“…In meta genomic surveys from oligotrophic stratified environments, including the northwest Pacific Ocean and the Sargasso, Mediterranean, and Red Seas, Pro chlorococcus, Verrucomicrobiales, Flexibacteraceae, Euryarchaeota, and Gamma-, Delta-, and Alphaproteobaceria dominated surface-water microbial pop ulations (DeLong et al 2006, Ferreira et al 2014, Thompson et al 2017. The dominant metabolic path ways in surface waters (based on sequence similarity searches of metagenome sequences against protein data bases) included chlorophyll and caro tenoid biosynthesis, carbon fixation, light-induced DN A repair, oxidative stress responses, nitrogen and phosphate metabolism, and vitamin B6 metabolism (DeLong et al 2006, Ferreira et al 2014, Thompson et al 2017. At aphotic depths, representatives from Deferribacteres, Planctomycetaceae, Acidobacteriales, Gemmatamonadaceae, Nitrospina, Alteromonadaeceae, andThaumarchaeota prevailed (DeLong et al 2006, Ferreira et al 2014), while characteristic metabolic functions included protein folding and export, glyoxylate and dicarboxylate metabolism, thiamine metabolism, methane oxidation, selenocysteine metabolism and terpenoid biosynthesis, and sulfate assimilation and metabolism (DeLong et al 2006, Ferreira et al 2014.…”