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Chrysophycean cysts and scales in paleolimnological studies
Bartošová, Kateřina ; Němcová, Yvonne (advisor) ; Škaloudová, Magda (referee)
This thesis deals with chrysophyte scales and stomatocysts as useful tool of paleoecological reconstructions in lake ecosystems. In the first part the geological physical and biological aspects of lake reconstructions are described. The second part contents information about chrysophyte taxa and their utilisation as paleoekological indicators. Chrysophyte microphosils include two major groups of siliceous indicator: stomatocysts and sculptured and ornamented species-specific scales. Using surface-sediment training sets, quantitative inference models have been constructed for eutrophication, acidification, air-born pollution, salinification, climatic change, and other environmental changes. This thesis represents a literature review.
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Ultrastructure of eustigmatophycean algae
Fišerová, Melánie ; Němcová, Yvonne (advisor) ; Hyliš, Miroslav (referee)
In 1971, the algal class Eustigmatophyceae, Stramenopiles, was detached by Hibberd and Leedale from the class Xanthophyceae, Stramenopiles, on the basis of prominent ultrastructural differences in vegetative cells and more importantly in zoospores, such as the presence of big extraplastidial stigma. The class was divided into four families, six genera and twelve species. It seems so far, that there is a deep dichotomy within the class. Eliáš et al. (unpublished) recom- mend to establish two orders based on molecular sequencing of 18S rDNA and rbcL: Eustigmatales (sen- su Eustigmatophyceae described by Hibberd) and Goniochloridales (order containing Goniochloris, Pseu- dostaurastrum and undescribed relatives). The order Eustigmatales is divided into three separate lineages, most likely families: Eustigmataceae (A1), Monodopsidaceae (A2) and a new family Pseudellipsoidiona- ceae (A3). In this study the ultrastructure of 10 eustigmatophycean strains from three separate lineages was investigated. The typical characteristics of this class as chloroplast without a girdle lamella, a reddish glo- bule and lamellate vesicles were found in all strains studied. The appearance of the lamellate vesicles was found to change during the life cycle. My research indicates that other characteristics, formerly...
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Climate change and related species shift in algal and cyanobacterial communities.
Kosová, Alena ; Němcová, Yvonne (advisor) ; Pichrtová, Martina (referee)
Therefore, species are expected to move towards the poles in response to shifting climate ones. This warming trend also includes the establishment of tropical algae in temperate systems of the Northern Hemisphere. Numerous tropical and subtropical species of microalgae have been reported in the last decades in the continental waters of Europe. The aims of the Bachelor thesis are to summarize articles concerning changes in diversity and dynamics focused on algae and blue-green algae in temperate water bodies. Several hypotheses about the origin, modes of distribution and the ability of microorganisms to overcome stressful condition during the transportation are also discussed in this work.
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The role of microhabitats in spatio-temporal differentiation of freshwater algal assemblages
Pusztai, Martin ; Němcová, Yvonne (advisor) ; Kulichová, Jana (referee)
This thesis deals with microhabitats in relation to the spatio-temporal differentiation of freshwater algal assemblages. Algae are defined ecologically, althought they represent a diverse polyphyletic conglomerate. Based on the available literature, type of substrate appears as a suitable representative of most freshwater microhabitats when comparing results from different studies. Influence of microhabitat may occur not only on a small spatial scale, but also on a regional scale. The importance of scale and traceability of different factors are further discussed as well as the appropriate definition of the microhabitat. Microhabitats diversity is often reflected in the spatial heterogeneity of algal assemblages. Based on the common trends in the algal life strategies, erosional and depositional substrates can be distinguished. Living substrates, especially macrophyte surfaces represent a special category of microhabitats. Algae can enter complex interactions with these living substrates.Temporal dynamics is relatively less explored in comparison with the spatial heterogeneity.
