|
|
Dissolved and gaseous nitrogen losses in forests controlled by soil nutrient stoichiometry
Oulehle, Filip ; Chuman, T. ; Hruška, Jakub ; Krám, Pavel ; Navrátil, Tomáš ; Tesař, Miroslav ; Ač, Alexander ; Urban, Otmar
This study investigates the consequences of chronic nitrogen deposition in forests, including its effects on soil and surface water quality, and greenhouse gas emissions. To predict these effects, the authors explore the controls over dissolved and gaseous nitrogen fluxes in temperate forests. Their findings indicate that stream leaching losses of dissolved nitrogen correspond with the nutrient stoichiometry\nof the forest floor, with stream N losses increasing as ecosystems progress towards phosphorus limitation. Soil nitrogen storage increases with oxalate extractable iron and aluminium content. The authors estimate soil gaseous losses based on 15 N stocks, which averaged 2.5±2.2 kg N ha-1 year-1 , comprising 20±14% of total nitrogen deposition. They also extrapolate the current gaseous nitrogen loss flux from forests globally to be 8.9 Tg N year-1 , which represents 39% of current nitrogen deposition to forests worldwide.
|
|
|
Estimate of carbon sequestration in the Czech Republic - afforestation of arable land, change of forest management, wetlands renaturations and tree lanes
Hruška, Jakub ; Pavelka, Marian ; Chuman, Tomáš ; Oulehle, Filip ; Vindušková, O. ; Cudlín, Pavel ; Trnka, Miroslav
Report acconunted quantitetivly as well qualitativly (for the year 2050) carbon sequestration for afforestation of arable land, change of forest management, wetlands renaturations and tree lanes.
|
|
|
Al forms in acidified surface waters - toxicity and trends
Šimková, Petra ; Hruška, Jakub (advisor) ; Hořická, Zuzana (referee)
This thesis deals with forms of aluminium occurring in acidified surface waters. Special attention is paid to inorganic monomeric aluminium, fraction, which has toxic effect on some species of aquatic and terrestrial biota. The thesis primarily focuses on the analysis of surface water, groundwater and soil water chemistry in the year-round and long-term monitoring. The practical took place on an experimental mountain basin Uhlířská, which is drained by river Černá Nisa. Uhlířská basin is located in the Jizera Mountains and represents the area which was significantly exposed to the acid atmospheric deposition in the second half of the 20th century. Long-term exposure to acid precipitation caused the acidification of soil and watercourses, forest degradation and deforestation of large parts of the basin. Decrease in pH and an increase in concentration of toxic aluminium also caused species depletion of aquatic ecosystems. Monomeric forms of aluminium were determined spectrophotometrically, the concentration of total aluminium was determined by the method of flame atomic absorption spectrometry (FAAS), in case of low concentration electrothermal atomic absorption spectrometry (ETAAS) was used. Five forms of aluminium were obtained - Altot, AlAS, Alm, Alo and potentially toxic Ali. Appart from...
|
|
| |
|
|
Mercury speciation determined by thermo-desorption analysis at two sites contaminated by mining
Hojdová, Maria ; Navrátil, Tomáš (advisor) ; Borůvka, Luboš (referee) ; Hruška, Jakub (referee)
Historic mercury mining represents an envinrnmental threat due to high llg concentration in waste materia|. Mercur1'ores \\'ere mined for more than l50 years at t\ťo siles in the centr.a| ('zech Republic, hut thc extent of Hg contamination in the vicinity of former l-lg mining sites has not been yet inr'stigatď. The objectives of the study weÍe to eva|uate thc Hg sorrrces in mine wastes. assess the extent of Hg contamination in historical ntining area ancl to cstimate potential mohility of Hg in the mine waste and soils. The method of thermal tlesorption in combination tvith Í(.P-oES (TDA-lCP.oEs) has been app|ie<l to dctermine llg speciation irr solid samples. Mine rvaste matďa| was samp|e<| at two mining sites. .|edová Hora and Svatá, in ccntral Bohemia. Three soi| profi|es were col|cclď to caphlre likely high and low impact sites rvithin the mining area at Jedová l{ora' Database of thcmto-<|esorption cun,cs o[ I{g chemica| conrpottnds ant| rcference materia|s was crcated for the TDÁ ftrr comparativc purposes. Both mine wastes and soils collected near the llg nines were highly elcvated in total l-lg corcentrations (up to 120 pg g-r and l0 pg g-', respectively). Soils exhibited the highest tlg concentrations mostly in subsurface Ah soil horizons. Higher lJg concentrations in Ah horizons relative...
