Plant source water apportionment using stable isotopes: A comparison of simple linear, two-compartment mixing model approaches
Plant source water apportionment using stable isotopes: A comparison of simple linear, two-compartment mixing model approaches
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DOI：
10.1002/hyp.11233
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发表时间：
2017-10-01
影响因子：
3.2
通讯作者：
Clemens, John
中科院分区：
文献类型：
--
作者：
Evaristo, Jaivime;McDonnell, Jeffrey J.;Clemens, John
利用稳定同位素识别植物源水是生态水文过程研究中的一种常用方法。尽管如此，很少有关键的评价的方法进行了源解析。在这里，我们提出了一个关键的评价的主要方法用于包气带和饱和带水之间的源解析：简单的质量平衡和贝叶斯混合模型。我们利用新西兰基督城植物园的一组不同树种的新同位素干水样本，这些树种的地形和土壤条件非常均匀。我们的研究结果表明，单独使用三角洲H-2在一个简单的，两个源的质量平衡的方法会导致错误的结果，特别是一个明显的高估地下水对木质部的贡献。或者，在贝叶斯推理框架中使用δ H-2和δ O-18可以改善水源水估计，比简单的质量平衡方法更有用，特别是当土壤和地下水的贡献相对不成比例时。我们建议，植物源水的定量方法应考虑到H-2/H-1分馏的可能影响。这里使用的贝叶斯推断方法可能比简单的质量平衡方法对H-2/H-1分馏效应不太敏感。
Plant source water identification using stable isotopes is now a common practice in ecohydrological process investigations. Notwithstanding, little critical evaluation of the approaches for source apportionment have been conducted. Here, we present a critical evaluation of the main methods used for source apportionment between vadose and saturated zone water: simple mass balance and Bayesian mixing models. We leverage new isotope stem water samples from a diverse set of tree species in a strikingly uniform terrain and soil conditions at the Christchurch Botanic Garden, New Zealand. Our results show that using delta H-2 alone in a simple, two-source mass balance approach leads to erroneous results, particularly an apparent overestimation of groundwater contribution to xylem. Alternatively, using both delta H-2 and delta O-18 in a Bayesian inference framework improves the source water estimates and is more useful than the simple mass balance approach, particularly when soil and groundwater contributions are relatively disproportionate. We suggest that plant source water quantification methods should take into consideration the possible effects of H-2/H-1 fractionation. The Bayesian inference approach used here may be less sensitive to H-2/H-1 fractionation effects than simple mass balance methods.