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Hürkamp, Kerstin, Nadine Zentner, Anne Reckerth, Stefan Weishaupt, Karl-Friedrich Wetzel, Jochen Tschiersch i Christine Stumpp. "Spatial and Temporal Variability of Snow Isotopic Composition on Mt. Zugspitze, Bavarian Alps, Germany". Journal of Hydrology and Hydromechanics 67, nr 1 (1.03.2019): 49–58. http://dx.doi.org/10.2478/johh-2018-0019.
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Abstract High amounts of precipitation are temporarily stored in high-alpine snow covers and play an important role for the hydrological balance. Stable isotopes of hydrogen (δ2H) and oxygen (δ18O) in water samples have been proven to be useful for tracing transport processes in snow and meltwater since their isotopic ratio alters due to fractionation. In 18 snow profiles of two snowfall seasons, the temporal and spatial variation of isotopic composition was analysed on Mt. Zugspitze. The δ18O and δ2H ranged between -26.7‰ to -9.3‰ and -193.4‰ to -62.5‰ in 2014/2015 and between -26.5‰ to -10.5‰ and -205.0‰ to -68.0‰ in 2015/2016, respectively. Depth-integrated samples of entire 10 cm layers and point measurements in the same layers showed comparable isotopic compositions. Isotopic composition of the snowpack at the same sampling time in spatially distributed snow profiles was isotopically more similar than that analysed at the same place at different times. Melting and refreezing were clearly identified as processes causing isotope fractionation in surficial, initial base or refrozen snow layers. For the future, a higher sampling frequency with detailed isotopic composition measurements during melt periods are recommended to improve the understanding of mass transport associated with snowmelt.
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Uemura, Ryu, Yudai Kina, Chuan-Chou Shen i Kanako Omine. "Experimental evaluation of oxygen isotopic exchange between inclusion water and host calcite in speleothems". Climate of the Past 16, nr 1 (7.01.2020): 17–27. http://dx.doi.org/10.5194/cp-16-17-2020.
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Abstract. The oxygen and hydrogen isotopic compositions of water in fluid inclusions in speleothems are important hydroclimate proxies because they provide information on the isotopic compositions of rainwater in the past. Moreover, because isotopic differences between fluid inclusion water and the host calcite provide information on the past isotopic fractionation factor, they are also useful for quantitative estimation of past temperature changes. The oxygen isotope ratio of inclusion water (δ18Ofi), however, may be affected by isotopic exchange between the water and the host carbonate. Thus, it is necessary to estimate the bias caused by this postdepositional effect for precise reconstruction of paleotemperatures. Here, we evaluate the isotopic exchange reaction between inclusion water and host calcite based on a laboratory experiment involving a natural stalagmite. Multiple stalagmite samples cut from the same depth interval were heated at 105 ∘C in the laboratory from 0 to 80 h. Then, the isotopic compositions of the inclusion water were measured. In the 105 ∘C heating experiments, the δ18Ofi values increased from the initial value by 0.7 ‰ and then remained stable after ca. 20 h. The hydrogen isotope ratio of water showed no trend in response to the heating experiments, suggesting that the hydrogen isotopic composition of fluid inclusion water effectively reflects the composition of past drip water. We then evaluated the process behind the observed isotopic variations using a partial equilibration model. The experimental results are best explained by the assumption that a thin CaCO3 layer surrounding the inclusion reacted with the water. The amount of CaCO3 that reacted with the water is equivalent to 2 % of the water inclusions in molar terms. These results suggest that the magnitude of the isotopic exchange effect has a minor influence on paleotemperature estimates for Quaternary climate reconstructions.
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Kennedy, Brenda V., i H. Roy Krouse. "Isotope fractionation by plants and animals: implications for nutrition research". Canadian Journal of Physiology and Pharmacology 68, nr 7 (1.07.1990): 960–72. http://dx.doi.org/10.1139/y90-146.
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The isotopic compositions of animal tissues, minerals, and fluids reflect those of ingested food and water and inhaled gases. This relationship is illustrated by a review of data pertaining to five light elements of biological interest (carbon, nitrogen, hydrogen, oxygen, and sulphur). Processes affecting the isotopic composition of inorganic compounds in reservoirs are summarized, and isotope fractionation during transfer of elements from these inorganic reservoirs through progressive trophic levels of food webs is discussed. Variability of δ values within and among individuals, populations, and species of plants and animals is attributed to at least six factors: locality, dietary selectivity, biochemical composition of food, isotope effects in metabolic processes, turnover rates, and stress. Features of a variety of terrestrial and aquatic ecosystems are used to illustrate basic concepts. Future research should seek to clarify specific mechanisms affecting δ values during the transfer of elements through food webs.Key words: food webs, stable isotopes, isotope fractionation, ecosystems.
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Qu, Simin, Xueqiu Chen, Yifan Wang, Peng Shi, Shuai Shan, Jianfeng Gou i Peng Jiang. "Isotopic Characteristics of Precipitation and Origin of Moisture Sources in Hemuqiao Catchment, a Small Watershed in the Lower Reach of Yangtze River". Water 10, nr 9 (31.08.2018): 1170. http://dx.doi.org/10.3390/w10091170.
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The stable isotopes of oxygen and hydrogen in the water cycle have become a significant tool to study run-off formation, hydrograph separation, and the origin of precipitation. Precipitation assessment based on isotopic data has a potential implication for moisture sources. In the study, δD and δ18O of precipitation samples collected from six rainfall events were analyzed for stable isotope composition to provide implication of isotopic characteristics as well as moisture sources in Hemuqiao basin within Lake Tai drainage basin, eastern China. In these events, stable oxygen and hydrogen isotopic composition of precipitation had strong variations. Models of the meteoric water line and deuterium excess for different rainfall types (typhoon and plum rain, which is caused by precipitation along a persistent stationary front known as the Meiyu front for nearly two months during the late spring and early summer between eastern Russia, China, Taiwan, Korea and Japan) were established. Compared with plum rain, the moisture source of typhoon events had higher relative humidity and temperature. Moisture transport pathways were traced using the Hybrid Single-Particle Lagrangian Integrated Trajectory Model (HYSPLIT Model, developed by NOAA, Washington DC, U.S.) to verify the linkage with isotopic composition and moisture source. The moisture sources of typhoon events mostly derived from tropical ocean air with higher isotopic value, while that of plum rain events came from near-source local air with lower isotopic value.
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Pieterse, G., M. C. Krol, A. M. Batenburg, L. P. Steele, P. B. Krummel, R. L. Langenfelds i T. Röckmann. "Global modelling of H<sub>2</sub> mixing ratios and isotopic compositions with the TM5 model". Atmospheric Chemistry and Physics Discussions 11, nr 2 (17.02.2011): 5811–66. http://dx.doi.org/10.5194/acpd-11-5811-2011.
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Abstract. The isotopic composition of molecular hydrogen (H2) contains independent information for constraining the global H2 budget. To explore this, we have implemented hydrogen sources and sinks, including their isotopic composition, into the global chemistry transport model TM5. For the first time, a global model now includes a simplified but explicit isotope reaction scheme for the photochemical production of H2. We present a comparison of modelled results for the H2 mixing ratio and isotope composition with available measurements on the seasonal to inter annual time scales for the years 2001–2007. The base model results agree well with observations for H2 mixing ratios. For δD[H2], modelled values are slightly lower than measurements. A detailed sensitivity study is performed to identify the most important parameters for modelling the isotopic composition of H2. The results show that on the global scale, the discrepancy between model and measurements can be closed by adjusting the default values of the isotope effects in deposition, photochemistry and the stratosphere-troposphere exchange within the known range of uncertainty. However, the available isotope data do not provide sufficient information to uniquely constrain the global isotope budget. Therefore, additional studies focussing on the isotopic composition near the tropopause and on the isotope effects in the photochemistry and deposition are recommended.
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Hamzić Gregorčič, Staša, Doris Potočnik, Federica Camin i Nives Ogrinc. "Milk Authentication: Stable Isotope Composition of Hydrogen and Oxygen in Milks and Their Constituents". Molecules 25, nr 17 (2.09.2020): 4000. http://dx.doi.org/10.3390/molecules25174000.
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This paper summarises the isotopic characteristics, i.e., oxygen and hydrogen isotopes, of Slovenian milk and its major constituents: water, casein, and lactose. In parallel, the stable oxygen isotope ratios of cow, sheep, and goat’s milk were compared. Oxygen stable isotope ratios in milk water show seasonal variability and are also 18O enriched in relation to animal drinking water. The δ18Owater values were higher in sheep and goat’s milk when compared to cow milk, reflecting the isotopic composition of drinking water source and the effect of differences in the animal’s thermoregulatory physiologies. The relationship between δ18Omilk and δ18Olactose is an indication that even at lower amounts (>7%) of added water to milk can be determined. This procedure once validated on an international scale could become a reference method for the determination of milk adulteration with water.
