National Repository of Grey Literature 22 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Palaeoenvironmental reconstruction of the Younger Dryas based on fossil chironomids
Skurčáková, Anežka ; Tátosová, Jolana (advisor) ; Bitušík, Peter (referee)
The final stadial of the last glacial - Younger Dryas (12 650 - 11 500 cal yr BP) is relatively well described in sediments of European lakes, however research related to its progress in Central European area is missing. The goal of this thesis was to examine progress of this stadial based on sediment core from Černé Lake at Šumava (Czech Republic). To reconstruct climatic conditions, sub-fossil remains of Chironomidae was used. The air July temperature was estimated using Swiss-Norwegian model. Geochemical analysis was performed to determine intensity of erosion, trophic status of the lake, and sources of its organic matter. To complete information about catchment, pollen analysis was performed. Following climatic events were identified in the sediment: Older Dryas (13 583 - 13 394 cal yr BP), Alleröd (13 394 - 12 383 cal yr BP), Younger Dryas (12 383 - 11 394 cal yr BP) a Early Holocene (11 394 - 11 138 cal yr BP). Presence of two phases of Younger Dryas was not significantly proven, nevertheless, the isotope composition suggests, that the first half of this oscillation was drier. Reconstructed temperature ranged between 8,30 and 10,31řC. The mean temperature for Older Dryas event was 8,92 řC, for Alleröd 9,61 řC, Younger Dryas 9,17 řC and Early Holocene 10,00 řC. Reconstructed temperature...
Subfossil Cladocera as a powerful tool for paleoecological reconstruction
Bubenková, Anna ; Tátosová, Jolana (advisor) ; Kopalová, Kateřina (referee)
This bachelor thesis is a literature review documenting the usage of subfossil Cladocera in paleoecological reconstruction. Its aim is to argue for subfossil Cladocera as an effective means of studying historical evolution of lakes and identifying significant processes which formed them over time. Furthemore, this literature review critically evaluates some of the most common approaches to reconstructing changes in climate, water levels, acidification, and eutrophication, and numerous issues they often encouter. The correct interpretation is vital because all the factors in the aquatic environment are connected. Despite some debate, subfossil Cladocera are an important aspect of paleoecological reconstructions with much possible utilization in future research. Key words: subfossil Cladocera, paleoecology, reconstruction
Recent and subfossil chironomids as a tool for tracing of environmental changes in mountain lakes of glacial origin
Tátosová, Jolana ; Stuchlík, Evžen (advisor) ; Šporka, Ferdinand (referee) ; Brabec, Karel (referee)
JOLANA TÁTOSOVÁ, Charles University in Prague Ph.D. Thesis, 2008 ____________________________________________________________________________________ Summary Chironomid seasonality in a high mountain lake ecosystem - case study This paper summarizes result of the first complete round-year study of chironomids in the profundal zone of an oligotrophic high mountain Tatra lake - Ľadové lake - chosen as the key site in the EMERGE project. High mountain or arctic lakes are typical by the specific chironomid species composition, low species diversity at all and low abundances as well (Bretschko, 1974, Rieradevall & Prat, 1999, Aagaard, 1986, Brundin, 1956, Steinböck, 1955) Four chironomid taxa identified in the profundal of Ľadové lake (after average abundances) - Micropsectra radialis (Goetghebuer, 1939), Pseudodiamesa nivosa (Goetghebuer, 1928), Procladius (Holotanypus) sp. and Heterotrisscladius marcidus (Walker, 1856) - and the average chironomid density of 1 700 ind m-2 have confirmed this fact. The two most abundant taxa P. nivosa and M. radialis have demonstrated a univoltine life history with emergences in July and in August, respectively. According to published data, the univolitne life cycle of chironomids is expectable in high mountain or subarctic lakes (Moore, 1979, Wiederholm, 1977, Pechlaner et...
