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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
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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.
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Historical development of zooplankton of the Starolesnianske lake (the High Tatra Mountains, Slovakia) in the context of global changes
Blechová, Magdalena ; Hořická, Zuzana (advisor) ; Sacherová, Veronika (referee)
The aims of the thesis were to document the history of the Cladocera (Crustacea) community structure in the Starolesnianske Lake (the High Tatra Mountains, Slovakia) with regards to environmental changes (e. g., Medieval Warm Period, Little Ice Age, anthropogenic acidification, recovery from acidification), and to analyze in detail the development of zooplankton (Cladocera, Copepoda, Rotifera) during the peaking acidification and recovery from acidification (1978 - 2015). Based on results of both the approaches, the appropriateness of using historical data on zooplankton in Tatra lakes between 1909 - 1913 (Minkiewicz, 1914) as a reference condition for the evaluating biological recovery from acidification should have been assessed. The methods used were paleolimnological analyses of lake sediment (namely subfossil Cladocera), analysis of recent zooplankton, and analyses of lake water chemistry. It was found that in the historical record, relative abundances of Cladocera species significantly changed cca 150 years ago (at the end of the Little Ice Age and, in the main, in the period of anthropogenic acidification). The lake, though, has had a very stable species composition of Cladocera during the last cca 2,000 years, represented by four species: Alona quadrangularis, Alonella excisa, Ceriodaphnia...
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Crustaceans of Antarctic lakes - past and present status
Pokorný, Matěj ; Sacherová, Veronika (advisor) ; Nedbalová, Linda (referee)
Antarctic continent is one of the most severe regions on Earth and it is characterized by low annual temperatures, low precipitation, extensive ice cover and low energy input from the Sun. Nevertheless its lakes host not only microbial communities and protists but in many cases even in the most extreme localities also metazoans, especially rotifers and crustaceans. For at least the last 15 million years Antarctica has experienced massive glaciations that shape the distribution of organisms on this continent. Although it was originally thought that freshwater animals did not survive Quaternary glaciations in situ but migrated to milder regions in the north, nowadays it appears that at least in some cases it is not true. Direct evidence of survival of rotifers (Notholca sp.) and crustaceans (Daphniopsis studeri) in Antarctica was given by paleolimnological studies that were carried out in the Larsemann Hills and circumstantial evidence for permanent survival of crustaceans in Antarctica (e.g. Gladioferens antarcticus) is also growing. Antarctica is currently inhabited by about 14 species of freshwater crustaceans but recent climate changes and rapid warming of Antarctic Peninsula will probably lead to changes in the distribution of some species (e.g. Bockella poppei, Branchinecta gaini) that could, combined...
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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)
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Genetic structure and origin of Central European populations of tadpole shrimp Lepidurus apus (Crustacea: Notostraca)
Vopařilová, Lucie ; Sacherová, Veronika (advisor) ; Merta, Lukáš (referee)
Freshwater invertebrates especially species from temporary ponds are suitable model organisms for studying of dispersal mechanisms in their discontinous habitats. Tadpole shrimp Lepidurus apus (Notostraca) is restricted to vernal temporary waters in floodplain areas of big rivers. This Master's thesis is concentrated on survey of genetic variability and structure of L. apus population from Central Europe. Mitochondrial COI analysis of 45 specimens mostly from the Czech Republic indicates that all Central European specimens falls into the subspecies L. apus apus and also indicates low level of genetic variability and structure (on average 0,2 %). These results are confronted with other notostracan species, additionally with czech populations of coldstenothermal brine shrimp Eubranchipus grubii (Anostraca) and possible reasons of the low values are discussed.
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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...
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Foraging strategies of invertebrate predators in mountain lakes
Hrdličková, Jana ; Sacherová, Veronika (advisor) ; Hořická, Zuzana (referee)
In mountain lakes, which were affected by acidification in the past or in the present, invertebrate species have become top predators and they influence the whole community. This thesis deals with foraging strategies of three of these predators, Cyclops abyssorum and Heterocope saliens (Crustacea: Copepoda) and Glaenocorisa propinqua (Insecta: Heteroptera) in the model localities Černé lake, Plešné lake and Prášilské lake. The main aim was the determination of food composition and food preferences of these predators. The quality and quantity of consumed food I investigated with a microscope using a method which has not been published yet. To make a microscope preparation I used Potassium hydroxide or Lactic acid in order to dissolve soft organic matter, so that the chitinous particles were well visible. The found food of animal origin was subsequently compared with the prey availability with the use of Jacobs' index. In addition to this research, a feeding experiment with G. propinqua was carried out. The food of all the invertebrate predators was dependent on food availability or eventually on the season of the year. G. propinqua mostly preferred as a prey members of Daphniidae family and then the species Polyphemus pediculus (Cladocera), if they were available (Prášilské lake). In Plešné lake,...
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Phylogeography and dispersal routes of the Proasellus coxalis s.l. (Crustacea: Isopoda)
Koprnická, Markéta ; Sacherová, Veronika (advisor) ; Šanda, Radek (referee)
Dispersal of freshwater invertebrates is affected by many factors. Recently, human activities played a very important role in their dispersal. Among others, constructions of new shipping canals damages natural boundaries and the species can spread into new areas. This Master thesis deal with non-indigenous species P. coxalis s.l. On the genetic bases assess a possible dispersal routes into the Central Europe (and the Czech Republic), and phylogeography of this species in the Czech Republic. I amplified and sequenced DNA of the mitochondrial cytochrome oxidase subunit I (COI) gene and 28S nuclear rDNA gene. 96 individuals from 27 localities in the Czech Republic were analyzed. I also included 40 sequences of the COI gene and 7 of the 28S gene from the GenBank database. In the Czech Republic, there are two different genealogic lineages of P. coxalis (with 6% genetic distance between sequences of the COI gene). The first lineage comes from recent invasion of this species from Mediterranean area (through Western invasion corridor and other shipping canals). The second lineage is probably indigenous in the area and it can probably be assigned to the subspecies P. coxalis septentrionalis. The results are discussed. Keywords: Proasellus coxalis s.l., COI, dispersal routes, phylogeography
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Food quality impact on growth and survival of Daphnia longispina (Crustacea: Cladocera)
Sýkorová, Veronika ; Sacherová, Veronika (advisor) ; Macháček, Jiří (referee)
This thesis focuses on ecological processes among plankton organisms. It especially questions the influence of food quality on growth and survival of freshwater plankton. I focused on the influence of various ratios of nitrogen and phosphorus in available food. I am also interested in finding out the food requirements of chosen consumer Daphnia longispina. Within this broad topic, I specify a question, whether various quality and quantity of food influences the life history parameters of the species Daphnia longispina and whether the absence of common species of Cladoceran Daphnia longispina in Plešné Lake is caused by unsuitable quality of food. I have bred Daphnia longispina in laboratory conditions for two years. I fed it by algae Monoraphidium dybowskii isolated from Plešné Lake and grown in two media P-limited (C:P 1174), P-unlimited (C:P 290) and three concentration (1,2, 4 mg C/L). Cladocerans fed by food from medium that had a C:N:P ratio approximately the same as can be found in Plešné Lake (C:P 1174) lived for a singificantly shorter period of time and during the experiment they did not reproduce even in the case with the largest amount of food (4 mg C/L). This is a possible reason why Daphnia longispina did not return to Plešné Lake after the period of strong acidification, climax of...
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