氨基酸示踪南海东北部溶解有机物的来源与降解状态

迟隆祥; 范承飞; 陈岩; 张洪海

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中国环境科学 ›› 2025, Vol. 45 ›› Issue (9) : 5062-5070.

环境生态

氨基酸示踪南海东北部溶解有机物的来源与降解状态

迟隆祥^1,2, 范承飞^1,2, 陈岩², 张洪海^1,2

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Amino acid traced the source and degradation state of dissolved organic matter in the Northeastern South China Sea

CHI Long-xiang^1,2, FAN Cheng-fei^1,2, CHEN Yan², ZHANG Hong-hai^1,2

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摘要

于2023年9月调查了南海东北部海域海水中总溶解态氨基酸(TDAA)的浓度分布、分子组成并探究了溶解有机物(DOM)的来源及降解状态.结果表明:海水中TDAA的浓度范围为0.37~2.59μmol/L,平均值为(0.78±0.41)μmol/L,TDAA的水平分布呈现近岸高、远海低的特点,垂直分布呈现表层至底层逐渐降低的趋势.以D-丙氨酸(D-Ala)作为生物标志物量化细菌源有机物对DOM的贡献率(Bacterial-C%),海水中Bacterial-C%的变化范围为9.6%~46.2%,平均值为(23.3±8.1)%,其整体呈现近岸低、远海高的趋势.此外,表层海水的降解因子(DI)平均值为(0.5±1.0),而中层海水和底层海水DI的平均值分别为(-1.2±0.6)和(-1.3±0.6),表明表层海水的DOM相对于中层和底层海水的DOM降解程度较低.本研究揭示了南海东北部海域DOM的来源及降解状态,为深入理解边缘海生物地球化学循环过程提供了重要的科学依据与数据支持.

Abstract

In September 2023, a study was conducted in the Northeastern South China Sea to investigate the concentration distribution and mole composition of total dissolved amino acids (TDAA) in the seawater, as well as the sources and degradation status of dissolved organic matter (DOM). The results showed that the concentration of TDAA ranged from 0.37 to 2.59μmol/L, with an average value of (0.78±0.41) μmol/L. The horizontal distribution of TDAA exhibited a pattern of higher concentrations near the coast and lower concentrations in offshore, while the vertical distribution showed a gradual decrease from the surface to the bottom layer. Using D-alanine (D-Ala) as a biomarker, the contribution of bacterial organic matter to DOM (Bacterial-C%) was quantified. The Bacterial-C% in seawater ranged from 9.6% to 46.2%, with an average value of (23.3±8.1)%, demonstrating an overall trend of lower values near the coast and higher values in offshore areas. Additionally, the mean value of degradation index (DI) in surface seawater was (0.5 ± 1.0), while the average DI values for middle and bottom layers were (-1.2±0.6) and (-1.3±0.6), respectively. This indicates that the DOM in surface seawater was less degraded compared to those in the middle and bottom layers. This study elucidates the sources and degradation status of DOM in the Northeastern South China Sea, providing important scientific insights and data support for a deeper understanding of biogeochemical cycling processes in marginal seas.

导出引用

迟隆祥, 范承飞, 陈岩, 张洪海. 氨基酸示踪南海东北部溶解有机物的来源与降解状态[J]. 中国环境科学. 2025, 45(9): 5062-5070

CHI Long-xiang, FAN Cheng-fei, CHEN Yan, ZHANG Hong-hai. Amino acid traced the source and degradation state of dissolved organic matter in the Northeastern South China Sea[J]. China Environmental Science. 2025, 45(9): 5062-5070

中图分类号： X55

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