Reston Stable Isotope Laboratory (RSIL) lab codes 1851 and 1852 are to determine the total carbon mass and the ratio of the stable isotopes of carbon (δ13C) for total dissolved inorganic carbon (DIC, lab code 1851) and total nonpurgeable dissolved organic carbon (DOC, lab code 1852) in aqueous samples. The analysis procedure is automated according to a method that utilizes a total carbon analyzer as a peripheral sample preparation device for analysis of carbon dioxide (CO2) gas by a continuous-flow isotope ratio mass spectrometer (CF-IRMS). The carbon analyzer produces CO2 and determines the carbon mass in parts per million (ppm) of DIC and DOC in each sample separately, and the CF-IRMS determines the carbon isotope ratio of the produced CO2. This configuration provides a fully automated analysis of total carbon mass and δ13C with no operator intervention, additional sample preparation, or other manual analysis. To determine the DIC, the carbon analyzer transfers a specified sample volume to a heated (70 °C) reaction vessel with a preprogrammed volume of 10% phosphoric acid (H3PO4), which allows the carbonate and bicarbonate species in the sample to dissociate to CO2. The CO2 from the reacted sample is subsequently purged with a flow of helium gas that sweeps the CO2 through an infrared CO2 detector and quantifies the CO2. The CO2 is then carried through a high-temperature (650 °C) scrubber reactor, a series of water traps, and ultimately to the inlet of the mass spectrometer. For the analysis of total dissolved organic carbon, the carbon analyzer performs a second step on the sample in the heated reaction vessel during which a preprogrammed volume of sodium persulfate (Na2S2O8) is added, and the hydroxyl radicals oxidize the organics to CO2. Samples containing 2 ppm to 30,000 ppm of carbon are analyzed. The precision of the carbon isotope analysis is within 0.3 per mill for DIC, and within 0.5 per mill for DOC.

  4. Carbon and nitrogen stable isotope ratios and mercury concentration in the scalp hair of residents from Taiji, a whaling town

    International Nuclear Information System (INIS)

    Endo, Tetsuya; Hayasaka, Moriaki; Hisamichi, Yohsuke; Kimura, Osamu; Haraguchi, Koichi

    2013-01-01

    Highlights: ► We analyzed δ 13 C, δ 15 N and Hg in hair from Japanese whale meat-eaters and non-eaters. ► The δ 15 N and δ 13 C values in whale meat-eaters were higher than those in non-eaters. ► The Hg concentration in whale meat-eaters was higher than that in non-eaters. ► A positive correlation was seen between δ 15 N and Hg in whale meat-eaters. ► Consumption of whale meat may increase δ 15 N, δ 13 C and Hg in the scalp hair. -- Abstract: We analyzed stable isotope ratios of carbon (δ 13 C) and nitrogen (δ 15 N) as well as mercury (Hg) concentration in the scalp hair of Japanese who consumed whale meat and those who did not, and investigated the relationships among the δ 13 C and δ 15 N values and Hg concentration. The average δ 15 N and δ 13 C values of whale meat-eaters (10.11‰ and −18.5‰) were significantly higher than those of non-eaters (9.28‰ and −18.9‰), respectively. The average Hg concentration of whale meat-eaters (20.6 μg/g) was significantly higher than that of non-eaters (2.20 μg/g). Significant positive correlations were found between the δ 13 C and δ 15 N values and between the δ 15 N value and Hg concentration in the hair of whale meat-eaters, while the correlation between the δ 15 N value and Hg concentration was not statistically significant in the non-eaters. The consumption of whale meat may increase Hg concentration as well as δ 15 N and δ 13 C values in scalp hair

  5. Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

    NARCIS (Netherlands)

    Moerdijk-Poortvliet, Tanja C. W.; Schierbeek, Henk; Houtekamer, Marco; van Engeland, Tom; Derrien, Delphine; Stal, Lucas J.; Boschker, Henricus T. S.

    2015-01-01

    We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of δ(13)C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence, although

  6. Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

    NARCIS (Netherlands)

    Moerdijk-Poortvliet, T.C.W.; Schierbeek, H.; Houtekamer, M.; van Engeland, T.; Derrien, D.; Stal, L.J.; Boschker, H.T.S.

    2015-01-01

    We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of d13C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence, although

  7. Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

    NARCIS (Netherlands)

    Moerdijk-Poortvliet, T.C.W.; Schierbeek, H.; Houtekamer, M.; van Engeland, T.; Derrien, D.; Stal, L.J.; Boschker, H.T.S.

    2015-01-01

    Rationale: We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of δ13C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence,

  8. Influence of organic carbon sources and isotope exchange processes between water and nitrate on the fractionation of the stable isotopes {sup 15}N/{sup 14}N and {sup 18}O/{sup 16}O in dissolved nitrate during microbial dentrification in groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Wunderlich, Anja A.L.

    2012-11-02

    Stable isotopes of nitrate are commonly used to determine sources and degradation of nitrate. In this study, nitrite oxidizing bacteria were found to promote an oxygen isotope exchange between water and nitrate under anoxic conditions. Also, different carbon sources were found to influence the enrichment of stable isotopes in nitrate during microbial denitrification. Both results refine the stable isotope model of nitrate in respect to nitrate source determination and microbial nitrate reduction.

  9. Intercontinental correlation of organic carbon and carbonate stable isotope records: evidence of climate and sea-evel change during the Turonian (Cretaceous)

    Czech Academy of Sciences Publication Activity Database

    Jarvis, I.; Trabucho-Alexandre, J.; Gröcke, D. R.; Uličný, David; Laurin, Jiří

    2015-01-01

    Roč. 1, č. 2 (2015), s. 53-90 ISSN 2055-4877 R&D Projects: GA ČR GAP210/10/1991; GA MŠk LH12041 Institutional support: RVO:67985530 Keywords : carbon isotopes * chemostratigraphy * climate change * Cretaceous * oxygen isotopes Subject RIV: DB - Geology ; Mineralogy

  10. Improved constraints on in situ rates and on quantification of complete chloroethene degradation from stable carbon isotope mass balances in groundwater plumes

    Science.gov (United States)

    Höhener, Patrick; Elsner, Martin; Eisenmann, Heinrich; Atteia, Olivier

    2015-11-01

    Spills of chloroethenes (CEs) at industrial and urban sites can create groundwater plumes in which tetrachloro- and trichloroethene sequentially degrade to dichloroethenes, vinyl chloride (VC) and ethene, or ethane under reducing conditions. For detoxification, degradation must go beyond VC. Assessments based on ethene and ethane, however, are difficult because these products are volatile, may stem from alternative sources, can be further transformed and are not always monitored. To alternatively quantify degradation beyond VC, stable carbon isotope mass balances have been proposed where concentration-weighted CE isotope ratios are summed up and compared to the original source isotope ratio. Reported assessments, however, have provided not satisfactorily quantified results entailing greatly differing upper and lower estimates. This work proposes an integrative approach to better constrain the extent of total chloroethene degradation in groundwater samples. It is based on fitting of measured concentration and compound-specific stable carbon isotope data to an analytical reactive transport equation simulating steady-state plumes in two dimensions using an EXCEL spreadsheet. The fitting also yields estimates of degradation rates, of source width and of dispersivities. The approach is validated using two synthetic benchmark cases where the true extent of degradation is well known, and using data from two real field cases from literature.

  11. Organic synthesis with stable isotopes

    International Nuclear Information System (INIS)

    Daub, G.H.; Kerr, V.N.; Williams, D.L.; Whaley, T.W.

    1978-01-01

    Some general considerations concerning organic synthesis with stable isotopes are presented. Illustrative examples are described and discussed. The examples include DL-2-amino-3-methyl- 13 C-butanoic-3,4- 13 C 2 acid (DL-valine- 13 C 3 ); methyl oleate-1- 13 C; thymine-2,6- 13 C 2 ; 2-aminoethanesulfonic- 13 C acid (taurine- 13 C); D-glucose-6- 13 C; DL-2-amino-3-methylpentanoic-3,4- 13 C 2 acid (DL-isoleucine- 13 C 2 ); benzidine- 15 N 2 ; and 4-ethylsulfonyl-1-naphthalene-sulfonamide- 15 N

  12. The stable isotope composition of nitrogen and carbon and elemental contents in modern and fossil seabird guano from Northern Chile - Marine sources and diagenetic effects.

    Directory of Open Access Journals (Sweden)

    Friedrich Lucassen

    Full Text Available Seabird excrements (guano have been preserved in the arid climate of Northern Chile since at least the Pliocene. The deposits of marine organic material in coastal areas potentially open a window into the present and past composition of the coastal ocean and its food web. We use the stable isotope composition of nitrogen and carbon as well as element contents to compare the principal prey of the birds, the Peruvian anchovy, with the composition of modern guano. We also investigate the impact of diagenetic changes on the isotopic composition and elemental contents of the pure ornithogenic sediments, starting with modern stratified deposits and extending to fossil guano. Where possible, 14C systematics is used for age information. The nitrogen and carbon isotopic composition of the marine prey (Peruvian anchovy of the birds is complex as it shows strong systematic variations with latitude. The detailed study of a modern profile that represents a few years of guano deposition up to present reveals systematic changes in nitrogen and carbon isotopic composition towards heavier values that increase with age, i.e. depth. Only the uppermost, youngest layers of modern guano show compositional affinity to the prey of the birds. In the profile, the simultaneous loss of nitrogen and carbon occurs by degassing, and non-volatile elements like phosphorous and calcium are passively enriched in the residual guano. Fossil guano deposits are very low in nitrogen and low in carbon contents, and show very heavy nitrogen isotopic compositions. One result of the study is that the use of guano for tracing nitrogen and carbon isotopic and elemental composition in the marine food web of the birds is restricted to fresh material. Despite systematic changes during diagenesis, there is little promise to retrieve reliable values of marine nitrogen and carbon signatures from older guano. However, the changes in isotopic composition from primary marine nitrogen isotopic

  13. Stable carbon isotopic composition of tree rings from a pine tree from Augustów Wilderness, Poland, as a temperature and local environment conditions indicator.

    Science.gov (United States)

    Pawelczyk, Slawomira; Pazdur, Anna; Halas, Stanislaw

    2004-06-01

    Tree rings can be used as archives of climatic and environmental data with annual resolution. Tree rings widths, maximum late wood density and other parameters as stable composition in tree rings can be used for the reconstruction of past climatic and environmental changes. Stable carbon isotope ratios in tree rings may provide valuable information on past climatic conditions. 13C/12C ratios of plant organic matter can reflect corresponding 13C/12C ratio of atmospheric CO2 during formation of the rings. Investigations of isotopic carbon composition in tree rings from in the ecologically clean the Augustów Wilderness region in the north-eastern part of Poland (22 degrees 58'E, 53 degrees 51'N) (nowadays a sanctuary) were undertaken. Series of delta13C in alpha-cellulose and in wholewood were acquired. Those measurements constituted a part of more complex investigations of carbon isotope composition in tree rings including the measurements of radiocarbon concentration and tree ring widths. This article presents preliminary results. It is argued that contrary to the tree ring widths and delta13C in wholewood that do not reveal significant correlation with temperature, the variation of delta13C in the latewood alpha-cellulose is correlated with combined July and August temperatures. Copyright 2004 Taylor and Francis Ltd.

  14. Recycling of water, carbon, and sulfur during subduction of serpentinites: A stable isotope study of Cerro del Almirez, Spain

    Science.gov (United States)

    Alt, Jeffrey C.; Garrido, Carlos J.; Shanks, Wayne C.; Turchyn, Alexandra; Padrón-Navarta, José Alberto; López Sánchez-Vizcaíno, Vicente; Gómez Pugnaire, María Teresa; Marchesi, Claudio

    2012-01-01

    We use the concentrations and isotope compositions of water, carbon, and sulfur in serpentinites and their dehydration products to trace the cycling of volatiles during subduction. Antigorite serpentinites from the Cerro del Almirez complex, Spain, contain 9–12 wt.% H2O and 910 ± 730 ppm sulfur, and have bulk δ18O values of 8.6 ± 0.4‰, δD = − 54 ± 5‰, and δ34S = 5.0‰, consistent with serpentinization at temperatures of ~ 200 °C by seawater hydrothermal fluids in a seafloor setting. The serpentinites were dehydrated to chlorite–harzburgite (olivine + orthopyroxene + chlorite) at 700 °C and 1.6–1.9 GPa during subduction metamorphism, resulting in loss of water, and sulfur. The chlorite–harzburgites contain 5.7 ± 1.9 wt.% H2O, and have bulk δ18O = 8.0 ± 0.9‰, and δD = − 77 ± 11‰. The rocks contain 650 ± 620 ppm sulfur having δ34S = 1.2‰. Dehydration of serpentinite resulted in loss of 5 wt.% H2O having δ18O = 8–10‰ and δD = − 27 to − 65‰, and loss of 260 ppm sulfur as sulfate, having δ34S = 14.5‰. The contents and δ13C of total carbon in the two rock types overlap, with a broad trend of decreasing carbon contents and δ13C from ~ 1300 to 200 ppm and − 9.6 to − 20.2‰. This reflects mixing between reduced carbon in the rocks (210 ppm, δ13C ≈ − 26‰) and seawater-derived carbonate (δ13C ≈ − 1‰). Our results indicate: 1) Serpentinized oceanic peridotites carry significant amounts of isotopically fractionated water, carbon and sulfur into subduction zones; 2) Subduction of serpentinites to high P and T results in loss of water, and sulfur, which can induce melting and contribute to 18O, D, and 34S enrichments and oxidation of the sub-arc mantle wedge; and 3) Isotopically fractionated water, carbon, and sulfur in serpentinite dehydration products are recycled deeper into the mantle where they can contribute to isotope heterogeneities and may be significant for volatile budgets of the deep Earth.

  15. A reconstruction of atmospheric carbon dioxide and its stable carbon isotopic composition from the penultimate glacial maximum to the last glacial inception

    Directory of Open Access Journals (Sweden)

    R. Schneider

    2013-11-01

    δ13Catm level in the Penultimate (~ 140 000 yr BP and Last Glacial Maximum (~ 22 000 yr BP, which can be explained by either (i changes in the isotopic composition or (ii intensity of the carbon input fluxes to the combined ocean/atmosphere carbon reservoir or (iii by long-term peat buildup. Our isotopic data suggest that the carbon cycle evolution along Termination II and the subsequent interglacial was controlled by essentially the same processes as during the last 24 000 yr, but with different phasing and magnitudes. Furthermore, a 5000 yr lag in the CO2 decline relative to EDC temperatures is confirmed during the glacial inception at the end of MIS5.5 (120 000 yr BP. Based on our isotopic data this lag can be explained by terrestrial carbon release and carbonate compensation.

  16. Stable isotopes and biomarkers in microbial ecology

    NARCIS (Netherlands)

    Boschker, H.T.S.; Middelburg, J.J.

    2002-01-01

    The use of biomarkers in combination with stable isotope analysis is a new approach in microbial ecology and a number of papers on a variety of subjects have appeared. We will first discuss the techniques for analysing stable isotopes in biomarkers, primarily gas chromatography-combustion-isotope

  17. Paired carbon stable-isotope records for the Cenomanian Stage (100.5 -93.9 Ma): correlation tool and Late Cretaceous pCO2 record?

    Science.gov (United States)

    Jarvis, Ian; Gröcke, Darren; Laurin, Jiří; Selby, David; Roest-Ellis, Sascha; Miles, Andrew; Lignum, John; Gale, Andrew; Kennedy, Jim

    2016-04-01

    Carbon stable-isotope stratigraphy of marine carbonates (δ13Ccarb) provides remarkable insights into past variation in the global carbon cycle, and has become firmly established as a powerful global correlation tool. Continuous δ13Ccarb time series are becoming increasingly available for much of the geological record, including the Upper Cretaceous. However, our knowledge of stratigraphic variation in the carbon isotopic composition of sedimentary organic matter (δ13Corg) is much poorer, and is generally restricted to organic-rich sedimentary successions and/or key boundary intervals. Close coupling exists between the global isotopic composition of the reduced and oxidised carbon reservoirs on geological time scales, but the stratigraphic resolution of most long-term δ13Corg Mesozoic records is inadequate to identify leads and lags in the responses of the two reservoirs to carbon cycle perturbations. Cenomanian times (100.5-93.9 Ma) represent perhaps the best documented episode of eustatic rise in sea level in Earth history and the beginning of the Late Mesozoic thermal maximum, driving global expansion of epicontinental seas and the onset of widespread pelagic and hemipelagic carbonate deposition. Significant changes occurred in global stable-isotope records, including two prominent perturbations of the carbon cycle - the Mid-Cenomanian Event I (MCEI; ~96.5-96.2 Ma) and Oceanic Anoxic Event 2 (OAE2; ~94.5-93.8 Ma). OAE2, one of two truly global Cretaceous OAEs, was marked by the widespread deposition of black shales, and a global positive carbon stable-isotope excursion of 2.0 - 2.5‰ δ13Ccarb, and up to 7‰ in the sulphur-bound phytane biomarker. MCEI, by contrast, shows a English Chalk reference section at Folkestone, and correlate the carbon-isotope events between England, France, Germany and Italy. Comparison of the Vergons δ13Ccarb vs. δ13Corg profiles demonstrates similar medium-term stratigraphic variation, but significant differences in both short

  18. Carbon and nitrogen stable isotope ratios analysis of food sources for Chironomus acerbiphilus larvae (Diptera Chironomidae) in strongly acidic lake Katanuma

    Energy Technology Data Exchange (ETDEWEB)

    Doi, Hideyuki [Tohoku Univ., Sendai (Japan). Graduate School of Science; Kikuchi, Eisuke; Shikano, Shuichi

    2001-12-01

    The food sources for Chironomus acerbiphilus larvae (Diptera Chironomidae) were analyzed using carbon and nitrogen stable isotope ratios in Lake Katanuma. Lake Katanuma is a volcanic and strongly acidic lake (average pH 2.2). In Lake Katanuma, potential sources of diets for the chironomid larvae are limited including a benthic diatom (Pinnularia braunii), a phytoplankton (Chlamydomonas acidophila), sulfate oxidizing bacteria, and vascular plants supplied from vegetation surrounding the lake. Based on the average carbon and nitrogen isotope ratios among these potential sources and sediment, benthic diatoms were considered to be most probable food source of the chironomid larvae. {delta}{sup 13}C values of the chironomid were significantly different among seasons and habitat depths, suggesting that diet of C. acerbiphilus changed seasonally and with habitat depth. (author)

  19. Carbon and nitrogen stable isotope ratios analysis of food sources for Chironomus acerbiphilus larvae (Diptera Chironomidae) in strongly acidic lake Katanuma

    International Nuclear Information System (INIS)

    Doi, Hideyuki; Kikuchi, Eisuke; Shikano, Shuichi

    2001-01-01

    The food sources for Chironomus acerbiphilus larvae (Diptera Chironomidae) were analyzed using carbon and nitrogen stable isotope ratios in Lake Katanuma. Lake Katanuma is a volcanic and strongly acidic lake (average pH 2.2). In Lake Katanuma, potential sources of diets for the chironomid larvae are limited including a benthic diatom (Pinnularia braunii), a phytoplankton (Chlamydomonas acidophila), sulfate oxidizing bacteria, and vascular plants supplied from vegetation surrounding the lake. Based on the average carbon and nitrogen isotope ratios among these potential sources and sediment, benthic diatoms were considered to be most probable food source of the chironomid larvae. δ 13 C values of the chironomid were significantly different among seasons and habitat depths, suggesting that diet of C. acerbiphilus changed seasonally and with habitat depth. (author)

  20. Temporal variation in organic carbon stable isotope compositions of lacustrine sediments from sub-arid northern Tanzania

    International Nuclear Information System (INIS)

    Muzuka, A.N.N.; Nyandwi, N.

    2002-01-01

    The stable isotope compositions for four sediment cores recovered from three shallow lakes located in the Ngorongoro crater (Lake Magat) and head of the Olduvai Gorge (Lakes Ndutu and Messak) are used to document climatic changes in sub-arid northern Tanzania during the late Pleistocene-Holocene period. The two lakes, which are located on the head of the Olduvai Gorge about 1 km apart and 100 km from the Ngorongoro Crater, were probably once one lake during periods of high precipitation. All four cores were collected using a flow-through type of corer, and sub-sampled every 10 cm with each sample representing a homogenate of 1 cm. Two cores (40 cm and 500 cm long) were collected from Lake Magat, and AMS 14 C age on total organic matter (OM) for a nearby core collected about 1 m apart indicate that the sedimentation rate at these sites is approximately 17 cm/ka. Assuming that these sites have a constant rate of sedimentation, the analysed long core represents sediments that were deposited during the late Pleistocene-Holocene period. The δ 13 C for 40 cm long core shows a downcore increase, with δ-values ranging from -21 per mille to -12.5 per mille. A similar downcore increase in 13 C values is observable for the 500 cm long core. Apart from this general tend, this core also shows three peaks of low δ-values centred at 200 cm, 380 cm and 490 cm. A general downcore increase in the 13 C for the two cores from the Ngorongoro crater suggests changes in the relative proportion of C 3 and C 4 , probably indicating changes in precipitation and lake levels in the area. High precipitation and lake levels being associated with deposition of OM depleted in 13 C. Although, diagenetic changes might have contributed to the observed trend, but a change of up to 7 per mille cannot solely be attributed to diagenetic changes. High content of organic carbon and nitrogen in sections enriched in 13 C excludes the possibility of diagenetic effects. Although record from Lake Ndutu is

  1. Stable isotope enrichment: Current and future potential

    International Nuclear Information System (INIS)

    Tracy, J.G.; Aaron, W.S.

    1992-01-01

    Oak Ridge National Laboratory (ORNL) operates the Isotope Enrichment Facility for the purpose of providing enriched stable isotopes, selected radioactive isotopes (including the actinides), and isotope-related materials and services for use in various research applications. ORNL is responsible for isotope enrichment and the distribution of approximately 225 nongaseous stable isotopes from 50 multi-isotopic elements. Many enriched isotope products are of prime importance in the fabrication of nuclear targets and the subsequent production of special radionuclides. State-of-the-art techniques to achieve special isotopic, chemical, and physical requirements are performed at ORNL This report describes the status and capabilities of the Isotope Enrichment Facility and the Isotope Research Materials Laboratory as well as emphasizing potential advancements in enrichment capabilities

  2. Stable isotope enrichment - current and future potential

    International Nuclear Information System (INIS)

    Tracy, J.G.; Aaron, W.S.

    1993-01-01

    Oak Ridge National Laboratory (ORNL) operates the Isotope Enrichment Facility for the purpose of providing enriched stable isotopes, selected radioactive isotopes (including the actinides), and isotope-related materials and services for use in various research applications. ORNL is responsible for isotope enrichment and the distribution of approximately 225 nongaseous stable isotopes from 50 multi-isotopic elements. Many enriched isotope products are of prime importance in the fabrication of nuclear targets and the subsequent production of special radionuclides. State-of-the-art techniques to achieve special isotopic, chemical, and physical requirements are performed at ORNL. This report describes the status and capabilities of the Isotope Enrichment Facility and the Isotope Research Materials Laboratory as well as emphasizing potential advancements in enrichment capabilities. (orig.)

  3. Carbon sources and trophic structure in an eelgrass (Zostera marina L.) bed based on stable isotope and fatty acid analyses

    OpenAIRE

    Jaschinski, Sybill; Brepohl, Daniela C.; Sommer, Ulrich

    2008-01-01

    Multiple stable isotope and fatty acid analyses were applied to examine food web dynamics in an eelgrass Zostera marina L. system in the western Baltic Sea. Samples of eelgrass, epiphytic algae, sand microflora, red algae, phytoplankton and main consumer species were collected in June 2002. delta C-13 values of primary producers ranged from -9.6%. for eelgrass to the most depleted value of -34.9%. for the most abundant red alga, Delesseria sanguinea, Epiphyte delta C-13 (-11.3 parts per thous...

  4. Patterns in stable isotope values of nitrogen and carbon in particulate matter from the Northwest Atlantic Continental Shelf, from the Gulf of Maine to Cape Hatteras

    Directory of Open Access Journals (Sweden)

    Autumn Oczkowski

    2016-12-01

    Full Text Available Stable isotope measurements of nitrogen and carbon (δ15N, δ13C are often used to characterize estuarine, nearshore, and open ocean ecosystems. Reliable information about the spatial distribution of base-level stable isotope values, often represented by primary producers, is critical to interpreting values in these ecosystems. While base-level isotope data are generally readily available for estuaries, nearshore coastal waters, and the open ocean, the continental shelf is less studied. To address this, and as a first step towards developing a surrogate for base-level isotopic signature in this region, we collected surface and deep water samples from the United States’ eastern continental shelf in the Western Atlantic Ocean, from the Gulf of Maine to Cape Hatteras, periodically between 2000 and 2013. During the study, particulate matter δ15N values ranged from 0.8 to 17.4 ‰, and δ13C values from -26.4 to -15.6 ‰ over the region. We used spatial autocorrelation analysis and random forest modeling to examine the spatial trends and potential environmental drivers of the stable isotope values. We observed general trends towards lower values for both nitrogen and carbon isotopes at the seaward edge of the shelf. Conversely, higher δ15N and δ13C values were observed on the landward edge of the shelf, in particular in the southern portion of the sampling area. Across all sites, the magnitude of the difference between the δ15N of subsurface and surface particulate matter (PM significantly increased with water depth (r2 = 0.41, df = 35, p < 0.001, while δ13C values did not change. There were significant positive correlation between δ15N and δ13C values for surface PM in each of the three marine ecoregions that make up the study area. Stable isotope dynamics on the shelf can inform both nearshore and open ocean research efforts, reflecting regional productivity patterns and, even possibly, large-scale climate fluctuations.

  5. Effects of sewage contamination on macro-algae and shellfish at Moa Point, New Zealand, using stable carbon and nitrogen isotopes

    International Nuclear Information System (INIS)

    Rogers, K.M.

    1999-01-01

    Stable carbon and nitrogen isotopes have been used to characterise sewage discharge and effects on seaweed (Ulva lactuca L.), blue mussels (Mytilus galloprovincialis), and limpets (Cellana denticulata) from Moa Point Bay, New Zealand. The nitrogen ( 15 N / 14 N) ratio is shown to be a good tracer of sewage pollution in Ulva lactuca and associated grazers (Cellana denticulata) as a result of the increased contribution of urea and ammonia to the surrounding marine environment from the sewage outfall. The carbon ( 13 C / 12 C) ratio is suggested as a more appropriate sewer tracer for mussels (Mytilus galloprovincialis), which filter feed the particulate organic matter from the effluent. Lower carbon : nitrogen ratios were found in U. lactuca sampled from the outfall region, compared to uncontaminated control sites, however carbon : nitrogen ratios do not vary significantly amongst shellfish species. (author). 18 refs., 4 figs., 2 tabs

  6. Well-based stable carbon isotope leakage monitoring of an aquifer overlying the CO2 storage reservoir at the Ketzin pilot site, Germany

    Science.gov (United States)

    Nowak, Martin; Myrttinen, Anssi; Zimmer, Martin; van Geldern, Robert; Barth, Johannes A. C.

    2014-05-01

    At the pilot site for CO2 storage in Ketzin, a new well-based leakage-monitoring concept was established, comprising geochemical and hydraulic observations of the aquifer directly above the CO2 reservoir (Wiese et al., 2013, Nowak et al. 2013). Its purpose was to allow early detection of un-trapped CO2. Within this monitoring concept, we established a stable carbon isotope monitoring of dissolved inorganic carbon (DIC). If baseline isotope values of aquifer DIC (δ13CDIC) and reservoir CO2 (δ13CCO2) are known and distinct from each other, the δ13CDIC has the potential to serve as an an early indicator for an impact of leaked CO2 on the aquifer brine. The observation well of the overlying aquifer was equipped with an U-tube sampling system that allowed sampling of unaltered brine. The high alkaline drilling mud that was used during well drilling masked δ13CDIC values at the beginning of the monitoring campaign. However, subsequent monitoring allowed observing on-going re-equilibration of the brine, indicated by changing δ13CDIC and other geochemical values, until values ranging around -23 ‰ were reached. The latter were close to baseline values before drilling. Baselineδ13CDIC and δ13CCO2 values were used to derive a geochemical and isotope model that predicts evolution of δ13CDIC, if CO2 from the reservoir would leak into the aquifer. The model shows that equilibrium isotope fractionation would have to be considered if CO2 dissolves in the brine. The model suggests that stable carbon isotope monitoring is a suitable tool to assess the impact of injected CO2 in overlying groundwater aquifers. However, more data are required to close gaps of knowledge about fractionation behaviour within the CO2(g) - DIC system under elevated pressures and temperatures. Nowak, M., Myrttinen, A., Zimmer, M., Wiese, B., van Geldern, R., Barth, J.A.C., 2013. Well-based, Geochemical Leakage Monitoring of an Aquifer Immediately Above a CO2 Storage Reservoir by Stable Carbon

  7. Source apportionment of organic pollutants of a highway-traffic-influenced urban area in Bayreuth (Germany) using biomarker and stable carbon isotope signatures.

    Science.gov (United States)

    Glaser, Bruno; Dreyer, Annekatrin; Bock, Michael; Fiedler, Stefan; Mehring, Marion; Heitmann, Tobias

    2005-06-01

    Traffic- and urban-influenced areas are prone to enhanced pollution with products of incomplete combustion of fossil fuels and biomass such as black carbon or polycyclic aromatic hydrocarbons (PAHs). Black carbon is composed of aromatic and graphitic structures and may act as a carrier for pollutants such as PAHs and heavy metals. However, little is known about possible contributions of traffic-derived black carbon to the black carbon inventory in soils. Similar uncertainties exist regarding the contribution of different pollutant sources to total PAH and black carbon contents. Therefore, the objective of this study was to quantify the importance of traffic pollution to black carbon and PAH inventories in soils. PAH contamination of soils adjacent to a major German highway in the urban area of Bayreuth with about 50,000 vehicles per day was in the same order of magnitude compared to highway-close soils reported in other studies. Using molecular (black carbon and PAHs) and compound-specific stable carbon isotope evidence (PAHs) it was demonstrated that this contamination originated not only from automobile exhausts, here primarily diesel, but also from tire abrasion and tailpipe soot which significantly contributed to the traffic-caused black carbon and PAH contamination. Low molecular weight PAHs were more widely transported than their heavy molecular counterparts (local distillation), whereas highway-traffic-caused black carbon contamination was distributed to at least 30 m from the highway. On the other hand, urban fire exhausts were distributed more homogeneously among the urban area.

  8. Radiocarbon and stable carbon isotope compositions of chemically fractionated soil organic matter in a temperate-zone forest

    International Nuclear Information System (INIS)

    Koarashi, Jun; Iida, Takao; Asano, Tomohiro

    2005-01-01

    To better understand the role of soil organic matter in terrestrial carbon cycle, carbon isotope compositions in soil samples from a temperate-zone forest were measured for bulk, acid-insoluble and base-insoluble organic matter fractions separated by a chemical fractionation method. The measurements also made it possible to estimate indirectly radiocarbon ( 14 C) abundances of acid- and base-soluble organic matter fractions, through a mass balance of carbon among the fractions. The depth profiles of 14 C abundances showed that (1) bomb-derived 14 C has penetrated the first 16 cm mineral soil at least; (2) Δ 14 C values of acid-soluble organic matter fraction are considerably higher than those of other fractions; and (3) a significant amount of the bomb-derived 14 C has been preserved as the base-soluble organic matter around litter-mineral soil boundary. In contrast, no or little bomb-derived 14 C was observed for the base-insoluble fraction in all sampling depths, indicating that this recalcitrant fraction, accounting for approximately 15% of total carbon in this temperate-zone forest soil, plays a role as a long-term sink in the carbon cycle. These results suggest that bulk soil organic matter cannot provide a representative indicator as a source or a sink of carbon in soil, particularly on annual to decadal timescales

  9. Protein labelling with stable isotopes: strategies

    International Nuclear Information System (INIS)

    Lirsac, P.N.; Gilles, N.; Jamin, N.; Toma, F.; Gabrielsen, O.; Boulain, J.C.; Menez, A.

