土壤呼吸的温度敏感性  

The Temperature Sensitivity of Soil Respiration

作　　者：刘洪升[1] 刘华杰[2] 王智平[3] 徐明[1] 韩兴国[3] 李凌浩[3] 

机构地区：[1]中国科学院地理科学与资源研究所生态系统网络观测与模拟重点实验室,北京100101 [2]河北大学生命科学学院,保定071002 [3]中国科学院植物研究所植被与环境变化重点实验室,北京100093

出　　处：《地理科学进展》2008年第4期51-60,共10页Progress in Geography

基　　金：国家自然科学基金(30500067);国家自然科学基金创新群体项目(30521002)

摘　　要：土壤呼吸是指土壤释放CO2的过程,它所释放出的CO2是生物圈向大气圈释放CO2的主要来源之一。土壤呼吸速率对温度变化的敏感性是陆地生态系统碳循环过程中一个十分重要的环节。由于许多大尺度碳循环模型中都涉及土壤呼吸的温度敏感性这一问题,因此对该问题的回答有助于提高对当前陆地生态系统碳通量的估算和对未来气候变化预测的准确性。本文就目前土壤呼吸速率对温度变化的敏感性的主要问题进行了综述,从温度、水分、呼吸底物的数量和质量、酶促反应动力学等几个不同的方面,概述了土壤呼吸温度敏感性的变异范围较大的原因,以及这些因素对土壤呼吸的温度敏感性影响的机理。土壤呼吸是酶促的化学反应,因此其温度敏感性不仅取决于呼吸底物的质量,同样也取决于底物的有效性。A growing body of literature sheds new light on the importance of the temperature sensitivity （Q10） of soil respiration for understanding terrestrial carbon cycling. It has been well known that small changes in Q10 value will have great influence on soil CO2 efflux, due to its nonlinear response to temperature. Because most of large-scale carbon cycle models are based on the temperature sensitivity, the accurate determination of Q10 value is essential in estimating carbon efflux in terrestrial ecosystems and predicting future climate change. Unfortunately, this value remains uncertain yet. A fixed Q10 of 2.0 has been widely used in modeling leaf-to ecosystem-scale respiration responses to temperature, until several recent studies suggest that Q10 value is not constant during a year, but tends to decrease with increasing temperature and decreasing soil moisture. A fixed Q10 used in empirical or processes-based models, therefore, can result in a greatly over-or under-estimated soil respiration, due to the variability of Q10 value. More insight information in the relationship between Q10 and controlling factors is vital for accurately estimating soil respiration and for developing management strategies to improve soil fertility and to increase C sequestration in soil. In this paper, we reviewed recent advances and hotspots in Q10 research, especially focused on the responses of resistant and labile carbon to temperature. We further reviewed why Q10 value is so variable and explained this phenomenon based on the Michaelis-Menten kinetics. In addition, we reviewed how soil temperature and moisture influence substrate availability and enzymes activity and hence influence temperature sensitivity of soil respiration.

关 键 词：土壤呼吸 温度敏感性 温度 底物有效性 酶 

分 类 号：S154[农业科学—土壤学]