Changes in the genetic biodiversity of algae and cyanobacteria in terrestrial surface environments of forests and grasslands under the influences of land use and vegetation (SoilAlgae)

藻类(光自养原生生物)和蓝藻是土壤微生物群落的重要组成部分。由于它们的光自养生活方式，它们为土壤提供能量、碳和氧气输入。在土壤中，它们与其他非嗜光性原生生物和细菌相连，并与可变群落结构的功能组合相连。藻类和蓝藻对土壤生境有许多有益的影响，因为它们具有广泛的生物化学多样性，包括色素、光合作用储存产物、细胞壁和粘液、脂肪酸和其他生物活性化合物。然而，到目前为止，藻类和蓝藻的生物多样性与复杂的土壤过程的实际相关性被低估了，这可能是由于对它们的分类和遗传生物多样性的了解不足。因此，我们将通过土地利用和植被对表层土壤和相关陆地表面环境中光自养微生物群落遗传多样性的影响的综合测试，在物种和基因分辨率上评估表层土壤中藻类和蓝藻的生物多样性。这将有助于更好地了解它们在现实世界景观中生物多样性的驱动因素。因此，我们的目标是测试不同地块之间藻类/蓝藻多样性的变化(在我们的初步研究中已经观察到)是否与DFG SPP 1374的生物多样性探索提供的土地利用梯度有关。为了验证我们的工作假设，我们对所有高研究强度(VIP)的研究地块以及与所有三个生物多样性探索实验室的森林和草原联合多地点实验相关的地块进行了广泛的抽样。首先，我们的初步研究的提示需要用更广泛的采样进一步测试：枯木的光自养微生物多样性可能与表层土壤相同；它连接枯木和树皮。因此，枯木富集(狐狸实验)也可能意味着表土藻类/蓝藻多样性的丰富。我们将研究藻类/蓝藻生物多样性对森林树冠开放(FOX实验)、土壤表面干扰(例如，耕作和放牧)和施肥(FOX和LUX实验)的响应。我们将测试草原表层土壤中的藻类/蓝藻生物多样性是否超过森林表层环境。将采用基于扩增子的变位编码来评估藻类/蓝藻的多样性。23S uPA标记适用于所有真核藻类和蓝藻，并优先扩增出绿藻的ITS2。我们的初步结果表明，森林中很大一部分藻类生物多样性可能代表了仍然未知的物种或未被研究的微藻谱系。为了解决它们的系统发育关系，我们从长时间阅读的叶绿体和核标记的扩增片段中寻找详细的系统发育分析。

Algae (photoautotrophic protists) and cyanobacteria are important components of microbial communities in soil. Due to their photoautotrophic lifestyle, they provide energy, carbon, and oxygen input to soils. In the soil, they are connected to other non-phototroph protists and bacteria to functional assemblages of changeable community structure. Algae and cyanobacteria have numerous beneficial effects on soil habitats due to their broad biochemical diversity of pigments, photosynthetic storage products, cell walls and mucilage, fatty acids, and other bioactive compounds. However, the actual relevance of the biodiversity of algae and cyanobacteria for the complex soil processes has been underestimated so far, which likely is due to an insufficient understanding of their taxonomic and genetic biodiversity. Therefore, we will assess the biodiversity of algae and cyanobacteria in surface soils at species and genotypic resolution by a comprehensive testing for land-use and vegetation influences on the genetic biodiversity of photoautotroph microbial communities in topsoils and related terrestrial surface environments. It will lead to a better understanding of the drivers of their biodiversity in real-world landscapes. Therefore, our goal is to test whether the variation in the algal/cyanobacterial diversity between plots (already observed in our pilot study) can be related to the land-use gradients provided by the Biodiversity Exploratories of the DFG SPP 1374. To test our working hypotheses serves a broad sampling in all research plots of high research intensity (VIP) and those plots associated to the joint multiple-sites experiments in forests and grasslands of all three Biodiversity Exploratories. First hints from our pilot study need to be further tested with a broader sampling: photoautotroph microbial diversity of deadwood may equal that of surface soil; it connects deadwood and bark. Therefore, deadwood enrichment (FOX experiment) could means also an enrichment of topsoil algae/cyanobacteria diversity. We will study the responses of the alga/cyanobacterial biodiversity to the opening of the forest canopy (FOX experiment), soil surface disturbances (e.g., by scarifying and grazing) and fertilization (FOX and LUX experiments). We will test whether the algal/cyanobacterial biodiversity in surface soil in grasslands exceeds that of surface environments of forests. Amplicon-based metabarcoding will be employed.for assessing the algal/cyanobacterial diversity. The 23S UPA marker serves for all eukaryote algal lineages and cyanobacteria and preferentially amplified ITS2 for green algae. Our preliminary results indicate that a large portion of the algal biodiversity in forests may represent still unknown species or unstudied lineages of microalgae. To resolve their phylogenetic relationships, we seek for detailed phylogenetic analyses from long-read amplicons of chloroplast and nuclear markers.