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Study of the limnological components of the ecosytem of Lake Medard in 2022
Peterka, Jiří ; Hejzlar, Josef ; Nedoma, Jiří ; Znachor, Petr ; Seďa, Jaromír ; Vejřík, Lukáš
The report summarizes the results of research into the limnological and biological components of the ecosystem of the newly created Medard post-mining lake. The aim of the presented report is to summarize the results achieved for the year 2022 and recommendations for further monitoring. The year 2022 was the fifth year after the lake was completely filled, when water from the Ohře River was no longer added. Only small tributaries flowed into the lake from its own catchment area, and at the same time, water from the lake drained through seeps, which are apparently drained into the nearby rivers, the Ohře and the Svatava. The lake ecosystem reached the final state of its initial phase in terms of hydrological regime and nutrient load. This condition is characterized by very little water exchange and a low nutrient level with low productivity of plankton communities. There is the development of submerged macrovegetation in littoral zone and a specific seasonal change in chemistry and biological parameters. However, the aquatic ecosystem is still far from stabilized and the biological communities of the littoral zone (littoral) and open water (pelagial), including the fish community, still show significant interannual dynamics.
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Hydrobiological monitoring of Lake Medard in 2020.
Peterka, Jiří ; Hejzlar, Josef ; Nedoma, Jiří ; Znachor, Petr ; Seďa, Jaromír
The aim of this report is to summarize the results achieved in 2020 and make recommendations for further monitoring. The year 2020 was the third year after the full filling of the lake. The lake ecosystem has reached a final state in terms of hydrological regime and nutrient load, which is characterized by very low water turnover, low trophic state with low productivity of planktonic communities, development of submerged macrovegetation in littoral areas and specific seasonal changes in chemistry and biological parameters. However, the aquatic ecosystem is far from being stabilized and the biological communities of the littoral and the open water areas, including the fish community, are still changing considerably from year to year.
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Environmental gradients in canyon-shaped reservoirs
Stodola, Jakub ; Petrusek, Adam (advisor) ; Seďa, Jaromír (referee)
The occurrence of environmental gradients in canyon-shaped reservoirs is influenced mainly by the size of reservoir and water retention time. The reservoir must be large and deep enough for environmental gradients to occur there. In such reservoirs vertical and horizontal gradients can be found. Presence of vertical gradients in lakes is relatively common, whereas horizontal gradients abound in deep canyon reservoirs. An example is the gradient of nutrients, the quantity of which decreases in the direction from the inflow towards the dam. Vertical abiotic gradients are the same for reservoirs and lakes. These are mainly gradients of light, heat, dissolved and oxygen. Some abiotic horizontal gradients may be present in both to reservoirs and lakes. The abiotic gradients also often affect the biotic ones. For example the gradient of nutrients affects the gradient of all organisms in the reservoir. Each species living in the reservoir prefers different type of environmental conditions, which may be given by a combination of these gradients. The areas preferred by particular cladoceran species can overlap quite extensively. In the Daphnia longispina species complex, co-occurrence of parental species may result in interspecific hybridization, and possibly formation of hybrid zones. The hybrids can often...
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Hydrobiological monitoring of Medard lake in 2019
Hejzlar, Josef ; Nedoma, Jiří ; Znachor, Petr ; Seďa, Jaromír ; Peterka, Jiří
Presented report summarizes the results of hydrobiological monitoring of Medard Lake in 2019 and recommends further monitoring actions. The year 2019 was the second year after the lake was filled, when no more water from the Ohře River was filled and only small tributaries from the small river basin flowed into the lake. Thus, the ecosystem of the lake has reached a final state in terms of hydrological regime and nutrient load, characterized by very low water exchange, low trophic levels with low productivity of planktonic communities, development of submerged macrovegetation in coastal zones and specific seasonal changes in chemistry and biological parameters.
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Hydrobiological monitoring of Medard Lake in 2018
Hejzlar, Josef ; Nedoma, Jiří ; Znachor, Petr ; Seďa, Jaromír ; Peterka, Jiří
Presented report summarizes the results of hydrobiological monitoring of Medard Lake in 2018 and recommends further monitoring actions. The year 2018 was the first year after the lake was filled, when no more water from the Ohře River was filled and only small tributaries from the small river basin flowed into the lake. Thus, the ecosystem of the lake has reached a final state in terms of hydrological regime and nutrient load, characterized by very low water exchange, low trophic levels with low productivity of planktonic communities, development of submerged macrovegetation in coastal zones and specific seasonal changes in chemistry and biological parameters.
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Hydrobiological monitoring of Medard Lake in 2017
Hejzlar, Josef ; Nedoma, Jiří ; Znachor, Petr ; Seďa, Jaromír ; Peterka, Jiří
The report summarizes the results of hydrobiological monitoring of Medard Lake 2017 and contains recommendations for further research activities. At the beginning of 2017, the lake was almost full, and at the end of March the last 30 cm water column was filled from the Ohře river. The ecosystem of the lake has reached its final nutrient load, which will be characterized by low levels of carrying capacity with low productivity planktonic and fish communities and specific seasonal changes in chemistry and biological parameters.
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