PubMed · 2026-04-06
Scientists discovered that reactive oxygen species (ROS) — unstable molecules formed when oxygen reacts with organic matter — can chemically produce methane in wetland soils without any microbes involved. This abiotic pathway is triggered by fluctuating water levels and is amplified by iron chemistry and organic materials like decomposing fish and plant litter.
A clear linear relationship was found between hydroxyl radical accumulation and methane production: every 1 nmol/L of hydroxyl radicals yielded 91 nmol/L of methane across 14 Chinese wetland soils.
Natural organic materials — specifically fish remains and rice litter — acted as methane 'hotspots,' accounting for roughly 50% of total methane emissions during oxygenation events.
Iron chelation and soil acidification together enhance this abiotic methane pathway by keeping iron dissolved and available to drive the reaction, rather than precipitating out of solution.
