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Journal articles on the topic 'Isotope signature'

Author: Grafiati

Published: 4 June 2021

Last updated: 3 February 2022

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1

Emmanuel, S., J. A. Schuessler, J. Vinther, A. Matthews, and F. von Blanckenburg. "Iron isotope fractionation in marine invertebrates in near shore environments." Biogeosciences Discussions 11, no. 4 (2014): 5533–55. http://dx.doi.org/10.5194/bgd-11-5533-2014.

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Abstract. Chitons (Mollusca) are marine invertebrates that produce radula (teeth or rasping tongue) containing high concentrations of biomineralized magnetite and other iron bearing minerals. As Fe isotope signatures are influenced by redox processes and biological fractionation, Fe isotopes in chiton radula might be expected to provide an effective tracer of ambient oceanic conditions and biogeochemical cycling. Here, in a pilot study to measure Fe isotopes in marine invertebrates, we examine Fe isotopes in modern marine chiton radula collected from different locations in the Atlantic and Pac

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Emmanuel, S., J. A. Schuessler, J. Vinther, A. Matthews, and F. von Blanckenburg. "A preliminary study of iron isotope fractionation in marine invertebrates (chitons, Mollusca) in near-shore environments." Biogeosciences 11, no. 19 (2014): 5493–502. http://dx.doi.org/10.5194/bg-11-5493-2014.

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Abstract. Chitons (Mollusca) are marine invertebrates that produce radulae (teeth or rasping tongues) containing high concentrations of biomineralized magnetite and other iron-bearing minerals. As Fe isotope signatures are influenced by redox processes and biological fractionation, Fe isotopes in chiton radulae might be expected to provide an effective tracer of ambient oceanic conditions and biogeochemical cycling. Here, in a pilot study to measure Fe isotopes in marine invertebrates, we examine Fe isotopes in modern marine chiton radulae collected from different locations in the Atlantic and

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3

MacAvoy, Stephen E., Stephen A. Macko, and Lynne S. Arneson. "Growth versus metabolic tissue replacement in mouse tissues determined by stable carbon and nitrogen isotope analysis." Canadian Journal of Zoology 83, no. 5 (2005): 631–41. http://dx.doi.org/10.1139/z05-038.

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Stable-isotope signatures in animal tissues presumably reflect the local food web. However, that assumption may be complicated by differential nutrient routing, fractionation, and the possibility that large organisms are not in isotopic equilibrium with seasonally available food sources. Additionally, the rate at which organisms incorporate the isotopic signature of a food is largely unknown. In this study we assessed the rate of carbon- and nitrogen-isotope turnover in liver, muscle, and blood in mice (Mus musculus L., 1758) following a diet change. We report the proportion of tissue turnover

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4

Abiye, Tamiru A., Molla B. Demlie та Haile Mengistu. "An Overview of Aquifer Physiognomies and the δ18O and δ2H Distribution in the South African Groundwaters". Hydrology 8, № 2 (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 isoto

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5

Meister, Patrick, and Carolina Reyes. "The Carbon-Isotope Record of the Sub-Seafloor Biosphere." Geosciences 9, no. 12 (2019): 507. http://dx.doi.org/10.3390/geosciences9120507.

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Sub-seafloor microbial environments exhibit large carbon-isotope fractionation effects as a result of microbial enzymatic reactions. Isotopically light, dissolved inorganic carbon (DIC) derived from organic carbon is commonly released into the interstitial water due to microbial dissimilatory processes prevailing in the sub-surface biosphere. Much stronger carbon-isotope fractionation occurs, however, during methanogenesis, whereby methane is depleted in 13C and, by mass balance, DIC is enriched in 13C, such that isotopic distributions are predominantly influenced by microbial metabolisms invo

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6

Jiménez-Rodríguez, César Dionisio, Miriam Coenders-Gerrits, Jochen Wenninger, Adriana Gonzalez-Angarita, and Hubert Savenije. "Contribution of understory evaporation in a tropical wet forest during the dry season." Hydrology and Earth System Sciences 24, no. 4 (2020): 2179–206. http://dx.doi.org/10.5194/hess-24-2179-2020.

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Abstract. Tropical wet forests are complex ecosystems with a large number of plant species. These environments are characterized by a high water availability throughout the whole year and a complex canopy structure. However, how the different sections of the canopy contribute to total evaporation is poorly understood. The aim of this work is to estimate the total evaporation flux and differentiate the contribution among canopy layers of a tropical wet forest in Costa Rica. The fluxes were monitored during the dry season by making use of the energy balance to quantify the fluxes and stable wate

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7

FELITSYN, SERGEI B., and ALEXANDER P. GUBANOV. "Nd isotope composition of early Cambrian discrete basins." Geological Magazine 139, no. 2 (2002): 159–69. http://dx.doi.org/10.1017/s0016756801006252.

