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热带海洋学报

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钦州湾水体中溶解有机质的组分特征及其来源分析

姜世豪1, 廖日权1, 2, 3*, 牛东蕾4, 乔真4, 鲁栋梁1, 2, 3, 唐建辉1, 2, 4
  

  1. 1. 北部湾大学海洋学院, 广西 钦州 535011

    2. 平陆运河河口海湾生态系统广西野外科学观测研究站, 北部湾大学海洋学院, 广西 钦州 535011

    3. 广西海洋环境灾害过程与生态保护技术重点实验室, 北部湾大学海洋学院, 广西 钦州 535011

    4. 中国科学院烟台海岸带研究所, 山东 烟台 264003



  • 收稿日期:2025-10-27 修回日期:2026-01-05 接受日期:2026-01-13
  • 通讯作者: 廖日权
  • 基金资助:
    国家自然科学基金(42476043)、钦州市科研与技术开发项目(202116623)以及中国大学生创新创业训练计划项目(S202411607021)

Distribution characteristics, compositions and sources of dissolved organic matter in Qinzhou Bay

JIANG Shihao1, LIAO Riquan1, 2, 3*, NIU Donglei4, QIAO Zhen4, LU Dongliang1, 2, 3, TANG Jianhui1, 2, 4   

  1. 1. College of Marine Sciences, Beibu Gulf University, Qinzhou 535011, China;

    2. Pinglu Canal and Beibu Gulf Coastal Ecosystem Observation and Research Station of Guangxi, College of Marine Sciences, Beibu Gulf University, Qinzhou 535011, China;

    3. Guangxi Key Laboratory of Marine Environmental Disaster Processes and Ecological Protection Technology, College of Marine Sciences, Beibu Gulf University, Qinzhou 535011, China;

    4. Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China



  • Received:2025-10-27 Revised:2026-01-05 Accepted:2026-01-13
  • Supported by:
    The National Natural Science Foundation of China(42476043); the Scientific Research and Technology Development project of Qinzhou(202116623); China College Students' Innovation and Entrepreneurship Training Program Project(S202411607021)

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摘要： 溶解性有机质(dissolved organic matter, DOM)是生物地球化学反应的重要驱动因子, 河口海湾水体DOM组分特征及其来源对海域生态环境具有重要影响。钦州湾是典型的亚热带半封闭的河口型海湾, 由内湾(茅尾海)和外湾共同组成, 平陆运河借由钦江入茅尾海。本文以平陆运河-钦州湾入海口为研究区域, 综合运用紫外-可见吸收光谱与三维荧光光谱-PARAFAC分析技术, 系统探究了水体中溶解有机质(DOM)的组分特征及来源。研究结果表明, 钦州湾表层水体溶解有机碳(DOC)年范围为1.8~9.1mg·L-1。其中, 2025年2月浓度最低(平均2.11±0.38mg·L-1)在2024年10月浓度最高(平均7.53±1.43mg·L-1)。同时, 空间上呈现出从平陆运河河口向内湾口降低, 再向外湾递减的变化趋势。钦州湾水体中DOM识别出三种荧光组分, 即类腐殖质C1(Ex/Em=240/430nm)、类蛋白质C2(Ex/Em=245/300nm)和C3(Ex/Em=250, 275/350nm), 其中C2最大荧光强度(Fmax) 波动最大(58.03~37423.30 ), Fmax在2024年9月达到最高值为72279.81, 在2025年4月达到最低值8264.35。在2025年3—6月, DOM 类腐殖质组分(C1)相对占比高达60%~81%, 同时SUVA254(>3.5)和腐殖化指数(HIX)显著升高, 表明水体中DOM是由河流输送的大量芳香性强、腐殖化程度高的陆源类腐殖质; 2024年8月至2025年1月, 类蛋白组分(C2和C3)占比超过70%, SUVA254(<1.5)和HIX降至极低水平, 而生物源指数(BIX)升高, 此阶段以内源自生和人类源为主。相关性分析表明, 盐度与DOC浓度(r=-0.715, p<0.01)、类腐殖质组分C1(r=-0.777, p<0.01)和类酪氨酸组分C2(r=-0.541, p<0.05)均呈显著负相关, 表明陆源DOM主要通过河流输入。研究结果为理解人类活动影响下河口碳循环的演变提供了支持, 并为平陆运河建设及区域水环境管理与污染控制提供了参考依据。

关键词: 溶解有机质, 组分特征, 三维荧光光谱, 钦州湾, 平陆运河

Abstract: Dissolved organic matter (DOM) is a key driver of biogeochemical reactions. The characteristics and sources of DOM components in estuarine and coastal waters significantly influence the marine ecological environment. Qinzhou Bay is a typical semi-enclosed subtropical estuarine bay, comprising an inner bay (Maowei Sea) and an outer bay. The Pinglu Canal discharges into the Maowei Sea via the Qinjiang River. This study focused on the estuary of the Pinglu Canal-Qinzhou Bay system. By integrating ultraviolet-visible (UV-Vis) absorption spectroscopy and excitation-emission matrix (EEM) fluorescence spectroscopy coupled with parallel factor analysis (PARAFAC), we systematically investigated the compositional characteristics and sources of DOM in the water body. The results indicated that the dissolved organic carbon (DOC) concentration in the surface water of Qinzhou Bay ranged annually from 1.8 to 9.1mg·L-1. The lowest concentration was observed in February 2025 (average 2.11±0.38mg·L-1), while the highest occurred in October 2024 (average 7.53±1.43mg·L-1). Spatially, DOC exhibited a decreasing trend from the Pinglu Canal estuary towards the inner bay mouth, followed by a further decrease towards the outer bay. Three fluorescent components were identified in the DOM of Qinzhou Bay: humic-like C1 (Ex/Em = 240/430nm), protein-like C2 (Ex/Em = 245/300nm), and protein-like C3 (Ex/Em = 250, 275/350nm). The maximum fluorescence intensity (Fmax) of C2 showed the greatest fluctuation (58.03~37423.30). The Fmax reached its peak value of 72279.81 in September 2024 and its lowest value of 8264.35 in April 2025. From March to June 2025, the relative abundance of the humic-like component (C1) was high (60%~81%), accompanied by significantly elevated SUVA254 (>3.5) and humification index (HIX). This indicates that the DOM during this period was predominantly composed of terrestrial humic substances with high aromaticity and degree of humification, transported by riverine input. From August 2024 to January 2025, the combined abundance of the protein-like components (C2 and C3) exceeded 70%, SUVA254 decreased to very low levels (<1.5), HIX dropped significantly, while the biological index (BIX) increased. This stage was dominated by autochthonous and anthropogenic sources. Correlation analysis revealed significant negative correlations between salinity and DOC concentration (r=-0.715, p<0.01), the humic-like component C1 (r=-0.777, p<0.01), and the tyrosine-like component C2 (r=-0.541, p<0.05), indicating that terrestrial DOM is primarily introduced through riverine input. These findings provide support for understanding the evolution of estuarine carbon cycling under the influence of human activities and offer a scientific basis for the construction of the Pinglu Canal and regional water environment management and pollution control.

Key words: dissolved organic matter, component characteristics, three dimensional fluorescence spectroscopy, Qinzhou Bay, Pinglu Canal