Fig. 4: Latitudinal trends for metabolic inferences from a 16S rRNA marker gene survey.

Columns illustrate (from left to right) hypotheses and their associated secondary superclass (functional) pathways: H1 (PP), H2 (thermodynamic effects on cell biosystems machinery), H3 (coping strategies for nutrient limitation), and H4 (energy production). Graphs in the upper row illustrate measured data for PP (a) and expected values (according to the literature) for the processes relating to H2 (d20), H3 (f21 and22), and H4 (i25 and37). Graphs in the middle and lower rows show relative abundances of functional pathways predicted from 16S rRNA gene sequencing: CO2-fixation (b), energy metabolism (c), cell structure and cell wall biosynthesis (e), secondary metabolite biosynthesis (g), cofactor biosynthesis (h), carbohydrate biosynthesis (j), and lipid biosynthesis pathways (k). The oceanographic provinces are color coded: the Southern Ocean (SO; blue), the Subtropical Frontal Zone (STF; orange), the South Pacific Subtropical Gyre Province (SPSG; green) and the Pacific Equatorial Divergence Province (PED; red). Significant differences were observed between provinces unless otherwise indicated by a.