Significant spatiotemporal pattern of nitrous oxide emission and its influencing factors from a shallow eutropic lake in Inner Mongolia, China.

• Remarkable spatiotemporal pattern of N2O concentrations and fluxes were observed. • Factors controlling N2O emission vary across lake zones and seasons. • Seasonally frozen eutrophic shallow lakes in cold regions can be a source of N2O. • Northern part of the lake near the drained inlet is a "hotspots" for N2O emission. Eutrophic shallow lakes are generally considered as a contributor to the emission of nitrous oxide (N 2 O), while regional and global estimates have remained imprecise. This due to a lack of data and insufficient understanding of the multiple contributing factors. This study characterized the spatiotemporal variability in N 2 O concentrations and N 2 O diffusive fluxes and the contributing factors in Lake Wuliangsuhai, a typical shallow eutrophic and seasonally frozen lake in Inner Mongolia with cold and arid climate. Dissolved N 2 O concentrations of the lake exhibited a range of 4.5 to 101.2 nmol/L, displaying significant spatiotemporal variations. The lowest and highest concentrations were measured in summer and winter, respectively. The spatial distribution of N 2 O flux was consistent with that of N 2 O concentrations. Additionally, the hotspots of N 2 O emissions were detected within close to the main inflow of lake. The wide spatial and temporal variation in N 2 O emissions indicate the complexity and its relative importance of factors influencing emissions. N 2 O emissions in different lake zones and seasons were regulated by diverse factors. Factors influencing the spatial and temporal distribution of N 2 O concentrations and fluxes were identified as WT, WD, DO, Chl-a, SD and COD. Interestingly, the same factor demonstrated opposing effects on N 2 O emission in various seasons or zones. This research improves our understanding of N 2 O emissions in shallow eutrophic lakes in cold and arid areas. [Display omitted] [ABSTRACT FROM AUTHOR]