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 “"Permafrost thaw"”.
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Tracing the New Carbon Cycle From Plant Inputs to Microbial Outputs Across an Arctic Permafrost Thaw Gradient
… rapid warming due to climate change, causing permafrost C stocks to thaw and become available for decomposition. Since these systems store approximately 1.7 times the amount of C currently in the atmosphere, its decomposition and release as CO2 and CH4 could have profound effects as a positive …
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A Paleolimnological Investigation into the Ecological Impacts of Permafrost Thaw Slumping on Cladocerans (Branchiopoda, Crustacea) in the Mackenzie Delta Region (Northwest Territories, Canada)
… explores the ecological impacts of retrogressive thaw slumping on cladocerans (Branchiopoda, Crustacea) in Mackenzie Delta Region (Northwest Territories, Canada) lakes using paleolimnological techniques to answer the following questions: 1) Does thaw slumping increase UV exposure of Chydorus? 2) …
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Novel disturbance regimes in the Arctic: paleoecological perspectives on fire and thermo-erosion from Alaskan tundra
… On longer timescales, fires can enhance permafrost thaw by reducing surface albedo, enhancing surface roughness, and facilitating shrub expansion and snow drift, which can alter the soil thermal regime. Thus, these novel disturbance regimes may result in more rapid ecosystem changes in …
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Observing Seasonal Cycles in Greenhouse Gas Fluxes with Automatic Flushing Chambers in a Low-Arctic Lake
… causing a changing climate which is affecting permafrost thaw, sea ice melt, and changing hydrological dynamics. Lakes in the Arctic and sub-Arctic regions are increasingly recognised as important actors in the global carbon budget, acting as both sources and sinks of carbon dioxide (CO₂) and …
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Distribution and behavior of trace metals in the subterranean estuary of an Arctic coastal lagoon
… With warming in the Arctic and the subsequent permafrost thaw, the relative importance of submarine groundwater discharge (SGD) to ocean chemical budgets will grow. In this study, we examined the distribution of select trace metals (Fe, Mn, V, U, Mo and Ba) in the STE, lagoon surface waters, …
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Distribution and behavior of trace metals in the subterranean estuary of an Arctic coastal lagoon
… With warming in the Arctic and the subsequent permafrost thaw, the relative importance of submarine groundwater discharge (SGD) to ocean chemical budgets will grow. In this study, we examined the distribution of select trace metals (Fe, Mn, V, U, Mo and Ba) in the STE, lagoon surface waters, …
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The hydrological and limnological characterization of two Canadian water catchments sensitive to anthropogenic influences: Crawford Lake, Ontario and Old Crow Flats, Yukon
… landscape changes, including shoreline permafrost slumping, rapid thermokarst lake drainage, shrub encroachment, water level changes, and forest fires. Long-term analysis (2007 –2009 and 2015 – 2019 CE) of the hydrological response to these landscape changes have shown trends of …
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Tracking carbon fluxes across ocean interfaces using dissolved gas observations
… carbon pump (BCP) and carbon release from Arctic permafrost. This thesis focuses on dissolved gases as tracers and drivers of these processes through both autonomous and field-based observations. It encompasses (i) improvements to sensor-based measurements of O2, (ii) the use of these measurements …
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Arctic Char Otolith Records of Recent Limnological Change in High Arctic Lakes
… in recent years due to climate warming and permafrost thaw. These changes have the potential to impact organisms residing in these environments such as Arctic Char (Salvelinus alpinus) which represent the top predatory fish in Arctic lakes. Otoliths, the inner ear bones of fish, offer a …
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Biogeochemical and ecological responses to warming climate in High Arctic polar deserts
… amount of soil organic carbon (SOC) in the permafrost and to emit higher amounts of the main greenhouse gases (GHGs) than previously expected. However, the mechanisms of the main GHG production are not clear. Furthermore, polar deserts are predicted to dramatically transform under rapidly …
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Tracking carbon fluxes across ocean interfaces using dissolved gas observations
… carbon pump (BCP) and carbon release from Arctic permafrost. This thesis focuses on dissolved gases as tracers and drivers of these processes through both autonomous and field-based observations. It encompasses (i) improvements to sensor-based measurements of O₂, (ii) the use of these measurements …
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The impacts of thermokarst activity on a stream in the McMurdo Dry Valleys
… discovery of extensive thermokarst degradation (permafrost thaw features) along the banks of Crescent Stream in Taylor Valley. In 2012, a large stretch of the West Branch of Crescent Stream was found to have significant thermokarst bank failures, while the adjacent East Branch was found to be …
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Polonium-210 in Freshwater Environments: Analytical Advances, Predictive Modelling, Food Web Transfer and Dose Assessment
… suggest that climate driven processes such as permafrost thaw and lake browning may further influence ²¹⁰Po behaviour in freshwaters. A strong radiological association between ²¹⁰Po and ²¹⁰Pb was also confirmed for the abiotic compartments. Food web analyses revealed that water chemistry, …
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Spatiotemporal dynamics of carbon cycling and thermokarst in response to climate and fire-regime changes in the Arctic tundra biome
… tundra ecosystems, including soil carbon stock, permafrost stability and vegetation types. However, it remains poorly understood how tundra ecosystems will feedback to the combined forces of changing climate and fire disturbance. In this study, I integrated paleoecology, numerical modeling and …
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Tracing carbon flows through Arctic and alpine watersheds
… during peak biomass, fall senescence, and spring thaw to assess interactive effects of glucose amendment and season. We also captured legacy responses to amendment by assessing the fate of glucose over short, intermediate, and longer-term periods. We found that glucose conversion to CO2 was twice …
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Subarctic ecosystem responses to climate, catchment and permafrost dynamics in the Holocene
… assesses aspects of the wetland development, permafrost dynamics and associated changes in carbon and nutrient cycling of the Stordalen Mire in northern Sweden. Various ecological and biogeochemical analyses of one peat and two lake sediment sequences were conducted, including analyses of …
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Effect of mass wasting on soil organic carbon storage and coastal erosion in permafrost environments
Accelerated permafrost thaw under the warming Arctic climate can have a significant impact on Arctic landscapes. Areas underlain by permafrost store high amounts of soil organic carbon (SOC). Permafrost disturbances may contribute to increased release of carbon dioxide and methane to the …
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The seasonal dynamics of Arctic surface hydrology in permafrost environments
… cal cycling. In the Arctic and sub-Arctic permafrost zones, rising air temperatures are warming, and in some regions even thawing, the frozen ground. Permafrost is a carbon sink. The thermal state of the ground therefore has important implications on carbon exchange with the atmo- sphere. …
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Terrestrial Si dynamics in the Arctic: a study on biotic and abiotic controls
… regions of the Arctic tundra and continuous permafrost region. By combining results obtained through soil chemical analysis with literature review this thesis provide a conceptual framework for how climate change may alter the biological component of terrestrial Si cycling in Arctic regions …
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