    1994-01-01

    A protein labelling technique with stable isotopes has been developed at the CEA: a labelled complete medium has been developed, performing as well as the Luria medium, but differing from it because it contains not only free aminated acids and peptides, but also sugars (96% of D-glucopyrannose) and labelled nucleosides. These precursors are produced from a labelled photosynthetic micro-organisms biomass, obtained with micro-algae having incorporated carbon 13, nitrogen 15 and deuterium during their culture. Labelling costs are reduced. 1 fig., 1 tab., 3 refs

  10. Continuous measurements of stable isotopes of carbon dioxide and water vapour in an urban atmosphere: isotopic variations associated with meteorological conditions.

    Science.gov (United States)

    Wada, Ryuichi; Matsumi, Yutaka; Nakayama, Tomoki; Hiyama, Tetsuya; Fujiyoshi, Yasushi; Kurita, Naoyuki; Muramoto, Kenichiro; Takanashi, Satoru; Kodama, Naomi; Takahashi, Yoshiyuki

    2017-12-01

    Isotope ratios of carbon dioxide and water vapour in the near-surface air were continuously measured for one month in an urban area of the city of Nagoya in central Japan in September 2010 using laser spectroscopic techniques. During the passages of a typhoon and a stationary front in the observation period, remarkable changes in the isotope ratios of CO 2 and water vapour were observed. The isotope ratios of both CO 2 and water vapour decreased during the typhoon passage. The decreases can be attributed to the air coming from an industrial area and the rainout effects of the typhoon, respectively. During the passage of the stationary front, δ 13 C-CO 2 and δ 18 O-CO 2 increased, while δ 2 H-H 2 Ov and δ 18 O-H 2 Ov decreased. These changes can be attributed to the air coming from rural areas and the air surrounding the observational site changing from a subtropical air mass to a subpolar air mass during the passage of the stationary front. A clear relationship was observed between the isotopic CO 2 and water vapour and the meteorological phenomena. Therefore, isotopic information of CO 2 and H 2 Ov could be used as a tracer of meteorological information.

  11. ASE extraction method for simultaneous carbon and nitrogen stable isotope analysis in soft tissues of aquatic organisms

    International Nuclear Information System (INIS)

    Bodin, Nathalie; Budzinski, Helene; Le Menach, Karyn; Tapie, Nathalie

    2009-01-01

    Since lipids are depleted in 13 C relative to proteins and carbohydrates, variations in lipid composition among species and within individuals significantly influence δ 13 C and may result in misleading ecological interpretations. Whereas lipid extraction before IRMS analysis constitutes a way of stable isotope result lipid-normalisation, such a procedure was given up because of the un-controlled effects of the methods used (i.e., 'Bligh and Dyer', Soxhlet, etc.) on δ 15 N. The aim of this work was to develop a simple, rapid and efficient lipid extraction method allowing for simultaneous C and N stable isotope analysis in the biological soft tissues of aquatic organisms. The goal was to be free from the lipid influence on δ 13 C values without interfering with δ 15 N values. For that purpose, the modern automated pressurized liquid extraction technique ASE (accelerated solvent extraction) was selected. Eel muscles representative of a broad range of fat contents were extracted via ASE by using different semi-polar solvents (100% dichloromethane and 80% n-hexane/20% acetone) and by operating at different temperature (ambient temperature and 100 deg. C) and pressure (750 and 1900 psi) conditions. The results were discussed in terms of lipid extraction efficiency as well as δ 13 C and δ 15 N variability.

  12. Assessing the Utility of Hydrogen, Carbon and Nitrogen Stable Isotopes in Estimating Consumer Allochthony in Two Shallow Eutrophic Lakes.

    Directory of Open Access Journals (Sweden)

    Jari Syväranta

    Full Text Available Hydrogen stable isotopes (δ2H have recently been used to complement δ13C and δ15N in food web studies due to their potentially greater power to separate sources of organic matter in aquatic food webs. However, uncertainties remain regarding the use of δ2H, since little is known about the potential variation in the amount of exchangeable hydrogen (Hex among common sample materials or the patterns of δ2H when entire food webs are considered. We assessed differences in Hex among the typical sample materials in freshwater studies and used δ2H, δ13C and δ15N to compare their effectiveness in tracing allochthonous matter in food webs of two small temperate lakes. Our results showed higher average amounts of Hex in animal tissues (27% in fish and macroinvertebrates, 19% in zooplankton compared to most plant material (15% in terrestrial plants and 8% in seston/periphyton, with the exception of aquatic vascular plants (23%, referred to as macrophytes. The amount of Hex correlated strongly with sample lipid content (inferred from C:N ratios in fish and zooplankton samples. Overall, the three isotopes provided good separation of sources (seston, periphyton, macrophytes and allochthonous organic matter, particularly the δ2H followed by δ13C. Aquatic macrophytes revealed unexpectedly high δ2H values, having more elevated δ2H values than terrestrial organic matter with direct implications for estimating consumer allochthony. Organic matter from macrophytes significantly contributed to the food webs in both lakes highlighting the need to include macrophytes as a potential source when using stable isotopes to estimate trophic structures and contributions from allochthonous sources.

  13. Periodicity of the stable isotopes

    CERN Document Server

    Boeyens, J C A

    2003-01-01

    It is demonstrated that all stable (non-radioactive) isotopes are formally interrelated as the products of systematically adding alpha particles to four elementary units. The region of stability against radioactive decay is shown to obey a general trend based on number theory and contains the periodic law of the elements as a special case. This general law restricts the number of what may be considered as natural elements to 100 and is based on a proton:neutron ratio that matches the golden ratio, characteristic of biological and crystal growth structures. Different forms of the periodic table inferred at other proton:neutron ratios indicate that the electronic configuration of atoms is variable and may be a function of environmental pressure. Cosmic consequences of this postulate are examined. (author)

  14. Carbon dioxide effects research and assessment program. Proceedings of the International Meeting on Stable Isotopes in Tree-Ring Research, New Paltz, New York, May 22-25, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Jacoby, G [ed.

    1980-12-01

    Information about the past and present concentrations of CO/sub 2/ in the atmosphere and variations in climate can be obtained from measurements of stable isotopes in tree rings; specifically carbon-13, oxygen-18 and deuterium. The analysis of these stable isotopes in tree rings is a relatively new and rapidly developing field. This proceedings volume contains most of the papers presented at the meeting. The first paper gives an overview of the status of carbon-13 research. Papers relating to carbon-13 are in section I and grouped separately from the contributions on carbon-14. Although the meeting was primarily concerned with stable isotopes, all carbon isotopic analysis may be helpful in understanding the carbon-13 record in tree rings. The papers on hydrogen and oxygen isotope studies are in sections II and III respectively. The remaining sections contain papers that consider more than one isotope at a time, general topics related to isotopes, atmospheric changes and tree growth, and methods of isotopic analysis.

  15. Using Stable Isotopes of Carbon and Nitrogen to Mark Wild Populations of Anopheles and Aedes Mosquitoes in South-Eastern Tanzania.

    Directory of Open Access Journals (Sweden)

    Mercy A Opiyo

    Full Text Available Marking wild mosquitoes is important for understanding their ecology, behaviours and role in disease transmission. Traditional insect marking techniques include using fluorescent dyes, protein labels, radioactive labels and tags, but such techniques have various limitations; notably low marker retention and inability to mark wild mosquitoes at source. Stable isotopes are gaining wide spread use for non-invasive marking of arthropods, permitting greater understanding of mosquito dispersal and responses to interventions. We describe here a simple technique for marking naturally-breeding malaria and dengue vectors using stable isotopes of nitrogen (15N and carbon (13C, and describe potential field applications.We created man-made aquatic mosquito habitats and added either 15N-labelled potassium nitrate or 13C-labelled glucose, leaving non-adulterated habitats as controls. We then allowed wild mosquitoes to lay eggs in these habitats and monitored their development in situ. Pupae were collected promptly as they appeared and kept in netting cages. Emergent adults (in pools of ~4 mosquitoes/pool and individually stored pupae were desiccated and analysed using Isotope Ratio Mass Spectrometry (IRMS.Anopheles gambiae s.l and Aedes spp. from enriched 13C and enriched 15N larval habitats had significantly higher isotopic levels than controls (P = 0.005, and both isotopes produced sufficient distinction between marked and unmarked mosquitoes. Mean δ15N for enriched females and males were 275.6±65.1 and 248.0±54.6, while mean δ15N in controls were 2.1±0.1 and 3.9±1.7 respectively. Similarly, mean δ13C for enriched females and males were 36.08±5.28 and 38.5±6.86, compared to -4.3±0.2 and -7.9±3.6 in controls respectively. Mean δ15N and δ13C was significantly higher in any pool containing at least one enriched mosquito compared to pools with all unenriched mosquitoes, P<0.001. In all cases, there were variations in standardized isotopic ratios

  16. Expanding the isotopic toolbox: Applications of hydrogen and oxygen stable isotope ratios to food web studies

    OpenAIRE

    Hannah B Vander Zanden; David X Soto; Gabriel J Bowen; Keith A Hobson; Keith A Hobson

    2016-01-01

    The measurement of stable carbon (δ13C) and nitrogen (δ15N) isotopes in tissues of organisms has formed the foundation of isotopic food web reconstructions, as these values directly reflect assimilated diet. In contrast, stable hydrogen (δ2H) and oxygen (δ18O) isotope measurements have typically been reserved for studies of migratory origin and paleoclimate reconstruction based on systematic relationships between organismal tissue and local environmental water. Recently, innovative applicat...

  17. Expanding the Isotopic Toolbox: Applications of Hydrogen and Oxygen Stable Isotope Ratios to Food Web Studies

    OpenAIRE

    Vander Zanden, Hannah B.; Soto, David X.; Bowen, Gabriel J.; Hobson, Keith A.

    2016-01-01

    The measurement of stable carbon (δ13C) and nitrogen (δ15N) isotopes in tissues of organisms has formed the foundation of isotopic food web reconstructions, as these values directly reflect assimilated diet. In contrast, stable hydrogen (δ2H) and oxygen (δ18O) isotope measurements have typically been reserved for studies of migratory origin and paleoclimate reconstruction based on systematic relationships between organismal tissue and local environmental water. Recently, innovative applicatio...

  18. Protein-based stable isotope probing.

    Science.gov (United States)

    Jehmlich, Nico; Schmidt, Frank; Taubert, Martin; Seifert, Jana; Bastida, Felipe; von Bergen, Martin; Richnow, Hans-Hermann; Vogt, Carsten

    2010-12-01

    We describe a stable isotope probing (SIP) technique that was developed to link microbe-specific metabolic function to phylogenetic information. Carbon ((13)C)- or nitrogen ((15)N)-labeled substrates (typically with >98% heavy label) were used in cultivation experiments and the heavy isotope incorporation into proteins (protein-SIP) on growth was determined. The amount of incorporation provides a measure for assimilation of a substrate, and the sequence information from peptide analysis obtained by mass spectrometry delivers phylogenetic information about the microorganisms responsible for the metabolism of the particular substrate. In this article, we provide guidelines for incubating microbial cultures with labeled substrates and a protocol for protein-SIP. The protocol guides readers through the proteomics pipeline, including protein extraction, gel-free and gel-based protein separation, the subsequent mass spectrometric analysis of peptides and the calculation of the incorporation of stable isotopes into peptides. Extraction of proteins and the mass fingerprint measurements of unlabeled and labeled fractions can be performed in 2-3 d.

  19. Carbon and oxygen stable isotope data as paleoenvironmental indicators for limestones from the Campos, Santos and Espirito Santo Basins, Brazil

    International Nuclear Information System (INIS)

    Takaki, T.; Rodrigues, R.

    1984-01-01

    Carbon and oxygen isotope data of limestones from Campos, Santos and Espirito Santo basins provided additional information on the sedimentation environments of these carbonates. The predominance of δ 13 C values between + 1,0 per mille and - 1,0 per mille samples from the Tertiary and the middle section of the Jiquia Stage (Lower Cretaceous) could indiccate, for both carbonate sequences, deposition in a normal marine environment. However, the absence of marine fossils in the Jiquia Stage but not in the Tertiary allows to suggest a normal marine environment for the latter and saline lakes for the former. More positive δ 13 C values in the upper portion of the Jiquia Stage and in the Alagoas Stage suggest a restricted marine environment, with a tendency to hypersalinity. During the Albian the carbonate sedimentation could have occurred in a marine enrironment with an above normal salinity, as indicated by values of δ 13 C between + 3,0 per mille and + 4,0 per mille. According to δ 18 O data, the surface waters were warm, with a tendency of becoming gradually cooler towards the top of the Tertiary. (Author) [pt

  20. Stable carbon isotope analysis of soil organic matter illustrates vegetation change at the grassland/woodland boundary in southeastern Arizona, USA.

    Science.gov (United States)

    McPherson, G R; Boutton, T W; Midwood, A J

    1993-02-01

    In southeastern Arizona, Prosopis juliflora (Swartz) DC. and Quercus emoryi Torr. are the dominant woody species at grassland/woodland boundaries. The stability of the grassland/woodland boundary in this region has been questioned, although there is no direct evidence to confirm that woodland is encroaching into grassland or vice versa. We used stable carbon isotope analysis of soil organic matter to investigate the direction and magnitude of vegetation change along this ecotone. δ 13 C values of soil organic matter and roots along the ecotone indicated that both dominant woody species (C 3 ) are recent components of former grasslands (C 4 ), consistent with other reports of recent increases in woody plant abundance in grasslands and savannas throughout the world. Data on root biomass and soil organic matter suggest that this increase in woody plant abundance in grasslands and savannas may increase carbon storage in these ecosystems, with implications for the global carbon cycle.

  1. Stable isotope views on ecosystem function: challenging or challenged?

    Science.gov (United States)

    Resco, Víctor; Querejeta, José I; Ogle, Kiona; Voltas, Jordi; Sebastià, Maria-Teresa; Serrano-Ortiz, Penélope; Linares, Juan C; Moreno-Gutiérrez, Cristina; Herrero, Asier; Carreira, José A; Torres-Cañabate, Patricia; Valladares, Fernando

    2010-06-23

    Stable isotopes and their potential for detecting various and complex ecosystem processes are attracting an increasing number of scientists. Progress is challenging, particularly under global change scenarios, but some established views have been challenged. The IX meeting of the Spanish Association of Terrestrial Ecology (AAET, Ubeda, 18-22 October 2009) hosted a symposium on the ecology of stable isotopes where the linear mixing model approach of partitioning sinks and sources of carbon and water fluxes within an ecosystem was challenged, and new applications of stable isotopes for the study of plant interactions were evaluated. Discussion was also centred on the need for networks that monitor ecological processes using stable isotopes and key ideas for fostering future research with isotopes.

  2. Stable isotope views on ecosystem function: challenging or challenged?

    Science.gov (United States)

    Resco, Víctor; Querejeta, José I.; Ogle, Kiona; Voltas, Jordi; Sebastià, Maria-Teresa; Serrano-Ortiz, Penélope; Linares, Juan C.; Moreno-Gutiérrez, Cristina; Herrero, Asier; Carreira, José A.; Torres-Cañabate, Patricia; Valladares, Fernando

    2010-01-01

    Stable isotopes and their potential for detecting various and complex ecosystem processes are attracting an increasing number of scientists. Progress is challenging, particularly under global change scenarios, but some established views have been challenged. The IX meeting of the Spanish Association of Terrestrial Ecology (AAET, Úbeda, 18–22 October 2009) hosted a symposium on the ecology of stable isotopes where the linear mixing model approach of partitioning sinks and sources of carbon and water fluxes within an ecosystem was challenged, and new applications of stable isotopes for the study of plant interactions were evaluated. Discussion was also centred on the need for networks that monitor ecological processes using stable isotopes and key ideas for fostering future research with isotopes. PMID:20015858

  3. Development of a non-destructive micro-analytical method for stable carbon isotope analysis of transmission electron microscope (TEM) samples

    Energy Technology Data Exchange (ETDEWEB)

    Hode, Tomas [Department of Geology, Portland State University, Portland, P.O. Box 751, OR 97201 (United States)], E-mail: hode@pdx.edu; Kristiansson, Per; Elfman, Mikael [Division of Nuclear Physics, Department of Physics, Lund Institute of Technology, Lund University, P.O. Box 118, SE-221 00 Lund (Sweden); Hugo, Richard C.; Cady, Sherry L. [Department of Geology, Portland State University, Portland, P.O. Box 751, OR 97201 (United States)

    2009-10-01

    The biogenicity of ancient morphological microfossil-like objects can be established by linking morphological (e.g. cell remnants and extracellular polymeric matrix) and chemical (e.g. isotopes, biomarkers and biominerals) evidence indicative of microorganisms or microbial activity. We have developed a non-destructive micro-analytical ion beam system capable of measuring with high spatial resolution the stable carbon isotope ratios of thin samples used for transmission electron microscopy. The technique is based on elastic scattering of alpha particles with an energy of 2.751 MeV. At this energy the {sup 13}C cross section is enhanced relative to the pure Rutherford cross section for {sup 13}C, whereas the {sup 12}C cross section is reduced relative to its pure Rutherford cross section. Here we report the initial results of this experimental approach used to characterize ultramicrotomed sections of sulfur-embedded graphite and microbial cells.

  4. Stable carbon isotope analysis (δ13C values) of polybrominated diphenyl ethers and their UV-transformation products

    International Nuclear Information System (INIS)

    Rosenfelder, Natalie; Bendig, Paul; Vetter, Walter

    2011-01-01

    Polybrominated diphenyl ethers (PBDEs) are frequently detected in food and environmental samples. We used compound specific isotope analysis to determine the δ 13 C values of individual PBDEs in two technical mixtures. Within the same technical product (DE-71 or DE-79), BDE congeners were the more depleted in 13 C the higher brominated they were. In contrast, the products of light-induced hydrodebromination of BDE 47 and technical DE-79 were more enriched in 13 C because of more stable bonds between 13 C and bromine. As a result, the δ 13 C values of the irradiated solution progressed diametrically compared to those of the technical synthesis. The ratio of the δ 13 C values of BDE 47 to BDE 99 and of BDE 99 to BDE 153 are thus suggested as indicators to distinguish native technical products from transformation products. Ratios 1) is typical of transformation products. - Highlights: → δ 13 C values of PBDEs were determined by means of compound specific isotope analysis. → PBDEs in technical mixtures were the more depleted in 13 C the higher they were brominated. → Solutions of individual PBDEs and technical PBDE mixtures were irradiated by UV light. → δ 13 C values of irradiated PBDEs and technical PBDEs progressed diametrically. → Ratios of the δ 13 C values were used to distinguish native from transformed PBDEs. - Diametrically progressing δ 13 C values in technical mixtures and UV-transformation products of DE-79 may be useful for source appointment of PBDEs in environmental samples

  5. Adaptation of benthic invertebrates to food sources along marine-terrestrial boundaries as indicated by carbon and nitrogen stable isotopes

    Science.gov (United States)

    Lange, G.; Haynert, K.; Dinter, T.; Scheu, S.; Kröncke, I.

    2018-01-01

    Frequent environmental changes and abiotic gradients of the Wadden Sea require appropriate adaptations of the local organisms and make it suitable for investigations on functional structure of macrozoobenthic communities from marine to terrestrial boundaries. To investigate community patterns and food use of the macrozoobenthos, a transect of 11 stations was sampled for species number, abundance and stable isotope values (δ13C and δ15N) of macrozoobenthos and for stable isotope values of potential food resources. The transect was located in the back-barrier system of the island of Spiekeroog (southern North Sea, Germany). Our results show that surface and subsurface deposit feeders, such as Peringia ulvae and different oligochaete species, dominated the community, which was poor in species, while species present at the transect stations reached high abundance. The only exception was the upper salt marsh with low abundances but higher species richness because of the presence of specialized semi-terrestrial and terrestrial taxa. The macrozoobenthos relied predominantly on marine resources irrespective of the locality in the intertidal zone, although δ13C values of the consumers decreased from - 14.1 ± 1.6‰ (tidal flats) to - 21.5 ± 2.4‰ (salt marsh). However, the ubiquitous polychaete Hediste diversicolor showed a δ15N enrichment of 2.8‰ (an increase of about one trophic level) from bare sediments to the first vegetated transect station, presumably due to switching from suspension or deposit feeding to predation on smaller invertebrates. Hence, we conclude that changes in feeding mode represent an important mechanism of adaptation to different Wadden Sea habitats.

  6. Composition of Hydrothermal Vent Microbial Communities as Revealed by Analyses of Signature Lipids, Stable Carbon Isotopes and Aquificales Cultures

    Science.gov (United States)

    Jahnke, Linda L.; Edger, Wolfgang; Huber, Robert; Hinrichs, Kai-Uwe; Hayes, John M.; DesMarais, David J.; Cady, Sherry; Hope, Janet M.; Summons, Roger E.; DeVincenzi, Donald L. (Technical Monitor)

    2001-01-01

    Extremely thermophilic microbial communities associated with the siliceous vent walls and outflow channel of Octopus Spring, Yellowstone National Park, have been examined for lipid biomarkers and carbon isotopic signatures. These data were compared with that obtained from representatives of three Aquificales genera. Thermocrinis ruber. "Thermocrinis sp. HI", Hydrogenobacter thermophilus TK-6, Aquifex pyrophilus and Aquifex aeolicus all contained phospholipids composed not only of the usual ester-linked fatty acids, but also ether-linked alkyls. The fatty acids of all cultured organisms were dominated by a very distinct pattern of n-C-20:1 and cy-C-21 compounds. The alkyl glycerol ethers were present primarily as CIS() monoethers with the expection of the Aquifex spp. in which dialkyl glycerol ethers with a boarder carbon-number distribution were also present. These Aquificales biomarker lipids were the major constituents in the lipid extracts of the Octopus Spring microbial samples. Two natural samples, a microbial biofilm growing in association with deposition of amorphous silica on the vent walls at 92 C, and the well-known 'pink-streamers community' (PSC), siliceous filaments of a microbial consortia growing in the upper outflow channel at 87 C were analyzed. Both the biofilm and PSC samples contained mono and dialkyl glycerol ethers with a prevalence of C-18 and C-20 alkyls. Phospholipid fatty acids were comprised of both the characteristic Aquificales n-C-20:1 and cy-C-21, and in addition, a series of iso-branched fatty acids from i-C-15:0 to i-C-21:0, With i-C-17:0 dominant in the PSC and i-C-19:0 in the biofilm, suggesting the presence of two major bacterial groups. Bacteriohopanepolyols were absent and the minute quantities of archaeol detected showed that Archaea were only minor constituents. Carbon isotopic compositions of the PSC yielded information about community structure and likely physiology. Biomass was C-13-depleted (10.9%) relative to available

  7. The Stable Isotopes of Carbon and Nitrogen in the Bones of Domestic Animals from three Cities of the European Part of Russia: First Results and Interpretations

    Directory of Open Access Journals (Sweden)

    Yavorskaya Liliya Vyacheslavovna

    2015-03-01

    Full Text Available The paper outlines the results of first purposeful research on isotopic composition (carbon 13С and nitrogen 15N in the bones collagen of domestic and wild animals from medieval towns at the European part of Russia. The published information about δ 13С и δ 15N was obtained from 61 samples of osteological collections of Yaroslavl, Rostov and Bolgar. The average values of carbon isotope in cattle bones are almost the same in all three cities. By contrast, these values for horses and pigs from Rostov and Bolgar are higher than for Yaroslavl animals. Unusual similarity for δ13С in the bones of sheep, camels and dogs among themselves from the Bolgar collection were fixed. The comparative analysis of the values δ13С in bones of domestic and wild animals allowed us to propose the hypothesis that sheep, camels and dogs appeared in Bolgar from the southern arid areas. The data on δ15N showed the inexplicably high accumulation of the nitrogen stable isotope in sheep and camel bones from the collection of Bolgar and in beaver bones from Rostov samples. This is probably due to the peculiarities of the diet of these dogs, enriched by the entrails of domestic ungulates or fish. The minimum values of δ15N in the bones of dogs from Bolgar reflect the specific diet of herding dogs with a minimal volume of meat. Simultaneously the data of 15N in sheep and camel bones from Bolgar collection and in beaver bones from Rostov samples howed the inexplicably high level of nitrogen stable isotope accumulation.

  8. Development of stable isotope manufacturing in Russia

    International Nuclear Information System (INIS)

    Pokidychev, A.; Pokidycheva, M.

    1999-01-01

    For the past 25 years, Russia has relied heavily on the electromagnetic separation process for the production of middle and heavy mass stable isotopes. The separation of most light isotopes had been centered in Georgia which, after the collapse of the USSR, left Russia without this capability. In the mid-1970s, development of centrifuge technology for the separation of stable isotopes was begun. Alternative techniques such as laser separation, physical-chemical methods, and ion cyclotron resonance have also been investigated. Economic considerations have played a major role in the development and current status of the stable isotope enrichment capabilities of Russia

  9. Applications of stable isotopes in clinical pharmacology

    NARCIS (Netherlands)

    Schellekens, Reinout C A; Stellaard, Frans; Woerdenbag, Herman J; Frijlink, Henderik W; Kosterink, Jos G W

    2011-01-01

    This review aims to present an overview of the application of stable isotope technology in clinical pharmacology. Three main categories of stable isotope technology can be distinguished in clinical pharmacology. Firstly, it is applied in the assessment of drug pharmacology to determine the

  10. Gas phase thermal diffusion of stable isotopes

    International Nuclear Information System (INIS)

    Eck, C.F.

    1979-01-01

    The separation of stable isotopes at Mound Facility is reviewed from a historical perspective. The historical development of thermal diffusion from a laboratory process to a separation facility that handles all the noble gases is described. In addition, elementary thermal diffusion theory and elementary cascade theory are presented along with a brief review of the uses of stable isotopes

  11. An assessment, using stable isotopes, of the importance of allochthonous organic carbon sources to the pelagic food web in Loch Ness

    Science.gov (United States)

    Jones, R. I.; Grey, J.; Sleep, D.; Quarmby, C.

    1998-01-01

    The natural abundance of stable isotopes (δ13C and δ1315N) was determined for components of the pelagic food web in Loch Ness, a deep oligotrophic lake in northern Scotland, and compared with values from the inflow rivers and the catchment vegetation. Phytoplankton δ13C was low compared to values reported from other lakes, possibly reflecting a high use of 13C-depleted carbon dioxide from respired organic matter before further isotopic fractionation during photosynthesis. Phytoplankton δ13C was appreciably lower than that of dissolved and particulate organic matter (DOM and POM) in the loch. The DOM and POM were evidently overwhelmingly of allochthonous origin and ultimately derived from terrestrial plant detritus. The distinctive δ13C values for phytoplankton and detritus in the loch allowed the use of food sources by grazing crustacean zooplankton to be assessed, and the contributions of phytoplankton carbon and detrital carbon to zooplankton total body carbon appeared to be about equal. Comparison of δ13C and δ15N values for zooplankton and fish allowed assessment of trophic structure in the loch. The very high dependence of the pelagic food web in Loch Ness on allochthonous organic matter inputs from the catchment may be exceptional in a large lake, but has important implications for our understanding of lake ecosystem processes as well as for lake management.

  12. Paleoecologies and paleoclimates of late cenozoic mammals from Southwest China: Evidence from stable carbon and oxygen isotopes

    Science.gov (United States)

    Biasatti, Dana; Wang, Yang; Gao, Feng; Xu, Yingfeng; Flynn, Lawrence

    2012-01-01

    To examine paleodiets and habitats of extinct taxa and to understand long-term regional climate change, we determined the carbon and oxygen isotopic compositions of fossil herbivore teeth and soil samples from six localities in Yunnan Province, Southwest China, ranging in age from ˜10 Ma to the present. Although limited in spatial and temporal coverage, these initial results reveal significant changes in the environments and diets of mammalian taxa over the last 10 million years. Prior to 2-3 Ma, while most mammals examined had pure or nearly pure C 3 diets, some individuals consumed a small amount of C 4 grasses (up to 20% C 4). Since then, C 4 grasses became a significant dietary component for most herbivores as indicated by higher enamel-δ 13C values in the Pleistocene Yuanmou Formation and at Shangri-La, most likely reflecting an increased C 4 biomass in the region. The carbon isotope results show that the diets of mammals of ˜2.5-1.75 Ma from Shangri-La ranged from pure C 3 to pure C 4 while 1.7 Ma horses from Yuanmou had 0-70% C 4 grasses in their diets. Mammals living at ˜8-7 Ma in the Yuanmou and Lufeng region had very similar diets and habitats, with similar climatic conditions. Increased C 4 biomass after ˜3-4 Ma suggests a significant change in certain aspects of regional climate, such as increased seasonality of rainfall or an increase in seasonal drought and fires as these factors are important to modern grasslands. The data also show that unlike the Siwalik fauna in the Indian subcontinent, mammals in Yunnan on the southeast side of the Himalayan-Tibetan Plateau lived in an environment dominated by dense forests until ˜3-4 Ma. Nonetheless, both δ 13C values of paleosol carbonates and fossil enamels indicate that C 4 grasses were present in the Yuanmou region in the latest Miocene and Pliocene (˜8-3.5 Ma), likely in greatly dispersed, small patches of open habitats where the forest canopy was broken or on flood plains, and the C 4 biomass

  13. Study and validity of 13C stable carbon isotopic ratio analysis by mass spectrometry and 2H site-specific natural isotopic fractionation by nuclear magnetic resonance isotopic measurements to characterize and control the authenticity of honey

    International Nuclear Information System (INIS)

    Cotte, J.F.; Casabianca, H.; Lheritier, J.; Perrucchietti, C.; Sanglar, C.; Waton, H.; Grenier-Loustalot, M.F.

    2007-01-01

    Honey samples were analyzed by stable carbon isotopic ratio analysis by mass spectrometry (SCIRA-MS) and site-specific natural isotopic fractionation measured by nuclear magnetic resonance (SNIF-NMR) to first determine their potentials for characterizing the substance and then to combat adulteration. Honey samples from several geographic and botanical origins were analyzed. The δ 13 C parameter was not significant for characterizing an origin, while the (D/H) I ratio could be used to differentiate certain single-flower varieties. Application of the official control method of adding a C 4 syrup (AOAC official method 998.12) to our authentic samples revealed anomalies resulting from SCIRA indices that were more negative than -1 per mille (permil). A filtration step was added to the experimental procedure and provided results that were compliant with Natural origin of our honey samples. In addition, spiking with a C 4 syrup could be detected starting at 9-10%. The use of SNIF-NMR is limited by the detection of a syrup spike starting only at 20%, which is far from satisfying

  14. Rare stable isotopes in meteorites

    International Nuclear Information System (INIS)

    Wilson, G.C.

    1981-01-01

    Secondary Ion Mass Spectrometry (SIMS) using accelerators has been applied with success to cosmic ray exposure ages and terrestrial residence times of meteorites by measuring cosmogenic nuclides of Be, Cl, and I. It is proposed to complement this work with experiments on rare stable isotopes, in the hope of setting constraints on the processes of solar nebula/meteoritic formation. The relevant species can be classified as: a) daughter products of extinct nuclides (halflife less than or equal to 2 x 10 8 y) -chronology of the early solar system; b) products of high temperature astrophysical processes - different components incorporated into the solar nebula; and c) products of relatively low temperature processes, stellar winds and cosmic ray reactions - early solar system radiation history. The use of micron-scale primary ion beams will allow detailed sampling of phases within meteorites. Strategies of charge-state selection, molecular disintegration and detection should bring a new set of targets within analytical range. The developing accelerator field is compared to existing (keV energy) ion microprobes

  15. Stable carbon isotope ratios as indicators of marine versus terrestrial inputs to the diets of wild and captive tuatara (Sphenodon punctatus)

    International Nuclear Information System (INIS)

    Cree, A.; Cartland-Shaw, L.; Tyrrell, C.; Lyon, G.L.

