Emissions of nitrous oxide from continuous permafrost region in the Daxing'an Mountains, Northeast China. (1st February 2019)

• Record Type: Journal Article
• Authors: Gao, Weifeng; Yao, Yunlong; Liang, Hong; Song, Liquan; Sheng, Houcai; Cai, Tijiu; Gao, Dawen
• Is Part Of: Atmospheric environment. Volume 198(2019)
• Page Start: 34
• Page End: 45
• Publication Date: 2019-02-01
• Subjects: N2O emission -- Permafrost -- Swamp forest -- Environmental factors -- Nitrate nitrogen -- Daxing'an mountains; Air -- Pollution -- Periodicals; Air -- Pollution -- Meteorological aspects -- Periodicals; 551.51
• DOI: 10.1016/j.atmosenv.2018.10.045
• Languages: English
• ISSNs: 1352-2310

Abstract

Abstract: Permafrost ecosystems play an important role in global climate change, and climate warming would result in permafrost thawing and changing microbial mediated N cycles. Emissions of nitrous oxide (N2 O) are an important component of N budgets in high-latitude permafrost ecosystems, especially in the context of global climate change. However, few studies have investigated the emissions of N2 O from a swamp forest in a permafrost ecosystem. In this paper, we investigated the N2 O emissions rates and cumulative budget from continuous permafrost region in the Daxing'an Mountains, northeast China, and identified the key environmental factors affecting N2 O emissions from three swamp forests in the growing season. A bootstrapping model estimated that average N2 O fluxes during the growing season were 40.76 ± 6.13, 29.56 ± 3.21 and 38.27 ± 8.46 μg m −2 h −1 from three swamp forests consisting of Larix gmelinii - Ledum palustre var. dilatatum ( LL ), Larix gmelinii - Carex appendiculata ( LC ) and Betula fruticose - Carex schmidtii ( BC ), respectively. The types of swamp forests had no statistically significant impact on N2 O emissions ( P > 0.05). The cumulative N2 O emissions were estimated to be 1.07 ± 0.09 ( LL ), 0.79 ± 0.18 ( LC ) and 1.05 ± 0.11 kg ha −1 ( BC ) in the swamp forests, indicating that the permafrost region of the Daxing'an Mountains might be a potential N2 O source during the growing season. The N2 O emissions were mainly controlled by soil temperature, water table level, pH, ammonium nitrogen, nitrate nitrogen, total organic carbon and the carbon-to-nitrogen ratio. N2 O emission showed significant negative correlation with nitrate nitrogen in the three swamp forests; thus, the low nitrate would limit the rate of N2 O emissions in the permafrost region. In addition, we found that denitrification could be the potential source of N2 O fluxes in the permafrost region of Daxing'an Mountains. Our results indicated that permafrost swamp forests were significant source for N2 O emissions, and N2 O emissions were controlled by multiple environmental factors. Graphical abstract: Highlights: N2 O emissions from permafrost in the Daxing'an Mountains, China were estimated. The types of permafrost swamp forest did not significant effect N2 O emissions. N2 O emissions from permafrost region were controlled by multiple environmental factors. Denitrification is a potential source of N2 O fluxes in permafrost region of the Daxing'an Mountains.