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Chironomid fauna of acidified mountain waters
Malá, Martina ; Tátosová, Jolana (advisor) ; Vondrák, Daniel (referee)
Acidification of freshwater ecosystems peaked in 1980. There were overall changes in the chemistry of surface waters. As a result, some fish and sensitive species of zooplakton and zoobenthos disappeared. After the peak, emissions of major pollutants (SO2, NOX a NH3) declined significantly, which started the process of recovery from acidification. Nevertheless, biological recovery proceeds very slowly and it is not clear whether it is a completely reversible process. Chironomids serve as a very useful tool to assess acidification and recovery processes, mainly due to their toletance and also sensitivity of species to low pH, concentration of dissolved oxygen, nutrient content and adaptability to changes in food supply. Chironomids have in general high adaptability of species to harsh conditions. Food supply and concentration of dissolved oxygen are likely the main factors which influence the assemblages of chironomids in freshwater ecosystems. Chironomids are suitable for use in surface water research and biomonitoring due to their world-wide distribution, high species diversity and density. In comparison to other families of zoobenthos there is far less studies of chironomid assemblages, because of demanding determination. The CPET method, which uses collection of pupal exuviae, has great potential...
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Palaeoenvironmental reconstruction of the Younger Dryas based on fossil chironomids
Skurčáková, Anežka ; Tátosová, Jolana (advisor) ; Bitušík, Peter (referee)
The final stadial of the last glacial - Younger Dryas (12 650 - 11 500 cal yr BP) is relatively well described in sediments of European lakes, however research related to its progress in Central European area is missing. The goal of this thesis was to examine progress of this stadial based on sediment core from Černé Lake at Šumava (Czech Republic). To reconstruct climatic conditions, sub-fossil remains of Chironomidae was used. The air July temperature was estimated using Swiss-Norwegian model. Geochemical analysis was performed to determine intensity of erosion, trophic status of the lake, and sources of its organic matter. To complete information about catchment, pollen analysis was performed. Following climatic events were identified in the sediment: Older Dryas (13 583 - 13 394 cal yr BP), Alleröd (13 394 - 12 383 cal yr BP), Younger Dryas (12 383 - 11 394 cal yr BP) a Early Holocene (11 394 - 11 138 cal yr BP). Presence of two phases of Younger Dryas was not significantly proven, nevertheless, the isotope composition suggests, that the first half of this oscillation was drier. Reconstructed temperature ranged between 8,30 and 10,31řC. The mean temperature for Older Dryas event was 8,92 řC, for Alleröd 9,61 řC, Younger Dryas 9,17 řC and Early Holocene 10,00 řC. Reconstructed temperature...
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Chironomid fauna of acidified mountain waters
Malá, Martina ; Tátosová, Jolana (advisor) ; Vondrák, Daniel (referee)
Acidification of freshwater ecosystems peaked in 1980. There were overall changes in the chemistry of surface waters. As a result, some fish and sensitive species of zooplakton and zoobenthos disappeared. After the peak, emissions of major pollutants (SO2, NOX a NH3) declined significantly, which started the process of recovery from acidification. Nevertheless, biological recovery proceeds very slowly and it is not clear whether it is a completely reversible process. Chironomids serve as a very useful tool to assess acidification and recovery processes, mainly due to their toletance and also sensitivity of species to low pH, concentration of dissolved oxygen, nutrient content and adaptability to changes in food supply. Chironomids have in general high adaptability of species to harsh conditions. Food supply and concentration of dissolved oxygen are likely the main factors which influence the assemblages of chironomids in freshwater ecosystems. Chironomids are suitable for use in surface water research and biomonitoring due to their world-wide distribution, high species diversity and density. In comparison to other families of zoobenthos there is far less studies of chironomid assemblages, because of demanding determination. The CPET method, which uses collection of pupal exuviae, has great potential...
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Disperzní a letová aktivita pakomárů stojatých vod (Diptera: Chironomidae)
VEBROVÁ, Lucie
I first review the significance of dispersal for individuals and populations including the role of the most significant environmental drivers on separate phases of dispersal. Emphasis is put on aquatic insects inhabiting small standing waters. The following manuscript summarizes a quantitative study of diel and seasonal flight patterns of adult Chironomidae in the Cep II sandpit in southern Bohemia. It provides one of the first comprehensive treatments of the effect of weather conditions and seasonality on the flight activity of adult Chironomidae, phenology of most common species and differences between terrestrial and aquatic species.
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Seasonal changes in macrozoobenthos of the Brno reservoir during water level manipulation
OPATŘIL, Jan
There is a number of measures, which have been currently performed on the Brno Reservoir, with the aim at the recovery of the environment health and at the reduction of incidence of cyanobacterial water blooms. The main intervention in this efforts was the desrease of water level in 2009-2010, when the level was reduced by up to 9 m. This intervention resulted in drying of the uncovered area of the littoral bottom and in completely changed oxygen conditions in the remaining lake. The objective of my work is to evaluate changes in benthic macroinvertebrate assemblage in response to these interventions and measures. On the sites of the reservoir, selected with respect to water levels and in-depth ratios, macroinvertebrates were seasonally sampled by the Ekman grab and kick-off approach in deep muddy sites and in the littoral zone, resepctively. Samples were collected at the ?Hráz?, ?Střed?, ?Litorál?, ?Rakovec?, ?Zouvalka?, ?Rokle? and ?Horní vzdutí?. In parallel with sampling selected environmental parameters (temperature, O2) in epilimnium hypolimnium were measured. The samples were washed and conserved for later determination and quantification in the laboratory. All macroinvertebrate samples were divided into three groups: Chironomidae, Oligochaeta and Others. The result are presented in a graphical form as the biomass and density on different sites according to the years preceding the reservoir draining, during the water level decline and afterwards and discussed in association with certain abiotic factors.
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