    1999-01-01

    Stable carbon isotope analysis was used to examine feeding relationships of wild tuatara on Stephens Island and captive tuatara in New Zealand institutions. We first measured delta 13 C in three food items of wild tuatara. Pectoral muscle of fairy prions (a seabird eaten seasonally by tuatara) was significantly enriched in 13 C compared with whole bodies of wild insects (darkling beetles and tree weta). Values for delta 13 C in blood cells varied significantly among wild tuatara of different life-history stages. Male tuatara were more enriched in 13 C than were females or juveniles, suggesting that males prey more heavily on seabirds. Insect foods of captive tuatara varied dramatically in delta/sup 13/C; this is attributed to differential consumption of plant material derived from the C 3 and C 4 photosynthetic pathways. Blood cells from four different groups of captive tuatara differed significantly in delta 13 C. This was perhaps related to assimilation of insects with different delta 13 C values, and cannot be attributed to differences in seabird predation as captive tuatara do not have access to seabirds. For wild tuatara on Stephens Island, stable carbon isotope analysis provides support for the dietary information available from behavioural observations, gut analyses and measurements of plasma composition. (author). 47 refs., 1 tab., 2 figs

  16. Combined Stable Carbon Isotope and C/N Ratios as Indicators of Source and Fate of Organic Matter in the Bang Pa kong River Estuary, Thailand

    International Nuclear Information System (INIS)

    Boonphakdee, Thanomsak; Kasai, Akihide; Fujiwara, Tateki; Sawangwong, Pichan; Cheevaporn, Voravit

    2007-08-01

    Full text: Stable carbon isotopes and C/N ratios of particulate organic matter (POM) in suspended solids and surficial sediment were used to define the spatial and temporal variability in an anthropogenic tropical river estuary, the Bang Pa kong River Estuary. Samples were taken along salinity gradients during the four different river discharges in the beginning, high river discharge and at the end of the wet season, and low river discharge during the dry season. The values of [C/N]a ratio and d13C in the river estuary revealed significant differences from those of the offshore station. Conservative behaviors of [C/N]a and d13C in the estuary during the wet season indicated major contribution of terrigenous C3 plants derived OM. By contrast, during the dry season, marine input mainly dominated OM contribution with an evidence of anthropogenic input to the estuary. These compositions of the bulk sedimentary OM were dominated by paddy rice soils and marine derived OM during the wet and dry seasons, respectively. These results show that the combined stable carbon isotopes and C/N ratios can be used to identify the source and fate of OM even in a river estuary. This tool will be useful to achieve sustainable management in coastal zone

  17. Application of Stable Isotope Signatures in Food Traceability

    International Nuclear Information System (INIS)

    Nazaratul Ashifa Abdullah Salim; Roslanzairi Mostapha; Zainon Othman; Nor Afiqah Harun; Mohd Suhaimi Hamzah; Shamsiah Abdul Rahman; Md Suhaimi Elias; Salmah Moosa

    2015-01-01

    Stable isotope analysis has widely been used to trace the origin of organic materials in various fields, such as geochemistry, biochemistry, archaeology and petroleum. In past a decade, it has also become an important tool for food traceability study. The globalization of food markets and the relative ease with which food commodities are transported through and between countries and continents, means that consumers are increasingly concerned about the origin of the foods they eat. The natural abundance isotope variation such as carbon, nitrogen, hydrogen and oxygen are use as geographic tracers or marker to determine the geographic origin of fruits, crop, vegetables and food products from animal. The isotopic compositions of plant materials reflect various factors such as isotopic compositions of source materials and their assimilation processes as well as growth environments. This paper will discuss on stable carbon and nitrogen isotopic compositions in rice, advantages, limitations and potential of other analysis applications that can be incorporated in food traceability system. (author)

  18. Carbon stable isotope-climate association in tree rings of Pinus pinaster and Pinus sylvestris in Mediterranean environments

    International Nuclear Information System (INIS)

    Bogino, Stella M; Bravo, Felipe

    2014-01-01

    Carbon isotope ratios, recorded as "1"3C/"1"2C variations in tree rings of woody species, are the result of physiological changes related to environmental conditions. The objective of this work was to analyze the association among carbon thirteen variability (δ"1"3C), climate variables and tree-ring growth of Pinus pinaster and Pinus sylvestris in central Spain. Pulverized woody material from the period 1975-1999 from four trees for each pine species was analyzed. To detect common patterns in δ"1"3C within each species and between δ"1"3C and growth indices, a principal component analysis (PCA) was performed. δ"1"3C of trees and the residual tree-ring chronologies were used at the PCA. Multilevel mixed linear models were applied between intrinsic water use efficiency (iWUE) and climate variables. Our results show an inverse significant correlation between δ"1"3C and tree-ring growth of both species. Winter and spring air moisture was negatively correlated with iWUE of Pinus pinaster. July maximum temperature was positively correlated with iWUE of Pinus sylvestris. As δ"1"3C is significantly related to climate and growth and it may be recommended as a valuable tool for tree growth dynamic analysis to withstand increasingly stressful climate conditions

  19. Carbon and nitrogen stable isotopes and metal concentration in food webs from a mining-impacted coastal lagoon

    International Nuclear Information System (INIS)

    Marin-Guirao, Lazaro; Lloret, Javier; Marin, Arnaldo

    2008-01-01

    Two food webs from the Mar Menor coastal lagoon, differing in the distance from the desert-stream through which mining wastes were discharged, were examined by reference to essential (Zn and Cu) and non-essential (Pb and Cd) metal concentrations and stable isotopes content (C and N). The partial extraction technique applied, which reflects the availability of metals to organisms after sediment ingestion, showed higher bioavailable metal concentrations in sediments from the station influenced by the mining discharges, in agreement with the higher metal concentrations observed in organisms, which in many cases exceeded the regulatory limits established in Spanish legislation concerning seafood. Spatial differences in essential metal concentrations in the fauna suggest that several organisms are exposed to metal levels above their regulation capacity. Differences in isotopic composition were found between both food webs, the wadi-influenced station showing higher δ 15 N values and lower δ 13 C levels, due to the discharge of urban waste waters and by the entrance of freshwater and allochthonous marsh plants. The linear-regressions between trophic levels (as indicated by δ 15 N) and the metal content indicated that biomagnification does not occur. In the case of invertebrates, since the 'handle strategy' of the species and the physiological requirements of the organisms, among other factors, determine the final concentration of a specific element, no clear relationships between trophic level and the metal content are to be expected. For their part, fish communities did not show clear patterns in the case of any of the analyzed metals, probably because most fish species have similar metal requirements, and because biological factors also intervened. Finally, since the study deals with metals, assumptions concerning trophic transfer factors calculation may not be suitable since the metal burden originates not only from the prey but also from adsorption over the body

  20. Carbon and nitrogen stable isotopes and metal concentration in food webs from a mining-impacted coastal lagoon

    Energy Technology Data Exchange (ETDEWEB)

    Marin-Guirao, Lazaro [Departamento de Ecologia e Hidrologia, Facultad de Biologia, Universidad de Murcia, 30100-Murcia (Spain)], E-mail: lamarin@um.es; Lloret, Javier; Marin, Arnaldo [Departamento de Ecologia e Hidrologia, Facultad de Biologia, Universidad de Murcia, 30100-Murcia (Spain)

    2008-04-01

    Two food webs from the Mar Menor coastal lagoon, differing in the distance from the desert-stream through which mining wastes were discharged, were examined by reference to essential (Zn and Cu) and non-essential (Pb and Cd) metal concentrations and stable isotopes content (C and N). The partial extraction technique applied, which reflects the availability of metals to organisms after sediment ingestion, showed higher bioavailable metal concentrations in sediments from the station influenced by the mining discharges, in agreement with the higher metal concentrations observed in organisms, which in many cases exceeded the regulatory limits established in Spanish legislation concerning seafood. Spatial differences in essential metal concentrations in the fauna suggest that several organisms are exposed to metal levels above their regulation capacity. Differences in isotopic composition were found between both food webs, the wadi-influenced station showing higher {delta}{sup 15}N values and lower {delta}{sup 13}C levels, due to the discharge of urban waste waters and by the entrance of freshwater and allochthonous marsh plants. The linear-regressions between trophic levels (as indicated by {delta}{sup 15}N) and the metal content indicated that biomagnification does not occur. In the case of invertebrates, since the 'handle strategy' of the species and the physiological requirements of the organisms, among other factors, determine the final concentration of a specific element, no clear relationships between trophic level and the metal content are to be expected. For their part, fish communities did not show clear patterns in the case of any of the analyzed metals, probably because most fish species have similar metal requirements, and because biological factors also intervened. Finally, since the study deals with metals, assumptions concerning trophic transfer factors calculation may not be suitable since the metal burden originates not only from the prey but

  1. Stable carbon and nitrogen isotopic compositions of ambient aerosols collected from Okinawa Island in the western North Pacific Rim, an outflow region of Asian dusts and pollutants

    Science.gov (United States)

    Kunwar, Bhagawati; Kawamura, Kimitaka; Zhu, Chunmao

    2016-04-01

    Stable carbon (δ13C) and nitrogen (δ15N) isotope ratios were measured for total carbon (TC) and nitrogen (TN), respectively, in aerosol (TSP) samples collected at Cape Hedo, Okinawa, an outflow region of Asian pollutants, during 2009-2010. The averaged δ13C and δ15N ratios are -22.2‰ and +12.5‰, respectively. The δ13C values are similar in both spring (-22.5‰) and winter (-22.5‰), suggesting the similar sources and/or source regions. We found that δ13C from Okinawa aerosols are ca. 2‰ higher than those reported from Chinese megacities probably due to photochemical aging of organic aerosols. A strong correlation (r = 0.81) was found between nss-Ca and TSP, suggesting that springtime aerosols are influenced from Asian dusts. However, carbonates in the Asian dusts were titrated with acidic species such as sulfuric acid and oxalic acid during atmospheric transport although two samples suggested the presence of remaining carbonate. No correlations were found between δ13C and tracer compounds (levoglucosan, elemental carbon, oxalic acid, and Na+). During winter and spring, coal burning is significant source in China. Based on isotopic mass balance, contribution of coal burning origin particles to total aerosol carbon was estimated as ca. 97% in winter, which is probably associated with the high emissions in China. Contribution of NO3- to TN was on average 45% whereas that of NH4+ was 18%. These results suggest that vehicular exhaust is an important source of TN in Okinawa aerosols. Concentration of water-soluble organic nitrogen (WSON) is higher in summer, suggesting that WSON is more emitted from the ocean in warmer season whereas inorganic nitrogen is more emitted in winter and spring from pollution sources in the Asian continent.

  2. Calcification rate and the stable carbon, oxygen, and nitrogen isotopes in the skeleton, host tissue, and zooxanthellae of bleached and recovering Hawaiian corals

    Science.gov (United States)

    Rodrigues, Lisa J.; Grottoli, Andréa G.

    2006-06-01

    We tested the effectiveness of stable isotopes as recorders of physiological changes that occur during coral bleaching and recovery. Montipora capitata and Porites compressa fragments were bleached in outdoor tanks with seawater temperature raised to 30 °C (treatment corals) for one month. Additional fragments were maintained at 27 °C in separate tanks (control corals). After one month, (0 months recovery), buoyant weight was measured and a subset of fragments was frozen. Remaining fragments were returned to the reef for recovery. After 1.5, 4, and 8 months, fragments were collected, measured for buoyant weight, and frozen. Fragments were analyzed for stable carbon and oxygen isotopic compositions of the skeleton (δ 13C s; δ 18O s) and nitrogen and carbon isotopic compositions of the host tissue (δ 15N h; δ 13C h) and zooxanthellae (δ 15N z; δ 13C z). δ 13C s decreased immediately after bleaching in M. capitata, but not in P. compressa. δ 18O s of both species failed to record the warming event. During the remaining months of recovery, δ 13C s and δ 18O s were more enriched in treatment than control corals due to decreases in calcification and metabolic fractionation during that time. Increased δ 15N h of treatment P. compressa may be due to expelled zooxanthellae during bleaching and recovery. Increased δ 15N z at 1.5 months in treatment fragments of both species reflects the increased incorporation of dissolved inorganic nitrogen to facilitate mitotic cell division and/or chl a/cell recovery. Changes in δ 13C h and δ 13C z at 1.5 months in treatment M. capitata indicated a large increase in heterotrophically acquired carbon relative to photosynthetically fixed carbon. We experimentally show that isotopes in coral skeleton, host tissue and zooxanthellae can be used to verify physiological changes during bleaching and recovery, but their use as a proxy for past bleaching events in the skeletal record is limited.

  3. Stable Carbon Isotope Characterization of CO2 Loss in Acid Mine Drainage Impacted Stream Water: Observations from a Laboratory Experiment

    Science.gov (United States)

    Ali, H. N.; Atekwana, E. A.

    2007-05-01

    Water from an acid mine drainage spring, ground water from a mine tailings pile, stream water and tap water were acidified to simulate acid mine drainage (AMD) contamination. The objective was to determine how acidification of stream water by AMD affected DIC loss and carbon isotope fraction. Two 20 L HDP containers (reactors) containing samples from each source were left un-acidified and allowed to evolve under ambient conditions for several weeks in the laboratory and two others were acidified. Acidification was carried out progressively with sulfuric acid to pH <3. For acidified samples, one reactor was acidified open to the atmosphere and the other closed from contact with atmosphere and CO2(g) was collected under vacuum. The un-acidified samples did not show significant alkalinity and DIC loss, and the 13C of DIC was enriched with time. The acidified samples showed decrease in alkalinity and DIC and increase in the 13C of DIC and CO2(g) with progressive acidification. The enrichment of 13C of DIC for un-acidified samples was due to exchange with atmospheric CO2. On the other hand, the 13C enrichment in the acidified samples was due to fractionation during dehydration of HCO3- and diffusive loss of CO2(g) from the aqueous phase. The actual values measured depended on the amount of CO2 lost from the aqueous phase during acidification. Samples with greater CO2 loss (closed acidification) had greater 13C enrichment. Beyond the HCO3- titration end point, the δ13C of DIC and CO2(g) was similar and nearly constant. The result of this study suggests that AMD effects on DIC can be modeled as a first order kinetic reaction and the isotope enrichment modeled using Rayleigh distillation.

  4. Stable carbon and oxygen isotope ratios of annual rings of pinus radiata provide an integrative record of canopy gas exchange

    International Nuclear Information System (INIS)

    Barbour, M.M.; Farquhar, G.D.

    2000-01-01

    Full text: Seasonal variation in δ 13 C and δ 18 O of cellulose from annual rings of Pinus radiata growing at each of three sites in New Zealand was measured. The three sites differed in annual water balance, temperature, and vapour pressure deficit, and these differences were reflected in cellulose δ 13 C and δ 18 O. Specific events such as drought or heavy rain were recorded as peaks and troughs in enrichment. A canopy-level combined photosynthesis and conductance model was linked to a model of soil water content and δ 18 O of xylem water to allow daily prediction of δ 13 C and δ 18 O of cellulose. A photosynthesis-weighted average of δ 13 C and δ 18 O was calculated for each sampling period. Each sample represented between 3 and 30 days, depending on stem growth rate. The timing and amplitude of changes in δ 13 C were predicted accurately by the model, while general seasonal patterns and event related peaks in δ 18 O enrichment were well predicted. These results suggest that stable isotope ratios of cellulose from annual rings reflect the canopy response to interactions between site-specific and seasonal variation in climatic conditions and soil water availability

  5. Strong evidence for terrestrial support of zooplankton in small lakes based on stable isotopes of carbon, nitrogen, and hydrogen

    Science.gov (United States)

    Cole, J.J.; Carpenter, S.R.; Kitchell, J.; Pace, M.L.; Solomon, C.T.; Weidel, B.

    2011-01-01

    Cross-ecosystem subsidies to food webs can alter metabolic balances in the receiving (subsidized) system and free the food web, or particular consumers, from the energetic constraints of local primary production. Although cross-ecosystem subsidies between terrestrial and aquatic systems have been well recognized for benthic organisms in streams, rivers, and the littoral zones of lakes, terrestrial subsidies to pelagic consumers are more difficult to demonstrate and remain controversial. Here, we adopt a unique approach by using stable isotopes of H, C, and N to estimate terrestrial support to zooplankton in two contrasting lakes. Zooplankton (Holopedium, Daphnia, and Leptodiaptomus) are comprised of ???20-40% of organic material of terrestrial origin. These estimates are as high as, or higher than, prior measures obtained by experimentally manipulating the inorganic 13C content of these lakes to augment the small, natural contrast in 13C between terrestrial and algal photosynthesis. Our study gives credence to a growing literature, which we review here, suggesting that significant terrestrial support of pelagic crustaceans (zooplankton) is widespread.

  6. Application of nitrogen and carbon stable isotopes (δ(15N and δ(13C to quantify food chain length and trophic structure.

    Directory of Open Access Journals (Sweden)

    Matthew J Perkins

    Full Text Available Increasingly, stable isotope ratios of nitrogen (δ(15N and carbon (δ(13C are used to quantify trophic structure, though relatively few studies have tested accuracy of isotopic structural measures. For laboratory-raised and wild-collected plant-invertebrate food chains spanning four trophic levels we estimated nitrogen range (NR using δ(15N, and carbon range (CR using δ(13C, which are used to quantify food chain length and breadth of trophic resources respectively. Across a range of known food chain lengths we examined how NR and CR changed within and between food chains. Our isotopic estimates of structure are robust because they were calculated using resampling procedures that propagate variance in sample means through to quantified uncertainty in final estimates. To identify origins of uncertainty in estimates of NR and CR, we additionally examined variation in discrimination (which is change in δ(15N or δ(13C from source to consumer between trophic levels and among food chains. δ(15N discrimination showed significant enrichment, while variation in enrichment was species and system specific, ranged broadly (1.4‰ to 3.3‰, and importantly, propagated variation to subsequent estimates of NR. However, NR proved robust to such variation and distinguished food chain length well, though some overlap between longer food chains infers a need for awareness of such limitations. δ(13C discrimination was inconsistent; generally no change or small significant enrichment was observed. Consequently, estimates of CR changed little with increasing food chain length, showing the potential utility of δ(13C as a tracer of energy pathways. This study serves as a robust test of isotopic quantification of food chain structure, and given global estimates of aquatic food chains approximate four trophic levels while many food chains include invertebrates, our use of four trophic level plant-invertebrate food chains makes our findings relevant for a majority

  7. Application of Nitrogen and Carbon Stable Isotopes (δ15N and δ13C) to Quantify Food Chain Length and Trophic Structure

    Science.gov (United States)

    Perkins, Matthew J.; McDonald, Robbie A.; van Veen, F. J. Frank; Kelly, Simon D.; Rees, Gareth; Bearhop, Stuart

    2014-01-01

    Increasingly, stable isotope ratios of nitrogen (δ15N) and carbon (δ13C) are used to quantify trophic structure, though relatively few studies have tested accuracy of isotopic structural measures. For laboratory-raised and wild-collected plant-invertebrate food chains spanning four trophic levels we estimated nitrogen range (NR) using δ15N, and carbon range (CR) using δ13C, which are used to quantify food chain length and breadth of trophic resources respectively. Across a range of known food chain lengths we examined how NR and CR changed within and between food chains. Our isotopic estimates of structure are robust because they were calculated using resampling procedures that propagate variance in sample means through to quantified uncertainty in final estimates. To identify origins of uncertainty in estimates of NR and CR, we additionally examined variation in discrimination (which is change in δ15N or δ13C from source to consumer) between trophic levels and among food chains. δ15N discrimination showed significant enrichment, while variation in enrichment was species and system specific, ranged broadly (1.4‰ to 3.3‰), and importantly, propagated variation to subsequent estimates of NR. However, NR proved robust to such variation and distinguished food chain length well, though some overlap between longer food chains infers a need for awareness of such limitations. δ13C discrimination was inconsistent; generally no change or small significant enrichment was observed. Consequently, estimates of CR changed little with increasing food chain length, showing the potential utility of δ13C as a tracer of energy pathways. This study serves as a robust test of isotopic quantification of food chain structure, and given global estimates of aquatic food chains approximate four trophic levels while many food chains include invertebrates, our use of four trophic level plant-invertebrate food chains makes our findings relevant for a majority of ecological systems

  8. Application of nitrogen and carbon stable isotopes (δ(15)N and δ(13)C) to quantify food chain length and trophic structure.

    Science.gov (United States)

    Perkins, Matthew J; McDonald, Robbie A; van Veen, F J Frank; Kelly, Simon D; Rees, Gareth; Bearhop, Stuart

    2014-01-01

    Increasingly, stable isotope ratios of nitrogen (δ(15)N) and carbon (δ(13)C) are used to quantify trophic structure, though relatively few studies have tested accuracy of isotopic structural measures. For laboratory-raised and wild-collected plant-invertebrate food chains spanning four trophic levels we estimated nitrogen range (NR) using δ(15)N, and carbon range (CR) using δ(13)C, which are used to quantify food chain length and breadth of trophic resources respectively. Across a range of known food chain lengths we examined how NR and CR changed within and between food chains. Our isotopic estimates of structure are robust because they were calculated using resampling procedures that propagate variance in sample means through to quantified uncertainty in final estimates. To identify origins of uncertainty in estimates of NR and CR, we additionally examined variation in discrimination (which is change in δ(15)N or δ(13)C from source to consumer) between trophic levels and among food chains. δ(15)N discrimination showed significant enrichment, while variation in enrichment was species and system specific, ranged broadly (1.4‰ to 3.3‰), and importantly, propagated variation to subsequent estimates of NR. However, NR proved robust to such variation and distinguished food chain length well, though some overlap between longer food chains infers a need for awareness of such limitations. δ(13)C discrimination was inconsistent; generally no change or small significant enrichment was observed. Consequently, estimates of CR changed little with increasing food chain length, showing the potential utility of δ(13)C as a tracer of energy pathways. This study serves as a robust test of isotopic quantification of food chain structure, and given global estimates of aquatic food chains approximate four trophic levels while many food chains include invertebrates, our use of four trophic level plant-invertebrate food chains makes our findings relevant for a majority of

  9. Combining Old and New Stable Isotope Techniques to Evaluate the Impact of Conservation Tillage on Soil Organic Carbon Dynamics and Stability

    International Nuclear Information System (INIS)

    De Clercq, T.; Xu, H.; Mercklx, R.; Heiling, M.; Dercon, G.; Resch, C.

    2016-01-01

    Soil organic matter (SOM) is a major carbon pool. It is a crucial factor for soil quality including several soil physical properties and a major nutrient source for crops. It also plays a significant role in the global carbon cycle. Soils can act as a carbon sink or source depending on land use and agricultural management practices. Some practices such as conservation tillage or no-tillage could increase SOM stocks, particularly in the topsoil, but in the long term it remains to be seen if and how this SOM is stabilized (De Clercq et al., 2015; Govaerts et al., 2009). In order to evaluate the sustainability and efficiency of soil carbon sequestration measures and the impact of different management and environmental factors, information on SOM stability and mean residence time (MRT) is required. However, this information on SOM stability and MRT is expensive to determine via radiocarbon dating, precluding a wide spread use of stability measurements in soil science. But alternative methods based on stable carbon and nitrogen isotopes, can provide this information at a fraction of the cost

  10. Summer precipitation influences the stable oxygen and carbon isotopic composition of tree-ring cellulose in Pinus ponderosa.

    Science.gov (United States)

    Roden, John S; Ehleringer, James R

    2007-04-01

    The carbon and oxygen isotopic composition of tree-ring cellulose was examined in ponderosa pine (Pinus ponderosa Dougl.) trees in the western USA to study seasonal patterns of precipitation inputs. Two sites (California and Oregon) had minimal summer rainfall inputs, whereas a third site (Arizona) received as much as 70% of its annual precipitation during the summer months (North American monsoon). For the Arizona site, both the delta(18)O and delta(13)C values of latewood cellulose increased as the fraction of annual precipitation occurring in the summer (July through September) increased. There were no trends in latewood cellulose delta(18)O with the absolute amount of summer rain at any site. The delta(13)C composition of latewood cellulose declined with increasing total water year precipitation for all sites. Years with below-average total precipitation tended to have a higher proportion of their annual water inputs during the summer months. Relative humidity was negatively correlated with latewood cellulose delta(13)C at all sites. Trees at the Arizona site produced latewood cellulose that was significantly more enriched in (18)O compared with trees at the Oregon or California site, implying a greater reliance on an (18)O-enriched water source. Thus, tree-ring records of cellulose delta(18)O and delta(13)C may provide useful proxy information about seasonal precipitation inputs and the variability and intensity of the North American monsoon.

  11. Diet and habitat of the saiga antelope during the late Quaternary using stable carbon and nitrogen isotope ratios

    Science.gov (United States)

    Jürgensen, Jonathan; Drucker, Dorothée G.; Stuart, Anthony J.; Schneider, Matthias; Buuveibaatar, Bayarbaatar; Bocherens, Hervé

    2017-03-01

    Saiga antelope (Saiga tatarica) is one of the typical late Pleistocene species of the cold and arid mammoth steppe that covered a large area of northern hemisphere. The species is currently endangered and persists only in small areas of Central Asian steppe and desert ecosystems. The investigation of the ecology of the Pleistocene saiga using stable isotope ratios (δ13C, δ15N) aimed to decipher how different their diet and habitat were from those observed nowadays in relict populations. Up to 76 samples of bone collagen of ancient saiga from Western Europe, Siberia and Eastern Beringia were analysed and compared with 52 samples of hair and bone collagen of modern specimens from Kazahkstan, Russia and Mongolia. The δ13C values of the ancient saiga do not exhibit a clear trend over time. They cover the same range of values as the modern ones, from a C3-dominated to a C3-C4-dominated mixed diet (including probably Chenopodiaceae). In contrast, the δ15N values of fossil saigas are more variable and lower on average than the extant ones. The lowest δ15N values of ancient saiga are found around the Last Glacial Maximum, reflecting the influence of the cold conditions at that time. On the other hand, fossil saiga occupying the same regions as the historical and modern populations exhibit high δ15N values similar to the modern ones, confirming ecological continuity over time. Modern saiga is thus occupying just one of its potential diverse habitats they used in the past. Therefore, the extant saiga is not a refugee species confined to a suboptimal habitat. During the late Pleistocene, the saiga occupied a separate niche compared with the other ungulates of the mammoth steppe. However, this species could also adapt to a lichen-dominated diet normally seen in reindeer, leading to an isotopic overlap between the two species in south-western France and Alaska around the Last Glacial Maximum. This adaptation allowed a geographical expansion that does not correspond to a

  12. Culture of microalgae Spirulina platensis with isotope stable Carbon-13; Cultivo da microalga Spirulina platensis com isótopo estável Carbono-13

    Energy Technology Data Exchange (ETDEWEB)

    Cronemberger, Luiz C.A.; Costa, Vladimir E., E-mail: luiz_cnst@hotmail.com, E-mail: vladimir@ibb.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (CIE/UNESP), Botucatu, SP (Brazil). Centro de Isótopos Estáveis Prof. Dr. Carlos Ducatti

    2017-07-01

    Gastric emptying time abnormalities cause complications that affect the quality of life in humans and scintigraphy is the gold standard for this diagnosis. However its application has restrictions due to the use of the radiopharmaceutical {sup 99m}Tc. An alternative to this method is the stable carbon isotope respiratory test. This is a non-radioactive, noninvasive technique with no contraindications. Its application varies according to the substrate used. For evaluation of gastric emptying time one of the substrates that can be used in the respiratory test is Spirulina platensis labeled at 97% carbon atoms with the stable isotope carbon-13 ({sup 13}C). In Brazil, there is no production of this substrate and its high cost (US$475.00/g, excluding import taxes) makes it difficult to apply the test. Thus, the objective of the work is to cultivate labeled S. platensis at 97% of {sup 13}C for use in the respiratory test for gastric emptying and to establish optimization parameters for the best cost-benefit of this culture. In the cultivation process the microalgae will be kept in a closed sterilized glass volumetric flask, with deionized water and a pure {sup 13}C source. The light (photoperiod 12h light / dark), pH (∼ 9.5) and temperature (30 deg C) will be controlled and after 35-40 days of growth, the cyanobacteria will be lyophilized and ground for the acquisition of a powder that will be analyzed by IRMS and compared to S. platensis, which will be our reference standard.

  13. Stable Carbon Isotope Fractionation during Bacterial Acetylene Fermentation: Potential for Life Detection in Hydrocarbon-Rich Volatiles of Icy Planet(oid)s.

    Science.gov (United States)

    Miller, Laurence G; Baesman, Shaun M; Oremland, Ronald S

    2015-11-01

    We report the first study of stable carbon isotope fractionation during microbial fermentation of acetylene (C2H2) in sediments, sediment enrichments, and bacterial cultures. Kinetic isotope effects (KIEs) averaged 3.7 ± 0.5‰ for slurries prepared with sediment collected at an intertidal mudflat in San Francisco Bay and 2.7 ± 0.2‰ for a pure culture of Pelobacter sp. isolated from these sediments. A similar KIE of 1.8 ± 0.7‰ was obtained for methanogenic enrichments derived from sediment collected at freshwater Searsville Lake, California. However, C2H2 uptake by a highly enriched mixed culture (strain SV7) obtained from Searsville Lake sediments resulted in a larger KIE of 9.0 ± 0.7‰. These are modest KIEs when compared with fractionation observed during oxidation of C1 compounds such as methane and methyl halides but are comparable to results obtained with other C2 compounds. These observations may be useful in distinguishing biologically active processes operating at distant locales in the Solar System where C2H2 is present. These locales include the surface of Saturn's largest moon Titan and the vaporous water- and hydrocarbon-rich jets emanating from Enceladus. Acetylene-Fermentation-Isotope fractionation-Enceladus-Life detection.

  14. Stable Isotope Signatures of Carbon and Nitrogen to Characterize Exchange Processes and Their Use for Restoration Projects along the Austrian Danube

    Energy Technology Data Exchange (ETDEWEB)

    Hein, T. [Wasser Cluster Lunz, Lunz-See and Institute of Hydrobiology and Aquatic Ecosystem Management, University for Natural Resources and Life Sciences, Vienna, (Austria); Bondar-Kunze, E. [University of Natural Resources and Applied Life Sciences, Vienna (Austria); Welti, N. [Institute of Hydrobiology and Aquatic Ecosystem Management, Vienna (Austria)

    2013-05-15

    The size and composition of an organic matter pool and its sources is a fundamental ecosystem property of river networks. River ecosystems are known to receive large amounts of terrestrial organic matter from catchments, still the question is to what extent aquatic sources influence riverine food webs or at least some components of these food webs. To identify different sources and their potential biological availability at the ecosystem level, we propose using stable isotope signatures of carbon and nitrogen and their respective elemental ratios. In this study, we used these parameters to evaluate river restoration measures. The target of the restoration was to improve surface connectivity between the main channel of the Danube downstream from Vienna and a side arm system within a floodplain. Analyses of the natural abundance of stable isotopes revealed that the restored side arm system showed distinct differences in the particulate organic matter pool in relation to hydrological connectivity. At low water levels, aquatic sources dominate in the side arm system, while at high water levels riverine organic matter is the dominating source. At medium connectivity levels aquatic sources also prevail in the side arm, thus an export of bio-available organic matter into the main channel can be expected. Based on these measurements, the increased - but hydrologically controlled - phytoplankton production was assessed and through this information, changes in ecosystem function were evaluated. (author)

  15. Pedogenic carbonate stable isotopic evidence for wooded habitat preference of early Pleistocene tool makers in the Turkana Basin.