Identification and synchronization of YD period from Eruopaen lake sediments
Skurčáková, Anežka ; Tátosová, Jolana (advisor) ; Sacherová, Veronika (referee)
The bachelor thesis is the rewiew based on paleolimnological determining of Younger Dryas (YD), the final cold episode of the Last Glacial, and its diferent progress in European regions. It contains a describsion and an evaluation of methods of the YD identification (oxygen izotopes 18 O, varve chronology, radiocarbon dating, analysis of diatoms, pollen, chironomids, insect and geochemical and sedimentological analysis). The summary of results of studies from different parts of Europe showed that the first half of the YD in Western Europe was cooler and wetter than the second one. The climate during the YD period had similar temperature profile in Eastern Europe, but humidity had a different trend (the first half was colder and drier while the second one was warmer and wetter. According to the study of lake Švarcenberk in the Czech Republic, the YD had similar phases like in Western Europe. The YD period was synchronous in the most of Europe, its duration was approximately 1,200 years (12 726 - 11 564 years BP). Keywords: Younger Dryas, paleolimnology, oxygen izotopes, radiocarbon dating, varve chronology, climate in Europe
Diversity, distribution and ecology of epigeous amphipods in the Czech Republic
Hrdinová, Monika ; Sacherová, Veronika (advisor) ; Tátosová, Jolana (referee)
Amphipods (Crustacea, Amphipoda) can be found in fresh and brackish waters and in oceans and seas, several species live in terrestrial habitats. In comparison with other Central European countries there are fewer species of amphipods in the Czech Republic, their number, however, increased over the last decade from 8 to 12 species. Despite that, there is no recent review on ecology and distribution of those species. Presented study is an overview of epigeous species presently occurring in the Czech Republic, their ecology and habitat preferences, deals with changes in distribution areas and factors governing these changes. Based on specific features of species, it can be concluded that for expansion of distribution range a tolerance to extreme temperature peaks is needed, important is also availability of suitable habitats.
Palaeoecological reconstruction of Komořany Lake in Late Glacial based on diatom analysis
Poštulková, Anna ; Nedbalová, Linda (advisor) ; Tátosová, Jolana (referee)
Diatom analysis of basal part of profile PK-1-L contributes to multi-proxy research of former Lake Komořany. At this part of profile radiocarbon dating (dates sediments into Late Glacial and Early Holocene) and LOI (loss on ignition) had been conducted before, of which results have been utilized to more accurate interpretation of diatom analysis conclusions. Apart from diatom valves, presence of stomatocysts of Chrysophyceae has been observed. Having separated diatom valves from 32 sediment samples in intervals 0,4-0,6 cm, permanent preparates have been created. Concentration of valves in a gramme of dry sediment and relative abundance of diatom taxons in each sample have been investigated using light microscopy. In a half of samples subdominants and rare taxons have been observed separately to eliminate the interference from dominant taxons. Cluster analysis based on relative abundances of diatom taxons have been calculated and on its results have been subsequently determined three diatom accumulation zones (DAZ). Moreover trophic and saprobic indices have been calculated and levels of pH, conductivity and concentration of total phosphorus (TP) have been estimated by transfer functions. Even before beginning of Holocene the major shift in composition of diatom communities have happened, to the...
Arctic lakes: present zooplankton, subfossil record and past development reconstruction, focused on Svalbard
Sejbalová, Zuzana ; Sacherová, Veronika (advisor) ; Tátosová, Jolana (referee)
Arctic areas have low energy income and therefore harbour very simple food webs. Every environmental change has large and immediate impact. There are many types of lakes in the Arctic, and their sediments accumulate pieces of organisms that inhabited them. Most frequently those are Chironomidae, Diatomeae and Cladocera. My thesis is focused on Cladocera, which have very good subfossil record, most offen carapaces, head shields, postabdomens and ephippia can be found. In palaeolimnological studies these records are used to reconstruct development of environmental factors such as temperature, water level and trophic status. These models can then be used to predict future changes of the environment. My future work will be focused on lake Garmaksla in the central Svalbard and therefore all aspect in presented thesis is focused on Svalbard. Powered by TCPDF (www.tcpdf.org)
What is the key factor driving the expansion of invasive bentic invertebrates in the czech rivers?
Kolářová, Lucie ; Tátosová, Jolana (advisor) ; Sacherová, Veronika (referee)
The main part of the thesis discusses the occurrence and spreading of non - indigenous species of bentic freshwater invertebrates in the Labe River and it is based on long - term physical, chemical and biological data provided by Povodí Labe, state enterprise. Our results show a decrease in the concentration of nutrients at monitored stretch of the Labe River during the time period between years 2000 and 2011. The relative richness of non - indigenous species in benthic communities was analysed by TCI (Taxonomical Contamination Index), while their relative abundance was analysed by ACI (Abundance Contamination Index). Values of those two indexes increased during the time period between years 1998 and 2012. A detailed analysis is focused on four species - Dikerogammarus villosus, Corbicula fluminea, Jaera istri and Corophium curvispinum. The highest ACI value, as well as the total abundance of D. villosus, C, fluminea and J. istri, has been found at the Velké Březno site. Different values of TCI and ACI indexes and different abundances of specific invasive species can be caused by diverse environmental conditions characterising the studied sites. Significant differences between physical - chemical parameters measured at specific sites has been shown by the Kruskal - Wallis test (α = 0, 05). Only the...

National Repository of Grey Literature : 22 records found   1 - 10nextend  jump to record:
Interested in being notified about new results for this query?
Subscribe to the RSS feed.