Relevant bibliographies by topics / Carbon isotope ratios

Academic literature on the topic 'Carbon isotope ratios'

Author: Grafiati
Published: 10 December 2022
Last updated: 30 January 2023

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Contents

Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Carbon isotope ratios.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Journal articles on the topic "Carbon isotope ratios"

1

Kelly, Jeffrey F. "Stable isotopes of carbon and nitrogen in the study of avian and mammalian trophic ecology." Canadian Journal of Zoology 78, no. 1 (February 28, 2000): 1–27. http://dx.doi.org/10.1139/z99-165.

Full text
Abstract:
Differential fractionation of stable isotopes of carbon during photosynthesis causes C4 plants and C3 plants to have distinct carbon-isotope signatures. In addition, marine C3 plants have stable-isotope ratios of carbon that are intermediate between C4 and terrestrial C3 plants. The direct incorporation of the carbon-isotope ratio (13C/12C) of plants into consumers' tissues makes this ratio useful in studies of animal ecology. The heavy isotope of nitrogen (15N) is preferentially incorporated into the tissues of the consumer from the diet, which results in a systematic enrichment in nitrogen-isotope ratio (15N/14N) with each trophic level. Consequently, stable isotopes of nitrogen have been used primarily to assess position in food chains. The literature pertaining to the use of stable isotopes of carbon and nitrogen in animal trophic ecology was reviewed. Data from 102 studies that reported stable-isotope ratios of carbon and (or) nitrogen of wild birds and (or) mammals were compiled and analyzed relative to diet, latitude, body size, and habitat moisture. These analyses supported the predicted relationships among trophic groups. Carbon-isotope ratios differed among species that relied on C3, C4, and marine food chains. Likewise, nitrogen-isotope ratios were enriched in terrestrial carnivorous mammals relative to terrestrial herbivorous mammals. Also, marine carnivores that ate vertebrates had nitrogen-isotope ratios that were enriched over the ratios of those that ate invertebrates. Data from the literature also indicated that (i) the carbon-isotope ratio of carnivore bone collagen was inversely related to latitude, which was likely the result of an inverse relationship between the proportion of carbon in the food chain that was fixed by C4 plants and latitude; (ii) seabirds and marine mammals from northern oceans had higher nitrogen-isotope ratios than those from southern oceans; (iii) the nitrogen-isotope ratios of terrestrial mammals that used xeric habitats were higher than the ratios of those that used mesic habitats, indicating that water stress can have important effects on the nitrogen-isotope ratio; (iv) there was no relationship between body mass and nitrogen-isotope ratio for either bone collagen or muscle of carnivores; and (v) there was linear covariation between stable-isotope ratios of carbon and nitrogen in marine food chains (but not in terrestrial C3 or C4 food chains), which is likely a product of increases in carbon-isotope ratio with trophic level in marine food chains. Differences in stable-isotope composition among trophic groups were detected despite variation attributable to geographic location, climate, and analytical techniques, indicating that these effects are large and pervasive. Consequently, as knowledge of the distribution of stable isotopes of carbon and nitrogen increases, they will probably become an increasingly important tool in the study of avian and mammalian trophic ecology.
APA, Harvard, Vancouver, ISO, and other styles
2

Watkinson, Charles J., Peter Gasson, Gareth O. Rees, and Markus Boner. "The Development and Use of Isoscapes to Determine the Geographical Origin of Quercus spp. in the United States." Forests 11, no. 8 (August 7, 2020): 862. http://dx.doi.org/10.3390/f11080862.

Full text
Abstract:
The stable isotope ratios of oxygen, hydrogen, carbon and sulfur from extracted wood of 87 samples of oaks from the United States were analysed. Relationships with climate variables and the stable isotope ratios of the 69 training dataset samples were investigated to a monthly resolution using long-term monthly mean climate data from NASA and the University of East Anglia’s Climate Research Unit, in conjunction with forecast data for hydrogen and oxygen isotope ratios in precipitation. These relationships were used to construct model isoscapes for oxygen, hydrogen, carbon and sulfur for US oak with the aim of using them to forecast isotopic patterns in areas that were not sampled and predict values in samples not used to construct the models. The leading predictors for isoscape generation were oxygen isotope ratios in January precipitation for oak oxygen isotope ratios, hydrogen isotope ratios in July precipitation for oak hydrogen isotope ratios, water vapour in April for carbon isotope ratios, and reflected shortwave radiation in March in combination with sulfate concentration in May for oak sulfur isotopes. The generated isoscapes can be used to show regions an unknown sample may have originated from with a resolution dependent on the rarity of the stable isotope signature within the United States. The models were assessed using the data of 18 samples of georeferenced oak. The assessment found that 100% of oxygen, 94% of hydrogen, 78% of carbon, and 94% of sulfur isotope ratios in the 18 test dataset samples fell within two standard deviations of the isoscape models. Using the results of the isoscapes in combination found that there were 4/18 test samples which did not fall within two standard deviations of the four models, this is largely attributed to the lower predictive power of the carbon isoscape model in conjunction with high local variability in carbon isotope ratios in both the test and training data. The method by which this geographic origin method has been developed will be useful to combat illegal logging and to validate legal supply chains for the purpose of good practice due diligence.
APA, Harvard, Vancouver, ISO, and other styles
3

Fricke, Henry C., Raymond R. Rogers, and Terry A. Gates. "Hadrosaurid migration: inferences based on stable isotope comparisons among Late Cretaceous dinosaur localities." Paleobiology 35, no. 2 (2009): 270–88. http://dx.doi.org/10.1666/08025.1.

Full text
Abstract:
Stable carbon and oxygen isotope ratios were measured for carbonate in samples of hadrosaurid tooth enamel and dentine, and gar scale ganoine and dentine from five geologically “contemporaneous“ (two-million-year resolution) and geographically distant late Campanian formations (Two Medicine, Dinosaur Park, Judith River, Kaiparowits, and Fruitland) in the Western Interior Basin. In all cases, isotopic offsets were observed between enamel and dentine from the same teeth, with dentine being characterized by higher and more variable carbon and oxygen isotope ratios. Isotopic offsets were also observed between gar ganoine and hadrosaur enamel in all sites analyzed. Both of these observations indicate that diagenetic overprinting of enamel isotope ratios did not entirely obfuscate primary signals. Decreases in carbon and oxygen isotope ratios were observed in hadrosaur enamel from east to west, and overlap in isotope ratios occurred only between two of the sampled sites (Dinosaur Park and Judith River Formations).The lack of isotopic overlap for enamel among localities could be due to diagenetic resetting of isotope ratios such that they reflect local groundwater effects rather than primary biogenic inputs. However, the large range in carbon isotope ratios, the consistent taxonomic offsets for enamel/ganoine data, and comparisons of enamel-dentine data from the same teeth all suggest that diagenesis is not the lone driver of the signal. In the absence of major alteration, the mostly likely explanation for the isotopic patterns observed is that hadrosaurids from the targeted formations were eating plants and drinking waters with distinct isotopic ratios. One implication of this reconstruction is that hadrosaurids in the Late Cretaceous of the Western Interior did not migrate to an extent that would obscure local isotopic signatures.
APA, Harvard, Vancouver, ISO, and other styles
4

Sare, David T. J., John S. Millar, and Frederick J. Longstaffe. "Tracing dietary protein in red-backed voles (Clethrionomys gapperi) using stable isotopes of nitrogen and carbon." Canadian Journal of Zoology 83, no. 5 (May 1, 2005): 717–25. http://dx.doi.org/10.1139/z05-064.