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Li, Xiangnan, Baisha Weng, Denghua Yan, Tianling Qin, Kun Wang, Wuxia Bi, Zhilei Yu i Batsuren Dorjsuren. "Anthropogenic Effects on Hydrogen and Oxygen Isotopes of River Water in Cities". International Journal of Environmental Research and Public Health 16, nr 22 (12.11.2019): 4429. http://dx.doi.org/10.3390/ijerph16224429.
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Stable hydrogen and oxygen isotopes are important indicators for studying water cycles. The isotopes are not only affected by climate, but are also disturbed by human activities. Urban construction has changed the natural attributes and underlying surface characteristics of river basins, thus affecting the isotopic composition of river water. We collected urban river water isotope data from the Global Network for Isotopes in Rivers (GNIR) database and the literature, and collected river water samples from the Naqu basin and Huangshui River basin on the Tibetan Plateau to measure hydrogen and oxygen isotopes. Based on 13 pairs of urban area and non-urban area water samples from these data, the relationship between the isotopic values of river water and the artificial surface area of cities around rivers was analyzed. The results have shown that the hydrogen and oxygen isotope (δD and δ18O) values of river water in urban areas were significantly higher than those in non-urban areas. The isotopic variability of urban and non-urban water was positively correlated with the artificial surface area around the rivers. In addition, based on the analysis of isotope data from 21 rivers, we found that the cumulative effects of cities on hydrogen and oxygen isotopes have led to differences in surface water line equations for cities with different levels of development. The combined effects of climate and human factors were the important reasons for the variation of isotope characteristics in river water in cities. Stable isotopes can not only be used to study the effects of climate on water cycles, but also serve as an important indicator for studying the degree of river development and utilization.
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Abiye, Tamiru A., Molla B. Demlie i Haile Mengistu. "An Overview of Aquifer Physiognomies and the δ18O and δ2H Distribution in the South African Groundwaters". Hydrology 8, nr 2 (19.04.2021): 68. http://dx.doi.org/10.3390/hydrology8020068.
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A comprehensive assessment of the stable isotope distribution in the groundwater systems of South Africa was conducted in relation to the diversity in the aquifer lithology and corresponding hydraulic characteristics. The stable isotopes of oxygen (18O) and hydrogen (2H) in groundwater show distinct spatial variation owing to the recharge source and possibly mixing effect in the aquifers with the existing water, where aquifers are characterized by diverse hydraulic conductivity and transmissivity values. When the shallow aquifer that receives direct recharge from rainfall shows a similar isotopic signature, it implies less mixing effect, while in the case of deep groundwater interaction between recharging water and the resident water intensifies, which could change the isotope signature. As aquifer depth increases the effect of mixing tends to be minimal. In most cases, the isotopic composition of recharging water shows depletion in the interior areas and western arid zones which is attributed to the depleted isotopic composition of the moisture source. The variations in the stable isotope composition of groundwater in the region are primarily controlled by the isotope composition of the rainfall, which shows variable isotope composition as it was observed from the local meteoric water lines, in addition to the evaporation, recharge and mixing effects.
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Kakareka, S. V., T. I. Kukharchyk, A. A. Ekaykin i Yu G. Giginyak. "Stable isotopes in the snow of the coastal areas of Antarctica". Doklady of the National Academy of Sciences of Belarus 65, nr 4 (2.09.2021): 495–502. http://dx.doi.org/10.29235/1561-8323-2021-65-4-495-502.
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The first results of study of stable isotopes of oxygen (δ18O) and hydrogen (δD) in the snow samples taken on the islands of Marguerite Bay (Antarctic Peninsula), in the Vecherny Oasis (Enderby Land), and Larsemann Hills (Princess Elizabeth Land) by the participants of the 12th Belarusian Antarctic Expedition (January–March 2020) are presented. The concentration of water isotopes: deuterium (D) and oxygen-18 (18O) in the samples was determined using a laser isotope composition analyzer Picarro L2130. A total of 32 snow samples were analyzed. The statistical parameters of the isotopic composition of snow were estimated, and the main differences in the content of δ18O and δD between the study areas were shown. A decrease in the content of heavy oxygen and hydrogen isotopes in the newly fallen snow to the old snow of the surface horizons is shown. The maximum values of δ18O and δD are typical for the Maritime Antarctica, decreasing towards the coastal zone and further – towards its continental part. The possible factors affecting the isotope content are described. It is shown that the monitoring of the isotope composition can be an integral part of the monitoring of climatic changes within the area of operation of the Belarusian Antarctic Expedition. The study of the isotopic composition of surface snow is important for the reconstruction of the paleoclimate of the marginal zone of the Antarctic ice sheet based on the ice cores study.
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Pieterse, G., M. C. Krol, A. M. Batenburg, L. P. Steele, P. B. Krummel, R. L. Langenfelds i T. Röckmann. "Global modelling of H<sub>2</sub> mixing ratios and isotopic compositions with the TM5 model". Atmospheric Chemistry and Physics 11, nr 14 (20.07.2011): 7001–26. http://dx.doi.org/10.5194/acp-11-7001-2011.
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Abstract. The isotopic composition of molecular hydrogen (H2) contains independent information for constraining the global H2 budget. To explore this, we have implemented hydrogen sources and sinks, including their stable isotopic composition and isotope fractionation constants, into the global chemistry transport model TM5. For the first time, a global model now includes a simplified but explicit isotope reaction scheme for the photochemical production of H2. We present a comparison of modelled results for the H2 mixing ratio and isotope composition with available measurements on seasonal to inter annual time scales for the years 2001–2007. The base model results agree well with observations for H2 mixing ratios. For δD[H2], modelled values are slightly lower than measurements. A detailed sensitivity study is performed to identify the most important parameters for modelling the isotopic composition of H2. The results show that on the global scale, the discrepancy between model and measurements can be closed by adjusting the default values of the isotope effects in deposition, photochemistry and the stratosphere-troposphere exchange within the known range of uncertainty. However, the available isotope data do not provide sufficient information to uniquely constrain the global isotope budget. Therefore, additional studies focussing on the isotopic composition near the tropopause and on the isotope effects in the photochemistry and deposition are recommended.
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Novikov, Dmitry A., Aleksandr N. Pyrayev, Fedor F. Dultsev, Anatoliy V. Chernykh, Svetlana V. Bakustina i Dmitry V. Ulyanov. "FORMATION CONDITIONS OF GROUNDWATER OF THE UPPER JURASSIC OF THE CENTRAL REGIONS OF THE ZAURAL MEGAMONOCLYSIS". Interexpo GEO-Siberia 2, nr 1 (21.05.2021): 181–90. http://dx.doi.org/10.33764/2618-981x-2021-2-1-181-190.
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The article presents the first results of complex isotope-hydrogeochemical studies of reservoir waters of the Upper Jurassic deposits of the central regions of the Zaural megamonoclysis. It was shown that most waters have a narrow distribution of oxygen and hydrogen isotopes (δD from -103.2 to -85.6 ‰ and δO from -15.4 to -12.9 ‰). Some of them have pronounced excursions on the isotopic composition, which indicates a difference in their genesis: from condensate to mixed with ancient infiltrogenic. The isotopic composition of carbon of water-dissolved carbon dioxide (δС from -41.6 to -16.3 ‰) indicates its biogenic origin and the possibility of interstratal flows from overlying horizons.
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Benbow, Timothy J., Alan R. Hayman, Robert Van Hale i Russell Frew. "Preparation of aqueous fatty acids for hydrogen and carbon stable isotope analysis by solid phase extraction". Marine and Freshwater Research 64, nr 4 (2013): 294. http://dx.doi.org/10.1071/mf12192.
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Stable isotope analyses of fatty acids in environmental waters provides important information as to their source(s). Analysis is often confounded due to low concentrations of fatty acids and/or a complex sample matrix requiring separation of the target analyte. The purpose of this study was to validate a method to extract fatty acids from natural waters using solid phase extraction (SPE) before compound specific isotope analysis (CSIA). Three SPE cartridges and multiple eluting solvents were tested to determine the efficiency, isotopic fractionation, and reproducibility of each extraction technique. Our results indicated that surface-modified styrene divinylbenzene cartridges, when eluted with methanol, caused negligible fractionation of the hydrogen isotopes and minimal fractionation of the carbon isotopes, but that isotopic fractionation occurred when compounds were only partially eluted from SPE cartridges. Compounds were also extracted from landfill leachate using both SPE and liquid–liquid extraction (LLE). The hydrogen isotope composition (δ2H) of compounds extracted from water using either method were within experimental precision and the carbon isotope composition (δ13C) of all but one fatty acid were within experimental precision. Therefore, these experiments prove the aforementioned SPE methods to be a convenient and precise method to extract fatty acids from natural waters before CSIA.
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Feng, Xiahong, Haiting Cui, Kuilian Tang i Laura E. Conkey. "Tree-Ring δD as an Indicator of Asian Monsoon Intensity". Quaternary Research 51, nr 3 (maj 1999): 262–66. http://dx.doi.org/10.1006/qres.1999.2039.
