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 191 for “"sediment-cores"”.
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A late-Quaternary record of environmental variability from lake sediment cores, Wind River Range, Wyoming
1 PDF file (viii, 227 pages)
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Laser-based method for black carbon determination in lake sediment cores and black carbon deposition in Greenland since 300 CE
… records of BC, such as those measured in ice cores, can be used to reconstruct forest fire history over past millennia. Thus, quantifying BC's role in the climate system is important for understanding both fire history and Earth's radiative budget. This study presents a new method for …
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The Geochemistry of Submerged Marine Landscapes: Lipid, Isotopic and Inorganic composition of Sediment Cores from the Palaeo-landscape of Doggerland
… as Doggerland. 85 samples from six different cores, which were collected from this prehistoric landscape, were studied using multi proxy -organic and inorganic- geochemical methods. Thermal analysis determined the organic matter and carbonate content, which were utilized as characterizing …
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A late quaternary history of Agulhas-Benguela interactions from two sediment cores on the western continental slope of South Africa
… through the multiproxy study of two giant piston cores, MD962080 and MD962084, retrieved from the Agulhas Bank and Olifants River continental slopes of South Africa. The stable oxygen isotope record of the benthic foraminifer, Cibicidoides wuellerstorfi, and the planktonic taxon, Globorotalia …
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Use of MicroCT to determine the functional ecology of intertidal infauna
… technique by Mazik et al. (2008), by stabilizing sediment cores and using μCT scanning to obtain burrow parameters along a salinity and elevation gradient. In-situ agar stabilization reduced the collapse of large infaunal biogenic features in sediment cores on intertidal mudflats and accurately …
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Seagrass Carbon Standing Stock in the Northern Gulf of Mexico: The Role of Seagrass Beds in Mississippi as Potential Blue Carbon Sinks
… widely studied, knowledge gaps exist on the sediment carbon standing stock of seagrasses. I aim to better understand how persistent seagrass meadows surrounding barrier islands in the northcentral Gulf of Mexico contribute to long-term blue carbon standing stocks. Subaqueous sediment cores …
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Time-scales of passive tracers in the ocean with paleoapplications
… is critical when interpreting paleodata from sediment cores. Surface-injected tracers are not spreading instantaneously or uniformly throughout the ocean. To obtain insights into these time-scales, a transition matrix is used to compute successive states of a passive tracer concentration in …
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Sediment deposition in the lower Hudson River estuary
This study uses geophysical and sedimentological data collected from the Lower Hudson River estuary to identify the depositional response of the estuary to high river discharge events. Erosional and depositional environments in the estuary are identified through the use of side-scan sonar, bottom …
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Lake and fjord sediments as Late Glacial to Holocene environmental and climate archives of the southernmost Andes at 53°S, Chile
… sites on the basis of parametric echo sounding sediment profiles in the fjords of the Gran Campo Nevado area. The stratigraphy of the sediment cores is based on 14C-AMS ages and tephrachronology. Sedimentological and geochemical characteristics were investigated in order to determine sediment …
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Distribution of post-Last Glacial Maximum Sedimentary Deposits in the Amundsen Sea, Antarctica, from Subbottom Seismic Profiles
… the austral summers of 2019 and 2020 reveal sediment that has been delivered from two major glaciers: Thwaites and Pine Island. Sediments transported by Thwaites and Pine Island Glaciers have predominantly been studied through analysis of sediment cores which have been collected in specific …
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Structural Characterisation and the Diagenetic Pathways of C25 Highly Branched Isoprenoid Hydrocarbons
… hydrocarbons have been widely reported in recent sediments. It is known that two species of diatomaceous algae, the diatoms Haslea ostrearia and Rhizosolenia setigera are able to biosynthesise C25 HBI alkenes. Large scale cultures of H. ostrearia studied previously, allowed isolation and …
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Sediment Phosphorus Cycling in a Managed System Irondequoit Bay, N.Y.
… Bay, NY, an embayment of Lake Ontario. Sediment core incubation experiments and phosphorus water column profiles were used to quantify the release rate of phosphorus from the deepwater sediments of Irondequoit Bay during summer periods of low hypolimnetic oxygen. The top 25 cm of …
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Investigating Environmental Change Due To Hypoxic Conditions On The Louisiana Continental Shelf: A Geochemical Approach
… Multiple geochemical proxies on a suite of sediment cores from the LA shelf provide a record of environmental change that parallels the onset of hypoxic conditions over the last century and prior to anthropogenic influences. The sedimentary record for the last century shows a shift from …
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An inverse approach to understanding benthic oxygen isotope records from the last deglaciation
… shells of benthic organisms recovered in ocean sediment cores. This thesis develops and applies an inverse framework for understanding deglacial oxygen isotope records derived from sediment cores in terms of the Green functions of ocean tracer transport and ocean mixed layer boundary conditions. …
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An inverse approach to understanding benthic oxygen isotope records from the last deglaciation
… shells of benthic organisms recovered in ocean sediment cores. This thesis develops and applies an inverse framework for understanding deglacial oxygen isotope records derived from sediment cores in terms of the Green functions of ocean tracer transport and ocean mixed layer boundary conditions. …
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An investigation of metal contaminants in sediments of Arctic Svalbard: Inferences for sources and transport pathways
… identified throughout the Arctic’s sedimentary environment. The aim of this research was to investigate further heavy metal contamination, specifically within the sediments of the Svalbard region, and the Barents Sea area, within the Arctic. Ten sediment cores were taken for analysis …
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Paleolimnological Reconstruction of Long-Term Trends in Phototrophic Communities in Prairie Reservoirs
… investigations of Lake Diefenbaker sediments were conducted to assess spatial and temporal environmental trends. Lines of investigation included trends in organic input and changes within the phototrophic (algal) community, with a primary focus on cyanobacteria and associated toxins. …
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Determining the distribution and fate of mercury in sediments of the Cataraqui River at Kingston, Ontario
… (THg) concentrations in depth profiles of 21 sediment cores within the inner harbour. THg in pore waters was measured in some selected cores along with methylmercury (MeHg), and total organic carbon measured as % Organic Matter (OM). Results show that the spatial distribution of THg in the …
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Ecological resilience at semi-arid and temperate boundaries of the Mediterranean-type Fynbos Biome, South Africa, during the Holocene
… determine biome resilience. This study sourced sediment cores directly from presentday fynbos-succulent karoo (semi-arid) and fynbos-afrotemperate forest biome boundaries to emphasise ecological dynamics. Fossil pollen, spores and charcoal were extracted from radiocarbon dated sediment cores to …
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A multi-proxy approach to investigating the latest Holocene (~4,500 yrs. BP) vegetational history of Catahoula Lake, Louisiana
<p>A multi-proxy investigation of sediments examined from Catahoula Lake, Louisiana has provided a record of late-Holocene vegetational changes, related to both hydrology and climate. This study integrates data from phytoliths, pollen, stable isotopes, magnetic susceptibility, and core sediment …
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