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Stable Carbon and Nitrogen Isotopic
Aquatic Geochemistry, 2004The perennially ice-covered lakes in the McMurdo Dry Valleys, Antarctica, are part of the coldest and driest ecosystem on earth. To understand lacustrine carbon and nitrogen cycling in this end-member ecosystem, and to define paleolimnological proxies for ice-covered lakes, we measured the stable carbon and nitrogen isotopic composition of particulate ...
Jennifer Lawson +4 more
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Stable carbon isotopic composition of biogenic carbonates
Geochimica et Cosmochimica Acta, 1965Abstract The geology and sulfur isotopic composition of epigenetic pyrite of the Gas Hills district, Wyoming, indicate a bacterial origin for these sandstone-type uranium deposits. The δC13 value of epigenetic calcite associated with organic materials, however, is heavier than the isotopic composition of calcite of biogenic native sulfur deposits ...
E.S Cheney, M.L Jensen
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Journal of Forensic Sciences, 2008
Abstract: There remains significant uncertainty in illicit marijuana cultivation. We analyzed the δ13C and δ15N of 508 domestic samples from known U.S.A. counties, 31 seized from a single location, 5 samples grown in Mexico and Colombia, and 10 northwest border seizures. For a subset, inflorescences and leaves were analyzed separately.
Jason B, West +2 more
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Abstract: There remains significant uncertainty in illicit marijuana cultivation. We analyzed the δ13C and δ15N of 508 domestic samples from known U.S.A. counties, 31 seized from a single location, 5 samples grown in Mexico and Colombia, and 10 northwest border seizures. For a subset, inflorescences and leaves were analyzed separately.
Jason B, West +2 more
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Two New Carbonate Stable‐Isotope Standards
Geostandards Newsletter, 1982Two new carbonate isotope standards have been prepared for distribution by the IAEA and NBS. The first, TS limestone, NBS #19, will substitute for PDB, while the second carbonate, NBS #18 is depleted in 18O and 13C compared to the first.
Irving FRIEDMAN +2 more
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Stable carbon isotopes in marine porewaters
Earth and Planetary Science Letters, 1985Abstract We present centimeter-scale porewater δ 13 C profiles from four sites in the Central Equatorial Pacific Ocean, which reveal steep porewater δ 13 C gradients (up to −1.0‰ cm −1 ) at the deep-sea sediment—water interface. We describe the processes controlling porewater carbon isotopic composition and incorporate them into a model of the deep ...
Daniel C. McCorkle +2 more
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Quantifying pedogenic carbonate accumulations using stable carbon isotopes
Geoderma, 1998Abstract Four pedons from a late Quaternary chronosequence developed in calcareous alluvium in central Texas were investigated to assess the ability of the stable C isotope method to partition and quantify pedogenic carbonate accumulations. To quantify pedogenic carbonate accumulations with this method, δ 13 C values of bulk, pedogenic, and parent ...
L.C. Nordt +3 more
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Carbon stable isotopes as indicators of coastal eutrophication
Ecological Applications, 2014Coastal ecologists and managers have frequently used nitrogen stable isotopes (δ15N) to trace and monitor sources of anthropogenic nitrogen (N) in coastal ecosystems. However, the interpretation of δ15N data can often be challenging, as the isotope values fractionate substantially due to preferential retention and uptake by biota.
Autumn, Oczkowski +3 more
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Assessment of Carbon Allocation with Stable Carbon Isotope Labeling
Agronomy Journal, 1990AbstractLabeling plants with isotopic forms of C allows many processes important to agriculture and/or natural resource management to be studied. Most C‐labelling experiments have employed radioactive 14C, but in recent years regulatory constraints associated with use of radioactive materials appear to have curtailed studies which may have benefited ...
Tony J. Svejcar +2 more
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Stable Carbon Isotopic Evidence for Carbon Limitation in Hydrothermal Vent Vestimentiferans
Science, 1990Stable carbon isotope composition (δ 13 C values) can be used to evaluate an animal's source of nutritional carbon. Most animals with chemoautotrophic endosymbionts have quite negative tissue δ 13 C values due to discrimination against 13 C associated with ...
C R, Fisher, M C, Kennicutt, J M, Brooks
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The cycle of carbon and the stable carbon isotopes
Geochimica et Cosmochimica Acta, 1956The following estimates are used: carbonate carbon (A) 2420 ± 560 grammes, C12C13 = 88·55 ± 0·05; organic sedimentary carbon (B) between 0·1–0·5 per cent C in shales, C12C13 = 91·00 ± 0·1θ. The concept “crustal carbon” is defined, and based on the measurements of the isotope ratios of thirty-seven diamonds, nineteen carbonates from Ivigtut, some other ...
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