Quantitative metagenomics for marine prokaryotes and photosynthetic eukaryotes (radA and recA gene databases)

Most sequencing approaches yield only relative microbial abundances, limiting ecological and biogeochemical insights. Here, we present a spike-in quantitative metagenomics to estimate the absolute abundances of prokaryotes and eukaryotic phytoplankton in unfractionated seawater along the Atlantic Meridional Transect. By combining genomic internal standards with single-copy marker genes, this approach enables domain-spanning quantification with genus- to family-level resolution. The DIAMOND blastx databases for the single-copy genes radA and recA genes were uploaded.