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A Nd isotope map of early Cambrian epeiric basins has been inferred from the Nd isotopic signature recorded in phosphatic Small Shelly Fossils. The most radiogenic εNd(t) values characterize water reservoirs along the Avalonian and Cadomian belts, while εNd(t) values of −10 to −20 were obtained in Laurentia and East Gondwanan Australia and China. Such a distribution of Nd isotope signatures results from the different provenance of early Cambrian epeiric seas: juvenile magmatic arcs and/or cordilleran for Mongolia, Siberia, Iberia and adjacent terranes, and cratonic sources for Laurentia and Ea

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8

Guo, Rong, Shengjie Wang, Mingjun Zhang, et al. "Stable Hydrogen and Oxygen Isotope Characteristics of Bottled Water in China: A Consideration of Water Source." Water 11, no. 5 (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 wa

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9

Stevenson, R. K., X. W. Meng, and C. Hillaire-Marcel. "Impact of melting of the Laurentide Ice Sheet on sediments from the upper continental slope off southeastern Canada: evidence from Sm–Nd isotopesThis article is one of a series of papers published in this Special Issue on the theme Polar Climate Stability Network." Canadian Journal of Earth Sciences 45, no. 11 (2008): 1243–52. http://dx.doi.org/10.1139/e08-031.

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We present new Sm–Nd isotope data for sediments from a core located on the continental slope of the St. Pierre Bank of Canada’s east coast. The Nd analyses indicate that the sediments were derived from two principal sources: the North American Shield that yields an average early Proterozoic isotopic signature and a younger Proterozoic signature attributed to Appalachian crustal sources. The Appalachian-sourced sediments predominated during the last glacial maximum (LGM) and were associated with low sedimentation rates (<30 cm/ka), with the exception of a strong North American Shield signatu

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10

Weng, Yongbiao, Aina Johannessen, and Harald Sodemann. "High-resolution stable isotope signature of a land-falling atmospheric river in southern Norway." Weather and Climate Dynamics 2, no. 3 (2021): 713–37. http://dx.doi.org/10.5194/wcd-2-713-2021.

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Abstract. Heavy precipitation at the west coast of Norway is often connected to elongated meridional structures of high integrated water vapour transport known as atmospheric rivers (ARs). Here we present high-resolution measurements of stable isotopes in near-surface water vapour and precipitation during a land-falling AR in southwestern Norway on 7 December 2016. In our analysis, we aim to identify the influences of moisture source conditions, weather system characteristics, and post-condensation processes on the isotope signal in near-surface water vapour and precipitation. A total of 71 pr

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Schumacher, M., R. E. M. Neubert, H. A. J. Meijer, et al. "Oxygen isotopic signature of CO<sub>2</sub> from combustion processes." Atmospheric Chemistry and Physics Discussions 8, no. 6 (2008): 18993–9034. http://dx.doi.org/10.5194/acpd-8-18993-2008.

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Abstract. For a comprehensive understanding of the global carbon cycle precise knowledge of all processes is necessary. Stable isotope (13C and 18O) abundances provide information for the qualification and the quantification of the diverse source and sink processes. This study focuses on the δ18O signature of CO2 from combustion processes, which are widely present both naturally (wild fires), and human induced (fossil fuel combustion, biomass burning) in the carbon cycle. All these combustion processes use atmospheric oxygen, of which the isotopic signature is assumed to be constant with time

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12

Zahajská, Petra, Rosine Cartier, Sherilyn C. Fritz, et al. "Impact of Holocene climate change on silicon cycling in Lake 850, Northern Sweden." Holocene 31, no. 10 (2021): 1582–92. http://dx.doi.org/10.1177/09596836211025973.

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Diatom-rich sediment in a small subarctic lake (Lake 850) was investigated in a 9400 cal. yr BP sediment record in order to explore the impact of Holocene climate evolution on silicon cycling. Diatom stable silicon isotopes ([Formula: see text]) and biogenic silica (BSi) indicate that high BSi concentrations in sediment throughout the Holocene are associated with a lighter Si isotope source of dissolved silica (DSi), such as groundwater or freshly weathered primary minerals. Furthermore, higher BSi concentrations were favoured during the mid-Holocene by low detrital inputs and possibly a longe

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13

Leketa, Khahliso, and Tamiru Abiye. "Using Environmental Tracers to Characterize Groundwater Flow Mechanisms in the Fractured Crystalline and Karst Aquifers in Upper Crocodile River Basin, Johannesburg, South Africa." Hydrology 8, no. 1 (2021): 50. http://dx.doi.org/10.3390/hydrology8010050.

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Environmental isotope tracers were applied in the Upper Crocodile River Basin, Johannesburg, South Africa, to understand the groundwater recharge conditions, flow mechanisms and interactions between surface and subsurface water. Stable isotope analysis indicated that recharge into the fractured quartzite aquifer occurs through direct mechanisms. The high variability in the stable isotope signature of temporal samples from Albert Farm spring indicated the importance of multiple samples for groundwater characterization, and that using a single sample may be yielding biased conclusions. The obser

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14

Helsen, M. M., R. S. W. Van de Wal, and M. R. Van den Broeke. "The Isotopic Composition of Present-Day Antarctic Snow in a Lagrangian Atmospheric Simulation*." Journal of Climate 20, no. 4 (2007): 739–56. http://dx.doi.org/10.1175/jcli4027.1.

