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Influence Of Permafrost Thaw, Microtopography, And Precipitation On Methane Cycling In Northern Peatlands, Clarice Rachelle Perryman
Influence Of Permafrost Thaw, Microtopography, And Precipitation On Methane Cycling In Northern Peatlands, Clarice Rachelle Perryman
Doctoral Dissertations
Northern peatlands are both globally important carbon (C) stores and sources of methane (CH4). The impacts of climate change including warming, changing precipitation and hydrology, shifts in vegetation, and thawing permafrost may increase the vulnerability of the northern peatland C stock, including the amount of C lost to the atmosphere as CH4. Variation in peatland water table depth strongly influences CH4 cycling, as water table levels largely control redox conditions and therefore rates of anaerobic CH4 production (methanogenesis) and aerobic CH4 oxidation (consumption, methanotrophy). As CH4 emissions reflect the balance of methanogenesis and methanotrophy, changes in water table depth due …
Carbon Emissions From Streams And Rivers: Integrating Methane Emission Pathways And Storm Carbon Dioxide Emissions Into Stream And River Carbon Balances, Andrew Robison
Doctoral Dissertations
River networks play an important role in elemental cycling at watershed, regional, and global scales. They not only serve as pipes that transport elements from land to sea, but also as complex processers that can significantly modify the timing, form, and magnitude of these elemental fluxes. For example, recent studies have shown that river networks contribute significantly to the global carbon cycle by emitting greenhouse gases like carbon dioxide (CO¬2) and methane (CH4) to the atmosphere. However, we currently do not fully understand the controls on GHG emissions from river networks, particularly what drives the variability of emissions across space …
Investigating The Spatial And Temporal Scale Variability Of Ebullitive Flux From A Subarctic Thaw Pond System, Sophia Burke
Investigating The Spatial And Temporal Scale Variability Of Ebullitive Flux From A Subarctic Thaw Pond System, Sophia Burke
Doctoral Dissertations
Arctic regions are experiencing more rapid warming than other parts of the world, leading to destabilization of carbon (C) that has been sequestered in permafrost, especially in peatlands where the C content of the peat is very high. More frequent incidence of thaw in permafrost peatlands is leading to the development of small thaw ponds that are known to be sources of methane (CH4) to the atmosphere, yet there is a lack in long-term studies of CH4 emission from these formations. This is of concern because CH4 has thirty-two times the global warming potential of carbon dioxide over a one-hundred-year …
Adsorption And Diffusion Of Gases In Nano-Porous Materials, Nethika Sahani Suraweera
Adsorption And Diffusion Of Gases In Nano-Porous Materials, Nethika Sahani Suraweera
Doctoral Dissertations
In this work, a systematic computational study directed toward developing a molecular-level understanding of gas adsorption and diffusion characteristics in nano-porous materials is presented. Two different types of porous adsorbents were studied, one crystalline and the other amorphous. Physisorption and diffusion of hydrogen in ten iso-reticular metal-organic frameworks (IRMOFs) were investigated. A set of nine adsorbents taken from a class of novel, amorphous nano-porous materials composed of spherosilicate building blocks and isolated metal sites was also studied, with attention paid to the adsorptive and diffusive behavior of hydrogen, methane, carbon dioxide and their binary mixtures. Both classes of materials were …