Microbial-mediated soil formation in maritime Antarctica under simulated environmental conditions

至少自1992年里约热内卢生物多样性公约以来，土壤被认为是地球可持续发展的基本媒介。向植被提供水分和养分、生物的自然栖息地以及C、N和P等生命要素的反应可能是土壤对地球上生命最重要的功能。因此，活着的土壤发挥着维持生命的功能，在南极这样的极端环境中也能维持生命。这为探索土壤微生物群落的多样性和功能及其与土壤形成过程的相互关系提供了难得的机会。在南极洲，土壤的形成不受高等植被和穴居动物的影响。此外，对微生物介导的土壤形成的研究可以得出关于南极洲与世隔绝对生物进化的影响以及关于微生物进化和土壤形成对环境变化的反应的结论。拟议的项目旨在分析在模拟的南极海洋环境条件下微生物介导的土壤形成。我们关注微生物群落结构如何控制碳固定和微团聚体的形成，作为幼年沉积物中土壤形成的主要初始过程之一。在这方面，我们将结合微生物学和土壤科学，以综合和跨学科的方法分析南极海洋的原始土壤和沉积物。首先，我们将包括分子生态学研究和土壤发生学分析，以阐明在给定的环境条件下，微生物群落对南极海洋早期土壤形成的影响。这将使我们能够分析微生物群落组成中与成壤过程有关的地点变化。接下来，我们将在实验室进行环境模拟实验(EnviSimEx)，研究环境变化(温度、湿度、有机物、冻融循环)对初始成土过程和微生物群落的影响。EnviSimEx在有微生物和没有微生物的情况下都能发挥作用，因此将有助于澄清微生物在早期土壤形成及其反馈过程中的作用。我们将以一种综合的方法将微生物方法和土壤培养方法结合起来。将应用实时聚合酶链式反应和DGGE指纹图谱以及下一代测序来分析微生物群落的结构和功能。将进行土壤物理化学分析，以确定风化强度、成壤过程和土壤性质。尖端微形态技术和纳米SIMS将有助于识别和表征微生物热点以及土壤和沉积物中的迁移和转化过程。

At least since the convention on biodiversity in Rio de Janeiro, 1992, soils are recognized as the essential medium for sustainability on the planet. Water and nutrient supply to vegetation, natural habitat for organisms and reactor of key elements of life such as C, N and P are probably the most important functions of soils for life on earth. As such, the living soil fulfils life-support functions that sustain life also in extreme environments like the Antarctic. This offers the exceptional chance to explore diversity and functioning of microbial communities in soils and their interrelations with soil forming processes. In Antarctica, soil formation proceeds without the influence of higher vegetation and burrowing animals. Furthermore, research on microbial-mediated soil formation allows conclusions about the impact of the isolation of Antarctica on biological evolution and about the response of microbial evolution and soil formation to environmental change. The proposed project seeks to analyse microbial-mediated soil formation under simulated environmental conditions in maritime Antarctica. We focus on how microbial community structures control carbon fixation and formation of micro-aggregates as one of the major initial processes of soil formation in juvenile sediments. In this respect, we will analyse initial soils and sediments from maritime Antarctica in an integrated and interdisciplinary approach combining microbiology and soil science. At first, we will comprise molecular ecological studies and pedogenic analyses to elucidate the impact of microbial communities on early soil formation under the given environmental conditions in maritime Antarctica. This will allow analysing site variations within the microbial community composition in relation to pedogenic processes. Following, we will conduct an Environmental Simulation Experiment (EnviSimEx) in the laboratory to study the impact of environmental changes (temperature, moisture, organic matter, freeze-thaw cycling) on initial pedogenic processes and microbial communities. EnviSimEx performs with and without microorganisms and will thus help to clarify the role of microorganisms on early soil formation and its feedback processes. We will combine microbiological and pedogenic methods in an integrative approach. Real time PCR and DGGE fingerprinting as well as next generation sequencing will be applied to analyse the structure and function of microbial communities. Soil physicochemical analyses will be done to determine weathering intensity, pedogenic processes and soil properties. Cutting-edge micromorphological techniques and NanoSIMS will help to identify and characterize microbial hotspots as well as translocation and transformation processes in soils and sediments.