Controlling Methane Ebullition Flux in Cascade Reservoirs of the Upper Yellow River by the Ratio of mcrA to pmoA Genes

作者：Wu Yi, Xufeng Mao, Xia Liang, Wenjia Tang, Hongyan Yu, Ziping Zhang, Feng Xiao, Haichuan Ji, Yuanjie Ma · 发表于：Water · 年份：2024 · DOI：10.3390/w16182565 · 被引用次数：5 · 研究领域：Atmospheric and Environmental Gas Dynamics、Hydrocarbon exploration and reservoir analysis、Methane Hydrates and Related Phenomena

Reservoirs are an important source of methane (CH4) emissions, but the relative contribution of CH4 ebullition and diffusion fluxes to total fluxes has received little attention in the past. In this study, we systematically monitored the CH4 fluxes of nine cascade reservoirs (Dahejia, Jishixia, Huangfeng, Suzhi, Kangyang, Zhiganglaka, Lijiaxia, Nina, and Longyangxia) in the upper reaches of the Yellow River in the dry (May 2023) and wet seasons (August 2023) using the static chamber gas chromatography and headspace equilibrium methods. We also simultaneously measured environmental physicochemical properties as well as the abundance of methanogens and methanotrophs in sediments. The results showed the following: (1) All reservoirs were sources of CH4 emissions, with an average diffusion flux of 0.08 ± 0.05 mg m−2 h−1 and ebullition flux of 0.38 ± 0.41 mg m−2 h−1. Ebullition flux accounted for 78.01 ± 7.85% of total flux. (2) Spatially, both CH4 diffusion and ebullition fluxes increased from upstream to downstream. Temporally, CH4 diffusion flux in the wet season (0.09 ± 0.06 mg m−2 h−1) was slightly higher than that in the dry season (0.08 ± 0.04 mg m−2 h−1), but CH4 ebullition flux in the dry season (0.38 ± 0.48 mg m−2 h−1) was higher than that in the wet season (0.32 ± 0.2 mg m−2 h−1). (3) qPCR showed that methanogens (mcrA gene) were more abundant in the wet season (5.43 ± 3.94 × 105 copies g−1) than that in the dry season (3.74 ± 1.34 × 105 copies g−1). Methanotrophs (pmoA...