INFLUENCE OF DIFFERENT ACID TREATMENTS ON THE RADIOCARBON CONTENT SPECTRUM OF SEDIMENTARY ORGANIC MATTER DETERMINED BY RPO/ACCELERATOR MASS SPECTROMETRY
INFLUENCE OF DIFFERENT ACID TREATMENTS ON THE RADIOCARBON CONTENT SPECTRUM OF SEDIMENTARY ORGANIC MATTER DETERMINED BY RPO/ACCELERATOR MASS SPECTROMETRY
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DOI：
10.1017/rdc.2018.125
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发表时间：
2019-04-01
期刊：
影响因子：
8.3
通讯作者：
Eglinton, Timothy, I
中科院分区：
文献类型：
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作者：
Bao, Rui;McNichol, Ann P.;Eglinton, Timothy, I
在实践中，获得沉积物中有机质（OM）的放射性碳（C-14）组成需要首先通过酸处理去除无机碳（IC）。两种常用的处理方法是酸洗和熏蒸。通过不同方法获得的C-14含量可能不同，但这些差异的根本原因仍然难以捉摸。为了评估不同酸处理对沉积有机质中C-14含量的影响，我们研究了一系列海洋和河流沉积物中C-14含量的变化。通过比较未酸化和酸化沉积物[HCl冲洗（冲洗（HCl））和HCl熏蒸（烟雾（HCl））]的结果，我们证明了两种酸处理可以影响C-14含量差异。我们的研究结果表明，对于低碳酸盐样品，冲洗（盐酸）影响Fm值由于年轻的不稳定的有机碳（OC）的损失。烟气（HCl）使不稳定OC的Fm值降低，使残留OC老化。高碳酸盐样品在冲洗（HCl）过程中会损失相对较老的有机组分，导致剩余OC的Fm值增加。烟雾（HCl）可以去除热不稳定的，通常是年轻的，OC和降低Fm值。我们建议使用酸去除沉积物中的碳酸盐时，应考虑三个因素：IC丰度，不稳定和难降解OC的比例，和环境基质。
In practice, obtaining radiocarbon (C-14) composition of organic matter (OM) in sediments requires first removing inorganic carbon (IC) by acid-treatment. Two common treatments are acid rinsing and fumigation. Resulting C-14 content obtained by different methods can differ, but underlying causes of these differences remain elusive. To assess the influence of different acid-treatments on C-14 content of sedimentary OM, we examine the variability in C-14 content for a range of marine and river sediments. By comparing results for unacidified and acidified sediments [HCl rinsing (Rinse(HCl)) and HCl fumigation (Fume(HCl))], we demonstrate that the two acid-treatments can affect C-14 content differentially. Our findings suggest that, for low-carbonate samples, Rinse(HCl) affects the Fm values due to loss of young labile organic carbon (OC). Fume(HCl) makes the Fm values for labile OC decrease, leaving the residual OC older. High-carbonate samples can lose relatively old organic components during Rinse(HCl), causing the Fm values of remaining OC to increase. Fume(HCl) can remove thermally labile, usually young, OC and reduce the Fm values. We suggest three factors should be taken into account when using acid to remove carbonate from sediments: IC abundance, proportions of labile and refractory OC, and environmental matrix.