Presented work consists of research and experimental part. Main focus of the research part is on mutual interaction between magnetic field and water and between magnetic field and cavitating flow. Prediction of the result is almost impossible, because the opinions on the effects differ, sometimes even go against each other. Experimental part consisted of three trials with permanent magnets. Electromagnetic probe was employed for measuring of the voltage. It appears, that magnetic field affects the cavitation, because in all of the trials the measured voltage changed after the switch from non-cavitating to cavitating flow. The change of the voltage was not great enough, thus application of this phenomenon in practice cannot be recommended.

This thesis deals with the numerical solution of cavitation bubble dynamics and with cyanobacteria gas vesicle behaviour. A program for the numerical calculation of bubble dynamics is created using the Rayleigh-Plesset equation and its modifications. Subsequently, bubbles of different sizes are investigated during acoustic cavitation with various driving frequencies. Furthermore, a model for hydrodynamic cavitation is created. The model combines CFD computation of flow in the Venturi nozzle with the cavitation bubble dynamics calculation. The last part of the work is dedicated to cyanobacteria gas vesicle behaviour in a variable pressure field and during passage through the Venturi nozzle.

This diploma thesis contains three parts. The first part is a background research which deals with notions such as cavitation and cyanobacteria. It also contains current phase in the use of cavitation. The second part deals with design, composition and constructional solution of hydraulic circuit on the riverboat. The third part deals with experimental certification of the cavitation effect on the cyanobacteria in the water. Design of the riverboat with the hydraulic circuit including the circuit itself and the cavitation tube was created in SolidWorks program, calculations, it’s processing and graphs were created in Microsoft Excel.

Carotenoids are natural pigments occurring in plants and many microorganisms, such as algae, yeast and bacteria. They represent the most common group of antioxidants with significant biological effect. Lipids are an essential component of all living organisms. They are the source and the reservoir of energy for organisms, which can also be used in the petrochemical industry for the production of biofuels. This thesis deals with the production properties of carotenoids and lipids by selected strains of yeasts, algae, and canobacteria, in order to apply the acquired knowledge and find cheap suitable alternatives for microbial biotechnological production of these metabolites using waste substrates. Carotenoids, coenzyme Q, and ergosterol in cells were determined by liquid chromatography. The lipid content and fatty acid profile was analyzed by gas chromatography. Cell morphology and localization of selected metabolites were analyzed by fluorescence lifetime imaging microscopy. In this work yeast genera Sporobolomyces, Cystofilobasidium and Rhodotorula were used. As the representatives of the algae and cyanobacteria strains of Desmodesmus, Cyanothece, Chlamydomonas, Synechoccocus and Chlorella strains were studied. In the overall comparison, the yeast strains were more productive than algae and cyanobacteria. The highest carotenoid production was found in S. pararoseus, C. capitatum and R. mucilaginosa cells, while the highest lipid yield was observed in strains of C. infirmominiatum and S. metaroseus.

The aim of the present master's thesis is to assess the problem of eutrophication in the reservoir named Hornoveská reservoir near the city of Fryšták. The main goal of this thesis is to do a search report on the topic of eutrophication of surface waters, to do practical measurement and make samples in the Hornoveská reservoir, and then evaluate results from these actions and determine the source of phosphorus in the reservoir. Last goal is to suggest actions which can improve the condition of reservoir by limitation the occurrence of algae and cyanobacteria in the summer period.

Introduction of the thesis deals with inquiry-based science learning - from the level of research to its evaluation. The following practical advice summarize information about the possibilities of obtaining natural material for teaching, creating permanent diatom preparations and examples of suitable determination literature for teachers. The main part of this work presents 12 elaborated study materials for research teaching method divided into five phycologically oriented topics: (1) cyanobacterial and algal physiology, (2) biodiversity of standing waters, (3) algae defense mechanisms, (4) cyanobacteria and algae like bioindicators, (5) substances in cyanobacteria and algae and their importance for humans. Individual study materials contain information on the level of research, methodological guidance for teachers with a theoretical basis and introductory questions to motivate students, as well as a recording sheet for students and, in conclusion, own proposed solution for teachers. Another part of this thesis is a comparison of inquiry-based science learning with frontal education, which is done by didactic test.