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Abstract The isotopic composition of present-day Antarctic snow is simulated for the period September 1980–August 2002 using a Rayleigh-type isotope distillation model in combination with backward trajectory calculations with 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40) data as meteorological input. Observed spatial isotopic gradients are correctly reproduced, especially in West Antarctica and in the coastal areas. However, isotopic depletion of snow on the East Antarctic plateau is underestimated, a problem that is also observed in general circulation

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15

Kristensen, D. K., E. Kristensen, M. C. Forchhammer, A. Michelsen, and N. M. Schmidt. "Arctic herbivore diet can be inferred from stable carbon and nitrogen isotopes in C3 plants, faeces, and wool." Canadian Journal of Zoology 89, no. 10 (2011): 892–99. http://dx.doi.org/10.1139/z11-073.

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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 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

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16

Schumacher, M., R. A. Werner, H. A. J. Meijer, et al. "Oxygen isotopic signature of CO<sub>2</sub> from combustion processes." Atmospheric Chemistry and Physics 11, no. 4 (2011): 1473–90. http://dx.doi.org/10.5194/acp-11-1473-2011.

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Abstract. For a comprehensive understanding of the global carbon cycle precise knowledge of all processes is necessary. Stable isotope (13C and 18O) abundances provide information for the qualification and the quantification of the diverse source and sink processes. This study focuses on the δ18O signature of CO2 from combustion processes, which are widely present both naturally (wild fires), and human induced (fossil fuel combustion, biomass burning) in the carbon cycle. All these combustion processes use atmospheric oxygen, of which the isotopic signature is assumed to be constant with time

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17

Winterholler, B., P. Hoppe, J. Huth, S. Foley, and M. O. Andreae. "Sulfur isotope analyses of individual aerosol particles in the urban aerosol at a central European site (Mainz, Germany)." Atmospheric Chemistry and Physics Discussions 8, no. 3 (2008): 9347–404. http://dx.doi.org/10.5194/acpd-8-9347-2008.

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Abstract. Sulfur isotope analysis of atmospheric aerosols is a well established tool for identifying sources of sulfur in the atmosphere, estimating emission factors, and tracing the spread of sulfur from anthropogenic sources through ecosystems. Conventional gas mass spectrometry averages the isotopic compositions of several different types of sulfur aerosol particles, and therefore masks the individual isotopic signatures. In contrast, the new single particle technique presented here determines the isotopic signature of the individual particles. Primary aerosol particles retain the original

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18

Benettin, Paolo, Till H. M. Volkmann, Jana von Freyberg, et al. "Effects of climatic seasonality on the isotopic composition of evaporating soil waters." Hydrology and Earth System Sciences 22, no. 5 (2018): 2881–90. http://dx.doi.org/10.5194/hess-22-2881-2018.

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Abstract. Stable water isotopes are widely used in ecohydrology to trace the transport, storage, and mixing of water on its journey through landscapes and ecosystems. Evaporation leaves a characteristic signature on the isotopic composition of the water that is left behind, such that in dual-isotope space, evaporated waters plot below the local meteoric water line (LMWL) that characterizes precipitation. Soil and xylem water samples can often plot below the LMWL as well, suggesting that they have also been influenced by evaporation. These soil and xylem water samples frequently plot along line

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19

Sinha, B. W., P. Hoppe, J. Huth, S. Foley, and M. O. Andreae. "Sulfur isotope analyses of individual aerosol particles in the urban aerosol at a central European site (Mainz, Germany)." Atmospheric Chemistry and Physics 8, no. 23 (2008): 7217–38. http://dx.doi.org/10.5194/acp-8-7217-2008.

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Abstract. Sulfur isotope analysis of atmospheric aerosols is a well established tool for identifying sources of sulfur in the atmosphere, estimating emission factors, and tracing the spread of sulfur from anthropogenic sources through ecosystems. Conventional gas mass spectrometry averages the isotopic compositions of several different types of sulfur aerosol particles, and therefore masks the individual isotopic signatures. In contrast, the new single particle technique presented here determines the isotopic signature of the individual particles. Primary aerosol particles retain the original

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Nan, Yi, Lide Tian, Zhihua He, Fuqiang Tian, and Lili Shao. "The value of water isotope data on improving process understanding in a glacierized catchment on the Tibetan Plateau." Hydrology and Earth System Sciences 25, no. 6 (2021): 3653–73. http://dx.doi.org/10.5194/hess-25-3653-2021.

