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Seasonal dynamics of mats composed by green alga Zygnema (Zygnematophyceae)
Trumhová, Kateřina
The mats formed by Zygnema spp. are well known and frequently found in streams, puddles, seepages, and ponds. Owing to the low and inconsistent water quantity of these biotopes, algae are periodically subjected to stresses like desiccation, freezing, or strong solar radiation. Recent studies have revealed that Zygnema survives various stresses in pre-akinetes, modified resistant vegetative cells. However, earlier experiments mostly aimed at osmotic stress and desiccation. Moreover, the mats formed by these algae have seasonal dynamics that have been observed several times, not only in temperate conditions but also in the Arctic. Field observations revealed that most of the biomass is periodically lost, and new mats are formed every year. Simultaneously, we know little about the genetic composition of the mats and how it changes over time; previous work has focused mainly on the mats as an entirety. Therefore, this work mainly aimed to subject the mats formed by the algae Zygnema spp. to long-term observation and subsequent experiments. We selected a region in the Austrian Alps, which we visited several times a year, and sampled two sites with different water regimes. Further research in collaboration with colleagues occurred in the Arctic. Zygnema spp. strains were subsequently isolated from the...
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Seasonal dynamics of mats composed by green alga Zygnema (Zygnematophyceae)
Trumhová, Kateřina ; Pichrtová, Martina (advisor) ; Remias, Daniel (referee) ; Žárský, Jakub (referee)
The mats formed by Zygnema spp. are well known and frequently found in streams, puddles, seepages, and ponds. Owing to the low and inconsistent water quantity of these biotopes, algae are periodically subjected to stresses like desiccation, freezing, or strong solar radiation. Recent studies have revealed that Zygnema survives various stresses in pre-akinetes, modified resistant vegetative cells. However, earlier experiments mostly aimed at osmotic stress and desiccation. Moreover, the mats formed by these algae have seasonal dynamics that have been observed several times, not only in temperate conditions but also in the Arctic. Field observations revealed that most of the biomass is periodically lost, and new mats are formed every year. Simultaneously, we know little about the genetic composition of the mats and how it changes over time; previous work has focused mainly on the mats as an entirety. Therefore, this work mainly aimed to subject the mats formed by the algae Zygnema spp. to long-term observation and subsequent experiments. We selected a region in the Austrian Alps, which we visited several times a year, and sampled two sites with different water regimes. Further research in collaboration with colleagues occurred in the Arctic. Zygnema spp. strains were subsequently isolated from the...
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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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Local dispersal of Golden-ringed dragonfly Cordulegaster boltonii
Hančíková, Barbora ; Černý, Martin (advisor) ; Dolný, Aleš (referee)
We carried out a pilot study of local dispersion and patterns of movement of Golden- ringed dragonfly Cordulegaster boltonii (Odonata: Cordulegasteridae). Cordulegasteridae is a family with many primitive traits present and rather restricted geographical distribution ranges (at least among European species). Their migration seems to be limited despite the body size that predetermines them to high mobility over large spatial scale. Linear habitat (upper parts of narrow forest streams) specialisation along with behavioural ecology (peculiar premating habit of scanning streams for females) is a unique life history, which bring lot of questions. We collected mark-release-recapture data during two adult flight seasons in year 2010 and 2011. We were simultaneously capturing patrolling males along three separate streams (Dračice, Koštěnický and Struha) in total length of 9.9 km in, located in the Natural park Česká Kanada, in the Southern Czech Republic. We captured and marked 440 individuals and recorded 113 recapture events (26 % recapture rate) in year 2010 and 355 individuals were marked, 171 recapture events made (48 % recapture rate) in 2011. Our data suggested high level of stream fidelity (only 10 inter stream dispersal events, 2.8 % dispersal rate). What was as well reflected in a closeness of...
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Mapping of water quality in Prague creeks with GIS
Thompsonová, Tereza ; Matějíček, Luboš (advisor) ; Benešová, Libuše (referee)
This thesis is focused in using of Geographic Information Systems (GIS) for mapping water quality in Prague creeks. The theoretical section focuses in a description of GIS and selected GIS projects (SWAT, ZABAGED) including a description of using GIS abroad. Working processes of chemical analyzes required to determine water quality and pollution sources in the area of urbanized basin are explained in the task. The practical section is focused in processing of data, especially mapping of selected creeks and sampling profiles using GIS. Obtained data is processed in tables and charts and used in correlation analysis. A purpose of the project was to demonstrate a possibility of GIS for modelling basin and its parameters.
