Redox-driven changes in water-dispersible colloids and their role in carbon cycling in hydromorphic soils

Abstract Redox fluctuations in hydromorphic soils can influence ecosystem functions by altering the cycling of organic carbon (OC) and other elements in both the aqueous and solid phases throughout the soil profile. Most studies focusing on the mobility of dissolved OC in rice paddy soils have often disregarded the contribution of colloidal particles. We provide a detailed chemical and size-related characterization of water-dispersible soil colloids and their depth distribution in two soil profiles under long-term temperate paddy and non-paddy management, by asymmetric flow field-flow fractionation. Anoxic conditions enhanced colloid dispersion with a preferential release of the finer colloid fractions (5 and 4-fold increase in the