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Gewählte Master / Diploma Thesis:

Flavia Gonzalez Escolano (2017): Recovery of forest soil microbial activity after multiyear drought and heavy rainfall event simulations.
Master / Diploma Thesis - Institut für Bodenforschung (IBF), BOKU-Universität für Bodenkultur, pp 62. UB BOKU obvsg FullText

Data Source: ZID Abstracts
In the context of climate change, an increase in frequency and intensity of severe droughts followed by heavy rainfall events is expected. Soil moisture is one of the major abiotic factors controlling soil microbial activity. Likewise, changes in soil water regime might cause changes in microbially driven processes and in microbial community composition are expected. The aim of this study was to determine the long term effects of repeated drying-rewetting cycles on the forest soil microbial community. For this purpose a field precipitation manipulation experiment was previously performed during 3 years in a pure beech forest (Fagus sylvatica). Two different stress levels were implemented: moderate (MT) and severe treatment (ST) plus a control (CT). During the recovery year, no manipulations were done in the study area and all plots received natural precipitation. In order to see differences between previously treated plots, soil samples were taken regularly from the 3 different treated plots and tested for abiotic parameters (NO3-, NH4+, DON, DOC, TDN and pH) and biotic parameters (microbial biomass carbon and nitrogen, enzyme activity and PLFAs) . The results showed that 3 years of drying-rewetting cycles have a legacy effect that can be seen 1 year after the cease of the manipulation. Nutrient concentrations showed differences among treatments with higher values of NO3- in MT, as well as higher DON and TDN in ST plots. Microbial biomass was higher in the plots under severe stress, while no differences among microbial groups were revealed by the PLFAs analysis. Hence, the results showed that the microbial community has suffered an alteration in its functioning caused by prolonged changes in water availability. At the same time, higher microbial biomass in plots under severe stress indicate that the soil microbial community was able to recover after the cease of the manipulation and even exceed the levels of less stressed plots.

Beurteilende(r): Zechmeister-Boltenstern Sophie

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