|
|
Photosynthetic activity of phytoplankton in eutrophic waters
TESAŘOVÁ, Blanka
Photosynthesis was measured in several natural populations and cultivated strains of cyanobacteria. In the natural fishpond phytoplankton species of the Microcystis genus and small {$\mu$}-cyanobakteria were dominated. Anabaena mendotae and Anabaena lemmermannii, different cultivated strains were selected for photosynthesis measurements. Photosynthesis was estimated as an oxygen evolution in Illuminova (Sweden AB) light pippeting system. During the experiment the oxygen concentration, temperature and photon flux density were detected automatically and registered in computer. Results were evaluated as Photosynthesis-Irradiance (P-I) response curves. Altogether 13 experiments were performed. In the natural cyanobacterial populations as well as in the cultivated strains the results confirmed high efficiency of photosynthesis in low irradiances. In some natural waterbloom-forming populations of Microcystis the results demonstrated also the high photosynthetic performace in high irradiances. It is evident that these cyanobacteria are able to avoid damage to the photosynthetic apparatus in photooxidative conditions. These findings probably reflect the mechanism by which cyanobacteria outcompete chlorococcal algae in the shallow eutrophic water bodies.
|
|
|
Processes in the forest vegetation of thermophyticum in the past decades
Pospíšková, Marie ; Hédl, Radim (advisor) ; Szabó, Péter (referee)
The thermophilous forests, especially their herb layer, are important from the conservational as well as from the cultural point of view because they represent unique communities directly and indirectly affected by man on the long term basis. Since the 19th century the way these communities are affected changed significantly, the same way as the whole society changed, and the vegetation responded by shift of species composition, diversity and also changes of the spatial structure. This thesis brings together the most relevant changes of vegetation and their causes. However, there is similar situation in the whole Europe, or more widely in the whole temperate zone, thus there are references also for other countries. Regarding historical ecology, one of the most studied countries is the Great Britain, which is mentioned the most often in this work.
|
|
|
Lichens and eutrophication
Jadrná, Iva ; Svoboda, David (advisor) ; Malíček, Jiří (referee)
Eutrophication is a process of organic nutrients enrichment in an ecosystem, especially nitrogen and phosphorus. This bachelor thesis is dealing with the influence of eutrophication on lichens, especially with the effect of nitrogen compounds in the air and the effect of the combination of nitrogen compounds with phosphorus on epiphytic lichens. Eutrophication is defined and information is provided on changes in abundance and diversity of lichen cover. The mechanisms of eutrophication tolerance in lichens are also described. Key words: lichens, epiphytes, eutrophication, ammonia, ammonium ions, nitrogen oxides, phosphorus
|
|
|
Forest vegetation changes in the Bohemian Forest during the second half of 20th century
Prach, Jindřich ; Kopecký, Martin (advisor) ; Sádlo, Jiří (referee)
Long-term forest vegetation changes were studied in the Bohemian Forest and its foothills. New vegetation relevés were taken at sites of typological plots established by forest engineers between 1955 and 1980. Data from 158 semi-permanent plots were analysed using modern statistical methods. The data show significant changes and homogenization of the vegetation. Ellenberg indicator values indicate eutrofication. Repeated measurements of soil pH suggest acidification, but the interpretation of these data is complicated by methodological problems. The forests under study exhibit high spatial variability. No main prevailing trend in vegetation changes was found. The changes are considered to be related to sulphur and nitrogen deposition and forest management. The influence of increasing age of forest stands seems to be unimportant. Discussed are not only vegetation changes and their possible causes but also the possibilities and limitations of using such old forestry data in botanical and ecological studies.
|
|
|
Management of the protected areas in sand habitats
Šímová, Kamila ; Münzbergová, Zuzana (advisor) ; Pivnička, Karel (referee)
Management of the protected areas in sand habitats is a thesis interested in the management techniques in relation to the sand habitats. In Central Europe, sand habitats are a rare and threatened grassland biotope. In the Czech Republic, we can find natural sand habitats localities, which are threatened by the human impact and anthropogenic localities, which tend to increase in number. Diversity and richness of the natural stands is gradually decreasing due to the high sensitivity of the species to any change of the local environment. These changes are mainly caused by the human activity. The negative effects are eutrophication, acidification and accelerated succession. The management of the sand habitats should contain many succession regulation tools and techniques reducing eutrophication. I discuss mowing, removal of the expansive plant species, pasturage, burning and sod disturbance or sod cutting. Each of these methods has specific impacts on the ecosystems and the best management combines them to achieve the best performance of the protected area. The most preferable method seems to be sod cutting, due to its high effectivity. However, there are many questions about sod cutting that need to be answered in a future study, such as how the population dynamics after sod cutting will look like, what the...
