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Zhodnocení dlouhodobého vývoje chemismu vody Stropnice v úseku Údolí u Nových Hradů - Petříkov
Čeřovská, Kateřina ; Pokorný, Jan
Evaluation of long term development of chemical parameters of Stropnice river. In: Pithart,D.: Ecology of alluvial oxbows Natural floodplain (c. 800 ha) of Stropnice river near town Nové Hrady was drained and converted into agricultural land in 1980s. The natural meandring stream was straightened and deepened about 2m under the soil surface level. A high profile of flood plain soil was exposed to mineralisation and water flow from the region was accelerated. Data on water chemistry and flow rates collected before and after the drainage were evaluated. Alkalinity, conductivity, concentrations of base cations have increased after drainage which supports hypothesis that drainage accelerates matter losses from the landscape.
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Flóra zelených vláknitých řas přírodní památky Kutnar (Podle stavu vegetace v letech 1986-1990)
Gardavský, Alexander ; Skácelová, O. ; Lenský, V.
Filamentous green algae were thoroughly studied from preserved samples collected in the Kutnar pool, from which Cyanophyta had been determined earlier (Skácelová et Komárek, 1989). The progress of eutrophication of the nature reserve (mainly caused by washout from fields) and its terrestrialisation caused changes in communities of both higher plants and filamentous algae. Hydrocharis morsus-ranae and Nymphaea alba have retreated: Cladophora globulina (KÜTZ.) KÜTZ., C. rivularis (L.) HOEK /and C. fracta (O. F. MÜLL. ex VAHL) KÜTZ. and Oedogonium capillare (L.) KÜTZ. at present/ are progressing. The expansion of Oenanthe aquatica is also an important factor in the process.More interesting species are presented and illustrated in detail, particularly: Cylindrocapsa geminella WOLLE, Mougeotia scalaris HASS., Oedogonium rivulare (LeCLERC) A. BRAUN, Schizomeris leibleinii KÜTZ. and Uronema cf. africanum BORGE. Other species include: Chaetophora elegans (ROTH) C. A. AG., Cladophora fracta, C. globulina, C. rivularis, Coleochaete scutata BRÉB. and Oedogonium capillare. Uronema africanum is a new species for Czech and Slovac Republic; Oedogonium rivulare var. tongiense is a new variety for Central Europe (it is the second found of this species in Czech and Slovac Republic).Uronema and Schizomeris were studied thoroughly. Schizomeris leibleinii is morphologically highly variable. Some of their stages resemble the genus Uronema in their morphology but differ cytologically. Starch envelopes of pyrenoids are divided into a few parts in Schizomeris, in contrast to the genus Uronema. The anticipated relationship of the genus Schizomeris to other genera of filamentous green algae requires further study and cultivation.
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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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