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Litter decomposition and its role in biogeochemical cycles
Vicena, Jakub ; Frouz, Jan (advisor) ; Picek, Tomáš (referee) ; Krištůfek, Václav (referee)
Decomposition of litter is a key process in the soil nutrient cycle. It is a very complex process that is influenced by a number of factors. This dissertation studies these key factors influencing the rate of organic matter mineralization using modern analytical methods. The results of the dissertation are presented in four publications in international journals with IF and one manuscript ready for publication. The first publication shows a strong positive correlation between microbial diversity and organic matter decomposition per gram of carbon. In contrast, microbial respiration per gram soil was negatively correlated with bacterial diversity and positively correlated with fungal biomass. Thus, the relationship between microbial diversity and decomposition rate is context dependent. The second study (in manuscript form) shows that microbial respiration correlates with C/N of fallout only at the beginning of the experiment, but not at the end. However, respiration during litter decomposition at the beginning and end of the experiment is strongly negatively correlated with the C/N ratio of green leaves. This suggests that the stoichiometric C/N ratio may influence decomposition indirectly through correlation with other unknown parameters such as leaf morphology. The third study examined the...
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Effect of available P and phenolics on mineral N release in acidified spruce forest: connection with lignin-degrading enzymes and bacterial and fungal communities
VANĚK, Daniel
Annotation We conducted over four months a shortterm laboratory incubation experiment to find the best prediction parameters (i.e. initial chemical characteristics) to explain differences in microbial respiration rates and mineral N (DIN) release in different litter in an acidified spruce forest. In addition, we wanted to find the link between the activity of key extracellular ligninolytic enzymes, phenoloxidases (PhOx) and peroxidases (PerOx), microbial respiration and composition of fungal and bacterial communities. Samples of spruce needles (Picea abies) and litter of four dominant understorey vegetation; lady fern (Athyrium alpestre), blueberry (Vaccinium myrtillus), reedgrass (Calamagrostis villosa) and hair grass (Avenella flexuosa), were collected in 2005, 2006 and 2007 from six sites located in watersheds of two glacial lakes (Plešné Lake and Čertovo Lake) in the Bohemian Forest, Czech Republic. Litter samples were incubated at 0 and 10 °C in laboratory controlled conditions for 90 days. Activities of PhOx and PerOx, and C mineralization rate were measured regularly each 14 days. Litter quality characteristics and endophytic microbial community structure, based on 16SrDNA-DGGE fingerprint of bacteria and ITS-DGGE of fungi, were determined at the beginning and end of litter incubation. Our results showed a close correlation of phenolics/POX with DIN release (r ? 0.74, p ? 0.001). Using multivariate analyses, POX seems to play an important role in the change of litter fungal and bacterial community composition. At 0 °C the fungal and bacterial communities of reedgrass and blueberry litter changed in relation to POX and PerOx activity, while at 10 °C the fungal communities after the incubation were additionally affected by the phenolics/NTOT and phenolics/PTOT ratios.
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Změny ve společenstvech půdní mikroflóry a mesofauny během rozkladu listového opadu ve dvou vegetačních zónách - litter bag experiment
Jirout, Jiří ; Petrásek, Jiří ; Čápová, Lenka ; Farská, Jitka ; Jínová, Kristýna ; Rusek, Josef ; Krištůfek, Václav ; Elhottová, Dana ; Starý, Josef ; Nováková, Alena
The hypothesis, whether autochthonous species of soil biota are able to decompose litter from lower vegetation zones in higher zones, was tested by field trial. Litterbags with litter of beech (.i.Fagus sylvatica./i. L.) and/or oak (.i.Quercus robur./i. L.) were exposed in beech and spruce forest on the mountain Kleť (Protected Landscape Area Blanský les). Litterbags layout simulated vegetation zones shift to the higher altitude induced by global warming. There were used litterbags with three different mesh size (42 µm, 0,5 mm, 2 mm) for exclusion of certain parts of edaphon. Several changes of soil bacteria and micromycetes, oribatid mites, springtails and gamasid mites were studied during two years of exposition. There were exposed 480 litterbags at the start of the experiment (November 2002). After 2, 4, 6, 12, 24 months of exposition parts of all litterbags were recovered. Immediately after the sampling litter pH(KCl), moisture and mass loss were measured.
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