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Diatoms were studied in 29 spring fens of the West Carpathians. A total of 70 diatom taxa were found. Caloneis tenuis, Eunotia paludosa, E. steineckii, Navicula cryptocephala, Nitzschia archibaldii, Rhopalodia gibba and R. rupestris were the most frequent species. The sites with low pH (3,6 – 6,5) can be characterized by the occurrence of genera Anomoeoneis, Eunotia, Frustulia. On the other hand, Rhopalodia and Diploneis were common at the sites with higher pH (6,4 – 7).
The contribution presents the results of the first investigation of phytoplankton in the district of Prostějov. During 1998-1999 seasonal changes of phytoplankton in two fishponds together with selected physical and chemical parameters (temperature, oxygen, pH, conductivity, nutrients and heavy metals) were investigated. Eutrophication of the investigated fishponds is not as high as in other regions in the Czech Republic.
Wet stones near the wells form a specific microhabitat for the occurrence of epilithic, benthic and epiphytic cyanobacteria and algae. In four wells (Prosba lesa, U sovy, Čertík, U památníku letců) 15 little known cyanobacteria species (namely from the group of Chroococcales) were identified. These microhabitats belong to oligosaprobic water sites.
The article focuses on statistical evaluation of algal bioassays. Statistical determination of EC50 and determination of low effect concentration is a very important part of presentation of ecotoxicological experiments. The question is, what is NOEC and LOEC in algal bioassay. The paper discusses the question how large difference between the sample and control algal growth should be considered as important. How large differences of algal growth in comparison to control means there is no important difference?
DAPI fluorescent staining was used to record cytomorphological changes in cyanophytes during the process of digestion by some mosquito larvae. Control cells were red due to fluorescence of chlorophyll and DNA structures (nucleoids) stained with DAPI emitted strong bluish light. Morphology of Cyanothece, Cyanobacterium, Merismopedia, and all Synechococcus strains dramatically changed along the gut. In the foregut, cells did not apparently differ from control. In the hindgut however, no chlorophyll fluorescence was observed, cells exhibited weakly bluish or yellowish fluorescence (typical for dead cells) and no DNA material or polyphosphate granules were observed. However the cells were not apparently broken (except of Cyanothece). The sequence of degradation of the material was chlorophyll, polyphosphate granules and DNA structures. In the strains of Arthrospira, Chroococcus, Microcystis and both Synechocystis strains no fundamental morphological differences were observed among the cells located in fore- and hindgut.
This contribution deals with the comparison of several physical and chemical parameters and algae periphyton in the Ostravice River above and below the Šance Reservoir. The Šance Reservoir on the Ostravice River (North Moravia) is a typical deep reservoir with the hypolimnetic outflow during the period of stratification. The reservoir serving as drinking water supply was filled up in 1969. Temperature, pH, conductivity and concentrations of oxygen and nitrogen compounds, as well as the phyto-periphyton changes (focussed on diatoms and assessment of saprobity) were followed in the five profiles on the Ostravice River. Special attention was done on the morphological variability of the diatom species Fragilaria arcus (EHRENBERG) CLEVE. Two profiles studied were located on the reservoir inflows, three below the reservoir dam. The decrease of oxygen concentrations, pH, conductivity and saprobity was observed below the dam. Concerning water temperature, the decrease of summer water temperature values and increase of water temperature in winter were found below the reservoir. While the concentrations of NO2- and NH4+ and the morphological variability of the species Fragilaria arcus were not significantly different in the profiles studied, the NO3- concentrations were higher below the dam.
Ten genera of cyanophytes and 73 genera of algae were found in the guts of Aedes, Culex, Anopheles and Culiseta larvae collected in various breeding places of the Elbe-Lowland (Bohemia) and Prague. The quality and quantity of blue-green algae and algae found in mosquito guts depended on their presence in the water of mosquito breeding places and on the feeding type (filter fieders, scrapers) of mosquito larvae. Chlorophycean algae possesing cell wall with sporopollenin and algae with a mucilagenous (jelly) envelope appeared undamaged by the digestive process. Also spores and resting stages tended to pass undamaged through the larval intestine tract.