Denitrification contributes to N2O emission in paddy soils

作者：Hua Xiang, Yiguo Hong, Jiapeng Wu, Yu Wang, Fei Ye, Jiaqi Ye, Jing Lü, Aimin Long · 发表于：Frontiers in Microbiology · 年份：2023 · DOI：10.3389/fmicb.2023.1218207 · 被引用次数：44 · 研究领域：Microbial Community Ecology and Physiology、Wastewater Treatment and Nitrogen Removal、Soil Carbon and Nitrogen Dynamics

Denitrification is vital to nitrogen removal and N 2 O release in ecosystems; in this regard, paddy soils exhibit strong denitrifying ability. However, the underlying mechanism of N 2 O emission from denitrification in paddy soils is yet to be elucidated. In this study, the potential N 2 O emission rate, enzymatic activity for N 2 O production and reduction, gene abundance, and community composition during denitrification were investigated using the 15 N isotope tracer technique combined with slurry incubation, enzymatic activity detection, quantitative polymerase chain reaction (qPCR), and metagenomic sequencing. Results of incubation experiments showed that the average potential N 2 O emission rates were 0.51 ± 0.20 μmol⋅N⋅kg –1 ⋅h –1 , which constituted 2.16 ± 0.85% of the denitrification end-products. The enzymatic activity for N 2 O production was 2.77–8.94 times than that for N 2 O reduction, indicating an imbalance between N 2 O production and reduction. The gene abundance ratio of nir to nos Z from qPCR results further supported the imbalance. Results of metagenomic analysis showed that, although Proteobacteria was the common phylum for denitrification genes, other dominant community compositions varied for different denitrification genes. Gammaproteobacteria and other phyla containing the nor B gene without nos Z genes, including Actinobacteria, Planctomycetes, Desulfobacterota, Cyanobacteria, Acidobacteria, Bacteroidetes, and Myxococcus, may contribute to N 2 O emis...