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Biodiversity of standing floodplain waters and processes of its formation and preservation
Pithart, David
Water chemistry and planktic communities in the naturally eutrophic alluvial waters in the Lužnice floodplain have been studied. The floofplain waters are naturally eutrophic, with strong vertical physico-chemical gradients and oxygen depletions at the botom. Small pools and backwaters of this type have unique phytoplankton structure. Prevailing dominance of flegellates, namely Cryptophyceae, and low proportion of green chlorococcal algae and Diatoms, and almost absence of Cyanophyceae are very unusual for such eutrophic waters. Flagellate dominate thanks their ability to keep the vertical position in a permanently light limited conditions (resulted from poorly mixed water columns and intensive shading of water surface by vegetation). Floodplain geodiversity play crucial role, determining morphology and location of pools and backwaters, their exposition to flooding and inflows of underground water. Terrestial vegetation effects light exposition, leaf litter.
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Current status of nature protection and management in Lužnice floodplain
Montagová, Martina ; Pithart, David
Lužnice floodplain has been preserved in a semi-natural state in a cca 25 km long section located between the state border and the town of Suchdol n L. Meandering river is surrounded by pools and oxbows, which are flooded several timeas a year. Most of the area is now the subject of nature protection. Microorganisms (Algae), water plants, birds and other wetland biota found a refungium here. Biodiversivity is maintained by river activity and mosaic structure of the landscape, formed by e pastures and wet forests. This character of landscape is now endangered by ceasing of meadow management, hence, the large parts of floodplain are now under the succesional stages leading to the wet forest in the decrease of overall biodiversity.
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Natural flooding in Lužnice floodplain - an holistic approach
Pithart, David ; Montagová, Martina ; Hartvich, P. ; Černý, R. ; Prach, K.
Natural flooding was analysed in the Lužnice River floodplain in a holistic approach. Benefits of natural flooding can be summarised as folows: 1. Water retention is increased due to the soil absorption, evapotranspiration, filling of oxbows, pools and natural depressions and finally the space between the river terreces. Real flood event are analysed here in terms of water distribution among these processes. 2. Natural flooding reduces the loss of ionts from the watershed by flowing the river outflouw and loss of carbon loss by slowing the decomposition processes. 3. Flooding creates and maintains floodplain geobiodiversity by re-forming of floodplain subsystems and differentation of its impact on these subsystems. For these reasons, maintaining and enchenging of natural flooding seems to be a prerequisite of sustainable management of riverine landscape.
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Vertical distribution of phytolankton in flooded quarries near Blatná
Bílý, M. ; Pithart, David
About 20 allluvial pools were measured concerning the shading of their water surface, which is important for the light conditions in their water column. The effect of daytime and sunny (overcast, cloudy) weather was tested. The light intensity was measured from the boat on the virtual network at the surface and simultaneously outside the pool on an unshaded spot.
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The ecosystem of karst lakes in Spain
Pithart, David
This summary describes the ecosystem of stratified ckarstic lakes in Catalonia, Spain and explains the exportability of the knowledge to any other stratified small water body with depleted oxygen at the bottom.
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Fytoplankton aluviálních tůní
Pithart, David ; Kylbergerová, Magdalena ; Pechar, Libor ; Hrbáček, Jaroslav ; Fiala, Dan ; Bílý, Michal ; Rulík, M.
Phytoplankton of alluvial pools at Lužnice alluvium have been investigated by following methodological approaches: seasonal course of phytoplankton in two pools, extensive sampling (quarterly) of 30 pools, and phytoplankton diurnal vertical migration studies in several pools. Prevailing dominance of phytoflagellates, especially Cryptophyceae and Euglenophyceae and low contribution of coccal forms as Chlorococcales and Cyanophyte has been found as a main feature of phytoplankton community. This is caused by poor mixing of water column (large relative depth, wind protectio), where th ecoccal forms sediment out and are outcompeted by motile forms, able to determinate the position within the water column.
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Jak lze měřit relativní zastínění tůní
Bílý, Michal ; Pithart, David
Three mezotrophic flooded quarries were studied for stratification and phytoplankton vertical distribution, one also for diurnal vertical migration. Flagellates dominated at all localities, at the boundary between oxic and anoxic zone there were Cryptomonas spp. dominated assemblages occupying narrow water layers.
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Proces diverzifikace chemismu a fytoplanktonu tůní po povodni
Pithart, David
Seven floodplain pools were observed for water chemistry and phytoplankton development in the time of the end of flooding period. After the disconnection from the river stream, pools repidly developed into a heterogeneous file of water bodies in terms of oxygen concentration, chlorophyll a concentration and phytoplankton composition. Morphology, exposition to flooding, exposition to shading vegetation and different source of water inflow were found to be a key factors of this diversification.
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Fenomén tůně: úvod do morfologie, hydrologie a limnologie
Pithart, David ; Pechar, Libor ; Hrbáček, Jaroslav
Small size of pools result in large interaction with the surrounding terrestrial ecosystem. 1.Wind protection caused by banks and vegetation results in stable water column. 2. Shading of vegetation restrict the amount of light, reaching the water surface. 3. Inflows of underground water may influence the water chemistry substantially. 4. Bottom processes influence the whole water volume in larger extent compared to large lakes.
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