Accelerating electron transfer reduces CH₄ and CO₂ emissions in paddy soil.

Area of Science:

• Environmental Science
• Microbiology
• Soil Science

Background:

• Greenhouse gas emissions from soil, particularly CO2 and CH4, are significant environmental concerns.
• Microbial electrochemical technologies, such as microbial electrochemical snorkels (MES), offer potential for influencing soil biogeochemical processes.
• The impact of MES on soil greenhouse gas production, especially methane and CO2, requires further investigation.

Purpose of the Study:

• To investigate the effect of microbial electrochemical snorkels (MES) on soil greenhouse gas production (CO2, CH4, N2O).
• To elucidate the microbial mechanisms underlying changes in greenhouse gas emissions induced by MES.
• To evaluate MES as a strategy for mitigating greenhouse gas emissions in paddy soils.

Main Methods:

• Application of microbial electrochemical snorkel (MES) in paddy soil.
• Measurement of cumulative CO2, CH4, and N2O emissions.
• Quantification of Fe2+ content.
• Analysis of microbial community structure and abundance (methanogens).
• Assessment of genes involved in methanogenesis pathways.

Main Results:

• MES treatment comparable N2O emissions to control but reduced cumulative CO2 by 50% and CH4 by 41%.
• Increased Fe2+ content in MES treatment promoted iron reduction, competing with methanogenesis.
• MES decreased methanogen abundance by 19-20% due to competition among microbial groups.
• MES reduced genes for hydrogenotrophic and acetoclastic methanogenesis, inhibiting CH4 production.

Conclusions:

• Accelerated electron transfer via MES significantly reduces CO2 and CH4 emissions from paddy soil.
• MES influences soil greenhouse gas dynamics by altering microbial competition and inhibiting methanogenesis pathways.
• MES presents a novel and effective strategy for mitigating greenhouse gas emissions in agricultural soils.