Yulia Dmitrievna Dmitrienko
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Bacterial complexes in the fens of Tomsk region: abundance, taxonomic structure, activityMoscow University Bulletin. Series 17. Soil science. 4. p.43-51read more581
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This article provides an analysis of structural and functional indicators of bacterial complexes taken for examination from the complete profile of the fens that form part of “Klukvennoye” and “Karbyshevskoye” wetland systems in the Tomsk Region. In the fens bacteria was found throughout all the profile. The number of bacteria was high and varied from 27 to 78 ´ 109 cells/g of dry peat. This data was obtained by direct method using fluorescence microscopy. The high count of the saprotrophic bacteria (reaching up to 108-109 CFU/g of dry peat) was found by the plate method. Those results allowed to identify a trend, showing that the number of saprotrophic bacteria increased down the fen profile. The results of this study give an opportunity to state for the first time that the index k ( k is a dimensionless universal characteristic of natural prokaryotic communities, k stands for microscopy/plate) in fen profiles does not increase, but decreases with depth. The following bacterial cultures were identified and isolated from the fens studied (those cultures were attributed to 10 taxa): Bacillus, Streptomyces, Arthrobacter, Microbacterium, Pseudomonas, Pedobacter, Flavobacterium, Dyadobacter, Janthinobacterium, Myxobacteriales. Bacterial cultures, representing Bacillus and Streptomyces genera, were dominant in the acrotelm. At the same time Pseudo-monas, Dyadobacter and Arthrobacter dominated in the catotelm. The functions of bacterial genera and species, identified by molecular biological methods, were described. A study of nitogen fixation, nitrogen decline and methanogenesis showed that bacteria were in a viable state and were able to remain active throughout the entire peat profile.
Keywords: fens; Sapric Histosols; bacteria; abundance; taxonomic structure; nitrogen fixation; denitrification; methanogenesis
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