Daniele Bianchi

Within oxygen minimum zones, anaerobic processes transform bioavailable nitrogen (N) into the gases dinitrogen (N 2 ) and nitrous oxide (N 2 O), a potent greenhouse gas. Mesoscale eddies in these regions create heterogeneity in dissolved N tracers and O 2 concentrations, influencing nonlinear N cycle reactions that depend on them. Here, we use an eddy‐resolving model of the Eastern Tropical South Pacific to show that eddies enhance N 2 production by between 43% and 64% at the expense of reducing N 2 O production by between 94% and 104% due to both the steep increase of progressive denitrification steps at vanishing oxygen, and the more effective inhibition of N 2 O consumption relative to production. Our findings reveal the critical role of eddies in shaping the N cycle of oxygen minimum zones, which is not currently represented by coarse models used for climate studies.