| 摘要: |
| 陆源物质与海洋自生有机物在河口近海交汇、迁移与转化，显著影响河口碳循环过程。目前国内关于河口碳酸盐体系的研究主要集中在中大型河口（如长江口、黄河口、珠江口和九龙江口 等）。然而，针对热带岛屿小型河口的研究还鲜见报道。研究选取海南岛万泉河口为研究区域，分 别在丰水期和枯水期调查了表层水温度、盐度、总溶解无机碳（DIC）和总碱度（TA）的空间分 布特征，探讨了碳酸盐体系的影响因素。研究结果显示，万泉河口表层水体中 DIC 和 TA 的变化范围较大， 分别为 433 ～ 1 995 µmol/kg 和 454 ～ 2 324 µmol/kg。在空间上， 两个时期的表层水盐度、DIC 和 TA 由万泉河向外海递增。与丰水期相比，枯水期表层水具有较低的温度，较高的盐度、DIC 和 TA。两个时期的 DIC、TA 和盐度呈显著正相关关系，推测河口咸淡水混合过程是影响 DIC 和 TA 时空分布的重要因素。此外，在丰水期，河口内存在 DIC 和 TA 添加的现象；枯水期，河口中的盐度区存在 TA 去除和 DIC 添加的现象。根据非保守 TA 和 DIC 的比值推测，研究区域碳酸盐体系的非保守行为主要受生物呼吸作用和碳酸钙生成 / 溶解过程的影响。文章探讨了万泉河口碳酸盐体系的季节变化和主要影响过程，能够为区域碳收支的构建提供数据和理论 支撑。 |
| 关键词: 总碱度 总溶解无机碳 碳酸盐体系 非保守性行为 水团混合 万泉河口 |
| DOI：10.20016/j.cnki.hykfygl.2025.10.010 |
| 投稿时间：2025-04-10修订日期：2025-08-21 |
| 基金项目:南海局科技发展基金项目（240101）；国家海洋局南海分局海洋科学技术局长基金资助项目（1542）. |
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| Carbonate System and Its Controlling Mechanisms in Tropical Island Estuaries |
| YUAN Chao,WANG Dehong,REN Maoxing,HAN Liuyu,XU Ge |
| Haikou Marine Center，MNR;Nansha Islands Coral Reef Ecosystem National Observation and Research Station |
| Abstract: |
| The confluence，migration and transformation of terrestrial material and marine authigenic organic matter in the estuary and offshore significantly affect the estuarine carbon cycle process.In the surface waters of the Wanquan River Estuary，an investigation was conducted into the distribution and interrelation of water temperature，salinity，dissolved inorganic carbon（DIC），and totalalkalinity（TA）．Furthermore，the mechanism governing the distribution of carbonates was discussed．During both high-flow and rainless periods， the concentrations of these parameters were measured，and their spatiotemporal distribution and relationships were evaluated．In the surface waters of the Wanquan River Estuary，the concentrations of DIC and TA exhibited wide fluctuations，ranging from 433 µmol/kg to 1 995 µmol/kg and from 454 µmol/kg to 2 324 µmol/kg，respectively． The water temperature was evenly distributed，while salinity，DIC，and TA increased spatially from the estuary towards the sea．Strong positive linear correlations were observed between DIC and TA，as well as between these parameters and salinity． During the high-flow period，deficiencies in DIC and TA were noted in low-salinity areas（＜ 10），with conservative behaviors occurring else where；during the rainless period，however，conservative behaviors were observed throughout the study area．The distribution characteristics and conservative behavior of carbonates in the study area were primarily influenced by the interaction of water masses，biological absorption，super saturation settlement of calcium carbonate， and the influx of high-DIC water from the Qiongdong upwelling．Additionally，the differences in carbonate conservation behavior between the high-flow and rainless periods were mainly attributed to river runoff and the carbonate content of the river itself．This study discusses the seasonal changes and main influencing processes of the carbonate system in the Wanquan River Estuary，which can provide data and theoretical support for the construction of a regional carbon budget. |
| Key words: Total alkalinity（TA）,Dissolved inorganic carbon（DIC）,Carbonate system,Conservative behavior,Interaction between water masses,Wanquan River estuary |