|
|
|
Generating Methods in GR and Properties of the Resulting Solutions
Hruška, Jakub ; Žofka, Martin (advisor) ; Pravdová, Alena (referee) ; Gürlebeck, Norman (referee)
The use of conformal transformation as a method for generating solutions of Einstein's equations has been mainly studied in the cases where the original spacetime is vacuum. The generated spacetimes then frequently belong to the class of pp-waves. In the present work, the electrovacuum spacetimes are stud- ied, i.e the solutions of coupled Einstein's and Maxwell's equations. By using the conformal transformation, it is possible to circumvent solving the later equa- tions. This method is concretely studied for null Einstein-Maxwell fields and it turns out that the admissible spacetimes are pp-waves again. However, if the method is generalized, it is possible to enlarge the class of conformal null Einstein-Maxwell fields to a wider family of Kundt spacetimes. 1
|
|
|
Acid/base character of dissolved organic carbon in soil and surface waters
Vanerová, Zuzana ; Hruška, Jakub (advisor) ; Kaňa, Jiří (referee)
This thesis deals with acid-base properties of dissolved organic carbon (DOC), which markedly affect chemistry of surface and soil water in mountain catchments. It describes long-term trends of acid-base character of organic acids (humic and fulvic acids) in two acid-impacted peaty catchments Tajga and Černý potok in Slavkov Forest, western Czech Republic between 1993 - 2010. Area was significantly acidified by sulfur emission from coal-burning power plants in the region which burned coal with a high content of sulfur (1 - 15 %). These power plants were desulphurized between 1994 - 1999 and observed changes are significantly affected by decrease of strong mineral acids atmospheric deposition. Changes during the period 2006 - 2010 were also studied in soil waters from Načetín in Ore Mountains. There are three forest stands - spruce, beech and limed spruce stand. Limed spruce stand was limed in August 2007. For an evaluation of similarity of acid/base character of DOC samples from Sweden, Portorico and Congo were also taken. Many studies examined DOC acid/base character using different analytical methods. These methods produced different and hardly comparable results. In this work rightness, reproducibility and errors of one of these methods - titration after transfering acids to H+ cycle - was tested. Method...
|
|
|
Sediments of Bohemian Forest lakes and their use in paleoenvironmental research
Vondrák, Daniel ; Tátosová, Jolana (advisor) ; Hruška, Jakub (referee) ; Kyška Pipík, Radovan (referee)
Sediments of Bohemian Forest lakes are important natural archives. Their sedimentary record covers postglacial history of the lakes as well as history of natural processes in a wider region. It also documents local settlements and changes in landscape management. The lake sediments have attracted the interest of the scientific community since the end of the 19th century. Despite of the fact that modern paleolimnological and paleoecological investigations were already performed in the second half of the 20th century in the Bohemian Forest Mts., the great potential of the lake sediments was not fully utilized in scientific research so far. The ultimate objective of this thesis is to deepen knowledge of these natural archives and support their utilization in future studies. Several specific objectives have been set to achieve the ultimate objective: i) to compare age of the Bohemian Forest lake sediments with the recent knowledge of local deglaciation at the end of the last ice age, ii) to integrate chronostratigraphic marker horizons as one of the tools of Late Glacial sediment dating, iii) to assess the role of bioerosion in chitinous subfossil freshwater invertebrate remains on the record representativeness, and iv) to prove the presumed dystrophic nature of the lakes during the Holocene using...
|
|
|
Oxalates in rocks and plants
Novotná, Julie ; Jehlička, Jan (advisor) ; Hruška, Jakub (referee)
SUMMARY: The presence of oxalates is widespread not only as kidney stones, but in whole nature. It is well known that oxalates are products of some plants, fungi and lichens. The accumulates of calcium oxalates are increased in: sorrel, rhubarb, spinach, soya, dieffenbachia, etc. Oxalates serve many important functions in plants such as calcium regulation, protection from herbivory and metal detoxification. Aluminum detoxification is ability of plants, which is critical factor for crop production. Breeding of commercially viable low oxalate cultivars or genetic manipulation with crops should deal to enhance of nutritional quality and enhance of agricultural production too. The presentation of oxalates in rocks is well representing by calcium oxalate minerals, whewellite and weddellite. Minerals occur in sediments into precipitated forms within concretions and hydrothermal veins or dispersed form into modern sediments, e.g. peats. Oxalates are biologic products, therefore they can indicate biological activities, so oxalates should be sought for researching on cosmic objects. The observation of oxalates on Earth and interpretation of the Raman spectra is necessary in these types of study.
|
|
|
Generating Methods in GR and Properties of the Resulting Solutions
Hruška, Jakub
The use of conformal transformation as a method for generating solutions of Einstein's equations has been mainly studied in the cases where the original spacetime is vacuum. The generated spacetimes then frequently belong to the class of pp-waves. In the present work, the electrovacuum spacetimes are stud- ied, i.e the solutions of coupled Einstein's and Maxwell's equations. By using the conformal transformation, it is possible to circumvent solving the later equa- tions. This method is concretely studied for null Einstein-Maxwell fields and it turns out that the admissible spacetimes are pp-waves again. However, if the method is generalized, it is possible to enlarge the class of conformal null Einstein-Maxwell fields to a wider family of Kundt spacetimes. 1
|
guest ::
