Constant extracellular enzyme kinetics parameters overestimate soil organic matter decomposition dynamics in a Tibetan alpine grassland: evidence from a decade-long experiment

We implemented full-factorial warming and precipitation manipulations to examine the response and acclimation of extracellular enzymes (EEs) kinetics, and further compared soil organic matter decomposition dynamics using an empirical mathematical model that contrasts constant versus temperature-sensitive EEs kinetics parameters approaches. Our results demonstrate widespread reductions in EEs kinetics under climate change scenarios, with particularly pronounced declines under combined warming and precipitation manipulations. We observed significant changes in temperature sensitivity (expressed by Q10) across multiple climate treatments, though these responses exhibited clear enzyme-specific patterns. Model simulations revealed significant overestimation of soil organic matter decomposition dynamic when using constant kinetic parameters compared to temperature-sensitive representations, which may overestimate the positive feedback between increased temperature and greenhouse gas emission (e.g. CO2).