Inhibition of Methylmercury and Methane Formation by Nitrous Oxide in Arctic Tundra Soil Microcosms
Inhibition of Methylmercury and Methane Formation by Nitrous Oxide in Arctic Tundra Soil Microcosms
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DOI：
10.1021/acs.est.2c09457
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发表时间：
2023-03
影响因子：
11.4
通讯作者：
Lijie Zhang;Yongchao Yin;Yanchen Sun;Xujun Liang;D. E. Graham;E. Pierce;F. Löffler;B. Gu
中科院分区：
文献类型：
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作者：
Lijie Zhang;Yongchao Yin;Yanchen Sun;Xujun Liang;D. E. Graham;E. Pierce;F. Löffler;B. Gu
气候变暖导致永久冻土融化，预计会增加有毒的甲基汞（MeHg）和温室气体[即，甲烷（CH4）、二氧化碳（CO2）和一氧化二氮（N2O）]的形成。一个缩影培养研究与北极苔原土壤超过145天表明，N2O在0.1和1毫米显着抑制微生物甲基汞的形成，甲烷，硫酸盐还原，而它略有促进CO2的生产。微生物群落分析表明，N2O降低了产甲烷古菌和硫酸盐还原和甲基汞形成的微生物分支的相对丰度。耗尽N2O后，甲基汞的形成和硫酸盐还原迅速恢复，而CH4的生产仍然很低，这表明N2O影响敏感的微生物公会不同。甲基汞的形成与硫酸盐的还原密切相关，这支持了先前将硫酸盐还原菌与北极土壤中的甲基汞形成联系起来的报告。这项研究突出了复杂的地球化学相互作用，在管理甲基汞和甲烷的形成，并奠定了基础，为今后的机制研究，以提高预测了解甲基汞和温室气体通量从解冻冻土生态系统。
Climate warming causes permafrost thaw predicted to increase toxic methylmercury (MeHg) and greenhouse gas [i.e., methane (CH4), carbon dioxide (CO2), and nitrous oxide (N2O)] formation. A microcosm incubation study with Arctic tundra soil over 145 days demonstrates that N2O at 0.1 and 1 mM markedly inhibited microbial MeHg formation, methanogenesis, and sulfate reduction, while it slightly promoted CO2 production. Microbial community analyses indicate that N2O decreased the relative abundances of methanogenic archaea and microbial clades implicated in sulfate reduction and MeHg formation. Following depletion of N2O, both MeHg formation and sulfate reduction rapidly resumed, whereas CH4 production remained low, suggesting that N2O affected susceptible microbial guilds differently. MeHg formation strongly coincided with sulfate reduction, supporting prior reports linking sulfate-reducing bacteria to MeHg formation in the Arctic soil. This research highlights complex biogeochemical interactions in governing MeHg and CH4 formation and lays the foundation for future mechanistic studies for improved predictive understanding of MeHg and greenhouse gas fluxes from thawing permafrost ecosystems.