有机分子组成揭示渤海西岸末次盛冰期以来海平面变化对滨海湿地生态演化的影响  

Organic matter molecular composition reveals the impact of sea level change on the evolution of coastal wetland ecosystem since the Last Glacial Maximum on the west coast of Bohai Sea

作　　者：王鑫宇 徐海[1,2] 王晶 杨妍[1] 王福 刘丛强[1] WANG Xinyu;XU Hai;WANG Jing;YANG Yan;WANG Fu;Liu Cong-Qiang(School of Earth System Science,Tianjin University,Tianjin 300072,China;MOE Key Laboratory of Karst Georesources and Environment,Guizhou University,Guiyang 550025,China;Tianjin Geological Survey Centre,China Geological Survey,Tianjin 300170,China)

机构地区：[1]天津大学地球系统科学学院,天津300072 [2]贵州大学喀斯特地质资源与环境教育部重点实验室,贵州贵阳550025 [3]中国地质调查局天津地质调查中心,天津300170

出　　处：《地学前缘》2025年第3期320-333,共14页Earth Science Frontiers

基　　金：国家自然科学基金项目(42293262)。

摘　　要：滨海湿地生态系统是重要的生态系统之一,对环境变化响应敏感。海平面变化会直接影响滨海湿地的物质来源,进而影响湿地生态系统演化。然而,由于可靠地质记录的相对稀缺,长时间尺度海平面变化对滨海湿地生态系统的影响尚未全面澄清。本文旨在从沉积物有机分子组成视角探讨末次盛冰期(约22000 a BP)以来渤海西岸海平面变化对滨海湿地生态系统演化的影响。本文基于超高分辨率傅里叶变换离子回旋共振质谱(FT-ICR MS)技术分析了渤海西岸沉积物有机分子组成,结果表明末次盛冰期沉积物内源脂肪族化合物占比较高,在海平面较现代海平面平均低约130 m,在渤海西岸滨海湿地不发育情境下该区可能存在局部水系并发育湖沼环境。进入全新世,海平面快速上升,本文岩心的两个海相地层记录了约7100~6900 a BP和约6000~5650 a BP两次海侵事件;约5650 a BP以后,海平面相对稳定但缓慢下降,海岸线逐渐后退,形成了6道古海岸线和6期潟湖洼地。本研究表明滨海沉积物有机质CHO组分对海平面变化引起的环境变迁响应灵敏,有机质H/C和O/C的变化趋势指示滨海湿地在约8050~4850 a BP经历了陆相—海相—陆相的环境转变。其中约8050 a BP和约4850 a BP较高的O/C和较低的H/C表明这两个时期渤海西岸可能发育潟湖洼地,有机质主要来自陆生、半水生植物及土壤微生物活动;约5700 a BP内源脂肪族化合物占比明显较高,表明滨海湿地转变为海洋环境,有机质主要来源转变为水生藻类和浮游生物。约1350 a BP内源有机组分占比15.68%,显著高于约8050 a BP和约4850 a BP,表明湿地生态演化可能受到较强人类活动的干扰。本文的研究结果为认识海平面变化对滨海湿地生态系统演化的影响提供了新的视角和证据。The coastal wetland ecosystem is one of the important ecosystems and is sensitive to environmental changes.Changes in sea level directly affect the material sources of coastal wetlands,thereby influencing the development of wetland ecosystems.However,the impact of long-term sea level change on coastal wetland ecosystems has not been fully understood due to the lack of reliable geological records.This article aims to explore the impact of Bohai sea level changes on the development of coastal wetland ecosystems since the Last Glacial Maximum(LGM;~22000 a BP)based on sedimentary organic matter(SOM)molecular composition.This article analyzed the SOM molecular composition on the west coast of the Bohai Sea with ultra-high-resolution Fourier transform ion cyclotron resonance mass spectrometry technology.The results show that the proportion of endogenous aliphatic compounds in the sediments was relatively high during the LGM.The sea level was averagely~130 m lower than the modern and no wetlands around the modern coast of the Bohai Sea were developed during this period,suggesting that the region may have developed local water systems and lacustrine environments.The sea level rose rapidly since the Holocene.Two marine facies in the core of this article recorded two marine transgression events during~7100-6900 a BP and~6000-5650 a BP.The sea level was relatively constant since~5650 a BP and gradually retreated thereafter,resulting in 6 ancient coastlines and 6 stages of lagoon and depressions.The results suggest that the SOM CHO-component is sensitive to environmental changes induced by sea level change.Variations in H/C and O/C ratios indicate that the coastal wetlands underwent terrestrial-marine-terrestrial transformations from~8050 to 4850 a BP.The higher O/C and lower H/C ratios during~8050 a BP and~4850 a BP indicate that wetlands and lagoon depressions might have developed on the west coast of the Bohai Sea,and changes in the SOM can be mainly ascribed to changes in terrestrial,semi-aquatic vegetation and soil micr

关 键 词：滨海湿地 海平面变化 有机分子组成 傅里叶变换离子回旋共振质谱 生态演化 

分 类 号：X142[环境科学与工程—环境科学] X171.1