Fig. 1: N2O emission mechanism in the ocean.
From: Global mapping of flux and microbial sources for oceanic N2O
a The simultaneous changes in DO and N2O in the ocean are represented by blue and red dotted lines. The source‒sink boundary of N2O, where N2O reaches its highest value and below which the water column does not contribute to N2O emissions, is identified by a comprehensive grid-by-grid (0.1°) traversal of DO up to 5000 m in the ocean. The areas with minimum O2 ≤ 10 μΜ are defined as oxygen-deficient zones (ODZs), comprising a mixed layer (ML), upper oxycline (UO), ODZ core (OC), and lower oxycline (LO). The DO generally remains stable ( > 200 μΜ) in the ML and sharply decreases to zero in the UO; while it remains the lowest (O2 ≤ 10 μΜ) in the ODZ core and then increases from the LO. The oxic-anoxic interface occurs at the source-sink boundary in ODZs. b, c The distribution of depth and DO at the source‒sink boundary of N2O, which was identified at the lowest point of oxygen. Source data are provided as a Source Data file.
