Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 24 for “"Stable Carbon Isotopes"”.
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Stable carbon isotopes in deep time : the diets of fossil fauna and hominids
… and application of a technique for extending carbon isotopic dietary tracing millions of years in time,. using the mineral phase of calcified tissues (apatite) as alternative sample material to collagen. The results reported here provide empirical evidence for the validity of the technique. …
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Growth, water use efficiency and stable carbon isotopes in commercial clones of Eucalyptus
… for improved water use efficiency and harvestable stem production under a limited water supply. This study investigated the effects of soil moisture availability on the growth and water use efficiency of 6 commercial clones of Eucalyptus commonly grown in South Africa with the aim of …
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Stable carbon isotopes and prehistoric diets in the Eastern Cape Province, South Africa
… in this thesis involves the measurement of stable carbon isotope ratios in human bone collagen as a means of reconstructing prehistoric diets. The sample population includes 67 skeletons of hunter-gatherers, pastoralists and agriculturalists from the Holocene of the Eastern Cape Province, …
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Plant xylem anatomy, dendrochronology and stable carbon isotopes as tools in rainfall reconstruction in Southern Africa
… on this method are the resolution of the radiocarbon dates, a suitable distribution of sites and a calibration curve for the species analysed.
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The physiology, mapping, and prediction of stable carbon isotopes: a proxy trait for water-use efficiency in maize
… security in the future. The relationship between stable carbon isotope ratios (δ13C) and WUE has been well characterized in C3 crops, but only recently gained attention in C4 plants. We observed high correlations between WUE and δ13C in greenhouse grown maize, which is important towards developing …
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The Spatial Distribution of Terrestrial Stable Carbon Isotopes in North America, and the Impacts of Spatial and Temporal Resolution on Static Ecological Models
… resolution on the modeling of terrestrial stable carbon isotopic landscapes (isoscapes). I model the distribution of leaf stable carbon isotope composition (delta<sup>13</sup>C) for the continent of North America at multiple temporal and spatial resolutions. I generate each …
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Stable isotope analysis of fauna and soils from sites in the Eastern Free State and Western Lesotho, Southern Africa : a palaeoenvironmental interpretation
This thesis examines the use of stable carbon isotopes as a means of reconstructing the palaeoenvironment of the Caledon River Valley of the eastern Free State, South Africa, and western Lesotho. In doing so, this work draws upon previous studies that have shown that the distinct distribution and …
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Carbon Cycling Dynamics Inferred from Carbon Isotope Sourcing in a Mid-Latitude Karst-Influenced River
<p>As ever-increasing levels of carbon dioxide alter the chemistry of the Earth’s atmosphere, understanding the global carbon cycle becomes increasingly important. A particularly important component is the riverine carbon cycle, as rivers are the primary conduits for dissolved inorganic carbon from …
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Differential Utilization of Allochthonous and Autochthonous Carbon By Aquatic Insects of Two Shrub-Steppe Desert Spring-Streams: A Stable Carbon Isotope Analysis and Critique of the Method
<p>Stable carbon isotope analysis, a technique that measures the ratio of stable carbon-12 to stable carbon-13 in abiotic and biotic components of ecosystems, was used to assess the differential utilization of autochthonous and allochthonous carbon by aquatic insects of two cold desert …
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The Role of Avifauna in Paleodiet Reconstruction : An Arctic Case Study
… of birds in paleodietary reconstruction based on stable isotope analysis, using faunal remains from Arctic contexts as a case study. In the Arctic, migratory birds and their eggs have been important seasonal resources for hunter-gatherer populations, and while evidence of their utilization in the …
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Miocene paleoenvironments and paleosol pH proxies.
… a strongly seasonal, dry subhumid climate. Stable carbon isotopes from pedogenic carbonates are consistent with a surprisingly large amount of C4 biomass, which was used in conjunction with the presence of microcharcoal grains and rodent community paleoecology to interpret an open-canopy …
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Seagrass-Mediated Carbonate Dissolution and Early Diagenesis in Bahamas Bank Sediments
… examining the role that seagrasses play in carbonate dissolution and early diagenesis of Bahamas Bank sediments. Three aspects of this problem are addressed: (1) stable carbon isotopes as an indicator of early diagenesis of carbonates, using results of a field study; (2) carbonate …
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A multifaceted approach to identifying targets for the improvement of water-use efficiency in Zea mays
… not able to screen large quantities of lines. Stable carbon isotope composition (δ13C) has been successfully used to breed for higher WUE in C3 crops. This has not been the case in C4 species due to their more complex photosynthetic mechanism. We present data demonstrating that leaf δ13C …
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Holocene vegetation history and environmental change in the forest-grassland mosaic of the Central Highlands of Madagascar
… this initiative can have benefits in terms of carbon storage and climate mitigation if carefully planned and managed, it can also cause biodiversity loss and degradation when afforestation takes place in areas that were previously open ecosystems, or where unsuitable species are used. …
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Evolution and ecology of C4 grasses: insights from carbon isotope analysis of grass pollen grains
C4 grasses account for >25% of global primary productivity and dominate tropical, subtropical, and warm-temperate grassland ecosystems. Because of limitations of conventional morphological and geochemical proxies, identification of C4 grasses in the fossil record is difficult. Thus, testing …
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Seasonal Influences on the Carbon-Water Relations in Ponderosa Pine Forests in the Northern Boundary of the North American Monsoon System
… are essential to better understand the water and carbon cycles, and tree-ring research has contributed valuable knowledge in this regard. There is a common understanding that moisture-stress has significant impacts on forested ecosystems and thereby on the global carbon and water cycles. Under …
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Aspects of Cyclic Sedimentation in the Upper Mississippian, Mauch Chunk Group, southern West Virginia and southwest Virginia
… driven by the annual monsoon. Total organic carbon (TOC) values are a proxy for annual climatic cycles. TOC contents are higher within intermonsoonal and lower within monsoonal components of annual cycles reflecting, respectively, lesser and greater dilution by terrestrial flux.
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Stable carbon and oxygen isotope investigation of Pleistocene growing-season paleoclimate using tree-ring cellulose from the Missinaibi Formation, Adam Creek, James Bay Lowland, Canada
… as precipitation and temperature. We analyzed stable isotopes of carbon (δ13Ccellulose) and oxygen (δ18Ocellulose) in early-wood and late-wood of five conifer sub-fossil wood samples from the Missinaibi Formation, which likely grew during the peak of Marine Isotope Substage (MIS) 5a (~82 kya) …
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The Application of Pedology, Stable Carbon Isotope Analyses and Geographic Information Systems to Ancient Soil Resource Investigations at Piedras Negras, Guatemala
… this Maya mystery. Pedological studies and stable carbon isotope analysis of soil organic matter, combined with Geographic Information Systems (GIS) are three tools that can be used to answer crucial questions as to how the Maya managed their soil resources.</p> <p>GIS maps that indicated …
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STRATIGRAPHIC FRAMEWORK AND QUATERNARY PALEOLIMNOLOGY OF THE LAKE TURKANA RIFT, KENYA
… density, magnetic susceptibility, total organic carbon, total inorganic carbon, core lithology, and scanning XRF data from sediment cores that were chronologically constrained by radiocarbon dates. Two desiccation events occurred at 18.5 and 17 ka when the lake was at least 100 m lower than …
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