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AbstractOxygen and hydrogen isotopic compositions of meteoric water are known to correlate with surface air temperature, except in tropical areas. This relationship has been described using a number of terms corresponding to specific observations, such as latitude, altitude and seasonal effects. However, these temperature effects do not seem to apply to precipitation in monsoonal areas of Asia. Questions have been raised as to whether the isotopic composition of meteoric water can be used to reconstruct paleomonsoon intensity. Tree rings of two modern spruce trees (Picea meyeri) and a 10,000-yr-old timber (Picea jezoensis) were analyzed for hydrogen isotopic composition. On average, the older tree is depleted in deuterium by 45‰ compared to the modern trees. We attribute this isotopic depletion to the strength of summer monsoons, which were more intense in the early Holocene than at present. Although this study is not definitive, it suggests that paleomonsoon intensity can be reconstructed by direct or proxy methods that yield the oxygen or hydrogen isotopic composition of meteoric water.
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Fulignati, Paolo, i Adrian J. Boyce. "Stable Isotope (δ18O, δD) Composition of Magmatic Fluids Exsolved from an Active Alkaline Magma Chamber—The Case of the AD 79 Magma Chamber of Vesuvius". Minerals 13, nr 7 (6.07.2023): 913. http://dx.doi.org/10.3390/min13070913.
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This work documents, for the first time, the calculated oxygen and hydrogen isotope composition of the brines exsolved from the peripheral margin of the active magma alkaline chamber that fed the AD 79 (“Pompei”) eruption of Vesuvius. The exsolved hydrosaline fluids had a constant δ18O composition and a variable δD composition, showing a general lowering of δD at nearly constant δ18O content. We argue that the progressive fluid exsolution at the upper peripheral parts of the AD 79 magma chamber may explain this isotopic path. The modeling of the evolution of the hydrogen isotope composition of water remaining dissolved in the melt, and of the exsolved fluid as a consequence of progressive degassing, would favor multiple fluid-release events from the magmatic reservoir. A schematic model on the pulsed accumulation and release of fluids at the top of the magmatic reservoir prior to the eruption is thus proposed. The assessment of the stable isotope composition of the fluids exsolved from the AD 79 magma chamber of Vesuvius may be particularly relevant for the geochemical surveillance of the volcano as it may help to interpret the isotopic composition of fumarolic gases and its variations.
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Wei, Zhifu, Yongli Wang, Gen Wang, Xueyun Ma, Wei He, Ting Zhang, Xiaoli Yu i Yan-Rong Zou. "Isotopic Composition of Abiogenic Gas Produced in Closed-System Fischer-Tropsch Synthesis: Implications for the Origins of the Deep Songliao Basin Gases in China". Geofluids 2019 (28.08.2019): 1–13. http://dx.doi.org/10.1155/2019/2823803.
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In this study, closed-system Fischer-Tropsch synthesis was conducted at 380°C and 30 MPa for 72 h with magnetite as a catalyst. The isotopic composition of the closed-system Fischer-Tropsch synthesis gas and the composition of known abiogenic gas were systematically studied, and the deep Songliao Basin gas was also investigated. The results show that closed-system Fischer-Tropsch synthesis of gaseous hydrocarbon isotopes exhibits a partial reverse order, which includes the reverse order of methane and ethane such as δ13C-C1>δ13C-C2<δ13C-C3 and δ2H-C1>δ2H-C2<δ2H-C3. Furthermore, experimental data on the control of NaBH4 content indicates that the carbon isotopes demonstrate a reverse order on condition that the H2/CO2 (mole ratio) is equal to or greater than 4.0; meanwhile, the hydrogen isotopes show a normal order. The deep Songliao Basin hydrocarbon gas component is similar to thermogenic gas and has a trend of a transition to oceanic hydrothermal system abiogenic gas. In addition, the deep Songliao Basin gas isotopic pattern is different from both Lost City and Kidd Creek where the deep Basin gas carbon isotopic pattern has a reverse order, and the hydrogen isotopic pattern has a normal order. Therefore, the deep Basin gas might be a mixture of the oil-type gas and the coal-formed gas, which could be the cause of the isotopic reverse.
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Deme, Samiksha, Laurence Y. Yeung, Tao Sun i Cin-Ty A. Lee. "Stable isotope (C, N, O, and H) study of a comprehensive set of feathers from two Setophaga citrina". PLOS ONE 16, nr 1 (14.01.2021): e0236536. http://dx.doi.org/10.1371/journal.pone.0236536.
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Oxygen, hydrogen, carbon and nitrogen stable isotopes were measured on a comprehensive sampling of feathers from two spring Hooded Warblers (Setophaga citrina) in Texas to evaluate isotopic variability between feathers and during molt. Isotopic homogeneity within each bird was found across all four isotopic systems, supporting the hypothesis that molt in these neotropical migrants is fully completed on the breeding grounds. This homogeneity suggests that the isotopic composition of a single feather is may be representative of the whole songbird. However, each bird was found to have one or two outlier feathers, which could signify regrowth of lost feathers after prebasic molt.
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Menoud, Malika, Carina van der Veen, Dave Lowry, Julianne M. Fernandez, Semra Bakkaloglu, James L. France, Rebecca E. Fisher i in. "New contributions of measurements in Europe to the global inventory of the stable isotopic composition of methane". Earth System Science Data 14, nr 9 (23.09.2022): 4365–86. http://dx.doi.org/10.5194/essd-14-4365-2022.
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Abstract. Recent climate change mitigation strategies rely on the reduction of methane (CH4) emissions. Carbon and hydrogen isotope ratio (δ13CCH4 and δ2HCH4) measurements can be used to distinguish sources and thus to understand the CH4 budget better. The CH4 emission estimates by models are sensitive to the isotopic signatures assigned to each source category, so it is important to provide representative estimates of the different CH4 source isotopic signatures worldwide. We present new measurements of isotope signatures of various, mainly anthropogenic, CH4 sources in Europe, which represent a substantial contribution to the global dataset of source isotopic measurements from the literature, especially for δ2HCH4. They improve the definition of δ13CCH4 from waste sources, and demonstrate the use of δ2HCH4 for fossil fuel source attribution. We combined our new measurements with the last published database of CH4 isotopic signatures and with additional literature, and present a new global database. We found that microbial sources are generally well characterised. The large variability in fossil fuel isotopic compositions requires particular care in the choice of weighting criteria for the calculation of a representative global value. The global dataset could be further improved by measurements from African, South American, and Asian countries, and more measurements from pyrogenic sources. We improved the source characterisation of CH4 emissions using stable isotopes and associated uncertainty, to be used in top-down studies. We emphasise that an appropriate use of the database requires the analysis of specific parameters in relation to source type and the region of interest. The final version of the European CH4 isotope database coupled with a global inventory of fossil and non-fossil δ13CCH4 and δ2HCH4 source signature measurements is available at https://doi.org/10.24416/UU01-YP43IN (Menoud et al., 2022a).
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Oganesyants, Lev, Elena Sevostianova, Elena Kuzmina, Mikhail Ganin, Eugene Chebykin i Aleksandr Suturin. "Isotopic and Chemical Composition of the Deep Water of Lake Baikal". Food Processing: Techniques and Technology 51, nr 4 (12.01.2022): 723–32. http://dx.doi.org/10.21603/2074-9414-2021-4-723-732.
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Introduction. Due to its natural composition, the deep water of Lake Baikal can be bottled without any conserving agents. The development of large-scale production of bottled Baikal water requires its detailed study in order to protect it from counterfeit and falsification. The purpose of this work was to study the isotopic and chemical composition of the deep water of Lake Baikal and offer indicators for its identification.
Study objects and methods. The research included deep water of Lake Baikal, sampled at various points, the water from the Angara River, and the tap water from the cities of Irkutsk and Shelekhov. The tests were performed using a quadrupole ICP-MS mass spectrometer and a Delta V Plus isotope mass spectrometer with a GasBench II module.
Results and discussion. All the water samples revealed fresh water with insignificant mineralization. As for salts, the deep water samples had a lower content of sodium and chlorides, as well as a higher content of silicon. As for metals, the deep water samples contained iron, manganese, copper, and zinc; in the tap water samples, these indicators were significantly higher. Unlike that of the Angara water samples, the isotopic profile of the deep water samples was somewhat “lighter”, both in the ratio of oxygen isotopes δ18O – by 0.73‰, and hydrogen δD – by 0.49‰. The tap water samples had a higher deuterium content. The content of oxygen isotopes (δ18O) in the tap water samples was close to that in the Angara samples.
Conclusion. The complex physicochemical and isotope analyses expanded the list of identification indicators and made it possible to identify the deep water of Lake Baikal.