    Science.gov (United States)

    Quinn, Rhonda L; Lepre, Christopher J; Feibel, Craig S; Wright, James D; Mortlock, Richard A; Harmand, Sonia; Brugal, Jean-Philip; Roche, Hélène

    2013-07-01

    The origin and evolution of early Pleistocene hominin lithic technologies in Africa occurred within the context of savanna grassland ecosystems. The Nachukui Formation of the Turkana Basin in northern Kenya, containing Oldowan and Acheulean tool assemblages and fossil evidence for early members of Homo and Paranthropus, provides an extensive spatial and temporal paleosol record of early Pleistocene savanna flora. Here we present new carbon isotopic (δ(13)CVPDB) values of pedogenic carbonates (68 nodules, 193 analyses) from the Nachukui Formation in order to characterize past vegetation structure and change through time. We compared three members (Kalochoro, Kaitio, and Natoo) at five locations spanning 2.4-1.4Ma and sampled in proximity to hominin archaeological and paleontological sites. Our results indicate diverse habitats showing a mosaic pattern of vegetation cover at each location yet demonstrate grassland expansion through time influenced by paleogeography. Kalochoro floodplains occurred adjacent to large river systems, and paleosols show evidence of C3 woodlands averaging 46-50% woody cover. Kaitio habitats were located along smaller rivers and lake margins. Paleosols yielded evidence for reduced portions of woody vegetation averaging 34-37% woody cover. Natoo environments had the highest percentage of grasslands averaging 21% woody cover near a diminishing Lake Turkana precursor. We also compared paleosol δ(13)CVPDB values of lithic archaeological sites with paleosol δ(13)CVPDB values of all environments available to hominins at 2.4-1.4Ma in the Nachukui and Koobi Fora Formations. Grassy environments became more widespread during this interval; woody canopy cover mean percentages steadily decreased by 12%. However, significantly more wooded savanna habitats were present in the vicinity of lithic archaeological sites and did not mirror the basin-wide trend of grassland spread. Hominin lithic archaeological sites consistently demonstrated woody cover

  16. In-situ studies of microbial CH{sub 4} oxidation efficiency in Arctic wetland soils. Applications of stable carbon isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Preuss, Inken-Marie

    2013-07-05

    Arctic wetland soils are significant sources of the climate-relevant trace gas methane (CH{sub 4}). The observed accelerated warming of the Arctic is expected to cause deeper permafrost thawing followed by increased carbon mineralization and CH{sub 4} formation in water-saturated permafrost-affected tundra soils thus creating a positive feedback to climate change. Aerobic CH{sub 4} oxidation is regarded as the key process reducing CH{sub 4} emissions from wetlands, but quantification of turnover rates has remained difficult so far. This study improved the in-situ quantification of microbial CH{sub 4} oxidation efficiency in arctic wetland soils in Russia's Lena River Delta based on stable isotope signatures of CH{sub 4}. In addition to the common practice of determining the stable isotope fractionation during oxidation, additionally the fractionation effect of diffusion, an important gas transport mechanism in tundra soils, was investigated for both saturated and unsaturated conditions. The isotopic fractionation factors α{sub ox} and α{sub diff} were used to calculate the CH{sub 4} oxidation efficiency from the CH{sub 4} stable isotope signatures of wet polygonal tundra soils of different hydrology. Further, the method was used to study the short-term effects of temperature increase with a climate manipulation experiment. For the first time, the stable isotope fractionation of CH{sub 4} diffusion through water-saturated soils was determined with α{sub diff} = 1.001 ± 0.0002 (n = 3). CH{sub 4} stable isotope fractionation during diffusion through air-filled pores of the investigated polygonal tundra soils was α{sub diff} = 1.013 ± 0.003 (n = 18). For the studied sites the fractionation factor for diffusion under saturated conditions α{sub diff} = 1.001 seems to be of utmost importance for the quantification of the CH{sub 4} oxidation efficiency, since most of the CH{sub 4} is oxidized in the saturated part at the aerobic-anaerobic interface. Furthermore

  17. Sediment source detection by stable isotope analysis, carbon and nitrogen content and CSSI in a small river of the Swiss Plateau

    Science.gov (United States)

    SchindlerWildhaber, Yael; Alewell, Christine; Birkholz, Axel

    2014-05-01

    Suspended sediment (SS) and organic matter in rivers can harm the fauna by affecting health and fitness of free swimming fish and by causing siltation of the riverbed. The temporal and spatial dynamics of sediment, carbon (C) and nitrogen (N) during the brown trout spawning season in a small river of the Swiss Plateau were assessed and C isotopes as well as the C/N atomic ratio were used to distinguish autochthonous and allochthonous sources of organic matter in SS loads. The visual basic program IsoSource with 13Ctot and 15N as input isotopes was used to quantify the temporal and spatial sources of SS. We determined compound specific stable carbon isotopes (CSSI) in fatty acids of possible sediment source areas to the stream in addition and compared them to SS from selected high flow and low flow events. Organic matter concentrations in the infiltrated and suspended sediment were highest during low flow periods with small sediment loads and lowest during high flow periods with high sediment loads. Peak values in nitrate and dissolved organic C were measured during high flow and high rainfall, probably due to leaching from pasture and arable land. The organic matter was of allochthonous sources as indicated by the C/N atomic ratio and δ13Corg. Organic matter in SS increased from up- to downstream due to an increase in sediment delivery from pasture and arable land downstream of the river. While the major sources of SS are pasture and arable land during base flow conditions, SS from forest soils increased during heavy rain events and warmer winter periods most likely due to snow melt which triggered erosion. Preliminary results of CSSI analysis of sediment source areas and comparison to SS of selected events indicate that differences in d13C values of individual fatty acids are too small to differentiate unambiguously between sediment sources.

  18. Metabolic studies in man using stable isotopes

    International Nuclear Information System (INIS)

    Faust, H.; Jung, K.; Krumbiegel, P.

    1993-01-01

    In this project, stable isotope compounds and stable isotope pharmaceuticals were used (with emphasis on the application of 15 N) to study several aspects of nitrogen metabolism in man. Of the many methods available, the 15 N stable isotope tracer technique holds a special position because the methodology for application and nitrogen isotope analysis is proven and reliable. Valid routine methods using 15 N analysis by emission spectrometry have been demonstrated. Several methods for the preparation of biological material were developed during our participation in the Coordinated Research Programme. In these studies, direct procedures (i.e. use of diluted urine as a samples without chemical preparation) or rapid isolation methods were favoured. Within the scope of the Analytical Quality Control Service (AQCS) enriched stable isotope reference materials for medical and biological studies were prepared and are now available through the International Atomic Energy Agency. The materials are of special importance as the increasing application of stable isotopes as tracers in medical, biological and agricultural studies has focused interest on reliable measurements of biological material of different origin. 24 refs

  19. Chemical characterization and stable carbon isotopic composition of particulate Polycyclic Aromatic Hydrocarbons issued from combustion of 10 Mediterranean woods

    Directory of Open Access Journals (Sweden)

    A. Guillon

    2013-03-01

    Full Text Available The objectives of this study were to characterize polycyclic aromatic hydrocarbons from particulate matter emitted during wood combustion and to determine, for the first time, the isotopic signature of PAHs from nine wood species and Moroccan coal from the Mediterranean Basin. In order to differentiate sources of particulate-PAHs, molecular and isotopic measurements of PAHs were performed on the set of wood samples for a large panel of compounds. Molecular profiles and diagnostic ratios were measured by gas chromatography/mass spectrometry (GC/MS and molecular isotopic compositions (δ13C of particulate-PAHs were determined by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS. Wood species present similar molecular profiles with benz(aanthracene and chrysene as dominant PAHs, whereas levels of concentrations range from 1.8 to 11.4 mg g−1 OC (sum of PAHs. Diagnostic ratios are consistent with reference ratios from literature but are not sufficient to differentiate the species of woods. Concerning isotopic methodology, PAH molecular isotopic compositions are specific for each species and contrary to molecular fingerprints, significant variations of δ13C are observed for the panel of PAHs. This work allows differentiating wood combustion (with δ13CPAH = −28.7 to −26.6‰ from others origins of particulate matter (like vehicular exhaust using isotopic measurements but also confirms the necessity to investigate source characterisation at the emission in order to help and complete source assessment models. These first results on woodburnings will be useful for the isotopic approach to source tracking.

  20. Effect of varying frontal systems on stable oxygen and carbon isotopic compositions of modern planktic foraminifera of Southern Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Tiwari, M.; Mohan, R.; Meloth, T.; Naik, S.S.; Sudhakar, M.

    , sediment cores and other physi- cal oceanographic parameters were collected. Here, we present the isotopic results obtained from planktic foraminifera from the plankton net samples and sur- face sediments. We find that, in this region too, plank- tic... characteristics in the Indian sector of the Southern Ocean. The δ 18 O value of planktic foraminifera is mainly governed by SST fluctuations: the samples be- come isotopically heavier polewards. Further, the plank- tic foraminifera appear to secrete...

  1. Dissolved organic carbon, CO2, and CH4 concentrations and their stable isotope ratios in thermokarst lakes on the Qinghai-Tibetan Plateau

    Directory of Open Access Journals (Sweden)

    Cuicui Mu

    2016-01-01

    Full Text Available Thermokarst lakes are widely distributed on the Qinghai-Tibetan Plateau (QTP, which accounts for 8% of the global permafrost area. These lakes probably promote organic matter biodegradation and thus accelerate the emission of carbon-based greenhouse gases. However, little is known about greenhouse gas concentrations and their stable isotopes characteristics of these lakes. In this study, we measured the concentrations of dissolved organic carbon (DOC, dissolved CO2 and CH4, as well as the distribution of δ13CCO2, δ13CCH4, and δ13COM (organic matter of lake sediments in thermokarst lakes on the QTP. Results showed that the OM of the lake sediments was highly decomposed. The concentrations of DOC, CO2 and CH4 in the lake water on the QTP were 1.2–49.6 mg L–1, 3.6–45.0 μmol L–1 and 0.28–3.0 μmol L–1, respectively. The highest CO2 and CH4 concentrations were recorded in July while the lowest values in September, which suggested that temperature had an effect on greenhouse gas production, although this pattern may also relate to thermal stratification of the water column. The results implied that thermokast lakes should be paid more attention to regarding carbon cycle and greenhouse gas emissions on the QTP.

  2. Characteristics and carbon stable isotopes of fluids in the Southern Kerala granulites and their bearing on the source of CO2

    Science.gov (United States)

    Santosh, M.; Jackson, D. H.; Mattey, D. P.; Harris, N. B. W.

    1988-01-01

    Carbon dioxide-rich inclusions commonly occur in the banded charnockites and khondalites of southern Kerala as well as in the incipient charnockites formed by desiccation of gneisses along oriented zones. The combined high density fluid inclusion isochores and the range of thermometric estimates from mineral assemblages indicate entrapment pressures in the range of 5.4 to 6.1 Kbar. The CO2 equation of state barometry closely compares with the 5 plus or minus 1 Kbar estimate from mineral phases for the region. The isochores for the high density fluid inclusions in all the three rock types pass through the P-T domain recorded by phase equilibria, implying that carbon dioxide was the dominating ambient fluid species during peak metamorphic conditions. In order to constrain the source of fluids and to evaluate the mechanism of desiccation, researchers undertook detailed investigations of the carbon stable isotope composition of entrapped fluids. Researchers report here the results of preliminary studies in some of the classic localities in southern Kerala namely, Ponmudi, Kottavattom, Manali and Kadakamon.

  3. Stable carbon isotopic compositions of low-molecular-weight dicarboxylic acids, glyoxylic acid and glyoxal in tropical aerosols: implications for photochemical processes of organic aerosols

    Directory of Open Access Journals (Sweden)

    Stelyus L. Mkoma

    2014-10-01

    Full Text Available Tropical aerosols of PM2.5 and PM10 were collected at a rural site in Morogoro, Tanzania (East Africa, and analysed for stable carbon isotopic composition (δ13C of dicarboxylic acids (C2–C9, glyoxylic acid (ωC2 and glyoxal (Gly using gas chromatography/isotope ratio mass spectrometer. PM2.5 samples showed that δ13C of oxalic (C2 acid are largest (mean, −18.3±1.7‰ followed by malonic (C3, −19.6±1.0‰ and succinic (C4, −21.8±2.2‰ acids, whereas those in PM10 are a little smaller: −19.9±3.1‰ (C2, −20.2±2.7‰ (C3 and −23.3±3.2‰ (C4. The δ13C of C2–C4 diacids showed a decreasing trend with an increase in carbon numbers. The higher δ13C values of oxalic acid can be explained by isotopic enrichment of 13C in the remaining C2 due to the atmospheric decomposition of oxalic acid or its precursors. δ13C of ωC2 and Gly that are precursors of oxalic acid also showed larger values (mean, −22.5‰ and −20.2‰, respectively in PM2.5 than those (−26.7‰ and −23.7‰ in PM10. The δ13C values of ωC2 and Gly are smaller than those of C2 in both PM2.5 and PM10. On the other hand, azelaic acid (C9; mean, −28.5‰ is more depleted in 13C, which is consistent with the previous knowledge; that is, C9 is produced by the oxidation of unsaturated fatty acids emitted from terrestrial higher plants. A significant enrichment of 13C in oxalic acid together with its negative correlations with relative abundance of C2 in total diacids and ratios of water-soluble organic carbon and organic carbon further support that a photochemical degradation of oxalic acid occurs during long-range transport from source regions.

  4. Stable Oxygen-18 and Deuterium Isotopes

    DEFF Research Database (Denmark)

    Müller, Sascha

    The application of stable Oxygen-18 (18O) and Deuterium (2H) isotopes, as a tracer for fluxes between different compartments of the water cycle was subject of the present PhD-thesis. During a three year period, temporal data from a wide range of water cycle constituents was collected from...... the Skjern River catchment, Denmark. The presented applications focused on studying the isotopic 'input signal' to the hydrosphere in the form of precipitation, the isotopic 'output signal' with its related dynamic processes at a coastal saltwater-freshwater interface (groundwater isotopes) and the temporal...... development within a given lowland headwater catchment (stream water isotopes). Based on our investigations on the precipitation isotopic composition a local meteoric water line (LMWL) was constructed and expressed as: δ2H=7.4 δ18O + 5.36‰. Moreover, we showed that under maritime temperature climate influence...

  5. Applications of C and N stable isotopes to ecological and environmental studies in seagrass ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Lepoint, Gilles [Centre MARE, Laboratoire d' Oceanologie, Institut de Chimie, B6, Universite de Liege, B-4000 Liege (Belgium)]. E-mail: g.lepoint@ulg.ac.be; Dauby, Patrick [Centre MARE, Laboratoire d' Oceanologie, Institut de Chimie, B6, Universite de Liege, B-4000 Liege (Belgium); Institut Royal des Sciences Naturelles de Belgique, rue Vautier, B1000 Brussels (Belgium); Gobert, Sylvie [Centre MARE, Laboratoire d' Oceanologie, Institut de Chimie, B6, Universite de Liege, B-4000 Liege (Belgium)

    2004-12-01

    Stable isotopes of carbon and nitrogen are increasingly used in marine ecosystems, for ecological and environmental studies. Here, we examine some applications of stable isotopes as ecological integrators or tracers in seagrass ecosystem studies. We focus on both the use of natural isotope abundance as food web integrators or environmental tracers and on the use of stable isotopes as experimental tools. As ecosystem integrators, stable isotopes have helped to elucidate the general structure of trophic webs in temperate, Mediterranean and tropical seagrass ecosystems. As environmental tracers, stable isotopes have proven their utility in sewage impact measuring and mapping. However, to make such environmental studies more comprehensible, future works on understanding of basic reasons for variations of N and C stable isotopes in seagrasses should be encouraged. At least, as experimental tracers, stable isotopes allow the study of many aspects of N and C cycles at the scale of a plant or at the scale of the seagrass ecosystem.

  6. Stable carbon isotope composition (δ{sup 13}C), water use efficiency, and biomass productivity of Lycopersicon esculentum, Lycopersicon pennellii, and the F{sub 1} hybrid

    Energy Technology Data Exchange (ETDEWEB)

    Martin, B.; Thorstenson, Y. R.

    1988-09-01

    Three tomatoes, Lycopersicon esculentum Mill. cv UC82B, a droughttolerant wild related species, Lycopersicon pennellii (Cor.) D'Arcy, and their F{sub 1}, hybrid, were grown in containers maintained at three levels of soil moisture. Season-long water use was obtained by summing over the season daily weight losses of each container corrected for soil evaporation. Plant biomass was determined by harvesting and weighing entire dried plants. Season-long water use efficiency (gram dry weight/kilogram H{sub 2}O) was calculated by dividing the dry biomass by the season-long water use. The season-long water use efficiency was greatest in the wild parent, poorest in the domestic parent, and intermediate (but closer to the wild parent) in the F, hybrid. Instantaneous water-use efficiency (micromole CO{sub 2}/millimole H{sub 2}O) determined by gas exchange measurements on individual leaves was poorly correlated with season-long water use efficiency. However, the relative abundance of stable carbon isotopes of leaf tissue samples was strongly correlated with the season-long water use efficiency. Also, the isotopic composition and the season-long water use efficiency of each genotype alone were strongly negatively correlated with plant dry weight when the dry weight varied as a function of soil moisture. (author)

  7. Stable carbon isotope variability of bone collagen and hair within a modern population of red kangaroos (Macropus rufus) in south western Queensland: some implications for palaeoecological research

    International Nuclear Information System (INIS)

    Witt, G.B.

    1997-01-01

    Full text: Before any palaeo-reconstruction work can be attempted using stable isotope analysis of macropod remains it will be necessary to determine the nature of natural variability within contemporary populations. This research indicates that δ 13 C of bone collagen is strongly related to age. Furthermore, bone collagen δ 13 C not at equilibrium with dietary δ 13 C, as indicated by analysis of hair, until animals are several years old. These preliminary data suggest that in younger macropods most carbon in bone collagen has been derived via the mother's milk which may have undergone fractionation. These findings have significant implications for any palaeoecological research using bone or tooth. Teeth of macropods erupt from the rear of the jaw and move forward in molar progression. Since the rate of eruption is variable, and many of the forward molars are well formed while the joey is still at the pouch, teeth formed early in the life of a macropod may be isotopically distinct from those that develop later. This hypothesis is currently under investigation

  8. 14C dating and stable carbon isotopes of soil organic matter in the Southeastern region of Sao Paulo State

    International Nuclear Information System (INIS)

    Mofatto, Milene; Pessenda, Luiz Carlos Ruiz; Bendassoli, Jose Albertino; Leite, Acacio Zuniga; Oliveira, Paulo de Oliveira; Garcia, Ricardo Jose Francischetti

    2005-01-01

    The objective of this research is to characterize the isotopic composition ( 13 C, 14 C) of soil organic matter (SOM) in the Parque Estadual da Serra do Mar-Nucleo Curucutu, Sao Paulo state, Southeastern Brazil. The isotopic composition (δ 13 C) of SOM will be used as an indicator of vegetation types from the local ecosystems and 14 C dating (humin fraction) used to determine the chronology. The results from SOM indicated vegetation changes in the last 10,000 years, where, a less dense vegetation occurred in the past, with C 3 plant predominant and/or a mixture of C 3 and C 4 . (author)

  9. Important considerations in the use of carbon and hydrogen stable isotopes to determine the origin of hydrocarbons in groundwater – A case study from pre-shale gas Tioga County

    Science.gov (United States)

    stable carbon and hydrogen isotopic compositional ranges of methanes (δ13C and δ2H (D)) enable us to distinguish between microbial and thermogenic origin of natural gases. To identify stray gas origins, identify possible gas sources, create baseline, carry out site-specific monitoring, and monitor long-term changes

  10. Application of Stable Isotope Signatures in Food Traceability

    International Nuclear Information System (INIS)

    Nazaratul Ashifa Abdullah Salim; Roslanzairi Mostapha; Zainon Othman

    2016-01-01

    Stable isotope analysis has widely been used to trace the origin of organic materials in various fields, such as geochemistry, biochemistry, archaeology and petroleum. In past a decade, it has also become an important tool for food traceability study. The globalisation of food markets and the relative ease which food commodities are transported through and between countries and continents means that consumers are increasingly concerned about the origin of the foods they eat. The natural abundance of stable isotope variation such as carbon, nitrogen, hydrogen and oxygen are used as geographic tracers or marker to determine the geographic origin of fruits, crop, vegetables and food products from animal. The isotopic compositions of plant materials reflect various factors such as isotopic compositions of source materials and their assimilation processes as well as growth environments. This paper will discuss on stable carbon and nitrogen isotopic compositions in rice that been determined by Isotope Ratio Mass Spectrometry, advantages, limitations and potential of other analysis applications that can be incorporated in food traceability system. (author)

  11. Tree-ring stable carbon isotope-based April-June relative humidity reconstruction since ad 1648 in Mt. Tianmu, China

    Science.gov (United States)

    Liu, Yu; Ta, Weiyuan; Li, Qiang; Song, Huiming; Sun, Changfeng; Cai, Qiufang; Liu, Han; Wang, Lu; Hu, Sile; Sun, Junyan; Zhang, Wenbiao; Li, Wenzhu

    2018-03-01

    Based on accurate dating, we have determined the stable carbon isotope ratios (δ13C) of five Cryptomeria fortunei specimens from Mt. Tianmu, a subtropical area in southern China. The five δ13C time series records are combined into a single representative δ13C time series using a "numerical mix method." These are normalized to remove temporal variations of δ13 C in atmospheric CO2 to obtain a carbon isotopic discrimination (Δ13C) time series, in which we observe a distinct correlation between Δ13C and local April to June mean relative humidity ( RH AMJ ) (n = 64, r = 0.858, p use this relationship to reconstruct RH AMJ variations from ad 1648 to 2014 at Mt. Tianmu. The reconstructed sequence show that over the past 367 years, Mt. Tianmu area was relatively wet, but in the latter part of the twentieth century, under the influence of increasing global warming, it has experienced a sharp reduction in relative humidity. Spatial correlation analysis reveals a significant negative correlation between RH AMJ at Mt. Tianmu and Sea Surface Temperature (SSTs) in the western equatorial Pacific and Indian Ocean. In other words, there is a positive correlation between tree-ring δ13C in Mt. Tianmu and SSTs. Both observed and reconstructed RH AMJ show significant positive correlations with East Asian and South Asian monsoons from 1951 to 2014, which indicate that RH AMJ from Mt. Tianmu reflects the variability of the Asian summer monsoon intensity to a great extent. The summer monsoon has weakened since 1960. However, an increase in relative humidity since 2003 implies a recent enhancement in the summer monsoon.

  12. Innovative method for carbon dioxide determination in human postmortem cardiac gas samples using headspace-gas chromatography–mass spectrometry and stable labeled isotope as internal standard

    International Nuclear Information System (INIS)

    Varlet, V.; Smith, F.; Froidmont, S. de; Dominguez, A.; Rinaldi, A.; Augsburger, M.; Mangin, P.; Grabherr, S.

    2013-01-01

    Graphical abstract: -- Highlights: •We developed a method for CO 2 analysis in cardiac samples and quantification by 13 CO 2 . •This method was fully validated by accuracy profile. •We have applied this method to perform CO 2 precise quantification for forensic applications. •Context of the death could be documented following CO 2 concentrations. -- Abstract: A novel approach to measure carbon dioxide (CO 2 ) in gaseous samples, based on a precise and accurate quantification by 13 CO 2 internal standard generated in situ is presented. The main goal of this study was to provide an innovative headspace-gas chromatography–mass spectrometry (HS-GC–MS) method applicable in the routine determination of CO 2 . The main drawback of the GC methods discussed in the literature for CO 2 measurement is the lack of a specific internal standard necessary to perform quantification. CO 2 measurement is still quantified by external calibration without taking into account analytical problems which can often occur considering gaseous samples. To avoid the manipulation of a stable isotope-labeled gas, we have chosen to generate in situ an internal labeled standard gas ( 13 CO 2 ) on the basis of the stoichiometric formation of CO 2 by the reaction of hydrochloric acid (HCl) with sodium hydrogen carbonate (NaH 13 CO 3 ). This method allows a precise measurement of CO 2 concentration and was validated on various human postmortem gas samples in order to study its efficiency

  13. Bimodality in stable isotope composition facilitates the tracing of carbon transfer from macrophytes to higher trophic levels

    NARCIS (Netherlands)

    Mendonca, R.; Kosten, S.; Lacerot, G.; Mazzeo, N.; Roland, F.; Ometto, J.P.; Paz, A.; Bueno, O.C.; Gomes, A.C.M.M.; Scheffer, M.

    2013-01-01

    Even though the suitability of macrophytes to act as a carbon source to food webs has been questioned by some studies, some others indicate that macrophyte-derived carbon may play an important role in the trophic transfer of organic matter in the food web of shallow lakes. To evaluate the importance

  14. Stable oxygen isotope and flux partitioning demonstrates understory of an oak savanna contributes up to half of ecosystem carbon and water exchange

    Directory of Open Access Journals (Sweden)

    Maren eDubbert

    2014-10-01

    Full Text Available Semi-arid ecosystems contribute about 40% to global net primary production (GPP even though water is a major factor limiting carbon uptake. Evapotranspiration (ET accounts for up to 95% of the water loss and in addition, vegetation can also mitigate drought effects by altering soil water distribution. Hence, partitioning of carbon and water fluxes between the soil and vegetation components is crucial to gain mechanistic understanding of vegetation effects on carbon and water cycling. However, the possible impact of herbaceous vegetation in savanna type ecosystems is often overlooked. Therefore, we aimed at quantifying understory vegetation effects on the water balance and productivity of a Mediterranean oak savanna. ET and net ecosystem CO2 exchange (NEE were partitioned based on flux and stable oxygen isotope measurements and also rain infiltration was estimated.The understory vegetation contributed importantly to total ecosystem ET and GPP with a maximum of 43% and 51%, respectively. It reached water-use efficiencies (WUE; ratio of carbon gain by water loss similar to cork-oak trees. The understory vegetation inhibited soil evaporation (E and, although E was large during wet periods, it did not diminish WUE during water-limited times. The understory strongly increased soil water infiltration, specifically following major rain events. At the same time, the understory itself was vulnerable to drought, which led to an earlier senescence of the understory growing under trees as compared to open areas, due to competition for water. Thus, beneficial understory effects are dominant and contribute to the resilience of this ecosystem. At the same time the vulnerability of the understory to drought suggests that future climate change scenarios for the Mediterranean basin threaten understory development. This in turn will very likely diminish beneficial understory effects like infiltration and ground water recharge and therefore ecosystem resilience to

  15. Online Stable Isotope Analysis of Dissolved Organic Carbon Size Classes Using Size Exclusion Chromatography Coupled to an Isotope Ratio Mass Spectrometer

    Digital Repository Service at National Institute of Oceanography (India)

    Malik, A.; Scheibe, A.; LokaBharathi, P.A.; Gleixner, G.

    size classes by coupling high-performance liquid chromatography (HPLC) - size exclusion chromatography (SEC) to online isotope ratio mass spectrometry (IRMS). This represents a significant methodological contribution to DOC research. The interface...

  16. Diurnal variations of organic molecular tracers and stable carbon isotopic composition in atmospheric aerosols over Mt. Tai in the North China Plain: an influence of biomass burning

    Directory of Open Access Journals (Sweden)

    P. Q. Fu

    2012-09-01

    Full Text Available Organic tracer compounds, as well as organic carbon (OC, elemental carbon (EC, water-soluble organic carbon (WSOC, and stable carbon isotope ratios (δ13C of total carbon (TC have been investigated in aerosol samples collected during early and late periods of the Mount Tai eXperiment 2006 (MTX2006 field campaign in the North China Plain. Total solvent-extractable fractions were investigated by gas chromatography/mass spectrometry. More than 130 organic compounds were detected in the aerosol samples. They were grouped into twelve organic compound classes, including biomass burning tracers, biogenic primary sugars, biogenic secondary organic aerosol (SOA tracers, and anthropogenic tracers such as phthalates, hopanes and polycyclic aromatic hydrocarbons (PAHs. In early June when the field burning activities of wheat straws in the North China Plain were very active, the total identified organics (2090 ± 1170 ng m−3 were double those in late June (926 ± 574 ng m−3. All the compound classes were more abundant in early June than in late June, except phthalate esters, which were higher in late June. Levoglucosan (88–1210 ng m−3, mean 403 ng m−3 was found as the most abundant single compound in early June, while diisobutyl phthalate was the predominant species in late June. During the biomass-burning period in early June, the diurnal trends of most of the primary and secondary organic aerosol tracers were characterized by the concentration peaks observed at mid-night or in early morning, while in late June most of the organic species peaked in late afternoon. This suggests that smoke plumes from biomass burning can uplift the aerosol particulate matter to a certain altitude, which could be further transported to and encountered the summit of Mt. Tai during nighttime. On the basis of the tracer-based method for the estimation of biomass-burning OC, fungal-spore OC and biogenic secondary

  17. Diurnal variations of organic molecular tracers and stable carbon isotopic composition in atmospheric aerosols over Mt. Tai in the North China Plain: an influence of biomass burning

    Science.gov (United States)

    Fu, P. Q.; Kawamura, K.; Chen, J.; Li, J.; Sun, Y. L.; Liu, Y.; Tachibana, E.; Aggarwal, S. G.; Okuzawa, K.; Tanimoto, H.; Kanaya, Y.; Wang, Z. F.

    2012-09-01

    Organic tracer compounds, as well as organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), and stable carbon isotope ratios (δ13C) of total carbon (TC) have been investigated in aerosol samples collected during early and late periods of the Mount Tai eXperiment 2006 (MTX2006) field campaign in the North China Plain. Total solvent-extractable fractions were investigated by gas chromatography/mass spectrometry. More than 130 organic compounds were detected in the aerosol samples. They were grouped into twelve organic compound classes, including biomass burning tracers, biogenic primary sugars, biogenic secondary organic aerosol (SOA) tracers, and anthropogenic tracers such as phthalates, hopanes and polycyclic aromatic hydrocarbons (PAHs). In early June when the field burning activities of wheat straws in the North China Plain were very active, the total identified organics (2090 ± 1170 ng m-3) were double those in late June (926 ± 574 ng m-3). All the compound classes were more abundant in early June than in late June, except phthalate esters, which were higher in late June. Levoglucosan (88-1210 ng m-3, mean 403 ng m-3) was found as the most abundant single compound in early June, while diisobutyl phthalate was the predominant species in late June. During the biomass-burning period in early June, the diurnal trends of most of the primary and secondary organic aerosol tracers were characterized by the concentration peaks observed at mid-night or in early morning, while in late June most of the organic species peaked in late afternoon. This suggests that smoke plumes from biomass burning can uplift the aerosol particulate matter to a certain altitude, which could be further transported to and encountered the summit of Mt. Tai during nighttime. On the basis of the tracer-based method for the estimation of biomass-burning OC, fungal-spore OC and biogenic secondary organic carbon (SOC), we estimate that an average of 24% (up to 64%) of the

  18. Diurnal variations of organic molecular tracers and stable carbon isotopic compositions in atmospheric aerosols over Mt. Tai in North China Plain: an influence of biomass burning

    Science.gov (United States)

    Fu, P. Q.; Kawamura, K.; Chen, J.; Li, J.; Sun, Y. L.; Liu, Y.; Tachibana, E.; Aggarwal, S. G.; Okuzawa, K.; Tanimoto, H.; Kanaya, Y.; Wang, Z. F.

