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| 长江口及其邻近海域表层沉积物粒径及生源要素分布特征 |
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樊 鑫1,2,3, 程芳晋4, 俞志明1,2,3, 宋秀贤1,2,3
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1.中国科学院 海洋研究所 海洋生态与环境科学重点实验室;2.中国科学院大学;3.青岛海洋科学与技术国家实验室 海洋生态与环境科学功能实验室;4.青岛市环境监测中心站
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| 摘要: |
| 针对2015年长江口及其邻近海域所采集的43个表层沉积物样品, 通过粒径分析以及生物硅(BSi)、总有机碳(TOC)和总氮(TN)等生源要素参数的测定, 系统探讨了长江口表层沉积物粒径及生源要素的时空分布特征以及各要素的相互关系。结果表明: (1)长江口及其邻近海域表层沉积物组成以黏土质粉砂、粉砂质砂和砂为主。研究区域内, 粒径组成呈现明显的 “南细、北粗, 近岸细、离岸粗” 的分布特征, 长江口及浙江近岸泥质区的表层沉积物粒度最细, 中值粒径(Φ)在5以上; (2)调查海域表层沉积物中BSi含量在0.22%～1.82%之间, 沉积物中粉砂、黏土含量及平均粒径(Φ)均与BSi 含量呈显著正相关(P<0.01), 黏土矿物和粉砂较多的细颗粒沉积物更易累计和保存BSi; (3)TOC和TN的含量分别在0.04%～1.17%和0.01%～0.26%之间, 其分布特征与沉积物中值粒径(Φ)和BSi的分布也有明显的正相关性, 说明细颗粒沉积物更有利于有机质保存, 表层沉积物中的硅藻可能是有机物的来源之一。 |
| 关键词: 长江口 沉积物 粒度 BSi 有机质 |
| DOI：10.11759/hykx20170109001 |
| 分类号: |
| 基金项目:长江口及其邻近海域沉积硅藻记录与定量富营养化历史重建(41506142); 联合基金项目“海洋生态与环境科学”资助项目(U1406403); 国家自然科学基金资助项目(41276115) |
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| Research on surface sediment grain size and biogenic elements distribution in Yangtze Estuary and adjacent waters |
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FAN Xin,CHENG Fang-jing,YU Zhi-ming,SONG Xiu-xian
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| Abstract: |
| In 2015, we collected surface sediment samples from 43 stations in the Yangtze Estuary and its adjacent waters. We then analyzed the grain size and biogenic elements of the surface sediments, including biological silicon (BSi), total organic carbon (TOC), and total nitrogen (TN). In this paper, we discuss the spatial distributions and mutual relationships of the above features. The results show that the surface sediment in the Yangtze Estuary and adjacent waters is mainly composed of clayey silt, silty sand, and sand. In the investigated area, the grain size of the surface sediment appeared to have obvious distributions: fine in south and near shore area and coarse in the north and offshore area. We found the finest surface sediment in the Yangtze Estuary and Zhejiang coastal mud area, which had a median diameter (Φ) greater than 5. In addition, the BSi content of the surface sediments in the investigated waters ranged from 0.22%–1.82%, and was positively correlated with the surface sediment clay, silt content, and average particle size (P<0.01). Clay minerals and fine silt sediment readily accumulate and retain BSi. The contents of TOC and TN ranged from 0.04%–1.17% and 0.01%–0.26%, respectively, and their distributions showed a significant positive correlation with the median diameter (Φ) and BSi content, which suggests fine-grained sediments are more favorable for the preservation of organic matter, and that in these surface sediment samples diatoms are likely to be a source of organic matter. |
| Key words: Yangtze Estuary sediment grain size biological silicon organic matter. |