Fig. 6: Environmental abundance of rhodopsin transcripts in metatranscriptomes and conceptual model of the physiological role of a diatom proton pump rhodopsin.
a, Metatranscriptome sampling stations are scaled on the basis of estimated concentration of dissolved iron. b, Normalized environmental transcript abundances of eukaryotic rhodopsins as a function of latitude. The dark blue line shows smoothed conditional means (loess smooth) of rhodopsin transcript abundances. c, Correlation of normalized environmental rhodopsin transcript abundances and estimated dissolved iron concentration from a global ocean model. d, Correlation of estimated iron stress index and environmental diatom rhodopsin transcript abundances. The P values displayed were determined using a two-tailed t-test and Benjamini–Hochberg adjusted for multiple comparisons. e, Molecular physiological model of diatom rhodopsin.
