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

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).本研究采用全因子增温与降水调控实验，探究胞外酶（extracellular enzymes, EEs）动力学的响应与驯化过程，并通过对比恒定动力学参数与温度敏感动力学参数两种方案的经验数学模型，进一步解析土壤有机质分解动态。研究结果显示，气候变化情景下胞外酶动力学普遍出现降低，其中增温与降水调控协同处理下的下降幅度尤为显著。本研究在多种气候处理组中均观测到温度敏感性（以Q₁₀表征）发生显著变化，不过这些响应模式呈现出明确的酶特异性差异。模型模拟结果表明，相较于采用温度敏感动力学参数的表征方式，使用恒定动力学参数会显著高估土壤有机质分解动态，这可能会高估升温与温室气体（如CO₂）排放之间的正反馈效应。