Full text
Abstract:
We examined the stable isotopes of nitrogen and carbon in a small mammal, the red-backed vole (Clethroinomys gapperi (Vigors, 1830)), to determine if isotope signatures reflect diet composition. Nitrogen- and carbon-isotope ratios in tissues from voles maintained on different protein levels in the laboratory were compared with wild-trapped voles. The isotopic fractionation of dietary nitrogen and carbon was also examined as food was digested in the stomach, incorporated into bone collagen, bioapatite, and hair, and excreted as feces. Nitrogen and carbon isotopes were fractionated differently depending on the isotopic composition and protein content of the diet. δ15N and δ13C values appear to be influenced by factors in addition to diet, such as macronutrients metabolized for respiration, metabolic rate, and periods of protein shortage.
APA, Harvard, Vancouver, ISO, and other styles
5

Holzkämper, Steffen, Päivi Kaislahti Tillman, Peter Kuhry, and Jan Esper. "Comparison of stable carbon and oxygen isotopes in Picea glauca tree rings and Sphagnum fuscum moss remains from subarctic Canada." Quaternary Research 78, no. 2 (June 20, 2012): 295–302. http://dx.doi.org/10.1016/j.yqres.2012.05.014.

Full text
Abstract:
AbstractStable isotope ratios from tree rings and peatland mosses have become important proxies of past climate variations. We here compare recent stable carbon and oxygen isotope ratios in cellulose of tree rings from white spruce (Picea glauca), growing near the arctic tree line; and cellulose of Sphagnum fuscum stems, growing in a hummock of a subarctic peatland, in west-central Canada. Results show that carbon isotopes in S. fuscum correlate significantly with July temperatures over the past ~20 yr. The oxygen isotopes correlate with both summer temperature and precipitation. Analyses of the tree-ring isotopes revealed summer temperatures to be the main controlling factor for carbon isotope variations, whereas tree-ring oxygen isotope ratios are controlled by a combination of spring temperatures and precipitation totals. We also explore the potential of combining high-frequency (annual) climate signals derived from long tree-ring series with low-frequency (decadal to centennial) climate signals derived from the moss remains in peat deposits. This cross-archive comparison revealed no association between the oxygen isotopes, which likely results from the varying sensitivity of the archives to different seasons. For the carbon isotopes, common variance could be achieved through adjustments of the Sphagnum age model within dating error.
APA, Harvard, Vancouver, ISO, and other styles
6

Price, T. Douglas, Vera Tiesler, William J. Folan, and Robert H. Tykot. "CALAKMUL AS A CENTRAL PLACE: ISOTOPIC INSIGHTS ON URBAN MAYA MOBILITY AND DIET DURING THE FIRST MILLENNIUM AD." Latin American Antiquity 29, no. 3 (July 24, 2018): 439–54. http://dx.doi.org/10.1017/laq.2018.31.

Full text
Abstract:
Isotopic investigations of human burials from excavations of the Autonomous University of Campeche (CIHS) at the prehispanic Maya capital of Calakmul in southeastern Mexico, near the border with Guatemala, include determination of radiocarbon dates; carbon and nitrogen isotope ratios in collagen; and strontium, carbon, and oxygen isotope ratios in tooth enamel. A total of 22 human and 5 faunal samples analyzed for strontium isotopes reveal a narrow range of variation in values, pointing to the likely local origin of over two-thirds of the central population of Calakmul, including two of its rulers. Carbon and nitrogen data confirm a typical Classic Maya diet at the site and identify a diet high in meat consumption for one dynastic individual. Interpreted jointly, the isotopic information offers new perspectives on the provenience and lifestyles of the residents of Calakmul, including a potential place of origin for the royal occupant of chamber tomb Burial VII-1.
APA, Harvard, Vancouver, ISO, and other styles
7

Krueger, Dana A., Rae-Gabrielle Krueger, and Harold W. Krueger. "Carbon Isotope Ratios of Various Fruits." Journal of AOAC INTERNATIONAL 69, no. 6 (November 1, 1986): 1035–36. http://dx.doi.org/10.1093/jaoac/69.6.1035.

Full text
Abstract:
Abstract Carbon stable isotope ratio analysis (SIRA) has been applied to detect adulteration of apple, orange, honey, and other products with cane or corn sugars. We analyzed numerous other fruits to determine the applicability of carbon SIRA to detecting adulteration in these fruits as well. The results indicate that the use of carbon SIRA may be generalized to most fruits of commercial importance.
APA, Harvard, Vancouver, ISO, and other styles
8

McInerney, Francesca A., Caroline A. E. Strömberg, and James W. C. White. "The Neogene transition from C3 to C4 grasslands in North America: stable carbon isotope ratios of fossil phytoliths." Paleobiology 37, no. 1 (2011): 23–49. http://dx.doi.org/10.1666/09068.1.

Full text
Abstract:
C4 grasses form the foundation of warm-climate grasslands and savannas and provide important food crops such as corn, but their Neogene rise to dominance is still not fully understood. Carbon isotope ratios of tooth enamel, soil carbonate, carbonate cements, and plant lipids indicate a late Miocene-Pliocene (8–2 Ma) transition from C3 vegetation to dominantly C4 grasses at many sites around the world. However, these isotopic proxies cannot identify whether the C4 grasses replaced woody vegetation (trees and shrubs) or C3 grasses. Here we propose a method for reconstructing the carbon isotope ratio of Neogene grasses using the carbon isotope ratio of organic matter trapped in plant silica bodies (phytoliths). Although a wide range of plants produce phytoliths, we hypothesize that in grass-dominated ecosystems the majority of phytoliths will be derived from grasses, and will yield a grass carbon isotope signature. Phytolith extracts can be contaminated by non-phytolith silica (e.g., volcanic ash). To test the feasibility of the method given these potential problems, we examined sample purity (phytolith versus non-phytolith silica), abundance of grass versus non-grass phytoliths, and carbon isotope ratios of phytolith extracts from late Miocene-Pliocene paleosols of the central Great Plains. Isotope results from the purest samples are compared with phytolith assemblage analysis of these same extracts. The dual record spans the interval of focus (ca. 12–2 Ma), allowing us, for the first time, to investigate how isotopic shifts correlate with floral change.We found that many samples contained high abundances of non-biogenic silica; therefore, only a small subset of “pure” samples (>50% of phytoliths by volume) with good preservation were considered to provide reliable carbon isotope ratios. All phytolith assemblages contained high proportions (on average 85%) of grass phytoliths, supporting our hypothesis for grass-dominated communities. Therefore, the carbon isotope ratio of pure, well-preserved samples that are dominated by grass biosilica is considered a reliable measure of the proportion of C3 and C4 grasses in the Neogene.The carbon isotope ratios of the pure fossil phytolith samples indicate a transition from predominantly C3 grasses to mixed C3-C4 grasses by 5.5 Ma and then a shift to more than 80% C4 grasses by 3–2 Ma. With the exception of the Pliocene sample, these isotopic data are broadly concordant with phytolith assemblages that show a general increase in C4 grasses in the late Miocene. However, phytolith assemblage analysis indicates lower relative abundance of C4 grasses in overall vegetation than do the carbon isotopes from the same phytolith assemblages. The discrepancy may relate to either (1) incomplete identification of (C4) PACMAD phytoliths, (2) higher production of non-diagnostic phytoliths in C4 grasses compared to C3 grasses, or (3) biases in the isotope record toward grasses rather than overall vegetation. The impact of potential incomplete characterization of (C4) PACMAD phytoliths on assemblage estimates of proportion of C4, though important, cannot reconcile discrepancies between the methods. We explore hypothesis (2) by analyzing a previously published data set of silica content in grasses and a small data set of modern grass leaf assemblage composition using analysis of variance, independent contrasts, and sign tests. These tests suggest that C4 grasses do not have more silica than C3 grasses; there is also no difference with regard to production of non-diagnostic phytoliths. Thus, it is most likely that the discrepancy between phytolith assemblages and isotope ratios is a consequence of hypothesis (3), that the isotope signature is influenced by the contribution of non-diagnostic grass phytoliths, whereas the assemblage composition is not. Assemblage-based estimates of % C4 within grasses, rather than overall vegetation, are in considerably better agreement with the isotope-based estimates. These results support the idea that, in grass-dominated assemblages, the phytolith carbon isotope method predominantly records shifts in dominant photosynthetic pathways among grasses, whereas phytolith assemblage analysis detects changes in overall vegetation. Carbon isotope ratios of fossil phytoliths in conjunction with phytolith assemblage analysis suggest that the late Neogene expansion of C4 grasses was largely at the expense of C3 grasses rather than C3 shrubs/trees. Stable isotopic analysis of phytoliths can therefore provide unique information about grass community changes during the Neogene, as well as help test how grass phytolith morphology relates to photosynthetic pathway.
APA, Harvard, Vancouver, ISO, and other styles
9

