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Genetic potential for methane metabolism in the Greenland subglacial ecosystem
Rybár, Marek ; Stibal, Marek (advisor) ; Šabacká, Marie (referee)
Subglacial environments, located at the interface of glacier ice and bedrock, represent one of the major ecosystems associated with glaciers and ice sheets. This environment contains liquid water and underlying sediment with large amounts of organic matter overridden during periods of ice advance. Large areas of subglacial sediment are exposed annually by glacier melting and retreat, which affects the subglacial carbon stores and may significantly impact regional carbon fluxes. Due to the widespread anoxia at glacier beds, subglacial environments are potential producers and reservoirs of methane that can be released into the atmosphere as a consequence of glacial retreat. While the presence of methanogens and methane oxidisers has been shown based on 16S rRNA gene data, no data on the functional genetic potential for methane metabolism currently exist. In this study, the first subglacial metagenomes obtained from subglacial sediment exported from beneath the Greenland ice sheet by a meltwater river were used to characterize the metabolic potential for methane metabolism by the identification and quantification of genes involved in methane production and consumption. Functional genes of potential syntrophic pathways were also investigated. Functional genes of methanogenesis/anaerobic oxidation of methane and...
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Influence of pH on Extraction of Matter from Biochar-Soil Complex
Jakubčeková, Kristína ; Enev, Vojtěch (referee) ; Kalina, Michal (advisor)
Biochar is one of the possible solutions to improve the soil fertility, therefore it is necessary to investigate both its composition and the impact on the soil under various conditions. The aim of this bachelor thesis is to focus on the description of the influence of pH on the amount and type of substances (molecules, ions) that are leached from the biochar into the soil and thus consequently influence its properties. As a soil model it was chosen cambisol which is the most widespread soil in the Czech Republic. The selected pH values have been defined in such a way to cover the pH range that is common for various soil types in natural conditions. In the experimental part of this thesis the extracts from the used sample of biochar and soil were characterized first. These characteristics obtained in this way were subsequently compared with the data obtained for the biochar-soil complex extracts that was obtained after a defined period of cultivation of the mixture. For the characterization of extracts the basic physico-chemical methods (pH, conductivity, elemental and thermogravimetric analysis, UV-VIS) and also the analysis of leached ions and molecules by means of ICP/OES, GC-MS were used. Evaluated experimental data show that under the condition of cultivation experiments, the influence of biochar was observed only on the basic physico-chemical characteristics of the soil (mainly pH). On the other hand, there was no significant tendency of the impact of biochar on the representation of selected elements and on the content of organic matter in the soil. Long-term biochar-soil cultivation experiments could be a suitable solution.
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The importance of mycorrhizal fungi in the root decomposition.
Haiclová, Klára ; Kohout, Petr (advisor) ; Kolaříková, Zuzana (referee)
Mycorrhizal fungi are known as symbionts of many plant species. Fungi provide better access to mineral nutrients and water for host plants, and in return fungi receive carbohydrates from plants. Although a significant proportion of organic matter is bound in the root biomass, little is known about the factors affecting root decomposition. Understanding the process of root decomposition and the factors that affect it, is important to us. Knowledge of root decomposition helps us understand the carbon cycle and answer questions about carbon sequestration in soil. This Bachelor's thesis is focused on the importance and function of mycorrhizal fungi during root decomposition. It describes the influence of mycorrhizal fungi on the decomposition of fine roots colonized by mycorrhizae, the ability of mycorrhizal fungi to decompose organic matter and influence the decomposition rate through competition with saprotrophic organisms. Keywords: mycorrhizal fungi, roots, decomposition, rate, organic matter, soil, importance, carbon sequestration
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Microbial communities and carbon cycling in subglacial ecosystems and their analogues
Rybár, Marek ; Stibal, Marek (advisor) ; Řeháková, Klára (referee)
Subglacial environments are located at the interface of glacier ice and bedrock. They represent one of the major ecosystems associated with glaciers and ice sheets. They contain liquid water and fine material including organic matter, accumulated during periods of glacier advance. It is well established that there are active microbial communities residing in these environments, which are adapted to living in extreme conditions. Subglacial ecosystems are mostly isolated from the atmosphere and thus their oxygen content is usually very low. Therefore, the organisms residing in these environments often employ anaerobic/anoxic strategies to ensure their survival. However, knowledge of these communities is limited due to practical constrains associated with subglacial ecology and biogeochemistry research. The activity of microorganisms beneath glaciers significantly influences carbon cycling. In recent years, this ecosystem is dynamically changing and may have important impact on regional and global carbon cycle. Therefore, it is important to better understand this ecosystem. This thesis summarizes recent knowledge of microbial communities and carbon cycling in this ecosystem and discusses suitable analogues, which could help us understand the fascinating subglacial ecosystem and formulate future research...