Nonphotochemical quenching and state transitions are an important photoprotective mechanism against excessive irradiation. In this work I studied changes in the size of the effective crosssection of photosystem II antennae in regard to the level of nonphotochemical quenching (state transitions) under different levels of light induced stress.

The master thesis lists the basic effects of nitrogen transformation in soil (nitrification), subsequent leaching of nitrates from soil to water and the effects of eutrophication of aquatic environment on the human health. The results of this experiment show that the interaction of all three factors (fertilization, soil moisture, vegetation) has a significant effect on the rate of nitrification. Generally, the nitrification rate increases with fertilization, decreases with presence of vegetation and decreases with soil moisture decrease. The health risk of nitrates in water consists in their consumption and the subsequent development of methemoglobinemia (especially in young infants) and the formation of N-nitroso compounds (e.g.nitrosamines), which have carcinogenic and teratogenic effects. Nitrate together with phosphates also promote the growth of cyanobacteria and algae. Cyanobacteria can produce cyanotoxins causing several groups of diseases.

The presented work was focused on the comparison between the production of selected metabolites by carotenogenic yeasts and microalgae cultivated under conditions of external stress. The main metabolites of interest were carotenoids, further lipophilic substances and lipids. Biotechnological overproduction of these metabolites could serve as a source of potentially beneficial substances not only for the pharmaceutical, cosmetic and food industries, but also for the production of third generation biofuels. Recently, there has been a growing interest in biofuels primarily from microalgae, which have a high potential in biofuel production and seem to be a promising source. The theoretical part deals with the description of individual genera of carotenogenic yeasts, microalgae, cyanobacteria, chemical composition of produced metabolites and brief biosynthesis. In addition, individual methods for analyzing the production of the metabolites of interest were described. The experimental part is focused on the comparison of production of carotenoids, coenzyme Q, ergosterols (phytosterols) and lipids by yeasts, microalgae and cyanobacteria. As a source of external stress, temperature, salt and light stress were chosen. The strains of Rhodotorula glutinis, Rhodotorula mucilaginosa, Sporidiobolus pararoseus and Cystofilobasidium macerans were studied from the yeast strains. Microalgae and cyanobacteria were Scenedesmus obliqus, Scenedesmus dimorphus, Chlorella sorokiniana, Chlorella saccharophila, Botryococcus brauni, Synechococcus nidulans and Arthrospira maxima. The yeast and algal strains were optimized for growth, carotenoid and lipid production. Applied salt stress showed a significant liquidation effect on algal and cyanobacterial strains. The thesis also monitored the biological stress, so-called co-cultivation of microalgae and yeasts. Further experiments will be the subject of future work.

In this diploma thesis, I deal with the influence of the sampling site on water quality in natural bathing lakes (Hostivar reservoir, Seberak pond and Vyzlovka pond) in this. I have established that hygienically significant kinds of phytoplankton may differ in terms of water quality especially where there are cyanobacteria constituting water bloom. Surface water bloom may be moved by wind to the lee side of the water body (Microcystis sp.). Aphanizomenon flos-aquae water bloom floating in water column can be affected by wind and by water flow (which may be partly affected by wind as well). With the prevailing fibrous Planktothrix agardhii which does not connstitute water bloom the concentration of chlorophyll-a and cyanobacterial cell abundance in individual sampling sites are similar although the concentration of chlorophyll-a a is about 200 g.l-1 . Microcystis sp. and Scenedesmus sp. survive under eutrophic conditions in competition. From the microbiological perspective, water quality can differ within a single sampling site in places at a distance of less than 100 m. Microbial contamination can be caused by bathers, water birds, farm animals and probably by the removing of microorganisms from sand, mud and sediments on the beach or shore. Rain episodes probably increase the abundance of E.coli...