State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China; The Lyell Centre, School of Energy, Geoscience, Infrastructure and Society, Heriot-Watt University, Research Avenue South, Edinburgh EH14 4AP, UK.
State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
Sci Total Environ. 2022 Mar 25;814:152742. doi: 10.1016/j.scitotenv.2021.152742. Epub 2021 Dec 31.
Methanotrophs are the main consumers of methane produced in lake sediments. In shallow lakes suffering from eutrophication, methanogenesis is accelerated by the excess organic carbon input, and thus methanotrophs play a key role in regulating this methane flux as well as carbon cycling. Here, we applied nucleic acid stable isotope probing (SIP) to investigate the active methanotrophic microbial community in sediments of several shallow lakes affected by eutrophication. Our results showed that an active methanotrophic community dominated by gamma-proteobacterial methanotrophs, as well as abundant beta-proteobacterial methanol-utilizers, was involved in methane-derived carbon assimilation. Crenothrix, a filamentous methanotroph, was found to be a key methane consumer in all studied lakes. The ecological role of Crenothrix in lacustrine ecosystems is so far poorly understood, with only limited information on its existence in the water column of stratified lakes. Our results provide a novel ecological insight into this group by revealing a wide distribution of Crenothrix in lake sediments. The active methane assimilation by Crenothrix also suggested that it might represent a so far overlooked but crucial biological sink of methane in shallow lakes.
产甲烷菌是湖泊沉积物中产生的甲烷的主要消费者。在遭受富营养化的浅水湖中，由于过量的有机碳输入，甲烷生成加速，因此产甲烷菌在调节这种甲烷通量和碳循环方面发挥着关键作用。在这里，我们应用核酸稳定同位素探针（SIP）来研究受富营养化影响的几个浅水湖底泥中活跃的产甲烷微生物群落。我们的结果表明，一个以γ-变形菌产甲烷菌为主，以及丰富的β-变形菌甲醇利用菌的活跃产甲烷群落参与了甲烷衍生碳的同化。Crenothrix，一种丝状产甲烷菌，被发现是所有研究湖泊中主要的甲烷消费者。到目前为止，Crenothrix 在湖泊生态系统中的生态作用还知之甚少，只有关于其在分层湖泊水柱中存在的有限信息。我们的研究结果通过揭示 Crenothrix 在湖底泥中的广泛分布，为这一群体提供了新的生态见解。Crenothrix 对甲烷的活性同化也表明，它可能代表了浅水湖中一个迄今为止被忽视但至关重要的甲烷生物汇。
