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| 羟基四醚生物标志物指示长江口全新世环境演变的研究 |
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袁梦1, 肖文杰1,2, 年小美3, 张卫国3, 葛黄敏1, 许云平1
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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
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| 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40 m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(Glycerol Dialkyl 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。 |
| 关键词: 长江口 GDGTs 盐度 甲烷 |
| DOI：10.11759/hykx20240119002 |
| 分类号:P734.5 |
| 基金项目:上海市科委科技计划项目(23230760300);国家自然科学基金项目(42261144743) |
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| Research on the environmental indication of OH-GDGTs to the Holocene Yangtze Estuary |
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YUAN Meng1, XIAO Wenjie1,2, NIAN Xiaomei3, ZHANG Weiguo3, GE Huangmin1, XU Yunping1
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1.College of Oceanography and Ecological Science, Shanghai Ocean University, Shanghai 201306, China;2.Department of Biology, HADAL &Nordcee, University of Southern Denmark, 5230 Odense M, Denmark;3.East China Normal University State Key Laboratory of Estuarine and Coastal Research, Shanghai 200241, China
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| Abstract: |
| The Yangtze River Estuary, the largest estuary in China, is an ideal area for studying environmental evolution 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, sensitive 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 chromatography-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 environments, resulting in distinct compositional trends. The three sedimentary facies transitions of core HSD22 correspond 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 estuary areas; however, its applicability in non-estuary areas requires further verification. |
| Key words: Yangtze River Estuary GDGTs salinity methane |