|
|
Changes in runoff from selected glaciated catchments in the Alps
Chytil, Jan ; Jeníček, Michal (advisor) ; Nedělčev, Ondřej (referee)
Glaciers are crucial in alpine regions, especially during the summer months when they supply water to lower-lying regions. However, they are expected to melt more rapidly in the future and glacier water is expected to decline gradually. As a consequence, the seasonality of runoff from glacial catchments will change and the water deficit in the summer months will intensify. The goals of this thesis were (1) to assess the current state of knowledge on the hydrological regime of mountain glacier catchments and its changes, and (2) to evaluate the hydrological regimes of selected mountain glacier catchments in the Alps. Long time series from 5 glacier catchments in the Swiss Alps were used to find trends in monthly runoff. Trends were calculated using the Mann-Kendall trend test and quantified by the Sen's slope estimator. In general, the results indicated that summer flows increased the most in the catchments with the highest percentage of glaciation and also with the highest mean elevation. A decreasing trend in summer flows and an increasing trend in winter flows occurred at stations with low percent glaciation and large catchments area. Catchments with both low percent glaciation and the lowest average elevation were the least subject to trends in both average and extreme flows. Accelerating...
|
|
|
Effect of global climate change on areal and phenology shifts of dragoflies species
Perthen, Ervín ; Černý, Martin (advisor) ; Bílková, Eva (referee)
Climate change in recent decades affects the distribution and phenology of dragonflies. The main factor causing these changes is the increase in the average global temperature, but other factors, such as loss of habitats or changes in precipitation regime, also play a role. As a result of climate change, phenological processes are accelerating. We can therefore observe a faster egg development rates, an earlier emergence of adults, a longer flight period and also a shift in voltinism towards a greater number of generations per year. Good dispersal abilities allow dragonflies to respond to changing environmental conditions also by shifting their distribution. The ranges of most species are currently expanding towards the poles. Generalists and species capable of using temporary waters expand their ranges the most, while specialized species with a narrow niche are the most threatened by climate change. Shifts are also visible in the altitudinal distribution, increasing temperatures allow warm- adapted species to expand their ranges to higher altitudes. Keywords: climate change, dragonflies, distribution, phenology, temperature, altitudinal shift
|
|
|
Food webs of glacier-fed streams.
Komárková, Julie ; Kopalová, Kateřina (advisor) ; Fuksa, Josef (referee)
This work focuses on glacier-fed stream ecosystems, with the centre of attention being on the community composition and characterization of their food web structure. Glacier-fed streams are harsh environments in terms of their physicochemical characteristics. These streams exhibit low temperatures and specific flow regimes, with the peak of meltwater generation, and thus discharge, in the summer. In turn, streamwater nutrient concentrations, light availability, and turbidity all vary seasonally according to the flow regime. Compositionally, glacier-fed stream habitats host chemolithotrophic bacteria along with photoautotrophic producers, such as diatoms, Chrysophyceae, and Cyanobacteria, which together serve at the bottom of food webs as primary producers. These streams also host some fungal taxa, that together with heterotrophic bacteria, represent the primary decomposers. Macroinvertebrates, including the water larvae of species Diamesa and Pseudodiamesa, or from the Ephemeroptera or Plecoptera groups, are important secondary producers with high feeding plasticity; that is, they are mainly grazing biofilm or collecting/filtering organic matter, with the possibility of predation. Other than that, in glacier-fed streams, there is usually no presence of higher trophic levels with large- bodied...
|
|
|
Evaluation of environmental impacts of selected crops growing by LCA method
NNANDO, Emeka Micheal
Abstract The consequences of agricultural intensification and conventional farming are becoming increasingly apparent as climate change and variability continue to worsen. This study evaluated the environmental impacts of soybean production, with a focus on the climate change impact category. Agricultural data for various inputs, agrotechnical operations, and outputs of the production process were systematically collected from three distinct soybean farms (Becicka, Michalec and Agrokiwi) in the Pardubice district of the Czech Republic and analyzed using the Life Cycle Assessment (LCA) framework. The functional unit considered in this study was 1 kg of soybeans. The results of the LCA show that the Agrokiwi and Michalec farms make the largest and smallest contributions to the climate change impact category with 6.17 kg CO2eq and 2.1 kg CO2eq respectively. The highest contribution, 51 percent, from Agrokiwi was attributed to the application of NPK fertilizer (15-15-15) and tillage plowing of the fields, with 0.0506 kg CO2eq and 0.0237 kg CO2eq respectively, while sowing and transport contributed the least, with 0.00979 kg CO2eq and 0.0091 kg CO2eq respectively. Findings also revealed a relationship between inputs, agrotechnical operations in soybean production, and their contribution to climate change.Regarding climate smartness or environmental sustainability, the Michalec agricultural practices/production system is more environmentally friendly due to the low use of mineral fertilizers and the spreading method. The results of the study suggest that the environmental performance of soybean production could be significantly improved by switching from synthetic fertilizers to more environmentally friendly organic farming, introducing crop rotations, and using disease-resistant seed varieties as a means of implementing sustainable agricultural practices/systems.