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Boutard, D., i W. Möller. "Isotopic effects in a–C:(H/D) films deposited from methane/hydrogen RF plasmas". Journal of Materials Research 5, nr 11 (listopad 1990): 2451–55. http://dx.doi.org/10.1557/jmr.1990.2451.
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Hard amorphous hydrocarbon films have been deposited by RF glow discharges in methane/hydrogen mixtures with different hydrogen isotopes. For CH4 + D2 and CD4 + H2 gas mixtures, the film growth rate, the density, the refractive index, and the isotopic hydrogen content are obtained as functions of the process gas composition. Further, the hydrogen loss induced by 15 keV helium ions is studied. The results are qualitatively interpreted in terms of different effects of ion bombardment during film deposition which influence the properties of the resulting films.
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Valentini, R., T. Anfodillo i J. R. Ehleringer. "Water sources and carbon isotope composition (δ13C) of selected tree species of the Italian Alps". Canadian Journal of Forest Research 24, nr 8 (1.08.1994): 1575–78. http://dx.doi.org/10.1139/x94-205.
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Selected species of the Italian Alpine region (Piceaabies (L.) Karst., Pinussylvestris L., Pinuscembra L., and Larixdecidua L.) have been investigated in terms of water-source utilization and carbon fixation estimated by the analysis of hydrogen and carbon stable isotopes composition at two sites of differing altitude (1000 and 1500 m above sea level). Larixdecidua is the species most dependent on groundwater in both sites, while Pinussylvestris utilizes rainwater to a greater extent. Concurrently, Pinussylvestris displayed the highest value of the carbon isotopic ratio (δ13C = −25.9 ± 0.6‰), while Larixdecidua had the most negative one (δ13C = −29.0 ± 0.4‰). A relationship was found between water-source utilization and carbon-isotope discrimination.
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Ansdell, Kevin M., i T. Kurtis Kyser. "The geochemistry and fluid history of the Proterozoic Laurel Lake Au–Ag deposit, Flin Flon greenstone belt". Canadian Journal of Earth Sciences 28, nr 2 (1.02.1991): 155–71. http://dx.doi.org/10.1139/e91-016.
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The Laurel Lake Au–Ag deposit is situated 25 km southwest of Flin Flon in the Proterozoic Flin Flon Domain and consists of branching quartz–muscovite–pyrite–tennantite–chalcopyrite–sphalerite–galena–electrum–carbonate veins (stage 1) surrounded by a widespread zone of sericitized and pyritized Amisk Group felsic volcanic rocks. The deposit has been deformed and metamorphosed during the Hudsonian orogeny and is crosscut by nonauriferous quartz–dolomite–tourmaline–pyrite veins (stage 2). The timing of mineralization, the lack of obvious relation to a major shear zone, and high base metal sulphide and Ag/Au ratio (5:1) distinguish this deposit from epigenetic mesothermal gold deposits in the Flin Flon Domain. Fluid inclusion and stable-isotope data indicate that the mineralizing fluids had a high temperature (>300 °C), were saline (>10.3 wt.% NaCl equivalent) and CO2 bearing and had an isotopic composition similar to modified seawater. This fluid leached sulphur, base metals, and precious metals as it interacted with Amisk Group volcanic rocks. The hydrogen isotopic compositions of fine-grained muscovites in the surrounding altered felsic volcanic rocks have been reset during later metamorphism, whereas the coarse stage 1 vein muscovites have partially preserved their primary hydrogen isotopic compositions and fluorine contents. Stage 2 veins were deposited from low-salinity (<6.4 wt.% NaCl equivalent), CO2-bearing fluids, which also have the hydrogen and oxygen isotopic compositions of modified seawater. The Laurel Lake deposit has fluid, vein, and alteration characteristics that distinguish it from both epithermal and mesothermal deposits, and they can be explained by the involvement of modified seawater.
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Borodulina, Galina, Igor Tokarev i Evgeny Yakovlev. "Isotope Composition of Natural Water in Lake Onega Basin". Water 15, nr 10 (13.05.2023): 1855. http://dx.doi.org/10.3390/w15101855.
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In 2009–2018, the isotopic composition of oxygen and hydrogen in the atmospheric precipitation, groundwater and river and lake water of Lake Onega basin was studied. The weighted annual isotope composition of precipitation at Petrozavodsk was δ18O = −11.7‰ and δ2H = −84‰ and varied from −30.9 to −4.1‰ for δ18O and from −23 to −22‰ for δ2H. The isotopic composition of the water in Lake Onega was relatively uniform from −11.5 to −9.3‰ for δ18O and from −85 to −71‰ for δ2H. In the bays, the isotopic composition of the water varied more substantially than in the central part of the lake due to the river runoff during springtime flooding. In late summer, the concentrations of deuterium and oxygen-18 increased in the lake water, and figurative points on the δ2H vs. δ18O diagram shifted above the meteoric line. The absorption of the isotopically heavy summer precipitation and disequilibrium isotope fractionation during evaporation led to the enrichment of the lake water by heavy isotopes. Experiments were conducted to estimate the evaporation influence on the isotope enrichment of the residual water, and a comparison of the obtained isotope data with the experimental function showed that commonly, about 4% and up to 12% of water was lost during the spring and summer, respectively. In the water of the tributaries, the abundance of the deuterium and oxygen-18 varied in a wider scale than in the lakes, from −14.4 to −9.1‰ for δ18O and from −102 to −73‰ for δ2H. An evaporation loss of up to 35% was found for the rivers in late summer, and this value was proportional to the area of lakes and wetlands in the elementary watershed. The initial isotope composition of the water in the tributaries prior to evaporation was estimated to be δ18O ≈ −14.1‰ and δ2H ≈ −103‰ on average and crossed the approximation and meteoric lines. This estimation was close to the average composition of the groundwater, i.e., δ18O ≈ −13.4‰ and δ2H ≈ −94‰ on the Lake Onega catchment. The slightly increased isotope depletion of the calculated composition in the initial river water in comparison with the groundwater was the result of the contribution of the spring snowmelt water, which had a significant influence on the lake water balance.
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Bujakaite, M. I., V. Yu Lavrushin i B. G. Pokrovsky. "Strontium isotopic composition in waters of mud volcanoes of Azerbaijan". Литология и полезные ископаемые, nr 5 (20.10.2019): 391–403. http://dx.doi.org/10.31857/s0024-497x20195391-403.
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The isotopic composition of strontium was studied in the waters of 22 Azerbaijan mud volcanoes, in which the isotope composition of oxygen and hydrogen, as well as the concentration of macro and micro elements, was previously [Lavrushin et al., 2015] determined. 87Sr/86Sr ratios in the waters of Azerbaijan mud volcanoes are within 0.70670.7083. The minimum ratio was established in Neftechala Yuzhnaya volcano, located in the south of the territory ‒ in the Kura region, which is characterized by the lowest average values of 87Sr/86Sr = 0.70700.0003 and 18O = 2.01.8 compared to volcanoes situated northern ‒ in Shemakha ‒ Gobustan, Absheron and Caspian regions (87Sr/86Sr average = 0.70760.0005, 18O average = 4.82.5). The relation between the strontium isotopic composition and the isotopic composition of oxygen suggests that the formation of the isotopic characteristics of the mud volcanic waters of Azerbaijan involves two main sources, one of which is predominantly associated with sedimentary carbonates of Cretaceous-Paleogene age, and the second, prevailing in the Kura region, has traces of isotopic exchange with volcanic rocks. The role of strontium dissolved in the sea water, as well as strontium, which could be extracted from modern terrigenous sediments of the Caspian Sea and terrigenous clay rocks of the Maikop series in the mud volcanic waters of Azerbaijan is insignificant.
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Guo, Rong, Shengjie Wang, Mingjun Zhang, Athanassios A. Argiriou, Xuemei Liu, Bo Su, Xue Qiu i in. "Stable Hydrogen and Oxygen Isotope Characteristics of Bottled Water in China: A Consideration of Water Source". Water 11, nr 5 (22.05.2019): 1065. http://dx.doi.org/10.3390/w11051065.
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The origin of bottled water can be identified via its stable isotope signature because of the spatial variation of the stable isotope composition of natural waters. In this paper, the spatial pattern of δ2H and δ18O values were analyzed for a total of 242 bottled water samples produced at 137 sites across China that were randomly purchased during 2014–2015. The isotopic ratios of bottled water vary between −166‰ and −19‰ for δ2H, and between −21.6‰ and −2.1‰ for δ18O. Based on multiple regression analyses using meteorological and geographical parameters, an isoscape of Chinese bottled water was created. The results showed that altitude among spatial parameters and precipitation amount and air temperature among meteorological parameters were major natural factors determining the isotopic variation of bottled water. Our findings indicate the potential and the significance of the use of stable isotopes for the source identification of bottled water. An analysis of different origin types (spring, glacier and unmarked) and several different brands of bottled water in the same location reflected different production processes and source signatures.
