Fig. 4

a Phylogenetic tree of rhodopsin genes detected in the different depth metagenomes. Sequences obtained in this work are represented according to depth and color absorption (green or blue). b Number of assembled rhodopsin genes at different depths. Reads annotated as rhodopsin normalized by the number and length of recA+radA genes (estimated rhodopsin genes per genome) are indicated by red squares. c Recruitment of all rhodopsins including those obtained in this work together with the publicly available in the MicRhoDE database. Left panel, rhodopsins classified according to their taxa of origin. Right panel, average number of blue/green rhodopsins for each depth. Numbers within the brackets indicate the number of rhodopsins