极地研究

极地研究 ›› 2021, Vol. 33 ›› Issue (2): 198-208.DOI: 10. 13679/j.jdyj.20200042

• 研究论文 • 上一篇    下一篇

西南极湖泊沉积类脂记录的有机质来源及生态环境变化

郭晓泽，赵军，韩正兵，李栋，张海峰，孙维萍，扈传昱，潘建明   

  1. 自然资源部海洋生态系统动力学重点实验室, 自然资源部第二海洋研究所, 浙江 杭州 310012
  • 收稿日期:2020-05-08 修回日期:2020-06-08 出版日期:2021-06-30 发布日期:2021-05-31
  • 通讯作者: 赵军
  • 基金资助:
    国家自然科学基金 (41976228、41976227)，中央级公益性科研院所基本科研业务费专项资金(JG1805)，自然资源部国家海洋局极地考察办公室项目(IRASCC2020-2022-No.01-01-02、02-02)

Historical changes in organic matter sources and ecological environment indicated by sedimentary lipid biomarkers in a West Antarctic lake

Guo Xiaoze, Zhao Jun, Han Zhengbing, Li Dong, Zhang Haifeng, Sun Weiping, Hu Chuanyu, Pan Jianming   

  1. Key Laboratory of Marine Ecosystem Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China
  • Received:2020-05-08 Revised:2020-06-08 Online:2021-06-30 Published:2021-05-31
  • Contact: Zhao Jun

PDF (PC)

860

摘要： 对西南极乔治王岛西湖沉积物XH1柱样进行了210Pb测年, 建立起百余年(1885~2006年)沉积地层序列。定量分析了该柱样中的正构烷烃、脂肪酸和甾醇等类脂生物标志物, 综合研究了其分子组合特征和大尺度气候事件[厄尔尼诺-南方涛动(ENSO)和南半球环状模(SAM)]指标, 探讨了湖泊沉积有机质来源、沉积环境和早期成岩作用及其与生态环境变化的关系。结果表明, 正构烷烃的主峰碳(nC23)、脂肪酸的后主峰碳(C24:0)、较高的C29甾醇含量和较低的SC21–/SC22+比值均显示, 苔藓、地衣等低等陆生植物是西湖沉积物中有机质的主要来源, 而水生动植物及微生物的贡献相对较少。脂肪酸C18:2/C18:0比值表明, 在年代际时间尺度上, 与ENSO相比, SAM对南极半岛生态系统可能更具影响力, 且对湖泊水生动植物的影响比陆生植物更为明显。内源输入的甾醇指标ACI显示, 西风变弱、南极半岛变暖时, 沉积物中水生生物贡献的有机质减少。整体而言, 过去的100多年中, 西湖呈弱氧化的沉积环境, 早期成岩作用较弱, 且气候事件对湖泊沉积环境影响不大。

关键词: 西南极, 湖泊, 沉积物, 类脂生物标志物, 有机质, 环境

Abstract: Based on 210Pb dating of XH1 core sediment samples from Xihu Lake on King George Island, Antarctica, a centennial (1885-2006) sedimentary stratigraphic sequence was established. The lipid biomarkers, such as n-alkanes, fatty acids and sterols, were quantitatively analysed. The characteristics of their molecular assemblages and large-scale climate events (El Ni?o-Southern Oscillation (ENSO) and Southern Hemisphere Annular Mode (SAM)) were synthetically studied. The source of organic matter, sedimentary environment, early diagenesis and their relationship with the changes in ecological environment were discussed. The results showed that the main peak carbon (nC23) of n-alkanes, the latter main peak carbon (C24:0) of fatty acids, the higher content of C29 sterols and the lower ratio of C21–/C22+ indicated that the main source of organic matter in sediment of Xihu Lake was lower terrestrial plants such as mosses and lichens, while the contribution of aquatic plants and microorganisms was relatively minor. The ratio of C18:2/C18:0 of fatty acids indicated that, on the interdecadal time scale, SAM rather than ENSO, may have significant influence on the ecosystems of Antarctic Peninsula, and the impact of SAM on aquatic organisms in lakes is more obvious than that on terrestrial plants. ACI, an autochthonous contribution index of sterols, showed that when the westerly wind weakened and the Antarctic Peninsula warmed, the organic matter contributed by aquatic organisms decreased. Overall, in the past 100 years, the Xihu Lake was in a weakly oxidized sedimentary condition, with weak early diagenesis, and the impact of large-scale climate events on the lake sedimentary environment was weak.

Key words: West Antarctic, lake, sediment, lipid biomarkers, organic matter, environment