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Dar, Shaakir Shabir, Prosenjit Ghosh, Ankit Swaraj i Anil Kumar. "Craig–Gordon model validation using stable isotope ratios in water vapor over the Southern Ocean". Atmospheric Chemistry and Physics 20, nr 19 (6.10.2020): 11435–49. http://dx.doi.org/10.5194/acp-20-11435-2020.
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Abstract. The stable oxygen and hydrogen isotopic composition of water vapor over a water body is governed by the isotopic composition of surface water and ambient vapor, exchange and mixing processes at the water–air interface, and the local meteorological conditions. These parameters form inputs to the Craig–Gordon models, used for predicting the isotopic composition of vapor produced from the surface water due to the evaporation process. In this study we present water vapor, surface water isotope ratios and meteorological parameters across latitudinal transects in the Southern Ocean (27.38–69.34 and 21.98–66.8∘ S) during two austral summers. The performance of Traditional Craig–Gordon (TCG) (Craig and Gordon, 1965) and the Unified Craig–Gordon (UCG) (Gonfiantini et al., 2018) models is evaluated to predict the isotopic composition of evaporated water vapor flux in the diverse oceanic settings. The models are run for the molecular diffusivity ratios suggested by Merlivat (1978), Cappa et al. (2003) and Pfahl and Wernli (2009), referred to as MJ, CD and PW, respectively, and different turbulent indices (x), i.e., fractional contribution of molecular vs. turbulent diffusion. It is found that the UCGx=0.8MJ, UCGx=0.6CD, TCGx=0.6MJ and TCGx=0.7CD models predicted the isotopic composition that best matches with the observations. The relative contribution from locally generated and advected moisture is calculated at the water vapor sampling points, along the latitudinal transects, assigning the representative end-member isotopic compositions, and by solving the two-component mixing model. The results suggest a varying contribution of the advected westerly component, with an increasing trend up to 65∘ S. Beyond 65∘ S, the proportion of Antarctic moisture was found to be prominent and increasing linearly towards the coast.
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Chelnokov, G. A., I. V. Bragin, I. A. Kharitonova, K. Yu Bushkareva, V. Yu Lavrushin, R. V. Zharkov, B. I. Chelnokova i A. A. Karabtsov. "GEOCHEMISTRY OF MINERAL WATERS AND HYDROGENIC SEDIMENTS OF THE ANTONOV HYDROSULPHURIC MINERAL SPRING, SAKHALIN ISLAND". Tikhookeanskaya Geologiya 39, nr 6 (2020): 98–113. http://dx.doi.org/10.30911/0207-4028-2020-39-6-98-113.
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Original data on the isotopic and chemical composition of mineral waters, cold ground and surface waters, as well as hydrogenic deposits of the Antonovsky manifestation of hydrogen sulfide mineral waters (the coast of the Tatar Strait, Sakhalin Island) are provided in the article. For the first time, data on the content of oxygen and hydrogen isotopes in groundwaters and surface waters, the volumetric activity of radon and the rare-earth elements as well were obtained. Based on automatic monitoring of the physical parameters of the waters, their hydrogeological characteristics were determined and balneological properties were assessed. It has been determined that the mineral waters of the spring are weakly alkaline, hydrocarbonate-chloride calcium-sodium, with TDS of up to 1 g/l. According to isotope data, the genesis of waters is atmospheric, and the circulation time is less than 60 years. The gas composition is dominated by nitrogen of atmospheric genesis (δ15N = 0.0). High contents of organic carbon (Corg. = 56.6 mg/l) are explained by the processes of interaction of groundwaters with organic matter of water-bearing rocks. When organic matter decomposes in the presence of sulfates and without oxygen, hydrogen sulfide is released, giving rise to a number of intermediate and stable sulfur compounds in hydrogenic sediments and bacterial mats. Elemental, sulfide and sulfate forms of sulfur have been determined in the bottom sediments as well as new formations of the mineral spring, using electron microscopy. The interaction of waters with organic matter of rocks plays a significant role in the formation of the elemental composition of hydrogenic and biogenic deposits of the Antonovsky hydrogen sulphide mineral spring and their enrichment with such metals as Zn, Ge, As, Sr, Ba, U, and Th as well. A characteristic feature of mineral waters is the presence of a pronounced positive europium anomaly, which is typical for waters with low Eh values.
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Абдуллина, Г. И., Л. Г. Аскинази, А. А. Белокуров, Н. А. Жубр, В. А. Корнев, С. В. Крикунов, С. В. Лебедев i in. "Определение изотопного состава плазмы по частоте альфвеновских колебаний в токамаке ТУМАН-3М". Письма в журнал технической физики 45, nr 15 (2019): 51. http://dx.doi.org/10.21883/pjtf.2019.15.48089.17813.
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The possibility of determination of evolution of the plasma isotope composition from Alfven oscillation frequency in discharges with pulsed deuterium puffing into hydrogen plasma and hydrogen into deuterium plasma in ohmically heated plasma in TUMAN-3M tokamak is discussed. Isotopic ratio found from the Alfven oscillation spectra by this method is relative concentrations of hydrogen nH/(nH+nD) or deuterium nD/(nH+nD) in the mixed hydrogen-deuterium plasma. These values were found to agree qualitatively with the results of optical spectroscopy measurements and with neutral particle analysis data.
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Davies, Lauren J., Ryan C. McKellar, Karlis Muehlenbachs i Alexander P. Wolfe. "Isotopic characterization of organic matter from the Danek Bonebed (Edmonton, Alberta, Canada) with special reference to amber". Canadian Journal of Earth Sciences 51, nr 11 (listopad 2014): 1017–22. http://dx.doi.org/10.1139/cjes-2014-0057.
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During the course of excavating the Maastrichtian Danek Bonebed in the city of Edmonton, a range of well-preserved organic materials was recovered alongside vertebrate remains, including amber, coal, and unpermineralized plant fragments. Herein, we report carbon and hydrogen stable isotopic characterizations of these materials to provide ancillary insights into genesis of the fossil deposit. These analyses permit isotopic comparisons between the various organic fractions at the Danek locality, as well as with other Late Cretaceous localities in Alberta. The investigation of amber proves particularly informative, with carbon stable isotope ratios that are regionally consistent and furthermore conform to the larger, global-scale isotopic trend for this material, and hydrogen results that inform paleoclimatic conditions at the time of amber formation. When coupled with chemotaxonomic information from amber Fourier-transform infrared spectroscopy, the isotopic results indicate a consistent taxodioid forest composition and relatively stable environmental conditions across the three horizons that encapsulate the Danek bonebed.
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Barbeta, Adrià, Sam P. Jones, Laura Clavé, Lisa Wingate, Teresa E. Gimeno, Bastien Fréjaville, Steve Wohl i Jérôme Ogée. "Unexplained hydrogen isotope offsets complicate the identification and quantification of tree water sources in a riparian forest". Hydrology and Earth System Sciences 23, nr 4 (26.04.2019): 2129–46. http://dx.doi.org/10.5194/hess-23-2129-2019.
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Abstract. We investigated plant water sources of an emblematic refugial population of Fagus sylvatica (L.) in the Ciron river gorges in south-western France using stable water isotopes. It is generally assumed that no isotopic fractionation occurs during root water uptake, so that the isotopic composition of xylem water effectively reflects that of source water. However, this assumption has been called into question by recent studies that found that, at least at some dates during the growing season, plant water did not reflect any mixture of the potential water sources. In this context, highly resolved datasets covering a range of environmental conditions could shed light on possible plant–soil fractionation processes responsible for this phenomenon. In this study, the hydrogen (δ2H) and oxygen (δ18O) isotope compositions of all potential tree water sources and xylem water were measured fortnightly over an entire growing season. Using a Bayesian isotope mixing model (MixSIAR), we then quantified the relative contribution of water sources for F. sylvatica and Quercus robur (L.) trees. Based on δ18O data alone, both species used a mix of top and deep soil water over the season, with Q. robur using deeper soil water than F. sylvatica. The contribution of stream water appeared to be marginal despite the proximity of the trees to the stream, as already reported for other riparian forests. Xylem water δ18O could always be interpreted as a mixture of deep and shallow soil waters, but the δ2H of xylem water was often more depleted than the considered water sources. We argue that an isotopic fractionation in the unsaturated zone and/or within the plant tissues could underlie this unexpected relatively depleted δ2H of xylem water, as already observed in halophytic and xerophytic species. By means of a sensitivity analysis, we found that the estimation of plant water sources using mixing models was strongly affected by this δ2H depletion. A better understanding of what causes this isotopic separation between xylem and source water is urgently needed.
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Korotkova, T. G. "Parameters of the UNIQUAC model for describing the vapor-liquid phase equilibrium of D<sub>2</sub>-T<sub>2</sub>, D<sub>2</sub>-DT, DT-T<sub>2</sub> hydrogen isotope mixtures". Fine Chemical Technologies 17, nr 6 (24.01.2023): 459–72. http://dx.doi.org/10.32362/2410-6593-2022-17-6-459-472.
