Photosynthetic carbon isotope discrimination and its relationship to the carbon isotope signals of stem, soil and ecosystem respiration.
Photosynthetic carbon isotope discrimination and its relationship to the carbon isotope signals of stem, soil and ecosystem respiration.
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DOI：
10.1111/j.1469-8137.2010.03384.x
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发表时间：
2010-10
期刊：
影响因子：
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通讯作者：
L. Wingate;J. Ogée;R. Burlett;A. Bosc;M. Devaux;J. Grace;D. Loustau;A. Gessler
中科院分区：
文献类型：
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作者：
L. Wingate;J. Ogée;R. Burlett;A. Bosc;M. Devaux;J. Grace;D. Loustau;A. Gessler
·光合碳（C）同位素鉴别（Δ（A））在波动的环境条件期间用可变的C同位素组成标记光合产物（δ（A））和大气CO（2）（δ（a））。在这种情况下，生态系统内呼吸的CO（2）的C同位素组成通常被假设为随Δ（A）而随时间变化。·利用新型可调谐二极管激光吸收光谱仪，在一个成熟的海洋松林中研究了Δ（A）与树干（δ（W））、土壤（δ（S））和生态系统（δ（E））中的碳同位素信号之间的关系。·Δ（A）的广泛季节性变化反映在δ（W）、δ（S）和δ（E）中。然而，呼吸CO（2）信号的短期变化比Δ（A）小，并且偏移和延迟2-10 d，表明在大的C库中存在分馏和同位素混合。δ（S）的变化并不总是跟随Δ（A），特别是在雨季和地面上对C分配有强烈需求的时候。未来的同位素植被模型可能需要开发能够解释这些现象的传递函数，以便解释和预测生物圈气体交换对大气CO（2）的C同位素组成的同位素影响。
• Photosynthetic carbon (C) isotope discrimination (Δ(Α)) labels photosynthates (δ(A) ) and atmospheric CO(2) (δ(a)) with variable C isotope compositions during fluctuating environmental conditions. In this context, the C isotope composition of respired CO(2) within ecosystems is often hypothesized to vary temporally with Δ(Α). • We investigated the relationship between Δ(Α) and the C isotope signals from stem (δ(W)), soil (δ(S)) and ecosystem (δ(E)) respired CO(2) to environmental fluctuations, using novel tuneable diode laser absorption spectrometer instrumentation in a mature maritime pine forest. • Broad seasonal changes in Δ(Α) were reflected in δ(W,) δ(S) and δ(E). However, respired CO(2) signals had smaller short-term variations than Δ(A) and were offset and delayed by 2-10 d, indicating fractionation and isotopic mixing in a large C pool. Variations in δ(S) did not follow Δ(A) at all times, especially during rainy periods and when there is a strong demand for C allocation above ground. • It is likely that future isotope-enabled vegetation models will need to develop transfer functions that can account for these phenomena in order to interpret and predict the isotopic impact of biosphere gas exchange on the C isotope composition of atmospheric CO(2).