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Dispersal mechanisms in freshwater algae and cyanobacteria
Hejduková, Eva ; Nedbalová, Linda (advisor) ; Pichrtová, Martina (referee)
Global occurrence of many species of freshwater cyanobacteria and algae shows, that they are dispersed easily. However, the exact transport mechanisms are not known for most of these microorganisms. This bachelor thesis introduces various mechanisms that could be responsible for the dispersal of freshwater cyanobacteria and algae. It includes information about four main methods of transport, which is dispersal by water (hydrochory), transport through atmospheric circulation and wind (anemochory), dispersal by animals (zoochory) and by human (anthropochory), who is recently also involved in the transportation of freshwater cyanobacteria and algae. The thesis also summarizes adaptation mechanisms that enable cyanobacteria and algae to colonize new habitats successfully, and discusses possible implications of the dispersal ability for the distribution of microorganisms. Currently there are two contradictory views - cosmopolitan distribution and the occurrence of endemic species. Despite their importance the dispersal mechanisms of freshwater cyanobacteria and algae are less-studied than it might seem at first sight. Key words: freshwater algae, cyanobacteria, dispersal mechanisms, spores, cysts, distribution of microorganisms, hydrochory, anemochory, zoochory, anthropochory
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Extreme abiotic conditions as determinants of phytoplankton structure in high mountain lakes
Mihál, Martin ; Nedbalová, Linda (advisor) ; Hořická, Zuzana (referee)
There are many areas with extreme environmental conditions in the world. One of them are high mountain lakes which are located above treeline. Bachelor thesis presents the main abiotic conditions as determinants of phytoplankton structure in high mountain lakes. It has to cope with significant changes in light conditions and high intensity of sunlight during ice-free periods and with an important diminution of radiation by snow and ice cover. The thesis also discusses the influence of temperature, which is related to the duration of the ice and snow cover and a stratification of lakes. It characterizes local factors, such as topographic shading, morphology of lakes and character of basins, which affect chemical and physical properties of lakes. The thesis also mentions the impact of atmospheric deposition and other factors on nutrient concentrations in the water column. In addition, it discusses the adaptations of phytoplankton to environmental conditions, which include development of deep chlorophyll maximum, biosynthesis of protective compounds and nutrition strategy (mixotrophy). The thesis shows that there are many specific abiotic factors, which influence phytoplankton in high mountain lakes and all these factors interact. This results in a characteristic species composition with prevalence of...
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Cold adaptation mechanisms in microorganisms
Dřízhalová, Marie ; Nedbalová, Linda (advisor) ; Kvíderová, Jana (referee)
On our planet there are vast areas, where the average temperature does not exceed 5 řC. They are also many places, where the temperature often drops below zero. Not every living organism is able to live in these conditions. The ability to survive in cold region and succefully colonize, such presumably adverse environment requires particular evolutionary adaptation. Adaptation to cold environments has evolved independently in different phylogenetic groups. In low temperature environments, organisms has to adapt in a complex way to be able to permanently inhabit these habitats. Since the analysis of cold adaptation in all organisms is a very complex topic, this thesis is focused on microorganisms. Within this group, it is possible to find certain, which are repeated also in unrelated taxa. The general mechanisms include changes in membrane composition, shifts of enzyme temperature optima, production of compounds that prevent the negative effects of low temperature or the formation of resting stages. This thesis summarizes the mechanisms of cold adaptation which have evolved in microorganisms as response to a long-term or temporary survival at low temperatures. Their potential biotechnological applications are also mentioned. keywords: psychrophilic, psychrotolerant, cold adaptation, enzymes,...
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Iron fertilization of the Southern ocean
Přibylová, Petra ; Koblížek, Michal (advisor) ; Nedbalová, Linda (referee)
This thesis summarizes the current knowledge of the effect of iron on the growth of plankton in relation to lowering the concentration of CO2 in the atmosphere. Iron is a limiting factor for phytoplankton growth in large parts of the Pacific Ocean and the Southern Ocean. This thesis is focused on the Southern ocean, where it chronologically describes natural and artificial experiments, where the objective was to uncover the possibilities of artificial iron fertilization of the ocean. The iron fertilization experiments were based on supplying the upper layer of the ocean with an iron solution, which resulted in an increase in phytoplankton growth and chlorophyll concentration. The reaction of plankton to a natural iron input via upwelling was also observed. In these cases an increase of phytoplankton and chlorophyll was observed. Nowadays, the lively discussed possibility of large-scale fertilization is restricted by the United Nations due to insufficient knowledge and concerns of geoengineering.
