海洋学研究 ›› 2023, Vol. 41 ›› Issue (2): 94-103.DOI: 10.3969/j.issn.1001-909X.2023.02.008

• 研究论文 • 上一篇    下一篇

222Rn指示北部湾北部近海SGD输送的时空特征初探

佀祥城1,2(), 陈晓1,2, 陈法锦1,2, 金广哲1,2,*(), 师梓洋1,2, 谢旭峰1,2, 才华3   

  1. 1.广东海洋大学 海洋与气象学院,近海海洋变化与灾害预警实验室,广东 湛江 524088
    2.广东海洋大学 海洋与气象学院,广东省高等学校陆架及深远海气候、资源与环境重点实验室,广东 湛江 524088
    3.辽宁省公共资源交易中心,辽宁 沈阳 110031
  • 收稿日期:2022-03-30 修回日期:2022-10-18 出版日期:2023-06-15 发布日期:2023-07-27
  • 通讯作者: *金广哲(1982—),男,副教授,主要从事海底地下水排泄对近海环境和营养盐迁移转化的影响方面的研究, E-mail:jinguangzhe@live.cn
  • 作者简介:佀祥城(2000—),男,河南省濮阳市人,主要从事近海陆架区海水-地下水交互方面的研究,E-mail:1532522589@qq.com
  • 基金资助:
    国家自然科学基金项目(U1901213);国家自然科学基金委共享航次项目(NORC2021-11);广东省自然科学基金项目(2019B1515120066);广东省自然科学基金项目(2016A030312004);南方海洋科学与工程广东实验室(湛江)项目(ZJW-2019-08);广东省普通高校创新团队项目(2019KCXTF021);广东省冲一流专项资金项目(080503032101);广东省冲一流专项资金项目(231420003);广东海洋大学大学生创新创业训练计划项目(CXXL2021143)

A preliminary investigation on the spatial and temporal distribution of submarine groundwater discharge in the northern Beibu Gulf as indicated by 222Rn activities

SI Xiangcheng1,2(), CHEN Xiao1,2, CHEN Fajin1,2, JIN Guangzhe1,2,*(), SHI Ziyang1,2, XIE Xufeng1,2, CAI Hua3   

  1. 1. Laboratory for Coastal Ocean Variation and Disaster Prediction, College of Ocean and Meteorology, Guangdong Ocean University, Zhanjiang 524088, China
    2. Key Laboratory of Climate, Resources and Environment in Continental Shelf Sea and Deep Sea of Department of Education of Guangdong Province, College of Ocean and Meteorology, Guangdong Ocean University, Zhanjiang 524088, China
    3. Liaoning Provincial Public Resources Trading Center, Shenyang 110031, China
  • Received:2022-03-30 Revised:2022-10-18 Online:2023-06-15 Published:2023-07-27

摘要:

放射性同位素氡222 (222Rn) 是来源于地层中铀衰变生成的惰性元素。由于其性质稳定,容易测量且在地下水和地表水中活度差异显著,近年来被用作示踪剂广泛应用在海底地下水排泄(submarine groundwater discharge,SGD)的研究中。本文选取北部湾北部海水的222Rn活度作为研究对象,通过2021年8月—9月以及12月—次年1月在北部湾北部海域的两个航次采样,分析了北部湾北部海域水体222Rn的空间分布和季节性变化特征,并结合222Rn的质量平衡模型,估算了北部湾北部海域的SGD通量。结果表明,222Rn分布特征受到季节变化和陆源SGD过程的显著影响,冬季222Rn活度的平均值与夏季相比减少了约40%。夏季底层水222Rn活度较高,断面特征显示SGD过程明显且多集中于研究区北部,而冬季底层水222Rn活度较低,断面特征显示SGD过程较弱。通过构建222Rn质量平衡模型,估算出北部湾北部海域夏季与冬季SGD速率分别为4.16 cm·d-1和2.88 cm·d-1。夏季SGD速率明显高于冬季,且夏季以近岸SGD过程为主,冬季以离岸SGD为主。北部湾北部海域存在着明显的SGD过程,而且由于该区域被陆地和岛屿三面环绕,SGD过程很可能是陆源物质向近岸海域输送的重要自然途径。

关键词: 海底地下水排泄(SGD), 氡同位素(222Rn), 质量平衡模型

Abstract:

The radioactive isotope radon-222(222Rn) is an inert element derived from the decay of uranium in the earth’s strata. Due to its stability, ease of measurement and significant difference in activity between groundwater and surface water, it has been widely used as a tracer in the study of submarine groundwater discharge (SGD) in recent years. In this study, the 222Rn activity of seawater was selected as the object of study, and the spatial and temporal characteristics of 222Rn were analyzed, and the SGD flux was estimated through a 222Rn mass balance model, based on two cruises of August-September, 2021 and December, 2021-January, 2022 from the northern Beibu Gulf. The results show a spatial and temporal variation of 222Rn distribution which was significantly affected by the terrestrial SGD process. The mean 222Rn activity decreased by about 40% in winter compared with that in summer. In summer, there show high 222Rn activity in bottom water especially from the northern part of the research area with a strong SGD process, but with low 222Rn activity in winter with weak SGD process. Based on the 222Rn mass balance model, the SGD fluxes of 4.16 cm·d-1 in summer and 2.88 cm·d-1 in winter were calculated from the research area, which shows significantly high SGD flux in summer dominant with nearshore SGD and low SGD flux in winter dominant with offshore SGD. Since the research area is surrounded by land and islands, the SGD processes were likely to be an important natural pathway for the terrestrial sources transporting to the nearshore waters.

Key words: submarine groundwater discharge (SGD), radon isotope (222Rn), mass balance model

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