| 珠江口淇澳岛滨海湿地沉积环境演化及其对人类活动的响应 |
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| 引用本文： | 叶翔,李靖,王爱军.珠江口淇澳岛滨海湿地沉积环境演化及其对人类活动的响应[J].海洋学报,2018,40(7):79-89. |
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| 作者姓名： | 叶翔 李靖 王爱军 |
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| 作者单位： | 1.国家海洋局第三海洋研究所 海洋与海岸地质实验室, 福建 厦门 361005 |
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| 基金项目： | 国家海洋局第三海洋研究所基本科研业务费（海三科2015007，海三科2017015）；国家自然科学基金项目（41776099）；全球变化与海气相互作用专项（GASI-03-04-01-03） |
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| 摘 要： | 滨海湿地作为人类活动和全球变化反应最为敏感的区域，其沉积记录可以反映出周边地区环境变化及人类活动信息。珠江口淇澳岛滨海湿地钻孔分析结果表明，在中全新世期间淇澳岛附近海域为河口湾环境，在风化层以上开始出现淤积，但在4 200 a BP前后受极冷气候的影响，沉积物粗化；自2 500 a BP以来，沉积环境相对稳定，在小冰期期间略有变化。沉积速率计算结果显示:淇澳岛附近海域自中全新世高海面以来的平均沉积速率为0.29 cm/a，4 160~2 500 a BP、2 500 a BP-1488年、1488-1893年、1893-1986年、1990-2007年期间的平均沉积速率分别为:0.17 cm/a、0.23 cm/a、0.35 cm/a、1.37 cm/a和5.94 cm/a，沉积速率逐渐增大，反映了珠江三角洲演化过程中沉积相与沉积环境的变化；1986-1990年期间的海堤建造极大地扰动了该钻孔上部的沉积过程，在工程施工期间共沉积了厚度约112 cm的沉积层，而在海堤建成后，沉积速率也显著增大。沉积物总有机碳、总氮和C/N值的垂向分布表明，在4 160~2 500 a BP期间受海洋环境影响较大，沉积物中有机碳以海源为主，2 500 a BP以来沉积物中碳、氮含量明显增大，C/N也相应变大，有机碳主要来源于陆源输入，但在小冰期期间海源有机碳贡献略有所增大；近百年来由于受人类活动影响显著，陆源有机碳的贡献快速增加。
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| 关 键 词： | 珠江口 滨海湿地 沉积环境 沉积速率 人类活动 |
| 收稿时间： | 2017/8/10 0:00:00 |
| 修稿时间： | 2017/12/10 0:00:00 |
Sedimentary environment and its response to anthropogenic impacts in the coastal wetland of the Qi'ao Island, Zhujiang River Estuary |
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| Ye Xiang,Li Jing and Wang Aijun.Sedimentary environment and its response to anthropogenic impacts in the coastal wetland of the Qi''ao Island, Zhujiang River Estuary[J].Acta Oceanologica Sinica (in Chinese),2018,40(7):79-89. |
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| Authors: | Ye Xiang Li Jing and Wang Aijun |
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| Institution: | 1.Laboratory for Coast and Ocean Geology, Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, China2.School of Geography and Tourism, Guangdong University of Finance & Economics, Guangzhou 510320, China |
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| Abstract: | Coastal wetland is an interaction interface among terrestrial, ocean and atmosphere, and is sensitive to the responses of global change and anthropogenic impacts, and the sedimentary records in coastal wetland can be used to reveal the information of local environmental change and anthropogenic impacts. Analyzed results for the sediment core named QA, obtained by drilling in coastal wetland of west Qi''ao Island (QAI), indicate that the surrounding area of the QAI was estuarine environment during the mid-Holocene, and the sea-bed began to experience a slight accumulation. However, due to the extreme cold climate influence near 4 200 a BP, the sediment showed a coarsen trend. Since 2 500 a BP, the sedimentary environment near the QAI was stable except during the Little Ice Age (LIA). Based on the radioisotope dating (14C and 210Pb) and the inferring conclusions according to the sedimentary structure of the core and sediment grain size variation, the mean sedimentation rate since mid-Holocene was 0.29 cm/a, and the sedimentation rates in the stages of 4 160-2 500 a BP, 2 500 a BP-1488 AD, 1488-1893 AD, 1893-1986 AD, and since 1990 AD were 0.17 cm/a, 0.23 cm/a, 0.35 cm/a, 1.37 cm/a and 5.94 cm/a, respectively. The increase of sedimentation rate indicated the variation of sedimentary facies and sedimentaryenvironment during the formation and evolution of the Zhujiang River Delta. During 1986-1990, the construction of the seawall disturbed the sedimentary process immensely and induced a 112 cm sediment layer occurred near the seawall, and the sedimentation rate increased evidently after the construction of seawall. The depth-distribution of total organic carbon (TOC), total nitrogen (TN) and C/N ratio indicated that the organic carbon was composed mainly by marine source during 4 160-2 500 a BP because the sedimentary environment near the QAI was influenced by marine environment mainly; since 2 500 a BP, the contents of TOC and TN increased as well as the variation of the C/N ratio revealed that the organic carbon mainly came from terrestrial input, although the contribution of marine source increased slightly during the LIA; however, the contribution of terrestrial organic carbon increased remarkably in recent one hundred years due to the intense anthropogenic impacts in the catchment area of the Zhujiang River and surrounding area of the estuary. |
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| Keywords: | Zhujiang River Estuary coastal wetland sedimentary environment sedimentation rate anthropogenic impact |
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