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Abstract. This study integrated a water isotope module into the hydrological model THREW (Tsinghua Representative Elementary Watershed) which has been successfully used in high and cold regions. Signatures of oxygen stable isotope (18O) of different water inputs and stores were simulated coupling with the simulations of runoff generation. Isotope measurements of precipitation water samples and assumed constant isotope signature of ice meltwater were used to force the isotope module. Isotope signatures of water stores such as snowpack and subsurface water were updated by an assumed completely m

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Lin, Mang, Xiaolin Zhang, Menghan Li, et al. "Five-S-isotope evidence of two distinct mass-independent sulfur isotope effects and implications for the modern and Archean atmospheres." Proceedings of the National Academy of Sciences 115, no. 34 (2018): 8541–46. http://dx.doi.org/10.1073/pnas.1803420115.

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The signature of mass-independent fractionation of quadruple sulfur stable isotopes (S-MIF) in Archean rocks, ice cores, and Martian meteorites provides a unique probe of the oxygen and sulfur cycles in the terrestrial and Martian paleoatmospheres. Its mechanistic origin, however, contains some uncertainties. Even for the modern atmosphere, the primary mechanism responsible for the S-MIF observed in nearly all tropospheric sulfates has not been identified. Here we present high-sensitivity measurements of a fifth sulfur isotope, stratospherically produced radiosulfur, along with all four stable

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22

Kreuzer-Martin, Helen W., and Kristin H. Jarman. "Stable Isotope Ratios and Forensic Analysis of Microorganisms." Applied and Environmental Microbiology 73, no. 12 (2007): 3896–908. http://dx.doi.org/10.1128/aem.02906-06.

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ABSTRACT In the aftermath of the anthrax letters of 2001, researchers have been exploring various analytical signatures for the purpose of characterizing the production environment of microorganisms. One such signature is stable isotope ratios, which in heterotrophs, are a function of nutrient and water sources. Here we discuss the use of stable isotope ratios in microbial forensics, using as a database the carbon, nitrogen, oxygen, and hydrogen stable isotope ratios of 247 separate cultures of Bacillus subtilis 6051 spores produced on a total of 32 different culture media. In the context of u

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23

Seeger, Stefan, and Markus Weiler. "Temporal dynamics of tree xylem water isotopes: in situ monitoring and modeling." Biogeosciences 18, no. 15 (2021): 4603–27. http://dx.doi.org/10.5194/bg-18-4603-2021.

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Abstract. We developed a setup for a fully automated, high-frequency in situ monitoring system of the stable water isotope deuterium and 18O in soil water and tree xylem. The setup was tested for 12 weeks within an isotopic labeling experiment during a large artificial sprinkling experiment including three mature European beech (Fagus sylvatica) trees. Our setup allowed for one measurement every 12–20 min, enabling us to obtain about seven measurements per day for each of our 15 in situ probes in the soil and tree xylem. While the labeling induced an abrupt step pulse in the soil water isotopi

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Wang, Hai Xia, Yu Liu, Ling Liu, Hui Ming Bao, and Bao Zhan Liu. "Effects of Nutritional Conditions on the Stable Carbon and Nitrogen Isotope of Microalgae." Advanced Materials Research 765-767 (September 2013): 2894–98. http://dx.doi.org/10.4028/www.scientific.net/amr.765-767.2894.

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Carbon and nitrogen stable isotopes were studied among different groups and species of marine phytoplankton on the aspect of growth phase and nutrient conditions. Three investigated algal species which represent the Chlorophyceae, Dinophyceae and Desmokontae classes were grown in batch monocultures and analysed for δ13C and δ15N in both exponential and stationary phase. For all the cultured species, δ13C signatures range from 24.77 (A.carterae) to 17.10 (P. micans) as well as δ15N range from-15.66(P. helgolandica) to 14.40(P. helgolandica).These three species (Platymonas helgolandicavar. tsing

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Wang, Hai Xia, Yu Liu, Ling Liu, Hui Ming Bao, and Bao Zhan Liu. "Effects of Nutritional Conditions on the Stable Carbon and Nitrogen Isotope of Microalgae." Advanced Materials Research 779-780 (September 2013): 1678–82. http://dx.doi.org/10.4028/www.scientific.net/amr.779-780.1678.

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Carbon and nitrogen stable isotopes were studied among different groups and species of marine phytoplankton on the aspect of growth phase and nutrient conditions. Three investigated algal species which represent the Chlorophyceae, Dinophyceae and Desmokontae classes were grown in batch monocultures and analysed for δ13C and δ15N in both exponential and stationary phase. For all the cultured species, δ13C signatures range from 24.77 (A.carterae) to 17.10 (P. micans) as well as δ15N range from-15.66(P. helgolandica) to 14.40(P. helgolandica).These three species (Platymonas helgolandicavar. tsing

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Ford, William, Mark R. Williams, Megan B. Young, Kevin W. King, and Eric Fischer. "Assessing Intra-Event Phosphorus Dynamics in Drainage Water Using Phosphate Stable Oxygen Isotopes." Transactions of the ASABE 61, no. 4 (2018): 1379–92. http://dx.doi.org/10.13031/trans.12804.

