Evaluation of a protocol for the quantification of black carbon in sediments
Evaluation of a protocol for the quantification of black carbon in sediments
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DOI：
10.1029/2000gb001380
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发表时间：
2001-12-01
影响因子：
5.2
通讯作者：
Eglinton, TI
中科院分区：
文献类型：
--
作者：
Gustafsson, Ö;Bucheli, TD;Eglinton, TI
植被火灾和木材燃料燃烧产生的高度浓缩的黑碳（BC）可能会将大气-生物圈循环中快速循环的碳转化为循环速度慢得多的地质形式。最近报道的表层海洋沉积物中总有机碳（TOC）的BC分数范围很广（2-90%），目前尚不清楚这种变化是否反映了自然过程或主要是由于方法的差异。为了阐明BC对碳埋葬的重要性，需要限制应用方法的特异性。在这里，使用推定的BC标准品、潜在干扰物质和天然基质标准品评估了常用化学热氧化（CTO）方法的操作范围和适用性。试验结果证实了该方法对海洋沉积物的适用性。完整性测试与模型基板表明适用于低碳土壤，但只有较低的特异性海水颗粒物。在一组采用CTO方法的研究中，海洋沉积物样品的BC含量被证明与相关的地球化学信息一致。BC分离物在环境基质标准中的放射性碳含量显示出与热解多环芳烃（PAH）的放射性碳特征相似，在此用作燃烧的分子标记（BC的现代分数f（M）为0.065 +/- 0.014，PAHS为0.056 +/- 0.020），同时明显不同于本体TOC的放射性碳含量（f（M）= 0.61 +/-0.08）。一些紧迫的问题，如土壤和沉积物中黑碳的全球积累速率，可能会被证明是接近的化学氧化技术的BC量化。
Formation of highly condensed black carbon (BC) from vegetation fires and wood fuel combustion presumably transfers otherwise rapidly cycling carbon from the atmosphere-biosphere cycle into a much slower cycling geological form. Recently reported BC fractions of total organic carbon (TOC) in surficial marine sediments span a wide range (2-90%), leaving it presently unclear whether this variation reflects natural processes or is largely due to method differences. In order to elucidate the importance of BC to carbon burial the specificity of applied methods needs to be constrained. Here the operating range and applicability of a commonly used chemothermal oxidation (CTO) method is evaluated using putative BC standards, potentially interfering substances, and natural matrix standards. Test results confirm the applicability of the method to marine sediments. Integrity tests with model substrates suggest applicability to low-carbon soils but only with a lower specificity to seawater particulate matter. The BC content of marine sediment samples in a set of studies employing the CTO method proved to be consistent with associated geochemical information. The radiocarbon content of the BC isolate in an environmental matrix standard was shown to be similar to the radiocarbon signature of pyrogenic polycyclic aromatic hydrocarbons (PAHs), here serving as molecular markers of combustion (fraction modern f(M) of BC was 0.065 +/- 0.014 and of PAHS 0.056 +/- 0.020), while being clearly distinct from the radiocarbon content of the bulk TOC (f(M) = 0.61 +/- 0.08). Urgent questions such as the global accumulation rate of black carbon in soils and sediments may prove approachable with the chemothermal oxidation technique of BC quantification.