Reji Linta, Duan Jianshu, Myneni Satish C B, Zhang Xinning
Department of Geosciences, Princeton University, Princeton, NJ 08544, United States.
High Meadows Environmental Institute, Princeton University, Princeton, NJ 08544, United States.
ISME Commun. 2025 Apr 14;5(1):ycaf063. doi: 10.1093/ismeco/ycaf063. eCollection 2025 Jan.
Hydrological shifts in wetlands, a globally important methane (CH) source, are critical constraints on CH emissions and carbon-climate feedbacks. A limited understanding of how hydrologically driven oxygen (O) variability affects microbial CH cycling in diverse wetlands makes wetland CH emissions uncertain. Transient O exposure significantly stimulated anoxic CH production in incubations of peat from a temperate bog by enriching for polyphenol oxidizers and polysaccharide degraders, enhancing substrate flow toward methanogenesis under subsequent anoxic conditions. To assess whether shifts in soil microbiome structure and function operate similarly across wetland types, here we examined the sensitivity of different wetland soils to transient oxygenation. In slurry incubations of peat from a minerotrophic fen, and sediments from a freshwater marsh and saltmarsh, we examined temporal shifts in microbiomes coupled with geochemical characterization of slurries and incubation headspaces. Oxygenation did not affect microbiome structure and anoxic CH production in mineral-rich fen-origin peat and freshwater marsh soils. Key taxa linked to O-stimulated CH production in the bog-origin peat were notably rare in the fen-origin peat, supporting microbiome structure as a primary determinant of wetland response to O shifts. In contrast to freshwater wetland experiments, saltmarsh geochemistry-particularly pH-and microbiome structure were persistently and significantly altered postoxygenation, albeit with no significant impact on greenhouse gas emissions. These divergent responses suggest wetlands may be differentially resistant to O fluctuations. With climate change driving greater O variability in wetlands, our results inform mechanisms of wetland resistance and highlight microbiome structure as a potential resiliency biomarker.
湿地是全球重要的甲烷（CH）源，其水文变化是CH排放和碳 - 气候反馈的关键制约因素。对水文驱动的氧气（O）变化如何影响不同湿地中微生物CH循环的了解有限，这使得湿地CH排放具有不确定性。短暂暴露于O显著刺激了温带沼泽泥炭培养物中的缺氧CH生成，通过富集多酚氧化酶和多糖降解酶，在随后的缺氧条件下增强了底物向甲烷生成的流动。为了评估土壤微生物群落结构和功能的变化在不同湿地类型中是否具有相似的作用，我们在此研究了不同湿地土壤对短暂氧化的敏感性。在对富矿营养型沼泽泥炭、淡水沼泽沉积物和盐沼沉积物进行的泥浆培养中，我们研究了微生物群落的时间变化以及泥浆和培养顶空的地球化学特征。氧化对富矿营养型沼泽起源泥炭和淡水沼泽土壤中的微生物群落结构和缺氧CH生成没有影响。与沼泽起源泥炭中与O刺激的CH生成相关的关键分类群在富矿营养型沼泽起源泥炭中明显稀少，这支持了微生物群落结构是湿地对O变化响应的主要决定因素。与淡水湿地实验不同，盐沼的地球化学——特别是pH值——和微生物群落结构在氧化后持续且显著改变，尽管对温室气体排放没有显著影响。这些不同的反应表明湿地对O波动的抗性可能存在差异。随着气候变化导致湿地中O的变化更大，我们的结果揭示了湿地抗性机制，并突出了微生物群落结构作为潜在恢复力生物标志物的作用。