    2012-04-01

    Organic tracer compounds of tropospheric aerosols, as well as organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), and stable carbon isotope ratios (δ13C) of total carbon (TC) have been investigated for aerosol samples collected during early and late periods of Mount Tai eXperiment 2006 (MTX2006) field campaign in North China Plain. Total solvent extracts were investigated by gas chromatography/mass spectrometry. More than 130 organic compounds were detected in the aerosol samples. They were grouped into twelve organic compound classes, including biomass burning tracers, biogenic primary sugars, biogenic secondary organic aerosol (SOA) tracers, and anthropogenic tracers such as phthalates, hopanes and polycyclic aromatic hydrocarbons (PAHs). In early June when the field burning activities of wheat straws in North China Plain were very active, the total identified organics (2090 ± 1170 ng m-3) were double those in late June (926 ± 574 ng m-3). All the compound classes were more abundant in early June than in late June, except phthalate esters, which were higher in late June. Levoglucosan (88-1210 ng m-3, 403 ng m-3) was found as the most abundant single compound in early June, while diisobutyl phthalate was the predominant species in late June. During the biomass-burning period in early June, the diurnal trends of most of the primary and secondary organic aerosol tracers were characterized by the concentration peaks observed at mid-night or in early morning, while in late June most of the organic species peaked in late afternoon. This suggests that smoke plumes from biomass burning can uplift the aerosol particulate matter to a certain altitude and then transported to and encountered the summit of Mt. Tai during nighttime. On the basis of the tracer-based method for the estimation of biomass-burning OC, fungal-spore OC and biogenic secondary organic carbon (SOC), we estimate that an average of 24% (up to 64%) of the OC in the Mt. Tai

  19. Stable isotope composition of human fingernails from Slovakia

    International Nuclear Information System (INIS)

    Grolmusová, Zuzana; Rapčanová, Anna; Michalko, Juraj; Čech, Peter; Veis, Pavel

    2014-01-01

    Stable isotope composition of human fingernails has proven to be useful for documenting human dietary information and geographical patterns in archeological, forensic, anthropological and biological studies. Therefore, it is of interest to detect all factors influencing the stable isotopic composition in the certain regions in the world. Carbon and nitrogen isotope data of human fingernail keratin from 52 individuals from Slovakia were reported in this study. The online combustion and continuous flow isotope-ratio mass spectrometer Delta V Advantage was used for δ 13 C and δ 15 N analysis of fingernail keratin samples from 24 vegetarian and 28 omnivorous individuals. A group of people with frequent meat consumption showed enrichment in 13 C and 15 N isotopes in fingernails. A similar trend was observed with increasing seafood in an individual's diet. Moreover a significant difference was revealed between smokers and nonsmokers for both δ 13 C and δ 15 N values. These data were compared to previously published δ 13 C and δ 15 N fingernail values from across the globe. This study brings new information on the stable isotope signature of individuals from Slovakia and characterizes the Central European region for the first time. The stable isotope composition of fingernails is influenced by the frequency of meat and seafood consumption as well as smoking. - Highlights: • This study deals with stable isotope analyses of fingernails from Slovak volunteers. • δ 13 C and δ 15 N values of vegetarian and omnivore fingernails were compared. • Influence of sex, diet and smoking was studied

  20. Stable isotope composition of human fingernails from Slovakia

    Energy Technology Data Exchange (ETDEWEB)

    Grolmusová, Zuzana, E-mail: zuzana.grolmusova@geology.sk [Comenius University in Bratislava, Faculty of Mathematics, Physics and Informatics, Department of Experimental Physics, Mlynská dolina F2, 842 48 Bratislava (Slovakia); State Geological Institute of Dionýz Štúr, Laboratory of Isotope Geology, Mlynská dolina 1, 817 04 Bratislava (Slovakia); Rapčanová, Anna [Comenius University in Bratislava, Faculty of Mathematics, Physics and Informatics, Department of Experimental Physics, Mlynská dolina F2, 842 48 Bratislava (Slovakia); Michalko, Juraj; Čech, Peter [State Geological Institute of Dionýz Štúr, Laboratory of Isotope Geology, Mlynská dolina 1, 817 04 Bratislava (Slovakia); Veis, Pavel [Comenius University in Bratislava, Faculty of Mathematics, Physics and Informatics, Department of Experimental Physics, Mlynská dolina F2, 842 48 Bratislava (Slovakia); State Geological Institute of Dionýz Štúr, Laboratory of Isotope Geology, Mlynská dolina 1, 817 04 Bratislava (Slovakia)

    2014-10-15

    Stable isotope composition of human fingernails has proven to be useful for documenting human dietary information and geographical patterns in archeological, forensic, anthropological and biological studies. Therefore, it is of interest to detect all factors influencing the stable isotopic composition in the certain regions in the world. Carbon and nitrogen isotope data of human fingernail keratin from 52 individuals from Slovakia were reported in this study. The online combustion and continuous flow isotope-ratio mass spectrometer Delta V Advantage was used for δ{sup 13}C and δ{sup 15}N analysis of fingernail keratin samples from 24 vegetarian and 28 omnivorous individuals. A group of people with frequent meat consumption showed enrichment in {sup 13}C and {sup 15}N isotopes in fingernails. A similar trend was observed with increasing seafood in an individual's diet. Moreover a significant difference was revealed between smokers and nonsmokers for both δ{sup 13}C and δ{sup 15}N values. These data were compared to previously published δ{sup 13}C and δ{sup 15}N fingernail values from across the globe. This study brings new information on the stable isotope signature of individuals from Slovakia and characterizes the Central European region for the first time. The stable isotope composition of fingernails is influenced by the frequency of meat and seafood consumption as well as smoking. - Highlights: • This study deals with stable isotope analyses of fingernails from Slovak volunteers. • δ{sup 13}C and δ{sup 15}N values of vegetarian and omnivore fingernails were compared. • Influence of sex, diet and smoking was studied.

  1. Stable carbon and hydrogen isotope analysis of methyl tert-butyl ether and tert-amyl methyl ether by purge and trap-gas chromatography-isotope ratio mass spectrometry: method evaluation and application.

    Science.gov (United States)

    Kujawinski, Dorothea M; Stephan, Manuel; Jochmann, Maik A; Krajenke, Karen; Haas, Joe; Schmidt, Torsten C

    2010-01-01

    In order to monitor the behaviour of contaminants in the aqueous environment effective enrichment techniques often have to be employed due to their low concentrations. In this work a robust and sensitive purge and trap-gas chromatography-isotope ratio mass spectrometry method for carbon and hydrogen isotope analysis of fuel oxygenates in water is presented. The method evaluation included the determination of method detection limits, accuracy and reproducibility of deltaD and delta(13)C values. Lowest concentrations at which reliable delta(13)C values could be determined were 5 microg L(-1) and 28 microg L(-1) for TAME and MTBE, respectively. Stable deltaD values for MTBE and TAME could be achieved for concentrations as low as 25 and 50 microg L(-1). Good long-term reproducibility of delta(13)C and deltaD values was obtained for all target compounds. But deltaD values varying more than 5 per thousand were observed using different thermal conversion tubes. Thus, a correction of deltaD values in the analysis of groundwater samples was necessary to guarantee comparability of the results. The applicability of this method was shown by the analysis of groundwater samples from a gasoline contaminated site. By two dimensional isotope analysis two locations within this site were identified at which anaerobic and aerobic degradation of methyl tert-butyl ether occurred.

  2. Molecular distribution and compound-specific stable carbon isotopic composition of dicarboxylic acids, oxocarboxylic acids and α-dicarbonyls in PM2.5 from Beijing, China

    Directory of Open Access Journals (Sweden)

    W. Zhao

    2018-02-01

    Full Text Available This study investigates the seasonal variation, molecular distribution and stable carbon isotopic composition of diacids, oxocarboxylic acids and α-dicarbonyls to better understand the sources and formation processes of fine aerosols (PM2.5 in Beijing. The concentrations of total dicarboxylic acids varied from 110 to 2580 ng m−3, whereas oxoacids (9.50–353 ng m−3 and dicarbonyls (1.50–85.9 ng m−3 were less abundant. Oxalic acid was found to be the most abundant individual species, followed by succinic acid or occasionally by terephthalic acid (tPh, a plastic waste burning tracer. Ambient concentrations of phthalic acid (37.9 ± 27.3 ng m−3 and tPh (48.7 ± 51.1 ng m−3 were larger in winter than in other seasons, illustrating that fossil fuel combustion and plastic waste incineration contribute more to wintertime aerosols. The year-round mass concentration ratios of malonic acid to succinic acid (C3 ∕ C4 were relatively low by comparison with those in other urban aerosols and remote marine aerosols. The values were less than or equal to unity in Beijing, implying that the degree of photochemical formation of diacids in Beijing is insignificant. Moreover, strong correlation coefficients of major oxocarboxylic acids and α-dicarbonyls with nss-K+ suggest that biomass burning contributes significantly to these organic acids and related precursors. The mean δ13C value of succinic acid is the highest among all species, with values of −17.1 ± 3.9 ‰ (winter and −17.1 ± 2.0 ‰ (spring, while malonic acid is more enriched in 13C than others in autumn (−17.6 ± 4.6 ‰ and summer (−18.7 ± 4.0 ‰. The δ13C values of major species in Beijing aerosols are generally lower than those in the western North Pacific atmosphere, the downwind region, which indicates that stable carbon isotopic compositions of diacids depend on their precursor sources in Beijing. Therefore, our

  3. Molecular distribution and compound-specific stable carbon isotopic composition of dicarboxylic acids, oxocarboxylic acids and α-dicarbonyls in PM2.5 from Beijing, China

    Science.gov (United States)

    Zhao, Wanyu; Kawamura, Kimitaka; Yue, Siyao; Wei, Lianfang; Ren, Hong; Yan, Yu; Kang, Mingjie; Li, Linjie; Ren, Lujie; Lai, Senchao; Li, Jie; Sun, Yele; Wang, Zifa; Fu, Pingqing

    2018-02-01

    This study investigates the seasonal variation, molecular distribution and stable carbon isotopic composition of diacids, oxocarboxylic acids and α-dicarbonyls to better understand the sources and formation processes of fine aerosols (PM2.5) in Beijing. The concentrations of total dicarboxylic acids varied from 110 to 2580 ng m-3, whereas oxoacids (9.50-353 ng m-3) and dicarbonyls (1.50-85.9 ng m-3) were less abundant. Oxalic acid was found to be the most abundant individual species, followed by succinic acid or occasionally by terephthalic acid (tPh), a plastic waste burning tracer. Ambient concentrations of phthalic acid (37.9 ± 27.3 ng m-3) and tPh (48.7 ± 51.1 ng m-3) were larger in winter than in other seasons, illustrating that fossil fuel combustion and plastic waste incineration contribute more to wintertime aerosols. The year-round mass concentration ratios of malonic acid to succinic acid (C3 / C4) were relatively low by comparison with those in other urban aerosols and remote marine aerosols. The values were less than or equal to unity in Beijing, implying that the degree of photochemical formation of diacids in Beijing is insignificant. Moreover, strong correlation coefficients of major oxocarboxylic acids and α-dicarbonyls with nss-K+ suggest that biomass burning contributes significantly to these organic acids and related precursors. The mean δ13C value of succinic acid is the highest among all species, with values of -17.1 ± 3.9 ‰ (winter) and -17.1 ± 2.0 ‰ (spring), while malonic acid is more enriched in 13C than others in autumn (-17.6 ± 4.6 ‰) and summer (-18.7 ± 4.0 ‰). The δ13C values of major species in Beijing aerosols are generally lower than those in the western North Pacific atmosphere, the downwind region, which indicates that stable carbon isotopic compositions of diacids depend on their precursor sources in Beijing. Therefore, our study demonstrates that in addition to photochemical oxidation, high abundances of diacids

  4. Water and carbon stable isotope records from natural archives: a new database and interactive online platform for data browsing, visualizing and downloading

    Science.gov (United States)

    Bolliet, Timothé; Brockmann, Patrick; Masson-Delmotte, Valérie; Bassinot, Franck; Daux, Valérie; Genty, Dominique; Landais, Amaelle; Lavrieux, Marlène; Michel, Elisabeth; Ortega, Pablo; Risi, Camille; Roche, Didier M.; Vimeux, Françoise; Waelbroeck, Claire

    2016-08-01

    Past climate is an important benchmark to assess the ability of climate models to simulate key processes and feedbacks. Numerous proxy records exist for stable isotopes of water and/or carbon, which are also implemented inside the components of a growing number of Earth system model. Model-data comparisons can help to constrain the uncertainties associated with transfer functions. This motivates the need of producing a comprehensive compilation of different proxy sources. We have put together a global database of proxy records of oxygen (δ18O), hydrogen (δD) and carbon (δ13C) stable isotopes from different archives: ocean and lake sediments, corals, ice cores, speleothems and tree-ring cellulose. Source records were obtained from the georeferenced open access PANGAEA and NOAA libraries, complemented by additional data obtained from a literature survey. About 3000 source records were screened for chronological information and temporal resolution of proxy records. Altogether, this database consists of hundreds of dated δ18O, δ13C and δD records in a standardized simple text format, complemented with a metadata Excel catalog. A quality control flag was implemented to describe age markers and inform on chronological uncertainty. This compilation effort highlights the need to homogenize and structure the format of datasets and chronological information as well as enhance the distribution of published datasets that are currently highly fragmented and scattered. We also provide an online portal based on the records included in this database with an intuitive and interactive platform (http://climateproxiesfinder.ipsl.fr/), allowing one to easily select, visualize and download subsets of the homogeneously formatted records that constitute this database, following a choice of search criteria, and to upload new datasets. In the last part, we illustrate the type of application allowed by our database by comparing several key periods highly investigated by the

  5. Stable Carbon Isotope Composition of the Lipids in Natural Ophiocordyceps sinensis from Major Habitats in China and Its Substitutes.

    Science.gov (United States)

    Guo, Lian-Xian; Xu, Xiao-Ming; Hong, Yue-Hui; Li, Yan; Wang, Jiang-Hai

    2017-09-18

    Ophiocordyceps sinensis is one rare medicinal fungus produced in the Qinghai-Tibetan Plateau. Its quality and price varies hugely with different habitat, and its numerous substitutes have sprung up in functional food markets. This paper aims to discriminate the geographic origin of wild O. sinensis and its substitutes via element analyzer-isotope ratio mass spectrometry and gas chromatography-isotope ratio mass spectrometry. The δ 13 C values of major fatty acids in the lipids of O. sinensis are characterized unanimously by the variation relation C 18:0 sinensis suggests that the δ 13 C patterns may be sensitive potential indicators to discriminate its geographical origin. The δ 13 C values of individual major fatty acids of lipids from the cultivated stromata of Cordyceps militaris (SCM), the fermented mycelia of Hirsurella sinensis (FM H ) and Paecilomyces epiali (FM P ) range from -31.2‰ to -29.7‰, -16.9‰ to -14.3‰, and -26.5‰ to -23.9‰, respectively. Their δ 13 C pattern of individual major fatty acids may be used as a potential indicator to discriminate the products of natural O. sinensis and its substitutes.

  6. Carbon Stable-Isotope and Physicochemical Data as a Possible Tool to Differentiate between Honey-Production Environments in Uruguay

    Directory of Open Access Journals (Sweden)

    Verónica Berriel

    2018-06-01

    Full Text Available The allocation of honey origin is an increasingly important issue worldwide as it is closely related to product quality and consumer preference. In South America, honeys produced in grasslands and eucalyptus or native forests are preferred at the regional level, so their differentiation is essential to assure consumers of their authenticity according to their productive system. The objective of this study was to differentiate honeys produced in three environments: one, a monoculture system based on the eucalyptus forest, and two others based in natural environments of grasslands and native forests. To do this, honey’s physicochemical and isotopic variables (pH, free acidity, lactic acid content, moisture, total sugar content, and honey and extracted protein 13C isotopic composition were analysed. Discriminant analysis applied to the data revealed that, based on the selected variables, it was impossible to differentiate the three groups of honeys due to the superposition of those produced in grasslands and native forests. For this reason, a group of honeys derived from native and polyfloral environments (grasslands and native forests was formed and subjected to discriminant analysis (DA, together with the group of honeys derived from a commercial plantation of eucalyptus forest. The model obtained in this case achieved 100% correct allocation both at the training stage and the cross-validation stage.

  7. Carbon and oxygen isotope compositions of the carbonate facies

    Indian Academy of Sciences (India)

    The Vindhyan sedimentary succession in central India spans a wide time bracket from the Paleopro- terozoic to the Neoproterozoic period.Chronostratigraphic significance of stable carbon and oxygen isotope ratios of the carbonate phase in Vindhyan sediments has been discussed in some recent studies.However,the ...

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

    Science.gov (United States)

    Laceby, J. Patrick; Huon Huon, Sylvain; Onda, Yuichi; Evrard, Olivier

    2016-04-01

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

  9. Pan-Arctic concentrations of mercury and stable isotope ratios of carbon (δ{sup 13}C) and nitrogen (δ{sup 15}N) in marine zooplankton

    Energy Technology Data Exchange (ETDEWEB)

    Pomerleau, Corinne, E-mail: corinne.pomerleau@umanitoba.ca [Centre for Earth Observation Science, University of Manitoba, Winnipeg, MB R3T 2N2 (Canada); Greenland Institute of Natural Resources, Kivioq 2, Nuuk 3900, Greenland (Denmark); Stern, Gary A.; Pućko, Monika [Centre for Earth Observation Science, University of Manitoba, Winnipeg, MB R3T 2N2 (Canada); Foster, Karen L. [Foster Environmental, Peterborough, ON K9J 8L2 (Canada); Macdonald, Robie W. [Institute of Ocean Sciences, Fisheries and Oceans Canada, Sidney, BC V8L 4B2 (Canada); Fortier, Louis [Québec-Océan, Département de Biologie, Université Laval, Québec, QC G1V 0A6 (Canada)

    2016-05-01

    Zooplankton play a central role in marine food webs, dictating the quantity and quality of energy available to upper trophic levels. They act as “keystone” species in transfer of mercury (Hg) up through the marine food chain. Here, we present the first Pan-Arctic overview of total and monomethylmercury concentrations (THg and MMHg) and stable isotope ratios of carbon (δ{sup 13}C) and nitrogen (δ{sup 15}N) in selected zooplankton species by assembling data collected between 1998 and 2012 from six arctic regions (Laptev Sea, Chukchi Sea, southeastern Beaufort Sea, Canadian Arctic Archipelago, Hudson Bay and northern Baffin Bay). MMHg concentrations in Calanus spp., Themisto spp. and Paraeuchaeta spp. were found to increase with higher δ{sup 15}N and lower δ{sup 13}C. The southern Beaufort Sea exhibited both the highest THg and MMHg concentrations. Biomagnification of MMHg between Calanus spp. and two of its known predators, Themisto spp. and Paraeuchaeta spp., was greatest in the southern Beaufort Sea. Our results show large geographical variations in Hg concentrations and isotopic signatures for individual species related to regional ecosystem features, such as varying water masses and freshwater inputs, and highlight the increased exposure to Hg in the marine food chain of the southern Beaufort Sea. - Highlights: • Assessment of Pan-Arctic variability in zooplankton Hg concentrations • Increased exposure to Hg in the marine food chain of the southern Beaufort Sea • Zooplankton plays a central role in the Hg pathway within Arctic marine food webs.

  10. Recent applications of stable isotopes in environmental medicine in germany

    International Nuclear Information System (INIS)

    Krumbiegel, P.; Herbarth, O.

    2000-01-01

    In the last few years, a new quality in the application of stable isotopes became manifest. It is the establishment of stable isotopes as a tool in medical routine diagnosis - a novel field of nuclear medicine - and in environmental-medical epidemiological surveys. Owing to missing suitable radioactive isotopes of the bio elements carbon and nitrogen and because of ethical problems in the human use of some radionuclides, the stable isotopes 13 C and 1% N play a key role in this new field. A review is given about four new stable isotope-aided methods for in vivo organ function test. Three of them were developed in Leipzig, germany, and one in houston/Texas. We have validated the tests and then introduced into medical and environmental routine diagnostic use: ( 15 N Methacetin and ( 13 C) methacetin liver function tests to characterize the detoxification capacity of the human liver; ( 15 N) Urea and ( 13 C) urea tests to detect the colonization of the human stomach by the bacterium helicobacter pylori. This bacterium is, as known, responsible for gastritis and ulcer of the gastrointestinal tract. The transmission ways of H. Pylori are under investigation world-wide

  11. Transfer of organic carbon through marine water columns to sediments – insights from stable and radiocarbon isotopes of lipid biomarkers

    OpenAIRE

    S. G. Wakeham; A. P. McNichol

    2014-01-01

    Compound-specific 13C and 14C compositions of diverse lipid biomarkers (fatty acids, alkenones, hydrocarbons, sterols and fatty alcohols) were measured in sinking particulate matter collected in sediment traps and from underlying surface sediments in the Black Sea, the Arabian Sea and the Ross Sea. The goal was to develop a multiparameter approach to constrain relative inputs of organic carbon (OC) from marine biomass, terrigenous vascular-plant and relict-kerogen sources. U...

  12. Deciphering biodegradation effects on light hydrocarbons in crude oils using their stable carbon isotopic composition: a case study from the Gullfaks oil field, offshore Norway

    OpenAIRE

    Andrea Vieth-Hillebrand [Vieth; Heinz Wilkes

    2006-01-01

    Compound-specific isotope analysis has become an important tool in environmental studies and is an especially powerful way to evaluate biodegradation of hydrocarbons. Here, carbon isotope ratios of light hydrocarbons were used to characterise in-reservoir biodegradation in the Gullfaks oil field, offshore Norway. Increasing biodegradation, as characterised, for example, by increasing concentration ratios of Pr/n-C17 and Ph/n-C18, and decreasing concentrations of individual light hydrocarbons ...

  13. Temporal changes in carbon and nitrogen stable isotope ratios of macrozoobenthos on an artificial tidal flat facing a hypertrophic canal, inner Tokyo Bay

    International Nuclear Information System (INIS)

    Kanaya, Gen; Nakamura, Yasuo; Koizumi, Tomoyoshi; Yamada, Katsumasa; Koshikawa, Hiroshi; Kohzu, Ayato; Maki, Hideaki

    2013-01-01

    Highlights: • Temporal changes in food web structure were analyzed in a tidal flat in a hypertrophic coastal bay. • Microphytobenthos mainly supported the benthic food web throughout seasons. • Phytoplankton and terrestrial detritus were utilized after red tides and urban runoffs. • Seasonal changes in consumer-δ 15 N was much larger in inner Tokyo Bay than in other estuaries. • This study showed specific characteristics of benthic food web in highly urbanized estuaries. -- Abstract: Temporal changes in benthic food web structure were analyzed in an artificial tidal flat in inner Tokyo Bay, Japan, using carbon and nitrogen stable isotope ratios (δ 13 C and δ 15 N). Microphytobenthos were the most important food sources of macrozoobenthos, due to high microphytobenthic biomass on the tidal flat, while phytoplankton in canal water (canal POM PP ), terrestrial materials from urban surface runoff (canal POM TM ), and marsh plants were less important. Dietary contribution of microphytobenthos was highest in April to June, while decreased towards December owing to the supply of canal POM PP and canal POM TM following red tides and heavy rainfall events in summer to fall. Temporal changes in δ 15 N (Δδ 15 N) of consumer corresponded well to the 15 N-enrichment in canal POM PP in summer. A meta-analysis showed that the consumer-Δδ 15 N was considerably larger in inner Tokyo Bay than those in other estuaries, which may be a specific characteristic of benthic food web in highly urbanized estuaries

  14. Effects of sex and altitude on nutrient, and carbon and nitrogen stable isotope composition of the endangered shrub Baccharis concinna G.M. Barroso (Asteraceae

    Directory of Open Access Journals (Sweden)

    G. Wilson Fernandes

    Full Text Available ABSTRACT Previous ecological studies of dioecious plant species have found that female plants preferentially occur at lower altitudes where there are typically better nutritional conditions, while male plants often occur in less favorable sites. We compared the ecophysiological performance of male and female plants in three populations of the dioecious Baccharis concinna, an endemic species of rupestrian grasslands of Serra do Cipó, in southeastern Brazil. We hypothesized that physiological differences between the sexes would explain the distribution patterns of the populations. Analyses of the tissue content of phosphorus (P, calcium (Ca, potassium (K and sodium (Na, and carbon and nitrogen stable isotopes, were used to assess nutritional status and water use efficiency (WUE in plant leaves, stems and roots of male and female plants in three populations located along an elevational gradient. Differences among populations were related to decreased nutrient levels and WUE at higher elevations, but an effect of sex was found only for %C, with male plants having slightly higher values. In conclusion, the sex ratios in the studied populations of B. concinna could not be attributed to differences in nutrient acquisition and WUE.

  15. Western Indian Ocean circulation and climate variability on different time scales. A study based on stable oxygen and carbon isotopes, benthic foraminiferal assemblages and Mg/Ca paleothermometry

    Energy Technology Data Exchange (ETDEWEB)

    Romahn, Sarah

    2014-08-19

    In order to understand the Earth's climate evolution it is crucial to evaluate the role of low-latitude oceans in the global climate system, as they are connected to both hemispheres via atmospheric and oceanic circulation and thus hold the potential to disentangle the asynchronicity of short-term Pleistocene climate variability. However, the potential of low latitude oceans to respond to and force large-scale changes of the climate system is still debated. The aim of this thesis is to examine and to understand the causal relationship of both atmospheric and oceanic changes in the tropical western Indian Ocean on centennial-, millennial and glacial-interglacial timescales. For this purpose I investigated stable oxygen and carbon isotope compositions of both planktic and benthic foraminiferal tests, Mg/Ca ratios of planktic foraminiferal tests as well as benthic foraminiferal assemblages and sedimentary geochemical parameters on two sediment cores (GeoB12615-4, 446 m and GeoB12616-4, 1449 m) from the continental slope off Tanzania, East Africa.

  16. Evaluation of autotrophic growth of ammonia-oxidizers associated with granular activated carbon used for drinking water purification by DNA-stable isotope probing.

    Science.gov (United States)

    Niu, Jia; Kasuga, Ikuro; Kurisu, Futoshi; Furumai, Hiroaki; Shigeeda, Takaaki

    2013-12-01

    Nitrification is an important biological function of granular activated carbon (GAC) used in advanced drinking water purification processes. Newly discovered ammonia-oxidizing archaea (AOA) have challenged the traditional understanding of ammonia oxidation, which considered ammonia-oxidizing bacteria (AOB) as the sole ammonia-oxidizers. Previous studies demonstrated the predominance of AOA on GAC, but the contributions of AOA and AOB to ammonia oxidation remain unclear. In the present study, DNA-stable isotope probing (DNA-SIP) was used to investigate the autotrophic growth of AOA and AOB associated with GAC at two different ammonium concentrations (0.14 mg N/L and 1.4 mg N/L). GAC samples collected from three full-scale drinking water purification plants in Tokyo, Japan, had different abundance of AOA and AOB. These samples were fed continuously with ammonium and (13)C-bicarbonate for 14 days. The DNA-SIP analysis demonstrated that only AOA assimilated (13)C-bicarbonate at low ammonium concentration, whereas AOA and AOB exhibited autotrophic growth at high ammonium concentration. This indicates that a lower ammonium concentration is preferable for AOA growth. Since AOA could not grow without ammonium, their autotrophic growth was coupled with ammonia oxidation. Overall, our results point towards an important role of AOA in nitrification in GAC filters treating low concentration of ammonium. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Evaluation of nutrient and energy sources of the deepest known serpentinite-hosted ecosystem using stable carbon, nitrogen, and sulfur isotopes.

    Science.gov (United States)

    Onishi, Yuji; Yamanaka, Toshiro; Okumura, Tomoyo; Kawagucci, Shinsuke; Watanabe, Hiromi Kayama; Ohara, Yasuhiko

    2018-01-01

    The Shinkai Seep Field (SSF) in the southern Mariana forearc discovered in 2010 is the deepest (~5,700 m in depth) known serpentinite-hosted ecosystem dominated by a vesicomyid clam, Calyptogena (Abyssogena) mariana. The pioneering study presumed that the animal communities are primary sustained by reducing fluid originated from the serpentinization of mantle peridotite. For understanding the nutrient and energy sources for the SSF community, this study conducted four expeditions to the SSF and collected additional animal samples such as polychaetes and crustaceans as well as sediments, fragments of chimneys developing on fissures of serpentinized peridotite, seeping fluid on the chimneys, and pore water within the chimneys. Geochemical analyses of seeping fluids on the chimneys and pore water of the chimneys revealed significantly high pH (~10) that suggest subseafloor serpentinization controlling fluid chemistry. Stable isotope systematics (carbon, nitrogen, and sulfur) among animals, inorganic molecules, and environmental organic matter suggest that the SSF animal community mostly relies on the chemosynthetic production while some organisms appear to partly benefit from photosynthetic production despite the great depth of SSF.

  18. Western Indian Ocean circulation and climate variability on different time scales. A study based on stable oxygen and carbon isotopes, benthic foraminiferal assemblages and Mg/Ca paleothermometry

    International Nuclear Information System (INIS)

    Romahn, Sarah

    2014-01-01

    In order to understand the Earth's climate evolution it is crucial to evaluate the role of low-latitude oceans in the global climate system, as they are connected to both hemispheres via atmospheric and oceanic circulation and thus hold the potential to disentangle the asynchronicity of short-term Pleistocene climate variability. However, the potential of low latitude oceans to respond to and force large-scale changes of the climate system is still debated. The aim of this thesis is to examine and to understand the causal relationship of both atmospheric and oceanic changes in the tropical western Indian Ocean on centennial-, millennial and glacial-interglacial timescales. For this purpose I investigated stable oxygen and carbon isotope compositions of both planktic and benthic foraminiferal tests, Mg/Ca ratios of planktic foraminiferal tests as well as benthic foraminiferal assemblages and sedimentary geochemical parameters on two sediment cores (GeoB12615-4, 446 m and GeoB12616-4, 1449 m) from the continental slope off Tanzania, East Africa.

  19. Multiproxy Holocene paleoclimate records from the southern Peruvian Andes - what new can we learn from the stable carbon isotope composition of high altitude organic matter deposits?

    Science.gov (United States)

    Skrzypek, Grzegorz; Engel, Zbyněk

    2015-04-01

    Interpretation of the Central Andean paleoclimate over the last millennia still represents a research challenge demanding deeper studies [1,2]. Several high-resolution paleoclimate proxies for the last 10,000 years have been developed for the northern hemisphere. However, similar proxies are very limited for South America, particularly for high altitudes where, for example, tree-ring chronologies are not available and instrumental records are very limited. Consequently, our knowledge of high altitude climate changes in arid regions of the Peruvian Andes mainly relies on ice-core and lake deposit studies. In our study, we used a new alternative proxy for interpretation of palaeoclimate conditions based on a peat core taken from the Carhuasanta Valley at the foot of Nevado Mismi in the southern Peruvian Andes (15° 30'S, 71° 43'W, 4809m a.s.l.). The stable carbon isotope composition (δ13C) of Distichia peat reflects mainly the relative variation of the mean air temperature during subsequent growing seasons [3], and allows reconstructions of palaeotemperature changes. In contrast, peat organic carbon concentration (C % wt) records mainly wetness in the valley, directly corresponding to the changes in runoff in the upper part of the catchment. The most prominent climate changes recorded in the peat over last 4ka occurred between 3040 and 2750 cal. yrs BP. The initial warming turned to a very rapid cooling to temperatures at least 2° C lower than the mean for the Late Holocene. Initially drier conditions within this event turned to a short wet phase after 2780 cal. yrs BP, when the temperature increased again. This event coincides with significant changes in peat and ice core records in the Central Andes that match the timing of the global climate event around 2.8 cal. ka BP. Climatic conditions in the study area became relatively dry and stable after the event for about 800 years. Highly variable temperatures and humidity prevailed during the last 2000 years, when

  20. Breeding Westland petrels as providers of detrital carbon and nitrogen for soil arthropods : a stable isotope study

    International Nuclear Information System (INIS)

    Hawke, D.J.; Clark, J.M.; Vallance, J.R.

    2013-01-01

    Seabirds deposit large quantities of marine detritus on land, but little is known of the soil arthropods processing this material. Burrow-nesting seabirds concentrate their activities within their burrows, so we tested the hypothesis that burrow arthropod fauna is more marine-like in its isotopic enrichment ( 13 C/ 12 C, 15 N/ 14 N); expressed as δ 13 C and δ 15 N) than the arthropods on the adjacent forest floor. Results from a Westland petrel (Procellaria westlandica) colony on the South Island of New Zealand did not support the hypothesis. Instead, δ 15 N was universally marine (13-22 per mil). While δ 13 C separated into two clusters, the distribution was not according to arthropod provenance. Most taxa had a terrestrial δ 13 C; only two taxa (a leiodid beetle and the mesostigmatic mite Ayersacarus woodi) incorporated marine C. The leiodid beetle occurs both in burrows and on the forest floor; beetles from both habitats had a marine δ 13 C. Ayersacarus woodi is found only in burrows. We conclude that, in this system, marine and terrestrial detrital C is processed separately, and that marine detrital C enters the terrestrial ecosystem through a very few arthropod taxa. (author). 33 refs., 1 fig.

  1. Authenticity testing of environment-friendly Korean rice (Oryza sativa L.) using carbon and nitrogen stable isotope ratio analysis.

    Science.gov (United States)

    Chung, Ill-Min; Park, Sung-Kyu; Lee, Kyoung-Jin; An, Min-Jeong; Lee, Ji-Hee; Oh, Yong-Taek; Kim, Seung-Hyun

    2017-11-01

    The increasing demand for organic foods creates, in turn, a pressing need for the development of more accurate tools for the authentication of organic food in order to ensure both fair trade and food safety. This study examines the feasibility of δ 13 C and δ 15 N analyses as potential tools for authentication of environment-friendly rice sold in Korea. δ 13 C and δ 15 N examination in different rice grains showed that environment-friendly rice can be successfully distinguished from conventional rice. No multi-residue pesticides were detected in the examined rice samples, including conventional rice. This study demonstrates the complementary feasibility of δ 13 C and δ 15 N analyses for the authentication of environment-friendly rice sold in Korea in cases where pesticide residue analysis alone is insufficient for discrimination of organic and conventional rice. In future, complementary analyses including compound-specific isotope ratio analysis might be employed for improving the reliability of organic authentication. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Stereoselective synthesis of stable-isotope-labeled amino acids

    Energy Technology Data Exchange (ETDEWEB)

    Unkefer, C.J.; Martinez, R.A.; Silks, L.A. III [Los Alamos National Laboratory, NM (United States); Lodwig, S.N. [Centralia College, WA (United States)

    1994-12-01

    For magnetic resonance and vibrational spectroscopies to reach their full potential, they must be used in combination with sophisticated site-specific stable isotope labeling of biological macromolecules. Labeled amino acids are required for the study of the structure and function of enzymes and proteins. Because there are 20 common amino acids, each with its own distinguishing chemistry, they remain a synthetic challenge. The Oppolzer chiral auxiliary provides a general tool with which to approach the synthesis of labeled amino acids. By using the Oppolzer auxiliary, amino acids can be constructed from several small molecules, which is ideal for stable isotope labeling. In addition to directing the stereochemistry at the {alpha}-carbon, the camphorsultam can be used for stereo-specific isotope labeling at prochiral centers in amino acids. By using the camphorsultam auxiliary we have the potential to synthesize virtually any isotopomer of all of the common amino acids.

