Mechanistic understanding of nitrate reduction as the dominant production pathway of nitrous oxide in marine oxygen minimum zones.

ABSTRACT: Nitrous oxide (N₂O), a potent greenhouse gas and ozone-depleting agent, is produced intensely in oxygen minimum zones (OMZs) predominantly through nitrate reduction NO3-→N2O . However, mechanisms and controls of this pathway remain unclear. Here, we investigate the microbial ecology governing this pathway using experiments and an ecosystem model. We experimentally confirm a critical hypothesis: most NO3-→N2O denitrifiers do not utilize extracellular nitrite, an intermediate of the pathway. Model results demonstrate that the NO3-→N2O pathway is compatible with oxygen, and that its response to oxygen is heterogeneous because it is governed by niche partitioning of distinct microbial types and thus may not follow a smooth curve. Lastly, experiments demonstrate that this pathway is

SUBMITTER: Sun X 

PROVIDER: S-EPMC12504588 | biostudies-literature | 2025 Oct

REPOSITORIES: biostudies-literature