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Fungal parasites as a factor affecting the dynamics of microalgal communities
Rosa, Jan ; Šťastný, Jan (advisor) ; Pichrtová, Martina (referee)
This bachelor thesis deals with fungal parasites which are an important factor that affects the dynamics of microalgal communities. Here I sum up the knowledge of parasites especially from Oomycota and Chytridiomycota along with a little focus on other groups. The basic characteristics of these fungal parasites, such as their host specificity and factors that affect their spreading ability between algal hosts, are summarized. The abiotic factors such as light and temperature, which are the most important factors causing epidemic, are mainly discussed. The fungal parasites can change the maximal population size and are able to alter the competitive relationships in microalgal communities. These factors are discussed in individual algal groups. The fungal parasites could be a negative economic player of the bioindustry and their future role in this industry is also discussed. Key words: parasite, host, host specificity, communities dynamics, algae, fungi, phytoplankton
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The diversity of filamentous freshwater algae and factors affecting the dynamics of their communities
Hadravová, Anna-Marie ; Šťastný, Jan (advisor) ; Woodard, Kateřina (referee)
This bachelors thesis is summing up the knowleadge from published papers which are dealing with the ecology of filamentous algae communities. It is focused on how the seasonal dynamics and biotic and abiotic factors do affect the communities of filamentous algae. The first part of the thesis contains a taxonomical overview of genera of the concern. In the second part there are different types of water habitats divided by their morphology and other characteristics (depth, temperature etc.). I am dealing with the factors affecting the composition of filamentous algae communities in stagnant waters of the temperate zone. No comprehensive works focusing on this field have been published so far. My thesis presents a synthesis of knowledge from avaliable sources. The species concepts of many filamentous algae are quite confusing, that is why their species determination is so difficult. That is the reason why there are not many journal articles dealing with such ecological issues. Key words: filamentous algae, ecology, freshwater habitats, diversity
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Ombrotrophy and minerotrophy of acidic wetlands - ecological and environmental indicators
Hanousková, Andrea ; Neustupa, Jiří (advisor) ; Šťastný, Jan (referee)
In this thesis I focus on different aspects of two basic types of peatlands - ombrotrophic bogs and minerotrophic fens, that differ in the source of their water supplies. In case of the bogs, all the moisture comes from precipitation, the fens are in varying degrees supplied with water from the mineral soil and bedrock. This concept is based on the assumption that hydrological conditions are essential for other properties of acidic wetlands, especially for vegetation, which is still the subject of discussion. Therefore I mention different gradients of peatlands (pH, nutrients and minerals) and important processes (succession, accumulation of peat) with regard to their relation to minerotrophy and ombrotrophy and I discuss their importance for the entire ecosystem. In the second part of my thesis, I focus on the algal assemblages in peatlands, which despite its immense diversity often form a neglected component of these ecosystems. The structure of algal communities vary in space and time under the influence of various factors, including, among others, ombrotrophy and minerotrophy. Powered by TCPDF (www.tcpdf.org)
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Diversity and ecology of filamentous green conjugate algae
Strouhalová, Pavla ; Šťastný, Jan (advisor) ; Pichrtová, Martina (referee)
Filamentous conjugating algae have a cosmopolitan distribution. They often inhabit fragile freshwater habitats such as temporary hydrated ditches or puddles of melting snow. Occurrence in this environment entails having to deal with extreme conditions. That helps them to variously adaptation and also the formation of resistant stages. Algae belonging to this group have an important role in nature, because they are often the first species that inhabit newly created habitats and consequently also often become the dominant species. Diversity, as well as the ecological requirements of individual representatives, is unclear. Taxonomy of filamentous algae is conjugating is most based on morphological characters that are not very reliable. For filamentous conjugating algae is polyploidy really frequent. With changeable ploidy relate also morphological variability and different environmental requirements.
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Diversity of the Micrasterias papillifera / M. radiosa (Desmidiales) species complex
Trumhová, Kateřina ; Šťastný, Jan (advisor) ; Mareš, Jan (referee)
This Master's thesis deals with diversity within the Micrasterias papillifera/ M. radiosa (Desmidiales) species complex. Both species are inhabitants of endangered biotops, like peat-bogs and, like other desmids, are used for biomonitoring. Many described varieties for both of them can be found in taxonomic literature, but their morphology is overlapping and revision of this species complex seemed to be necessary. All strains were isolated from peat-bogs and lakes across Europe and my dataset was properly completed by strains from algal collections. Results of phylogenetic analysis of sequences for ITS and psaA showed, that the real intraspecific diversity of Micrasterias papillifera Brébisson ex Ralfs was overestimated. Although I could find a little intraspecific diversity within the ‚papillifera' lineage in the phylogenetic tree based on ITS sequences, it did not correspond with a morphology of isolates. M. papillifera possess unexpected morphological plasticity and also some isolates designated as Micrasterias radiosa Ralfs were present in this lineage. On the contrary, there were only a few isolates in the lineage ‚radiosa'. This species seems to be relatively rare and probably has limited distribution. Both species are morphologically well delimited from each other on the basis of several characters...