Irei, Satoshi. "Isotopic Characterization of Gaseous Mercury and Particulate Water-Soluble Organic Carbon Emitted from Open Grass Field Burning in Aso, Japan." Applied Sciences 12, no. 1 (December 23, 2021): 109. http://dx.doi.org/10.3390/app12010109.

Full text
Abstract:
Biomass burning is one of the major emitters of airborne particulate matter (PM) and gaseous mercury. In order to apply the isotopic fingerprinting method to process identification and source apportionment studies, isotopic characterizations of targeted substances at emission are indispensable. Here, we report the stable isotopic composition of total gaseous mercury (TGM) and the stable and radiocarbon isotopic composition of low-volatile water-soluble nitrogen (LV-WSN) and organic carbon (LV-WSOC) in PM emitted from open grass field burning in the Aso region of Japan. The measurement results showed that TGM concentrations in the air increased during the open field burning events, indicating the presence of TGM emissions. The results of LV-WSN analysis showed very low concentrations; therefore, the stable nitrogen isotope ratios could not be measured. The stable mercury isotope ratios exhibited lighter composition than those observed during non-biomass-burning days. The analysis of LV-WSOC revealed heavy stable carbon isotope ratios (average ± SD, −18 ± 2‰), suggesting a substantial contribution from C4 plant carbon. The 14C analysis showed that more than 98% of the LV-WSOC was modern carbon, indicating the contribution of plant carbon to PM emitted from biomass burning. The findings here provide reference isotope compositions of TGM and particulate LV-WSOC from biomass burning in this region.
APA, Harvard, Vancouver, ISO, and other styles
10

Watson, Elizabeth Burke, Alejandro Hinojosa-Corona, Johannes R. Krause, Juan Carlos Herguera, Julianna McDonnell, Karen Raquel Villegas Villegas Manríquez, Michelle E. Gannon, and Andrew B. Gray. "Lagoon Biogeochemical Processing is Reflected in Spatial Patterns of Sediment Stable Isotopic Ratios." Journal of Marine Science and Engineering 8, no. 11 (November 3, 2020): 874. http://dx.doi.org/10.3390/jmse8110874.

Full text
Abstract:
The spatial analysis of biota, particulate organic matter, and sediments for stable isotopes of carbon (δ13C), nitrogen (δ15N), and sulfur (δ34S) have proved useful for identifying patterns in productivity, nutrient pollution, and relationships between biological and physiochemical variables at the local and global scales. Yet such approaches are rarely applied to studies of lagoon or estuarine metabolism. Focusing on Bahía San Quintín, a heterotrophic seagrass-dominated lagoon on the Pacific coast of Baja California, México, we report on spatial patterns in surficial sediment CNS stable isotopic ratios as tracers of lagoon biogeochemical function. Stable nitrogen isotopes highlighted potential spatial variability in the balance between denitrification and nitrogen-fixation within the lagoon and identified an association between elevated δ15N levels and oyster culture, suggesting that oyster presence may be enhancing N2 production. Spatial patterns in δ34S covaried with sediment particle size, underlining the importance of sediment texture in determining the depth of sub-oxic-anoxic redox zones. Sediment carbon stable isotope ratios highlighted the lack of incorporation of seagrass carbon into seagrass meadow sediments, thus emphasizing the importance of phytoplankton or microphytobenthos for carbon accumulation in seagrass meadows. This report highlights the value of sediment isotopic values in corroborating spatial patterns in estuarine metabolism or macronutrient processing identified from chamber or flux-based studies. Stable isotope mapping can provide a useful addition to assessment of estuarine metabolism, or act as a stand-alone tool for generating hypotheses, identifying the influence of spatial gradients, and/or suggesting prime locations for investigation of microbial abundance or function.
APA, Harvard, Vancouver, ISO, and other styles
More sources

Dissertations / Theses on the topic "Carbon isotope ratios"

1

Lockheart, Matthew James. "Isotope compositions and distributions of individual compounds as indicators for environmental conditions : comparisons between contemporary and Clarkia fossil leaves." Thesis, University of Bristol, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389098.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Vaiglova, Petra. "Neolithic agricultural management in the Eastern Mediterranean : new insight from a multi-isotope approach." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:c8824136-da35-43b2-a700-f458d0cc2fdf.

Full text
Abstract:
The work presented in this dissertation explores the nature of agro-pastoral strategies developed by Neolithic farmers as a way to understand how early food production was inter-twined with environmental and socio-economic opportunities and constraints. Towards this end, a multi-isotope approach is used to address questions of scale and intensity of crop cultivation and animal management at the archaeological sites of Kouphovouno, southern Greece, Makriyalos, northern Greece, and Çatalhöyük, south-central Turkey. Measurements of stable carbon, nitrogen, oxygen and strontium isotope values of carbonized plant remains, human and animal bone collagen and animal tooth enamel are used to examine the similarities and differences in the types of treatments that individual species of plants and animals received during the agricultural cycle at the distinct locations. The results show that farmers at the three sites developed variable methods for exploiting the arable and pastoral landscape and catering to their economic and culinary needs. The discussion considers the implications of these findings to our understanding of the complexity and adaptability of early farming systems.
APA, Harvard, Vancouver, ISO, and other styles
3

Huset, Regina Anne. "Methyl halides : concentrations, fluxes and stable carbon isotope ratios measured in the atmosphere, coastal waters, and soils /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/11576.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Hörner, Gerald, Steffen Lau, and Hans-Gerd Löhmannsröben. "NIR-diode laser spectroscopy for isotope-selective sensing of soil-respired carbon dioxide." Universität Potsdam, 2004. http://opus.kobv.de/ubp/volltexte/2006/1014/.

