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EN
Decomposition process in the soil of desert, steppe and mountain landscapes was studied in the region of Caucasus (Daghestan). The study sites differed mainly in average temperature and humidity being generally extremely dry with soil poor in organic matter. Two methods - bags with grass and cellulose filter paper discs were used. No dependence was found between the rate of decomposition of introduced organic matter and organic nitrogen content, and C:N ratio in soil, but strong dependence was found with temperature and humidity conditions. The measured rate of organic matter decomposition in soil of desert, steppe, and mountain sites indicated that the level of decomposition activity of these soils is high. In summer it is lowest in steppe (1.97 mg [x] g^-1 [x] 24 h^-1), whereas the highest in mountains (5.68 mg [x] g^-1 [x] 24 h^-1). The annual average rate of decomposition of cellulose discs and hay in mountain site was almost two times higher than in steppe site and nearly three times higher than in desert site. Mainly climatic conditions i.e. long-lasting drought (almost all the year) in desert as well as in steppe (January to August) are responsible for this difference.
EN
Neustonic (film layer -90 [mi]m, surface layer - 240 [mi]m) and planktonic bacteria (subsurface layer - 10-15 cm) participating in the processes of decomposition of organic macromolecular compounds, and their potential capability to synthesise extracellular enzymes were studied in a shallow estuarine lake (Lake Gardno - Baltic coast). The studied bacteria were capable of decomposing a wide spectrum of organic macromolecular compounds. Most bacteria inhabiting surface and subsurface water layers hydrolysed lipids, proteins and DNA. The microflora hydrolysing cellulose was represented by the least abundant group of organisms. Of the studied enzymes, alkaline and acid phosphatases, leucine arylaminase, esterase, and esterase lipase were synthesised most actively while [Beta]-glucouronidase ([Beta]Gl) and a-fucosidase ([alfa]Fu) were synthesized least actively. It can be clearly seen that enzymatic activity was stratified, and there were differences between studied water layers. Bacterial strains isolated from surface and subsurface layers were more active in synthesizing extracellular enzymes than bacteria inhabiting the film layer. Bacteria isolated from various parts of Lake Gardno synthesized the tested hydrolytic enzymes with a similar intensity.
EN
Neustonic (film layer ~ 90 µm, surface layer ~ 240 µm) and planktonic bacteria (subsurface layer ~ 10–15 cm) participating in the processes of decomposition of organic macromolecular compounds, and their potential capability to synthesise extracellular enzymes were studied in a shallow estuarine lake (Lake Gardno – Baltic coast). The studied bacteria were capable of decomposing a wide spectrum of organic macromolecular compounds. Most bacteria inhabiting surface and subsurface water layers hydrolysed lipids, proteins and DNA. The microflora hydrolysing cellulose was represented by the least abundant group of organisms. Of the studied enzymes, alkaline and acid phosphatases, leucine arylaminase, esterase, and esterase lipase were synthesised most actively while β-glucouronidase (βGl) and α-fucosidase (αFu) were synthesized least actively. It can be clearly seen that enzymatic activity was stratified, and there were differences between studied water layers. Bacterial strains isolated from surface and subsurface layers were more active in synthesizing extracellular enzymes than bacteria inhabiting the film layer. Bacteria isolated from various parts of Lake Gardno synthesized the tested hydrolytic enzymes with a similar intensity.
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2008
|
tom 17
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nr 3
427-432
EN
Being a component of atmospheric air, carbon dioxide is widely distributed in nature and constantly exchanged between the atmosphere and ecosystems. It also serves as an indicator of the rate of processes taking place in the soil environment and reflects the rate of organic matter decomposition during industrial waste management and degraded land reclamation. Human activity may increase CO₂ emission to the atmosphere, thus contributing to its higher concentration in atmospheric air. CO₂ content of soil air is modified by a variety of factors, including temperature, humidity, porosity, root respiration, etc. CO₂ emitted to the atmosphere is the product of numerous chemical processes, primarily organic matter decomposition under aerobic and anaerobic conditions, and urea decomposition. This paper presents experimental results concerning CO₂ emission from light soil deposit in the form of overburden, before and after fertilization with sewage sludge. CO₂ emission was determined in a controlled environment chamber at a temperature of 10, 20 and 30°C and a constant water capacity of 60%. It was found that both higher temperatures and the addition of sludge increased CO₂ emission to the atmosphere. The observed relationships were confirmed by an analysis of variance, and correlations between the tested variables and CO₂ emission were determined.
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