Only a short time period is given to investigate the microbial composition of the water pond at the Zulauf AG in Schinznach. Therefor selected methods must be applied. To estimate the number of bacteria one possibility would be to use flow cytometry. It’s a modern software-based method which uses conductivity and optical measurements to sort and count cells in a fluid medium. The main advantage is the rapidness and the low costs (Lavergne, Beaugeard, Dupuy, Courties, & Agogué, 2014). Another more simpler method for counting bacteria and fungi would be to plate the sample to a petri dish and count the forming cultures (Lazarova & Manem, 1995). The plating method needs a certain incubation time and is therefore slower than flow cytometry but can be performed with simpler equipment and in the time given. Other key factors to describe the microbial community is the diversity as well as to assess specific groups of microorganisms. Most literature describes molecular methods ...