Figure 2

NCLDV genome abundance in the TOP data set. (a) Proportion of the average marker gene density for NCLDVs relative to that of prokaryotes (Bacteria and Archaea) for each of the 17 TOP metagenomes. (b) Experimentally measured prokaryotic cell densities (gray circles; 16 samples by microscopy and 13 samples by FC) were used to estimate the absolute abundances of NCLDV genomes (black squares) by rescaling the metagenome-based relative abundances. ‘S’, ‘D’ and ‘Z’ in the sample names indicate the depths from which the samples were collected: ‘S’ for surface, ‘D’ for deep chlorophyll max and ‘Z’ for oxygen minimum zone.