羟基四醚生物标志物指示长江口全新世环境演变的研究  

Research on the environmental indication of OH-GDGTs to the Holocene Yangtze Estuary

作　　者：袁梦 肖文杰 年小美 张卫国[3] 葛黄敏[1] 许云平 YUAN Meng;XIAO Wenjie;NIAN Xiaomei;ZHANG Weiguo;GE Huangmin;XU Yunping(College of Oceanography and Ecological Science,Shanghai Ocean University,Shanghai 201306,China;Department of Biology,HADAL&Nordcee,University of Southern Denmark,5230 Odense M,Denmark;East China Normal University State Key Laboratory of Estuarine and Coastal Research,Shanghai 200241,China)

机构地区：[1]上海海洋大学海洋科学与生态环境学院,上海201306 [2]Department of Biology,HADAL&Nordcee,University of Southern Denmark,5230 Odense M,Denmark [3]华东师范大学河口海岸学国家重点实验室,上海200241

出　　处：《海洋科学》2024年第7期22-32,共11页Marine Sciences

基　　金：上海市科委科技计划项目(23230760300);国家自然科学基金项目(42261144743)。

摘　　要：长江口作为中国最大的河口,其沉积物记录了东亚季风演化及海陆变迁的丰富信息,是研究环境演化的理想区域。脂类生物标志物具有特定的生物来源,对外部环境变化响应敏感且具有较高的保存潜力,是一类重要的古环境代用指标。本研究在长江口横沙岛采集了一根40m长的沉积柱样(HSD22),运用高效液相色谱质谱联用仪分析了微生物细胞膜脂的生物标志物——甘油二烷基甘油四醚(GlycerolDialkyl Glycerol Tetraethers;GDGTs),计算了BIT(Branched Isoprenoid Tetraether)、MI(Methane Index)、RI-OH(the ring index of OH-GDGTs)等分子指标,着重对羟基化GDGTs(OH-GDGTs)指标进行了研究。对比前人研究结果后发现OH-GDGTs具有环境特异性,不同环境中的生物来源不同,导致化合物的变化趋势不同。基于OH-GDGTs温度指标, HSD22的三次沉积相变换分别对应全新世的早期偏冷、中期偏暖、晚期偏冷的气候模式。此外,OH-GDGTs还显示出指示盐度变化和甲烷活动的潜力,OH/ALL%指标可以有效反映河口区域淡水信号的变化,但该指标在非河口区的适用性还有待进一步验证。The Yangtze River Estuary,the largest estuary in China,is an ideal area for studying environmental evo-lution because its sediments record abundant information of East Asian monsoon evolution and land–sea transition.Lipid biomarkers are an important class of paleoenvironmental proxies due to their specific biological origins,sen-sitive responses to external environmental changes,and high preservation potential.In this study,a 40-m-long sediment column(HSD22)was collected from the Yangtze River Estuary.High-performance liquid chromatogra-phy-mass spectrometry was used to analyze glycerol dialkyl glycerol tetraethers(GDGTs),a microbial membrane lipid biomarker.Molecular indexes such as branched isoprenoid tetraether index,methane index,and ring index of OH-GDGTs were calculated.This study found that the biological origin of OH-GDGTs varies across different en-vironments,resulting in distinct compositional trends.The three sedimentary facies transitions of core HSD22 cor-respond to the early,middle,and late Holocene periods,and the corresponding cold-warm-cold temperature trends are recorded based on the OH-GDGT temperature index.OH-GDGTs demonstrate potential in indicating salinity changes and methane activities.The OH/ALL%index can effectively reflect changes in freshwater signals in estu-ary areas;however,its applicability in non-estuary areas requires further verification.

关 键 词：长江口 GDGTs 盐度 甲烷 

分 类 号：P734.5[天文地球—海洋化学]