  3. Stereoselective synthesis of stable-isotope-labeled amino acids

    International Nuclear Information System (INIS)

    Unkefer, C.J.; Martinez, R.A.; Silks, L.A. III; Lodwig, S.N.

    1994-01-01

    For magnetic resonance and vibrational spectroscopies to reach their full potential, they must be used in combination with sophisticated site-specific stable isotope labeling of biological macromolecules. Labeled amino acids are required for the study of the structure and function of enzymes and proteins. Because there are 20 common amino acids, each with its own distinguishing chemistry, they remain a synthetic challenge. The Oppolzer chiral auxiliary provides a general tool with which to approach the synthesis of labeled amino acids. By using the Oppolzer auxiliary, amino acids can be constructed from several small molecules, which is ideal for stable isotope labeling. In addition to directing the stereochemistry at the α-carbon, the camphorsultam can be used for stereo-specific isotope labeling at prochiral centers in amino acids. By using the camphorsultam auxiliary we have the potential to synthesize virtually any isotopomer of all of the common amino acids

  4. Biomarker and stable carbon isotopic signatures for 100–200 year sediment record in the Chaihe catchment in southwest China

    International Nuclear Information System (INIS)

    Wang, Yanhua; Yang, Hao; Zhang, Jixiang; Xu, Meina; Wu, Changbin

    2015-01-01

    Natural inputs and anthropogenic influences on lakes and their catchments are reflected in the sediment record. In the present study, the extractable organic compounds from sediments in the Chaihe catchment of the Dianchi watershed were analyzed to characterize source inputs. Results show that the sediments are dominated by odd numbered n-alkanes (n-C 16 –n-C 33 ), maximizing at n-C 17 , n-C 29 and n-C 31 . Aliphatic hydrocarbon may be composed of terrestrial plants and bacteria. The values of δ 13 C 27 , δ 13 C 29 and δ 13 C 31 of n-alkanes exhibit a range from − 33.27‰ to − 25.46‰, from − 35.76‰ to − 28.47‰ and from − 33.67‰ to − 27.42‰, respectively and three records strongly covary with depth, falling within the range of C 3 plants in the study area. An isotopic model revealed C 3 plant contribution to sedimentary organic matter (OM) ranging from 40.75% to 97.22%. The values of ACL 27–33 , CPI 27–33 , OEP, Paq, Pr/Ph, (C 27 + C 29 )/2C 31 , (C 21 + C 23 + C 25 )/3C 17 and nC 26 − /nC 27 + are consistent with the C 3 plant predominance. A constant CRS model gave the accumulation rates ranging from 2.69 to 8.46 mm a −1 spanning 1885–2010. It was concluded that OM transport in the Chaihe catchment was influenced strongly by human activities resulting in enhanced eutrophication. - Highlights: • Strong predominance of odd-numbered n-alkanes maximized at n-C 17 , n-C 29 and n-C 31 • Sedimentary OM in the Chaihe catchment was deduced mainly from C 3 plants. • Human activities enhanced OM transport, resulting in worse ecosystem

  5. Carbon and oxygen stable isotopes of selected Cenomanian and Turonian rudists from Egypt and Czech Republic, and a note on changes in rudist diversity

    Czech Academy of Sciences Publication Activity Database

    El-Shazly, S.; Košťák, M.; Abdel-Gawad, G.; Kloučková, B.; Saber, G. S.; Salama, Y. F.; Mazuch, M.; Žák, Karel

    2011-01-01

    Roč. 86, č. 2 (2011), s. 209-226 ISSN 1214-1119 Institutional research plan: CEZ:AV0Z30130516 Keywords : rudists * Upper Cretaceous * Cenomanian * Turonian * paleoecology * C and O stable isotopes * Upper Cretaceous (Egypt) * Upper Cretaceous (Czech Republic) Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.099, year: 2011

  6. Innovative method for carbon dioxide determination in human postmortem cardiac gas samples using headspace-gas chromatography–mass spectrometry and stable labeled isotope as internal standard

    Energy Technology Data Exchange (ETDEWEB)

    Varlet, V., E-mail: vincent.varlet@chuv.ch [Toxicology and Forensic Chemistry Unit, University Center of Legal Medicine Lausanne – Geneva, CH-1011 Lausanne (Switzerland); Smith, F. [Toxicology and Forensic Chemistry Unit, University Center of Legal Medicine Lausanne – Geneva, CH-1011 Lausanne (Switzerland); Froidmont, S. de; Dominguez, A.; Rinaldi, A. [Forensic Medicine Unit, University Center of Legal Medicine Lausanne – Geneva, CH-1011 Lausanne (Switzerland); Augsburger, M. [Toxicology and Forensic Chemistry Unit, University Center of Legal Medicine Lausanne – Geneva, CH-1011 Lausanne (Switzerland); Mangin, P.; Grabherr, S. [Forensic Medicine Unit, University Center of Legal Medicine Lausanne – Geneva, CH-1011 Lausanne (Switzerland)

    2013-06-19

    Graphical abstract: -- Highlights: •We developed a method for CO{sub 2} analysis in cardiac samples and quantification by {sup 13}CO{sub 2}. •This method was fully validated by accuracy profile. •We have applied this method to perform CO{sub 2} precise quantification for forensic applications. •Context of the death could be documented following CO{sub 2} concentrations. -- Abstract: A novel approach to measure carbon dioxide (CO{sub 2}) in gaseous samples, based on a precise and accurate quantification by {sup 13}CO{sub 2} internal standard generated in situ is presented. The main goal of this study was to provide an innovative headspace-gas chromatography–mass spectrometry (HS-GC–MS) method applicable in the routine determination of CO{sub 2}. The main drawback of the GC methods discussed in the literature for CO{sub 2} measurement is the lack of a specific internal standard necessary to perform quantification. CO{sub 2} measurement is still quantified by external calibration without taking into account analytical problems which can often occur considering gaseous samples. To avoid the manipulation of a stable isotope-labeled gas, we have chosen to generate in situ an internal labeled standard gas ({sup 13}CO{sub 2}) on the basis of the stoichiometric formation of CO{sub 2} by the reaction of hydrochloric acid (HCl) with sodium hydrogen carbonate (NaH{sup 13}CO{sub 3}). This method allows a precise measurement of CO{sub 2} concentration and was validated on various human postmortem gas samples in order to study its efficiency.

  7. Biomarker and stable carbon isotopic signatures for 100–200 year sediment record in the Chaihe catchment in southwest China

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yanhua, E-mail: wangyanhua@njnu.edu.cn [School of Geography Science, Nanjing Normal University, 1 Wenyuan Road, Qixia, Nanjing 210023 (China); Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application (China); Yang, Hao [School of Geography Science, Nanjing Normal University, 1 Wenyuan Road, Qixia, Nanjing 210023 (China); Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application (China); Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control (China); Zhang, Jixiang [College of Economics and Management, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Baixia, Nanjing 210016 (China); Xu, Meina; Wu, Changbin [School of Geography Science, Nanjing Normal University, 1 Wenyuan Road, Qixia, Nanjing 210023 (China)

    2015-01-01

    Natural inputs and anthropogenic influences on lakes and their catchments are reflected in the sediment record. In the present study, the extractable organic compounds from sediments in the Chaihe catchment of the Dianchi watershed were analyzed to characterize source inputs. Results show that the sediments are dominated by odd numbered n-alkanes (n-C{sub 16}–n-C{sub 33}), maximizing at n-C{sub 17}, n-C{sub 29} and n-C{sub 31}. Aliphatic hydrocarbon may be composed of terrestrial plants and bacteria. The values of δ{sup 13}C{sub 27}, δ{sup 13}C{sub 29} and δ{sup 13}C{sub 31} of n-alkanes exhibit a range from − 33.27‰ to − 25.46‰, from − 35.76‰ to − 28.47‰ and from − 33.67‰ to − 27.42‰, respectively and three records strongly covary with depth, falling within the range of C{sub 3} plants in the study area. An isotopic model revealed C{sub 3} plant contribution to sedimentary organic matter (OM) ranging from 40.75% to 97.22%. The values of ACL{sub 27–33}, CPI{sub 27–33}, OEP, Paq, Pr/Ph, (C{sub 27} + C{sub 29})/2C{sub 31}, (C{sub 21} + C{sub 23} + C{sub 25})/3C{sub 17} and nC{sub 26}{sup −}/nC{sub 27}{sup +} are consistent with the C{sub 3} plant predominance. A constant CRS model gave the accumulation rates ranging from 2.69 to 8.46 mm a{sup −1} spanning 1885–2010. It was concluded that OM transport in the Chaihe catchment was influenced strongly by human activities resulting in enhanced eutrophication. - Highlights: • Strong predominance of odd-numbered n-alkanes maximized at n-C{sub 17}, n-C{sub 29} and n-C{sub 31} • Sedimentary OM in the Chaihe catchment was deduced mainly from C{sub 3} plants. • Human activities enhanced OM transport, resulting in worse ecosystem.

  8. The Effect of the Interannual Variability of the OH Sink on the Interannual Variability of the Atmospheric Methane Mixing Ratio and Carbon Stable Isotope Composition

    Science.gov (United States)

    Guillermo Nuñez Ramirez, Tonatiuh; Houweling, Sander; Marshall, Julia; Williams, Jason; Brailsford, Gordon; Schneising, Oliver; Heimann, Martin

    2013-04-01

    The atmospheric hydroxyl radical concentration (OH) varies due to changes in the incoming UV radiation, in the abundance of atmospheric species involved in the production, recycling and destruction of OH molecules and due to climate variability. Variability in carbon monoxide emissions from biomass burning induced by El Niño Southern Oscillation are particularly important. Although the OH sink accounts for the oxidation of approximately 90% of atmospheric CH4, the effect of the variability in the distribution and strength of the OH sink on the interannual variability of atmospheric methane (CH4) mixing ratio and stable carbon isotope composition (δ13C-CH4) has often been ignored. To show this effect we simulated the atmospheric signals of CH4 in a three-dimensional atmospheric transport model (TM3). ERA Interim reanalysis data provided the atmospheric transport and temperature variability from 1990 to 2010. We performed simulations using time dependent OH concentration estimations from an atmospheric chemistry transport model and an atmospheric chemistry climate model. The models assumed a different set of reactions and algorithms which caused a very different strength and distribution of the OH concentration. Methane emissions were based on published bottom-up estimates including inventories, upscaled estimations and modeled fluxes. The simulations also included modeled concentrations of atomic chlorine (Cl) and excited oxygen atoms (O(1D)). The isotopic signal of the sources and the fractionation factors of the sinks were based on literature values, however the isotopic signal from wetlands and enteric fermentation processes followed a linear relationship with a map of C4 plant fraction. The same set of CH4emissions and stratospheric reactants was used in all simulations. Two simulations were done per OH field: one in which the CH4 sources were allowed to vary interannually, and a second where the sources were climatological. The simulated mixing ratios and

  9. Forensic analysis of explosives using isotope ratio mass spectrometry (IRMS)--part 2: forensic inter-laboratory trial: bulk carbon and nitrogen stable isotopes in a range of chemical compounds (Australia and New Zealand).

    Science.gov (United States)

    Benson, Sarah J; Lennard, Christopher J; Maynard, Philip; Hill, David M; Andrew, Anita S; Neal, Ken; Stuart-Williams, Hilary; Hope, Janet; Walker, G Stewart; Roux, Claude

    2010-01-01

    Comparability of data over time and between laboratories is a key issue for consideration in the development of global databases, and more broadly for quality assurance in general. One mechanism that can be utilized for evaluating traceability is an inter-laboratory trial. This paper addresses an inter-laboratory trial conducted across a number of Australian and New Zealand isotope ratio mass spectrometry (IRMS) laboratories. The main objective of this trial was to determine whether IRMS laboratories in these countries would record comparable values for the distributed samples. Four carbon containing and four nitrogen containing compounds were distributed to seven laboratories in Australia and one in New Zealand. The laboratories were requested to analyze the samples using their standard procedures. The data from each laboratory was evaluated collectively using International Standard ISO 13528 (Statistical methods for use in proficiency testing by inter-laboratory comparisons). "Warning signals" were raised against one participant in this trial. "Action signals" requiring corrective action were raised against four participants. These participants reviewed the data and possible sources for the discrepancies. This inter-laboratory trial was successful in providing an initial snapshot of the potential for traceability between the participating laboratories. The statistical methods described in this article could be used as a model for others needing to evaluate stable isotope results derived from multiple laboratories, e.g., inter-laboratory trials/proficiency testing. Ongoing trials will be conducted to improve traceability across the Australian and New Zealand IRMS community.

  10. Stable isotope separation by thermal diffusion

    International Nuclear Information System (INIS)

    Vasaru, Gheorghe

    2001-01-01

    Thermal diffusion in both gaseous and liquid phase has been subject of extensive experimental and theoretical investigations, especially after the invention of K. Clusius and G. Dickel of the thermal diffusion column, sixty three years ago. This paper gives a brief overview of the most important research and developments performed during the time at the National Institute for Research and Development for Isotopic and Molecular Technology (ITIM) at Cluj - Napoca, Romania in the field of separation of stable isotopes by thermal diffusion. An retrospective analysis of the research and results concerning isotope separation by thermal diffusion entails the following conclusions: - thermal diffusion is an adequate method for hydrogen isotope separation (deuterium and tritium) and for noble gas isotope separation (He, Ne, Ar, Kr, Xe); - thermal diffusion is attractive also for 13 C enrichment using methane as raw material for separation, when annual yields of up to 100 g are envisaged; - lately, the thermal diffusion appears to be chosen as a final enrichment step for 17 O. An obvious advantage of this method is its non-specificity, i.e. the implied equipment can be utilized for isotope separation of other chemical elements too. Having in view the low investment costs for thermal diffusion cascades the method appears economically attractive for obtaining low-scale, laboratory isotope production. The paper has the following content: 1. The principle of method; 2. The method's application; 3. Research in the field of thermal diffusion at ITIM; 4. Thermal diffusion cascades for N, C, Ne, Ar and Kr isotope separation; 5. Conclusion

  11. Transformation of soil organic matter in a Japanese larch forest. Radiocarbon and stable carbon isotope compositions versus soil depth

    International Nuclear Information System (INIS)

    Liu Wei; Moriizumi, Jun; Yamazawa, Hiromi; Iida, Takao

    2008-01-01

    Soil organic matter at a depth of 0-55 cm, collected from a Japanese larch forest area, was separated into particulate organic matter (size >53 μm), particulate organic matter (size 14 C and δ 13 C values were determined. The Δ 14 C values of particulate matters decreased greatly from 128 per mille to -278 per mille, indicating a relative increase of resistant organic components in particulate matters. That of humic acid matter decreased from 183 per mille to -139 per mille. For these of organic matter fractions at the same depth, the Δ 14 C values of particulate matter (size >53μm) are smallest and those of humic acid matter are the largest. That indicates that a high contribution of young organic matter to the humic acid matter exists and transformation tendency of particulate matter may be from coarse to small in the particulate size. Positive Δ 14 C values appeared at a depth of 10 cm, 25 cm, and 35 cm for the particulate organic matter (size >53μm), particulate organic matter (size 14 C values of the humic acid matter also infects that the bomb carbon has reached the depth of 35 cm. Additionally, the Δ 14 C values of these three kinds of organic matters ranged from 50 per mille to 183 per mille at a depth of 0-7 cm, which were not smaller than that of litter in the forest area, indicating high proportion of modern, plants-derived soil organic matter in this depth ranges. The δ 13 C values increased from -28 per mille to -23 per mille with the increase depth of 0-55 cm. The δ 13 C values of humic acid matter are approximately less than that of particulate matters at the same depth, which may be explained as a high contribution of young organic matter to the humic acid matter. (author)

  12. Utilization of stable isotopes in medicine

    International Nuclear Information System (INIS)

    1980-11-01

    The ten lectures given at this round table are presented together with a discussion. Five lectures, relating to studies in which deuterium oxide was employed as a tracer of body water, dealt with pulmonary water measurements in man and animals, the total water pool in adipose subjects, and liquid compartments in children undergoing hemodyalisis. The heavy water is analysed by infrared spectrometry and a new double spectrodoser is described. Two studies using 13 C as tracer, described the diagnosis of liver troubles and diabetes respectively. A general review of the perspectives of the application of stable isotopes in clinical medicine is followed by a comparison of the use of stable and radioactive isotopes in France [fr

  13. A 560 yr summer temperature reconstruction for the Western Mediterranean basin based on stable carbon isotopes from Pinus nigra ssp. laricio (Corsica/France

    Directory of Open Access Journals (Sweden)

    J. Kuhlemann

    2012-10-01

    Full Text Available The Mediterranean is considered as an area which will be affected strongly by current climate change. However, temperature records for the past centuries which can contribute to a better understanding of future climate changes are still sparse for this region. Carbon isotope chronologies from tree-rings often mirror temperature history but their application as climate proxies is difficult due to the influence of the anthropogenic change in atmospheric CO2 on the carbon isotope fractionation during photosynthetic CO2 uptake. We tested the influence of different correction models accounting for plant response to increased atmospheric CO2 on four annually resolved long-term carbon isotope records (between 400 and 800 yr derived from Corsican pine trees (Pinus nigra ssp. laricio growing at ecologically varying mountain sites on the island of Corsica. The different correction factors have only a minor influence on the main climate signals and resulting temperature reconstructions. Carbon isotope series show strong correlations with summer temperature and precipitation. A summer temperature reconstruction (1448–2007 AD reveals that the Little Ice Age was characterised by low, but not extremely low temperatures on Corsica. Temperatures have been to modern temperatures at around 1500 AD. The reconstruction reveals warm summers during 1480–1520 and 1950–2007 AD and cool summers during 1580–1620 and 1820–1890 AD.

  14. Stable Isotope Mapping of Alaskan Grasses and Marijuana

    Science.gov (United States)

    Booth, A. L.; Wooller, M. J.

    2008-12-01

    The spatial variation of isotope signatures in organic material is a useful forensic tool, particularly when applied to the task of tracking the production and distribution of plant-derived illicit drugs. In order to identify the likely grow-locations of drugs such as marijuana from unknown locations (i.e., confiscated during trafficking), base isotope maps are needed that include measurements of plants from known grow-locations. This task is logistically challenging in remote, large regions such as Alaska. We are therefore investigating the potential of supplementing our base (marijuana) isotope maps with data derived from other plants from known locations and with greater spatial coverage in Alaska. These currently include >150 samples of modern C3 grasses (Poaceae) as well as marijuana samples (n = 18) from known grow-locations across the state. We conducted oxygen, carbon and nitrogen stable isotope analyses of marijuana and grasses (Poaceae). Poaceae samples were obtained from the University of Alaska Fairbanks (UAF) Museum of the North herbarium collection, originally collected by field botanists from around Alaska. Results indicate that the oxygen isotopic composition of these grasses range from 10‰ to 30‰, and broadly mirror the spatial pattern of water isotopes in Alaska. Our marijuana samples were confiscated around the state of Alaska and supplied to us by the UAF Police Department. δ13C, δ15N and δ18O values exhibit geographic patterns similar to the modern grasses, but carbon and nitrogen isotopes of some marijuana plants appear to be influenced by additional factors related to indoor growing conditions (supplementary CO2 sources and the application of organic fertilizer). As well as providing a potential forensic resource, our Poaceae isotope maps could serve additional value by providing resources for studying ecosystem nutrient cycling, for tracing natural ecological processes (i.e., animal migration and food web dynamics) and providing

  15. Stable carbon and nitrogen isotopic composition of fine mode aerosols (PM2.5 over the Bay of Bengal: impact of continental sources

    Directory of Open Access Journals (Sweden)

    Srinivas Bikkina

    2016-07-01

    Full Text Available This study reports on stable carbon (δ13CTC and nitrogen (δ15NTN isotopic composition of total carbon and nitrogen (TC and TN in the fine mode aerosols (PM2.5; N=31 collected over the Bay of Bengal (BoB. The samples represent two distinct wind regimes during the cruise (27 December 2008–28 January 2009; one from the Indo-Gangetic Plain (referred as IGP-outflow and another from Southeast Asia (SEA-outflow. The PM2.5 samples from the IGP-outflow show higher δ13CTC (−25.0 to −22.8 ‰; −23.8±0.6 ‰ than those from the SEA-outflow (−27.4 to −24.7 ‰; −25.3±0.9 ‰. Similarly, δ15NTN varied from +11.8 to +30.6 ‰ (+20.4±5.4 ‰ and +10.4 to +31.7 ‰ (+19.4±6.1 ‰ for IGP- and SEA-outflows, respectively. Based on the literature data, MODIS-derived fire hotspots and back trajectories, we infer that higher δ13CTC in the IGP-outflow is predominantly associated with fossil fuel and biofuel combustion. In contrast, contribution of primary organic aerosols from the combustion of C3 plants or secondary organic aerosol (SOA formation from biomass/biofuel-burning emissions (BBEs can explain the lower δ13CTC values in the SEA-outflow. This inference is based on the significant linear correlations among δ13CTC, water-soluble organic carbon and non-sea-salt potassium (nss-K+, a proxy for BBEs in the SEA-outflow. A significant linear relationship of δ15N with and equivalent mass ratio of / is evident in both the continental outflows. Since abundance dominates the TN over the BoB (>90 %, atmospheric processes affecting its concentration in fine mode aerosols can explain the observed large variability of δ15NTN.

  16. Effects of air pollutants on the composition of stable carbon isotopes δ13C, of leaves and wood, and on leaf injury

    International Nuclear Information System (INIS)

    Martin, B.; Bytnerowicz, A.; Thorstenson, Y.R.

    1988-01-01

    Air pollutants are known to cause visible leaf injury as well as impairment of photosynthetic CO 2 fixation. Here we evaluate whether the effects on photosynthesis are large enough to cause changes in the relative composition of stable carbon isotopes, δ 13 C, of plant tissue samples, and, if so, how the changes relate to visual leaf injury. For that purpose, several woody and herbaceous plant species were exposed to SO 2 + O 3 and SO 2 + O 3 + NO 2 for one month. At the end of the fumigations, the plants were evaluated for visual leaf lesions, and δ 13 C of leaf tissue was determined. Woody plants generally showed less visual leaf injury and smaller effects on δ 13 C of pollutant exposure than did herbaceous plants. If δ 13 C was affected by pollutants, it became, with few exceptions, less negative. The data from the fumigation experiments were consistent with δ 13 C analyses of whole wood of annual growth rings from two conifer tree species, Pseudotsuga menziesii and Pinus strobus. These trees had been exposed until 1977 to exhaust gases from a gas plant at Lacq, France. Wood of both conifer species formed in the polluted air of 1972 to 1976 had less negative δ 13 C values than had wood formed in the much cleaner air in 1982 to 1986. No similar, time-dependent differences in δ 13 C of wood were observed in trees which had been continuously growing in clean air. Our δ 13 C data from both relatively short-term artificial exposures and long-term natural exposure are consistent with greater stomatal limitation of photosynthesis in polluted air than in clean air

  17. Stable isotopes. Enriched wheat: a new chance for nutrition research

    International Nuclear Information System (INIS)

    Chagvardieff, P.

    1996-01-01

    The Department of Plant Eco-physiology (DEV) from the CEA/Life Sciences Department of Cadarache (France) has artificially produced two kg of carbon 13 labelled wheat for nutrition research. It is the first successful stable isotope labelling of complex nutriments with a 10% enrichment in carbon 13. This wheat has been used for the manufacturing of pastas to follow the assimilation of nutrients by the organism. This short paper gives some details about the experimental procedure of labelled wheat cultivation. (J.S.)

  18. Diets of introduced predators using stable isotopes and stomach contents

    Science.gov (United States)

    Meckstroth, A.M.; Miles, A.K.; Chandra, S.

    2007-01-01

    In a study of predation on ground-nesting birds at South San Francisco Bay (South Bay), California, USA, we analyzed stomach contents and stable isotopes of carbon and nitrogen to identify commonly consumed prey. We obtained the stomach contents from 206 nonnative red foxes (Vulpes vulpes regalis) collected in the South Bay area and Monterey County during 1995-2001 and from 68 feral cats (Felis silvestris) from the South Bay area during 2001-2002. We determined prey identity, biomass, and frequency, described seasonal diet trends, and derived an Index of Relative Importance. Avian species were the most frequent prey we found in the stomachs of red foxes from South Bay (61%), whereas small rodents were most frequent for red foxes from Monterey County (62%). Small rodents were the most frequent prey we found in feral cats (63%). Carbon and nitrogen isotopic signatures for foxes supported stomach content findings. However, isotope results indicated that cats received a majority of their energy from a source other than rodents and outside the natural system, which differed from the stomach content analysis. We demonstrated the utility of both stable isotope and stomach content analyses to establish a more complete understanding of predators' diets. This information aids natural resource managers in planning and evaluating future predator-removal programs and increases our understanding of the impacts of nonnative foxes and cats on native species.

  19. 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.

  20. Stable isotopic analysis of Barnacle larvae and their faecal pellets to evaluate the ingested food

    Digital Repository Service at National Institute of Oceanography (India)

    Gaonkar, C.A.; Anil, A.C.

    Stable isotopes of carbon and nitrogen are useful in the evaluation of food web dynamics and have been used extensively in the feeding studies. Barnacles are dominant component of the intertidal and bio-fouling communities. Life cycle of barnacles...

  1. DNA stable-isotope probing (DNA-SIP).

    Science.gov (United States)

    Dunford, Eric A; Neufeld, Josh D

    2010-08-02

    DNA stable-isotope probing (DNA-SIP) is a powerful technique for identifying active microorganisms that assimilate particular carbon substrates and nutrients into cellular biomass. As such, this cultivation-independent technique has been an important methodology for assigning metabolic function to the diverse communities inhabiting a wide range of terrestrial and aquatic environments. Following the incubation of an environmental sample with stable-isotope labelled compounds, extracted nucleic acid is subjected to density gradient ultracentrifugation and subsequent gradient fractionation to separate nucleic acids of differing densities. Purification of DNA from cesium chloride retrieves labelled and unlabelled DNA for subsequent molecular characterization (e.g. fingerprinting, microarrays, clone libraries, metagenomics). This JoVE video protocol provides visual step-by-step explanations of the protocol for density gradient ultracentrifugation, gradient fractionation and recovery of labelled DNA. The protocol also includes sample SIP data and highlights important tips and cautions that must be considered to ensure a successful DNA-SIP analysis.

  2. Increase in soil stable carbon isotope ratio relates to loss of organic carbon: results from five long-term bare fallow experiments

    DEFF Research Database (Denmark)

    Menichetti, Lorenzo; Houot, Sabine; van Oort, Folkert

    2015-01-01

    Changes in the 12C/13C ratio (expressed as δ13C) of soil organic C (SOC) has been observed over long time scales and with depth in soil profiles. The changes are ascribed to the different reaction kinetics of 12C and 13C isotopes and the different isotopic composition of various SOC pool components...... examined. The overall estimate of the fractionation coefficient (ε) was −1.2 ± 0.3 ‰. This coefficient represents an important input to studies of long-term SOC dynamics in agricultural soils that are based on variations in 13C natural abundance. The variance of ε may be ascribed to site characteristics...... some impact on isotope abundance and fractionation....

  3. Stabilization of recent soil carbon in the humid tropics following land use changes: evidence from aggregate fractionation and stable isotope analyses

    OpenAIRE

    Paul, Sonja; Flessa, Heiner; Veldkamp, Edzo; López-Ulloa, Magdalena

    2008-01-01

    Keywords: Carbon sequestration - Ecuador - Mean residence time - Pasture - Secondary forest - Soil type - Texture - Water-stable aggregates Quantitative knowledge of stabilization- and decomposition processes is necessary to understand, assess and predict effects of land use changes on storage and stability of soil organic carbon (soil C) in the tropics. Although it is well documented that different soil types have different soil C stocks, it is presently unknown how different soil types a...

  4. Biomineralization and the carbon isotope record

    International Nuclear Information System (INIS)

    Degens, E.T.; Ittekkot, V.; Kazmierczak, J.

    1986-01-01

    The advent of biomineralization at the turn of the Precambrian/Cambrian boundary has been a major event in the Earth's evolutionary history. With this there has been a major shift from abiotic to biotic formation of minerals such as phosphates and carbonates and, subsequently, silica. The dominant factor which effected this shift is a change in ocean's chemistry with respect to its Ca 2+ and mineral nutrient contents. Mechanism controlling the biotic mineral formation is different from that controlling the abiotic one in that the former is enzymically controlled. It is suggested that this difference is also manifested in the stable carbon isotope fractionation between the two processes and has implication for the interpretation of stable carbon isotope record. (Author)

  5. Increase in soil stable carbon isotope ratio relates to loss of organic carbon: results from five long-term bare fallow experiments.

    Science.gov (United States)

    Menichetti, Lorenzo; Houot, Sabine; van Oort, Folkert; Kätterer, Thomas; Christensen, Bent T; Chenu, Claire; Barré, Pierre; Vasilyeva, Nadezda A; Ekblad, Alf

    2015-03-01

    Changes in the (12)C/(13)C ratio (expressed as δ(13)C) of soil organic C (SOC) has been observed over long time scales and with depth in soil profiles. The changes are ascribed to the different reaction kinetics of (12)C and (13)C isotopes and the different isotopic composition of various SOC pool components. However, experimental verification of the subtle isotopic shifts associated with SOC turnover under field conditions is scarce. We determined δ(13)C and SOC in soil sampled during 1929-2009 in the Ap-horizon of five European long-term bare fallow experiments kept without C inputs for 27-80 years and covering a latitudinal range of 11°. The bare fallow soils lost 33-65% of their initial SOC content and showed a mean annual δ(13)C increase of 0.008-0.024‰. The (13)C enrichment could be related empirically to SOC losses by a Rayleigh distillation equation. A more complex mechanistic relationship was also examined. The overall estimate of the fractionation coefficient (ε) was -1.2 ± 0.3‰. This coefficient represents an important input to studies of long-term SOC dynamics in agricultural soils that are based on variations in (13)C natural abundance. The variance of ε may be ascribed to site characteristics not disclosed in our study, but the very similar kinetics measured across our five experimental sites suggest that overall site-specific factors (including climate) had a marginal influence and that it may be possible to isolate a general mechanism causing the enrichment, although pre-fallow land use may have some impact on isotope abundance and fractionation.

  6. Stable isotope signatures of gases liberated from fluid inclusions in bedrock at Olkiluoto

    International Nuclear Information System (INIS)

    Eichinger, F.; Meier, D.; Haemmerli, J.; Diamond, L.

    2010-12-01

    Fluid inclusions in quartzes of the Olkiluoto bedrock contain gaseous N 2 , CO 2 , H 2 , CH 4 , and higher hydrocarbons in varying proportions. Stable carbon and hydrogen isotope signatures of the gas phases give valuable information on their origin and the formation conditions. In previous studies, a method to liberate and quantify the gases trapped in fluid inclusions was developed. It allowed determining the carbon isotope signatures of liberated CO 2 , CH 4 and higher hydrocarbons (HHC), but no hydrogen isotope data were acquired. The method was advanced and, in this study, also stable hydrogen isotopes of CH 4 and H 2 liberated from fluid inclusions could be analysed. The stable carbon signatures of methane and higher hydrocarbons, as well as the hydrogen isotope signatures of methane indicate a predominant thermogenic provenance for those gases. (orig.)

