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 166 for “"Atmospheric CO2"”.
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A comprehensive global 3D model of delta-18O in atmospheric CO2
… global 3D model to simulate delta-18O in atmospheric CO2. The aim is to disentangle this isotope signal which offers the potential to determine the CO2 gross fluxes of the terrestrial biosphere. Model surface processes have been validated against regional experiments while the integrated …
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The effects of elevated atmospheric CO2 on below ground processes in fynbos and C4 ecosystems
This thesis investigated ways in which elevated atmospheric carbon dioxide (CO2) concentrations influence the plant: soil interface and soil biological processes. The studies focused on microbial populations associated with the plant rhizosphere, and how these responses could feed into changes in …
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On the role of the Southern Ocean in the global carbon cycle and atmospheric CO2 change
… about the causes of glacial-interglacial CO2 variations demonstrates our incomplete grasp of fundamental processes that govern our climate and thus one of the foremost problems in palaeoceanography and Earth System Science regards the mechanism(s) responsible for natural changes in …
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Effects of Elevated Atmospheric CO2 on Root Growth, Turnover and Decomposition in a Scrub Oak Ecosystem
<p>Atmospheric carbon dioxide levels are increasing and predicted to double this century. The implications of this rise on vegetation structure and function are not well understood. Measurement of root growth response to elevated atmospheric carbon dioxide is critical to understanding soil carbon …
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Hydrogen peroxide from photosynthesis: Theory and experiments linking elevated atmospheric CO2 with C3 plant chemical defense
Elevated atmospheric CO2 alters C3 plant chemical defense for reasons that remain unclear. To explain the influence of elevated CO2 on plant chemical defense, this dissertation proposes, then tests, the hypotheses that: 1. C3 plant chloroplasts exert control over chemical defense against biotic …
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Will Nitrogen fixers benefit from rising Atmospheric CO2? The response of Podalyria Sericea to elevated CO2
… communities and ecosystems to rising levels of atmospheric CO2, the response of individual plants under natural conditions needs to be determined. Podalyria sericea, a fynbos legume, was grown in a greenhouse under ambient (35 Pa) and elevated (70 Pa) CO2 partial pressure for 18 months. Growth, …
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Evaluating the Effect of Composition, Structure and Functionality on Atmospheric CO2 Adsorption in Porous Solid Sorbents
Carbon dioxide (CO2) is the most abundant greenhouse gas in the atmosphere, and it is estimated to be responsible for approximately two thirds of the total global warming effect caused by anthropogenic gas emissions. Meeting the Paris Agreement objective of temperature increases well below 2°C …
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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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Effects of Elevated Atmospheric CO2 on Root Dynamics, Biomass and Architecture in a Scrub-Oak Ecosystem at Kennedy Space Center, Florida
… Open-top chambers have been exposed to elevated atmospheric CO<sub>2</sub> for the past eleven years at Kennedy Space Center, Florida. No significant sustained CO<sub>2</sub> treatment effects were observed in fine root length density, due to root closure. Root density at lower depths increased …
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The Combined Effect of Ocean Acidification and Euthrophication on water pH and Aragonite Saturation State in the Northern Gulf of Mexico
Rising atmospheric carbon dioxide (CO2) concentrations are increasing the rate at which anthropogenic CO2 is accumulating in the ocean, and thereby acidifying ocean water. However, accumulation of anthropogenic CO2 is not the only process affecting coastal oceans. Anthropogenic inputs of nutrients …
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Interannual variability of air-sea fluxes of carbon dioxide and oxygen
The currently observed increase in atmospheric CO2 due anthropogenic emissions is substantially slowed by natural processes that incorporate CO2 into the terrestrial biota and the ocean. Year-to-year changes in the CO2 growth rate that exceed variations in the fossil fuel source indicate a …
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Exploring mechanisms for the decrease of atmospheric CO₂ during the last glacial maximum using a four-box ocean model
… dioxide for the last 400,000 years revealed that atmospheric CO2 decreased from a pre-industrial concentration of 280 ppmV to approximately 200 ppmV during the last glacial maximum (Petit et al., 1999). Several hypotheses as to why this happened have been suggested yet no one explanation has been …
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Spatiotemporal Variability of CO2, Solar-Induced Fluorescence, And Precipitation Over the Tropical Rainforests
… the dry/fire season, transitioning from an atmospheric CO2 sink to a CO2 source. The Amazon basin, Congo basin, and the tropical Indo-Pacific play vital roles in biospheric processes, which contribute to Earth’s atmospheric CO2 concentration. This investigation will use various space-based …
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Oxygen isotopes as a tracer of biospheric CO2 gross fluxes : a local feasibility study
Quantitative knowledge of gross biospheric CO2 fluxes is crucial in atmospheric carbon cycle budgeting, especially in view of unknown biospheric feedback mechanisms to an increasing atmospheric CO2 mixing ratio or to temperature changes. The 18O/16O ratio of CO2 has the potential to separate …
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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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Sustainability implications of carbon delivery in microalgae cultivation for the production of biofuel
… most microalgae. Moreover, using microalgae for atmospheric CO2 mitigation to combat climate change is promising, as waste sources and atmospheric CO2 can be utilized to produce useful products. The challenge is developing technologies, processes, and strategies that utilize carbon effectively …
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The influence of the evolution of anatomical characters on leaf hydraulic capacity
… have contributed to the evolution of plants. CO2 is one environmental factor that affects plants, and changes in CO2 concentration ([CO2]) in the atmosphere across geological time have been thought to have driven evolutionary changes in plant leaf anatomy, enabling plant leaves to adapt to …
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Effect of future CO2 and temperature regimes on phytoplankton community composition, biomass and photosynthetic rates in the western English Channel
CO2 storage in the oceans is strongly affected by biological processes. Production of organic matter through phytoplankton photosynthesis drives CO2 sequestration, which feeds back to atmospheric CO2 and global climate. The ongoing increase in atmospheric CO2 and temperature is strongly associated …
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