Full text
Abstract:
The performance of a home-built tunable diode laser (TDL) spectrometer has been optimized regarding multi-line detection of carbon dioxide in natural gases. In the regime of the (3001)III ← (000) band of 12CO2 around 1.6 μm, the dominating isotope species 12CO2, 13CO2, and 12C18O16O were detected simultaneously. In contrast to most established techniques, selective measurements are performed without any sample preparation. This is possible since the CO2 detection is free of interference from water, ubiquitous in natural gases. Detection limits in the range of a few ppmv were obtained for each species utilizing wavelength modulation (WM) spectroscopy with balanced detection in a long-path absorption cell set-up. Linear calibration plots cover a dynamic range of four orders of magnitude, allowing for quantitative CO2 detection in various samples, like soil and breath gas. High isotopic resolution enables the excellent selectivity, sensitivity, and stability of the chosen analytical concept. The obtained isotopic resolution of typically ± 1.0 ‰ and ± 1.5 ‰ (for 3 vol. % and 0.7 vol. % of CO2, respectively) offers a promising analytical tool for isotope-ratio determination of carbon dioxide in soil gas. Preliminary experiments on soil respiration for the first time combine the on-line quantification of the overall carbon dioxide content with an optode sensor and isotopic determination (TDL system) of natural gas species.
APA, Harvard, Vancouver, ISO, and other styles
5

An, Yan. "The Potential of Bulk and Amino-Acid Specific Isotope Ratio Mass Spectrometry of Human Hair in Forensic and Clinical Applications." Ohio University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1363701887.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Trudell, Steven A. "Patterns of nitrogen and carbon stable isotope ratios in macrofungi, plants, and soils from two old-growth conifer forests, Olympic National Park, Washington, USA /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/5572.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Blaszczyck, D., Julia Beaumont, A. Krzyszowski, D. Poliński, and A. Drozd-Lipińska. "Social status and diet. Reconstruction of diet of individuals buried in some early medieval chamber graves from Poland by carbon and nitrogen stable isotopes analysis." Science Direct, 2021. http://hdl.handle.net/10454/18572.

Full text
Abstract:
Yes
The study presents results of the investigations of diet based on carbon and nitrogen stable isotope ratios (δ13C and δ15N) of the bone collagen of individuals buried in medieval elite chamber graves from the territory of the state of the first Piasts, Poland (the second half of the 10th and the first half of the 11th century). The aim of the research was to determine the diet of individuals buried in such funerary structures, to compare this with commoners buried in ordinary graves, and investigate any sex-related patterns. Rib bone samples were taken from individuals buried in chamber graves at Bodzia, Dziekanowice, Pień and Sowinki. Results indicate that the elite male diet was based on C3 plants with possible contribution of some C4 plants (millet) and substantial consumption of animal proteins including fish. The bone collagen δ13C and δ15N of male chamber burials suggested consumption of higher trophic level foodstuffs (meat and fish) whilst the female diet, and that of the juveniles, was similar to the commoners in the rest of the population.
APA, Harvard, Vancouver, ISO, and other styles
8

Gagen, M. H. "The response of pine trees to climate in the southern French Alps and the palaeoclimatic potential of stable carbon isotope ratios from treerings." Thesis, Swansea University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637018.

Full text
Abstract:
This thesis is grounded in Quaternary and global change science and considers the application of proxy analogues to reconstruct past climate. Latewood width, wood density and latewood holo cellulose δ13C series were compiled from treeline pine trees from the southern French Alps, with the aim of comparing and contrasting the types of climate information preserved in the three proxies and assessing the potential of δ13C for palaeoclimate reconstruction. Two main research questions were identified. First, what climate parameters might be reconstructed from the annual δ13C series? Second, how useful is the δ13C calibration for reconstructing palaeoclimate compared to ringwidth and density series? The calibration stage formed the bulk of the analysis. It was revealed that δ13C ratios are strongly controlled by growth season moisture stress, in a relationship that appears to have a high degree of temporal stability. The potential exists, therefore, for extracting a strong moisture-stress signal form long δ13C series from this region. It is argued that, lower frequency signal strength is often dramatically reduced or lost when short ringwidth and density series are standardised to remove growth trends. This thesis presents evidence to suggest that sub- to decadal frequency climate signals can be retained in δ13C series. It is concluded that there is great potential for reconstructing palaeoclimate with δ13C treering series. δ13C ratios are fixed by a simple biological process that is well understood, and are not greatly affected by site and stand characteristics, making the series far less 'noisy' than equivalent growth proxy data.
APA, Harvard, Vancouver, ISO, and other styles
9

Johnson, Laurie. "Assessing the effect of feather wear on carbon and nitrogen stable isotope ratios, and the use of stable isotopes to determine predator diets in the Namibian Islands marine protected area." Master's thesis, Faculty of Science, 2019. http://hdl.handle.net/11427/31248.

Full text
Abstract:
The stable isotope (SI) approach is widely used in ecological research to tackle problems such as delineating food web structure or tracing the migratory origins of various organisms. This thesis first tested the widely accepted assumption that SI ratios are fixed in an inert tissue, and then used the SI approach to infer the food web structure, from a marine top predator point of view, of a profoundly impacted marine ecosystem off southern Namibia. In bird research, it is assumed that SI ratios are fixed in feathers once they have completed their growth during moult. This assumption is crucial in determining where birds moult, and has been used to infer changes in the environment over time, as well as changes in the trophic levels of individuals. Recent comparisons of feathers collected from several penguin species during their annual moult have shown systematic differences between newly moulted and old feather SI ratios. I thus tested whether a change in SI ratios occurs as feathers age by comparing the carbon and nitrogen SI ratios of black and white feathers collected from captive, individually known African (Spheniscus demersus) and northern rockhopper (Eudyptes moseleyi) penguins at three occasions over a year. I found a clear trend for the rockhopper penguin feathers with new and old black feathers differing in their δ13C and δ15N values; this trend was not as clear for the African penguins. I then tested factors related to feather wear as a possible mechanism for differences in SI ratios between new and old feathers; these factors were feather reflectance and microstructure. In both penguin species, old black feathers reflected more light, and had a larger proportion of their barbs without barbules near their tips compared to new feathers. Feather wear may result in melanin leakage, which may explain the observed trends in the SI ratios between new and old pigmented penguin feathers. Differences in SI values were observed between species and may be a result of facility at which the penguins were housed, where one facility was exposed to more sunlight than the other, rather than the differences being a result of species. Although the differences observed were subtle, the state of feather wear (i.e. timing of feather collection within the moult cycle) should be considered in order to make accurate ecological inferences based on their SI ratios. Further research is needed to fully understand the phenomenon and to test whether the same process affects pigmented feathers of flying birds. I then used SI ratios to update our knowledge of resource partitioning among a marine top predator community in southern Africa, and to infer the marine food web structure in a Marine Protected Area off the southern Namibian coast. The Namibian Islands Marine Protected Area supports the most important breeding population of bank cormorants (Phalacrocorax neglectus; Endangered), and historically was important for two other Endangered seabirds: African penguins and Cape gannets (Morus capensis). Non-threatened marine top predators studied in the system were: greater crested terns (Thalasseus bergii) and Cape fur seals (Arctocephalus pusillus). In the last 50 years, shelf waters off southern Namibia have been overfished, resulting in an altered marine ecosystem; shoaling fish have been replaced by less nutrient-rich species such as hake (Merluccius spp.), jellyfish, and salps. Previous studies of the region’s food webs were based on traditional dietary analyses such as stomach content and scat analysis which provide short-term diet information. Here, I measured carbon and nitrogen SI ratios in several tissues of the marine top predators, and those of their potential prey species, to infer the marine food web for this region, and to complement short-term data obtained from traditional dietary analyses. Among the predator guild, Cape gannets had the lowest δ13C and δ15N values, indicating that they fed the farthest offshore and at the lowest trophic level both during the breeding season (from whole blood) and moulting period (from feathers). As expected, bank cormorant δ13C values indicated that they fed more benthically than the other predators, and Cape fur seals fed at the highest trophic level. African penguin tissue SI ratios were intermediate between those of Cape gannets and Cape fur seals. Greater crested terns exhibited the highest δ13C values, suggesting that they fed closest to shore. Bayesian mixing models used with species-specific discrimination factors (when available) revealed some resource partitioning among the marine top predators in this region but many made use of similar resources; sardine (Sardinops sagax), squid (Loligo reynaudii), and rock lobster (Jasus lalandii). This work highlights the most likely prey items used by marine top predators outside of the breeding period, and provides new insights into the food web of this region. Prior to the start of industrial fishing, marine top predators in this region mainly ate sardine and anchovy. Despite the collapse of these species’ populations in the 1970s, marine top predators currently still make use of these prey resources, which concurs with the results found from stomach content and scat analyses. In this thesis, I have shown experimentally that SI ratios vary slightly as feathers age in penguins. I have also used the SI technique in an ecological context to add to the knowledge on the diet of marine top predators of an overfished ecosystem. Overall I have shown how the SI approach can add to our understanding of trophic ecology, and also how the method is dependent on accurate SI inputs in order to make accurate dietary inferences.
APA, Harvard, Vancouver, ISO, and other styles
10

