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Molecular variability and distribution of the Frustulia rhomboides species complex (Bacillariophyceae)
Urbánková, Pavla ; Kulichová, Jana (advisor) ; Bešta, Tomáš (referee)
Recent use of molecular methods to revisit taxonomically problematic diatom species revealed severe limitations of morphological species concept. Characterization of diatom species which was based solely on the morphology of their frustules often generated too broad species boundaries which inevitably lead to wrong conclusions about their ecology and distribution. Widespread opinion that many diatom species are cosmopolitan generalists resulted in a theory that dispersal of diatoms is not limited by geographical distance. However, a number of recent studies showed that dispersal of diatoms is governed by the same rules which matter for macroorganisms. Proposed master thesis addresses the topic of diversity and dispersal in diatom species complex Frustulia rhomboides sensu lato in Europe and New Zealand. Results suggest that: (1) although revealed molecular variability in this complex shows clear ecological and biogeographical signal, it is not correlated in morphology. This is another support to general need for adoption of different species concept in diatoms. (2) A considerably uneven ratio in species diversity of genus Frustulia found in ecological similar habitats in Europe and New Zealand supports the idea that diatom dispersal is limited and stressed the need for studies dealing with biogeography.
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Geometric morphometrics of diatom frustules.
Hubáčková, Kateřina ; Kulichová, Jana (advisor) ; Pichrtová, Martina (referee)
This bachelor thesis includes a theoretical and a practical part. In the theoretical part, I focused problematic parts of research of diatoms biology. I will discuss morphology of specific silica scale and its morphogenesis; life cycle, characteristic by the size diminution in vegetative phasis, and conception of taxonomy of these organisms which is rather complicated because of unclear species concept. Another part presents tools of geometric morphometrics which is rapidly developing method for investigation and quantification of biological shape. In the practical part, I present the results from own research. This experiment is preliminary study for diploma thesis and its purpose is to appropriate tools of geometric morphometrics and to present advantages of its methods. I will investigate morphological disparity of three strains of pennate diatoms cultivated in standard conditions studied by landmark methos. The aim of this study is to discover if small cells which have gone trough the long phasis of vegetative multiplication and are close to the sexual reproduction have diferent degree of morphological variability than the bigger ones just undergone by sexual process.
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Diversity and relative biovolume of benthic diatom assemblages in relation to environmental conditions.
Šoljaková, Tereza ; Kulichová, Jana (advisor) ; Chattová, Barbora (referee)
iv ABSTRACT Benthic diatoms are due to a number of positive characteristics (such as high abundances, diversified communities, sensitive responses to environmental conditions, capturing long-term changes in the environmental conditions) currently the most commonly used bioindicators of the ecological status of freshwater ecosystems. However, due to problems associated with the use of traditional methods based on species composition (time-consuming identification, presence of species complexes, and requirements for calibration of water quality indexes for geographical regions) searching for alternative methods has been induced. The monitoring of the size structure of diverse diatom communities has been proposed as one of the methods. This approach would mainly eliminate the necessity of time-consuming determination of species. The main purpose of this thesis was therefore to determine the relationship between the size structure of benthic diatom communities, expressed as the relative biovolume, and selected environmental factors (pH, conductivity, habitat type) within freshwater lentic habitats. Furthermore, the variability of biovolume in dependence on environmental variables was compared with the change in species composition. If there would be a similar response pattern of both the biovolume and species...
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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...
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Diatoms of Quaternary Sediments from the Lake Komorany
Poštulková, Anna ; Rajdlová, Hana (advisor) ; Houfková, Petra (referee)
Diatoms are unicellular phototrophic organisms, whose siliceous frustules preserved in sediment have broad palaeolimnological application. Sediments of former Komořany Lake count among the richest Czech sediments in quaternary diatoms. This already destroyed locality is examinated in search and practical part of work. The search part contains characterization of diatoms and locality Komořany Lake. Diatoms are described in paleontological point of view, that is why the main attention is payed to morfology of frustule, their ecology and application in geological sciences. However, for complete image of this various group, the new pieces of knowledge about their taxonomy or evolution are not overlooked. The root of the work is summarization of accessible literature about Komořany Lake with special attention to research of diatoms. In practical part diatom valves were isolated from samples of sediment from profile PK-1-W, 18 long-lived sections were prepared and 6 of them were used for taxonomical determination. The 47 taxons of diatoms were found, 7 of them had not been included in work of Řeháková (1986). The synonymy of taxons are created in comparison with results of Řeháková (1986). From taken pictures are created 6 taxonomical plates. Key words: diatoms, Bacillariophyceae, Komořany Lake,...
