A Comprehensive Global Aquatic N₂O Emission Database (GANED): Unravelling N₂O Emission Patterns from Different Water Bodies

Abstract. Nitrous oxide (N₂O) is not only one of the main potent greenhouse gases, but also currently the dominant ozone-depleting substance. The quantification of N₂O emissions from aquatic ecosystems, despite their global importance, is hindered by fragmented observations, inconsistent data reporting, and pronounced spatiotemporal variability. In this study, to improve accessibility, we introduce the Global Aquatic N₂O Emission Database (GANED; https://doi.org/10.6073/pasta/4a086e49a4f308679b951293b380e7b9, Nazir et al., 2026), a consolidated dataset comprising 5130 N₂O concentration records and 7386 N₂O flux measurements from 3002 sites across diverse aquatic systems, including rivers, streams, lakes, reservoirs, ponds, estuaries, coastal waters, and open seas. The dataset integrates information on aquatic N₂O emission from 426 peer-reviewed publications across 8 continents, covering the period 1980–2023. While the number of observations has increased substantially since 2000, spatial coverage remains uneven, with significant gaps across Africa and parts of high-latitude regions, including Antarctica and South America. Our dataset revealed a highly skewed distribution of N₂O concentration and flux across aquatic ecosystems, with rivers and streams exhibiting the most significant variability and functioning as emission hotspots. Lakes and estuaries showed moderate variability and emission levels, whereas seas and coastal waters were characterized by consistently lower values. Pearson correlation coefficient revealed a strong positive relationship of N₂O fluxes with ammonium (NH₄⁺; R = 0.943, p < 0.001), nitrate (NO₃^-; R = 0.691, p < 0.001), and nitrite (NO₂^-; R = 0.807, p < 0.001). Significant negative correlations were found with dissolved oxygen (DO; R = -0.205, p < 0.05), dissolved organic carbon (DOC; R = -0.977, p < 0.05), and salinity (R = -0.636, p = 0.005), while non-significant associations were observed for water temperature, total nitrogen (TN), and total phosphorus (TP). The GANED dataset facilitates improved quantification of global aquatic N₂O inventories by providing comprehensive N₂O concentrations and fluxes in water bodies, as well as metadata describing sampling location, aquatic system type, and associated environmental parameters. The magnitude and patterns of N₂O emissions from water bodies provided by the GANED database are essential in defining how these aquatic ecosystems shape our climate, refining emission estimates, identifying drivers, and guiding mitigation strategies.