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 41 for “"CO2 fluxes"”.
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Assessing landscape and seasonal controls on CO2 fluxes in a karst sinkhole
… can serve as carbon sinks when carbon dioxide (CO2) reacts with water to form carbonic acid, which then weathers carbonate rocks. However, CO2 can also move through the subsurface via gas diffusion, a process that is not well-understood in karst systems. This study focused on quantifying CO2 …
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Investigation of high nighttime CO2-fluxes at the Wetzstein spruce forest site in Thuringia, Germany
Nighttime fluxes of CO2 are uncommonly high at the Wetzstein spruce site, in Thuringia, Germany (Anthoni et al., 2004). As a result, the annual sums of CO2- flux obtained for this site are not comparable with the ones obtained at similar spruce ecosystems (Rebmann, 2004; Grünwald and Bernhofer, …
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Non-growing season CO2 fluxes of a boreal fen – key drivers and responses to anomalous winter conditions
Non-growing season carbon fluxes can contribute to a significant amount of the full-year ecosystem carbon balance. Year-round net ecosystem exchange (NEE) data from 17 years was used to analyse the non-growing season carbon dioxide (CO2) fluxes together with environmental and meteorological …
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Decomposition of Urban CO2 Fluxes into Fossil and Biogenic Components using a novel Relaxed Eddy Accumulation System
… accumulation (REA) system for collection of 14CO2 air samples and its first application in the city of Zurich, Switzerland. The REA system, developed within the ICOS (Integrated Carbon Observation System) Cities project, selects air based on a 20 Hz vertical wind signal into an upwind and a …
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A Comparison of Gas Exchange Models in the Estimation of CO2 Fluxes in the South Atlantic South of Africa for the Summer Season of 2008/2009
… is a problem in the determination of air-sea CO2 fluxes because of the number of different relationships used in calculating gas transfer velocities. There is also a problem with the CO2 sink in the Southern Ocean being greatly underestimated. Data were collected underway using an autonomous …
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A comparison of gas exchange models in the estimation of CO2 fluxes in the South Atlantic South of Africa for the summer season of 2008/2009
… is a problem in the determination of air-sea CO2 fluxes because of the number of different relationships used in calculating gas transfer velocities. There is also a problem with the CO2 sink in the Southern Ocean being greatly underestimated. Data were collected underway using an autonomous …
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Heat transfer, evaporation and carbon dioxide transfer in soil
… Soil water evaporation and soil carbon dioxide (CO2) fluxes both involve soil gas transport processes and properties, and both impact the soil environment and physical, chemical, and biological processes occurring in the soil. Accurate and dynamic measurements of soil water evaporation and soil …
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Wood and soil-atmosphere carbon dioxide fluxes from a tropical forest ecosystem
… of controlling mechanisms and magnitude of CO2 sources from tropical forests will improve our ability to predict future impacts of climate changes. The research presented in this dissertation has focused on determining the magnitude and characteristics of the CO2 flux from tropical wood and …
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Carbon fluxes at an upland blanket bog in the north Pennines
… were made of all of the key gaseous carbon fluxes, including the net CO2 flux, the soil CO2 flux and emissions as methane. A flux partitioning model was utilised to separate the net CO2 flux into its component parts. Values for the fluvial carbon losses from the site were taken from the …
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Spatio-temporal Variability in Surface Ocean pCO2 Inferred from Observations
The variability of surface ocean pCO2 is examined on multiple spatial and temporal scales. Temporal autocorrelation analysis is used to examine pCO2 variability over multiple years. Spatial autocorrelation analysis describes pCO2 variability over multiple spatial scales. Spatial autocorrelation …
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Soil-atmosphere fluxes of CO2 and CH4 in annual and perennial cropping systems in southern Sweden
… This study set out to compare soil-atmosphere fluxes of CO2 and CH4 from annual and perennial cropping systems at a study site in southern Sweden. The site comprised two adjacent fields, one growing the perennial grain intermediate wheatgrass, the other following an annual crop rotation. Using …
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Physical and biological forcings on the carbonate chemistry in the North Atlantic Ocean
The atmospheric concentration of CO2 has risen considerably since the industrial revolution, and the subsequent uptake of atmospheric CO2 by the oceans has affected the carbonate system and caused a reduction in the pH of the oceans. Model estimates involving future CO2 emission scenarios have …
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Investigation of horizontal meteorological structures in comparison to turbulent structures at a forest edge
… is largest in the terrestrial biospheres (CO2 sink). Despite a vast number of ecological studies about forest ecosystem, there are still outstanding issues about prevailing meteorological conditions, turbulent and coherent structures and exchange processes of heterogeneous forest …
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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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Correlation Analyses among Soil, Plant, and Environmental Variables and Greenhouse Gas Emissions from Furrow-irrigated Rice on a Silt-loam Soil
… (CH4), nitrous oxide (N2O), and carbon dioxide (CO2) fluxes and emissions and global warming potential (GWP) and near-surface soil properties and environmental factors over two growing seasons (2018 and 2019) under furrow-irrigated rice on a silt-loam soil in eastern Arkansas. Gas samples were …
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Carbon dynamics under natural and manipulated meteorological boundary conditions in a forest and a fen ecosystem
… of extreme meteorological boundary conditions on CO2 fluxes in two ecosystems in South-eastern Germany. Using a combination of field site manipulation and laboratory experiments we investigated the effects of prolonged summer drought and soil frost on soil C dynamics in a Norway spruce forest. In …
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Desarrollo y aplicaciones de un simulador de mezcla dinámica para el estudio de la reactividad química en estuarios
… salinity gradients has been studied (quantifying CO2 fluxes water-atmosphere). Tidal variations at CO2 fluxes also were registered. By other hand, nutrient reactivity has been characterised, putting special attention in the laboratory verification of apatite formation from dissolved inorganic …
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Long-term Impacts of Annual Cattle Manure and Fertilizer on Soil Quality Under Corn-Soybean Rotation in Eastern South Dakota
… soil hydrological properties in 2015. Soil GHG fluxes were observed once a week from June 2015 through October 2015 and May 2016 to August 2016 depending on the climatic conditions. Results showed that manure maintained the soil pH for 0-10 cm depth and inorganic fertilizer decreased it compared …
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The Effect of Prescribed Burning on Soil Microbial Communities, Nutrients, and Carbon Dioxide Fluxes Under and Between Sagebrush Canopies in the Semi-Arid Rangelands of Northern Nevada
… nutrient dynamics, and carbon dioxide (CO2) fluxes. These changes can have direct and indirect effects on soil biochemistry and respiration. The effects of fire on soil largely depend on time and seasonality, frequency, severity, and management practices pre-and-post burning. The …
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Fire and herbivory effects on soil organic carbon stocks and soil greenhouse gas emissions from South African grasslands and savannas: Implications for global change
… principal soil greenhouse gases, carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). We however, have limited understanding of how wildlife herbivory, fire and pyric-herbivory influence SOC stocks and soil greenhouse gas emissions in these ecosystems. We hypothesised that, in low nutrient …
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