Fig. 5.

Pseudocobalamin and cobalamin producers at station 3. Shown are particulate cobalamin (closed blue circles), pseudocobalamin (orange open circles), prokaryote cell abundance (black diamonds), and in situ fluorescence (gray). Bar graphs show prokaryote population with the following predicted cobalamin strategies: unlikely producers (gray), bacteria with unknown cobalamin biosynthesis capacity (gray/blue striped), bacteria that are likely to produce cobalamin (blue), Thaumarchaeota (likely to produce cobalamin, white), and Cyanobacteria (likely to produce pseudocobalamin, orange) at the corresponding depths. Cobalamin and pseudocobalamin concentrations are as in Fig. 2.