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Diversity, distribution, phylogeny and ecology of the genus Micrasterias (Desmidiales)
Trumhová, Kateřina ; Šťastný, Jan (advisor) ; Bestová, Helena (referee)
The genus Micrasterias comprises one of the most beautiful organisms. It attracts, due to its spectacularly shaped cells, the attention of scientist and amateur biologist almost for almost 200 years. This thesis summarizes the current knowledge about these extraordinary organisms. The first part deals with the morphology and the life cycle of these algae. They share a unique type of reproduction (conjugation) with the other representatives of the class Zygnematophyceae. The second part concerns phylogeny of this genus. Several morphologically distinct species have been revealed with the aid of molecular phylogenetic methods to belong to the genus Micrasterias. A polyphasic evaluation of three species complexes within this genus also revealed an extensive hidden diversity. The last chapters summarize the knowledge about the influence of hidden diversity and accelerated morphological evolution on our understanding of diversity and biogeography of these organisms.
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Cryptic and pseudocryptic diversity of conjugating green algae (Zygnematophyceae)
Kupčíková, Eva ; Šťastný, Jan (advisor) ; Škaloud, Pavel (referee)
This bachelor thesis summarizes the most commonly used species concepts in the class Zygnematophyceae. This group of algae and the molecular markers used in the zygnematophytes' molecular phylogeny will be presented in this thesis. Zygnematophytes have unicellular or multicellular forms and they generally occur in freshwater habitats. Desmids are useful as indicators of water quality and they are also used for scoring of conservation value. Therefore it is important to have the species well defined. The confusion in defining of desmid species was caused by often very variable morphology. Some authors had different opinions on the classifying of desmid species and theirs subunits. The combination of molecular phylogeny, electron microscopy and geometric morphometrics was used in revealing of (pseudo)cryptic species in the genera Micrasterias or Xanthidium. The geometic morphometrics was helpful for finding of important details for distinguishing of particular pseudocryptic species. Key words: cryptic and pseudocryptic diversity, conjugation, desmids, Micrasterias, Euastrum, Xanthidium, molecular phylogeny, taxonomy, geometric morphometrics, biogeography, green algae
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Unveiling hidden species diversity in desmids (Desmidiales, Viridiplantae)
Šťastný, Jan ; Neustupa, Jiří (advisor) ; F.M. Coesel, Peter (referee) ; Kaštovský, Jan (referee)
The delineation of desmid species was traditionally based on purely morphological features. However, a frequent misinterpretation of morphological variability in desmids has led in the past to extensive taxonomical confusion within this important group of green algae which complicates the interpretation of their biodiversity in freshwater ecology, biogeography and biomonitoring. Consequently, I focused in this thesis predominantly on a previously neglected issue, the application of polyphasic approaches in the species-level taxonomy of desmids. In the most studies, a combination of both traditional morphological and modern molecular phylogenetic and geometric morphometric methods has been used to evaluate the taxonomy of selected desmid species, particularly representatives of the morphologically complex genera Micrasterias and Xanthidium. In two papers, I used the combination of traditional morphological and autecological data to clear up the taxonomy of several morphologically less prominent desmid taxa. Generally, the results of the thesis demonstrated that the way we recently see the diversity and distribution of desmids should be thoroughly changed. The real species diversity is mostly distinctly finer than that estimated by classical morphological taxonomy, often corresponds to varieties of...
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Measurement of Business Performance in the Company Řetězárna Ltd.
Šťastný, Jan ; Ing.Igor Lukáš (referee) ; Kocmanová, Alena (advisor)
The Bachelor thesis " Measurement of business performance in the company Řetězárna Ltd." aims to map out the company Řetězárna Ltd. financial situation in the five-year period from 2011 to 2015. The first part is devoted to the theoretical knowledge about the indicators of financial analysis. Consequently, it focuses on applying these findings to practice. The last part of the thesis is devoted to the design of solutions to improve the financial situation of the company according to the results of individual indicators of financial analysis.
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