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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 26 for “"CO2 efflux"”.
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Relationships Among Soil Properties and Soil CO2 Efflux in a Loblolly Pine-Switchgrass Intercropped System
The components of soil CO2 efflux are affected by many soil properties including temperature, moisture, microbial abundance and activity, and other soil physical and chemical properties. Changes in these factors can result in high spatial and temporal variability of total soil CO2 efflux. Low …
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Environmental And Stand Variables Influencing Soil CO2 Efflux Across The Managed Range Of Loblolly Pine
… of carbon from the soil in the form of soil CO2 efflux (Rs) and a component of that total efflux, heterotrophic respiration index (Rh), from data collected across the managed range of loblolly pine in the Southeastern U.S. We also performed tests of significance on controlled subsets of these …
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Soil Co2 Efflux and Soil Carbon Content as Influenced by Thinning in Loblolly Pine Plantations on the Piedmont of Virginia
… to determine significant drivers in soil CO2 efflux. Temperature proved to be the most significant driver of soil respiration, with a positive correlation in thinned and unthinned stands. When modeled using regression, thinning was a significant variable for predicting soil respiration (p …
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The Short-term Effects of Fertilization on Total Soil CO2 Efflux, Heterotrophic, and Autotrophic Respiration of Loblolly Pine (Pinus taeda L.)
… the below-ground processes that drive soil CO2 efflux in loblolly pine (Pinus taeda L.). A thorough understanding of below-ground carbon dynamics is necessary for the estimation of net ecosystem productivity and the carbon storage potential of these managed systems. In April 2004, we began …
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Winter Carbon Dioxide Efflux in Sierra Nevada Meadows: Contributions to Annual Carbon Budgets, Influence of Snowpack, and Subnivean Conditions
… and can display high levels of carbon dioxide (CO2) efflux during the growing season. Yet wintertime instantaneous CO2 efflux rates from these systems, along with further understanding of what ecological mechanisms are affecting CO2 efflux remains poorly constrained due to limited site access …
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Quantification and Physiology of Carbon Dynamics in Intensively Managed Loblolly Pine (Pinus taeda L.)
… soil C, root, and stand influences on soil CO2 efflux on the South Carolina coastal plain and (2) quantifying soil CO2 efflux over a rotation in loblolly pine stands located on the South Carolina coastal plain and the Virginia piedmont. In relation to the first objective, temporal variation …
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Dynamic interactions between CO2 efflu, sap flow and internal CO2 concentration in tree stems: implications towards the assessment of actual stem respiration
… order to verify whether forests are net sinks of CO2, it is necessary to accurately quantify the photosynthesis (CO2 uptake) and respiration (CO2 release) by trees. The objective of the Ph.D. was to perform fundamental research on dynamics in respiration of tree stems. It became clear that …
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Soil Carbon Dioxide Efflux in a Naturally Regenerated and a Planted Clear-Cut on the Virginia Piedmont
… role in mitigating increasing atmospheric CO2 through their capacity to store carbon. In this regard, it is important to evaluate the implications of forest management on changes in carbon cycling and sequestration and to determine the magnitude by which the efflux of CO2 from the soil …
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The influence of leaf litter and plants on soil respiration before, during and after a severe drought
… have undergone drought produce a large pulse of CO2 when rewet; a phenomenon known as the 'Birch effect'. I conducted lab incubations and a greenhouse experiment with poplar saplings to quantify soil carbon release during and after drought. I measured soil respiration to investigate potential …
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Corticular Photosynthetic Dynamics for a Coastal Evergreen Shrub: Myrica Cerifera
… plant carbon gain by reducing respirational CO2 loss. Maximum % refixation was 110 ± 39 % of CO2 efflux in the dark (Rd) in 1st order branches during winter, minimum was 18 ± 3 % in 5th order branches during summer. Variations in % refixation paralleled changes in photosynthetically active …
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Dynamics and Drivers: Carbon fluxes from temperate freshwater reservoirs
… sources of methane (CH4) and carbon dioxide (CO2) in the global carbon cycle, influencing the earth’s atmospheric energy budget. When considering freshwater reservoirs, these greenhouse gas emissions are anthropogenic, yet have received little research focus or integration into carbon budgets, …
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Soil respiration, microbial respiration and mineralisation in soils of montane rainforests of Southern Ecuador: influence of altitude
… years, the contribution of roots to total soil CO2 efflux over one year. Soils of the study sites were sampled twice and biochemical and microbial parameters were determined.
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Tree functional diversity affects litter decomposition and arthropod community composition in a tropical forest
… the litter and measured litter chemistry, soil CO2 efflux, and litter mass loss. I found that decomposition in mesocosms was similar to that measured with the conventional litterbag method and consequently, mesocosms are an effective method to measure litter decomposition and soil respiration in …
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Long-Term (24-Year) Effects of Harvest Disturbances on Ecosystem Productivity and Carbon Sequestration in Tupelo-Cypress Swamps in the Mobile-Tensaw River Delta
… belowground woody debris, soil C, and soil CO2 efflux were measured. Twenty-four years after treatments were applied, forest C levels were higher in SKID treatments (206.1 Mg C ha-1) than in HELI treatments (168.7 Mg C ha-1). GLYPH treatments are holding less (144.2 Mg C ha-1) while REF …
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Impacts of mountain pine beetle outbreak on biogeochemical cycling in a high elevation whitebark pine ecosystem
… initial stages of WbP attack were subtle. Soil CO2 efflux rates were generally higher under unattacked trees, but overall, the similarities were more apparent than the differences. My results indicate that while beetle attack drives a large pulse of C and N canopy to the forest floor after …
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Impacts of mountain pine beetle outbreak on biogeochemical cycling in a high elevation whitebark pine ecosystem
… initial stages of WbP attack were subtle. Soil CO2 efflux rates were generally higher under unattacked trees, but overall, the similarities were more apparent than the differences. My results indicate that while beetle attack drives a large pulse of C and N canopy to the forest floor after …
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Tree Growth and Carbon Balance in a Temperate Forest Exposed to Elevated Carbon Dioxide for Eight Years
… 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 investigates …
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The Influence of Selection Silviculture Biomass Harvesting on Soil Carbon, Nutrients, and Respiration in a Northern Mixed-Deciduous Forest
… increased nitrification, and reduced soil CO2 efflux (FCO2) from compaction and root senescence. However, results are inconsistent; differences may be linked to insufficient investigation and characterisation of variability in forest structure, silvicultural methods, and intensity and …
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The effect of bush clearing on soil respiration in north-central Namibia: Cheetah conservation fund and Erichsfelde
… processes, such as the carbon cycle and soil CO2 efflux has not yet been quantified in Namibia. The main aim of this study was to determine and compare the amount of soil respiration between the cleared and uncleared sites at different seasons and also to determine the effect of soil …
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Forest respiration from eddy covariance and chamber measurements under high turbulence and a bark beetle epidemic
… developed from periodic foliage, wood and soil CO2 efflux measurements fit to models of phenological seasonal change and diurnal temperature response. These models estimated ecosystem mean nightly respiration to have declined 32% after the bark beetle epidemic (7.0 ±0.22 μmol m-2 s-1 in 2005 to …
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