Response of soil and rhizosphere microbial communities to long-term variability of near-ground temperature and soil moisture in a topography-shaped arctic-alpine system

• Applicants: Professorin Dr. Claudia Knief, since 3/2023; Professor Dr. Jörg Löffler
• Subject Area: Microbial Ecology and Applied Microbiology
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 491812991

Arctic-alpine systems are known to be very sensitive to the effects of progressive global warming, expressed by changes in regional temperatures and precipitation. Soil microorganisms are essential players for ecosystem functioning. To assess the impacts of ongoing climate change on the soil microbiota, it is mandatory to understand the direct influence of climate drivers in field experiments, including possible interconnected factors such as micro-topography, elevation, and vegetation. In a previous study, we demonstrated that the use of a new machine learning algorithm (Partial Least Squares Regression) enabled the analysis of extensive environmental data with microbial data, allowing a taxon-wise identification of soil moisture and near-ground temperature thresholds for the soil microbiota. This approach gave insight in the realized ecological niche of each soil microbial taxon. We here propose to use this novel approach to analyze the microbiota in soil samples collected almost annually over more than one decade to reconstruct the succession and responsiveness of the soil microbiota to weather fluctuations under consideration of ecosystem heterogeneity. Our sampling sites are located in two climatic regions and include six elevation levels, each with four micro-topographic positions. All sites are equipped with temperature and soil moisture loggers, providing a high-resolution, long-term near-ground environmental dataset. Further, plant species frequency data as well as basic physical and chemical soil properties are documented. Amplicon sequencing and qPCR specific for bacteria, archaea and fungi will be used to investigate the soil microbial community composition and abundance. The connection between microbial data and comprehensive environmental data will enable us to address four major questions: a) How sensitive is the microbiota to annual fluctuations and is it permanently affected by unusual weather events? b) Which climatic thresholds do in particular promote or impede the occurrence of microbial taxa in dependence on topographic features? c) Can dormant and active microbiota fractions be distinguished based on their realized ecological niche to provide information on the circumstances under which each fraction becomes active or inactive? d) Does the response of the rhizosphere microbiota to environmental factors differ from the bulk soil community and are topographic differences in the soil microbial communities the result of vegetation-specific promotion? Overall, this project will give broad insight into microbial life and its most influential factors in an arctic-alpine system, which is mandatory to estimate the reaction of the soil microbiome to future climate change conditions. In particular, the long-term year-to-year variability in the microbiota will show the impact of these fluctuations and thus provide insight into the robustness of the system.

• DFG Programme: Research Grants
• Ehemalige Antragstellerin: Dr. Katharina Frindte, until 3/2023