show Abstracthide AbstractThe marine cyanobacteria, Prochlorococcus and Synechococcus, perform a significant fraction of ocean carbon fixation and interact with a diverse microbial community. Comparative genomics of cultivated isolates has helped address questions regarding patterns of evolution and diversity among microbes, but the fraction that can be cultivated is miniscule compared to the diversity in the wild. To further probe the functional diversity of these groups and extend the utility of reference sequence databases, we report a data set of single cell genomes for 489 Prochlorococcus, 50 Synechococcus, 190 co-occurring microorganisms, and 9 virus particles. Many of these uncultivated single cell genomes are derived from samples obtained on HOT, BATS, and GEOTRACES cruises and thus benefit from an extensive suite of chemical and physical data.