Characteristics of soil N2O emission and N2O-producing microbial communities in paddy fields under elevated CO2 concentrations. (1st February 2023)

• Record Type: Journal Article
• Authors: Wu, Zhurong; Wang, Yuanyuan; Liu, Chao; Yin, Nan; Hu, Zhenghua; Shen, Lidong; Islam, A.R.M. Towfiqul; Wei, Zhaowei; Chen, Shutao
• Is Part Of: Environmental pollution. Volume 318(2023)
• Publication Date: 2023-02-01
• Subjects: e[CO2] -- Paddy fields -- N2O -- AOA -- AOB -- nirS -- nirK; 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.2022.120872
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: The effects of elevated carbon dioxide (CO2 ) concentration (e[CO2 ]) on nitrous oxide (N2 O) emissions from paddy fields and the microbial processes involved in N2 O emissions have recently received much attention. Ammonia-oxidizing microorganisms and denitrifying bacteria dominate the production of N2 O in paddy soils. To better understand the dynamics of N2 O production under e[CO2 ], a field experiment was conducted after five years of CO2 fumigation based on three treatments: CK (ambient atmospheric CO2 ), T1 (CK + increase of 40 ppm per year until 200 ppm), and T2 (CK + 200 ppm). N2 O fluxes, soil physicochemical properties, and N2 O production potential were quantified during the rice-growth period. The functional gene abundance and community composition of ammonia-oxidizing archaea (AOA) and bacteria (AOB) were analyzed using quantitative polymerase chain reaction (qPCR) and those of ammonia-denitrifying bacteria ( nirS - and nirK -type) were analyzed using Illumina MiSeq sequencing. N2 O emissions decreased by 173% and 41% under the two e[CO2 ] treatments during grain filling and milk ripening, respectively ( P < 0.05). N2 O emissions increased by 279% and 172% in the T2 treatment compared with T1 during the tillering and milk-ripening stages, respectively ( P < 0.05). Furthermore, the N2 O production potential was significantly higher in the CK treatment than in T1 and T2 during the elongation stage. The N2 O production potential and abundance of AOA amoA genes in T1 treatment were significantly lower than those in CK treatment during the high N2 O emission phase caused by mid-season drainage ( P < 0.05). Although nirK - and nirS -type denitrifying bacteria community structure and diversity did not respond significantly ( P > 0.05) to e[CO2 ], the abundance of nirK -type denitrifying bacteria significantly affected the N2 O flux ( P < 0.05). Linear regression analysis showed that the N2 O production potential, AOA amoA gene abundance, and nirK gene abundance explained 47.2% of the variation in N2 O emissions. In addition, soil nitrogen (N) significantly affected the nirK - and nirS -type denitrifier communities. Overall, our results revealed that e[CO2 ] suppressed N2 O emissions, which was closely associated with the abundance of AOA amoA and nirK genes ( P < 0.05). Graphical abstract: Image 1 Highlights: e[CO2 ] reduced the amoA gene abundance in AOA. e[CO2 ] did not significantly alter nirS and nirK bacterial community structure. e[CO2 ] inhibited N2 O emissions from paddy fields. Long-term high CO2 concentration fumigation weakened the inhibitory effect. The abundance of AOA and denitrification influenced N2 O emission under e[CO2 ].