Nitrous oxide (N2O) emissions from the high dam reservoir in longitudinal range-gorge regions on the Lancang-Mekong River, southwest China. (1st October 2021)

• Record Type: Journal Article
• Authors: Wang, Jiawei; Wu, Wei; Zhou, Xiaode; Huang, Yaqi; Guo, Mengjing
• Is Part Of: Journal of environmental management. Volume 295(2021)
• Publication Date: 2021-10-01
• Subjects: Nitrous oxide -- Emission flux -- High-dam reservoir -- Lancang river; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2021.113027
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: Nitrous oxide (N2 O) is a greenhouse gas that should not be overlooked, and its emissions from plain reservoirs as well as small- and medium-sized reservoirs have been extensively studied; however, N2 O emission patterns from high-dam reservoirs in longitudinal range-gorge regions remain unclear. In this study, the N2 O concentration and emission flux from the high-dam Xiaowan Reservoir were investigated using static headspace gas chromatography and a boundary layer approach in the Lancang River. The factors influencing N2 O production and emissions, especially the influence of damming, were explored. Our results demonstrated that the Xiaowan Reservoir, a source of N2 O emissions, had an N2 O emission flux of 15.48 ± 2.87 μmol m 2 ·d −1 in 2019; the N2 O concentration and emission flux exhibited an increasing trend along the flow direction within the Xiaowan Reservoir but decreased downstream of the dam. During the two water seasons, water temperature, the concentration of DO, NO3 − and NH4 + are all influencing factors of the N2 O concentration in the XWR. the N2 O in the XWR during the wet season was produced by nitrification, during the dry season the production mechanism of N2 O was relatively complicated, but mainly produced by nitrification. This study advances our knowledge of N2 O emissions from high-dam reservoirs in longitudinal range-gorge regions. Graphical abstract: Image 1 Highlights: The Xiao wan Reservoir was the source of N2 O emission. The reservoir storage will increase the N2 O emission potential. Nitrification and denitrification were the main production mechanism of N2 O. The Xiao wan Reservoir was a key area for N2 O emission on the Lancang-Mekong River.