ISOTOPE EFFECTS ACCOMPANYING VACUUM EXTRACTION OF SOIL-WATER FOR STABLE-ISOTOPE ANALYSES
ISOTOPE EFFECTS ACCOMPANYING VACUUM EXTRACTION OF SOIL-WATER FOR STABLE-ISOTOPE ANALYSES
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DOI：
10.1016/0022-1694(94)02636-p
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发表时间：
1995-06-01
影响因子：
6.4
通讯作者：
LOUVAT, D
中科院分区：
文献类型：
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作者：
ARAGUASARAGUAS, L;ROZANSKI, K;LOUVAT, D
真空蒸馏法提取土壤水进行稳定同位素分析的三种不同类型的土壤进行了测试，其特征在于高含水量：（1）纯砂，（2）具有高有机质含量的形成土，在温带气候条件下发育在石灰质砂岩上（奥地利），和（3）有机质贫乏的热带砖红壤，发育在桑迪粘土沉积物上（巴西）。该方法产生准确和可重复的结果，为砂，提供了超过98%的原始土壤水被提取。完全浸提所需的时间是样本量和所用浸提温度的函数。粘土柱实验表明，存在一个弱结合，容易交换池的水是同位素不同的移动的水。实验表明，当与渗滤液（移动的水）相比时，提取的土壤水的氘和氧-18分别减少5-10份/千和0.3-0.5份/千。这种消耗在很大程度上取决于土壤类型。从粘性土壤中重复提取土壤水的重现性分别约为+/-3ppm和0.3ppm，其中6D和δ（18）O分别为± 3 ppm和0.3ppm。
The vacuum distillation method of extracting soil water for stable isotope analysis was tested for three different types of soil characterized by high water content: (1) pure sand, (2) cambisol with high organic matter content, developed on calcareous sandstone under temperate climatic conditions (Austria), and (3) tropical latosol poor in organic matter, developed on sandy clay sediment (Brazil). The method yields accurate and reproducible results for sand, provided that more than 98% of the original soil water is extracted. The time required for complete extraction is a function of sample size and the applied extraction temperature. Column experiments with the clayey soils revealed existence of a weakly bound, easily exchangeable pool of water which is isotopically different from the mobile water. The experiments showed that the extracted soil water is depleted in both deuterium and oxygen-18 by 5-10 parts per thousand and 0.3-0.5 parts per thousand, respectively, when compared with the percolate (mobile water). This depletion depends strongly on the soil type. The reproducibility for replicate extractions of soil water from clayey soils is around +/-3 parts per thousand and 0.3 parts per thousand for 6D and delta(18)O, respectively.