  7. Water vapor stable isotope observations from tropical Australia

    KAUST Repository

    Parkes, Stephen

    2015-04-01

    The response of the tropical hydrological cycle to anthropogenically induced changes in radiative forcing is one of the largest discrepancies between climate models. Paleoclimate archives of the stable isotopic composition of precipitation in the tropics indicate a relationship with precipitation amount that could be exploited to study past hydroclimate and improve our knowledge of how this region responds to changes in climate forcing. Recently modelling studies of convective parameterizations fitted with water isotopes and remote sensing of water vapor isotopes in the tropics have illustrated uncertainty in the assumed relationship with rainfall amount. Therefore there is a need to collect water isotope data in the tropics that can be used to evaluate these models and help identify the relationships between the isotopic composition of meteoric waters and rainfall intensity. However, data in this region is almost non-existent. Here we present in-situ water vapor isotopic measurements and the HDO retrievals from the co-located Total Column Carbon Observing Network (TCCON) site at Darwin in Tropical Australia. The Darwin site is interestingly placed within the tropical western pacific region and is impacted upon by a clear monsoonal climate, and key climate cycles including ENSO and Madden Julian Oscillations. The analysis of the data illustrated relationships between water vapor isotopes and humidity which demonstrated the role of precipitation processes in the wet season and air mass mixing during the dry season. Further the wet season observations show complex relationships between humidity and isotopes. A simple Rayleigh distillation model was not obeyed, instead the importance of rainfall re-evaporation in generating the highly depleted signatures was demonstrated. These data potentially provide a useful tool for evaluating model parameterizations in monsoonal regions as they demonstrate relationships with precipitation processes that cannot be observed with

  8. Stable isotopes as tracers for radionuclides

    International Nuclear Information System (INIS)

    Giussani, A.; Bartolo, D. de; Cantone, M.C.; Zilker, T.; Greim, H.; Roth, P.; Werner, E.

    2000-01-01

    The assessment of internal dose after incorporation of radionuclides requires as input data the knowledge of the uptake into the systemic circulation, the distribution and retention in selected organs, the excretion pathways. Realistic biokinetic models are needed for reliable estimates, correct interpretation of bioassay measurements, appropriate decision-making in radiological emergencies. For many radionuclides, however, the biokinetic models currently recommended are often generic, with very few specific parameters, due to the lack of experimental human data. The use of stable isotopes as tracers enables to determine important biokinetic parameters such as the fractional uptake, the clearance from the transfer compartment, the excretion patterns under experimentally controlled conditions. The subjects investigated are not exposed to any radiation risk, so this technique enables to obtain biokinetic information also for sensitive groups of the population, such as children or pregnant women, and to determine age- and gender-specific model parameters. Sophisticated analytical method, able to discriminate and quantitate different isotopes of the same element in complex matrices such as biological fluids, have to be purposely developed and optimized. Activation analysis and mass spectrometry are the most proper techniques of choice. Experiments were conducted with molybdenum, tellurium, ruthenium and zirconium. Activation analysis with protons, thermal ionization mass spectrometry and inductively coupled mass spectrometry were employed for the determination of stable isotopes of these elements in blood plasma and urine samples. Several deviations from the predictions of the ICRP models were observed. For example, modifications to the current model for molybdenum have been suggested on the basis of these results. The dose coefficients to the target regions calculated with this proposed model are even of one order of magnitude different than the ICRP estimates

  9. Carbon transfer from photosynthesis to below ground fine root/hyphae respiration in Quercus serrata using stable carbon isotope pulse labeling

    Science.gov (United States)

    Dannoura, M.; Kominami, Y.; Takanashi, S.; Takahashi, K.

    2013-12-01

    Studying carbon allocation in trees is a key to better understand belowground carbon cycle and its response to climate change. Tracing 13C in tree and soil compartments after pulse labeling is one of powerful tool to study the fate of carbon in forest ecosystems. This experiment was conducted in Yamashiro experimental forest, Kyoto, Japan. Annual mean temperature and precipitation from 1994 to 2009 are 15.5 ° C and 1,388 mm respectively. The branch pulse labeling were done 7 times in 2011 using same branch of Quercus serrata (H:11.7 m, DBH; 33.7 cm) to see seasonal variations of carbon velocity. Whole crown labeling of Quercus serrata (H:9 m, DBH; 13.7 cm) was done in 2012 to study carbon allocation and to especially focus on belowground carbon flux until to the hyphae respiration. Pure 13CO2 (99.9%) was injected to the labeling chamber which was set to branch or crown. Then, after one hour of branch labeling and 3.5 hour for crown labeling, the chamber was opened. Trunk respiration chambers, fine root chambers and hyphae chambers were set to the target tree to trace labeled carbon in the CO2 efflux. 41 μm mesh was used to exclude ingrowth of roots into hyphae chambers. The results show that the velocity of carbon through the tree varied seasonally, with higher velocity in summer than autumn, averaging 0.47 m h-1. Half-lives of labeled carbon in autotrophic respiration were similar above and below ground during the growing season, but they were twice longer in trunk than in root in autumn. From the whole crown labeling done end of growing season, the 13CO2 signal was observed 25 hours after labeling in trunk chamber and 34-37.7 hours after labeling in fine root and hyphae respiration almost simultaneously. Half-lives of 13 was longer in trunk than below ground. Trunk respiration was still using labelled carbon during winter suggesting that winter trunk respiration is partly fueled by carbon stored in the trunk at the end of the growing season.

  10. Climate history of the Tibetan Plateau for the last 1500 years as inferred from stable carbon isotopes in three-rings

    International Nuclear Information System (INIS)

    Helle, G.; Schleser, G.H.; Braeuning, A.

    2002-01-01

    For the south-eastern part of Tibet, i.e. Qamdo, a carbon isotope chronology from spruce and juniper trees, covering the last 400 and 1600 years, respectively, has been developed. Juniper tree-rings were sampled in pentad blocks, whereas the spruce chronology is annually resolved in order enable appropriate calibration of isotope data with the short instrumental temperature record available. The chronology shows a number of different climatic phases which have their analogues in Europe and North America. A short warm phase between 1200 and 1300AD appears to correspond to the Mediaeval Warm Period and a larger cool phase from about 1450 to 1600AD appears to correspond to the Little Ice Age with a short recurring episode around 1850. The current results suggest that the observed events may have occurred over the entire Northern Hemisphere, though they do not seem to have been contemporaneous with Europe and North America. (author)

  11. Stable Isotope Systematics of Coalbed Gas during Desorption and Production

    Directory of Open Access Journals (Sweden)

    Martin Niemann

    2017-06-01

    Full Text Available The stable carbon isotope ratios of coalbed methane (CBM demonstrate diagnostic changes that systematically vary with production and desorption times. These shifts can provide decisive, predictive information on the behaviour and potential performance of CBM operations. Samples from producing CBM wells show a general depletion in 13C-methane with increasing production times and corresponding shifts in δ13C-CH4 up to 35.8‰. Samples from canister desorption experiments show mostly enrichment in 13C for methane with increasing desorption time and isotope shifts of up to 43.4‰. Also, 13C-depletion was observed in some samples with isotope shifts of up to 32.1‰. Overall, the magnitudes of the observed isotope shifts vary considerably between different sample sets, but also within samples from the same source. The δ13C-CH4 values do not have the anticipated signature of methane generated from coal. This indicates that secondary processes, including desorption and diffusion, can influence the values. It is also challenging to deconvolute these various secondary processes because their molecular and isotope effects can have similar directions and/or magnitudes. In some instances, significant alteration of CBM gases has to be considered as a combination of secondary alteration effects.

  12. Stable isotopes of bulk organic matter to trace carbon and nitrogen dynamics in an estuarine ecosystem in Babitonga Bay (Santa Catarina, Brazil)

    International Nuclear Information System (INIS)

    Barros, Grace Virginia; Martinelli, Luiz Antonio; Oliveira Novais, Therezinha M.; Ometto, Jean Pierre H.B.; Zuppi, Gian Maria

    2010-01-01

    The biogeochemical processes affecting the transport and cycling of terrestrial organic carbon in coastal and transition areas are still not fully understood. One means of distinguishing between the sources of organic materials contributing to particulate organic matter (POM) in Babitonga Bay waters and sediments is by the direct measurement of δ 13 C of dissolved inorganic carbon (DIC) and δ 13 C and δ 15 N in the organic constituents. An isotopic survey was taken from samples collected in the Bay in late spring of 2004. The results indicate that the δ 13 C and δ 15 N compositions of OM varied from - 21.7 per mille to - 26.2 per mille and from + 9.2 per mille to - 0.1 per mille , respectively. δ 13 C from DIC ranges from + 0.04 per mille to - 12.7 per mille . The difference in the isotope compositions enables the determination of three distinct end-members: terrestrial, marine and urban. Moreover, the evaluation of source contribution to the particulate organic matter (POM) in the Bay, enables assessment of the anthropogenic impact. Comparing the depleted values of δ 13 C DIC and δ 13 C POC it is possible to further understand the carbon dynamic within Babitonga Bay.

  13. A theory of stable-isotope dilution mass spectrometry

    International Nuclear Information System (INIS)

    Pickup, J.F.; McPherson, C.K.

    1977-01-01

    In order to perform quantitative analysis using stable isotope dilution with mass spectrometry, an equation is derived which describes the relationship between the relative proportions of natural and labelled material and measured isotope ratios

  14. Carbon Isotope Chemostratigraphy, the Baby and the Bathwater

    Science.gov (United States)

    Arthur, M. A.

    2008-12-01

    Secular variations in the carbon isotopic values of carbonate sediments and rocks and their individual components have been applied successfully to problems of stratigraphic correlation and for interpretation of past changes in the global carbon cycle. However, this methodology is not without problems. A major tenet of stable isotope chemostratigraphy involves sampling and analyzing multiple, widely separated sequences, and, if possible, multiple carbon-bearing components (e.g., carbonate and organic carbon) in order to demonstrate a global signal. In some cases, this methodology has been short-circuited in the zeal to reveal a new event or excursion, particularly for time intervals for which adequate sequences are somewhat rare. Likewise, although most carbonate researchers are quite aware of the possible importance of diagenesis, particularly in organic-carbon rich sequences or in shoal-water carbonate sequences with longer-term subaerial exposure events, such overprints commonly go unrecognized or are considered of minor impact. Studies of stable isotope variations in carbonate sequences should always employ textural and geochemical methodologies for detecting and even quantifying diagenesis, if possible. Although some diagenetically overprinted or misinterpreted geochemical data have undoubtedly appeared in the literature, there are many excellent examples of global carbon isotope variations in records expressed in pelagic biogenic carbonate, marine organic carbon, platform carbonates, and terrestrial organic matter. Arguably, one of the best-documented examples is the Cenomanian-Turonian (ca. 93 Ma) positive carbon isotope excursion. The amplitude of the Cenomanian-Turonian carbon isotope excursion is similar among all types of records, but there are subtle pattern differences that arise from differences in sedimentation rate among and within sequences. Organic carbon and carbonate carbon isotope signals also may differ in phasing and amplitude for certain

  15. Stable carbon isotopic composition of petroleum condensate from the nile Delta and western Sinai fields and its correlation with crude oils and natural gases

    International Nuclear Information System (INIS)

    Abd El Samie, S.G.

    2006-01-01

    Twenty six of condensate samples from three provinces; Abu Madi (onshore NE Delta), Port Fouad (offshore) in the Mediterranean sea, and Abu Rudeis areas, were analyzed and correlated to the Nile Delta, Gulf of Suez and western desert crude oils. Different isotopic results were obtained specifying each group that reflects the depositional environment, temperature gradient and maturation level of organic matter in each area. The mean isotopic results (av. σ 13 C) of Abu Madi condensate samples reached about -26.41 close to the values of the western desert total oil, indicating thermal graded fluid and depositional environment very close to the western desert in hydrocarbon type (mainly of terrestrial sources), thermal condition and long time of deposition. The offshore Port Fouad condensate samples have relatively wide range of σ 13 C between -27.24 to -24.03% representing mixing between marine and terrestrial hydrocarbons migrated from the near shore areas of the Nile Delta to the Mediterranean sea sub-basins. Abu Rudeis condensate samples have the isotopic signature of σ 13 C = -30.09 to -29.05% close to the Gulf of Suez crude oil samples which reflect the deposition under mainly marine environment of the Red Sea basins. As petroleum condensates considered as moderate compounds between oils and gases, their isotopic contents refer to the produced oil or gas from the same sample. Though condensate samples are correlated with gases produced from the Nile Delta. Based on carbon isotopic values of methane and light gas fractions, the produced gases from the Nile Delta could be generated mainly from terrestrial sources enriched in σ 13 C of C 2 +. These gases are classified according to the thermogenic origin enriched in σ 13 C C H4 in the Nile Delta onshore fields in Abu Madi formation. In shallower formations (Kafr El Sheikh formation), isotopically light gases were found in the NE direction and appeared to be of biogenic source, whereas mixed gases were found in

  16. [Fractionation of hydrogen stable isotopes in the human body].

    Science.gov (United States)

    Siniak, Iu E; Grigor'ev, A I; Skuratov, V M; Ivanova, S M; Pokrovskiĭ, B G

    2006-01-01

    Fractionation of hydrogen stable isotopes was studied in 9 human subjects in a chamber with normal air pressure imitating a space cabin. Mass-spectrometry of isotopes in blood, urine, saliva, and potable water evidenced increases in the contents of heavy H isotope (deuterium) in the body liquids as compared with water. These results support one of the theories according to which the human organism eliminates heavy stable isotopes of biogenous chemical elements.

  17. Intra-specific diet shift in manila clams (Ruditapes philippinarum) as revealed by carbon and nitrogen stable isotopes and fatty acid biomarker

    Science.gov (United States)

    Suh, Y.; Shin, K.

    2011-12-01

    Manila clams sampled in Seonjae Island, Korea with shell lengths (SL) below 19.76 mm in average showed a significantly depleted carbon and nitrogen isotope values (Pcultured in IFHRI. The result of fatty acid composition of manila clams in relation to size or growth rate suggests that fast growing clams would have rapid metabolism of fatty acids not required by the animals and an accumulation of the essential fatty acids (PUFA). In addition, their higher energy requirement and more active state of development would further diminish lipid reserve of the species.

  18. Tellurium Stable Isotopes as a Paleoredox Proxy

    Science.gov (United States)

    Wasserman, N.; Johnson, T. M.

    2017-12-01

    Despite arguments for variably-oxygenated shallow waters and anoxic deep marine waters, which delayed animal development until the Neoproterozoic Oxidation Event, the magnitude of atmospheric oxygen during the Proterozoic is still uncertain [1]. The evidence for low pO2 (<0.1-1% PAL) is based on geochemical and isotopic proxies, which track the mobilization of Fe and Mn on the continents. For example, large chromium isotope shifts occur at the Neoproterozoic Oxidation Event due to the initiation of Cr redox cycling, but this proxy is insensitive to fluctuations in the lower-pO2 conditions at other times during the Proterozoic. Tellurium, a metalloid with a lower threshold to oxidation, may be sensitive to pO2 shifts in a lower range. In the reduced forms, Te(-II) and Te(0), the element is insoluble and immobile. However, in the more oxidized phases, Te(IV) and Te(VI), Te can form soluble oxyanions (though it tends to adsorb to Fe-oxyhydroxides and clays) [2]. Te stable isotopes have been shown to fractionate during abiotic or biologic reduction of Te(VI) or Te(IV) to elemental Te(0) [3, 4]. Utilizing hydride generation MC-ICP-MS, we are able to obtain high precision (2σ 0.04‰) measurements of δ128Te/125Te for natural samples containing < 10 ng of Te. A suite of Phanerozoic and Proterozoic ironstones show significant variation in δ128Te/125Te (<0.5‰), suggesting that the Te redox cycle was active during the Proterozoic. Future directions will include Te isotope measurements of Precambrian paleosols to determine natural isotope variation before the Great Oxidation Event and experiments to determine fractionation during adsorption to Fe-oxyhydroxides. [1] Planavsky et al. (2014) Science 346 (6209), pp. 635-638 [2] Qin et al. (2017) Environmental Science and Technology 51 (11), pp 6027-6035 [3] Baesman et al. (2007) Applied Environmental Microbiology 73 (7), pp 2135-2143 [4] Smithers and Krause (1968) Canadian Journal of Chemistry 46(4): pp 583-591

  19. Carbon isotopes in mollusk shell carbonates

    Science.gov (United States)

    McConnaughey, Ted A.; Gillikin, David Paul

    2008-10-01

    Mollusk shells contain many isotopic clues about calcification physiology and environmental conditions at the time of shell formation. In this review, we use both published and unpublished data to discuss carbon isotopes in both bivalve and gastropod shell carbonates. Land snails construct their shells mainly from respired CO2, and shell δ13C reflects the local mix of C3 and C4 plants consumed. Shell δ13C is typically >10‰ heavier than diet, probably because respiratory gas exchange discards CO2, and retains the isotopically heavier HCO3 -. Respired CO2 contributes less to the shells of aquatic mollusks, because CO2/O2 ratios are usually higher in water than in air, leading to more replacement of respired CO2 by environmental CO2. Fluid exchange with the environment also brings additional dissolved inorganic carbon (DIC) into the calcification site. Shell δ13C is typically a few ‰ lower than ambient DIC, and often decreases with age. Shell δ13C retains clues about processes such as ecosystem metabolism and estuarine mixing. Ca2+ ATPase-based models of calcification physiology developed for corals and algae likely apply to mollusks, too, but lower pH and carbonic anhydrase at the calcification site probably suppress kinetic isotope effects. Carbon isotopes in biogenic carbonates are clearly complex, but cautious interpretation can provide a wealth of information, especially after vital effects are better understood.

  20. Geographic variation of stable isotopes in African elephant ivory

    Science.gov (United States)

    Ziegler, S.; Merker, S.; Jacob, D.

    2012-04-01

    In 1989, the international community listed the African elephant in Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) thus prohibiting commercial ivory trade. Recent surveillance data show that the illegal trade in ivory has been growing worldwide. Long-term preservation of many of the African elephant populations can be supported with a control mechanism that helps with the implementation of remedial conservation action. Therefore, setting up a reference database that predicts the origin of ivory specimens can assist in determining smuggling routes and the provenance of illegal ivory. Our research builds on earlier work to seek an appropriate method for determining the area of origin for individual tusks. Several researchers have shown that the provenance of elephant ivory can be traced by its isotopic composition, but this is the first attempt to produce an integrated isotopic reference database of elephant ivory provenance. We applied a combination of various routine geochemical analyses to measure the stable isotope ratios of hydrogen, carbon, nitrogen, oxygen, and sulphur. Up to now, we analysed 606 ivory samples of known geographical origin from African range states, museums and private collections, comprising 22 African elephant range states. The isotopic measurements were superimposed with data layers from vegetation, geology and climate. A regression function for the isotope composition of the water isotopes in precipitation and collagen in ivory was developed to overcome the problem of imprecise origin of some of the sampled material. Multivariate statistics, such as nearest neighborhood and discriminate analysis were applied to eventually allow a statistical determination of the provenance for ivory of unknown origin. Our results suggest that the combination of isotopic parameters have the potential to provide predictable and complementary markers for estimating the origin of seized elephant ivory.

  1. Applications of stable Isotope ratios determinations in fruit juice authentication

    International Nuclear Information System (INIS)

    Magdas, Dana Alina; Dehelean, Adriana; Voica, Cezara; Puscas, Romulus

    2010-01-01

    Full text: Adulteration of a product consists in making it impure by fraudulent addition of a foreign or inferior substance. The result is either an alteration of the product and of its quality or a falsification. The falsification is a voluntary act with the intention of abuse. The falsification may be more or less sophisticated and its sophistication as well as its costs increases with the improvement of analytical methods. Vacuum concentration with aroma does not affect the chemical composition of fruit juices and therefore the determination of deuterium (D) and oxygen-18 content in waters is the most confident procedure for differentiating between a natural single strength juice and a juice rediluted from a concentrate. This technique is based on the fact that when absorbed by a plant, the rainwater or the irrigation water is fractionated by evapotranspiration, and enriched in the heavy isotopes (deuterium and oxygen-18) with respect to the light isotope (hydrogen and oxygen-16, respectively). It is known that climatic conditions affect the isotope content of rain waters and therefore that of fruit juices waters: the warmer climate, the higher the deuterium and oxygen-18 contents in water. Rainwater and tap water have nearly the same isotopic content and the water of fruit juices derived from concentrate by dilution with tap water has an isotopic content close to that of tap water. This makes it easy to distinguish diluted concentrates from the isotopically more enriched water of authentic single strength juice. In this study, single strength juice, in Romanian fruits, were investigated by mean of stable isotope measurements (oxygen, hydrogen and carbon) in order to offer a discussion basis for the authenticity of some fruit juices currently available on Romanian market. (authors)

  2. Stable isotope sales; Mound Facility customer and shipment summaries, FY 1977

    International Nuclear Information System (INIS)

    Ruwe, A.H. Jr.

    1978-01-01

    A listing is given of Mound Facility's sales of stable isotopes of noble gases, carbon, oxygen, nitrogen, chlorine, and sulfur for Fiscal Year 1977. Purchasers are listed alphabeticaly and are divided into domestic and foreign groups. A cross-reference index by location is included for domestic customers. Cross-reference listings by isotope purchased are included for all customers

  3. Stable isotope sales: Mound Laboratory customer and shipment summaries, FY-1975

    International Nuclear Information System (INIS)

    Eck, C.F.

    1976-01-01

    A listing is given of Mound Laboratory's sales of stable isotopes of noble gases, carbon, oxygen, nitrogen, and sulfur for Fiscal Year 1975. Purchasers are listed alphabetically and are divided into domestic and foreign groups. A cross reference index by location is included for domestic customers. Cross reference listings by isotope purchased are included for all customers

  4. Stable isotope sales: Mound Facility customer and shipment summaries, FY 1981

    International Nuclear Information System (INIS)

    Ruwe, A.H. Jr.

    1982-01-01

    A listing is given of Mound Facility's sales of stable isotopes of noble gases, carbon, oxygen, nitrogen, chlorine, and sulfur for Fiscal Year 1981. Purchasers are listed alphabetically and are divided into domestic and foreign groups. A cross-reference index by location is included for domestic customers. Cross-reference listings by isotope purchased are included for all customers

  5. Applications of stable isotope analysis in mammalian ecology.

    Science.gov (United States)

    Walter, W David; Kurle, Carolyn M; Hopkins, John B

    2014-01-01

    In this editorial, we provide a brief introduction and summarize the 10 research articles included in this Special Issue on Applications of stable isotope analysis in mammalian ecology. The first three articles report correction and discrimination factors that can be used to more accurately estimate the diets of extinct and extant mammals using stable isotope analysis. The remaining seven applied research articles use stable isotope analysis to address a variety of wildlife conservation and management questions from the oceans to the mountains.

  6. Stable isotope customer list and summary of shipments: FY 1975

    International Nuclear Information System (INIS)

    Davis, W.C.

    1975-10-01

    This compilation is published as an aid to those concerned with the separation and sale of stable isotopes. The information is divided into four sections: an alphabetical list of domestic and foreign customers, showing the stable isotopes purchased during the fiscal year; an alphabetical list of isotopes, cross-referenced to customer numbers and divided into domestic and foreign categories; an alphabetical list of states and countries, cross-referenced to customer numbers and indicating geographical concentrations of isotope users; and a tabulation of the shipments, quantities, and dollars for domestic, foreign, and project categories for each isotope, with the totals for loaned isotopes shown at the end of the table. (auth)

  7. STABLE ISOTOPE GEOCHEMISTRY OF MASSIVE ICE

    Directory of Open Access Journals (Sweden)

    Yurij K. Vasil’chuk

    2016-01-01

    Full Text Available The paper summarises stable-isotope research on massive ice in the Russian and North American Arctic, and includes the latest understanding of massive-ice formation. A new classification of massive-ice complexes is proposed, encompassing the range and variabilityof massive ice. It distinguishes two new categories of massive-ice complexes: homogeneousmassive-ice complexes have a similar structure, properties and genesis throughout, whereasheterogeneous massive-ice complexes vary spatially (in their structure and properties andgenetically within a locality and consist of two or more homogeneous massive-ice bodies.Analysis of pollen and spores in massive ice from Subarctic regions and from ice and snow cover of Arctic ice caps assists with interpretation of the origin of massive ice. Radiocarbon ages of massive ice and host sediments are considered together with isotope values of heavy oxygen and deuterium from massive ice plotted at a uniform scale in order to assist interpretation and correlation of the ice.

  8. Stable isotopic variation in tropical forest plants for applications in primatology.

    Science.gov (United States)

    Blumenthal, Scott A; Rothman, Jessica M; Chritz, Kendra L; Cerling, Thure E

    2016-10-01

    Stable isotope analysis is a promising tool for investigating primate ecology although nuanced ecological applications remain challenging, in part due to the complex nature of isotopic variability in plant-animal systems. The aim of this study is to investigate sources of carbon and nitrogen isotopic variation at the base of primate food webs that reflect aspects of primate ecology. The majority of primates inhabit tropical forest ecosystems, which are dominated by C3 vegetation. We used stable isotope ratios in plants from Kibale National Park, Uganda, a well-studied closed-canopy tropical forest, to investigate sources of isotopic variation among C3 plants related to canopy stratification, leaf age, and plant part. Unpredictably, our results demonstrate that vertical stratification within the canopy does not explain carbon or nitrogen isotopic variation in leaves. Leaf age can be a significant source of isotopic variation, although the direction and magnitude of this difference is not consistent across tree species. Some plant parts are clearly differentiated in carbon and nitrogen isotopic composition, particularly leaves compared to non-photosynthetic parts such as reproductive parts and woody stem parts. Overall, variation in the isotopic composition of floral communities, plant species, and plant parts demonstrates that stable isotope studies must include analysis of local plant species and parts consumed by the primates under study from within the study area. Am. J. Primatol. 78:1041-1054, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  9. Petrologic and stable isotopic studies of a fossil hydrothermal system in ultramafic environment (Chenaillet ophicalcites, Western Alps, France): Processes of carbonate cementation

    Science.gov (United States)

    Lafay, Romain; Baumgartner, Lukas P.; Stephane, Schwartz; Suzanne, Picazo; German, Montes-Hernandez; Torsten, Vennemann

    2017-12-01

    The Late Jurassic Chenaillet ophiolitic complex (Western Alps) represents parts of an oceanic core-complex of the Liguria-Piemonte domain. A model for the origin and evolution of the Chenaillet ophicalcites based on textural and isotopic characterization is presented. The Chenaillet ophicalcites correspond to brecciated serpentinized peridotites that record seafloor shallow serpentinization at a minimum temperatures of 150 °C followed by authigenic carbonation. Carbonation starts with a network of micrometric to millimetric pre- or syn-clast formation calcite veins accompanied by a pervasive carbonation of residual olivine and serpentine inside the serpentinite mesh core. A matrix of small calcite (values that range between - 5‰ and + 0.4‰. The lower values were obtained for calcite within the serpentinite clasts. The δ18O (VSMOW) values have a range between + 11‰ and + 16‰ in carbonated clasts. The δ18O values in the matrix are fairly homogeneous with an average at + 12‰ and the late calcite veins have values between + 12.5 and + 15.5‰. These values suggest a relatively high temperature of formation for all the carbonates. Carbonates within clast are mainly characterized by a formation temperature in the range of 110 °C to 180 °C assuming a δ18O value of seawater of 0‰, the matrix forms at a temperature of ca. 165 °C. Late veins are characterized by a formation temperature ranging between 120and 155 °C. We propose a model where serpentinization is followed by discrete carbonation then brecciation and cementation as a consequence of continuous hydrothermal fluid circulation in the serpentinite basement. This is comparable to observations made in the stockwork of present-day long-lived oceanic hydrothermal systems.

  10. A seasonal and spatial comparison of metals, and stable carbon and nitrogen isotopes, in Chincoteague Bay and the marsh deposits of Assateague Island and the adjacent vicinity, Maryland and Virginia

    Science.gov (United States)

    Ellis, Alisha M.; Smith, Christopher G.

    2017-11-28

    After Hurricane Sandy, scientists from the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center conducted a seasonal collection of estuarine, marsh, and sandy overwash surface sediments from Chincoteague Bay, Tom’s Cove, and the surrounding Assateague Island and Delmarva Peninsula in March–April and October 2014. Surplus surface sediment was analyzed for metals, percent carbon and nitrogen, δ13C, and δ15N as part of a complementary U.S. Geological Survey Coastal and Marine Geology Program Sea-level and Storm Impacts on Estuarine Environments and Shorelines project study. The geochemical subsample analyzed for metals and stable isotopes at each site may be used for comparison with past data sets, to create a modern baseline of the natural distribution of the area, to understand seasonal variability as it relates to the health of the local environment, and to assess marsh-to-bay interactions. The use of metals, stable carbon, and stable nitrogen isotopes allows for a more cohesive snapshot of factors influencing the environment and could aid in tracking environmental change.This report serves as an archive for chemical data derived from the surface sediment. Data are available for a seasonal comparison between the March–April 2014 and October 2014 sampling trips. Downloadable data are available as Microsoft Excel spreadsheets. These additional files include formal Federal Geographic Data Committee metadata (data downloads).

  11. Carbon stable isotope composition of charophyte organic matter in a small and shallow Spanish water body as a baseline for future trophic studies

    Directory of Open Access Journals (Sweden)

    María Antonia Rodrigo

    2015-12-01

    Full Text Available Quantitative descriptions of foodweb structure based on isotope niche space require knowledge of producers’ isotopic signatures. In freshwater ecosystems charophytes are one of the main components of submerged vegetation and the feeding base for many herbivorous consumers, but knowledge about their organic carbon isotopic signatures is sparse. In this study, the δ13C organic values (and organic %C and %N of the four species of submerged macrophytes (three charophytes - Chara hispida, Nitella hyalina and Tolypella glomerata - and one angiosperm, Myriophyllum spicatum growing in a newly created shallow pond were measured monthly over a period of one year, to discern if i all charophyte species susceptible to being food for consumers and growing in the same waterbody have the same C isotopic composition; ii the δ13C values of a charophyte species change on a seasonal and spatial scale; iii the different parts (apical nodes, internodes, rhizoids, reproductive organs, oospores of a charophyte species have the same isotopic composition. The δ13C, %C and %N values of organic matter in the sediments where the plants were rooted were also measured as well as several limnological variables. The δ13C values for the angiosperm (-13.7±0.7‰ indicated 13C-enrichment, whereas the N. hyalina δ13C values were the most negative (-22.4±0.7‰. The mean δ13C value for C. hispida was -19.0±1.0‰ and -20.7±0.8‰ for T. glomerata. C. hispida δ13C values had a significant seasonal variation with 13C-poor values in the cold season, and slight spatial differences. Statistically significant differences were found between charophyte rhizoids (13C-enriched and the other parts of the thalli. The δ13C values in the sediments varied throughout time (-13‰ to -26‰. The C content was lower in the charophytes than in the angiosperm and there were no large differences among the charophytes. Charophyte fructifications were enriched in organic C compared to the

  12. Intermediate and deep water mass distribution in the Pacific during the Last Glacial Maximum inferred from oxygen and carbon stable isotopes

    Science.gov (United States)

    Herguera, J. C.; Herbert, T.; Kashgarian, M.; Charles, C.

    2010-05-01

    Intermediate ocean circulation changes during the last Glacial Maximum (LGM) in the North Pacific have been linked with Northern Hemisphere climate through air-sea interactions, although the extent and the source of the variability of the processes forcing these changes are still not well resolved. The ventilated volumes and ages in the upper wind driven layer are related to the wind stress curl and surface buoyancy fluxes at mid to high latitudes in the North Pacific. In contrast, the deeper thermohaline layers are more effectively ventilated by direct atmosphere-sea exchange during convective formation of Subantarctic Mode Waters (SAMW) and Antarctic Intermediate Waters (AAIW) in the Southern Ocean, the precursors of Pacific Intermediate Waters (PIW) in the North Pacific. Results reported here show a fundamental change in the carbon isotopic gradient between intermediate and deep waters during the LGM in the eastern North Pacific indicating a deepening of nutrient and carbon rich waters. These observations suggest changes in the source and nature of intermediate waters of Southern Ocean origin that feed PIW and enhanced ventilation processes in the North Pacific, further affecting paleoproductivity and export patters in this basin. Furthermore, oxygen isotopic results indicate these changes may have been accomplished in part by changes in circulation affecting the intermediate depths during the LGM.

