Key Laboratory of Lake and Watershed Science for Water Security, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China.
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China.
Environ Microbiol Rep. 2024 Oct;16(5):e70002. doi: 10.1111/1758-2229.70002.
The potential positive feedback between global aquatic deoxygenation and methane (CH) emission emphasizes the importance of understanding CH cycling under O-limited conditions. Increasing observations for aerobic CH-oxidizing bacteria (MOB) under anoxia have updated the prevailing paradigm that MOB are O-dependent; thus, clarification on the metabolic mechanisms of MOB under anoxia is critical and timely. Here, we mapped the global distribution of MOB under anoxic aquatic zones and summarized four underlying metabolic strategies for MOB under anoxia: (a) forming a consortium with oxygenic microorganisms; (b) self-generation/storage of O by MOB; (c) forming a consortium with non-oxygenic heterotrophic bacteria that use other electron acceptors; and (d) utilizing alternative electron acceptors other than O. Finally, we proposed directions for future research. This study calls for improved understanding of MOB under anoxia, and underscores the importance of this overlooked CH sink amidst global aquatic deoxygenation.
全球水生缺氧与甲烷 (CH) 排放之间的潜在正反馈强调了在缺氧条件下理解 CH 循环的重要性。越来越多的有氧 CH 氧化细菌 (MOB) 在缺氧条件下的观测结果更新了 MOB 依赖 O 的流行观点；因此，阐明 MOB 在缺氧条件下的代谢机制至关重要且及时。在这里，我们绘制了缺氧水生区 MOB 的全球分布，并总结了 MOB 在缺氧条件下的四种潜在代谢策略：(a) 与好氧微生物形成联合体；(b) MOB 自身产生/储存 O；(c) 与使用其他电子受体的非氧合异养细菌形成联合体；和 (d) 使用除 O 以外的其他替代电子受体。最后，我们提出了未来研究的方向。本研究呼吁提高对缺氧条件下 MOB 的理解，并强调了在全球水生缺氧过程中这一被忽视的 CH 汇的重要性。
