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Shale gas extraction
Podhorský, Jakub ; Brázdil, Marian (referee) ; Šnajdárek, Ladislav (advisor)
This bachelor’s thesis on Shale gas extraction describes extraction and world shale gas resources. At the beginning it provides introduction to the terms of geology and overview of historical evolution of extraction and crucial technologies that are currently used in extraction. Shale gas exploration and extraction development is briefly mentioned. Horizontal drilling and hydraulic fracturing is then further described and also summary of the equipment is provided. Potential environmental risks associated with extraction or hydraulic fracturing itself are described. Subsequently world shale gas resources and potential extraction places are described. World technically recoverable resources are estimated at 7245 Tcf. Shale gas commercial production is currently underway in the United States, Canada and China.
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Role of plants in the greenhouse gas budget of a sedge fen
NOVOTNÁ, Jitka
Wetlands play an important role in the global carbon cycle because they fix or release carbon dioxide (CO2) and are a source of atmospheric methane (CH4). The dynamics of the exchange of these greenhouse gases is determined mainly by the height and dynamics of water level, temperature and vegetation structure and biomass. The aim of this study was to evaluate the effect of plants with a dominant sedge, Carex acuta, on CO2 and CH4 emissions from a sedge fen on a model site ?The Wet Meadows? near Třeboň. This study included field research using a method of manual emission chambers in order to monitor the differences in the emissions between hummocks with vegetation and hollows without vegetation. In addition, aboveground plant biomass, water level and temperature were followed. The field research was supplemented with a mesocosm experiment in which the influence of water regime on C. acuta biomass production was evaluated. The results of the field research show that water level had a significant effect on CO2 emissions only in the hollows. Soil temperature was an important factor on both micro-sites. The presence and biomass of the plants had a substantial effect on the amounts of CO2 emissions, but only in the second part of the vegetation season, when the plant aboveground biomass reached its seasonal maximum. CH4 emissions were significantly influenced by the water level and its previous dynamics but not by temperature. An important factor was also the presence of sedge hummocks, which vented considerable amounts of CH4 into the atmosphere when their basal parts were flooded. Fairly small amounts of CH4 were mediated by the plants at water levels between -20 cm and the soil surface. A conceptual model has been created for the conditions of 2014 in order to estimate the effect of the C. acuta dominated vegetation of the hummocks on carbon emissions and its balance. The carbon assimilation into plant biomass exceeded not only the carbon emissions mediated by the plants, but also the emissions from the whole hummocks. Approximately 130 g C m-2 per vegetation season was stored into the soil owing to the plants. The mesocosm experiment indicated that the plants of C. acuta formed the greatest belowground biomass as well as total biomass in the limosal ecophase followed by the plants subjected to a spring flood.
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Shale gas extraction
Podhorský, Jakub ; Brázdil, Marian (referee) ; Šnajdárek, Ladislav (advisor)
This bachelor’s thesis on Shale gas extraction describes extraction and world shale gas resources. At the beginning it provides introduction to the terms of geology and overview of historical evolution of extraction and crucial technologies that are currently used in extraction. Shale gas exploration and extraction development is briefly mentioned. Horizontal drilling and hydraulic fracturing is then further described and also summary of the equipment is provided. Potential environmental risks associated with extraction or hydraulic fracturing itself are described. Subsequently world shale gas resources and potential extraction places are described. World technically recoverable resources are estimated at 7245 Tcf. Shale gas commercial production is currently underway in the United States, Canada and China.
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