Recent advances in metagenomics have generated numerous insights related to the cell biology, ecology, evolution, and biogeochemistry of microbial life in the ocean. Notably, advances in single cell genomics (SCG), fluorescence activated cell sorting (FACS) capture of specific populations and metagenomic assembly are providing valuable information related to within and between lineage genomic content. Improved reference genome databases have assisted biogeographic studies of particular taxa, including in some cases different ecotypes. Several studies targeting picoplankton, associated with various particle size classes, have begun to define contrasting trends in gene family evolution between free-living compared to particle associated microbes. Also viruses and eukaryotic microbes are increasingly considered in metagenomic studies and specific associations between viruses, bacteria, archaea, and eukaryotic microbes are emerging.