The use of stable isotopes to study ecosystem gas exchange
The use of stable isotopes to study ecosystem gas exchange
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DOI：
10.1007/s004420051016
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发表时间：
2000-05
期刊：
影响因子：
2.7
通讯作者：
D. Yakir;L. Sternberg
中科院分区：
文献类型：
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作者：
D. Yakir;L. Sternberg
稳定同位素是环境科学中的一种强有力的研究工具，在生态系统研究中的应用越来越多。在这篇综述中，我们介绍和讨论的相关细节使用的碳和氧同位素组成的生态系统气体交换研究。重点介绍了稳定同位素测量技术的应用现状和发展趋势，以及CO2和水汽的浓度和通量测量技术。对于这些应用，关键是要知道特定的生态系统组件的同位素身份，如CO2的同位素组成，有机质，液态水，水蒸气，以及相关的同位素分馏，在土壤-植物-大气系统。通过使用“基林图”，将稳定同位素和浓度测量相结合是非常有效的。这种方法可以确定同位素组成和生态系统或生态系统组成部分对与大气交换通量的贡献。它还允许估计净生态系统歧视和土壤不平衡效应。最近修改的Keeling情节的方法允许检查CO2在生态系统中的循环。将稳定同位素与动态通量测量相结合需要同位素取样和分析的精确度，而这一点目前处于检测极限。结合微气象梯度法（适用于草地和农田），稳定同位素测量允许分离净CO2交换到光合和土壤呼吸组件，和蒸散通量到土壤蒸发和叶片蒸腾。与涡流相关技术（适用于森林，除了草地和农田）结合使用的类似应用程序要求更高，但可以与基林地块关系结合使用。利用稳定同位素测量的进展和潜力应使其成为有限的生态系统规模研究工具库的标准组成部分。
Stable isotopes are a powerful research tool in environmental sciences and their use in ecosystem research is increasing. In this review we introduce and discuss the relevant details underlying the use of carbon and oxygen isotopic compositions in ecosystem gas exchange research. The current use and potential developments of stable isotope measurements together with concentration and flux measurements of CO2and water vapor are emphasized. For these applications it is critical to know the isotopic identity of specific ecosystem components such as the isotopic composition of CO2, organic matter, liquid water, and water vapor, as well as the associated isotopic fractionations, in the soil-plant- atmosphere system. Combining stable isotopes and concentration measurements is very effective through the use of ”Keeling plots.” This approach allows the identification of the isotopic composition and the contribution of ecosystem, or ecosystem components, to the exchange fluxes with the atmosphere. It also allows the estimation of net ecosystem discrimination and soil disequilibrium effects. Recent modifications of the Keeling plot approach permit examination of CO2recycling in ecosystems. Combining stable isotopes with dynamic flux measurements requires precision in isotopic sampling and analysis, which is currently at the limit of detection. Combined with the micrometeorological gradient approach (applicable mostly in grasslands and crop fields), stable isotope measurements allow separation of net CO2exchange into photosynthetic and soil respiration components, and the evapotranspiration flux into soil evaporation and leaf transpiration. Similar applications in conjunction with eddy correlation techniques (applicable to forests, in addition to grasslands and crop fields) are more demanding, but can potentially be applied in combination with the Keeling plot relationship. The advance and potential in using stable isotope measurements should make their use a standard component in the limited arsenal of ecosystem-scale research tools.