Tree xylem isotope analysis by mass and laser spectrometry

The use of xylem isotopes is an increasingly commonly used approach in eco-hydrological studies. Carrière et al. [2019] used this dataset to better understand where trees uptakes water under drought condition on a Mediterranean karstic system. Despite this technique is widely used, analytical issues still discussed within user community. We have conducted a number of tests which are relevant to be shared to animate the debate. We show that mass and laser spectrometer analyzes give very similar results for 46 xylem water and 9 drainage water samples. The full dataset (219 samples) shows that the xylem water undergo a deuterium fractionation which make the deuterium data unusable in the current state.

木质部同位素分析在生态水文学研究中的应用正日益普及。Carrière等[2019]借助该数据集，更深入地解析了地中海喀斯特系统内干旱条件下树木的水源获取位置。尽管该技术已得到广泛应用，但用户群体中仍存在诸多有待探讨的分析方法相关问题。我们开展了多项相关测试，愿与学界共享以推动相关讨论的深入开展。针对46份木质部水样本与9份排水水样的质谱与激光光谱分析结果高度一致。完整数据集（共计219个样本）显示，木质部水发生了氘分馏现象，致使当前状态下的氘同位素数据无法正常使用。