| 摘要: |
| 对环雷州半岛近海43个海底表层沉积物的总有机碳（TOC）、总氮（TN）、沉积介质条件（包括沉积物粒度）进行了分析，探讨了沉积物TOC、TN的区域分布特征以及影响有机碳分布的主要因素。结果表明，环雷州半岛近海海域海底表层沉积物有机碳含量在0~0.79%之间，平均值为0.26%。与中国其它近海海域相比，环雷州半岛大部分近海区域海底表层沉积物有机碳含量明显偏低，为有机质贫乏区，仅雷州半岛西南部流沙湾近海海域为TOC相对高值区。总氮含量也不高，在0.011%到0.100%之间，TOC与TN存在较强的正相关性，且平面上TOC与TN分布高度重合，显示氮元素主要以有机化合物形式存在。TOC/TN比值在5.1~14.3之间，表明沉积有机质具有陆源输入和海洋自生来源的混合特征，但以雷州半岛西侧北部及东侧中部海域受陆源有机质输入影响更大。大多数站位海底沉积物粒度构成以粉砂为主、粘土次之，少数站位以砂质沉积为主。沉积物有机碳含量与粘土及粉砂含量呈弱正相关性，与沉积物pH值、Eh值及砂含量呈弱负相关性，这表明海底沉积物有机质丰度受有机质来源输入、海底氧化还原状态和沉积水动力条件（沉积物粒度）等因素综合控制。 |
| 关键词: 海底表层沉积物 总有机碳含量 总氮 环境因素 环雷州半岛海域 |
| DOI：10.11759/hykx20191012002 |
| 分类号:P736.41 |
| 基金项目:广东海洋大学博士科研启动项目（R17001）；南方海洋科学与工程广东省实验室（湛江）项目（ZJW-2019-08） |
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| Distribution and controlling factors of organic carbon in surface sediments of the coastal region surrounding Leizhou Peninsula |
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HAN Yong-qiang1, XIA Jia1,2, TAN Jing-qian1, ABARIKE Grace Awinmalsim1, SONG Zhi-guang1
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1.College of Chemistry and Environment, Guangdong Ocean University, Zhanjiang 524088, China;2.Southern Marine Science and Engineering Guangdong Laboratory(Zhanjiang), Zhanjiang 524013, China
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| Abstract: |
| The total organic carbon (TOC) and total nitrogen (TN), sedimentary redox state and granularity composition of 43 seafloor surface sediments in the coastal region of Leizhou Peninsula were analyzed, and the distribution of TOC, TN and its possible controlling factors were discussed. The results show that the organic carbon content in the surface sediments of the coastal region surrounding Leizhou Peninsula is between 0 and 0.79%, with an average of 0.26%. Compared with other offshore sea area in China, the organic carbon content of seafloor surface sediments in most offshore areas of surrounding Leizhou Peninsula is significantly lower, which is an area with poor organic matter. Only the offshore sea area of Liusha Bay in the southwest of Leizhou Peninsula is an area with relatively high TOC value. The total nitrogen content is also not high, between 0.011% and 0.100%. There is a strong positive correlation between TOC and TN, and the spatial distribution of TOC and TN highly coincide, indicating that nitrogen mainly exists in the form of organic compounds. The ratio of TOC/TN is between 5.1 and 14.3, indicating that the sedimentary organic matter has the mixed characteristics of terrestrial and marine authigenic sources. However, the northern part of the western Leizhou Peninsula and the central part of the eastern Leizhou Peninsula are more affected by the input of terrestrial organic matter. Most of the stations arecomposed of silt and clay, anda few are composed of sand. The organic carbon content of sediments has a weak positive correlation with the content of clay and silt, and a weak negative correlation with the pH value, Eh value and sand content of sediments, which indicates that the TOC abundance of surface sediments is comprehensively controlled by the input of organic matter sources, the seafloor of redox state and the sedimentary hydrodynamic conditions (sediment grain size). |
| Key words: seafloor surface sediments total organic carbon content total nitrogen environmental factor offshore of surrounding Leizhou Peninsula |
