Impact of nutrients on sediment microorganism composition and cobalamin activity

The rapid growth of marine aquaculture over recent decades could potentially impact microbial life, particularly sediment-associated microorganisms. Previous research has found strong associations between high OTU richness and ammonium-oxidizing reactions, and between low OTU richness and denitrification. Furthermore, Nitrosopumilus is a cobalamin-implicated, ammonium-oxidizing archaeon that has been associated with high OTU richness. In this study, we investigated a potential association between high cobalamin abundance and OTU richness. A microcosm pollution experiment was conducted with the following media: ammonium-oxidizing, nitrate-reducing, and sulfate-reducing, each set at oxic and anoxic conditions. Over four weeks, samples were collected from each medium.