Wetland drying increases the temperature sensitivity of soil respiration

Hydrological changes during wetland drying alter soil oxidation-reduction (redox) conditions such that soil organic carbon (SOC) decomposition is affected, which may influence global climate-carbon feedbacks. This study aimed to explore whether the temperature sensitivity of soil respiration is affected by changes in soil redox status. We created a gradient of redox potential in wetland soils by adjusting soil moisture content and O2 concentration in microcosms, and incubated these soils under changing temperature to estimate the temperature sensitivity (indicated by Q10) of soil respiration. Our results showed that Q10 values under aerobic conditions were 1.5-2.5 times higher than those under anaerobic incubations, with a significant positive correlation between Q10 and soil redox potential. This study suggested that SOC decomposition through soil respiration during progressive wetland drying may be increasingly sensitive to global warming, which may accelerate SOC loss from wetlands in the future.