Fig. 1.

Proteorhodopsin genes were most abundant in near surface waters but present as deep as 1000 m. a Box and whiskers plot of average copy number per genome of all proteorhodopsins found at each depth in the Station ALOHA gene catalog. The average deep chlorophyll maximum of 106 m from this sampling period is depicted as a dashed line. Statistically significant differences in abundance between samples are shown. b Bubble plot showing average copy number per genome of proteorhodopsins in all samples of the station ALOHA gene catalog. The absence of a bubble represents a lack of sample. Sampling occurred twice in November 2011. 3 November and 27 November