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Biotic interaction and their role in organic matter turnover in soil
Radochová, Petra ; Frouz, Jan (advisor) ; Smrž, Jaroslav (referee)
The thesis brings overview of main taxa of soil organisms. It describes in detail their trophic and non trophic interactions that contribute to organic matter decomposition in soil. In particular soil food web and behavior of fungal and bacterial channel of food web is described in relation to organic matter decomposition, soil formation and humus formation. This work contains also experimental work sealing with interaction of soil microscopic fungi and invertebrates. Food preference and suitability for development of three fungal species growing on three different litter types was studied. Litter was more important for food preference and food suitability. There were disproportion between litter suitability and litter preference. In particular oak was not preferred by adults but very suitable for development.
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Stability of humic substances
Nováková, Šárka ; Smilková, Marcela (referee) ; Klučáková, Martina (advisor)
This bachelor´s thesis is focused on the study of stability of humic acid. Thesis is divided in two parts, the first part is theoretical. In the theoretical part is dealing with the structure, property and point of humic acid and in the experimental part is dealing with stability of humic acid. The objective of this thesis was to investigate the effect of the extraction agents on stability of humic acid. 1M HCl, 1M MgCl2 and MiliQ water was used like extraction agents. Thermo-oxidative stability was tested trough thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Changes of humic acid that occured after extraction were investigated by FT-IR spektrometry and elementary analysis. The results of the measuring were compared with original humic acid.
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Phosphorus forms in river sediments
Schrimpelová, Kateřina ; Hrich, Karel (referee) ; Malá, Jitka (advisor)
Two main mechanism of immobilization of phosphorus in sediments are formation of insoluble phosphates of Ca, Mg, Fe, Al, and sorption. Phosphorus can be also immobilized as organic phosphorus contained in the biomass. This thesis is focused on searching of relationships between total, organic and inorganic phosphorus and iron, calcium and organic matter content in fluvial sediments. Within the framework of this thesis, samples of sediments have been collected and analyzed. The measured values have been filled by the data measured at the Institute of Chemistry in the years 2011-2012. Total number of samples is 48. Data have been statistically analyzed by Student’s t-test at the = 0,05 and = 0,01 levels of significance. The relationships between total phosphorus and iron and organic matter have been proven. Also the relationship between organic phosphorus and organic matter content has been proven and surprisingly the correlation with iron, too. The inorganic phosphorus indicated significant relationship with iron, but no significant relationship with the calcium content. At last there has been proven the correlation between inorganic phosphorus and the organic matter content.
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In situ ruminal degradation of organic matter of Trifolium pratense L.
KOUKOL, Ondřej
Seven clover sampes (Trifolium pratense L.) were collected at three different miters I (n = 3), II (n = 3) and III (n = 1) during the growing season from 10th of May to 17th of August. The samples were analyzed for chemical composition, gross energy (BE) content, in vivo sheep digestibility of organic matter (KS OH) and gross energy (KS BE) and in situ rumen degradability of organic matter and neutral detergent fibre (NDF). The contents of ash, crude protein (NL), crude fibre (CF), NDF, acid detergent fibre (ADF), acid detergent lignin (ADL) and BE were significantly (P < 0,05) affected by the date of cutting time. The averaged values were for ash 119,2 g/kg of dry matter, NL 197,7 g/kg of dry matter, CF 214,1 g/kg of dry matter, NDF 400,7 g/kg of dry matter, ADF 296,2 g/kg of dry matter, ADL 73,8 g/kg of dry matter and BE 18,2 MJ/kg of dry matter. KS OH and KS BE generally decreased with higher dates of cutting time. On average KS OH and KS BE amounted 72,4 % and 70,2 %, respectively. The effective ruminal degradability of organic matter (EDOH) was in average 81,7 % for miter I, 79,7 % for miter II and 75,2 % for miter III. In situ organic matter degradability characteristics were in average 41,9 % for the immediately degradable (soluble) fraction (parameter a), 47,1 % for the potential degradable fraction (parameter b) and 0,105 h-1 for the fractional rate of degradation (parameter c). The effective ruminal degradability of NDF (EDNDF) also generally decreased (P < 0,05) with increasing date of cutting time with values of 63,0 % for miter I, 59,7 % for miter II and 51,6 % for miter III. Strong correlation (P < 0,05) was observed between the EDOH and EDNDF (r = 0,979).
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