|
|
|
Study of the cooling system of a building with regard to climate change in the Czech Republic
Vašulka, Tomáš ; Charvát, Pavel (referee) ; Fišer, Jan (advisor)
The diploma thesis aims to prepare a study of the cooling system of a multifunctional building with regard to climate change predicted until the middle of the 21st century. The work includes determining the heat load of refrigerated rooms and designing measures to reduce heat gains in the summer. Diploma thesis includes design of a cooling system with fan-coil units as end appliances with the necessary hydraulic calculations. A single-stage absorption cooling unit is used as the considered cooling source, to which a free cooling heat exchanger is assigned. The design of the cooling source includes the necessary hydraulic calculations and dimensioning of the system ensuring its functional operation. Part of the diploma thesis is drawing documentation of cooling technology and connection of fan-coil units.
|
|
|
Effects of nitrogen supply and drought on wheat grain quality under the ambient and elevated concentrations of carbon dioxide
Moravcová, Gabriela ; Vránová, Dana (referee) ; Hrstka, Miroslav (advisor)
This diploma thesis deals with effects of nitrogen supply, drought and UV radiation on wheat grain quality under the ambient and elevated concentrations of carbon dioxide. The theoretical part deals with the global climate changes, greenhouse gases and especially with effects of elevated concentrations of carbon dioxide on plants. Also, it is dealt with effects of elevated concentrations of carbon dioxide on the wheat grain quality. In the experimental part nitrogen content by the Kjeldahl method, contents of dry and wet gluten, Zeleny test, falling number and content of starch in the wheat samples were determined. The results of this study confirmed affecting the quality of the wheat grain from the elevated concentrations of CO2, nitrogen fertilization, drought and UV radiation. The most evident was the influence of nitrogen nutrition, fertilization positively affected the quality of grain, there was an increase in content of crude protein, gluten content, value of Zeleny sedimentation test, and falling number. As a result of the increase in protein content was also a decrease in starch content. Due to increased levels of carbon dioxide protein content and gluten, Zeleny sedimentation test values and falling number decreased and conversely starch content increased. The decrease of Zeleny sedimentation test by the influence of elevated CO2 concentration was fully compensated by nitrogen fertilization.
|
|
|
Climatological analysis of the Thaya river basin
Macík, Ondřej ; Kněžínková, Barbora (referee) ; Marton, Daniel (advisor)
The current climate changes and the persistent drought raise questions about the future development of temperatures and precipitation in the Czech Republic. One of the most affected area is south Moravia and the basin of River Dyje located there. The iam of this bachelor's thesis is to predict the future development of climate in the basin of River Dyje, using emission scenarios, a global climate model and an artifical time series Baseline by using a stochastic generator LARS-WG and subsequent analysis of the results. The obtained results will be suitably compared with each other and adjusted to the form for their future use.
|
|
| |
|
|
Extreme hydrological events in the context of urban planning
Klimeš, Zdeněk ; Dráb, Aleš (referee) ; Duchan, David (advisor)
The purpose of the bachelor thesis was to describe known extreme hydrological events and potential attitudes to minimalize their negative impacts. The thesis was written as literature recherche from different points of view, not only from a one-sided technical or ecological point. It proceeds systematically from describing the historical evolution of the subject matter through the presentation of global ecological problems, outlining the legislative background and the findings from specialised literature, to the examples of current trends. In view of the fact that the issue is so broad, the thesis treats only certain parts in detail. The subject of interest is the demonstration of separate measures against floods and droughts and the effects of their synergy concerning the minimalization of the repercussions of extreme hydrological events.
|
|
|
Rainfall runoff process in time of climate change
Benáčková, Kateřina ; Janál,, Petr (referee) ; Marton, Daniel (advisor)
The aim of The Diploma Thesis was to compile a conceptual rainfall-runoff model, that would be eligible to model discharge in conditions of climate changes. After thorough verifications of possible variants, user program Runoff Prophet that is eligible to simulate discharge in closing profile of any river basin was compiled within this paper. Runoff Prophet is deterministic lumped model with monthly computation time step and from the hydrologic phenomena it takes soil moisture, evapotranspiration, groundwater flow and the watercourse flow into account. Its calibration is based on the differential evolution principle with Nash–Sutcliffe model efficiency coefficient as the calibration criterion. Developed software was tested on Vír I. catchment basin and the results of this probe were evaluated from viewpoints of air temperature, precipitation and discharge characteristics in the Dalečín measurement river cross section in distant future according to A1B SRES climate scenario, implemented in LARS-WG weather generator.
|
guest ::