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Abstract. Quantifying fluxes and pathways of dissolved reactive phosphorus (DRP) in tile-drained landscapes has been hampered by a lack of measurements that are sensitive to P fate and transport processes. One potential tool to help understand these dynamics is the oxygen isotope signature of phosphate (d18OPO4); however, its potential benefits and limitations are not well understood for intra-event dynamics at the field scale. The objectives of this study were to quantify intra-event variability of d18OPO4 signatures in tile drainage water and assess the efficacy of d18OPO4 to elucidate mecha

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Volkmann, T. H. M., and M. Weiler. "Continual in-situ monitoring of pore water stable isotopes in the subsurface." Hydrology and Earth System Sciences Discussions 10, no. 11 (2013): 13293–331. http://dx.doi.org/10.5194/hessd-10-13293-2013.

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Abstract. The stable isotope signature of pore water provides an integral fingerprint of water origin, flow path, transport processes, and residence times and can thus serve as a powerful tracer of hydrological processes in the unsaturated and saturated zone. However, the full potential of stable isotopes to quantitatively characterize subsurface water dynamics is yet unfolded due to the difficulty in obtaining extensive detailed and continual measurements of spatiotemporally variable pore water signatures. With the development of field-deployable laser-based isotope analyzers, such measuremen

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Findlay, Alyssa J., Valeria Boyko, André Pellerin, et al. "Sulfide oxidation affects the preservation of sulfur isotope signals." Geology 47, no. 8 (2019): 739–43. http://dx.doi.org/10.1130/g46153.1.

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Abstract The accumulation of oxygen in Earth’s atmosphere and oceans in the late Archean had profound implications for the planet’s biogeochemical evolution. Oxygen impacts sulfur cycling through the oxidation of sulfide minerals and the production of sulfate for microbial sulfate reduction (MSR). The isotopic signature of sulfur species preserved in the geologic record is affected by the prevailing biological and chemical processes and can therefore be used to constrain past oxygen and sulfate concentrations. Here, in a study of a late Archean analogue, we find that the sulfur isotopic signat

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Peters, Stefan T. M., Narges Alibabaie, Andreas Pack, et al. "Triple oxygen isotope variations in magnetite from iron-oxide deposits, central Iran, record magmatic fluid interaction with evaporite and carbonate host rocks." Geology 48, no. 3 (2019): 211–15. http://dx.doi.org/10.1130/g46981.1.

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Abstract Oxygen isotope ratios in magnetite can be used to study the origin of iron-oxide ore deposits. In previous studies, only 18O/16O ratios of magnetite were determined. Here, we report triple O isotope data (17O/16O and 18O/16O ratios) of magnetite from the iron-oxide–apatite (IOA) deposits of the Yazd and Sirjan areas in central Iran. In contrast to previous interpretations of magnetite from similar deposits, the triple O isotope data show that only a few of the magnetite samples potentially record isotopic equilibrium with magma or with pristine magmatic water (H2O). Instead, the data

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Röckmann, T., J. Kaiser, and C. A. M. Brenninkmeijer. "The isotopic fingerprint of the pre-industrial and the anthropogenic N<sub>2</sub>O source." Atmospheric Chemistry and Physics Discussions 2, no. 6 (2002): 2021–43. http://dx.doi.org/10.5194/acpd-2-2021-2002.

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Abstract. We have performed high-precision measurements of the 18O and position dependent 15N isotopic composition of N2O from Antarctic firn air samples. By comparing these data to simulations carried out with a firn air diffusion model, we have reconstructed the temporal evolution of the N2O isotope signatures since pre-industrial times. The heavy isotope content of atmospheric N2O is presently decreasing for all signatures at rates of about -0.038%o yr -1 for 1d15N, -0.044%o yr -1 for 2d15N and -0.025%o yr -1 for d18O. The total decrease since pre-industrial times is estimated to be about -

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Röckmann, T., J. Kaiser, and C. A. M. Brenninkmeijer. "The isotopic fingerprint of the pre-industrial and the anthropogenic N<sub>2</sub>O source." Atmospheric Chemistry and Physics 3, no. 2 (2003): 315–23. http://dx.doi.org/10.5194/acp-3-315-2003.

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Abstract. We have performed high-precision measurements of the 18O and position dependent 15N isotopic composition of N2O from Antarctic firn air samples. By comparing these data to simulations carried out with a firn air diffusion model, we have reconstructed the temporal evolution of the N2O isotope signatures since pre-industrial times. The heavy isotope content of atmospheric N2O is presently decreasing for all signatures at rates of about -0.038 %o yr -1 for 1d15N, -0.046 %o yr -1 for 2d 15N and -0.025 %o yr -1 for d18O. The total decrease since pre-industrial times is estimated to be abo

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Matich, Philip, Michael R. Heithaus, and Craig A. Layman. "Size-based variation in intertissue comparisons of stable carbon and nitrogen isotopic signatures of bull sharks (Carcharhinus leucas) and tiger sharks (Galeocerdo cuvier)." Canadian Journal of Fisheries and Aquatic Sciences 67, no. 5 (2010): 877–85. http://dx.doi.org/10.1139/f10-037.