Xia, Yang. "Impact of varying NH₄⁺˸NO₃⁻ ratios in nutrient solution on C-isotope composition of leaf- and root-respired CO₂ and putative respiratory substrates in C₃ plants." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS222.

Full text
Abstract:
La composition isotopique (¹³C/¹²C) du CO₂ respiré par les feuilles et les racines dans l'obscurité et celle des substrats respiratoires putatifs, y compris les sucres solubles et les acides organiques (malate et citrate), l'activité de la PEPc ainsi que les échanges gazeux des feuilles ont été déterminés sur le haricot (Phaseolus vulgaris L.) et l’épinards (Spinacia oleracea L.) cultivés dans du sable avec différents rapports NH₄⁺: NO₃⁻ dans N fourni. Le CO₂ respiré par les feuilles était enrichi en ¹³C sous NO₃⁻ s’appauvrissant progressivement avec l’augmentation de la fraction de NH₄⁺ dans le N fourni, tandis que la composition isotopique du CO₂ issu de la respiration des racines restait inchangée quel que soit le rapport NH₄⁺: NO₃⁻. Nous avons suggéré qu'une plus grande quantité de pools enrichis en ¹³C fixés par la PEPc via la voie anaplérotique contribuait à la respiration foliaire sous NO₃⁻. Cependant, un effet similaire dans les racines attendu sous NH₄⁺ a été masqué en raison d'une refixation (par la PEPc) du CO₂ respiré (appauvrie en ¹³C). De manière inattendue, les modifications de la composition isotopique du C des métabolites individuels, leurs quantités, ainsi que l'activité de l’enzyme PEPc, présentaient des profils différents entre les deux espèces étudiées. Des expériences de double marquage (¹³C et ¹⁵N) sont nécessaires pour mieux comprendre l’impact de la plasticité métabolique du TCA sur l’écart isotopique entre le malate et le citrate et sur la composition isotopique du CO₂ respiré chez différentes espèces sous différentes formes d’azote
C-isotope composition of leaf- and root-respired CO₂ in the dark and that of putative respiratory substrates including soluble sugars and organic acids (malate and citrate), PEPc activity, as well as leaf gas exchanges were determined on bean (Phaseolus vulgaris L.) and spinach (Spinacia oleracea L.) plants grown in sand with varying ratios of NH₄⁺: NO₃⁻ in supplied N. Leaf-respired CO₂ was ¹³C enriched under NO₃⁻ nutrition and became progressively ¹³C depleted with increasing amount of NH₄⁺ in supplied N, while C-isotope composition of root-respired CO₂ remained unchanged across N-type gradient. We suggested that a higher amount of ¹³C enriched C-pools fixed by PEPc through anaplerotic pathway contributed to respired CO₂ in leaves under NO₃⁻ nutrition. However, a similar effect in roots expected under NH4+ nutrition was masked because of a rather ¹³C depleted C source (respired CO₂) refixation by PEPc. Unexpectedly, the changes in C-isotope composition of individual metabolites and their amounts as well as PEPc activity exhibited different patterns between the two species. Double labelling experiments (¹³C and ¹⁵N) are needed for better understanding the impact of metabolic plasticity of TCA on isotopic gap between malate and citrate and on C-isotope composition of respired CO₂ in different species under varying N-type nutrition
APA, Harvard, Vancouver, ISO, and other styles
More sources

Books on the topic "Carbon isotope ratios"

1

Jędrysek, Mariusz Orion. Spatial and temporal variations in carbon isotope ratio of early-diagenetic methane from freshwater sediments: Methanogenic pathways. Wrocław: Wydawn. Uniwersytetu Wrocławskiego, 1997.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
2

Ellam, Rob. Isotopes. Oxford University Press, 2016. http://dx.doi.org/10.1093/actrade/9780198723622.001.0001.

Full text
Abstract:
An isotope is a variant form of a chemical element, containing a different number of neutrons in its nucleus. Most elements exist as several isotopes. Many are stable, others are radioactive, and some may only exist fleetingly before decaying into other elements. The study of isotope ratios has become central to many areas of science, and used to probe the age and history of the Earth and the origins of the Solar System. Radioactive isotopes find wide applications, from nuclear power to medicine and carbon dating. Isotopes: A Very Short Introduction provides an overview of the nature of stable and radioactive isotopes, considering their wide range of modern applications.
APA, Harvard, Vancouver, ISO, and other styles
3

Geological Survey (U.S.), ed. Sulfur/carbon ratios and sulfur isotope composition of some Cretaceous shales from the western interior of North America. [Reston, Va.?]: Dept. of the Interior, U.S. Geological Survey, 1985.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
4

Ellam, Rob. 2. Isotopic clocks. Oxford University Press, 2016. http://dx.doi.org/10.1093/actrade/9780198723622.003.0002.

Full text
Abstract:
About one in a trillion atoms of carbon is the radioactive isotope 14C. It is a ‘cosmogenic isotope’ produced by the interaction between atmospheric nitrogen (N) and cosmic rays. The half-life of 14C is 5,730 years, so every 5,730 years the ratio of 14C to 12C will halve. ‘Isotopic clocks: the persistence of carbon’ describes how scientists Willard Libby, Hessel de Vries, Hans Seuss, and their contemporaries established the radiocarbon dating technique. Radiocarbon has become one of the most valuable isotopic tools available to scientists looking to date materials formed over the past 50,000 years or to trace and apportion different sources of carbon.
APA, Harvard, Vancouver, ISO, and other styles
5

National Aeronautics and Space Administration (NASA) Staff. Boreas Te-5 Tree Ring and Carbon Isotope Ratio Data. Independently Published, 2018.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
6

Canfield, Donald Eugene. Earth’s Middle Ages: What Came after the GOE. Princeton University Press, 2017. http://dx.doi.org/10.23943/princeton/9780691145020.003.0009.

