Reviews and syntheses: Contribution of sulfate to aerobic methane oxidation in upland soils – a mini-review

Abstract. Methane (CH4) is a potent greenhouse gas, and its global warming potential is 28 times higher than carbon dioxide (CO2). Various environmental factors influence aerobic CH4 oxidation in soil. The sulfate (SO42-) ion is the main component of atmospheric deposition and has been increasing in recent years. It promotes CH4 production and anaerobic CH4 oxidation; however, the impact of SO42- on aerobic CH4 oxidation in soils has not yet been comprehensively summarized. We synthesize current research on the effects of SO42- on aerobic CH4 oxidation, examining both its macroscopic manifestations and microscale pathways. Through a literature review, we found that SO42- enhances aerobic CH4 oxidation by 0 %–42 %; moreover, it has been found that various physicochemical properties and processes in the soil are influenced by the addition of SO42-, which in turn affects aerobic CH4 oxidation. This review enhances our understanding of the role of SO42- in promoting aerobic CH4 oxidation. It lays the foundation for future research with two primary goals: (1) validating these findings by quantifying CH4 flux and aerobic oxidation rates and (2) elucidating the underlying microbial processes through experimental research. Concurrently, the review provides directions for further investigation into the impact of SO42- on aerobic CH4 oxidation.