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Stable isotopes are important tools for understanding the trophic roles of elasmobranchs. However, whether different tissues provide consistent stable isotope values within an individual are largely unknown. To address this, the relationships among carbon and nitrogen isotope values were quantified for blood, muscle, and fin from juvenile bull sharks ( Carcharhinus leucas ) and blood and fin from large tiger sharks ( Galeocerdo cuvier ) collected in two different ecosystems. We also investigated the relationship between shark size and the magnitude of differences in isotopic values between tis

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Hendry, K. R., G. E. A. Swann, M. J. Leng, et al. "Technical Note: Silica stable isotopes and silicification in a carnivorous sponge \\textit{Asbestopluma} sp." Biogeosciences Discussions 11, no. 12 (2014): 16573–97. http://dx.doi.org/10.5194/bgd-11-16573-2014.

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Abstract. The stable isotope composition of benthic sponge spicule silica is a potential source of palaeoceanographic information about past deep seawater chemistry. The silicon isotopic composition of spicules has been shown to relate to the silicic acid concentration of ambient water, although existing calibrations do exhibit a degree of scatter in the relationship. Less is known about how the oxygen isotope composition of sponge spicule silica relates to environmental conditions during growth. Here, we investigate the biological vital effects on silica silicon and oxygen isotope composition

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Meusburger, K., L. Mabit, J. H. Park, T. Sandor, and C. Alewell. "Combined use of stable isotopes and fallout radionuclides as soil erosion indicators in a forested mountain site, South Korea." Biogeosciences 10, no. 8 (2013): 5627–38. http://dx.doi.org/10.5194/bg-10-5627-2013.

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Abstract. The aim of this study is to assess and to validate the suitability of the stable nitrogen and carbon isotope signature as soil erosion indicators in a mountain forest site in South Korea. Our approach is based on the comparison of the isotope signature of "stable" landscape positions (reference sites), which are neither affected by erosion nor deposition, with eroding sites. For undisturbed soils we expect that the enrichment of δ15N and δ13C with soil depth, due to fractionation during decomposition, goes in parallel with a decrease in nitrogen and carbon content. Soil erosion proce

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Meusburger, K., L. Mabit, J. H. Park, T. Sandor, and C. Alewell. "Combined use of stable isotopes and fallout radionuclides as soil erosion indicators in a forested mountain site, South Korea." Biogeosciences Discussions 10, no. 2 (2013): 2565–89. http://dx.doi.org/10.5194/bgd-10-2565-2013.

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Abstract. The aim of this study is to assess and to validate the suitability of the stable nitrogen and carbon isotope signature as soil erosion indicators in a mountain forest site in South Korea. Our approach is based on the comparison of the isotope signature of "stable" landscape positions (reference sites), which are neither affected by erosion nor deposition, with eroding sites. For undisturbed soils we expect that the enrichment of δ15N and δ13C with soil depth, due to fractionation during decomposition, goes in parallel with a decrease in nitrogen and carbon content. Soil erosion proce

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Kurzweil, Florian, Corey Archer, Martin Wille, Ronny Schoenberg, Carsten Münker, and Olaf Dellwig. "Redox control on the tungsten isotope composition of seawater." Proceedings of the National Academy of Sciences 118, no. 18 (2021): e2023544118. http://dx.doi.org/10.1073/pnas.2023544118.

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Free oxygen represents an essential basis for the evolution of complex life forms on a habitable Earth. The isotope composition of redox-sensitive trace elements such as tungsten (W) can possibly trace the earliest rise of oceanic oxygen in Earth’s history. However, the impact of redox changes on the W isotope composition of seawater is still unknown. Here, we report highly variable W isotope compositions in the water column of a redox-stratified basin (δ186/184W between +0.347 and +0.810 ‰) that contrast with the homogenous W isotope composition of the open ocean (refined δ186/184W of +0.543

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Franco, Marcos A. L., Alejandra F. G. N. Santos, Abílio S. Gomes, Marcelo G. de Almeida, and Carlos E. de Rezende. "Use of stable isotopes in the evaluation of fish trophic guilds from a tropical hypersaline lagoon." Journal of the Marine Biological Association of the United Kingdom 100, no. 6 (2020): 979–88. http://dx.doi.org/10.1017/s0025315420000879.

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AbstractEnvironmental factors, size-related isotopic changes of the most abundant species and isotopic niche overlap were investigated using stable isotopes in order to evaluate spatial changes of fish trophic guilds in the Araruama Lagoon. Based on 440 muscle samples, 17 fish species were grouped into five trophic guilds. Mean salinity was above 40 at both sites sampled and a significant spatial difference was observed. The highest δ13C mean value was observed for an omnivorous species, whereas the lowest carbon signatures were found for the three fish species belonging to the planktivorous g

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Hendry, K. R., G. E. A. Swann, M. J. Leng, et al. "Technical Note: Silica stable isotopes and silicification in a carnivorous sponge <i>Asbestopluma</i> sp." Biogeosciences 12, no. 11 (2015): 3489–98. http://dx.doi.org/10.5194/bg-12-3489-2015.

