Targeted amplicon sequencing of the 16S V4 and 18S V4 rRNA genes from microplankton DNA collected via filtration of seawater. Samples obtained from 24 sampling stations across the Western North Atlantic as part of work conducted for NSF Award #1350710: "Method Development for High-Resolution Underway N2 Fixation Measurements", with the goal of characterizing the marine microplankton community and relating community structure to measured productivity and nitrogen fixation rates.