Inhibition of Methylmercury and Methane Formation by Nitrous Oxide in Arctic Tundra Soil Microcosms
Climate warming causes permafrost thaw predicted to increase toxic methylmercury (MeHg) and greenhouse gas [i.e., methane (CH 4 ), carbon dioxide (CO 2 ), and nitrous oxide (N 2 O)] formation. A microcosm incubation study with Arctic tundra soil over 145 days demonstrates that N 2 O at 0.1 and 1 mM...
| Published in: | Environmental Science & Technology |
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| Main Authors: | , , , , , , , |
| Language: | unknown |
| Published: |
2023
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| Subjects: | |
| Online Access: | http://www.osti.gov/servlets/purl/1968707 https://www.osti.gov/biblio/1968707 https://doi.org/10.1021/acs.est.2c09457 |
| Summary: | Climate warming causes permafrost thaw predicted to increase toxic methylmercury (MeHg) and greenhouse gas [i.e., methane (CH 4 ), carbon dioxide (CO 2 ), and nitrous oxide (N 2 O)] formation. A microcosm incubation study with Arctic tundra soil over 145 days demonstrates that N 2 O at 0.1 and 1 mM markedly inhibited microbial MeHg formation, methanogenesis, and sulfate reduction, while it slightly promoted CO 2 production. Microbial community analyses indicate that N 2 O decreased the relative abundances of methanogenic archaea and microbial clades implicated in sulfate reduction and MeHg formation. Following depletion of N 2 O, both MeHg formation and sulfate reduction rapidly resumed, whereas CH 4 production remained low, suggesting that N 2 O 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. Here, this research highlights complex biogeochemical interactions in governing MeHg and CH 4 formation and lays the foundation for future mechanistic studies for improved predictive understanding of MeHg and greenhouse gas fluxes from thawing permafrost ecosystems. |
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