渤海-北黄海表层沉积物中正构烷烃的组合特征及其指示意义的探讨  

Study on the Indication of n-alkanes in Surface Sediments from the Bohai Sea and the North Yellow Sea

作　　者：操云云 邢磊[1,2] 王星辰[1] 赵美训[1,2] 

机构地区：[1]中国海洋大学海洋化学理论与工程技术教育部重点实验室,山东青岛266100 [2]中国海洋大学海洋有机地球化学研究所,山东青岛266100

出　　处：《中国海洋大学学报（自然科学版）》2018年第3期104-113,共10页Periodical of Ocean University of China

基　　金：国家重点研发计划项目(2016YFA0600904);国家自然科学基金项目(41276068)资助~~

摘　　要：正构烷烃的组合特征是古环境研究的有力工具,但在渤海-北黄海低碳数正构烷烃的来源及其指示意义的研究还较缺乏。本文主要对渤海-北黄海60个站位表层沉积物中的正构烷烃(C14~C38)的组成、分布、各指标间的相关性及其来源进行了研究。研究结果表明:(1)渤海-北黄海的正构烷烃组成呈单峰模式,C27、C29、C31正构烷烃含量较高,且具有明显奇碳优势。(2)各个站位中高碳数正构烷烃碳优势指数(CPIH)空间分布表明该研究海域陆源输入主要沉积在河口;烷烃指数(AI)表示该海域整体上陆源输入的草本植物与木本植物所占比例相似;低碳数正构烷烃碳优势指数(CPIL)的平均值为0.9,不具有奇偶碳优势,可能受到石油及其衍生物的影响。(3)主成分分析(PCA)发现渤海-北黄海表层沉积物中高低碳数正构烷烃分布不仅受水动力影响,来源也是其分布的重要影响因素。(4)将高碳数正构烷烃相对含量((C27+C29+C31)/TOC)和低碳数正构烷烃相对含量((C15+C17+C19)/TOC)分别与三种浮游植物生物标志物相对含量((B+D+A)/TOC)做相关性分析,进一步表明该研究海域高碳数正构烷烃来自陆源输入,C15、C17、C19正构烷烃不能作为海源生物标志物。此外,降解指数(C26正构醇/C29正构烷烃)与C15+C17+C19正构烷烃含量的对比表明降解不是该研究海域低碳数正构烷烃分布的主要控制因素。低碳数正构烷烃的来源和分布控制机制还有待进一步研究。The composition of n alkanes is a powerful tool to study paleo environment, but the research on the sources and indication of the low carbon number n alkanes is still lacking in the Bohai Sea （BS） and the North Yellow Sea （NYS）. Sedimentary n alkanes have been widely used to discuss the distribution mechanism and sources of sedimentary organic matter. In this study, the composition and spatial distribution of C14-C38 n alkanes in 60 surface sediments from the BS and the NYS were studied. It was found that n alkanes composition displayed a mono modal with the long chain C27, C29, C31n alkanes dominating and had a strong odd carbon preference in the BS and the NYS. The spatial distribution of carbon preference index of high carbon number n alkanes （CPIhigh） showed that the dominant terrigenous input mainly deposit in the estuary. Alkane Index indicated tha terrigenous input of herbaceous plants and woody plants were similar in the whole area. In contrast, the average value of carbon preference index of low carbon number n alkanes （CPIlow） was 0. 9 with no obvious odd even carbon preference, suggesting various sources of low carbon number n alkanes and the influences of petroleum and its derivatives contamination on n alkanes. Principal component analysis （PCA） indicated that spatial distributions of high carbon number n alkanes and low carbon number n alkanes were controlled by hydrological conditions and the sources of n alkanes. The correlation analysis between the TOC normalized content of C27＋C29＋C31 n alkanes （（C27＋C29＋C31）/TOC）, the TOC normalized content of C15＋C17＋C19 n alkanes （（C15＋C17＋C19）/TOC） and the TOC normalized content of three kinds phytoplankton biomarkers （B＋D＋A/TOC） indicated that C27＋C29＋C31n alkanes derived from terrigenous plant while C15, C17, C19 n alkanes were not good marine biomarkers. In addition, the comparison of the degradation index （C26 OH/C29） and C15＋C17＋C19n alkanes content showed that degradation was not t

关 键 词：渤海-北黄海 表层沉积物 正构烷烃 指示意义 

分 类 号：P734.43[天文地球—海洋化学]