Correlation between composition of microbial biofilms and weathering of exposed rock surfaces (biodeterioration) along a climatic and temporal gradient in Chile

测试存在于火成岩坚硬岩石表面和内部的微生物生物膜的分类组成与岩石表面侵蚀（风化）之间的相关性是本项目的主要主题。利用新一代测序技术（New Generation Sequencing， NGS）全面测定生物膜中光养（蓝藻、真核藻类）和异养（其他原核生物和微真菌）组分的多样性。此外，还将研究光养生物膜生物的培养。生物膜组成的变化将沿着湿度和温度的气候梯度进行分析。因此，生物膜和岩芯样品将从智利沿海科迪勒拉的三个不同气候带收集，即spp1803的专用主要重点区域。利用14C加速器质谱法测定生物膜的不同连续阶段和年龄，建立生物时间标度。通过岩石坚硬部分剖面的高分辨率成像以及生物膜-岩石界面微生物代谢活动的生化分析，可以进一步了解生物膜多样性变化的功能。空间分布和相对丰度的生物群体内的生物膜演替阶段将检查使用荧光原位杂交显微拷贝。人工坚硬的岩石表面将暴露在采样点，以平行研究生物膜和侵蚀（风化）的定植。为了进一步发展岩石附近的岩石侵蚀碎屑的生物时间尺度，即带有生物膜的岩石颗粒，已经通过变质而碎裂。它们的生物膜微生物多样性可能形成它们定植的种子，甚至在更晚的阶段，定植土壤。这将提供一个从岩石退化到土壤微生物群落发展的界面。为了研究生物膜对侵蚀的影响，并建立地质时间尺度的宇宙核素分析（CNA）。CNA将测试1)生物膜的种类（OTU）组成与岩石侵蚀之间是否存在关系，如果存在，则在多大程度上存在关系；2)表面正在发生逐渐的侵蚀（生物退化）。在干旱的北部研究区（阿塔卡马沙漠），表面也没有可检测到的生物膜。比较有生物膜和没有生物膜的样品中宇宙核素的浓度将评估生物膜是否对表面退化起长期控制作用。

To test for a correlation between the taxonomic composition of microbial biofilms present on surfaces and inside of igneous hard rocks and the erosion (weathering) of the rock surfaces is the main subject of this project. The diversities of phototrophic (cyanobacteria, eukaryotic algae) as well as heterotrophic (other prokaryotes and microfungi) components of the biofilms will be determined comprehensively by using New Generation Sequencing (NGS). In addition, also cultures of phototrophic biofilm organisms will be studied. Changes in the biofilm composition will be analyzed along a climatic gradient of moisture and temperature. Therefore, biofilm and core drill samples will be collected from three different climatic zones in the Coastal Cordillera in Chile, i.e. the dedicated primary focus areas of the SPP 1803. From different successional stages of the biofilms and age determinations using 14C accelerator mass spectrometry a biological timescale will be established. Increased insights into the functionality of diversity changes of the biofilms will be achieved with high resolution imaging of rock hard part sections as well as biochemical analyses to trace signatures of microbial metabolic activity at the biofilm-rock interface. The spatial distribution and relative abundances of the organism groups within the biofilm successional stages will be examined using fluorescence in situ hybridization microcopy. Artificial hard rock surfaces will be exposed at the sampling sites for a parallel study of colonization by biofilms and erosion (weathering). To further develop the biological time scale of rock erosion detritus in the close vicinity of the rocks, i.e. rock particles with biofilms that already chipped of the rocks through deterioration, will be examined. Their biofilm microbial diversity may form the seeds for their colonization and, at an even later stage, the colonization of soil. This will provide an interface from rock deterioration to the development of microbial communities of the soil. To study the effects of biofilms on erosion and to establish a geological time scale Cosmogenic Nuclide Analyses (CNA) will be used. With CNA it will be tested 1) whether and if so to which extend there is a relationship between species (OTU) composition of the biofilms and rock erosion and 2) a gradual erosion of the surfaces (biodeterioration) is taking place. In the arid northern study area (Atacama Desert) also surfaces without detectable biofilm are expected. A comparison of concentrations of cosmogenic nuclides from samples with and without a biofilm will then assess whether biofilms exert a long-term control of surface deterioration.