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Objectives. Determination of the parameters of the binary energy interaction of the (UNIversal QUAsiChemical) UNIQUAC model on the basis of mathematical processing of experimental literature data on the phase equilibrium of hydrogen isotopic mixtures D2-T2, D2-DT, DT-T2 to calculate the activity coefficients of the components D2, DT, and T2.Methods. The method of successive approximations was used in junction with the “from stage to stage” method, which consists in calculating a single evaporation process on a theoretical plate.Results. Equations were written for calculating the activity coefficients of hydrogen isotopes on the basis of the Sherwood theory as applied to binary D2-T2, D2-DT, DT-T2 and ternary D2-DT-T2 hydrogen isotope mixtures. The graphical dependences of the activity coefficients and separation coefficients of mixtures D2-T2, D2-DT, and DT-T2 are compared in the range of the concentration of a highly volatile component from 0 to 100 mol % at atmospheric pressure for three options: ideal mixtures; non-ideal mixtures using the Sherwood theory; non-ideal mixtures on the basis of the UNIQUAC model. The dependences of the separation coefficients a were found to be similar for all binary isotopic mixtures. However, when considering mixtures as ideal, a increases.According to Sherwood's theory, a remains a practically constant value, which is independent of the composition of the mixture. The UNIQUAC model predicts a decrease in a with an increase in the concentration of a less volatile component in the mixture. The profile of the distribution of hydrogen isotopes D2, DT, and T2 of a three-component mixture D2-DT-T2, along the height of a distillation column operating in a closed mode was calculated for three variants. It was accepted that: pressure along the height of the column is constant and equal to atmospheric 760 mm Hg. Art.; number of theoretical plates 21; concentration of components in the liquid phase on the first plate (stage), in mol %: XD₂ = 65; XDT= 10; XT₂= 25; the accuracy of calculating the composition of the vapor phase is 10-10.Conclusions. The parameters of the binary energy interaction of the UNIQUAC model of hydrogen isotopic mixtures D2-T2, D2-DT, and DT-T2 are determined. The UNIQUAC model is adequate in relation to experimental data on the coefficient of separation. Due to systematic deviations in the theoretical Sherwood and ideal models, they are not suitable for further calculations of phase equilibrium of isotopic mixtures of hydrogen D2-T2, D2-DT, DT-T2, and D2-DT-T2.
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Bonal, L., C. M. O’D Alexander, G. R. Huss, K. Nagashima, E. Quirico i P. Beck. "Hydrogen isotopic composition of the water in CR chondrites". Geochimica et Cosmochimica Acta 106 (kwiecień 2013): 111–33. http://dx.doi.org/10.1016/j.gca.2012.12.009.
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Chernov, I. P., N. N. Nikitenkov, L. N. Puchkareva, Yu R. Kolobov, M. Kröning i H. Baumbach. "Changes in isotopic composition of metals enriched in hydrogen". Russian Physics Journal 42, nr 4 (kwiecień 1999): 427–30. http://dx.doi.org/10.1007/bf02509681.
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Piani, Laurette, Kazuhide Nagashima, Noriyuki Kawasaki, Naoya Sakamoto, Ken-ichi Bajo, Yoshinari Abe, Jérôme Aléon i in. "Hydrogen Isotopic Composition of Hydrous Minerals in Asteroid Ryugu". Astrophysical Journal Letters 946, nr 2 (1.04.2023): L43. http://dx.doi.org/10.3847/2041-8213/acc393.
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Abstract Rock fragments of the Cb-type asteroid Ryugu returned to Earth by the JAXA Hayabusa2 mission share mineralogical, chemical, and isotopic properties with the Ivuna-type (CI) carbonaceous chondrites. Similar to CI chondrites, these fragments underwent extensive aqueous alteration and consist predominantly of hydrous minerals likely formed in the presence of liquid water on the Ryugu parent asteroid. Here we present an in situ analytical survey performed by secondary ion mass spectrometry from which we have estimated the D/H ratio of Ryugu’s hydrous minerals, D/HRyugu, to be [165 ± 19] × 10−6, which corresponds to δDRyugu = +59 ± 121‰ (2σ). The hydrous mineral D/HRyugu’s values for the two sampling sites on Ryugu are similar; they are also similar to the estimated D/H ratio of hydrous minerals in the CI chondrites Orgueil and Alais. This result reinforces a link between Ryugu and CI chondrites and an inference that Ryugu’s samples, which avoided terrestrial contamination, are our best proxy to estimate the composition of water at the origin of hydrous minerals in CI-like material. Based on this data and recent literature studies, the contribution of CI chondrites to the hydrogen of Earth’s surficial reservoirs is evaluated to be ∼3%. We conclude that the water responsible for the alteration of Ryugu’s rocks was derived from water ice precursors inherited from the interstellar medium; the ice partially re-equilibrated its hydrogen with the nebular H2 before being accreted on the Ryugu’s parent asteroid.
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Walter, S., A. Kock, T. Steinhoff, B. Fiedler, P. Fietzek, J. Kaiser, M. Krol i in. "Isotopic evidence for biogenic molecular hydrogen production in the Atlantic Ocean". Biogeosciences 13, nr 1 (15.01.2016): 323–40. http://dx.doi.org/10.5194/bg-13-323-2016.
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Abstract. Oceans are a net source of molecular hydrogen (H2) to the atmosphere. The production of marine H2 is assumed to be mainly biological by N2 fixation, but photochemical pathways are also discussed. We present measurements of mole fraction and isotopic composition of dissolved and atmospheric H2 from the southern and northern Atlantic between 2008 and 2010. In total almost 400 samples were taken during 5 cruises along a transect between Punta Arenas (Chile) and Bremerhaven (Germany), as well as at the coast of Mauritania.The isotopic source signatures of dissolved H2 extracted from surface water are highly deuterium-depleted and correlate negatively with temperature, showing δD values of (−629 ± 54) ‰ for water temperatures at (27 ± 3) °C and (−249 ± 88) ‰ below (19 ± 1) °C. The results for warmer water masses are consistent with the biological production of H2. This is the first time that marine H2 excess has been directly attributed to biological production by isotope measurements. However, the isotope values obtained in the colder water masses indicate that beside possible biological production, a significant different source should be considered.The atmospheric measurements show distinct differences between both hemispheres as well as between seasons. Results from the global chemistry transport model TM5 reproduce the measured H2 mole fractions and isotopic composition well. The climatological global oceanic emissions from the GEMS database are in line with our data and previously published flux calculations. The good agreement between measurements and model results demonstrates that both the magnitude and the isotopic signature of the main components of the marine H2 cycle are in general adequately represented in current atmospheric models despite a proposed source different from biological production or a substantial underestimation of nitrogen fixation by several authors.
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Walter, S., A. Kock, T. Steinhoff, B. Fiedler, P. Fietzek, J. Kaiser, M. C. Krol i in. "Isotopic evidence for biogenic molecular hydrogen production in the Atlantic Ocean". Biogeosciences Discussions 12, nr 19 (8.10.2015): 16431–77. http://dx.doi.org/10.5194/bgd-12-16431-2015.
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Abstract. Oceans are a net source of molecular hydrogen (H2) to the atmosphere. The production of marine H2 is assumed to be mainly biological by N2 fixation, but photochemical pathways are also discussed. We present measurements of mole fraction and isotopic composition of dissolved and atmospheric H2 from the southern and northern Atlantic between 2008 and 2010. In total almost 400 samples were taken during five cruises along a transect between Punta Arenas (Chile) and Bremerhaven (Germany), as well as at the coast of Mauretania. The isotopic source signatures of dissolved H2 extracted from surface water are highly deuterium-depleted and correlate negatively with temperature, showing δD values of (−629 ± 54) ‰ for water temperatures at (27 ± 3) °C and (−249 ± 88) ‰ below (19 ± 1) °C. The results for warmer water masses are consistent with biological production of H2. This is the first time that marine H2 excess has been directly attributed to biological production by isotope measurements. However, the isotope values obtained in the colder water masses indicate that beside possible biological production a significant different source should be considered. The atmospheric measurements show distinct differences between both hemispheres as well as between seasons. Results from the global chemistry transport model TM5 reproduce the measured H2 mole fractions and isotopic composition well. The climatological global oceanic emissions from the GEMS database are in line with our data and previously published flux calculations. The good agreement between measurements and model results demonstrates that both the magnitude and the isotopic signature of the main components of the marine H2 cycle are in general adequately represented in current atmospheric models despite a proposed source different from biological production or a substantial underestimation of nitrogen fixation by several authors.
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Burke, Roger A. "Possible influence of hydrogen concentration on microbial methane stable hydrogen isotopic composition". Chemosphere 26, nr 1-4 (styczeń 1993): 55–67. http://dx.doi.org/10.1016/0045-6535(93)90412-x.
