珠江口表层沉积物有机质碳氮丰度及其同位素组成与来源分析

The carbon/nitrogen abundance of organic matter and their isotope compositions of surface sediments in the Pearl River estuary for source input analyses

  • 摘要: 珠江河口的海−陆相互作用及其机制复杂,识别海−陆相互作用与人类活动在沉积物中的记录,对海洋生态环境的保护以及人与自然协调共生的认识具有重要意义。本文通过测定珠江口伶仃洋表层沉积物中总有机碳(TOC)、总氮(TN)和稳定碳氮同位素组成(δ13Corgδ15Ntot)多种参数,结合三端元混合模型研究珠江口海域表层沉积有机质特征与来源输入。结果表明,伶仃洋沉积有机质的来源主要是陆源、海源与污水来源,具有多源性。表层沉积物中陆源、海源与污水来源有机质占比的平均值分别为48.1%、42.3%和9.7%;表明珠江河口区域表层沉积物有机质具有以陆源有机质输入为主的多端元混合特征,而人为活动产生的污水来源有机质占比较高,值得进行深入研究。

     

    Abstract: The land-sea interaction and its mechanism in the Pearl River estuary are complex. Identifying the land-sea interaction and the recording of human activities in sediments is of great significance for the protection of marine ecological environment and the understanding of coordinated coexistence between humans and nature. Total organic carbon (TOC), total nitrogen (TN) and stable carbon and nitrogen isotope (δ13Corg and δ15Ntot) combined with a three-endmember-mixing model were measured to analyze the characteristics and sources of organic matter in surface sediment samples of Lingdingyang bay, the Pearl River estuary. The results indicate that the main sources of organic matter in Lingdingyang bay sediments are terrestrial, marine and sewage sources, with multiple sources. The average percentage contributions for terrestrial, marine and sewage sources in surface sediments are 48.1%, 42.3% and 9.7%. It shows that the organic matter in the surface sediments of the Pearl River estuary has the characteristics of multi endmember mixing dominated by terrestrial organic matter input, while the organic matter from sewage generated by human activities accounts for a relatively high proportion, which is worth conducting further research.

     

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