In this project within the functional microbial ecology (FUME) group at the Department of Aquatic Sciences and Assessment, we will perform demanding analyses of large metagenomic datasets generated from inland waters around the world (Swedish lakes, soda lakes and other saline lakes from around the world, pristine spring waters from the Floridian aquifer) as well as from microbial ecological microcosm experiments. Besides uncovering the unknown diversity of these poorly studied habitats, we focus on the following questions: - How does water retention time of different aquatic systems affect the functional carbon processing capabilities of the local microbiome? - How do the extreme conditions of soda lakes (high pH, high organic carbon content, extreme fluctuations due to low water levels)affect their diversity and metabolic capacities? Is there a global soda lake microbiome? - How does viral pressure impact particle associated and free-living microbial communities? - How does the extreme light climate variation characteristic to the boreal zone impact aquatic communities? To achieve the goals and answer tresearch questions the project we will partly do de novo assemblies on newly generated or collected (from databases) metagenomic libraries or will continue to process already assembled metagenomes (metagenomes from microcoms experiments). The processing of the large metagenomic data (sometimes hundreds of samples) includes computationally demanding processes such as assembly, bin sorting of reads into genomes, annotation and comparison with each other and other publicly available genomic databases. The sequences processed within the project will serve several projects supported SciLifeLab Biodiversity project, Formas, Olsson-Borgh and Wenner-Gren foundation under the leadership of Anna Székely. The project aims to be partly a continuation of the computationl project SNIC 2020/5-93.