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 22 for “"Estuarine sediments"”.
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Tīmata whakaora, kickstarting recovery - Using bivalves to bioremediate degraded estuarine sediments
Estuarine soft sediment ecosystems worldwide are increasingly threatened by anthropogenic, land-derived and marine stressors that compromise their health and functionality with cascading effects on ecosystem services that they provide. Once degraded, natural recovery can take years due to the loss …
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THE BIOAVAILABILITY OF BROMINATED DIPHENYL ETHERS FROM URBAN ESTUARINE SEDIMENTS TO DEPOSIT-FEEDING INVERTEBRATES
… to determine the bioavailability of BDEs from sediments to deposit-feeding invertebrates in order to investigate potential transfer to higher trophic levels in estuarine environments. In field studies, accumulation of congeners in the Penta-BDE mixture was similar to PCBs with similar Kow. BDE …
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The effect of salinity on nutrient release from riverine and tributary estuarine sediments to the Chesapeake Bay under oxidizing and reducing conditions
… bench-scale microcosm studies of York River sediments and Occoquan Reservoir sediments were conducted. Seawater and freshwater were mixed in various ratios to simulate seasonal, salinity-varying environments in the Chesapeake Bay and its tributary estuaries. Experiments were conducted under …
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Holocene landscape history of southern Portugal
… with new palynological data from intertidal, estuarine sediments. In a region without natural lakes, estuarine sediments deposited during the post-glacial marine transgression represent a valuable resource for pollen analysis. Presented in the thesis are the methods and results of sedimentary …
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Denitrification response to nutrient enrichment in New Zealand estuaries
… in habitats dominated by muddy organic-rich sediments. Nutrient processing and denitrification in estuarine sediments represent important ecosystem functions regenerating nutrients for primary producers, and regulating the ability to remove excess terrestrially derived nitrogen. …
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Unifying ecosystem concepts and mercury biomagnification in an estuarine environment using stable isotopes (delta-carbon-13 and delta nitrogen-15).
… of delta13C and delta15N were obtained for sediments, suspended particulate matter (SPM), plants, and animals found in the Miramichi River Estuary (New Brunswick, Canada) and used to show the relationship between food web structure and patterns of mercury biomagnification. On a delta13C and …
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Late-quaternary environmental change at Eastbourne, East Sussex
… drilling rig, revealed extensive unconsolidated sediments down to a maximum depth of 33m. which consist of gravels, sand, silt and clay with restricted peat development. The history of the vegetation has been traced back to the Lateglacial when, it is argued, an unusually thermophilous community …
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Tidal velocity asymmetries and bedload transport in shallow embayments
Tidally forced circulation can cause a net near-bed transport of sediment when the tidal velocity is asymmetric about a zero mean (flood or ebb dominant) and the transport rate is nonlinearly related to velocity. The relationship between elevation and velocity is elucidated here to enable one to …
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A radiocarbon method and multi-tracer approach to quantifying groundwater discharge to coastal waters
… of 222Rn were dominated by artesian discharge. Estuarine 226Ra showed strong artesian influence, but also reflected the salt water SGD processes that controlled the other three radium isotopes. The flux of 228Ra seemed to reflect seepage from the terrestrial surficial aquifer as well as salt …
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A New Phase Speciation Leaching Procedure for the Determination of Metals in Oxic and Anoxic Sediments
… by human activities can accumulate in marine and estuarine sediments, where these metals are often sequestered until local environmental changes (e.g., redox, salinity, and/or pH) allow these elements to be reintroduced into the food web. In order to assess the extent of toxic trace element …
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In-Situ Geotechnical Characterization of Soft Estuarine Surficial Sediments Using a Portable Free Fall Penetrometer
… rare seabed soil conditions such as very soft estuarine sediments. This study aims to advance the analysis procedure of portable free fall penetrometers (PFFP) in soft subaquatic fine-grained soils with natural water contents greater than the liquid limit by estimating the undrained shear …
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Sediment Resuspension in a Microtidal Estuary: Causative Forces and Links with Algal Blooms
… resting cysts that accumulate in the bottom sediments and are thought to provide seed populations for future algal blooms when they are resuspended. When estuarine sediments are advected from a bed, other materials, such as pollutants, nutrients, and organic matter are also released into the …
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A trace element study of sediments from the Olifants River estuary, the Berg River estuary, and the off-shore Mud Belt
… and Berg river catchments by focusing on the sediments of the estuaries. The dominant industry in both catchments is agriculture and there exists relatively little urban sprawl. Two sediment samples taken from the offshore mud belt in the vicinity of the two river mouths were also analyzed. …
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Sediment deposition in the lower Hudson River estuary
… and to obtain the spatial distribution of estuarine deposits. Results show a high degree of spatial and temporal variability in sedimentation within the estuary. Two primary deposits are identified underneath the turbidity maximum for the estuary. Approximately 300,000 metric tons of …
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Mechanisms for accumulation and migration of technetium-99 in saltmarsh sediments
… of <sup>99</sup>Tc in sequential extracts from sediments. These methods have been used to collect data, which, along with trace and major element data have been used to interpret the mechanisms for <sup>99</sup>Tc input, migration and accumulation in saltmarshes. The inventory of <sup>99</sup>Tc …
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The influence of a petrochemical discharge on the bioturbation and erosion potential of an intertidal estuarine mudflat (Humber estuary, UK)
… on the structure and function of infaunal estuarine and marine communities is well studied but less is known of the influence of biota on sediment properties. Feeding and burrowing activity, locomotion, the production of faecal pellets and biological secretions (bioturbation) have important …
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Detection and Quantification of Single-walled Carbon Nanotubes in Environmental and Biological Samples for Evaluation of Fate, Transport and Bioaccumulation
… were spiked and subsequently extracted from estuarine sediments. SWCNTs were separated into different bands after DGU, primarily into two distinct horizons (one showed near infrared fluorescence, while the other did not). Two techniques,near-infrared spectroscopy (NIRF) and ICP-MS, were …
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Evolução geoquímica e ambiental dos sedimentos médio-estuarinos do Rio Goiana- Pernambuco, nos três últimos séculos
A evolução sedimentológica e geoquímica da Bacia Hidrográfica do Rio Goiana (Pernambuco-Brasil) é abordada nesta pesquisa cobrindo cerca de 300 anos de sua história. Os resultados são suportados por análises em testemunhos de perfil de fundo realizado no médio estuário deste rio, a 10 km da foz. As …
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