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Gewählte Doctoral Thesis:

Katharina Keiblinger (2011): The effect of resource stoichiometry on microbial diverstiy and function in decomposing leaf litter.
Doctoral Thesis - Institut für Bodenforschung (IBF), BOKU-Universität für Bodenkultur, pp 145. UB BOKU obvsg

Data Source: ZID Abstracts

Abstract:: Microbes are major players in leaf litter decomposition and therefore understanding how they control element cycling is of paramount importance. Microbial carbon-use-efficiency (CUE) is an important parameter in determining ecosystem-level carbon (C) cycling. To investigate how variances in resource stoichiometry (C:N:P) affect microbial CUE, four microorganisms (two fungi and two bacteria) were cultured on media with different stoichiometry. While fungal CUE and resource C:nutrient ratio were positively related, bacterial CUE and resource C:nutrient ratio were negatively related. The difference in the direction of the relationship between CUE and C:nutrient for fungi vs. bacteria was consistent with differences in biomass stoichiometry and suggested that fungi have a higher C demand than bacteria. These results indicate that the links between biomass stoichiometry, resource demand and CUE may provide a mechanism for commonly observed temporal and spatial patterns in microbial community structure and function in natural habitats. To investigate microbial community structure and function as affected by resource stoichiometry, time and temperature stress, a metaproteomics approach was applied in a laboratory leaf litter decomposition experiment and a parallel analysis of environmental leaf samples. Overall, we could detect a strong impact of litter stoichiometry on microbial community structure and function. Fungi were the main producers of extracellular hydrolytic enzymes, while bacteria seemed to benefit from the presence of fungal enzymes. Temperature perturbations resulted in short- to medium-term alterations of microbial function, especially heat blocked decomposing enzymes. Finally, we addressed methodological challenges of protein extraction in a complex medium like the soil matrix by comparing four protein extraction procedures on two different soil samples (forest and potting soil).; Betreuer: Zechmeister-Boltenstern Sophie; 1. Berater: Strauss Joseph; 2. Berater: