Functional redundancy of seasonal vitamin B biosynthesis pathways in coastal marine microbial communities.

Vitamin B (cobalamin) is a major cofactor required by most marine microbes, but only produced by a few prokaryotes in the ocean, which is globally B -depleted. Despite the ecological importance of B , the seasonality of B metabolisms and the organisms involved in its synthesis in the ocean remain poorly known. Here we use metagenomics to assess the monthly dynamics of B -related pathways and the functional diversity of associated microbial communities in the coastal NW Mediterranean Sea over 7 years.