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<p>Thermokarst lakes represent a critical source of atmospheric methane (CH<sub>4</sub>), owing to large amounts of microbially generated CH<sub>4</sub> in sediments. However, the structure and function of lake sediment microbiota, as well as their roles in mediating CH<sub>4</sub> production, remain poorly understood across broad geographic scales. Here, we combined high-throughput sequencing, a 224-d anaerobic incubation, and stable isotopic analyses to investigate sediment microbiota and CH<sub>4</sub> production across 30 thermokarst lakes along a 1,100 km permafrost transect on the Tibetan Plateau. Our results revealed that lake characteristics (i.e., lake depth and salinity-alkalinity) shaped sediment microbial composition and function. Deeper lakes exhibited enriched methanogenic taxa and pathways. In contrast, shallower lakes with higher salinity-alkalinity were dominated by microbial consortia that suppress net CH<sub>4</sub> production via methanotrophs consuming CH<sub>4</sub> and sulfate reducers competing with acetoclastic and hydrogenotrophic methanogens. Accordingly, cumulative CH<sub>4</sub> production decreased by one order of magnitude from deeper lakes (2.5 log<sub>10</sub>CH<sub>4</sub>-C µg/g) to shallow and alkaline lakes (1.3 log<sub>10</sub>CH<sub>4</sub>-C µg/g) or salinity-alkalinity lakes (1.1 log<sub>10</sub>CH<sub>4</sub>-C µg/g). This variation was modulated by both key microbial consortia and sediment organic carbon and nitrogen supply. Overall, these results disentangled how lake characteristics restructured microbial dynamics to alter sediment CH<sub>4</sub> production, and identified critical microbial consortia that could predict spatial variations in sediment CH<sub>4</sub> production across thermokarst lakes.</p>

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Microbial community structure and function and their linkages with methane production in sediments of thermokarst lakes on the Tibetan Plateau

  • 期刊论文

  • 发表日期：

    2026年6月29日

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  • Yutong Song,
  • Chao Mao,
  • Pengfei Liu,
  • Guibiao Yang,
  • Luyao Kang,
  • Ziliang Li,
  • Wei Zhou,
  • Xuning Liu,
  • Shiting Yao,
  • Yuanhe Yang

摘要

Thermokarst lakes represent a critical source of atmospheric methane (CH4), owing to large amounts of microbially generated CH4 in sediments. However, the structure and function of lake sediment microbiota, as well as their roles in mediating CH4 production, remain poorly understood across broad geographic scales. Here, we combined high-throughput sequencing, a 224-d anaerobic incubation, and stable isotopic analyses to investigate sediment microbiota and CH4 production across 30 thermokarst lakes along a 1,100 km permafrost transect on the Tibetan Plateau. Our results revealed that lake characteristics (i.e., lake depth and salinity-alkalinity) shaped sediment microbial composition and function. Deeper lakes exhibited enriched methanogenic taxa and pathways. In contrast, shallower lakes with higher salinity-alkalinity were dominated by microbial consortia that suppress net CH4 production via methanotrophs consuming CH4 and sulfate reducers competing with acetoclastic and hydrogenotrophic methanogens. Accordingly, cumulative CH4 production decreased by one order of magnitude from deeper lakes (2.5 log10CH4-C µg/g) to shallow and alkaline lakes (1.3 log10CH4-C µg/g) or salinity-alkalinity lakes (1.1 log10CH4-C µg/g). This variation was modulated by both key microbial consortia and sediment organic carbon and nitrogen supply. Overall, these results disentangled how lake characteristics restructured microbial dynamics to alter sediment CH4 production, and identified critical microbial consortia that could predict spatial variations in sediment CH4 production across thermokarst lakes.