Full text
Abstract:
This chapter considers the aftermath of the great oxidation event (GOE). It suggests that there was a substantial rise in oxygen defining the GOE, which may, in turn have led to the Lomagundi isotope excursion, which was associated with high rates of organic matter burial and perhaps even higher concentrations of oxygen. This excursion was soon followed by a crash in oxygen to very low levels and a return to banded iron formation deposition. When the massive amounts of organic carbon buried during the excursion were brought into the weathering environment, they would have represented a huge oxygen sink, drawing down levels of atmospheric oxygen. There appeared to be a veritable seesaw in oxygen concentrations, apparently triggered initially by the GOE. The GOE did not produce enough oxygen to oxygenate the oceans. Dissolved iron was removed from the oceans not by reaction with oxygen but rather by reaction with sulfide. Thus, the deep oceans remained anoxic and became rich in sulfide, instead of becoming well oxygenated.
APA, Harvard, Vancouver, ISO, and other styles

Book chapters on the topic "Carbon isotope ratios"

1

Langer, William D. "Galactic Carbon Monoxide Isotope Ratios." In CO: Twenty-Five Years of Millimeter-Wave Spectroscopy, 98–100. Dordrecht: Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-011-5414-7_18.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Ripperdan, Robert L. "13. Stratigraphic Variation in Marine Carbonate Carbon Isotope Ratios." In Stable Isotope Geochemistry, edited by John W. Valley and David R. Cole, 637–62. Berlin, Boston: De Gruyter, 2001. http://dx.doi.org/10.1515/9781501508745-016.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Kagawa, Akira, and Giovanna Battipaglia. "Post-photosynthetic Carbon, Oxygen and Hydrogen Isotope Signal Transfer to Tree Rings—How Timing of Cell Formations and Turnover of Stored Carbohydrates Affect Intra-annual Isotope Variations." In Stable Isotopes in Tree Rings, 429–62. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-92698-4_15.

Full text
Abstract:
AbstractIn this chapter, we discuss post-photosynthetic processes that affect intra-annual variation in the stable isotopes of tree rings, such as timing of cell formations and turnover of stored carbohydrates, by combining research findings gained by using either natural-abundance or artificially-enriched carbon, oxygenand hydrogen isotopes. We focus on within-ring variation in stable isotope ratios, with an emphasis on aligning observed ratios in whole wood or extracted cellulose to seasonal dynamics in climate and phenology. We also present a discussion of isotopic fractionation that operates within the scope of observed variations across individual rings. We then introduce a model that traces the seasonal partitioning of photosynthate into tree rings via storage pool, which is based on experimental data gained from labeling studies using artificially enriched 13CO2 gas. Finally, we will describe our current understanding of post-photosynthetic signal transfer processes of oxygenand hydrogen isotopes from leaves to tree rings, such as exchange of oxygen and hydrogen between storage carbohydrates and local cambial water, and possible causes of difference in oxygen and hydrogen isotope fractionations. Finally, we discuss mechanisms behind how oxygen and hydrogen from foliar-absorbed liquid water is then incorporated into wood biomass, by introducing results gained from recent H218O and HDO pulse-labeling experiments.
APA, Harvard, Vancouver, ISO, and other styles
4

Kagawa, Akira, and Giovanna Battipaglia. "Post-photosynthetic Carbon, Oxygen and Hydrogen Isotope Signal Transfer to Tree Rings—How Timing of Cell Formations and Turnover of Stored Carbohydrates Affect Intra-annual Isotope Variations." In Stable Isotopes in Tree Rings, 429–62. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-92698-4_15.

Full text
Abstract:
AbstractIn this chapter, we discuss post-photosynthetic processes that affect intra-annual variation in the stable isotopes of tree rings, such as timing of cell formations and turnover of stored carbohydrates, by combining research findings gained by using either natural-abundance or artificially-enriched carbon, oxygenand hydrogen isotopes. We focus on within-ring variation in stable isotope ratios, with an emphasis on aligning observed ratios in whole wood or extracted cellulose to seasonal dynamics in climate and phenology. We also present a discussion of isotopic fractionation that operates within the scope of observed variations across individual rings. We then introduce a model that traces the seasonal partitioning of photosynthate into tree rings via storage pool, which is based on experimental data gained from labeling studies using artificially enriched 13CO2 gas. Finally, we will describe our current understanding of post-photosynthetic signal transfer processes of oxygenand hydrogen isotopes from leaves to tree rings, such as exchange of oxygen and hydrogen between storage carbohydrates and local cambial water, and possible causes of difference in oxygen and hydrogen isotope fractionations. Finally, we discuss mechanisms behind how oxygen and hydrogen from foliar-absorbed liquid water is then incorporated into wood biomass, by introducing results gained from recent H218O and HDO pulse-labeling experiments.
APA, Harvard, Vancouver, ISO, and other styles
5

Gessler, Arthur, and Juan Pedro Ferrio. "Postphotosynthetic Fractionation in Leaves, Phloem and Stem." In Stable Isotopes in Tree Rings, 381–96. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-92698-4_13.

Full text
Abstract:
AbstractStable carbon isotope ratios (δ13C) in organic matter convey important integrated and (if assessed in the tree ring archive) dateable information on plant physiology and related environmental drivers. While the generation of the δ13C signal in the primary assimilates in the leaves via photosynthetic carbon isotope fractionation is well understood, we still lack detailed knowledge of the processes that determine the isotopic fractionation in downstream processes in the leaves and during the transport in the stem, which in turn affect δ13C in the tree-ring archive. We here provide an update on processes that drive post-carboxylationcarbon isotope fractionation in the leaves, on potential changes in δ13C related to phloem loading and transport and we also discuss the role of stem CO2 fluxes (bark photosynthesis, stem respiration and CO2 fixation by phosphoenol pyruvate carboxylase). Moreover, we address the impact of carbon storage and remobilization on the intra-annual variation of δ13C in tree rings. Finally, we point to the potential importance of the intra-molecularcarbon isotope distribution in carbohydrates for tree ring δ13C and its relation to shifts in metabolic pathways.
APA, Harvard, Vancouver, ISO, and other styles
6

Ehleringer, J. R. "Carbon Isotope Ratios and Physiological Processes in Aridland Plants." In Stable Isotopes in Ecological Research, 41–54. New York, NY: Springer New York, 1989. http://dx.doi.org/10.1007/978-1-4612-3498-2_3.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Still, Christopher J., and Rebecca L. Powell. "Continental-Scale Distributions of Vegetation Stable Carbon Isotope Ratios." In Isoscapes, 179–93. Dordrecht: Springer Netherlands, 2009. http://dx.doi.org/10.1007/978-90-481-3354-3_9.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Schimmelmann, Arndt. "Carbon, Nitrogen and Oxygen Stable Isotope Ratios in Chitin." In Topics in Geobiology, 81–103. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-90-481-9684-5_4.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Hinkle, Kenneth H., and Werner W. G. Scharlach. "Carbon Isotope Ratios in Oxygen Rich Mira and SRa Variables." In Cool Stars with Excesses of Heavy Elements, 255–59. Dordrecht: Springer Netherlands, 1985. http://dx.doi.org/10.1007/978-94-009-5325-3_33.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Leng, Melanie J., and Jonathan P. Lewis. "C/N ratios and Carbon Isotope Composition of Organic Matter in Estuarine Environments." In Applications of Paleoenvironmental Techniques in Estuarine Studies, 213–37. Dordrecht: Springer Netherlands, 2017. http://dx.doi.org/10.1007/978-94-024-0990-1_9.

