National Repository of Grey Literature 3 records found  Search took 0.00 seconds. 
Natural sources and sinks of volatile chlorinated hydrocarbons in the spruce forest ecosystem
Štangelová, Pavla ; Tesařová, Eva (advisor) ; Pavlík, Milan (referee)
Biogeochemical cycle of chlorine, particularly the formation of organically bound chlorine is still not well understood. In continental ecosystems chlorides act as source of chlorine, and also as a stress factor. Chlorides originate from precipitation of marine cloud masses. Organically bound chlorine in the environment is formed naturally by biotical and abiotical way. The biotical factors are microorganisms, plants, soil enzymes and animals. Volatile chlorinated hydrocarbons (VOCl) represent one group of organically bound chlorines. Several volatile chlorinated hydrocarbons reacts with atmospheric ozone, consequently causing depletion of the ozone layer. The most important known terrestrial source of volatile chlorinated hydrocarbons is the spruce forest ecosystem. Chlorine in the soil can be transformed by microorganisms into organically bound chlorine or translocated by transpiration stream in plants, where they are also transformed enzymatically into organically bound chlorine, and both of them can be emitted into the atmosphere. Too large amounts of chloride can affect the physiological functions of plants. In this thesis experiments were designed for measuring the natural emissions of volatile halogenated hydrocarbons from plants and fungi, with various periods of incubation, and also to...
Monitoring of the occurence of Cyanobacteria in the Seč water resevoir by analytical methods
Štangelová, Pavla ; Tesařová, Eva (advisor) ; Cajthaml, Tomáš (referee)
Cyanobacteria are one of the oldest living organisms on the planet Earth. They are able to survive in different conditions under various conditions, almost in all habitats. The growth of cyanobacteria is affected by the amount of nutrients present in the environment, especially nitrogen and phosphorus, and by the climatic conditions. In larger quantities cyanobacteria began to spread in past few decades due to human activities. As a result of excessive use of fertilizers and washing nutrients from the soil is human-caused eutrophication and expansion of the so-called "water bloom". The presence of cyanobacteria in water is monitored using various analytical methods. The occurrence of cyanobacteria on the water reservoir Seč was determined by fluorimetric detection of pigment c-phycocyanin in samples of natural waters and compared with chlorophyll a content in these samples. Key words: cyanobacteria, c-phycocyanin, chlorophyll-a, fluorimetry
Natural Sources of Chlorinated Volatile Hydrocarbons in Spruce Forest Undergrowth
Štangelová, Pavla ; Wimmer, Zdeněk ; Tesařová, E. ; Forczek, Sándor
Chlorine as one of the most frequently occurring elements in nature, is involved in biogeochemical\ncycles. Several anthropogenic and even natural sources of volatile chlorinated hydrocarbons of\nemission is known, yet natural sources have not been explored enough. The aim of this study is to\ngather information of potential sources of chlorinated organic hydrocarbons in spruce forest\nundergrowth. Emissions of chlorinated volatile hydrocarbons of selected species of bryophytes,\nferns and fungi were measured by SMPE sampling technique and analyzed with GC-MS analysis.\nSodium chloride solution was used as a stressor to simulate increased environmental chloride load.\nTrichloromethane (chloroform) was found in most natural samples, dichloromethane,\ntetrachloroethene and tetrachloromethane were found occasionally. Increased chloride\nconcentration caused elevated emissions of trichloromethane and tetrachloromethane in some plant\nspecies.

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