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Diversity and relative biovolume of benthic diatom assemblages in relation to environmental conditions.
Šoljaková, Tereza ; Kulichová, Jana (advisor) ; Chattová, Barbora (referee)
iv ABSTRACT Benthic diatoms are due to a number of positive characteristics (such as high abundances, diversified communities, sensitive responses to environmental conditions, capturing long-term changes in the environmental conditions) currently the most commonly used bioindicators of the ecological status of freshwater ecosystems. However, due to problems associated with the use of traditional methods based on species composition (time-consuming identification, presence of species complexes, and requirements for calibration of water quality indexes for geographical regions) searching for alternative methods has been induced. The monitoring of the size structure of diverse diatom communities has been proposed as one of the methods. This approach would mainly eliminate the necessity of time-consuming determination of species. The main purpose of this thesis was therefore to determine the relationship between the size structure of benthic diatom communities, expressed as the relative biovolume, and selected environmental factors (pH, conductivity, habitat type) within freshwater lentic habitats. Furthermore, the variability of biovolume in dependence on environmental variables was compared with the change in species composition. If there would be a similar response pattern of both the biovolume and species...
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An ecological perspective on diatom morphology.
Fialová, Markéta ; Kulichová, Jana (advisor) ; Hodač, Ladislav (referee)
A traditional species concept of diatoms is based on morphological characters of their siliceous boxes. A multidisciplinary approach to defining species of diatoms has revealed the hidden diversity within the traditionally defined species. But the newly recognized species are morphological variable and indistinguishable by the naked eye. Recent studies showed that different morphotypes show different ecological preferences. This master thesis focuses on the morphology of natural populations of the diatom species complex Frustulia rhomboides which contains both the traditional and the cryptic species, and it engages how the morphology reflects the effects of environmental conditions. Landmark methods of geometric morphometrics were used in order to analyze the morphological variability of diatom frustules of this species complex within various peat bog habitats in the Czech Republic. Selected environmental parameters were measured and the species composition of diatom communities present in the samples was investigated. These data were used to analyze the relationship between the environmental conditions and the cell shape variability within the complex. The analysis revealed the main trends of morphological variability related to different environmental conditions. Two morphotypes characteristic...
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Geometric morphometrics of diatom frustules.
Hubáčková, Kateřina ; Kulichová, Jana (advisor) ; Pichrtová, Martina (referee)
This bachelor thesis includes a theoretical and a practical part. In the theoretical part, I focused problematic parts of research of diatoms biology. I will discuss morphology of specific silica scale and its morphogenesis; life cycle, characteristic by the size diminution in vegetative phasis, and conception of taxonomy of these organisms which is rather complicated because of unclear species concept. Another part presents tools of geometric morphometrics which is rapidly developing method for investigation and quantification of biological shape. In the practical part, I present the results from own research. This experiment is preliminary study for diploma thesis and its purpose is to appropriate tools of geometric morphometrics and to present advantages of its methods. I will investigate morphological disparity of three strains of pennate diatoms cultivated in standard conditions studied by landmark methos. The aim of this study is to discover if small cells which have gone trough the long phasis of vegetative multiplication and are close to the sexual reproduction have diferent degree of morphological variability than the bigger ones just undergone by sexual process.
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Molecular variability and distribution of the Frustulia rhomboides species complex (Bacillariophyceae)
Urbánková, Pavla ; Kulichová, Jana (advisor) ; Bešta, Tomáš (referee)
Recent use of molecular methods to revisit taxonomically problematic diatom species revealed severe limitations of morphological species concept. Characterization of diatom species which was based solely on the morphology of their frustules often generated too broad species boundaries which inevitably lead to wrong conclusions about their ecology and distribution. Widespread opinion that many diatom species are cosmopolitan generalists resulted in a theory that dispersal of diatoms is not limited by geographical distance. However, a number of recent studies showed that dispersal of diatoms is governed by the same rules which matter for macroorganisms. Proposed master thesis addresses the topic of diversity and dispersal in diatom species complex Frustulia rhomboides sensu lato in Europe and New Zealand. Results suggest that: (1) although revealed molecular variability in this complex shows clear ecological and biogeographical signal, it is not correlated in morphology. This is another support to general need for adoption of different species concept in diatoms. (2) A considerably uneven ratio in species diversity of genus Frustulia found in ecological similar habitats in Europe and New Zealand supports the idea that diatom dispersal is limited and stressed the need for studies dealing with biogeography.
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