赵美训, 高文献, 邢磊, 张玉琢, 李莉, 刘健. 老黄河口海区表层沉积物有机质来源的BIT指标估算[J]. 海洋地质与第四纪地质, 2011, 31(4): 29-37. DOI: 10.3724/SP.J.1140.2011.04029
引用本文: 赵美训, 高文献, 邢磊, 张玉琢, 李莉, 刘健. 老黄河口海区表层沉积物有机质来源的BIT指标估算[J]. 海洋地质与第四纪地质, 2011, 31(4): 29-37. DOI: 10.3724/SP.J.1140.2011.04029
ZHAO Meixun, GAO Wenxian, XING Lei, ZHANG Yuzhuo, LI Li, LIU Jian. ESTIMATES OF THE ORIGINS OF ORGANIC MATTER IN THE OLD-HUANGHE ESTUARY USING THE BIT ⅡNDEX[J]. Marine Geology & Quaternary Geology, 2011, 31(4): 29-37. DOI: 10.3724/SP.J.1140.2011.04029
Citation: ZHAO Meixun, GAO Wenxian, XING Lei, ZHANG Yuzhuo, LI Li, LIU Jian. ESTIMATES OF THE ORIGINS OF ORGANIC MATTER IN THE OLD-HUANGHE ESTUARY USING THE BIT ⅡNDEX[J]. Marine Geology & Quaternary Geology, 2011, 31(4): 29-37. DOI: 10.3724/SP.J.1140.2011.04029

老黄河口海区表层沉积物有机质来源的BIT指标估算

ESTIMATES OF THE ORIGINS OF ORGANIC MATTER IN THE OLD-HUANGHE ESTUARY USING THE BIT ⅡNDEX

  • 摘要: 识别边缘海沉积有机质的来源对碳循环的研究有重要意义。BIT (Branched and Isoprenoid Tetractter)指标作为一种新的指示陆源有机质输入的指标,近年来被广泛用于判断河口区及边缘海沉积有机质的来源。BIT指标对沉积有机质来源的指示,是基于土壤细菌生物标志物(Branched GDGTs)与水生古菌生物标志物(crenarchaeol)的比值,具有指示明确、受成岩作用影响小等优点。目前,BIT指标在我国边缘海还未有应用,我们选取了黄海西部海域老黄河口海区的31个表层样,分析了其中微生物标志物的含量及BIT指标,结果显示:老黄河口附近显示较高的BIT值(>0.15),离岸逐渐降低,Branched GDGTs的含量范围为5~94 ng/g,与BIT指标具有相似的分布趋势。BIT指标与另一指标ATB (陆源长链奇碳烷烃与海源浮游植物生物标志物的比值)的对比研究发现,二者有相同的空间分布模式,在老黄河口海区的值比较高,离岸海区值较低。但是ATB比BIT的绝对数值高,这可能与ATB指标包括了陆源植被及土壤的共同输入,而BIT指标仅代表与土壤有机质的贡献有关,也可能与不同化合物降解速率不同有关。

     

    Abstract: Distinguishing the sources of organic matters in marginal sea sediments is an important aspect of carbon cycle research. The BIT index, as a new proxy for terrestrial organic matter, has been recently used to quantitatively estimate sources of organic matters in estuary and marginal sea sediments. Based on the ratio of crenarchaeol (derived from aquatic crenarchaeota) to Branched GDGTs (produced by soil bacteria), the BIT index has the advantages that the biomarkers have specific origins and they are less affected by diagenesis. So far, the BIT index has not yet been applied to marginal seas of China. We report the contents of microbial biomarkers and the BIT index of 31 surface sediment samples from the western Yellow Sea near the Old-Huanghe River estuary. Our results show higher BIT values (>0.15) for samples close to the Old-Huanghe River, and lower BIT values seaward. The contents of Branched GDGTs range between 5 and 94 ng/g, showing a similar spatial trend with the BIT index. Another biomarker ratio index of terrestrial organic matter, the ATB index (ratio of terrestrial odd-numbered n-alkanes to marine phytoplankton biomarkers), also reveals a similar spatial pattern with higher values near the Old-Huanghe River estuary and decreasing values seaward. However, the absolute values of ATB index are much higher than the BIT values. The differences between ATB and BIT most likely reflect the fact that the ATB index contains both vegetation and soil organic matter input while the BIT index only represents soil organic matter, but they could be caused by different degradation rates of the compounds in the BIT and ATB index.

     

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