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Diversity and relative biovolume of benthic diatom assemblages in relation to environmental conditions.
Šoljaková, Tereza ; Kulichová, Jana (advisor) ; Chattová, Barbora (referee)
iv ABSTRACT Benthic diatoms are due to a number of positive characteristics (such as high abundances, diversified communities, sensitive responses to environmental conditions, capturing long-term changes in the environmental conditions) currently the most commonly used bioindicators of the ecological status of freshwater ecosystems. However, due to problems associated with the use of traditional methods based on species composition (time-consuming identification, presence of species complexes, and requirements for calibration of water quality indexes for geographical regions) searching for alternative methods has been induced. The monitoring of the size structure of diverse diatom communities has been proposed as one of the methods. This approach would mainly eliminate the necessity of time-consuming determination of species. The main purpose of this thesis was therefore to determine the relationship between the size structure of benthic diatom communities, expressed as the relative biovolume, and selected environmental factors (pH, conductivity, habitat type) within freshwater lentic habitats. Furthermore, the variability of biovolume in dependence on environmental variables was compared with the change in species composition. If there would be a similar response pattern of both the biovolume and species...
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Ecology and Taxonomy of limno-terrestrial diatoms from East Antarctica.
Bishop, Jordan ; Kopalová, Kateřina (advisor) ; Hutňan Chattová, Barbora (referee) ; Jüttner, Ingrid (referee)
Diatoms are single-celled photosynthetic eukaryotes that substantially contribute to global primary productivity. They are also among the most diverse groups of organisms in Antarctica. Biogeographically, Antarctica is divided into three distinct regions including the Sub-Antarctic, Maritime Antarctic, and Continental Antarctic. Recent taxonomic revisions of diatoms within the Sub-Antarctic and Maritime Antarctic Regions have uncovered a number of endemic taxa initially misidentified as cosmopolitan due to species "force-fitting". Within Continental Antarctica, this taxonomic uncertainty has led to confusion about the environmental drivers of limno-terrestrial diatom communities, although this knowledge is important given the use of diatoms as regional bioindicators for environmental change. The purpose of this dissertation is to reevaluate the diatom flora of Continental Antarctica and determine variables that structure their communities within two historically and biologically important localities within East Antarctica; the Vestfold Hills and Windmill Islands. The erection of the genus Sabbea was performed to accommodate a long-misidentified species, Sabbea adminensis, that occurs within the Vestfold Hills and McMurdo Sound Region where it had been the source of taxonomic confusion since the...
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Freshwater green algae in polar regions: diversity, biogeography and methodology comparison
Šamšulová, Tereza ; Nedbalová, Linda (advisor) ; Chattová, Barbora (referee)
Green algae (Chlorophyta) are an important group of primary producers in polar regions, but they received less attention in comparison with cyanobacteria and diatoms. Environmental conditions of freshwater habitats in the Arctic and Antarctica (lakes, wetlands, streams, glaciers and snow) are very variable and microoganisms have to resist multiple extreme conditions. The overview of 58 green algal genera from polar regions showed the prevalence of representatives from the Chlorophyceae and Trebouxiophyceae, more genera were documented from the Arctic. Lakes have the highest and wetlands the lowest genus richness. This fact could be affected by uneven number of studies in both polar regions and from different habitats. The occurrence of several species has been documented only in Antarctica, but overall the green algae distribution is supposed to be rather ubiquitous. The traditional method of biodiversity research is light microscopy, which has limitations due to simple morphology of green algae. Their identificatiton at genus or species level is thus often possible only using molecular methods. While sequencing by Sanger method is used for determination of monospecific isolates, metagenome analysis allows the identification of non-cultivable or rare species. The use of combination of methods...
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Diversity and relative biovolume of benthic diatom assemblages in relation to environmental conditions.
Šoljaková, Tereza ; Kulichová, Jana (advisor) ; Chattová, Barbora (referee)
iv ABSTRACT Benthic diatoms are due to a number of positive characteristics (such as high abundances, diversified communities, sensitive responses to environmental conditions, capturing long-term changes in the environmental conditions) currently the most commonly used bioindicators of the ecological status of freshwater ecosystems. However, due to problems associated with the use of traditional methods based on species composition (time-consuming identification, presence of species complexes, and requirements for calibration of water quality indexes for geographical regions) searching for alternative methods has been induced. The monitoring of the size structure of diverse diatom communities has been proposed as one of the methods. This approach would mainly eliminate the necessity of time-consuming determination of species. The main purpose of this thesis was therefore to determine the relationship between the size structure of benthic diatom communities, expressed as the relative biovolume, and selected environmental factors (pH, conductivity, habitat type) within freshwater lentic habitats. Furthermore, the variability of biovolume in dependence on environmental variables was compared with the change in species composition. If there would be a similar response pattern of both the biovolume and species...
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