Final Activity Report Summary - MICROBIAL DIVERSITY (Microbial diversity in aquatic ecosystems, novel microorganisms and their potential applications) The project focused on the molecular characterisation and cultivation of phylotypes of bacteria, archea and eukaryotic microorganisms from the water bodies. Microorganisms are the main players in all ecosystems, therefore it is important to understand all aspects of their ecology. Microorganisms are mostly known as the major corner stones for elemental cycling of biogeochemical cycles at global scales as well as at local scales. Despite recognition of their importance our understanding about functions of microorganisms is largely hampered because the methodological difficulties to study these organisms. The main aims of the project were: (1)to establish molecular biology methods needed for the characterization of various microorganisms at the host institute. (2)to establish the microbial ecology working group at the University of Tartu, Institute of Technology. (3)Description of microbial diversity in humic rich environments. Tasks were fulfilled, the project leader established himself at the molecular biology lab at Institute of Technology, recruited several students and continued establishing international network of collaboration with other European research institutes (e.g. Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany; the Department of Biology and Environmental Science, Kalmar University, Sweden, University of Oldenburg, Institute for Chemistry and Biology of Marine Ecosystems, Germany). Major scientific results were: - Studied environments such as peat bog pools, freshwater lakes and their upper layer of sediment etc. possess large variety of unexplored microbial diversity; considerable fraction of the microbial diversity was possible to grow in the laboratory cultures; - DNA extraction and purification protocols for environmental samples need more optimisation; - Optimisation of the DNA extraction and purification protocols for environmental samples is feasible using simple approaches such as low pressure chromatography and using chaotropic salts/silica. - Isolation of the free dissolved environmental DNA needs more efforts to result in pure isolation of this specific fraction of nucleic acids in aquatic environments. - Reasonable collection of isolates was collected in order to use them for screening secondary metabolites production.