|
|
|
Forest vegetation in Eastern Elbe Basin in the mid-20th century and today
Pospíšková, Marie ; Hédl, Radim (advisor) ; Novák, Jan (referee)
This thesis describes the shift in vegetation of broadleaf forests in eastern part of the Elbe River Basin between 1958-1968 and 2011-2013. It emphasizes the understorey vegetation. From lowland woodlands in other temperate regions in Europe and North America changes towards eutrophic and mesophytic vegetation are documented, specifically driven by changes in forest management and by atmospheric depositions; in some localities the game impact can be also important. The data were obtained by sampling 190 typological semi-permanent plots, which were precisely located - in 43% the original soil pit was found. The vegetation on study sites shifted towards nutrient-demanding, shade- adapted species, it was partly ruderalized. These changes can be seen on the level of species and communities as well as on phytosociological level. Increase of soil pH and moisture was discovered using Ellenberg indicator values. The number of seedlings and cover of shrubs also increased significantly. Homogenization of sites was significant as well although total number of species and alpha- diversity remained unchanged. These changes are probably caused by changes in forest management and by atmospheric depositions of nitrogen. On subset of plots in game-preserves the vegetation also demonstrated eutrophication but no increase in...
|
|
|
Changes in epiphytic lichen biota in the Czech Republic with emphasis on current situation
Hronová, Nikola ; Malíček, Jiří (advisor) ; Palice, Zdeněk (referee)
During the last two centuries a significant change of lichen communities has happened in the Czech Republic. Important factors which had influencing the lichen biota in the past and recently are summarized in this bachelor thesis. Acid rain caused by high imissions of SO2 a NOx was the most important factors of change of species and remaining acidification of substrates is still influencing lichen communities. Until the end of 80's of 20th century acid rain was a dominant factor influencing lichens. Afterwards, thanks to drop of its intensity in 90's of 20th eutrophication and availability of nitrogen in landscape became dominant influencing factors. All these factors mainly affected the communities of macrolichens, and especially cyanolichens to such an extent that some species in the Czech Republic became extinct. Recently the increasing availability of nutrients has been supporting the spread of nitrophilous species. Due to decrease of SO2 emissions to values from the end of 19th century some areas have been recolonized and some endangered species have returned. The transformation of lichen communities has also been significantly affected by forest management and land use. Based on changing climate and change of natural habitats a further decline mainly of suboceanic species is expected. A more...
|
|
|
Problematika likvidace sinic na vybrané vodní nádrži
Drápalová, Jitka
This bachelor thesis deals with the issues of eutrophication, specifically the extermination of cyanobacteria inside of a selected water tank. This work is divided into several parts. The first part engages in water pollution caused by phosphorus, phytoplankton, eutrophication and by methods and technologies restricting the presence of a water plant. The second part of this thesis includes characteristics of the area of our interest, which is the Brno Reservoir, as well as photo documentation. The last part describes in detail the whole project, which was implemented at the Brno Reservoir to suppress the mass reproduction of cyanobacteria. Values that have been measured in 2016 are also present in this chapter. The effectiveness of preventive measures that are currently employed at the Brno Reservoir has been evaluated using these values. Other options that might help to prevent cyanobacteria from mass reproduction in the water tank are further analyzed in the discussion. Advantages and disadvantages of these options are also being discussed there.
|
|
|
Obsah biogenů (N, P) ve vodě a sedimentu vybraných rybníků
Kyselová, Martina
The thesis contains findings about ponds, their water and sediment. Further findings on the eutrophication of ponds and biogens N and P, which play the most important role in it. Part of the thesis is an experimental part for which samples of water and sediment from the Šumický horní, Zámecký, Bohuslavický I and Ráček I were taken in 2016. In the laboratory of the Department of Fisheries and Hydrobiology, the basic indicators for water quality assessment and the given indicator in Sediment were set. The results of the water analyses were compared with the requirements of Government Regulation No. 401/2015 Coll. On water quality. Based on the results of the sediment analysis, the possibility of their use in agriculture was assessed.
|
|
|
Eutrofizace povrchových vod
Kunze, David
This bachelor thesis deals with eutrophication of surface waters. People dramatically increase trophic conditions of water ecosystems. Attention is focused on phosphorus as a crucial nutrient for excessive growth of phytoplankton, especially cyanobacteria. Wastewaters are the main source of phosphorus. For this reason, wastewater treatment plants must use the best available techniques to eliminate phosphorus. Phosphorus will be a scarce resource. Author describes the possibilities for recycling of phosphorus. Measures to reduce eutrophication, including completed projects, are also mentioned. Nitrogen sources and the possibility of its removal, are discussed too. Measured concentrations of the basic indicators in representative profiles of river basins show the development of eutrophication in the Czech Republic. Finally, values of these indicators are compared with the limits set by current legislation.
|
guest ::