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Abstract. The stable isotope composition of benthic sponge spicule silica is a potential source of palaeoceanographic information about past deep seawater chemistry. The silicon isotope composition of spicules has been shown to relate to the silicic acid concentration of ambient water, although existing calibrations do exhibit a degree of scatter in the relationship. Less is known about how the oxygen isotope composition of sponge spicule silica relates to environmental conditions during growth. Here, we investigate the vital effects on silica, silicon and oxygen isotope composition in a carni

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Tarboush, Rania A., Stephen E. MacAvoy, Stephen A. Macko, and Victoria Connaughton. "Contribution of catabolic tissue replacement to the turnover of stable isotopes in Danio rerio." Canadian Journal of Zoology 84, no. 10 (2006): 1453–60. http://dx.doi.org/10.1139/z06-136.

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Stable isotopes of carbon, nitrogen, and sulfur in organisms can trace nutrient sources and determine trophic interactions. However, time is required for an organism to reflect the isotopic composition of its diet. The rate at which an organism incorporates the isotopic signature of its food has a growth (k) component and a metabolic tissue replacement (m) component. This study shows that metabolic tissue replacement accounts for between 68% and 80% of the observed changes in isotopic signature in zebra danio ( Danio rerio (Hamilton, 1822)) muscle following a dietary shift, with the remainder

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Schöne, Bernd R., Aliona E. Meret, Sven M. Baier, et al. "Freshwater pearl mussels from northern Sweden serve as long-term, high-resolution stream water isotope recorders." Hydrology and Earth System Sciences 24, no. 2 (2020): 673–96. http://dx.doi.org/10.5194/hess-24-673-2020.

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Abstract. The stable isotope composition of lacustrine sediments is routinely used to infer Late Holocene changes in precipitation over Scandinavia and, ultimately, atmospheric circulation dynamics in the North Atlantic realm. However, such archives only provide a low temporal resolution (ca. 15 years), precluding the ability to identify changes on inter-annual and quasi-decadal timescales. Here, we present a new, high-resolution reconstruction using shells of freshwater pearl mussels, Margaritifera margaritifera, from three streams in northern Sweden. We present seasonally to annually resolve

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Karlson, Agnes M. L., Martin Reutgard, Andrius Garbaras, and Elena Gorokhova. "Isotopic niche reflects stress-induced variability in physiological status." Royal Society Open Science 5, no. 2 (2018): 171398. http://dx.doi.org/10.1098/rsos.171398.

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The isotopic niche has become an established concept in trophic ecology. However, the assumptions behind this approach have rarely been evaluated. Evidence is accumulating that physiological stress can affect both magnitude and inter-individual variability of the isotopic signature in consumers via alterations in metabolic pathways. We hypothesized that stress factors (inadequate nutrition, parasite infestations, and exposure to toxic substances or varying oxygen conditions) might lead to suboptimal physiological performance and altered stable isotope signatures. The latter can be misinterpret

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Timmerman, S., M. Honda, A. D. Burnham, et al. "Primordial and recycled helium isotope signatures in the mantle transition zone." Science 365, no. 6454 (2019): 692–94. http://dx.doi.org/10.1126/science.aax5293.

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Isotope compositions of basalts provide information about the chemical reservoirs in Earth’s interior and play a critical role in defining models of Earth’s structure. However, the helium isotope signature of the mantle below depths of a few hundred kilometers has been difficult to measure directly. This information is a vital baseline for understanding helium isotopes in erupted basalts. We measured He-Sr-Pb isotope ratios in superdeep diamond fluid inclusions from the transition zone (depth of 410 to 660 kilometers) unaffected by degassing and shallow crustal contamination. We found extreme

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Haramis, G. Michael, Dennis G. Jorde, Stephen A. Macko, Jane L. Walker, and W. H. Karasov. "Stable-Isotope Analysis of Canvasback Winter Diet in Upper Chesapeake Bay." Auk 118, no. 4 (2001): 1008–17. http://dx.doi.org/10.1093/auk/118.4.1008.

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Abstract A major decline in submerged aquatic vegetation (SAV) in Chesapeake Bay has altered the diet of wintering Canvasbacks (Aythya valisineria) from historically plant to a combination of benthic animal foods, especially the ubiquitous Baltic clam (Macoma balthica), supplemented with anthropogenic corn (Zea mays). Because the isotopic signature of corn is readily discriminated from bay benthos, but not SAV, we used stable-isotope methodology to investigate the corn–SAV component of the winter diet of Canvasbacks. Feeding trials with penned Canvasbacks were conducted to establish turnover r

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Kurisu, Minako, and Yoshio Takahashi. "Testing Iron Stable Isotope Ratios as a Signature of Biomass Burning." Atmosphere 10, no. 2 (2019): 76. http://dx.doi.org/10.3390/atmos10020076.

