Microbial nitrogen guilds in the oceans: from the bathypelagic to the ocean surface

Microbial nitrogen guilds play crucial roles in the oceanic nitrogen cycle, but their composition and importance across specific depths and conditions remain unclear. In this study, we examine the guilds participating in nitrogen transformations within the low and mid-latitude ocean ecosystems, from the surface down to 4000 m, using data obtained from 75 samples belonging to 11 stations in the Malaspina (MP) dataset. In particular, we used a quantitative approach to investigate the stability of nitrogen acquisition and nitrogen-redox guilds separately. Our results showed that nitrogen acquisition guilds are more stable and redundant than nitrogen-redox guilds across depths and conditions related to specific water columns. However, differential conditions such as nitrogen depletion and oxygen availability affected the two groups of guilds in different ways. These findings have significant implications for the understanding of global nutrient fluxes and the biosphere’s functional diversification. ### Competing Interest Statement The authors have declared no competing interest.