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Microbes are the main drivers of biogeochemical cycles on Earth and even though freshwaters cover only a small area of terrestrial surfaces their contribution to global cycles is important. Global cycles are measured by exchanges between systems e.g. water to atmosphere or lithosphere and are mediated by microbial communities. Cyanobacteria and other photosynthetic microbes can be highly abundant going through cyclic blooms. These blooms are attributed to their ability to harness sunlight and CO2 to outgrow competitors by using their complex and expensive to produce photosystems. In contrast there are microbial lineages termed ‘streamlined’, that are just as abundant as cyanobacteria at times, but who have much smaller cells, small genomes, and grow and replicate slowly. It is not immediately apparent how microbes with such different lifestyles can have similar ‘success’. By investigating individual streamlined lineages and their interactions we see that they appear to have co-evolved dependencies with each other and are highly successful as consortia. By comparing consortia from different lakes we see that streamlined microbes can sit either adjacent or in the middle of carbon cycling end-points and may be more directly involved than thought in mediating methane and CO2 ratios. An analysis of global inland water microbiomes finds that around one third of the core microbial lineages in inland waters are streamlined.