Suspended particles potentially enhance nitrous oxide (N2O) emissions in the oxic estuarine waters of eutrophic lakes: Field and experimental evidence. (September 2019)

• Record Type: Journal Article
• Authors: Zhou, Yiwen; Xu, Xiaoguang; Han, Ruiming; Li, Lu; Feng, Yu; Yeerken, Senbati; Song, Kang; Wang, Qilin
• Is Part Of: Environmental pollution. Volume 252(2019):Part B
• Page Start: 1225
• Page End: 1234
• Publication Date: 2019-09
• Subjects: Suspended particles -- Denitrification -- N2O emissions -- Estuary -- Taihu Lake; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2019.06.076
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Estuaries are considered hot spots for the production and emissions of nitrous oxide (N2 O) and easily occur suspended particles (SPS), however, current understanding about the role of SPS in the N2 O emissions from the oxic estuarine waters of lacustrine ecosystems is still limited. In this study, field investigations were performed in the estuaries of hypereutrophic Taihu Lake, and laboratory simulations were simultaneously conducted to ascertain the characteristics of N2 O emissions with different SPS concentrations. The results showed that the N2 O emission fluxes ranged from 9.75 to 118.38 μg m −2 h −1, indicating a high spatial heterogeneity for the N2 O emissions from the estuaries of Taihu Lake. Although the dissolved oxygen (DO) concentrations were up to 7.85 mg L −1 in the estuarine waters, from where the N2 O emissions fluxes were approximately three times that of the lake regions. Multiple regression model selected the total nitrogen (TN), SPS, and DO concentrations as the crucial factors influencing the N2 O emission fluxes. Particularly for SPS, the simulation results showed that the N2 O concentrations increased gradually with the increase in the SPS concentrations of an oxic water column containing 4 mg L −1 of NO3 − -N, indicating that a high SPS concentration can accelerate the N2 O emissions. It was related to the change of denitrifying bacteria population in the SPS, as evidenced by its significantly positive correlation with N2 O emissions ( p < 0.01). Our findings will draw attentions to the role of SPS playing in the N2 O productions and emissions in eutrophic lakes, and its effect on nitrogen cycle should be considered in the future study. Graphical abstract: Suspended particles facilitate N2 O emissions in lacustrine estuary of the hyper-eutrophic lake, verified in the field and experiment.Image 1 Highlights: N2 O emission fluxes in estuaries were significantly higher than river and lake regions. N2 O emission fluxes increased with the elevated SPS concentrations in oxic water column. High N loading and SPS concentration are main control factors of N2 O emissions in estuaries.