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Biomass burning is an important source of soluble Fe transported to the open ocean; however, its exact contribution remains unclear. Iron isotope ratios can be used as a tracer because Fe emitted by combustion can yield very low Fe isotope ratios due to isotope fractionation during evaporation processes. However, data on Fe isotope ratios of aerosol particles emitted during biomass burning are lacking. We collected size-fractionated aerosol samples before, during, and after a biomass burning event and compared their Fe isotope ratios. On the basis of the concentrations of several elements and

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Windhorst, D., T. Waltz, E. Timbe, H. G. Frede, and L. Breuer. "Impact of elevation and weather patterns on the isotopic composition of precipitation in a tropical montane rainforest." Hydrology and Earth System Sciences 17, no. 1 (2013): 409–19. http://dx.doi.org/10.5194/hess-17-409-2013.

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Abstract. This study presents the spatial and temporal variability of δ18O and δ2H isotope signatures in precipitation of a south Ecuadorian montane cloud forest catchment (San Francisco catchment). From 2 September to 25 December 2010, event sampling of open rainfall was conducted along an altitudinal transect (1800 to 2800 m a.s.l.) to investigate possible effects of altitude and weather conditions on the isotope signature. The spatial variability is mainly affected by the altitude effect. The event based δ18O altitude effect for the study area averages −0.22‰ × 100 m−1 (δ2H: −1.12‰ × 100 m−

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Windhorst, D., T. Waltz, H. G. Frede, and L. Breuer. "Impact of elevation and weather patterns on the isotopic composition of precipitation in a tropical montane rainforest." Hydrology and Earth System Sciences Discussions 9, no. 7 (2012): 8425–53. http://dx.doi.org/10.5194/hessd-9-8425-2012.

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Abstract. This study presents the spatial and temporal variability of δ18O and δ2H isotope signatures in precipitation of a south Ecuadorian montane cloud forest catchment (San Francisco Catchment). From 2 September to 25 December 2010, event sampling of open rainfall was conducted along an altitudinal transect (1800 m a.s.l. to 2800 m a.s.l.) to investigate possible effects of altitude and weather conditions on the isotope signature. The spatial variability is mainly affected by the altitude effect. The event based δ18O altitude effect for the study area averages −0.22‰ × 100 m−1 (δ2H: −1.12‰

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Geske, A., R. H. Goldstein, V. Mavromatis та ін. "The magnesium isotope (δ26Mg) signature of dolomites". Geochimica et Cosmochimica Acta 149 (січень 2015): 131–51. http://dx.doi.org/10.1016/j.gca.2014.11.003.

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Beck, Jonas, Michael Bock, Jochen Schmitt, Barbara Seth, Thomas Blunier, and Hubertus Fischer. "Bipolar carbon and hydrogen isotope constraints on the Holocene methane budget." Biogeosciences 15, no. 23 (2018): 7155–75. http://dx.doi.org/10.5194/bg-15-7155-2018.

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Abstract. Atmospheric methane concentration shows a well-known decrease over the first half of the Holocene following the Northern Hemisphere summer insolation before it started to increase again to preindustrial values. There is a debate about what caused this change in the methane concentration evolution, in particular, whether an early anthropogenic influence or natural emissions led to the reversal of the atmospheric CH4 concentration evolution. Here, we present new methane concentration and stable hydrogen and carbon isotope data measured on ice core samples from both Greenland and Antarc

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Mazariegos, Junior G., Jennifer C. Walker, Xiaomei Xu, and Claudia I. Czimczik. "Tracing Artificially Recharged Groundwater using Water and Carbon Isotopes." Radiocarbon 59, no. 2 (2016): 407–21. http://dx.doi.org/10.1017/rdc.2016.51.

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AbstractWe conducted an isotopic analysis of groundwater in Orange County, California, USA, around the Talbert Seawater Injection Barrier to determine if recycled water, used to artificially recharge local aquifers, carries a unique isotopic signature that can be used as a tracer. From September 2014 to April 2015, we collected groundwater from six privately owned wells within the coastal groundwater basin, along with various surface waters. All water samples were analyzed for their stable isotopic composition (δ18O, δD), the δ13C and 14C signature of the dissolved inorganic carbon (DIC) pool,

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DICKIN, ALAN P. "The Chondritic Moon: a solution to the 142Nd conundrum and implications for terrestrial mantle evolution." Geological Magazine 153, no. 3 (2016): 548–55. http://dx.doi.org/10.1017/s0016756815000990.

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AbstractRecent discoveries that the Earth has a supra-chondritic 142Nd signature have thrown chondritic geochemical Earth models into doubt. Several solutions have been proposed to explain this discrepancy but none has been widely accepted. This paper reviews Nd isotope data for the Moon which bridge the gap between the 142Nd signatures of chondritic meteorites and the accessible Earth. Different chondrite classes define a 142Nd–148Nd correlation line attributed to incomplete mixing of nucleosynthetic components in the solar nebula. Terrestrial standards have 142Nd signatures well above this c

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