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 25 for “"atmospheric CO2 concentrations"”.
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Impacts of global warming and rising atmospheric CO2 concentrations on physiology, development and productivity of Midwestern crops
… greenhouse gases in the atmosphere, particularly CO2, drives increases in the global surface temperatures and is already impacting life on Earth. The impact of these changes on agro-ecosystem is particularly important as we rely on agriculture for food, fiber, and renewable energy, the demand for …
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An Integrated Modeling Study of Ocean Circulation, the Ocean Carbon Cycle, Marine Ecosystems, and Climate Change
… Oceans. Finally, I quantify that increased atmospheric CO2 concentrations would be mainly responsible for future ocean acidification, including lowering in ocean pH and sea water saturation state with respect to carbonate minerals. The consideration of climate change produces a second-order …
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Uncertainty in atmospheric CO₂ concentrations from a parametric uncertainty analysis of a global ocean carbon cycle model
… This model for the solubility sink of excess atmospheric CO2 has many enhancements over the more simple 0-D and 1-D box-diffusion models upon which it is based, including latitudinal extension of mixed-layer inorganic carbon chemistry, climate-dependent air-sea exchange rates, and mixing of …
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Understanding Carbon Uptake Using Multi-Scale Novel Remote Sensing Techniques
… in regulating interannual variability of atmospheric CO2 concentrations. Remote sensing can be used to monitor multiple aspects of vegetation dynamics as well as its sensitivity to climate to improve dryland carbon uptake estimations. The thesis integrated existing cutting-edge remote …
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Examining the Role of Climate, Carbon and Nitrogen Interactions in the Terrestrial Biosphere
… in global environmental factors including atmospheric CO2 concentrations, N deposition, climate and land use. This study shows (i) The terrestrial C sink from CO2 fertilization effect is reduced due to the limitation of N (by 0.53GtC/yr in the 1990s), (ii) the positive feedback between …
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LATE MIOCENE AND PLIOCENE PALEOCEANOGRAPHY OF THE LOW LATITUDE NORTHERN HEMISPHERE AND ITS IMPLICATIONS FOR FUTURE CLIMATE CHANGE
… ocean gateways and reorganization of oceanic and atmospheric circulation structure have helped shape the climate system into its present form. This study provides a reconstruction of sea surface temperature (SST), ocean circulation, and thermal structure of the LL eastern Pacific and North …
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Atlantic Ocean circulation at the Last Glacial Maximum : inferences from data and models
This thesis focuses on ocean circulation and atmospheric forcing in the Atlantic Ocean at the Last Glacial Maximum (LGM, 18-21 thousand years before present). Relative to the pre-industrial climate, LGM atmospheric CO2 concentrations were about 90 ppm lower, ice sheets were much more extensive, and …
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Response of pteropod and related faunas to climate change and ocean acidification
… Laboratory studies have shown that increased pCO2, leading to decreased pH and low carbonate concentrations, has a negative impact on the ability of pteropods to calcify and maintain their shells. This study presents the micropalaeontological analysis of marine cores from the Caribbean Sea, …
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Tree Growth and Carbon Balance in a Temperate Forest Exposed to Elevated Carbon Dioxide for Eight Years
… on the global carbon cycle. Increases in atmospheric CO2 concentrations strongly influence plant carbon uptake and because forests account for the bulk of terrestrial productivity the future role of forests in the carbon cycle is a subject of current scientific interest. This research …
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A multifaceted approach to identifying targets for the improvement of water-use efficiency in Zea mays
… the transpiration efficiency and WUE of maize. Atmospheric CO2 has increased over the past decade and projections show greater increases in the future. Understanding how stomata will respond to high atmospheric CO2 concentrations and accompanying environmental changes is necessary for the …
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Electrochemical Routes for Capture and Utilization of CO2
The rapid rise in atmospheric CO2 concentrations presents a critical challenge to global climate stability, necessitating the development of energy-efficient, scalable, and economically viable carbon capture and utilization (CCUS) technologies. This thesis advances integrated electrochemical and …
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Not all models are created equal: assessing parameterisations of iron dynamics in ocean biogeochemical models
… carbon sequestration as well as modulating atmospheric CO2 concentrations. As iron is such a vital nutrient for biogeochemical processes it is often included as a variable in ocean biogeochemical models. In representing the iron cycle, biogeochemical models must parameterise the major …
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A long-term record of the physiological plasticity of stomatal condactance in Proteaceae
… A principal response of plants to increases in atmospheric CO2 concentration and changing rainfall regimes is to minimise water loss by reducing stomatal conductance (gs) and simultaneously increasing intrinsic water-use efficiency (iWUE). Plasticity in these two physiological traits may enhance …
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An Analytical Study of Air-Sea CO2 Gas Exchange in the Northwest Mississippi Bight Region
<p>With the continued increase of carbon dioxide (CO2) emissions, researchers are concerned with accumulation of excess CO2 within the atmosphere. The ocean is an important sink for the drawdown of atmospheric CO2 concentrations. Due to high spatial and temporal variability, CO2 fluxes in the …
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Carbon dioxide emissions from selected soils in Zambia : effects of nitrogenous fertilizer and agricultural lime.
Soils can serve as sources or sinks of atmospheric carbon dioxide (CO2) depending on how they are managed. As atmospheric CO2 concentrations continue to rise there is need to find ways of reducing CO2 emissions from soils. This study was conducted to assess the effects of applying agricultural lime …
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Quantifying terrestrial ecosystem carbon dynamics with mechanistically-based biogeochemistry models and in situ and remotely sensed data
… the carbon fluxes but it fails to consider the atmospheric CO2 effect given its important physiological role in carbon assimilation. In the second chapter, we consider the effect of atmospheric CO2 using an artificial neural network (ANN) approach to upscale the AmeriFlux tower of net ecosystem …
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The Ups and Downs of the Holocene: Exploring Relationships between Global CO2 and Climate Variability in the North Atlantic Region
… to examine the relationship between climate and atmospheric CO2 concentrations through rapid climate changes during the Holocene. Climate was reconstructed using high-resolution, radiocarbon dated, lake sediment geochemical proxies (magnetic susceptibility, loss-on-ignition, total …
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Process-based simulation of the terrestrial biosphere : an evaluation of present-day and future terrestrial carbon balance estimates and their uncertainty
… terrestrial ecosystems slows the growth rate of atmospheric CO2 concentrations, and thereby reduces the impact of anthropogenic fossil fuel emissions on the climate system. Changes in climate and land use affect terrestrial biosphere structure and functioning at present, and will likely impact on …
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Living in a changing world: an integrated approach to documenting and understanding medium to long-term vegetation changes in three contrasting land use systems in a mesic savanna, Nothern Zululand, South Africa
… driver such as changing climate or increasing atmospheric CO2 concentrations. The rate and extent of vegetation changes were measured and recorded in areas that have remained under communal, commercial and conservation tenure for approximately the past century. Changes in vegetation were …
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Dynamics of water, carbon, and nitrogen in forest and alpine tundra ecosystems in the Pacific Northwest and the Rocky Mountains of the U.S. under future climate change
… with other disturbances, such as changes in atmospheric deposition or land disturbance. In this research, I tested the hypotheses that 1) climate change at high elevation watersheds in the western U.S. will result in physiological stress on vegetation that is adapted to its native climate, …
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