Full text
APA, Harvard, Vancouver, ISO, and other styles

Conference papers on the topic "Carbon isotope ratios"

1

Close, Hilary, and Lillian Henderson. "Carbon isotope ratios of particulate organic carbon in the lower euphotic zone." In Goldschmidt2021. France: European Association of Geochemistry, 2021. http://dx.doi.org/10.7185/gold2021.7984.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Magdas, D. A., G. Cristea, A. Bot, and V. Mirel. "The use of carbon stable isotope ratios in drugs characterization." In PROCESSES IN ISOTOPES AND MOLECULES (PIM 2013). AIP, 2013. http://dx.doi.org/10.1063/1.4833745.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Stehmeier, Lester, Brad Magyar, Karlis Muehlenbachs, Xiaosu Lang, and Ajay Dalai. "Use of Stable Isotope Ratios to Determine the Origin of Coke Formed in Gas Turbines." In 2002 4th International Pipeline Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/ipc2002-27115.

Full text
Abstract:
Coke deposits can form in compression equipment on natural gas transmission lines. These deposits are a result of incomplete combustion due to poor fuel gas quality or incorrect equipment design and/or operation. There is an isotopic “signature” which is carried over from the fuel gas into the coke if incomplete combustion occurs, allowing the origin of the coke deposit to be identified. The use of a continuous flow gas chromatograph isotope ratio mass spectrometer (GC/IRMS) provides a convenient method for determining the isotopic composition of the components in the fuel gas. These ratios can then be used to identify if a correlation exists with the 13C/12C ratio of the coke sample. Previous projects in 1999 and 2000 demonstrated that the coke deposits found within gas turbines could be closely related to the incomplete combustion of the fuel gas. One outcome of that work was determining the value for having a good understanding of stable isotope signatures for gas entering the pipeline system. In 2000, fuel gas samples were obtained from various areas in the Alberta TransCanada collection system, their isotope ratios were measured and then used to produce coke. This work substantiated previous project work, reinforcing the isotopic relationship between coke and the source material. Current work is to produce a model to quantitatively relate the various components of the source material to coke deposits. This model could then be used as a tool to enhance the performance of the gas turbines. Detailed investigation into the sensitivity of stable carbon isotope measurements for identifying the source of coke deposits for a complete range of TransCanada fuel gas mixtures is presented.
APA, Harvard, Vancouver, ISO, and other styles
4

Rolle, Francesca, and Michela Sega. "Use of FTIR spectroscopy for the measurement of CO2 carbon stable isotope ratios." In 19th International Congress of Metrology (CIM2019), edited by Sandrine Gazal. Les Ulis, France: EDP Sciences, 2019. http://dx.doi.org/10.1051/metrology/201905002.

Full text
Abstract:
Carbon dioxide (CO2) is one of the most important long-lived anthropogenic greenhouse gases. Ocean, land and biosphere contribute to take up CO2 emissions, but approximately half of fossil fuel CO2 accumulates in the atmosphere. The study of isotopic composition of CO2 can give useful information for assessing and quantifying the uptake of CO2 in the environmental compartments, as well as for distinguishing natural from anthropogenic carbon in the atmosphere. In this work, an activity for the development of a Fourier Transform Infrared spectroscopy (FTIR) based method for δ13C-CO2 determination in CO2 in air mixtures is presented. The FTIR can be calibrated by a classical approach based on primary calibration gas standards, but an alternative calibration can be based on the generation of synthetic spectra, by means of radiative transfer calculation codes such as the Multiple Atmospheric Layer Transmission (MALT University of Wollongong, Australia). Another software (B-FOS) developed at the Bureau International des Poids et Mesures (BIPM) allows to interface MALT and the FTIR management software. This calibration approach is fast and reliable and can be used when the classical calibration based on reference gas mixtures might be demanding. The uncertainty obtained for δ13C-CO2 measurements is around 0.1 ‰, at a nominal CO2 mole fraction of 400 μmol mol-1 in air.
APA, Harvard, Vancouver, ISO, and other styles
5

Graniero, Lauren E., Donna Surge, and David P. Gillikin. "EVALUATING OXYGEN AND CARBON ISOTOPE RATIOS IN RANGIA CUNEATA AS A PALEOENVIRONMENTAL PROXY." In GSA Annual Meeting in Indianapolis, Indiana, USA - 2018. Geological Society of America, 2018. http://dx.doi.org/10.1130/abs/2018am-324245.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Milam, S. N., L. M. Ziurys, N. J. Woolf, and S. Wyckoff. "Carbon Isotope Ratios In Circumstellar Envelopes: Constraints For Nucleosynthesis And Galactic Chemical Evolution." In ASTROCHEMISTRY: From Laboratory Studies to Astronomical Observations. AIP, 2006. http://dx.doi.org/10.1063/1.2359552.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Beach, Sheryl, Tim Beach, Colin Doyle, Samantha Marie Krause, and Byron Smith. "A SYNTHESIS OF CARBON ISOTOPE RATIOS OF SOIL PROFILES IN THE MAYA LOWLANDS." In GSA Connects 2021 in Portland, Oregon. Geological Society of America, 2021. http://dx.doi.org/10.1130/abs/2021am-370786.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Ramos, Evan, Tomas Capaldi, and Preston Cosslett Kemeny. "HOW DO RIVER WATER LI ISOTOPE RATIOS RELATE TO CARBON TRANSFER DURING WEATHERING?" In GSA Connects 2022 meeting in Denver, Colorado. Geological Society of America, 2022. http://dx.doi.org/10.1130/abs/2022am-378571.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Furghieri Bylaardt Caldas, Priscila, Jonathan Snatic, and Kurt Kronenberger. "Quality Isotope Analysis at the Wellsite: Two Case Studies that Validate GC-C-IRMS Mud Gas Isotope Logging for Deepwater Exploration and Development." In SPE Annual Technical Conference and Exhibition. SPE, 2022. http://dx.doi.org/10.2118/210384-ms.

Full text
Abstract:
Abstract Geochemical analysis of gases produced during the drilling process is a common study on oil and gas exploration and development wells. This process typically includes the use of gas sample containers or other vessels that allow for single point samples to be collected for shipment to an offsite laboratory. Laboratories use high precision devices to obtain valuable information for reservoir characterization including stable carbon isotope ratios. In recent years there have been efforts to provide similar analyses during the drilling process, using ruggedized equipment suitable for wellsite deployment. This paper demonstrates that a Gas Chromatograph-Combustion-Isotope Ratio Mass Spectrometer (GC-C-IRMS) analyzer, using similar technology to what is most widespread in offsite laboratories (Dashti et al, 2018), can be successfully deployed to the rig site. This type of advanced gas analysis, commonly known as Mud Gas Isotope Logging (MGIL), provides continuous sampling of stable carbon isotopes of methane (δ13C1), ethane (δ13C2), and propane (δ13C3). The service, performed with a GC-C-IRMS analyzer, was proven and validated for an operator through two case studies. 98 The first case compares real time data with discrete gas sample tubes analyzed in an offsite laboratory. It shows how accurate results are possible, even with the presence of artificial gases generated by drill bit metamorphism (DBM) (Wenger et al, 2009). This example also demonstrates how the service enabled immediate analysis for operational decisions by indicating the presence of biodegraded thermogenic fluid. The second case study demonstrates how this wellsite service could corroborate the geological prognosis in a complex field influenced by salt tectonics. In this basin an upthrown reservoir changed the typical behavior observed in conventional wells of increased oil maturity with depth. Stable carbon isotope readings obtained in real time, integrated with cuttings analysis, indicated the presence of out of section lithology. This information allowed for estimating the thermogenic fluid maturity of reservoirs and diagnosis of geological formations that were out of sequence in terms of age (uplifted).
APA, Harvard, Vancouver, ISO, and other styles
10

McInerney, Francesca A., Robert S. Hill, Benjamin Birch, and Myall Tarran. "CANOPY CLOSURE IN CENOZOIC FORESTS OF AUSTRALIA USING CARBON ISOTOPE RATIOS OF FOSSIL CUTICLE." In GSA Annual Meeting in Seattle, Washington, USA - 2017. Geological Society of America, 2017. http://dx.doi.org/10.1130/abs/2017am-308586.

