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 90 for “"carbon isotopes"”.
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The Biogeochemistry of Carbon Isotopes in Local Lakes
… of organic matter all involve the transfer of carbon among the carbon-bearing species in the systems. These biogeochemical processes also fractionate the carbon isotope composition, which results in changes to the carbon isotope composition of the dissolved inorganic carbon (DIC) pool. This …
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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
… associated with sampling for stable carbon isotope ratios (δ¹³C) within a eucalypt canopy and the potential use of δ¹³C in plant tissues as a tool for ranking clonal water use efficiencies.
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Exploring high-resolution carbon isotopes in archaeological charcoal as a rainfall seasonality proxy
… proxy (SPP) based on high-resolution carbon isotope profiles — successfully applied to evergreen wood in the Northern Hemisphere — can be used to reconstruct rainfall seasonality from South African archaeological Proteaceae (angiosperm) and Podocarpaceae (gymnosperm) charcoal. Modern …
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Stable carbon isotopes and prehistoric diets in the Eastern Cape Province, South Africa
… 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, South …
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A study of the remineralization of organic carbon in nearshore sediments using carbon isotopes
A study of the remineralization of organic carbon was conducted in the organic-rich sediments of Buzzards Bay, MA. Major processes affecting the carbon chemistry in sediments are reflected by changes in the stable carbon isotope ratios of dissolved inorganic carbon (ΣCO2) in sediment pore water. …
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A study of the remineralization of organic carbon in nearshore sediments using carbon isotopes
A study of the remineralization of organic carbon was conducted in the organic-rich sediments of Buzzards Bay, MA. Major processes affecting the carbon chemistry in sediments are reflected by changes in the stable carbon isotope ratios of dissolved inorganic carbon (XCO2) in sediment pore water. …
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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
… 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 an …
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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 delta<sup>13</sup>C …
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Investigation the use of oxygen and carbon isotopes and sclerochronology on Turbo sarmaticus and Donax serra for palaeoenvironment reconstruction at Pinnacle Point, South Africa
This thesis investigates the validity of oxygen isotope analysis for the gastropod Turbo sarmaticus (operculum and shell) and the bivalve Donax serra to reconstruct sea surface temperatures. These are the species most commonly retrieved from archaeological assemblages of the South Coast of South …
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Elucidating Temporal Variability in Organic Matter Sources and Cycling in Tropical Rivers
Tropical rivers are large sources of carbon to the atmosphere and the ocean. The composition of riverine organic matter (OM) affects the size of these fluxes by governing how much carbon will be returned to the atmosphere while in transit versus exported to the ocean, where carbon can be …
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Investigating evidence of high frequency glacial eustacy in the Lower Mississippian (Tournasian) Lodgepole Formation of southwest Montana : insights from conodont oxygen isotopes
This study focuses on high-frequency, subtidal-carbonate cycles (1-8 m thick) within the Woodhurst Member of the Lower Mississippian Lodgepole Formation of southwest Montana. We combined conodont-oxygen isotopes (δ18Oapatite¬) and carbonate-carbon isotopes (δ13Ccarb) with cyclostratigraphy of …
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Igneous intrusions and thermal evolution in the Raton Basin, CO-NM: contact metamorphism and coal-bed methane generation
… outcrops were analyzed by vitrinite reflectance, carbon isotopes and petrography. Reflectance values at sill contacts are elevated over a wider zone than for dikes. Coal [delta]¹³C values increase by 1% approaching the contacts of dikes and decrease by approximately 1.5% at sills due to the …
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Climate and habitat reconstruction of hominid sites in northern China with paleosol stable isotopes
… isotope geochemistry of paleosols, including carbon isotopes of soil organic matter and pedogenic carbonates, and oxygen isotopes of pedogenic carbonates, can provide evidences for tree:grass ratios, air surface temperature and soil moisture conditions. These data can also help resolve …
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Geochemically tracing the intermediate and surface waters in the Tasman Sea, southwest Pacific
… the water masses. Secondly, by using oxygen and carbon isotopes from sediment cores to study changes in Antarctic Intermediate Waters (AAIW) over the late Quaternary in the north Tasman Sea. ¶ The geochemical tracers highlight the presence of three separate intermediate water masses in the …
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Geochemically tracing the intermediate and surface waters in the Tasman Sea, southwest Pacific
… the water masses. Secondly, by using oxygen and carbon isotopes from sediment cores to study changes in Antarctic Intermediate Waters (AAIW) over the late Quaternary in the north Tasman Sea. ¶ The geochemical tracers highlight the presence of three separate intermediate water masses in the …
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A Systematic and Taphonomic Analysis of Late Pleistocene Cervid Remains and Isotopic Paleoecology of Herbivores from Guy Wilson Cave, Southern Appalachians, Tennessee
… with a focus on carnivore utilization, and 3) carbon isotopes from cervid and herbivore tooth enamel (δ<sup>13</sup>C). Systematic identification reveals that there are at least three cervid species in the cave fauna based on fossil remains: <em>Odocoileus virginianus</em>, <em>Rangifer …
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Rates of natural climate change : a study of speleothems
… caves. The start of growth, growth rate, oxygen isotopes, carbon isotopes and luminescence intensity in two speleothems from southern Ireland provide high-resolution records of rapid palaeoclimate changes in that region during the Late Glacial. Several of these palaeoclimate proxies appear to be …
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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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