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Role of microbes in the decomposition in headwater streams.
Kociánová, Petra ; Kopalová, Kateřina (advisor) ; Tátosová, Jolana (referee)
The decomposition of organic matter in headwater streams is a key process in stream ecology and an important component of the global carbon cycle. Decomposition rates depend on both abiotic and biotic factors, the former including temperature, discharge, and nutrient chemistry, and the latter including stream community structure and activity, trophic interactions, biodiversity, and productivity. Of the stream community, microbial decomposers play a particularly important role in decomposition by chemically degrading compounds and transferring nutrients and energy to higher trophic levels. These processes are prone to change due to current and future global warming which will affect both decomposer communities and associated decomposition rates. This thesis provides a short overview of the main factors that control stream decomposition rates, including biological factors like microbial activity, abiotic factors such as water temperature and nutrient availability, and how these factors may be altered in the future under a warmer climate. Specifically, I predict that climate change will increase microbial activity and decomposition in headwater streams due to increased water temperatures, changes in surrounding vegetation, and shifts in the hydrological regime due to global warming. .
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Use of microbial community structure as a marker of conditions in underground biotops
Burkartová, Kateřina ; Falteisek, Lukáš (advisor) ; Drahota, Petr (referee)
The amount of data obtained by barcoding of prokaryotic 16S rDNA from natural habitats is increasing exponentially. Thus, methods enabling us to extract useful information from these data are of increasing importance. In this thesis microbial communities from water, sludge and drilling dust were analyzed by 16S rDNA sequencing in three geologically well described sedimentary aquifers in Bohemian Massif. The main goal of this research was to establish how different analytical approaches can be useful in interpretation of groundwater biogeochemical processes. Three approaches were used: First, taxonomy and metabolic traits of the most abundant microorganisms were assessed. Second, ordination methods showing metabolic and taxonomic variability between communities were used. Last the analysis of phylogenetic dissimilarity using UniFrac metrics was performed. When analyzing individual localities separately, the shift in microbial community composition corresponds with the change of environmental conditions. The unconstrained ordination method based on the variability in metabolic traits indicated, that sludge samples are more informative than water samples when asking which electron donor is used in microbial communities. On the other hand, unconstrained ordination methods were useless when the...
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