摘要
草地生态系统在全球碳循环研究中占有重要地位,目前,碳同位素技术已经被广泛地应用于草地生态系统碳循环研究中。本文阐述了碳同位素在草地土壤有机碳的来源、光合作用产物碳在草地生态系统中的分配、草地土壤有机质的周转及草地土壤呼吸研究方面的应用,重点论述了碳同位素在土壤呼吸方面的应用。应用碳同位素对土壤呼吸进行区分的方法主要包括13C自然丰度法、脉冲标记法、同位素稀释法、模拟根际沉积物法、14CO2动态模型法、根系分泌物洗涤法等。碳同位素技术对草地土壤和根干扰很小,方法相对成熟,为深入研究草地生态系统碳循环提供了巨大潜力。在我国,应用碳同位素方法研究草地生态系统碳循环在土壤有机碳的来源、分配及周转和土壤呼吸区分等方面有进一步研究的必要,也有进一步研究的发展空间。
Study of grassland ecosystem is essential for understanding the allocation of global carbon pool and the global carbon cycle. In this paper, we reviewed briefly the main applications of carbon isotopes in grassland ecosystem the following aspects： the sources of grassland soil organic carbon, the allocation of photosynthesized carbon in grassland, the turnover of soil organic matter and the study of soil respiration. The focus is on the application of carbon isotopes in the study of soil respiration. Soil respiration is a main wav of carbon dioxide flux from soil to atmosphere, so its separation will contribute to the understanding of soil carbon cycle and carbon balance under the condition of global change. Several methods for separating soil respiration by the application of carbon isotopes have been reviewed including： ①^13C natural abundance method, ② pulse labeling methods, ③the isotope dilution method, ④the model rhizodeposition technique, ⑤modeling of ^14CO2 efflux dynamics, ⑥the exudate elution procedure and ⑦the difference method between root-derived 14CO2 and rhizomierobial 14CO2. There is no standard method and criterion for the separation of soil respiration until now. The temperature sensitivity of soil respiration is important for understanding terrestrial carbon cycling. Many studies recently showed that Q10 is a variable related to temperature, moisture and some other factors. Because most of the 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. Carbon isotope techniques involved less disturbance to the soil-plant system than other methods and had great potential in the study of carbon cycle of grassland ecosystem.
出处
《地理科学进展》
CSCD
北大核心
2009年第3期441-448,共8页
Progress in Geography
基金
国家“十一五”支撑计划(No.2006BAJ10B04)
中国科学院地理科学与资源研究所三期创新项目(066U0605SZ)
关键词
碳同位素
草地生态系统
碳循环
土壤呼吸
carbon isotope
grassland ecosystem
carbon cycle
soil respiration
