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

测试火成岩硬岩表面和内部微生物生物膜的分类组成与岩石表面侵蚀（风化）之间的相关性是该项目的主要主题。利用新一代测序技术（NGS）对生物膜中的光合（蓝藻、真核藻类）和异养（其他原核生物和微型真菌）组分进行了全面测定。此外，还将研究光养生物膜生物的培养物。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，将从智利沿海科迪勒拉的三个不同气候带（即SPP 1803的专用主要重点区域）收集生物膜和岩心钻探样本。根据生物膜的不同连续阶段和使用14 C加速器质谱法的年龄测定，将建立生物时标。通过岩石硬段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物化学分析，将实现对生物膜多样性变化功能的深入了解。将使用荧光原位杂交显微镜检查生物膜演替阶段内生物群的空间分布和相对丰度。将在取样地点暴露人造硬岩石表面，以便对生物膜和侵蚀（风化）的定植进行平行研究。为了进一步发展岩石侵蚀碎屑的生物时间尺度，将对岩石附近的岩石颗粒进行检查，即带有生物膜的岩石颗粒已经通过变质而破碎。它们的生物膜微生物多样性可能形成其定殖的种子，甚至在更晚的阶段，形成土壤的定殖。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，将使用宇宙成因核素分析。使用CNA，将测试1）生物膜的物种（OTU）组成与岩石侵蚀之间是否存在关系，如果存在，则在何种程度上存在关系，以及2）正在发生表面的逐渐侵蚀（生物退化）。在干旱的北方研究区域（阿塔卡马沙漠），预计也会出现无法检测到生物膜的表面。然后，比较有和没有生物膜的样品中宇宙成因核素的浓度，将评估生物膜是否对表面劣化产生长期控制。

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.