测定了珠江口及近海表层沉积物中总有机碳(TOC), 总氮(TN)及稳定碳同位素组成和几类主要有机化合物(水解氨基酸THAA、糖类TCHO、脂类lipid、酸不溶有机物AIOC), 并分析了沉积有机质及化合物的特征和来源。结果表明珠江口表层沉积有机质主要为陆源和水生混合来源, 而近海有机质主要为当地水生来源。大量的陆源高等植物(含有较多的木质素、纤维素等)输入珠江口, 使得珠江口个别站位沉积物中糖类物质含量大幅高于近海样品; 而珠江口与近海沉积物中水生来源有机质的含量相当。氨基酸和糖类占TOC的份额在浮游生物和悬浮颗粒物中分别为56%和48%, 在表层沉积物中为19%, 说明珠江口和近海的有机质从水柱到达沉积物-水界面的过程中经历了较充分的降解。珠江口样品中活性组分氨基酸和糖类占TOC的份额低于近海, 可能说明珠江口沉积有机质的降解程度高于近海。

The authors study the characteristics and sources of organic carbon, nitrogen and the hydrolysable amino acids (THAA), total carbohydrates (TCHO), total lipid and acid-insoluble organic compounds (AIOC) in the surface sediments of the Pearl River Estuary (PRE) and its adjacent shelves. The results show that the organic matter in the PRE was mainly derived from mixed sources of terrestrial and aquatic origins, whereas the organic matter in the adjacent shelves was predominantly algal-derived. Terrestrial higher plants were rich in more lignin and cellulose, which were exported to the PRE. As a result, the content of TCHO in the sediment of the estuary was higher than that in the adjacent shelves, while the content of aquatic organic matter in the estuary was close to that in the adjacent shelves. The proportions of THAA and TCHO were 56%, 48% and 19% in plankton, suspended particulate and surface sediment, respectively; suggesting that the organic matter had undergone degradation during the sedimentation to the water-sediment interface.

中国科学院知识创新工程重要方向性项目(珠江河口及近海生态环境演化规律与调控机制研究, KCX2-SW-212)

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