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土壤呼吸温度敏感性的影响因素和不确定性
引用本文:杨庆朋,徐明,刘洪升,王劲松,刘丽香,迟永刚,郑云普.土壤呼吸温度敏感性的影响因素和不确定性[J].生态学报,2011,31(8):2301-2311.
作者姓名:杨庆朋  徐明  刘洪升  王劲松  刘丽香  迟永刚  郑云普
作者单位: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;中国科学院研究生院,北京,100049
2. 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
3. 郴州市苏仙区林业局,湖南,郴州,432000
基金项目:国家自然科学基金项目(面上项目,重点项目,重大项目)
摘    要:土壤呼吸是陆地生态系统碳循环的重要环节之一, 其对温度升高的敏感程度在很大程度上决定着全球气候变化与碳循环之间的反馈关系。为了深刻理解地下生态过程对气候变化的响应和适应,本文综述了土壤呼吸温度敏感性(Q10)的影响因子及其内在机制,并分析了当前研究存在的不确定性。土壤生物、底物质量和底物供应显著调控着土壤呼吸的Q10值,但研究结论仍然有很大差异。温度和水分等环境因子则通过对土壤生物和底物的影响而作用于土壤呼吸的温度敏感性,一般情况下,随着温度的升高,土壤呼吸的Q10值下降;水分过高或过低时Q10值降低。另外本文从土壤温度测定深度、时空尺度、土壤呼吸不同组分温度敏感性差异、激发效应以及采用方法的不同等几方面分析了温度敏感性研究存在的不确定性。并在此基础上, 指出了未来拟重点加强的研究方向:(1)土壤呼吸不同组分温度敏感性差异的机理;(2)底物质量和底物供应对温度敏感性的交互影响;(3)生物因子对土壤呼吸温度敏感性的影响。

关 键 词:土壤呼吸  温度敏感性  Q10值  底物供应  底物质量
收稿时间:3/24/2010 9:32:03 AM
修稿时间:1/10/2011 9:23:44 AM

Impact factors and uncertainties of the temperature sensitivity of soil respiration
YANG Qingpeng,XU Ming,LIU Hongsheng,WANG Jinsong,LIU Lixiang,CHI Yonggang and ZHENG Yunpu.Impact factors and uncertainties of the temperature sensitivity of soil respiration[J].Acta Ecologica Sinica,2011,31(8):2301-2311.
Authors:YANG Qingpeng  XU Ming  LIU Hongsheng  WANG Jinsong  LIU Lixiang  CHI Yonggang and ZHENG Yunpu
Institution:Institute of Geographic Science and Natural Resources Research,CAS,
Abstract:Abstract: Soil respiration is one of the most important components of the carbon cycle in terrestrial ecosystems, and its response to temperature change has dramatic effects on the feedback between terrestrial carbon cycle and global warming. Our understanding of the impact of environmental and biological factors on soil respiration has been enhanced greatly recently, however our knowledge on the temperature sensitivity of soil respiration is still very limited. Therefore it is critical to have deeper understanding of the factors that control the temperature sensitivity of soil respiration. In this paper we reviewed the recent studies about the temperature sensitivity of soil respiration. We found that soil organisms, substrate availability and quality had significant effects on the temperature sensitivity of soil respiration, but the results of most studies were incompatible. Activation energy theory suggests that the temperature sensitivity of soil respiration should increase with decreasing substrate quality. However, this hypothesis received dramatic challenge. Based on Michaelis-Menten function, theoretic and experimental results showed that substrate availability had a significant positive effect on temperature sensitivity. Consequently results from previous research indicated that the temperature sensitivity of resistant substrates may be greater than, equivalent to, or less than that of labile substrates. One can not explain the difference among various experiments without taking biological factors into consideration. For example, temperature change has great influence on root biomass, soil microbial population structure and biological diversity, which may alter the response of soil respiration to temperature change. Temperature sensitivity is high when root growth and temperature increasing occurred synchronously. Similarly it will be low when they occurred asynchronously. At ecosystem and regional scales, temperature and moisture were main factors affecting the temperature sensitivity of soil respiration, ie Q10 value negatively and positively related with temperature and moisture, respectively, except for too dry or too wet conditions. In addition, we also compared the literatures and pointed out the sources of uncertainties. Because of the time lag and attenuation, the temperature sensitivity of soil respiration strongly depends on the temperature measuring depth. In order to reduce uncertainties, the effect of varying temperature measurement depth must be considered and most appropriate temperature measurement depth must be selected. Research scales should also be taken into consideration. Since soil respiration measured at various temporal and spatial scales reflect diverse processes, its temperature sensitivity was dominated by different factors. The responses of root respiration and microbial respiration to temperature change may be different, which is also a source of uncertainty. For example, some studies found root respiration was more temperature sensitive than microbial respiration when measured during the course of a year, and this high temperature sensitivity was controlled by substrate supply from photosynthesis, which means the proportion of root respiration to microbial respiration is one of the reasons causing higher variability. Rhizosphere priming effect can also obscure the temperature sensitivity of soil respiration. In fact, the rhizosphere priming effect is of key importance to our understanding of soil respiration, because it means that the total soil respiration is not a simple additive function of soil-derived and plant-derived respiration. Finally, based on our thorough review, three priority areas on temperature sensitivity of soil respiration are proposed as follows: (1) the difference of the temperature sensitivity between root respiration and microbial respiration; (2) interaction effects between substrate quality and substrate availability on the temperature sensitivity; and (3) the influences of biotic factors (plant root and microbial structure) on temperature sensitivity of soil respiration.
Keywords:soil respiration  temperature sensitivity  Q10  substrate availability  substrate quality
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