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

在本项目的框架内，将研究初始生态系统中氮周转过程的演变以及相应的微生物种群。此外，氮转化过程应与其他营养循环联系起来，以确定不同发达生态系统中氮周转对其他营养物质可用性的依赖。研究不同演替阶段土壤食物网的抗逆性。此外，应检查永久冻土的功能特征，因为由于气候变化，潜在的微生物可能对未来的养分周转作出重大贡献。因此，我们计划对乔治王岛（南极海域）不同深度冰川退缩所定义的不同年代序列进行研究。为了达到上述目标，分子宏基因组学方法将用于描述微生物群落的结构和功能，以及描述选定的重要途径的调节。此外，定量实时PCR和扩增子测序将用于描述相应群体的丰度和活性。为了跟踪氮基土壤食物网，将使用15N稳定同位素探测。在这个项目中，我们希望重建生态系统发展过程中氮周转过程的演变，并确定关键的微生物种群，以提高目前对土壤中复杂养分循环的理解。

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.