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

地形型北极-高山系统中土壤和根际微生物群落对近地温度和土壤湿度长期变化的响应

• 批准号: 491812991
• 负责人: Professorin Dr. Claudia Knief, since 3/2023
• 金额: --
• 依托单位: Geographisches Institut
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/491812991?language=en
• 关键词: Response; soil; rhizosphere; microbial; communities

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.

众所周知，北极-高山系统对全球逐渐变暖的影响非常敏感，这种影响表现为区域温度和降水的变化。土壤微生物是生态系统功能的重要参与者。为了评估持续的气候变化对土壤微生物群的影响，有必要了解气候驱动因素在野外试验中的直接影响，包括可能的相互关联的因素，如微地形、海拔和植被。在之前的一项研究中，我们证明了使用一种新的机器学习算法（偏最小二乘回归）可以用微生物数据分析广泛的环境数据，从而可以对土壤微生物群的土壤湿度和近地温度阈值进行分类识别。该方法对土壤微生物分类群实现的生态位有了更深入的认识。在此，我们建议使用这种新方法来分析十多年来几乎每年收集的土壤样品中的微生物群，以重建考虑生态系统异质性的土壤微生物群的演替和对天气波动的响应。我们的采样地点位于两个气候区，包括六个海拔高度，每个海拔高度有四个微地形位置。所有站点都配备了温度和土壤湿度记录仪，提供高分辨率、长期的近地环境数据集。此外，还记录了植物种类频率数据以及土壤的基本物理和化学性质。细菌、古细菌和真菌特异性扩增子测序和qPCR将用于研究土壤微生物群落组成和丰度。微生物数据和综合环境数据之间的联系将使我们能够解决四个主要问题：a)微生物群对年度波动有多敏感，它是否受到异常天气事件的永久影响？b)哪些气候阈值特别促进或阻碍依赖地形特征的微生物分类群的发生？c)是否可以根据已实现的生态位来区分休眠和活跃的微生物群组分，以提供每个组分在何种情况下变得活跃或不活跃的信息？d)根际微生物群对环境因子的响应是否不同于整体土壤群落，土壤微生物群落的地形差异是否是植被特异性促进的结果？总体而言，该项目将对北极-高山系统中微生物的生命及其最重要的影响因素提供广泛的见解，这对于估计土壤微生物组对未来气候变化条件的反应是强制性的。特别是，微生物群的长期年际变化将显示这些波动的影响，从而提供对系统稳健性的洞察。