神农架大九湖亚高山泥炭湿地甲烷通量变化特征及其与产甲烷菌群落组成的关系

Variation Characteristics of Methane Flux and Its Relationship with the Composition of Methanogens in the Subalpine Peat Wetland of Dajiuhu,Shennongjia

2018年12月~2019年11月,采用涡度相关法和高通量测序技术,以湖北省神农架大九湖亚高山泥炭湿地为研究对象,对甲烷(CH4)通量以及产甲烷菌群落组成进行相关研究。结果及分析表明:大九湖泥炭湿地研究期间表现为CH4的源,CH4总排放量为9333.26 mg·m^(-2),CH4日平均排放通量为18.50 nmol·m^(-2)·s^(-1),冬、春、夏、秋四季的CH4平均排放通量分别为6.46、4.62、36.81、25.92 nmol·m^(-2)·s^(-1),存在明显的季节变化;研究区产甲烷菌优势菌群为Methanoregula(66.73%)和Methanocella(21.99%);对样本中产甲烷菌的Shannon指数进行双因素方差分析发现,同一季节不同深度的样本中产甲烷菌多样性存在显著差异,随着深度的增加,产甲烷菌的多样性指数呈下降趋势;同一深度不同季节的样本中产甲烷菌多样性存在显著差异;夏季产甲烷菌群落组成与CH4排放通量为强正相关关系,春季产甲烷菌群落组成与CH4排放通量为强负相关关系,Methanothermus与CH4排放通量为显著正相关关系,Methanolinea与CH4排放通量为显著负相关关系。

From December 2018 to November 2019, the eddy-covariance and high-throughput sequencing technology were used to study the methane(CH4) flux and the composition of methanogens in the subalpine peat wetland of Dajiuhu, Shennongjia, Hubei Province. The results and analysis show that the Dajiuhu peat wetland was the source of CH4 during the study period. The total CH4 emission was 9 333.26 mg·m^(-2), and the average daily CH4 emission flux was 18.50 nmol·m^(-2)·s^(-1). The average CH4 emission fluxes in winter, spring, summer, and autumn are 6.46, 4.62, 36.81, and 25.92 nmol·m^(-2)·s^(-1), respectively, and there are obvious seasonal variations.The dominant groups of methanogens in the study area are Methanoregula(66.73%) and Methanocella(21.99%).A two-factor analysis of variance was performed on the Shannon index of the methanogens in the samples. The diversity of methanogens in samples of different depths in the same season is significantly different. As the depth increases, the diversity index of methanogens shows a downward trend;the diversity of methanogens in samples of the same depth and different seasons is significantly different. The community composition of methanogens in summer is strongly positively correlated with CH4 emission flux, and the community composition of methanogens in spring is strongly negatively correlated with CH4 emission flux. There was a significant positive correlation between Methanothermus and CH4 emission flux, and a significant negative correlation between Methanolinea and CH4 emission flux.