Microbial Reduction of Methane Emissions from High-Altitude Thermokarst Lakes.

Authors

Mei Mu, Cuicui Mu, Hebin Liu, Jinyue Song, Xinlong Du, Yongqi Ge, Pengsi Lei, Xiaoxiao Mo, Yuguo Wei, Chunling Zhang, Changming Zhao

Published in

Environmental science & technology. Jul 21, 2026. Epub Jul 21, 2026.

Abstract

Thermokarst lakes, a typical landscape resulting from abrupt permafrost thaw, are expected to be a substantial CH₄ source. Climate change perturbs CH₄ dynamics in these systems, particularly through increasingly frequent wet-dry cycles in small thermokarst lakes. However, how wet-dry alternation alters microbial communities remains poorly understood, and quantifying the effects of microbial shifts on CH₄ emissions from these lakes represents a key challenge. Here, by integrating field observations, laboratory incubation experiments, and amplicon sequencing, we show that seasonal thermokarst lakes with wet-dry alternation exhibit a 41-70% decrease in diffusive CH₄ emissions compared with perennial lakes. Alternating wet-dry cycles lead to a 33-37% decrease in the relative abundances of methanogens and a 39-59% decline in syntrophic partners in lake sediments, while the anaerobic methanotrophic archaea Candidatus Methanoperedens increased from 0.2% to 20.8%. Functional gene analyses indicate acetoclastic methanogenesis, dominated by Methanosaeta, is the primary pathway of CH₄ production. The reduction in CH₄ emissions is associated with changes in sediment properties, as well as decreased abundances of methylotrophic Methanomassiliicoccaceae and syntrophs. Moreover, denitrifying anaerobic CH₄ oxidation processes mediated by Candidatus Methanoperedens lead to a further decline in CH₄ emissions. This study provides novel insights into the microbial changes and pathways regulating diffusive CH₄ emissions from seasonal thermokarst lakes, which is crucial for assessing permafrost carbon-climate feedback and prioritizing CH₄ mitigation strategies.

PMID:
42478355
Bibliographic data and abstract were imported from PubMed on 21 Jul 2026.

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