Tang Qiong, Li Zhe, Lu Lunhui, Xiao Yan, Wu Xinghua, Wang Dianchang
Chongqing Jiaotong University, Chongqing, China.
CAS Key Lab of Reservoir Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, China.
mSystems. 2025 Jun 25:e0053025. doi: 10.1128/msystems.00530-25.
Aerobic methanotrophy, mainly carried out by methane-oxidizing bacteria (MOB) in freshwater systems, plays a crucial role in reducing methane (CH) emissions and serves as an additional carbon source (methane-derived carbon) that supports the development of microbial food loops. However, how hydrological gradients and trophic states jointly regulate methane-derived carbon dynamics and microbial community stability in river-reservoir systems, and the interplay between these two aspects, has not been adequately explored. Here, we analyze bacterial and microeukaryotic organisms using 16S rRNA and 18S rRNA gene sequencing, respectively, in a river-reservoir complex in the upper Yangtze River basin. Our results show that species diversity and interaction strength with MOB are key to maintaining community stability in the riverine zone. In addition, the more pronounced niche differentiation also contributes to community stability in the lacustrine zone, which in turn facilitates the function of aerobic methanotrophy. In the riverine and lacustrine zones, the keystone species shift from the Alphaproteobacteria class (Alpha-MOB) to the Gammaproteobacteria class (Gamma-MOB), indicating distinct mechanisms for maintaining community stability in these zones. Moreover, methane-derived carbon in the riverine and lacustrine zones and in the mesotrophic states is crucial for supporting bacterial productivity and is associated with the highest community stability. These insights highlight the complex but important role of aerobic methanotrophy in freshwater systems.
Our study elucidates the ecological underpinnings of aerobic methanotrophy (methane-derived carbon) in freshwater systems, revealing a pivotal role of community stability in modulating aerobic methanotrophy across hydrological gradients. We identify a shift in dominant methane-oxidizing bacteria (MOB) classes from Alpha- to Gammaproteobacteria, highlighting distinct mechanisms for community stability maintenance and methane-derived carbon utilization, crucial for bacterial productivity and ecosystem health. This study enhances our understanding of methane dynamics in freshwater systems, a subject with significant implications for climate change mitigation, and provides valuable insights into the microbial food loop and carbon cycling, aligning with the focus of .
需氧甲烷氧化作用主要由淡水系统中的甲烷氧化细菌（MOB）进行，在减少甲烷（CH）排放方面发挥着关键作用，并作为一种额外的碳源（甲烷衍生碳）支持微生物食物环的发展。然而，水文梯度和营养状态如何共同调节河流水库系统中甲烷衍生碳的动态以及微生物群落稳定性，以及这两个方面之间的相互作用，尚未得到充分研究。在此，我们分别使用16S rRNA和18S rRNA基因测序分析了长江上游流域一个河流水库复合体中的细菌和微型真核生物。我们的结果表明，物种多样性以及与MOB的相互作用强度是维持河滨带群落稳定性的关键。此外，更明显的生态位分化也有助于湖泊带的群落稳定性，进而促进需氧甲烷氧化作用的功能。在河滨带和湖泊带，关键物种从α-变形菌纲（α-MOB）转变为γ-变形菌纲（γ-MOB），表明这些区域维持群落稳定性的机制不同。此外，河滨带、湖泊带以及中营养状态下的甲烷衍生碳对于支持细菌生产力至关重要，并且与最高的群落稳定性相关。这些见解凸显了需氧甲烷氧化作用在淡水系统中复杂但重要的作用。
我们的研究阐明了淡水系统中需氧甲烷氧化作用（甲烷衍生碳）的生态基础，揭示了群落稳定性在调节跨水文梯度的需氧甲烷氧化作用中的关键作用。我们确定了优势甲烷氧化细菌（MOB）类群从α-变形菌纲到γ-变形菌纲的转变，突出了维持群落稳定性和利用甲烷衍生碳的不同机制，这对于细菌生产力和生态系统健康至关重要。这项研究增进了我们对淡水系统中甲烷动态的理解，这一主题对缓解气候变化具有重大意义，并为微生物食物环和碳循环提供了有价值的见解，符合相关研究重点。
