The use of lipid biomarkers as paleoenvironmental proxies relies on an accurate assessment of their organic matter (OM) sources. In this study, we analyzed multiple lipids in core sediments recovered from the Zhejiang–Fujian coastal mud area to provide a 160-year record of OM input to the East China Sea (ECS) coastal sediments and to reconstruct paleoenvironmental conditions over this interval. The molecular composition of the samples was characterized by a mixture of natural lipids, particularly those derived from terrestrial vascular plants, marine/riverine plankton and macrophytes, and bacteria. The sources of some lipid components were ambiguous/mixed as they were potentially derived from multiple precursor organisms and because of limitations associated with modern survey techniques. There is evidence that early diagenesis caused the preferential degradation of labile aquatic lipids and that the degradation of terrestrial lipids was more severe when subjected to complex horizontal–vertical transportation processes associated with deposition, resuspension, and redeposition. These processes may have led to an enhanced terrestrial OM signal in the normal (n)-alkane and n-alkanol records, which is at odds with, for example, those of the n-fatty acids, hopanoids, steranes, and sterols, which suggest a dominant marine OM source. Furthermore, we conclude that the occurrence of multiple sources, selective diagenesis, and test error has led to the distortion of redox and maturity indicators based on evidence from pristane-to-phytane (Pr/Ph) ratios and sterane/hopane indices in century scale. Overall, the phytol record suggests an increase in productivity after the early 20th century. Correspondingly, the diatom lipid biomarker records (based on C25 highly branched isoprenoid alkenes and C18:1ω9 fatty acids) reveal a fluctuating but overall increasing diatom productivity after the early 20th century, which coincides with a decreased proportion of the contribution from diatoms relative to that of total phytoplankton. This is believed to correspond to natural environmental changes, as well as anthropogenic impact.

中文翻译：

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多种脂质生物标志物记录过去160年来东海沿岸有机质来源和古环境变化

使用脂质生物标志物作为古环境代理依赖于对其有机物质 (OM) 来源的准确评估。在这项研究中，我们分析了从浙江-福建沿海泥区回收的岩心沉积物中的多种脂质，以提供 160 年东海 (ECS) 沿海沉积物 OM 输入的记录，并重建该区间的古环境条件。样品的分子组成以天然脂质混合物为特征，特别是来自陆生维管植物、海洋/河流浮游生物和大型植物以及细菌的脂质。一些脂质成分的来源不明确/混合，因为它们可能来自多种前体生物，并且由于与现代调查技术相关的限制。有证据表明，早期成岩作用导致不稳定的水生脂质优先降解，而陆地脂质在经历与沉积、再悬浮和再沉积相关的复杂水平-垂直运输过程时，降解更为严重。这些过程可能导致正常 (n)-烷烃和正烷醇记录中的陆地 OM 信号增强，这与例如正脂肪酸、hopanoids、甾烷和甾醇的那些不一致。表明主要的海洋 OM 来源。此外，我们得出结论，基于世纪尺度的原始烷与植烷 (Pr/Ph) 比率和甾烷 / 藿烷指数的证据，多源、选择性成岩作用和测试错误的发生导致氧化还原和成熟度指标的失真. 全面的，植醇记录表明，20 世纪初之后生产力有所提高。相应地，硅藻脂质生物标志物记录（基于 C25 高度支化的类异戊二烯烯烃和 C18:1ω9 脂肪酸）揭示了 20 世纪初期后硅藻生产力的波动但总体上增加，这与硅藻贡献的比例下降相吻合。总浮游植物。这被认为与自然环境变化以及人为影响相对应。这与硅藻贡献相对于总浮游植物贡献的比例下降相吻合。这被认为与自然环境变化以及人为影响相对应。这与硅藻贡献相对于总浮游植物贡献的比例下降相吻合。这被认为与自然环境变化以及人为影响相对应。