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Wommack, Elizabeth A., Lisa C. Marrack, Stefania Mambelli, Joshua M. Hull i Todd E. Dawson. "Using oxygen and hydrogen stable isotopes to track the migratory movement of Sharp-shinned Hawks (Accipiter striatus) along Western Flyways of North America". PLOS ONE 15, nr 11 (17.11.2020): e0226318. http://dx.doi.org/10.1371/journal.pone.0226318.
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The large-scale patterns of movement for the Sharp-shinned Hawk (Accipiter striatus), a small forest hawk found throughout western North America, are largely unknown. However, based on field observations we set out to test the hypothesis that juvenile migratory A. striatus caught along two distinct migration routes on opposite sides of the Sierra Nevada Mountains of North America (Pacific Coast and Intermountain Migratory Flyways) come from geographically different natal populations. We applied stable isotope analysis of hydrogen (H) and oxygen (O) of feathers, and large scale models of spatial isotopic variation (isoscapes) to formulate spatially explicit predictions of the origin of the migrant birds. Novel relationships were assessed between the measured hydrogen and oxygen isotope values of feathers from A. striatus museum specimens of known origin and the isoscape modeled hydrogen and oxygen isotope values of precipitation at those known locations. We used these relationships to predict the origin regions for birds migrating along the two flyways from the measured isotope values of migrant’s feathers and the associated hydrogen and oxygen isotopic composition of precipitation where these feathers were formed. The birds from the two migration routes had overlap in their natal/breeding origins and did not differentiate into fully separate migratory populations, with birds from the Pacific Coast Migratory Flyway showing broader natal geographic origins than those from the Intermountain Flyway. The methodology based on oxygen isotopes had, in general, less predictive power than the one based on hydrogen. There was broad agreement between the two isotope approaches in the geographic assignment of the origins of birds migrating along the Pacific Coast Flyway, but not for those migrating along the Intermountain Migratory Flyway. These results are discussed in terms of their implications for conservation efforts of A. striatus in western North America, and the use of combined hydrogen and oxygen stable isotope analysis to track the movement of birds of prey on continental scales.
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Muller, Catherine L., Andy Baker, Ian J. Fairchild, Chris Kidd i Ian Boomer. "Intra-Event Trends in Stable Isotopes: Exploring Midlatitude Precipitation Using a Vertically Pointing Micro Rain Radar". Journal of Hydrometeorology 16, nr 1 (1.02.2015): 194–213. http://dx.doi.org/10.1175/jhm-d-14-0038.1.
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Abstract Annual, monthly, and daily analyses of stable isotopes in precipitation are commonly made worldwide, yet only a few studies have explored the variations occurring on short time scales within individual precipitation events, particularly at midlatitude locations. This study examines hydrogen isotope data from sequential, intra-event samples from 16 precipitation events during different seasons and a range of synoptic conditions over an 18-month period in Birmingham, United Kingdom. Precipitation events were observed simultaneously using a vertically pointing micro rain radar (MRR), which, for the first time at a midlatitude location, allowed high-resolution examination of the microphysical characteristics (e.g., rain rate, fall velocity, and drop size distributions) that may influence the local isotopic composition of rainwater. The range in the hydrogen isotope ratio (δD, where D refers to deuterium) in 242 samples during 16 events was from −87.0‰ to +9.2‰, while the largest variation observed in a single event was 55.4‰. In contrast to previous work, the results indicate that some midlatitude precipitation events do indeed show significant intra-event trends that are strongly influenced by precipitation processes and parameters such as rain rate, melting-level height, and droplet sizes. Inverse relationships between rain rate and isotopic composition are observed, representing an example of a local type of “amount effect,” a still poorly understood process occurring at different scales. For these particular events, the mean δ value may therefore not provide all the relevant information. This work has significance for the testing and development of isotope-enabled cloud-resolving models and land surface models at higher resolutions, and it provides improved insights into a range of environmental processes that are influenced by subsampled precipitation events.
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FERRON, FRANCISCO ADOLFO, RONALDO TORMA BERNARDO i JEFFERSON CARDIA SIMÕES. "Isótopos Estáveis e Química Iônica da Cobertura Glacial da Ilha do Rei George (Shetlands do Sul, Antártica) como Indicadores de Parâmetros Ambientais". Pesquisas em Geociências 28, nr 2 (31.12.2001): 343. http://dx.doi.org/10.22456/1807-9806.20308.
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Hydrogen and oxygen stable isotopes and anionic concentration (sulphates, chlorides and nitrates) in snow and ice from King George Island are presented. Isotopic and chemical composition are preserved in the uppermost part of the ice cap (first meters) providing informations about some environmental parameters as the origin of precipitation and particles (impurities) e its distribution, atmospheric circulation and the physics processes occurring in the ice pack.
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Yang, Kunhua, Guilin Han, Man Liu, Xiaoqiang Li, Jinke Liu i Qian Zhang. "Spatial and Seasonal Variation of O and H Isotopes in the Jiulong River, Southeast China". Water 10, nr 11 (17.11.2018): 1677. http://dx.doi.org/10.3390/w10111677.
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The stable isotope technique of oxygen and hydrogen (δ18O and δ2H) and deuterium excess (d-excess) was used to investigate distribution characteristics in June 2017 and January 2018 in the Jiulong River, southeast China. The results revealed that (1) seasonal isotopic composition was mainly controlled by precipitation. It enriched lighter water isotopes in winter more than in summer because of the aggravating effect of low temperature and great rainfall. (2) Spatial distribution of the North, West, and South River showed increasing enrichment of heavy isotopes in that order. In the high-flow season, the continuous high-flow made δ18O and δ2H homogeneous, despite increasing weak evaporation along water-flow paths in the West and South River. In the low-flow season, there was a decreasing trend in the middle and lower reaches of the North and West main stream and an increasing trend in the South River. (3) O and H isotopic geochemistry exhibited natural and anthropogenic influence in hydrological process, such as heavy rainfall and cascade reservoirs. The results showed that O and H isotopes are indeed useful tracers of the water cycle.
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Bahlmann, Enno, Christian Stolle, Ingo Weinberg, Richard Seifert, Detlef E. Schulz-Bull i Walter Michaelis. "Isotopic composition of polyhalomethanes from marine macrophytes – systematic effects of the halogen substituents on isotopic composition". Environmental Chemistry 12, nr 4 (2015): 504. http://dx.doi.org/10.1071/en14210.
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Environmental context Once released to the atmosphere, halocarbons are involved in key chemical reactions. Stable carbon isotope measurements of halocarbons can provide valuable information on their sources and fate in the atmosphere. Here, we report δ13C values of 13 polyhalomethanes released from brown algae, which may provide a basis for inferring their sources and fate in future studies. Abstract Halocarbons are important vectors of reactive halogens to the atmosphere, where the latter participate in several key chemical processes. An improved understanding of the biogeochemical controls of the production–destruction equilibrium on halocarbons is of vital importance to address potential future changes in their fluxes to the atmosphere. Carbon stable isotope ratios of halocarbons could provide valuable additional information on their sources and fate that cannot be derived from mixing ratios alone. We determined the δ13C values of 13 polyhalomethanes from three brown algae species (Laminaria digitata, Fucus vesiculosus, Fucus serratus) and one seagrass species (Zostera noltii). The δ13C values were determined in laboratory incubations under variable environmental conditions of light, water levels (to simulate tidal events) and addition of hydrogen peroxide (H2O2). The δ13C values of the polyhalomethanes ranged from –42.2 ‰ (±3.5s.d.) for CHCl3 to 6.9 ‰ (±4.5) for CHI2Br and showed a systematic effect of the halogen substituents that could empirically be described in terms of linear free energy relationships. We further observed an enrichment in the δ13C of the polyhalomethanes with decreasing polyhalomethane yield that is attributed to the competing formation of halogenated ketones. Though variable, the isotopic composition of polyhalomethanes may provide useful additional information to discriminate between marine polyhalomethane sources.
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Diao, Haoyu, Philipp Schuler, Gregory R. Goldsmith, Rolf T. W. Siegwolf, Matthias Saurer i Marco M. Lehmann. "Technical note: On uncertainties in plant water isotopic composition following extraction by cryogenic vacuum distillation". Hydrology and Earth System Sciences 26, nr 22 (17.11.2022): 5835–47. http://dx.doi.org/10.5194/hess-26-5835-2022.