  13. Stable isotope ratios in hair and teeth reflect biologic rhythms.

    Directory of Open Access Journals (Sweden)

    Otto Appenzeller

    Full Text Available Biologic rhythms give insight into normal physiology and disease. They can be used as biomarkers for neuronal degenerations. We present a diverse data set to show that hair and teeth contain an extended record of biologic rhythms, and that analysis of these tissues could yield signals of neurodegenerations. We examined hair from mummified humans from South America, extinct mammals and modern animals and people, both healthy and diseased, and teeth of hominins. We also monitored heart-rate variability, a measure of a biologic rhythm, in some living subjects and analyzed it using power spectra. The samples were examined to determine variations in stable isotope ratios along the length of the hair and across growth-lines of the enamel in teeth. We found recurring circa-annual periods of slow and fast rhythms in hydrogen isotope ratios in hair and carbon and oxygen isotope ratios in teeth. The power spectra contained slow and fast frequency power, matching, in terms of normalized frequency, the spectra of heart rate variability found in our living subjects. Analysis of the power spectra of hydrogen isotope ratios in hair from a patient with neurodegeneration revealed the same spectral features seen in the patient's heart-rate variability. Our study shows that spectral analysis of stable isotope ratios in readily available tissues such as hair could become a powerful diagnostic tool when effective treatments and neuroprotective drugs for neurodegenerative diseases become available. It also suggests that similar analyses of archaeological specimens could give insight into the physiology of ancient people and animals.

  14. Magnesium stable isotope ecology using mammal tooth enamel

    Science.gov (United States)

    Martin, Jeremy E.; Vance, Derek; Balter, Vincent

    2015-01-01

    Geochemical inferences on ancient diet using bone and enamel apatite rely mainly on carbon isotope ratios (δ13C) and to a lesser extent on strontium/calcium (Sr/Ca) and barium/calcium (Ba/Ca) elemental ratios. Recent developments in nontraditional stable isotopes provide an unprecedented opportunity to use additional paleodietary proxies to disentangle complex diets such as omnivory. Of particular relevance for paleodietary reconstruction are metals present in large quantity in bone and enamel apatite, providing that biologically mediated fractionation processes are constrained. Calcium isotope ratios (δ44Ca) meet these criteria but exhibit complex ecological patterning. Stable magnesium isotope ratios (δ26Mg) also meet these criteria but a comprehensive understanding of its variability awaits new isotopic data. Here, 11 extant mammal species of known ecology from a single locality in equatorial Africa were sampled for tooth enamel and, together with vegetation and feces, analyzed for δ26Mg, δ13C, Sr/Ca, and Ba/Ca ratios. The results demonstrate that δ26Mg incorporated in tooth enamel becomes heavier from strict herbivores to omnivores/faunivores. Using data from experimentally raised sheep, we suggest that this 26Mg enrichment up the trophic chain is due to a 26Mg enrichment in muscle relative to bone. Notably, it is possible to distinguish omnivores from herbivores, using δ26Mg coupled to Ba/Ca ratios. The potential effects of metabolic and dietary changes on the enamel δ26Mg composition remain to be explored but, in the future, multiproxy approaches would permit a substantial refinement of dietary behaviors or enable accurate trophic reconstruction despite specimen-limited sampling, as is often the case for fossil assemblages.

  15. Use of stable isotope techniques in soil organic matter studies

    International Nuclear Information System (INIS)

    Gerzabek, M.H.

    1998-01-01

    Plants differ distinctly in their C-isotopic composition. The largest differences occur between plant species with different photosynthetic pathways. C 3 - and C 4 -plants are differentiated by approximately 1.4% on the δ-scale (approx. -2.7% 13 C versus -1.3% 13 C). Modern elemental analyser - mass spectrometer combinations reach accuracies of at least 0.01% δ 13 C. Therefore, the difference between C 3 and C 4 plants is sufficient to be used for tracer studies. Several investigations of soil organic mater (SOM) turnover under field conditions were undertaken using the fact that the vegetation cover changed between C 3 and C 4 plants. The discrimination between SOM originating from indigenous vegetation (forest, C 3 ) and sugar cane (C 4 ) after 50 years of cropping introducing two SOM compartments of different stability was described. Another example is the change from prairie vegetation (C 4 ) to different C 3 -crops and the evaluation of the carbon origin at or near equilibrium. More recent studies use 15 N-labelled C 4 -plant residues or 13 C-labelled C 3 -plants to elucidate the fate of carbon and nitrogen in soils developed under C 3 -vegetation. Both in situ experiments and laboratory incubations were used to evaluate carbon and nitrogen fluxes from crop residues. Physical fractionation of bulk soil into particle sizes proved to be of advantage to follow short and long-term dynamics of crop residues within SOM. Changes in the natural abundance of 13 C and 15 N within soil profiles can elucidate leaching or mineralization of humic substances. Changes in the natural abundance of stable isotopes are also possible due to the application of organic manures, quantification, however is not easy because of the small isotopic differences between soil and manure carbon and nitrogen. 15 N labelling of soil nitrogen has been widely used in the last two decades to quantify biological nitrogen fixation. Considerable progress has been made due to the isotope dilution

  16. Carbon and oxygen stable isotopes in large herbivore tooth enamel illustrate a mid-Miocene precipitation increase in the interior Pacific Northwest

    Science.gov (United States)

    Drewicz, A.; Kohn, M. J.

    2017-12-01

    The mid-Miocene Climatic Optimum (MMCO; 13.75-16.9 Ma), represents the warmest period in Earth's history during the last 35 Ma, and is distinguished by low ice volume and high ocean water temperatures. The MMCO has been associated with high atmospheric CO2 (pCO2) similar to levels anticipated in the next century. Thus, understanding MMCO climate may help enlighten predictions of future climate change. Here, using new stable oxygen and carbon isotopes of fossil ungulate tooth enamel from before, during, and after the MMCO, we show that high pCO2 corresponds with warm-wet conditions, whereas low pCO2 corresponds with cool-dry conditions. We specifically show that mean annual precipitation (MAP), as inferred from tooth enamel δ13C values and corrected for atmospheric δ13C values (Δ13C), increased with increasing pCO2. Values of Δ13C > 19.5 ‰ in the lower John Day ( 27 Ma) and Mascall ( 15.3 Ma) localities imply relatively high mean annual precipitation (MAP = 550-850 mm/yr). Values of Δ 13C < 18.5 ‰ at 18 Ma and at four levels between 15 and 3 Ma imply low MAP (≤250 mm/yr), similar to modern climate. High MAP values generally correlate with high pCO2 levels, as inferred from marine records, implicating pCO2 as a principal driver of MAP in the Pacific Northwest. A climate oscillation model best explains our δ 13C data, such that warm-wet conditions during high pCO2 events alternated with cool-dry conditions during low pCO2 events on timescales of 100 kyr. The MMCO may have been more dynamic than originally considered, with wet-warm and cool-dry cycles reflecting Milankovitch cycles. High δ18O values in specimens from the John Day (21.8±0.6 ‰ V-SMOW) and Mascall (21.3±0.5 ‰) Formations may reflect lower elevations for the upwind Cascade Range prior to 7 Ma, or its proximity to the coast compared to more inland sites (δ18O = 17.7±0.9 to 19.6±1.1 ‰). Unusually high δ18O values of Dromomeryx sp. from Red Basin (27.4±0.6 ‰) most likely reflect

  17. Stable Isotope (delta OXYGEN-18, Delta Deuterium, Delta CARBON-13) Dendroclimatological Studies in the Waterloo Region of Southern Ontario, Canada, Between AD 1610 and 1990.

    Science.gov (United States)

    Buhay, William Mark

    Oxygen (delta^{18} O), hydrogen (delta^2H) and carbon (delta^{13}C) isotopes were measured in wood cellulose from elm, white pine and maple trees that grew in southwestern Ontario, Canada. The measured oxygen and hydrogen isotopic data were used for model-based reconstructions of delta^{18}{O}_{meteoric water}, mean annual temperature (MAT) and relative humidity for a period, AD 1610 to 1880, that precedes instrumental records of climate. The carbon isotope measurements were compared with the Cellulose Model inferred climate data to reveal additional environmental information. Modifications made to the Cellulose Model focused on the dynamics of oxygen and hydrogen isotopic fractionation in plants during evapotranspiration and photosynthetic assimilation. For instance, kinetic fractionation of ^{18}O was found to be predictable from theoretical considerations of leaf energy balance and boundary layer dynamics. Kinetic fractionation during evapotranspiration is sensitive to the nature of the boundary layer, which is controlled by leaf size and morphology. Generally, plants with small segmented leaves have a lower component of turbidity in the leaf boundary layer, which results in higher kinetic fractionation values, than do plants having large simple leaves and more turbulent boundary layers. Kinetic ^2H enrichment in plant leaf water can also be rationalized in terms of leaf size and morphology when an apparent temperature-dependent isotope effect, acting in opposition to evaporative enrichment, is taken into account. Accounting for this temperature -dependent isotope effect helps to: (1) reconcile hydrogen kinetic fractionation inconsistencies for different leaves; (2) explain a temperature effect previously attributed to variable biochemical fractionation during cellulose synthesis, and; (3) verify hydrogen biochemical effects in plants. This improved characterization of the oxygen and hydrogen isotopic effects in plants, using the modified Cellulose Model, helped

  18. Investigations of the ratios of stable carbon isotopes in atmospheric relevant VOC using simulation and field experiments; Untersuchungen der Verhaeltnisse stabiler Kohlenstoffisotope in atmosphaerisch relevanten VOC in Simulations- und Feldexperimenten

    Energy Technology Data Exchange (ETDEWEB)

    Spahn, Holger

    2010-07-01

    Volatile organic compounds (VOC) play an important role in the regional and global atmospheric chemistry. The author of the contribution under consideration reports on the analysis of the ratios of stable carbon isotopes ({delta}({sup 13}C) analysis) in atmospheric VOCs. At first, the state of the art of this analytical technique is described. For the first time {delta}({sup 13}C) values of different monoterpenes have been determined in the investigation of vegetable emissions at a plant chamber. By means of the oxidation of {beta}-pinene by ozone in an aerosol chamber, the kinetic isotope effect of this reaction was determined. In southern Germany, air samples for the {delta}({sup 13}C) analysis were collected using a zeppelin. This enables a height-resolved measurement of {delta}({sup 13}C) values. Based on these measurements, the average photochemical age for methanol, toluene and p-xylene at different heights was calculated.

  19. The effects of anthropogenic organic matter inputs on stable carbon and nitrogen isotopes in organisms from different trophic levels in a southern Mediterranean coastal area

    International Nuclear Information System (INIS)

    Vizzini, Salvatrice; Mazzola, Antonio

    2006-01-01

    Stable isotope ratios were used to determine the impact of anthropogenically derived organic matter from onshore and offshore fish farming and a sewage outfall on organisms at different trophic levels (primary producers and consumers) on the south-east coast of Sicily (Italy, Mediterranean). Representative macroalgae and consumers were collected in three sampling locations: 'Impact' and two putative 'Controls' sited to the north of the impacted location. While δ 13 C values of both organic matter sources and consumers varied little between locations, δ 15 N spatial variability was higher and δ 15 N was shown to be a good descriptor of organic enrichment and uptake of anthropogenically derived material within coastal food webs. Isotopic data were analysed using a multivariate approach. Organic matter sources and benthic components were more sensitive to pollution than nektobenthic species and revealed that the effects of anthropogenic activities seem to be detectable over a wide area. The study site is characterised by wide waste dispersal, which brings a reduction in impact in the area directly affected by organic matter inputs and enlarges the area of moderate impact

  20. Unit of stable isotopic N15 analysis

    International Nuclear Information System (INIS)

    Cabrera de Bisbal, Evelin; Paredes U, Maria

    1997-01-01

    The continuous and growing demand of crops and cattle for the domestic inhabitants, forces the search of technical solutions in agriculture. One of the solutions able to be covered in a near future it is the escalation of agricultural production in lands already being cultivated, either by means of an intensification of cultivation and / or increasing the unitary yields. In the intensive cropping systems, the crops extract substantial quantities of nutriments that is recovered by means of the application of fertilizers. Due to the lack of resources and to the increase of commercial inputs prices, it has been necessary to pay attention to the analysis and improvement of low inputs cropping systems and to the effective use of resources. Everything has made to establish a concept of plant nutrition focused system, which integrate the sources of nutriments for plants and the production factors of crops in a productive cropping system, to improve the fertility of soils, the agricultural productivity and profitability. This system includes the biggest efficiency of chemical fertilizers as the maximum profit of alternative sources of nutriments, such as organic fertilizers, citrate-phosphate rocks and biological nitrogen fixation. By means of field experiments under different environmental conditions (soils and climate) it can be determined the best combination of fertilizers practice (dose, placement, opportunity and source) for selected cropping systems. The experimentation with fertilizer, marked with stable and radioactive isotopes, provides a direct and express method to obtain conclusive answers to the questions: where, when and how should be applied. The fertilizers marked with N 1 5 have been used to understand the application of marked fertilizer to the cultivations, and the determination of the proportion of crops nutritious element derived from fertilizer. The isotopic techniques offer a fast and reliable mean to obtain information about the distribution of

  1. Lifetime Stable isotopes profiles in whale earplug: assessment of foraging and migrations in the Northern Hemisphere

    Science.gov (United States)

    Mansouri, F.; Crain, D.; Winfield, Z.; Trumble, S.; Usenko, S.

    2017-12-01

    Whale earplugs, historically used for aging, were used to reconstruct lifetime stable isotope profiles for carbon (δ13C) and nitrogen (δ15N) for individual whales by delaminating lamina within the earplug. These stable isotope profile, which provide Continuous lifetime records of feeding, foraging ecology, and migration, were determined for 20 individuals from 4 baleen species including fin, minke, humpback, and blue whales spanning more than a century (1869 - 2014) using stable isotope analysis. Approximately 1 mg tissue from each lamina (n=1200) was analyzed for carbon and nitrogen stable isotope using continuous flow isotope ratio mass spectrometer (CF-IRMS). This research using whale earplugs have combined age estimates with stable isotope measurements to reconstruct lifetime foraging profiles with a 6-month resolution, providing an unprecedented opportunity to assess periods and trends in dietary fluctuations as well as migration between different foraging area which have distinct isotope values. Trends with these profiles suggest long-term changing in migration, while annual variability highlights seasonal fasting and feeding. Isotopic ratios were also used to identify subpopulations of Atlantic fin whales, which enabled us to assign unidentified humpback and minke whales to the Atlantic or Pacific Oceans. This historical archive of data provides us an unprecedented tool to assess long term marine ecosystem and subsequently marine organism transition to alternate foraging area and shed light on the whale's population status in the Northern hemisphere.

  2. Enriching stable isotopes: Alternative use for Urenco technology

    International Nuclear Information System (INIS)

    Rakhorst, H.; de Jong, P.G.T.; Dawson, P.D.

    1996-01-01

    The International Urenco Group utilizes a technologically advanced centrifuge process to enrich uranium in the fissionable isotope 235 U. The group operates plants in the United Kingdom, the Netherlands, and Germany and currently holds a 10% share of the multibillion dollar world enrichment market. In the early 1990s, Urenco embarked on a strategy of building on the company's uniquely advanced centrifuge process and laser isotope separation (LIS) experience to enrich nonradioactive isotopes colloquially known as stable isotopes. This paper summarizes the present status of Urenco's stable isotopes business

  3. Stable isotope geochemistry : definitions, terminology, measurement and some applications

    International Nuclear Information System (INIS)

    Faure, K.

    2005-01-01

    In 1936, Alfred Nier produced the first precise measurement of isotope abundance ratios and his design still remains the basis of stable isotope mass spectrometry. With this gift from the physicists for routine measurement of isotope ratios, earth scientists began to explore the natural variations of isotopes. Thus began a new era in geoscience research with the hydrological cycle and marine palaeoclimatic research being the first topics to be investigated. Stable isotope measurements have been applied to many fundamental problems in geochemistry, petrology and paleoclimatology, as well as related fields in archaeology, anthropology, physical chemistry, biology and forensic sciences. (author). 52 refs., 11 figs., 2 tabs

  4. Stable isotope customer list and summary of shipments: FY 1984

    International Nuclear Information System (INIS)

    Tracy, J.G.

    1984-12-01

    This compilation is published as an aid to those concerned with the separation and sale of stable isotopes. The information is divided into four sections: (1) alphabetical list of domestic and foreign customers, showing the stable isotopes purchased during the fiscal year; (2) alphabetical list of isotopes, cross-referenced to customer numbers and divided into domestic and foreign categories; (3) alphabetical list of states and countries, cross-referenced to customer numbers and indicating geographical concentrations of isotope users; and (4) tabulation of the shipments, quantities, and dollars for domestic, foreign, and project categories for each isotope

  5. Stable isotope customer list and summary of shipments - FY 1983

    International Nuclear Information System (INIS)

    Davis, W.C.

    1983-12-01

    This compilation is published as an aid to those concerned with the separation and sale of stable isotopes. The information is divided into four sections: (1) alphabetical list of domestic and foreign customers, showing the stable isotopes purchased during the fiscal year; (2) alphabetical list of isotopes, cross-referenced to customer numbers and divided into domestic and foreign categories; (3) alphabetical list of states and countries, cross-referenced to customer numbers and indicating geographical concentrations of isotope users; and (4) tabulation of the shipments, quantities, and dollars for domestic, foreign, and project categories for each isotope

  6. Application of stable isotopes in ecological research : it's all elemental

    International Nuclear Information System (INIS)

    Rogers, K.M.

    2005-01-01

    Stable isotopes have been used traditionally in the physical sciences, primarily in geochemistry, sedimentology, and oceanography. Increasingly, however, stable isotopes are also being used in the biological sciences. Application of stable isotopes in ecological studies can provide new and innovative ways of examining a host of topics of fundamental importance to biologists. These topics include, among others, feeding ecology and food webs, nutrient flow and assimilation, habitat use, migration patterns, and distribution and discrimination of species subpopulations. Furthermore, ecological research with isotopes can be applied at many levels (i.e. tissue and organ, whole animal, population, community, and ecosystem). (author). 38 refs., 2 figs

  7. Stable isotope methodology and its application to nutrition and gastroenterology

    International Nuclear Information System (INIS)

    Klein, P.D.; Hachey, D.L.; Wong, W.W.; Abrams, S.A.

    1993-01-01

    This report describes the activities of the Stable Isotope Laboratory in its function as a core resource facility for stable isotope applications in human nutrition research. Three aspects are covered: Training of visitors, assessment of new instrumentation, and development of new methodology. The research achievements of the laboratory are indicated in the publications that appeared during this period. (author). 23 refs

  8. Biomedical applications of mass spectrometry. Clinical uses of stable isotopes

    International Nuclear Information System (INIS)

    Krahmer, U.I.; McCloskey, J.A.

    1978-01-01

    The review covers typical or important examples of stable isotope usage in clinical fields during the period since the last triennial mass spectrometry conference in 1973. Items are included which involve uses of stable isotopes in human or clinically oriented studies, including measurements carried out on materials of human origin. 163 references. (U.K.)

  9. Stable isotope geochemistry. 3. rev. and enl. ed.

    International Nuclear Information System (INIS)

    Hoefs, J.

    1987-01-01

    Stable Isotope Geochemistry is an authoritative book comprising theoretical and experimental principles; surveying important fractionation mechanisms affecting the most important elements; discussing the natural variations of geologically important reservoirs. This updated 3rd edition, with a completely rewritten and extended main part, contains two new chapters on stable isotope composition of mantle material and on changes of the ocean during the geological past. (orig.)

  10. Characterization of phenols biodegradation by compound specific stable isotope analysis

    Science.gov (United States)

    Wei, Xi; Gilevska, Tetyana; Wenzig, Felix; Hans, Richnow; Vogt, Carsten

    2015-04-01

    -cresol degradation and 2.2±0.3‰ for m-cresol degradation, respectively. The carbon isotope fractionation patterns of phenol degradation differed more profoundly. Oxygen-dependent monooxygenation of phenol by A.calcoaceticus as the initial reaction yielded ƐC values of -1.5±0.02‰. In contrast, the anaerobic degradation initiated by ATP-dependent carboxylation performed by Thauera aromatia DSM 6984, produced no detectable fractionation (ƐC 0±0.1‰). D. cetonica showed a slight inverse carbon isotope fractionation (ƐC 0.4±0.1‰). In conclusion, a validated method for compound specific stable isotope analysis was developed for phenolic compounds, and the first data set of carbon enrichment factors upon the biodegradation of phenol and cresols with different activation mechanisms has been obtained in the present study. Carbon isotope fractionation analysis is a potentially powerful tool to monitor phenolic compounds degradation in the environment.

  11. 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

  12. Weaning age in an expanding population: stable carbon and nitrogen isotope analysis of infant feeding practices in the Okhotsk culture (5th-13th centuries AD) in Northern Japan.

    Science.gov (United States)

    Tsutaya, Takumi; Ishida, Hajime; Yoneda, Minoru

    2015-08-01

    The Okhotsk people were sedentary hunter-gatherer-fishers who lived and prospered in Sakhalin, Hokkaido, and the Kurile Islands during the 5th to 13th centuries AD. They expanded rapidly along the northeastern coast of Hokkaido. We reconstructed infant feeding practices of the Moyoro population of the Okhotsk culture in eastern Hokkaido, Japan. Stable isotope ratios in 58 subadult human skeletons were measured. The results suggest that complementary foods with a relatively low carbon isotope ratio were consumed during and after weaning, as observed in ethnographic descriptions of northern human populations such as the Ainu and isotopically suggested in ancient northern hunter-gatherer-fisher populations. Nitrogen isotope ratios of subadults showed that the age at the end of weaning in the Moyoro population was 1.8 (1.4-2.2 in 95% credible interval) years, which is earlier than that in other northern hunter-gatherer-fisher populations. Because weaning age is one of the most important determinants of fertility, a shorter breastfeeding period suggests increased fertility. Furthermore, better nutrition would further promote the population increase, and thus populations of the Okhotsk culture could expand into new regions. These findings are consistent with recent emerging evidence of great contributions of the Okhotsk to the formation of later Ainu populations and culture. © 2015 Wiley Periodicals, Inc.

  13. Stable isotope geochemistry of deep sea cherts

    Energy Technology Data Exchange (ETDEWEB)

    Kolodny, Y; Epstein, S [California Inst. of Tech., Pasadena (USA). Div. of Geological Sciences

    1976-10-01

    Seventy four samples of DSDP (Deep Sea Drilling Project) recovered cherts of Jurassic to Miocene age from varying locations, and 27 samples of on-land exposed cherts were analyzed for the isotopic composition of their oxygen and hydrogen. These studies were accompanied by mineralogical analyses and some isotopic analyses of the coexisting carbonates. delta/sup 18/0 of chert ranges between 27 and 39 parts per thousand relative to SMOW, delta/sup 18/0 of porcellanite - between 30 and 42 parts per thousand. The consistent enrichment of opal-CT in porcellanites in /sup 18/0 with respect to coexisting microcrystalline quartz in chert is probably a reflection of a different temperature (depth) of diagenesis of the two phases. delta/sup 18/0 of deep sea cherts generally decrease with increasing age, indicating an overall cooling of the ocean bottom during the last 150 m.y. A comparison of this trend with that recorded by benthonic foraminifera (Douglas et al., Initial Reports of the Deep Sea Drilling Project; 32:509(1975)) indicates the possibility of delta/sup 18/0 in deep sea cherts not being frozen in until several tens of millions of years after deposition. Cherts of any Age show a spread of delta/sup 18/0 values, increasing diagenesis being reflected in a lowering of delta/sup 18/0. Drusy quartz has the lowest delta/sup 18/0 values. On land exposed cherts are consistently depleted in /sup 18/0 in comparison to their deep sea time equivalent cherts. Water extracted from deep sea cherts ranges between 0.5 and 1.4 wt%. deltaD of this water ranges between -78 and -95 parts per thousand and is not a function of delta/sup 18/0 of the cherts (or the temperature of their formation).

  14. Stable isotope deltas: Tiny, yet robust signatures in nature

    Science.gov (United States)

    Brand, Willi A.; Coplen, Tyler B.

    2012-01-01

    Although most of them are relatively small, stable isotope deltas of naturally occurring substances are robust and enable workers in anthropology, atmospheric sciences, biology, chemistry, environmental sciences, food and drug authentication, forensic science, geochemistry, geology, oceanography, and paleoclimatology to study a variety of topics. Two fundamental processes explain the stable isotope deltas measured in most terrestrial systems: isotopic fractionation and isotope mixing. Isotopic fractionation is the result of equilibrium or kinetic physicochemical processes that fractionate isotopes because of small differences in physical or chemical properties of molecular species having different isotopes. It is shown that the mixing of radioactive and stable isotope end members can be modelled to provide information on many natural processes, including 14C abundances in the modern atmosphere and the stable hydrogen and oxygen isotopic compositions of the oceans during glacial and interglacial times. The calculation of mixing fractions using isotope balance equations with isotope deltas can be substantially in error when substances with high concentrations of heavy isotopes (e.g. 13C, 2H, and 18O ) are mixed. In such cases, calculations using mole fractions are preferred as they produce accurate mixing fractions. Isotope deltas are dimensionless quantities. In the International System of Units (SI), these quantities have the unit 1 and the usual list of prefixes is not applicable. To overcome traditional limitations with expressing orders of magnitude differences in isotope deltas, we propose the term urey (symbol Ur), after Harold C. Urey, for the unit 1. In such a manner, an isotope delta value expressed traditionally as−25 per mil can be written as−25 mUr (or−2.5 cUr or−0.25 dUr; the use of any SI prefix is possible). Likewise, very small isotopic differences often expressed in per meg ‘units’ are easily included (e.g. either+0.015 ‰ or+15 per meg

  15. Controls on the stable isotope compositions of travertine from hyperalkaline springs in Oman: Insights from clumped isotope measurements

    Science.gov (United States)

    Falk, E. S.; Guo, W.; Paukert, A. N.; Matter, J. M.; Mervine, E. M.; Kelemen, P. B.

    2016-11-01

    Carbonate formation at hyperalkaline springs is typical of serpentinization in peridotite massifs worldwide. These travertines have long been known to exhibit large variations in their carbon and oxygen isotope compositions, extending from apparent equilibrium values to highly depleted values. However, the exact causes of these variations are not well constrained. We analyzed a suite of well-characterized fresh carbonate precipitates and travertines associated with hyperalkaline springs in the peridotite section of the Samail ophiolite, Sultanate of Oman, and found their clumped isotope compositions vary systematically with formation environments. Based on these findings, we identified four main processes controlling the stable isotope compositions of these carbonates. These include hydroxylation of CO2, partial isotope equilibration of dissolved inorganic carbon, mixing between isotopically distinct carbonate end-members, and post-depositional recrystallization. Most notably, in fresh crystalline films on the surface of hyperalkaline springs and in some fresh carbonate precipitates from the bottom of hyperalkaline pools, we observed large enrichments in Δ47 (up to ∼0.2‰ above expected equilibrium values) which accompany depletions in δ18O and δ13C, yielding about 0.01‰ increase in Δ47 and 1.1‰ decrease in δ13C for every 1‰ decrease in δ18O, relative to expected equilibrium values. This disequilibrium trend, also reflected in preserved travertines ranging in age from modern to ∼40,000 years old, is interpreted to arise mainly from the isotope effects associated with the hydroxylation of CO2 in high-pH fluids and agrees with our first-order theoretical estimation. In addition, in some fresh carbonate precipitates from the bottom of hyperalkaline pools and in subsamples of one preserved travertine terrace, we observed additional enrichments in Δ47 at intermediate δ13C and δ18O, consistent with mixing between isotopically distinct carbonate end

  16. Identification of long-term carbon sequestration in soils with historical inputs of biochar using novel stable isotope and spectroscopic techniques

    Science.gov (United States)

    Hernandez-Soriano, Maria C.; Kerré, Bart; Hardy, Brieuc; Dufey, Joseph; Smolders, Erik

    2013-04-01

    Biochar is the collective term for organic matter (OM) that has been produced by pyrolysis of biomass, e.g. during production of charcoal or during natural processes such as bush fires. Biochar production and application is now suggested as one of the economically feasible options for global C-sequestration strategies. The C-sequestration in soil through application of biochar is not only related to its persistence (estimated lifetime exceeds 1000 year in soil), but also due to indirect effects such as its potential to adsorb and increase OM stability in soil. Historical charcoal production sites that had been in use >200 years ago in beech/oak forests have been localized in the south of Belgium. Aerial photography identified black spots in arable land on former forest sites. Soil sampling was conducted in an arable field used for maize production near Mettet (Belgium) where charcoal production was intensive until late 18th century. Soils were sampled in a horizontal gradient across the 'black soils' that extend of few decametres, collecting soil from the spots (Biochar Amended, BA) as well as from the non-biochar amended (NBA). Stable C isotope composition was used to estimate the long-term C-sequestration derived from crops in these soils where maize had been produced since about 15 years. Because C in the biochar originates in forest wood (C3 plants), its isotopic signature (δ13C) differs from the maize (a C4 plant). The C and N content and the δ13C were determined for bulk soil samples and for microaggregate size fractions separated by wet sieving. Fourier Transform Infrared Spectroscopy (FTIR) coupled to optical microscopy was used to obtaining fingerprints of biochar and OM composition for soil microaggregates. The total C content in the BA soil (5.5%) and the C/N ratio (16.9) were higher than for NBA (C content 2.7%; C/N ratio 12.6), which confirms the persistence of OM in the BA. The average isotopic signature of bulk soil from BA (-26.08) was slightly

  17. Seasonal Cyclicity in Trace Elements and Stable Isotopes of Modern Horse Enamel.

    Directory of Open Access Journals (Sweden)

    Niels J de Winter

    Full Text Available The study of stable isotopes in fossil bioapatite has yielded useful results and has shown that bioapatites are able to faithfully record paleo-environmental and paleo-climatic parameters from archeological to geological timescales. In an effort to establish new proxies for the study of bioapatites, intra-tooth records of enamel carbonate stable isotope ratios from a modern horse are compared with trace element profiles measured using laboratory micro X-Ray Fluorescence scanning. Using known patterns of tooth eruption and the relationship between stable oxygen isotopes and local temperature seasonality, an age model is constructed that links records from six cheek upper right teeth from the second premolar to the third molar. When plotted on this age model, the trace element ratios from horse tooth enamel show a seasonal pattern with a small shift in phase compared to stable oxygen isotope ratios. While stable oxygen and carbon isotopes in tooth enamel are forced respectively by the state of the hydrological cycle and the animal's diet, we argue that the seasonal signal in trace elements reflects seasonal changes in dust intake and diet of the animal. The latter explanation is in agreement with seasonal changes observed in carbon isotopes of the same teeth. This external forcing of trace element composition in mammal tooth enamel implies that trace element ratios may be used as proxies for seasonal changes in paleo-environment and paleo-diet.

  18. Seasonal Cyclicity in Trace Elements and Stable Isotopes of Modern Horse Enamel.

    Science.gov (United States)

    de Winter, Niels J; Snoeck, Christophe; Claeys, Philippe

    2016-01-01

    The study of stable isotopes in fossil bioapatite has yielded useful results and has shown that bioapatites are able to faithfully record paleo-environmental and paleo-climatic parameters from archeological to geological timescales. In an effort to establish new proxies for the study of bioapatites, intra-tooth records of enamel carbonate stable isotope ratios from a modern horse are compared with trace element profiles measured using laboratory micro X-Ray Fluorescence scanning. Using known patterns of tooth eruption and the relationship between stable oxygen isotopes and local temperature seasonality, an age model is constructed that links records from six cheek upper right teeth from the second premolar to the third molar. When plotted on this age model, the trace element ratios from horse tooth enamel show a seasonal pattern with a small shift in phase compared to stable oxygen isotope ratios. While stable oxygen and carbon isotopes in tooth enamel are forced respectively by the state of the hydrological cycle and the animal's diet, we argue that the seasonal signal in trace elements reflects seasonal changes in dust intake and diet of the animal. The latter explanation is in agreement with seasonal changes observed in carbon isotopes of the same teeth. This external forcing of trace element composition in mammal tooth enamel implies that trace element ratios may be used as proxies for seasonal changes in paleo-environment and paleo-diet.

  19. Intra-annual variability of carbon and nitrogen stable isotopes in suspended organic matter in waters of the western continental shelf of India

    Directory of Open Access Journals (Sweden)

    M. V. Maya

    2011-11-01

    Full Text Available Intra-annual variations of δ13C and δ15N of water-column suspended particulate organic matter (SPOM have been inve