Cyanobacteria are important pioneer organisms and primary producers in microbial communities of tidal flats. Not least because of their extraordinary high tolerance and adaptability towards strongly fluctuating and extreme environmental conditions they contribute substantially to the diversity of this habitat. The aim of this DFG-founded research project is the investigation of cyanobacterial populations from microbial communities of tidal flats worldwide (subtropical to (sub-)arctic) and their patterns of diversity along geographical and ecological gradients. Based on high-throughput sequencing of 16S rRNA fragments conclusions about community composition and diversity as well as putative biogeographical patterns can be drawn.

Protists (eukaryotic microbes) are the dominant primary producers in aquatic environments and, at the same time, they are the major consumers of bacteria and thus a crucial link between phytoplankton primary production, bacterial secondary production and higher trophic levels. The ecological key role of protists is sharply contrasted by an only vague understanding of their diversity and distribution. The objective of this DFG-founded project is the investigation of diversity as well as biogeographical patterns of protists based on high-throughput sequencing of 18S rRNA + ITS fragments of plankton samples from about 250 European lakes.