| 引用本文: | 王君兰,邓伟,张平宇,张家武.湖泊沉积物不同粒级组分有机碳同位素差异及其对实验结果的影响.湖泊科学,2014,26(4):625-631. DOI:10.18307/2014.0418 |
| WANG Junlan,DENG Wei,ZHANG Pingyu,ZHANG Jiawu.The differences in organic carbon isotope of different size components in lake sediments and its impact on experimental results. J. Lake Sci.2014,26(4):625-631. DOI:10.18307/2014.0418 |
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| 摘要: |
| 湖泊沉积物有机质碳同位素因常被用于识别沉积物中有机质来源或流域植被信息而逐渐成为一个常规代用指标,但当沉积物中有机质含量变化显著、赋存状态不同时,采用统一分析方法(全样或某一粒级组分)测试的结果在不同含量或赋存状态时是否会产生偏差,目前没有详细的研究进行评价.利用嘎顺诺尔湖泊沉积物,采用全样品、细颗粒组分(过120目筛和360目筛),分别进行有机质含量和同位素分析,评价选择不同粒级样品因有机质赋存状态不同对有机碳同位素分析结果的影响.结果显示,不同组分的烧失量或元素分析仪方法测得的有机质含量变化趋势相同,但不同组分的有机碳同位素结果出现差异:全样的有机碳同位素值存在较大波动,随着过筛孔径变小,δ13Corg值波动减小,且过360目筛的细颗粒组分的碳同位素值较全样或过120目筛后组分的δ13Corg值偏负.这一差异与有机质组分赋存的颗粒范围有关.对比认为过360目筛的细颗粒组分更有利于充分反应,且可获得较为准确的同位素值.因此,在进行不同湖泊沉积物δ13Corg值对比时,应注意研究使用样品的前处理方式,相同处理方式下的结果更具有可比性.该研究结果对于湖泊沉积物有机质碳同位素分析具有参考意义. |
| 关键词: 湖泊沉积物 全样品 细颗粒组分 有机碳同位素 |
| DOI：10.18307/2014.0418 |
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| 基金项目:国家重点基础研究发展计划"973"项目(2009CB421306);国家自然科学基金项目(40871093,41021091)联合资助 |
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| The differences in organic carbon isotope of different size components in lake sediments and its impact on experimental results |
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WANG Junlan1, DENG Wei2, ZHANG Pingyu3, ZHANG Jiawu3
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1.Lanzhou Library of Chinese Academy of Sciences, Lanzhou 730000, P. R. China;2.Gansu Institute of Geological Survey, Lanzhou 730000, P. R. China;3.MOE Key Laboratory of Western China's Environmental Systems/Research School of Arid Environment and Climate Change, Lanzhou University, Lanzhou 730000, P. R. China
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| Abstract: |
| The organic carbon isotope (OCI) of lake sediment has often been used to identify the source of organic matter in sediments or watershed vegetation, and gradually becomes a routine proxy indicator. However, when organic matter content changes significantly and in different forms, the OCI results from the unified approach (bulk sample or a graded composition) will produce deviation, no studies have evaluated this problem so far. This research chose sediment samples from rump lake in arid areas, analyzed the organic content and isotope using bulk sample and fine-grained components (screened through mesh size of 120 and 360), respectively. The influence on OCI results based on different sediment grain sizes and with different organic matter forms was evaluated. Results reveal different OCI values in those sediment even with similar organic matter from different sediment components. Obviously, this relates to the forms of organic matter. It shows that fine-grained components (screened through mesh size of 360) is more advantageous to full reaction, and obtain a more stable value. When comparing the δ13Corg value in different lake sediments, researchers should adapt same methods for sample pretreatment. The result has an important implication for the research on organic carbon isotope in lake sediments. |
| Key words: Lake sediments bulk sample fine-grained components δ13Corg |
