The diversity and ecological significance of microbial traits potentially involved in B biosynthesis in the global ocean.

Cobalamin (B), an essential nutrient and growth cofactor for many living organisms on Earth, can be fully synthesized only by selected prokaryotes in nature. Therefore, microbial communities related to B biosynthesis could serve as an example subsystem to disentangle the underlying ecological mechanisms balancing the function and taxonomic make-up of complex functional assemblages. By anchoring microbial traits potentially involved in B biosynthesis, we depict the biogeographic patterns of B biosynthesis genes and the taxa harboring them in the global ocean, despite the limitations of detecting de novo B synthesizers via metagenomes alone.

Coping with darkness: The adaptive response of marine picocyanobacteria to repeated light energy deprivation.

The picocyanobacteria and are found throughout the ocean's euphotic zone, where the daily light:dark cycle drives their physiology. Periodic deep mixing events can, however, move cells below this region, depriving them of light for extended periods of time. Here, we demonstrate that members of these genera can adapt to tolerate repeated periods of light energy deprivation.