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

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 (SO₄^2-) 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 SO₄^2- on aerobic CH₄ oxidation in soils has not yet been comprehensively summarized. We synthesize current research on the effects of SO₄^2- on aerobic CH₄ oxidation, examining both its macroscopic manifestations and microscale pathways. Through a literature review, we found that SO₄^2- 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 SO₄^2-, which in turn affects aerobic CH₄ oxidation. This review enhances our understanding of the role of SO₄^2- 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 SO₄^2- on aerobic CH₄ oxidation.