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Abstract. Recent studies have challenged the interpretation of plant water isotopes obtained through cryogenic vacuum distillation (CVD) based on observations of a large 2H fractionation. These studies have hypothesized the existence of an H-atom exchange between water and organic tissue during CVD extraction with the magnitude of H exchange related to relative water content of the sample; however, clear evidence is lacking. Here, we systematically tested the uncertainties in the isotopic composition of CVD-extracted water by conducting a series of incubation and rehydration experiments using isotopically depleted water, water at natural isotope abundance, woody materials with exchangeable H, and organic materials without exchangeable H (cellulose triacetate and caffeine). We show that the offsets between hydrogen and oxygen isotope ratios and expected reference values (Δ2H and Δ18O) have inversely proportional relationships with the absolute amount of water being extracted, i.e. the lower the water amount, the higher the Δ2H and Δ18O. However, neither Δ2H nor Δ18O values, were related to sample relative water content. The Δ2H pattern was more pronounced for materials with exchangeable H atoms than with non-exchangeable H atoms. This is caused by the combined effect of H exchange during the incubation of materials in water and isotopic enrichments during evaporation and sublimation that depend on absolute water amount. The H exchange during CVD extraction itself was negligible. Despite these technical issues, we observed that the water amount-dependent patterns were much less pronounced for samples at natural isotope abundance and particularly low when sufficiently high amounts of water were extracted (>600 µL). Our study provides new insights into the mechanisms causing isotope fractionation during CVD extraction of water. The methodological uncertainties can be controlled if large samples of natural isotope abundance are used in ecohydrological studies.
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Xia, Chengcheng, Guodong Liu, Yuchuan Meng i Ke Chen. "Comparison of Intra-Event Characteristics of Hydrogen and Oxygen Stable Isotopes between Rainfall and Throughfall and the Effects of Pre-Event Precipitation". Forests 14, nr 8 (9.08.2023): 1603. http://dx.doi.org/10.3390/f14081603.
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The isotopic composition of precipitation provides valuable information about its source and transportation. However, raindrops interact with vegetation before reaching the earth’s surface, leading to isotopic changes in the infiltrating water. Comparing isotopic composition between rainfall and throughfall helps to understand canopy processes and their impact on isotopic variation. Based on observational data collected during the periods of July 2019, July–August 2020, and July–August 2021 in a planted forest located in the southwest monsoon region of China, this study examines hydrogen and oxygen isotopes in rainfall and throughfall at event and intra-event scales, and investigates the effects of pre-event precipitation (PEP) on the isotopic composition. The results indicate that during the initial stage of precipitation, δ18O was enriched in rainfall and it presented a dilution effect gradually, while the d-excess exhibits a low initial value followed by an increasing trend. The difference in δ18O between throughfall and rainfall initially increased and subsequently converged around 0, whereas the difference in d-excess experiences a decreasing phase, followed by an increasing phase, and finally a decreasing phase. Canopy interception led to a lag effect during the early stage of precipitation; the forest exhibited higher water vapor content compared to open land in the intermediate stage, which reduced the degree of non-equilibrium fractionation in throughfall, and the flow pathway enhanced in the later stage. Evaporation processes become more prominent as precipitation intensity weakens. The rainfall and throughfall were influenced by distinct meteorological factors in different precipitation events, and the role of the forest canopy varied across different precipitation periods. PEP was found to augment the intercept and slope of the linear relationship between the H-O isotopic composition of throughfall and rainfall. This pre-event effect also contributes to heightened fluctuations in the δ18O and d-excess values during subsequent precipitation events. The findings contribute to understanding water dynamics, vegetation interception, and mechanisms governing water input in forested areas during precipitation events, which provides valuable insights for analyzing factors influencing water movement in forest ecosystems.
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Fedotov, Andrey, Ruslan Gnatovsky, Vadim Blinov, Maria Sakirko, Valentina Domysheva i Olga Stepanova. "The Current Oxygen and Hydrogen Isotopic Status of Lake Baikal". Water 13, nr 23 (6.12.2021): 3476. http://dx.doi.org/10.3390/w13233476.
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This study revises the δ18O and δ2H status of Lake Baikal. The mean values of δ18O and δ2H varied from −15.9 to −15.5‰ and from −123.2 to 122.2‰, respectively, for the past 30 yr. The isotopic composition of the lake remained more ‘‘light” compared to the regional precipitation and rivers inflows. The isotopic composition of the lake has begun to change since ca.1920 after the Little Ice Age; however, Lake Baikal still has not reached the isotopically steady state in the present. The calculated composition of the steady-state should be −12.3‰ for δ18O and −103.6‰ for δ2H. If regional climate parameters do not change dramatically, Lake Baikal will reach these values in ca. 226 yr. Based on isotopic fingerprints of the upper (0 to 150 m) and near-bottom layers (ca. 150 m from the bottom floor), the renewal in the southern and central basins of Lake Baikal has occurred recently compared to the northern Baikal basin, and the size of the mixing-cell of downwelling is close to 30 km.
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Whitledge, Gregory W., Brett M. Johnson i Patrick J. Martinez. "Stable hydrogen isotopic composition of fishes reflects that of their environment". Canadian Journal of Fisheries and Aquatic Sciences 63, nr 8 (1.08.2006): 1746–51. http://dx.doi.org/10.1139/f06-076.
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Otolith microchemistry and isotopic analyses have emerged as effective techniques for providing insights into fish environmental history that are difficult to obtain by other means. Stable hydrogen isotope ratio (2H/1H or D/H, expressed as δD) is a possible environmental marker that has not been employed in fish provenance research, although it has been applied as a natural tracer of terrestrial organism migrations. We illustrate the potential of δD to serve as a new natural marker of fish environmental history by demonstrating that significant linear relationships (r2 ≥ 0.97) exist between fish otolith and muscle δD and δD of waters that fish inhabit. Differences between mean water δD and both muscle and otolith δD were not significantly correlated with fish total length and were not significantly different among species, indicating that water–fish δD relationships are consistent across fish sizes and species. High r2 values for regressions of otolith and muscle δD on water δD for fishes inhabiting locations with diverse thermal regimes suggest that relationships between water and fish δD are not strongly affected by water temperature. Demonstration that fish δD clearly reflects water δD provides a foundation for future research to reconstruct fish movement among locations with distinct δD signatures.
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Paul, Alexia, Christine Hatté, Lucie Pastor, Yves Thiry, Françoise Siclet i Jérôme Balesdent. "Hydrogen dynamics in soil organic matter as determined by <sup>13</sup>C and <sup>2</sup>H labeling experiments". Biogeosciences 13, nr 24 (15.12.2016): 6587–98. http://dx.doi.org/10.5194/bg-13-6587-2016.
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Abstract. Understanding hydrogen dynamics in soil organic matter is important to predict the fate of 3H in terrestrial environments. One way to determine hydrogen fate and to point out processes is to examine the isotopic signature of the element in soil. However, the non-exchangeable hydrogen isotopic signal in soil is complex and depends on the fate of organic compounds and microbial biosyntheses that incorporate water-derived hydrogen. To decipher this complex system and to understand the close link between hydrogen and carbon cycles, we followed labeled hydrogen and labeled carbon throughout near-natural soil incubations. We performed incubation experiments with three labeling conditions: 1 – 13C2H double-labeled molecules in the presence of 1H2O; 2 – 13C-labeled molecules in the presence of 2H2O; 3 – no molecule addition in the presence of 2H2O. The preservation of substrate-derived hydrogen after 1 year of incubation (ca. 5 % in most cases) was lower than the preservation of substrate-derived carbon (30 % in average). We highlighted that 70 % of the C–H bonds are broken during the degradation of the molecule, which permits the exchange with water hydrogen. Added molecules are used more for trophic resources. The isotopic composition of the non-exchangeable hydrogen was mainly driven by the incorporation of water hydrogen during microbial biosynthesis. It is linearly correlated with the amount of carbon that is degraded in the soil. The quantitative incorporation of water hydrogen in bulk material and lipids demonstrates that non-exchangeable hydrogen exists in both organic and mineral-bound forms. The proportion of the latter depends on soil type and minerals. This experiment quantified the processes affecting the isotopic composition of non-exchangeable hydrogen, and the results can be used to predict the fate of tritium in the ecosystem or the water deuterium signature in organic matter.
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Swart, Peter K. "The oxygen and hydrogen isotopic composition of the Black Sea". Deep Sea Research Part A. Oceanographic Research Papers 38 (styczeń 1991): S761—S772. http://dx.doi.org/10.1016/s0198-0149(10)80008-1.
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Bell, David R., i Phillip D. Ihinger. "The isotopic composition of hydrogen in nominally anhydrous mantle minerals". Geochimica et Cosmochimica Acta 64, nr 12 (czerwiec 2000): 2109–18. http://dx.doi.org/10.1016/s0016-7037(99)00440-8.
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Piani, Laurette, i Yves Marrocchi. "Hydrogen isotopic composition of water in CV-type carbonaceous chondrites". Earth and Planetary Science Letters 504 (grudzień 2018): 64–71. http://dx.doi.org/10.1016/j.epsl.2018.09.031.
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Gounelle, Matthieu, Cécile Engrand, Olivier Alard, Philip A. Bland, Michael E. Zolensky, Sara S. Russell i Jean Duprat. "Hydrogen isotopic composition of water from fossil micrometeorites in howardites". Geochimica et Cosmochimica Acta 69, nr 13 (lipiec 2005): 3431–43. http://dx.doi.org/10.1016/j.gca.2004.12.021.
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