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Three years long investigation of fishpond Dehtář - first fishpond in the NETLAKE COST action project
Potužák, Jan ; Šumberová, Kateřina ; Fránková, Markéta ; Fabšičová, Martina ; Ducháček, M. ; Císař, K. ; Duras, J.
In 2014–2016 we monitored basic environmental parameters in the fishpond Dehtář near České Budějovice (Czech Republic) using system of sensors. Among other parametres we studied for instance water chemistry and phyto- and zooplankton community biomass, and species composition. Thank to the method used we recorded strong fluctuations in some of the environmental parameters, parrticularly in oxygen concentrations. Thank to the integration of the auomatic high frequency monitoring using the sensor system along with traditional research methods we were able to interpret the marked ecosystem changes. Several factors participated in the several days long oxygen depletion: warm and calm weather, later interchanged by cold front accompanied with mixing of water column and cloudy sky, fish farming management (high amount of nutrients related to manuring) and changes in biomass of phytoplancton (fast decomposition of high biomass amount of cyanobacteria). Our results enable to prevent similar situations in future, by e.g. lowering of nutrient input.
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Monitoring of water quality in the river Stropnice
Petrlíková, Kateřina ; Tesařová, Eva (advisor) ; Potužák, Jan (referee)
Five indicators of water quality, namely biochemical oxygen consumption in five days, chemical oxygen consumption by dichromate method, nitrate nitrogen, ammonium nitrogen and total phosphorus, were determined in the river Stropnice. The samples were monitored at four offtake places along the river monthly during the year 2013. Twice a year water samples were analyzed also fromthe dischargeof the wastewater treatment plants. The results show that some changes of the individual parameters can be traced during the year, such as increase of oxygen consumption and total phosphorus in the summer months. However, no significant fluctuation was indicated for the measured parameters at any of the offtake places. Based on the values of the individual parameters water in Stropnice can be ranked to quality classes II. - IV. In the long-term frame of water quality examination from the year 2008 average indicators' values and characteristic values were determined. The results revealed that neither in this case substantial changes of water quality regarding the measured indicators can be observed.
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Growth of aquatic vegetation in fish ponds used for recreation - Bolevecká soustava near Plzeň.
Pták, Martin ; Duras, Jindřich (advisor) ; Potužák, Jan (referee)
The aim of this diploma thesis was to clarify the differences among three different ponds (Bolevecký, Třemošenský, Šídlovský) situated in Pilsen. All of the above mentioned ponds are recreational areas where Bolevecký pond is best known for his water quality improvements since 2006 (after application of Fe and Al - colagulants and also fish - stock changes). The main difference was based on the growth of submersed water plants. The macrophytes were growing slowly or not at all in Bolevecký pond. There was a huge expansion of macrophytes (mainly Myriophyllum spicatum species) in Třemošenský and Šídlovský ponds therefore the water plants must be regulated during summer seasons by mechanical harvesting. The water in all three ponds proves the same qualities but the differences may be found in the nutrient composition of sediments. The fractionation analysis (the founders Psenner and Puczsko) confirmed the fact that all localities are poor in phosphorus however the differences were found in content of iron. The increased content of iron was observed in sediments of Šídlovksý and Třemošenský ponds (mainly in BD fraction - the iron was unstable under redox potential changes). The result of this analysis proves that phosphorus is potentially more available for macrophytes in sediments of Třemošenský and Šídlovský...
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Fishpond sediment – new approach to the nutrient recycling in the agricultural landscape
Potužák, Jan ; Duras, J. ; Kröpfelová, L. ; Šulcová, J. ; Chmelová, I. ; Benedová, Z. ; Svoboda, T. ; Novotný, O.
Possibilities of the use of the fishpond sediment in the improvement of arable land is discussed. Among others, this approach has a high potential to contribute to the recycling of phosphorus in the agriculture landscapes. For this purpose, we propose set of particular techniques which were tested in the field study.
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Fishponds and water quality
Duras, J. ; Potužák, Jan ; Marcel, M.
Most of the fishponds in the Czech Republic is highly eutrophic to hypertrophic. This situation is related to the run-off in the catchments and by the fis-farming management (especially fertilisation). Long-term monitoring of fishpond water quality is complicated by large spatiotemporal variability of the parameters measured.
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Utilization of System LISp-Miner in the Analysis of the Factors Influencing the Dominance of Cyanobacteria in Phytoplankton
Hlaváčová, Tereza ; Šimůnek, Milan (advisor) ; Potužák, Jan (referee)
The aim of this work is to describe steps associated with solving analytical questions using the LISp-Miner in the data from water-analyzes of 12 ponds in South Bohemia in the period from year 2007 to 2012. Analytical questions are primarily focused on issues of cyanobacteria, based on instructions of data-owner, Povodí Vltavy, státní podnik. Apart from a description of the application of procedures KL-Miner, CF-Miner and 4ft-Miner on data, the work aims to prepare an automating process based on steps made during using procedures. The theoretical part is a summary of the basic concepts and principles associated with association rules and GUHA method. The practical part follows the CRISP-DM methodology. The result is a proposal of automation process by which it is possible to look for interesting rules in the hydrobiological and hydrochemical data. Then there is a set of recommendations for better utilization of database for KDD, with proposals how to modify and prepare the data.
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