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Simulation of Snow and Ice Features
Čech, Ondřej ; Polášek, Tomáš (referee) ; Čadík, Martin (advisor)
This project focuses on simulation of formation of glaciers known as Penitentes. It is based on mathematical model of formation of these structures by M. D. Betterton. Implementation is done in C++ programming language, and the result is exported as bitmap image containing heightmap, which can be rendered using Blender.
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Teplotní adaptace trávicích enzymů želvušek žijících v trvale chladném prostředí
JOZIĆ, Nikola
This thesis presents a literature review of the phylum Tardigrada, exploring the impact of cold temperatures on living organisms in general and focusing on adaptations of organisms to cold and freezing, particularly in terms of enzymatic adaptations. The experimental part of this work involves comparing the enzymatic activity of the -glucosidase enzyme in tardigrades from Arctic glacier (Svalbard) and soil tardigrades from a temperate climate (Czech Republic) at different temperatures. The results showed higher enzymatic activity in tardigrades from a temperate climate at all measured temperatures, suggesting that the enzymes of glacier dwelling tardigrades are not cold adapted.
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Origin and evolution of proglacial lakes in the Patagonian Andes
Danišová, Dominika ; Vilímek, Vít (advisor) ; Šobr, Miroslav (referee)
Origin and evolution of proglacial lakes in the Patagonian Andes ABSTRACT: Proglacial lakes are dynamic water bodies affected by the evolution of glacier ice masses, morphology and climatic factors. Mountain glaciers are very sensitive to climate change, which has caused their continuous recession recent decades. Glacier retreat is closely linked to an increase in the volume of proglacial lakes, especially in high mountain areas. The growth of proglacial lakes can also lead to increased probability of overtopping or dam rupture, also known as GLOF. The first aims of the presented thesis are to describe how proglacial lakes are formed, what factors can influence their continuous evolution and, lastly, how the lakes can affect their surroundings. In order to perform the spatial and temporary analysis, an inventory of the proglacial lakes in the North Patagonian Icefield was made, as this area has not yet been properly studied. In the time scale from 1984 till now, 640 lakes were characterised. The results show that along with glacier retreat, proglacial lakes are increasing in both size and number. However, the correlation with the climatic data is limited because of its poor quality and inadequate distribution in this area. Keywords: glacial lakes, glaciers, lake-dams, North Patagonian Icefield, GLOF
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Simulation and Visualization of Snow and Ice Features
Čech, Ondřej ; Polášek, Tomáš (referee) ; Čadík, Martin (advisor)
The topic of this thesis is a simulation of the formation of ice features called penitentes. Penitentes are ice features formed by sublimation, that is caused by the concentration of solar energy in depressions of the snow surface. The model is based on the mathematical description by M. D. Betterton. Main highlight of this work is an extension of this one-dimensional model into three-dimensional space using ray casting and Monte Carlo integration. The final program works with Polygon File Format 3D objects and is written in C++ language. Its results were evaluated on synthetic data and also on a scan of the natural penitentes field. The model proved it can form structures visually similar to penitentes, but interaction with real data showed some problematic behavior transferred from the original mathematical model.
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Simulation of Snow and Ice Features
Čech, Ondřej ; Polášek, Tomáš (referee) ; Čadík, Martin (advisor)
This project focuses on simulation of formation of glaciers known as Penitentes. It is based on mathematical model of formation of these structures by M. D. Betterton. Implementation is done in C++ programming language, and the result is exported as bitmap image containing heightmap, which can be rendered using Blender.
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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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Origin and evolution of proglacial lakes in the Patagonian Andes
Danišová, Dominika ; Vilímek, Vít (advisor) ; Šobr, Miroslav (referee)
Origin and evolution of proglacial lakes in the Patagonian Andes ABSTRACT: Proglacial lakes are dynamic water bodies affected by the evolution of glacier ice masses, morphology and climatic factors. Mountain glaciers are very sensitive to climate change, which has caused their continuous recession recent decades. Glacier retreat is closely linked to an increase in the volume of proglacial lakes, especially in high mountain areas. The growth of proglacial lakes can also lead to increased probability of overtopping or dam rupture, also known as GLOF. The first aims of the presented thesis are to describe how proglacial lakes are formed, what factors can influence their continuous evolution and, lastly, how the lakes can affect their surroundings. In order to perform the spatial and temporary analysis, an inventory of the proglacial lakes in the North Patagonian Icefield was made, as this area has not yet been properly studied. In the time scale from 1984 till now, 640 lakes were characterised. The results show that along with glacier retreat, proglacial lakes are increasing in both size and number. However, the correlation with the climatic data is limited because of its poor quality and inadequate distribution in this area. Keywords: glacial lakes, glaciers, lake-dams, North Patagonian Icefield, GLOF
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The analysis of supraglacial lakes: case study from Cordillera Blanca, Peru
Baťka, Jan ; Vilímek, Vít (advisor) ; Emmer, Adam (referee)
The analysis of supraglacial lakes: case study from the Cordillera Blanca, Peru ABSTRACT: Supraglacial lakes play an important role in the processes of glacier ablation. Through their expansion, a proglacial lake that usually poses significant threat to downvalley located areas can form. Such formation of proglacial lakes also took place and was well described in the Peruvian Cordillera Blanca (e.g. Laguna 513). However, there are only few studies relating to supraglacial lakes of this range. First in this thesis, based on the research of the scientific literature, the factors influencing supraglacial lakes' development and some of the limnological characteristics are listed in detail. Second, recent evolution (2003-2014) of supraglacial lakes of the Cordillera Blanca is analysed on the sample of 13 glaciers. The results show that the development of supraglacial lakes is influenced by their frequent destructions (because of outbursts and/or rapid accumulation of debris in the basin). In addition, the expansion of the extent of supraglacial lakes on a glacier tongue is strongly controlled by surface gradient. Keywords: glaciers, supraglacial lakes, Cordillera Blanca, Peru
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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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