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Model assessment of surface water quality in the area of the City of Prague
Pokorný, Lukáš ; Matějíček, Luboš (advisor) ; Benešová, Libuše (referee)
This thesis is concerned with analysis and brief evaluation of hydrological data provided by Lesy hl. m. Prahy company. Processing and assessment of data was carried out within two separate parts. First by means of statistical analysis and in the second section by a visual model using GIS application, method called GWR (geographically weighed regression). The data was processed through the statistical method of scattering, factoring and cluster analysis. To enable this data research a modification using MS Excel application was necessary followed by formation of a script in R application. These adjustments were inevitable due to a high number of records. The data is constituted by values of the following indicators: BSK, CHSK, nitrogen nitrate, dissolved oxygen and undissolved matter, measured within a range of eleven years in various drawing profiles of fifteen Prague streams. In the second part of this work the model was created by GWR method and by experimental attainment of various factors which could hypotethically affect the quality of surface water in the capital city of Prague. By means of statistical methods existence of several places that are negatively affected by urbanizations and human activity has been proven. Out of htese places the most affected is Komoransky stream. This fact has...
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Distribution and ecology of the turbellarian Dugesia tigrina in the Vltava river and selected Prague brooks and its interactions with native turbellarian species
Sevruková, Natálie ; Mourek, Jan (advisor) ; Hanel, Lubomír (referee)
Key words: (Dugesia tigrina), ecology, bioindication, predation, Vltava, Prague The main goal of my thesis was the research of occurrence and ecology of planarians of the group Ttricladida in the Vltava River and some brooks flowing through the territory of Prague. The emphasis was given on the non-native North American species - Dugesia tigrina. The research can be divided into field surveys of population size and ecological requirements of planarians and a laboratory experiment, in which I have investigated the predation behavior of planarians. During my fieldwork, which took place from August 22th to November 11th 2009, I have found out that the Dugesia tigrina occurs only in the Vltava river, in six of the nine studied localities. During the research it was not found in the studied brooks. It chooses localities with a natural shoreline, deeper ground, rapid water and it lives in company of mainly Dugesia polychroa. It appeared at moderately polluted places. During the predation experiment, which ran from December 17th 2009 to October 20th 2010 at a temperature of 14 řC and triple repetitions in all mutual combinations of five planarian species, intraspecific cannibalism and frequent asexual reproduction of Dugesia tigrina was comfirmed. The experiment showed mainly preying of indigenous...
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Long distance dispersal of Rumex alpinus
Řičařová, Veronika ; Münzbergová, Zuzana (advisor) ; Hadincová, Věroslava (referee)
Long-distance dispersal of Rumex alpinus was studied in the Giant Mountain in the National Park. The invasion of R. alpinus is there kind of problem. The work builds on a thesis from year 2007 (20007 Červenková), in which was made the model of the invasion of R. alpinus in the area of the Giant Mountain. The measurements of the seeds spread take place at four localities, three of them were for measuring of water dispersal and one was for measuring of winter dispersal. Anemochory was measured using traps in the meadow up to a distance of 50 m. The seeds were dispersed by wind to a distance of 20 meters. Hydrochory was measured using a network's traps in the streams up to 100 m. The largest measured water dispersal was 100 m. Hydrochory therefore proved to be an important factor, which influenced the invasion of R. alpinus. The storms and flood had the great influence on the hydrochory and anemochory. The prediction exponential curves were compiled from the data about the wind dispersal. The curves express the spread to more than a measured distance. The field dispersion curves were compared with theoretical curves, which were used in the model of the invasion from 2007. It turned out that the theoretical curves overestimate the spread of R. alpinus by wind. The dispersion of seeds was underestimated in the...
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Modeling the recovery of anthropogenically acidified mountain waters
Hardekopf, David
Thesis Summary The five chapters of this thesis consist of manuscripts published in peer-reviewed journals, focused on the effects of anthropogenic acidification on freshwater ecosystems in the Czech Republic and Slovakia, and an attempt to understand the processes and time-frame of recovery using modeling. In the Tatra Mountains in Slovakia and the Bohemian Forest in the Czech Republic, high mountain lakes have been the focus of long-term studies on both the biological and chemical impacts of acidification. The effects of anthropogenic acidification on headwater streams in the mountains and highlands of the Czech Republic have been recognized more recently, and the resulting changes to the biological community and trends in chemical changes are less well- known. Dynamic modeling, combined with the incorporation of scenarios of possible climate change, is used to investigate the present status and future trends in recovery of these ecosystems after recent reductions in atmospheric acid deposition. The first chapter is a paper on the macroinvertebrate biota in atmospherically acidified streams in the Czech Republic. This paper shows the effect of low pH on the taxonomic composition in these streams. The second chapter is focused on the current (2004) chemical composition of 91 lakes in the Tatra Mountains,...
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