From single processes to cycles: Evolution of nitrogen turnover in terrestrial ecosystems of the maritime Antarctic

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In the frame of this project the evolution of nitrogen turnover processes in initial ecosystems as well as the corresponding microbial populations shall be investigated. Furthermore, nitrogen transformation processes shall be linked to other nutrient cycles to identify the dependency of nitrogen turnover in differently developed ecosystems on the availability of other nutrients. Moreover, stress tolerance of soil food webs at different succession stages shall be investigated. Additionally, the functional traits of permafrost shall be examined, as due to climate change the underlying microorganisms may probably contribute significantly to nutrient turnover in the future. Therefore, it is planned to investigate different chronosequences defined by glacial retreat at King George Island (maritime Antarctica) in different depths. To reach the described goals, molecular metagenomic methods will be used to characterize the structure and function of microbial communities as well as to describe the regulation of selected important pathways. In addition, quantitative real time PCR and amplicon sequencing will be used to describe the abundance and activity of the corresponding populations. To follow nitrogen-based soil food webs, 15N stable isotope probing will be used. With this project we want to reconstruct the evolution of nitrogen turnover processes during ecosystem development as well as to identify the key microbial populations to improve the current understanding of complex nutrient cycles in soils.