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)

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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.