Full text
APA, Harvard, Vancouver, ISO, and other styles

Reports on the topic "Carbon isotope ratios"

1

Shorter, Joanne H., J. Barry McManus, David D. Nelson, Charles E. Kolb, Mark S. Zahniser, Ray Bambha, Uwe Lehmann, Tomas Kulp, and Stanley C. Tyler. A Widely Tunable Infrared Laser Spectrometer for Measurements of Isotopic Ratios of Carbon Cycle Gases. Office of Scientific and Technical Information (OSTI), January 2005. http://dx.doi.org/10.2172/836581.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Cohen, Shabtai, Melvin Tyree, Amos Naor, Alan N. Lakso, Terence L. Robinson, and Yehezkiel Cohen. Influence of hydraulic properties of rootstocks and the rootstock-scion graft on water use and productivity of apple trees. United States Department of Agriculture, 2001. http://dx.doi.org/10.32747/2001.7587219.bard.

Full text
Abstract:
This one year exploratory project investigated hydraulic architecture of apple dwarfing rootstocks. The hypothesis was that hydraulic conductance is correlated with rootstock vigor. A previous study of trees on three rootstocks in Israel showed that dwarfed trees used less water than un-dwarfed trees. Analysis showed that if the tree maintains leaf water potentials above minimum values, then this implies that the dwarfed trees have lower leaf conductance, which may also be the cause of dwarfing. The current project studied small 2-year old unworked rootstock trees, and full sized trees bearing commercial yields. In both cases hydraulic conductance was determined with two methods - the non-destructive evaporative flux (EF)-leaf water potential (L WP) method, and a destructive method in which water was forced through the plant at known pressure using the "high pressure flow meter" (HPFM). Detailed work allowed measurement of conductance of the rootstock-scion union. This was achieved both with the HPFM and with the EF-LWP methods, the former in the US and the latter in Israel. Direct measurements of leaf conductance were made, and carbon isotope ratios ( d ¹³ C) were determined for leaves sampled at the end of the season. The latter can indicate sustained differences in leaf conductance behavior. HPFM and EF-LWP methods did not give the same results. In the small plants results were similar in magnitude, but not significantly correlated. In large trees, EF- L WP measurements were a fraction of those obtained with the HPFM. The latter indicates that some of the xylem is not normally functional but transports water when pressurized. Additional experimental work targeted this result. Xylem was stained before and after perfusion with water at high pressure. This showed that at least for one rootstock a significant amount of xylem was blocked before perfusion. The "air method" for determining xylem vessel properties was improved and employed. Length, radius and density of xylem vessels of different rootstocks were found to be similar, and significant differences found were not clearly related to rootstock vigor. Measurements in the commercial orchard in Israel showed that the graft union in a dwarfing rootstock was a large obstacle for water transport (i.e. had a high resistance). This apparently led to low leaf conductance to water vapor, as indicated by lower d ¹³ C, which implies low internal CO ₂ concentrations. In the US orchard, d ¹³ C in 2001 was correlated with rootstock vigor, and significant differences were found in leaf conductance. However, the d ¹³ C differences were not observed in 2002, were opposite to those found in the Israeli orchard, and measurements of the graft union with the HPFM did not find large resistances. We speculate that the graft union is not necessarily a large impediment to water transport unless the scion starts to separate from the rootstock. It was concluded that significant differences in hydraulic conductance exist between different dwarfing rootstocks. These differences may be caused by differences in xylem properties and in the degree of cavitation, as well as resistance in the graft union. However, no general relationship to rootstock vigor was found. Therefore, hydraulic conductance alone cannot explain dwarfing, but may be one of two or more factors that lead to dwarfing. Future work should integrate more factors with hydraulic relations, e.g. nutrient and solute transport and production of hormones.
APA, Harvard, Vancouver, ISO, and other styles
3

Paterson, Andrew H., Yehoshua Saranga, and Dan Yakir. Improving Productivity of Cotton (Gossypsum spp.) in Arid Region Agriculture: An Integrated Physiological/Genetic Approach. United States Department of Agriculture, December 1999. http://dx.doi.org/10.32747/1999.7573066.bard.

Full text
Abstract:
Objectives: We seek to establish the basis for improving cotton productivity under arid conditions, by studying the water use efficiency - evaporative cooling interrelationship. Specifically, we will test the hypothesis that cotton productivity under arid conditions can be improved by combining high seasonal WUE with efficient evaporative cooling, evaluate whether high WUE and/or evaporative cooling are based on specific physiological factors such as diurnal flexibility in stomatal conductance, stomatal density, photosynthetic capacity, chlorophyll fluorescence, and plant water status. Genes influencing both WUE and evaporative cooling, as well as other parameters such as economic products (lint yield, quality, harvest index) of cotton will also be mapped, in order to evaluate influences of water relations on these parameters. Approach: Carbon isotope ratio will be used to evaluate WUE, accompanied by additional parameters to elucidate the relationship between WUE, evaporative cooling, and cotton productivity. A detailed RFLP map will be used to determine the number, location, and phenotypic effects of genes underlying genetic variation in WUE between cultivated cottons, as well as test associations of these genes with traits of economic importance such as harvest index, lint yield, and lint quality. Major Conclusions: Productivity and quality of cotton grown under well-watered versus water-limited conditions was shown to be partly accounted for by different quantitative trait loci (QTLs). Among a suite of physiological traits often found to differ between genotypes adapted to arid versus well-watered conditions, genetic mapping implicated only reduced plant osmotic potential in improved cotton productivity under arid conditions. Our findings clearly implicate OP as a major component of cotton adaptation to arid conditions. However, testing of further physiological hypotheses is clearly needed to account for additional QTL alleles conferring higher seed-cotton yield under arid conditions, such as three of the five we found. Near-isogenic lines being made for QTLs discovered herein will offer a powerful new tool useful toward identification of the underlying gene(s) by using fine-scale mapping approaches (Paterson et al 1990). Implications: Adaptation to both arid and favorable conditions can be combined into the same genotype. We have identified diagnostic DNA markers that are being applied to creation of such desirable genotypes. Simultaneous improvement of productivity (and/or quality) for both arid and irrigated conditions will require more extensive field testing and the manipulation of larger numbers of genes, reducing the expected rate of genetic gain These difficulties may be at least partly ameliorated by efficiencies gained through identification and use of diagnostic DNA markers. Genomic tools and approaches may expedite adaptation of crops to arid cultivation, help to test roles of additional physiological factors, and guide the isolation of the underlying genes that protect crop performance under arid conditions.
APA, Harvard, Vancouver, ISO, and other styles
4

Total organic carbon, extractable organic matter, rock-eval parameters, isoprenoid ratios, carbon preference index, and isotopic data from cuttings of the AMOCO Cathedral River #1 well. Alaska Division of Geological & Geophysical Surveys, 1986. http://dx.doi.org/10.14509/19199.

Full text
APA, Harvard, Vancouver, ISO, and other styles
You might also be interested in the extended bibliographies on the topic 'Carbon isotope ratios' for particular source types:
Journal articles Dissertations / Theses
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography