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Natural archives of infilled lakes in the Třeboň Basin and the Bohemian Forest
Burda, Jan ; Vondrák, Daniel (advisor) ; Prach, Jindřich (referee)
In the territory of Czechia, lake sediments serve as invaluable natural archives, allowing us to study environmental changes in the Late Pleistocene and the Holocene. Understanding these changes is crucial for contextualizing various contemporary environmental issues and managing protected areas. Sediments from infilled lakes can also be used for research of past environmental change. The aim of this bachelor thesis is to summarize and compare the results of previous research on infilled lake sediments in the Třeboň Basin and the Bohemian Forest. Both areas contain basins with lake sediments dating back up to ca. 17,000 years. The thesis describes the principle of the formation of these lake basins, the regionally specific climate evolution, the evolution of soil and vegetation conditions in the lake catchments and the evolution of lake ecosystems. The history of the impact of human activities on the immediate surroundings of the lakes is also considered. So far, 32 infilled lakes have been found in the Třeboň basin and 3 infilled lakes in the Bohemian Forest. Another 9 lakes still exist in the Bohemian Forest. This review highlights the differences in the knowledge of the individual sites and the differences between the research carried out in the two areas. Keywords: lake sediments, Late Glacial,...
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Interpretation of carbon stable isotope data from lake sediment archives
Lánová, Zuzana ; Tátosová, Jolana (advisor) ; Jandová, Kateřina (referee)
Lake sediments consist of terrestric plant matter, lacustrine plancton primary production and microbial lake biomass. All of these organism groups discriminate during C-substate fixation and/or its further assimilation heavier and more stable 13 C carbon at a certain ratio, which is reflected by 13 C concentration in their biomass and consequently in sediments. The reason of discrimination at these enzymatically controlled biochemical reactions lies at kinetic fractionation controlled by binding energies of chemical substances. Isotopic signature contained in organic matter of lake sediments can be influenced by photosyntesis intensity, formation of anoxic zone allowing methanogenic a methanotrophic bacteries activity, lake trophic state or hydrologic isolation (long periods of drought). Keywords: Paleolimnology, carbon isotopes, discrimination processes, lake sediments
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Upper Pleistocene environmental dynamics in central Europe: multidisciplinary research of loess/paleosols sequences and lacustrine sediments
Hošek, Jan
The principal goal of this thesis was to provide relevant information on the spatiotemporal dynamics of erosion-sedimentation and weathering processes in the last climatic cycle and to interpret the obtained data in the context of European paleoenvironmental development. Representative sequences of loess, paleosols and lacustrine sediments from the area of the Bohemian Massif, the Carpathian Foredeep, the the Vienna Basin and the northern edge of the Panno-nian Basin were investigated using a wide range of instru-mental tools and paleontological methods. A uniform analytical approach applied to these sedimentary facies has provided ample new information about the paleoclimatolog-ical and paleoenvironmental development of East-Central Europe - an important region in the transition zone from oceanic to continental macro-climatic settings. The individu-al studies included in this PhD thesis cover the complete period of the Upper Pleistocene (MIS 5-2; ~130-12.7 ky BP) and are presented as separate chapters in the order of the superposition of strata. Chapters III/1-3 deal with the results of research into six loess/paleosol sequences (LPSs) situated in the Central Bohemian Massif, throughout the Moravian Valleys, and at the northwest and north edge of the Pannonian Basin. A detailed paleoenvironmental...
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Correlation of abiotic proxies in Holocene lacustrine sediments of Peri-Atlantic Arctic
Roman, Matěj ; Nývlt, Daniel (advisor) ; Sedláček, Jan (referee)
The peri-Atlantic Arctic, one of the most sensitive components of the Earth climate system, experienced pronounced climatic fluctuations during the Holocene. Several external forcings were considered responsible for these variations, including decline of insolation on the Northern Hemisphere, changes in distribution of land ice mass, explosive volcanism, or changes in atmospheric and oceanic circulation. In order to explore the driving mechanisms of the peri-Atlantic Arctic environmental variability, three sites located in different parts of the region were selected for palaeoenvironmental reconstructions with focus on extracting the climatic information. With this intention, sedimentary cores from i) Lake Garmaksla, Central Svalbard, ii) Jarfjorden, northeastern Norway, and iii) Kobbefjord area, southwestern Greenland, were retrieved and subjected to multi-proxy investigation. The absolute chronostratigraphic framework was established by comprehensive radiocarbon (14 C) and short-lived radioisotopes (210 Pb, 137 Cs) dating. Further analyses include measurements of magnetic susceptibility, grain size distribution, element composition by means of X-ray fluorescence (XRF), and elements bound to organic matter, i.e. organic carbon, nitrogen, sulphur and biogenic silica. The relationships between the...
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Upper Pleistocene environmental dynamics in central Europe: multidisciplinary research of loess/paleosols sequences and lacustrine sediments
Hošek, Jan
The principal goal of this thesis was to provide relevant information on the spatiotemporal dynamics of erosion-sedimentation and weathering processes in the last climatic cycle and to interpret the obtained data in the context of European paleoenvironmental development. Representative sequences of loess, paleosols and lacustrine sediments from the area of the Bohemian Massif, the Carpathian Foredeep, the the Vienna Basin and the northern edge of the Panno-nian Basin were investigated using a wide range of instru-mental tools and paleontological methods. A uniform analytical approach applied to these sedimentary facies has provided ample new information about the paleoclimatolog-ical and paleoenvironmental development of East-Central Europe - an important region in the transition zone from oceanic to continental macro-climatic settings. The individu-al studies included in this PhD thesis cover the complete period of the Upper Pleistocene (MIS 5-2; ~130-12.7 ky BP) and are presented as separate chapters in the order of the superposition of strata. Chapters III/1-3 deal with the results of research into six loess/paleosol sequences (LPSs) situated in the Central Bohemian Massif, throughout the Moravian Valleys, and at the northwest and north edge of the Pannonian Basin. A detailed paleoenvironmental...
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Upper Pleistocene environmental dynamics in central Europe: multidisciplinary research of loess/paleosols sequences and lacustrine sediments
Hošek, Jan ; Lisá, Lenka (advisor) ; Nývlt, Daniel (referee) ; Ložek, Vojen (referee)
The principal goal of this thesis was to provide relevant information on the spatiotemporal dynamics of erosion-sedimentation and weathering processes in the last climatic cycle and to interpret the obtained data in the context of European paleoenvironmental development. Representative sequences of loess, paleosols and lacustrine sediments from the area of the Bohemian Massif, the Carpathian Foredeep, the the Vienna Basin and the northern edge of the Panno-nian Basin were investigated using a wide range of instru-mental tools and paleontological methods. A uniform analytical approach applied to these sedimentary facies has provided ample new information about the paleoclimatolog-ical and paleoenvironmental development of East-Central Europe - an important region in the transition zone from oceanic to continental macro-climatic settings. The individu-al studies included in this PhD thesis cover the complete period of the Upper Pleistocene (MIS 5-2; ~130-12.7 ky BP) and are presented as separate chapters in the order of the superposition of strata. Chapters III/1-3 deal with the results of research into six loess/paleosol sequences (LPSs) situated in the Central Bohemian Massif, throughout the Moravian Valleys, and at the northwest and north edge of the Pannonian Basin. A detailed paleoenvironmental...
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Paleoenvironmental interpretation of elemental geochemical proxies of the borehole Jp 585: Lower Miocene lacustrine offshore clays of Cypris Formation, Sokolov Basin
Erlebachová, Alice ; Martínek, Karel (advisor) ; Opluštil, Stanislav (referee)
This thesis presents geochemical study of the Lower Miocene lacustrine offshore clays of the Cypris Formation in the Sokolov Basin of the Eger Graben aimed at paleoenvironmental reconstruction. The applicability of elemental geochemistry proxies in the interpretation of 94 m thick lithologically monotonous, offshore lacustrine clay succession of the well core Jp 585 is tested. Geochemical proxy data seems to be a good indicator of changes in source areas ,erosion rates and climate. XRF analysis shows for example decrease of detrital input and the increase in amount of authigenic silica and carbonates upwards in the section. The results of CEC analysis point to a rapid variations of expandable clay minerals content. Marked increase of CEC is at 40 m depth. Combination of XRF and CEC enabled suggesting of four chemostratigraphical units. Their boundaries are often sharp, pointing to rapid changes in lake metabolism. These changes are preliminary interpreted as climate changes.
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