Are ecological gradients in seasonal Q10 of soil respiration explained by climate or by vegetation seasonality
Are ecological gradients in seasonal Q10 of soil respiration explained by climate or by vegetation seasonality
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DOI：
10.1016/j.soilbio.2010.06.008
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发表时间：
2010-10
影响因子：
9.7
通讯作者：
Xuhui Wang;S. Piao;P. Ciais;I. Janssens;M. Reichstein;S. Peng;Tao Wang
中科院分区：
文献类型：
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作者：
Xuhui Wang;S. Piao;P. Ciais;I. Janssens;M. Reichstein;S. Peng;Tao Wang
土壤呼吸对未来气候变化特别是全球变暖高度敏感。然而，相当大的不确定性仍然与SR及其控制过程的温度敏感性。本研究使用来自114篇已发表论文和一本书的384个实地测量数据，量化了土壤呼吸的季节性Q10值的变化，温度升高10°C时呼吸速率增加的乘数，以及不同地点的驱动因素。Q10和年均温度或年均降水量之间没有显着的相关性时，发现统计控制植被活动的季节性变化，推导出卫星植被绿度指数观测（归一化差异植被指数，或NDVI）。与此相反，植被指数的季节变化幅度与SR的表观Q10呈显著正相关，表明不同地点的季节性植被活动变化对SR表观Q10的变化起主导作用，突出了植物生理过程与土壤过程之间的生态联系。这进一步意味着，植被活动的季节性变化可能因此主导了明显的季节性温度敏感性。结果表明，土壤有机质分解的表观Q10值一般大于土壤有机质分解的温度敏感性，直接应用于生态系统模型时应注意。我们的回归分析进一步表明，当NDVI的变化幅度接近0（因此，当植被活动的季节性是边际），残差Q10的SR土壤温度测量在5cm深度约为1.5。
Soil respiration (SR) is highly sensitive to future climate change, and particularly to global warming. However, considerable uncertainties remain associated with the temperature sensitivity of SR and its controlling processes. Using 384 field measurement data from 114 published papers and one book, this study quantifies the variation in the seasonal Q10values of soil respiration, the multiplier by which respiration rates increase for a 10°C increase in temperature, and its drivers across different sites. No significant correlation between Q10and mean annual temperature or mean annual precipitation is found when statistically controlling seasonal changes in vegetation activity, deduced from satellite vegetation greenness index observations (normalized difference vegetation index, or NDVI). In contrast, the seasonal amplitude of NDVI is significantly and positively correlated with the apparent Q10of SR. This result indicates that the variations of seasonal vegetation activity exert dominant control over the variations of the apparent Q10of SR across different sites, highlighting the ecological linkage between plant physiological processes and soil processes. It further implies that the seasonal variation of vegetation activity may thus dominate the apparent seasonal temperature sensitivity. We conclude that the apparent Q10value of SR estimated from field measurements is generally larger than the intrinsic temperature sensitivity of soil organic matter decomposition, and thus cautions should be taken when applying apparent Q10values directly in ecosystem models. Our regression analysis further shows that when the amplitude of NDVI variation approximates 0 (and thus when the seasonality in vegetation activity is marginal), the residual Q10of SR for soil temperature measured at 5cm depth is about 1.5.