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Synura echinulata (Synurales) - silica scale plasticity in natural populations influenced by environmental factors; accompanying scaled chrysophytes
Kreidlová, Jana ; Němcová, Yvonne (advisor) ; Hodač, Ladislav (referee)
The silica scale shape variation in Synura echinulata has been investigated only in laboratory conditions, so far. The aim of this thesis was to study scale shape variation in natural populations and to determine which environmental parameters influence the scale shape. The scale shape variation was investigated using landmark-based methods of geometric morphometrics. Scale shape changes related to environmental factors were analyzed using the two-block method PLS (Partial Least-Squares analysis) and adonis (R). The scale shape was mostly influenced by locality, pH and altitude. Shape distinguished populations of S. echinulata probably exist in different localities. The more distant localities are, the less similar are scales of S. echinulata in their shape. This scale shape variation is probably genetically determined, even thought all so far sequenced populations belong to the same species. High morphological disparity which was probably caused by anthropogenic pollution, was recorded in the locality Brdy. During sampling of the natural populations of Synura echinulata in the Czech Republic, several localities representing a significant reservoirs of species diversity, were found. Therefore, the thesis was extended and biodiversity research in the Czech Republic was added. A few samples were...
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Vertical migration of benthic cyanobacteria and algae
Mensa, Jakub ; Neustupa, Jiří (advisor) ; Němcová, Yvonne (referee)
Vertical migration has been observed in different taxonomic groups of benthic microalgae and cyanobacteria in both marine and freshwater habitats. It seems to be an advantageous survival strategy of motile photoautotrophic organisms. In general, algae inhabiting tidal environments migrate up to the sediment surface during daytime emersion and then migrate below the surface prior to high tide or dusk. Freshwater microalgae stay on the surface during daytime and migrate below the surface before dusk. The migratory rhythm can be controlled or influenced by light, waves, subsurface nutrient supplies and reducing conditions in the sediment. Sometimes, the rhythm persists even in constant conditions and it seems to be controlled by biological clock system.
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The changes of species composition of soil phototropic microorganisms on the altitude gradient in E Ladakh
Janatková, Kateřina ; Němcová, Yvonne (advisor) ; Hrouzek, Pavel (referee)
Abundance and diversity of microbial phototrophic communities (cyanobacteria and eukaryotic microalgae) were investigated at two localities in main mountain ranges of Ladakh (Tibetan Plateau and Eastern Karakoram), India. Samples were collected along a two representative altitudinal gradients at each locality (E Karkoram 4620 - 5100 m asl., Tibetan Plateau 5346 - 5833 m asl.) in alpine and subnival zones in the vicinity of cushion plant Thylacospermum caespitosum (Caryophyllaceae). At each altitude 6 soil samples were taken from below cushion and 6 samples from outside the cushion. The epifluorescent microscopy and DGGE-method were used to determine diversity and biomass of phototrophs in the studied soils. Physico-chemical analyses (pH, texture, organic matter, nitrogen, ammonia and phosphorus content, concentration of chlorophylls and carotenoids) were also performed on the samples. The effect of altitude, mountain ranges and T. caespitosum on the composition and biomass of phototrophs and physico-chemical parameters of soil was tested by multivariate redundancy analysis and variance partitioning procedure. This study shows that the semiarid and arid soil of high elevation in Ladakh Mts. is suitable place for the development of microbial phototrophic communities and is important part of the ecosystem. The...
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Shape dynamics of silicate structures in experimental populations of chrysophytes (Synurophyceae)
Pichrtová, Martina ; Němcová, Yvonne (advisor) ; Elster, Josef (referee)
The aim of the proposed diploma thesis was to analyze temperature and pH related shape variation in synurophyte silica scales. Four species were investigated - Synura petersenii, S. echinulata, S. sphagnicola and Mallomonas tonsurata. The strains were cultivated in 5 different temperature levels. Moreover, S. petersenii and M. tonsurata were grown in 4 (resp. 5) different pH levels, too. The shape dynamics of the scales was investigated with application of landmark based geometric morphometric methods. The relative warps analysis described the overall shape and the main trends in morphological variation were depicted as deformation grids. The effects of both cultivation temperature and pH on the scale shape were significant, although only a small proportion of the overall variation was explained by the particular regression models. Moreover, the scale size of the investigated species decreased with increasing temperature (with the exception of Synura echinulata). These results are in agreement with the Atkinson's temperature rule which was formulated for the body size of ectotherms. The relationship between the size and pH was not explicit - the size of the scales decreased with increasing pH in S. petersenii, but increased in M. tonsurata. Furthermore, the scale shape was also found to be related to the...
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