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Diet quality impact on growth and survival of freshwater zooplankton species
Sýkorová, Veronika ; Sacherová, Veronika (advisor) ; Nedbalová, Linda (referee)
Food quality has a significant influence on freshwater zooplankon. It influences its growth rate and development generally. By quality we understand a certain stoichiometric ratio of the main biogenic elements (carbon, nitrogen, phosphorus) in the biomass of food. Ecological stechiometry is helping to understand the balance of chemical elements in ecological interactions and processes. Freshwater zooplankton consists mostly of two groups of organisms: rotifers (Rotifera) and crustaceans (Crustacea) - cladocerans (Cladocera) and copepods (Copepoda). Each of this groups requires different quality of food. Most of filtering cladocerans are fast- growing organisms, which need a phosphorus-rich food for their fast development (small C:P ratio in food) and vice versa for most of the copepods. The food offered is not always ideal for all members of zooplankton, that is why various pre- and post- absorptional mechanisms developed to help them to cope with unsuitable food. The ability to survive unvafourable conditions is closely linked to the zoolpankton's reactions to unsuitable C:N:P ratio in its food. The C:N:P ratio in food of zooplankton also influences the species distribution in water bodies. Key words: stoichiometry, food quality, zooplankton
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Phytoplankton in experimental ponds: colonization and seasonal succession
Hrušková, Lenka ; Nedbalová, Linda (advisor) ; Lukavský, Jaromír (referee)
Artificial ponds are excellent for the study of phytoplankton ecology. They permit repeatable initial conditions and sufficient replication of independent experimental units in complex experiments to test hypotheses about the control of structure and function in natural communities. There were 20 experimental ponds constructed in Kokoř nsko Protected Landscape Area, from which samples were taken and analyzed. This study was part of the EU BIOPOOL. During the first two years after the filling of the ponds the colonization and the seasonal development of phytoplankton communities in the ponds were examined. The phytoplankton species composition was determined, then species richness and relative abundance of individual taxa were quantified. Species composition data were compared with the environmental parameters measured (temperature, oxygen concentration, pH, transparency, conductivity, depth, chlorophyll-a concentration, and zooplankton). In the spring 2007, the ponds were periodic, and followed a similar trend over time (February- April). There were dominated by the following taxonomic groups: Dinophyta, Chrysophyta, Cryptophyta, and Euglenophyta. After installing foil on the bottom of the ponds, the ponds were of permanent character. In terms of environmental parameters, the individual ponds...
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Phytoplankton of the Tatra lakes: factors influencing taxonomic composition and biomass
Červenková, Lenka ; Nedbalová, Linda (advisor) ; Štefková, Elena (referee)
The aim of this diploma thesis was to describe species composition and biomass of phytoplankton in the Tatra Mountains lakes (Slovakia, Poland) and environmental factors influencing them. The surface layer of 89 lakes was sampled in September 2004. Flagellates from Chrysophyta, Dinophyta and Cryptophyta most frequently dominated the phytoplankton biomass. Lake in the same valley usually differed in their dominant taxonomic group as a result of different lake morphometry, catchment type and detailed geological structure. Based on the level of phytoplankton biovolume, the majority of lakes were ultraoligotrophic and oligotrophic, however, mesotrophic and even eutrophic conditions were recorded in some forest and meadow lakes. An allometric relationship between phytoplankton biomass and chlorophyll a was revealed. Specific chlorophyll content did not differ among taxonomic groups. Altogether 233 species were determined, the most diverse group were Chlorophyta. Species richness of lake was 3-46 and it was negatively correlated with altitude and positively correlated with lake area. The majority of species were rare both in term of biomass and number of lakes occupied by a particular species. Average local species biomass was positively correlated with regional distribution. The similarity of species...
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Phytoplankton in acidified lakes: structure, function and response to ecosystem recovery
Nedbalová, Linda
This thesis is based on five publications dealing with plankton assemblages of lakes in two heavily acidified mountain areas in Central Europe, the Bohemian Forest and the High Tatra Mountains. As both lake districts are the object of long term systematic ecological research, a unique set of complex limnological data was gathered, enabling a comparison with other affected regions throughout the world and also some attempts at generalisation. My role in the team consisted chiefly in the study of phytoplankton as the key component of the food web. I was mainly concerned with the structure, seasonal development and function of the phytoplankton assemblages, and I also focused on the evaluation of general biological response to the current chemical recovery of the lakes from acidification. The main questions addressed in this thesis with an emphasis on phytoplankton assemblages are the following: What is the recent progress in chemical and biological recovery of the Bohemian Forest lakes from acidification? What are the key factors and mechanisms influencing species composition and structure of plankton biomass in the Bohemian Forest lakes? What is the role of episodic acidification in shaping both phytoplankton abundance and biomass in a non acidified high mountain seepage lake (Ľadové Lake, High Tatra...
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