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Ecohydrology presumes that physical external variables have a major influence on the biological components of an ecosystem and vice versa. The relationships between physical factors and biological components may be useful tools in environmental management. It requires, however, that these relationships are known quantitatively. It is only possible through the development of a proper model for the ecosystem, because of the high complexity of the ecological network involved. A "proper model" is a model that can account for changes in species composition and adaptation, when the prevailing conditions are changed, i.e., a structurally dynamic model. The paper presents a model, that shows how a change from a constant out-flow rate from a reservoir to an out-flow rate that is purposely higher at the time of spring and summer bloom and at the time of spawning for planktivorous fish, is able to reduce the eutrophication level. The model presented in this paper considers only the phosphorus cycle, because phosphorus is presumed to be the limiting nutrient for phytoplankton growth. Two more ecohydrological examples that could be used quantitatively by use of a proper model are mentioned. The conclusion is, that ecohydrology offers possible and appropriate environmental management solutions but that a proper model for the considered cases is required to utilise ecohydrological possibilities quantitatively.
The studies were carried out in the littoral zone of six lakes differing in trophic and biotic diversity. These were: L. Piaseczno - the mesotrophic lake with the well developed psammolittoral, L. Uściwierz - the slightly eutrophic lake with the psammolittoral and phytolittoral, the hypertrophic lake L. Głȩbokie Uścimowskie with the psammolittoral, L. Bikcze and L. Łukie - both the eutrophic lakes with phytolittoral, and the dystrophic L. Moszne - with peatbog phytolittoral. During the spring and the summer-autumn seasons in 1996-1997 the physical and chemical composition (temperature, electrolytic conductivity, O₂, pH, total water hardness, nitrogen compounds and phosphorus compounds) of water were investigated in the littoral zone in these lakes.
Studies on the influence of physical and chemical factors on the activity of chitinases produced by planktonic bacteria isolated from Jeziorak Lake were carried out. The results evidenced maximum activity of bacterial strains at pH 6.0 and at 10°C and 30°C. Among the strains studied, higher activity was recorded along with an increase in colloidal chitin concentration. The highest activity was recorded at 2% concentration of chitin. The majority of strains hydrolyzed chitin most intensely after 192 h of incubation, whereas no strain revealed chitinases activity after 48 h.
Ustalono stosunki molowe pepsyny i protaminy w nierozpuszczalnych kompleksach oraz wpływ czynników fizycznych i chemicznych na trwałość tych kompleksów.
The effect of 3 levels soil compaction (low - 1.30, moderate - 1.47 and severe - 1.58 g·cm⁻³) on triticale and maize seedling shoots and root dry matter, leaf number, number and length of particular components of the root system, leaf injury (LI), leaf water potential (Ψ), chlorophyll content (Chl) and maximum quantum yield of PS II (Fv/Fm) were examined. For both examined species high level of soil compaction strongly affected the length of seminal and seminal adventitious roots and the number and length of nodal roots. Comparing to maize, a slightly weaker impact of soil impedance on the number and length of developed root system was observed in triticale. After 3 or 6 weeks of growth in the conditions of moderate and severe soil compaction a decrease in leaf number, dry matter of shoot and roots, and increase in leaf injury index and shoot to root (S/R) dry matter ratio were observed. Changes in root architecture under a high soil impedance were accompanied by changes in the leaf injury index (LI), leaf water potential (Ψ), chlorophyll content (Chl) and maximum quantum yield of PS II (Fv/Fm). On moderate or severe soil compaction level changes of the values of LI, Ψ, Chl and Fv/Fm were higher and statistical significant as comparing to a low soil compaction treatment. Similarly as in the case of root growth characteristic changes in physiological traits measured in leaves showed weaker impacts of high soil compaction for maize than triticale.
Ustalono stosunki molowe pepsyny i białek zasadowych (histon, lizozym, cytochrom c, rybonukleaza) w nierozpuszczalnych kompleksach oraz wpływ czynników fizycznych i chemicznych na trwałość tych kompleksów.
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