Tracing surface seawater mixing and nutrient transport by^(222)Rn on the northern coast of Beibu Gulf,China

查看全文 作　　者：Hao [1,2,3]Wang;Qiangqiang [2,3]Zhong;Fule [2,3]Zhang;Suiyuan [2,3]Chen;Hongyan [4]Bao;Jing [2,3]Lin;Dekun [2,3]Huang;Tao [2,3]Yu 机构地区：[1]College of Marine Sciences,Shanghai Ocean University,Shanghai 201306,China;[2]Third Institute of Oceanography,Ministry of Natural Resources,Xiamen 361005,China;[3]Observation and Research Station of Coastal Wetland Ecosystem in Beibu Gulf,Ministry of Natural Resources,Beihai 536015,China;[4]State Key Laboratory of Marine Environmental Science,College of Ocean and Earth Sciences,Xiamen University,Xiamen 361102,China 出　　处：《Acta Oceanologica Sinica》索引2023年第42卷第8期,共12页 基　　金：The Scientific Research Foundation of the Third Institute of Oceanography,Ministry of Natural Resources under contract Nos 2023007 and 2020017;the Natural Science Foundation of Fujian Province under contract No.2020J05010;the Foundation of Xiamen Institute of Marine Development under contract No.KFY202204;the Asian Cooperation Fund Project-Study on Typical Bay Ecological Protection and Management Demonstration. 摘　　要：The transport and diffusion of substances in seawater are limited by the mixing motion of water bodies,while the main forms of mixing in offshore water bodies are advection and eddy diffusion.The eddy diffusion process of water indicates the possible transport direction of dissolved substances.However,the complex environment in the coastal zone makes it difficult to quantitatively assess the water diffusion process.^(222)Rn is a useful tool to trace the diffusion process of water bodies.However,studies on the^(222)Rn distribution and its behavior in the Beibu Gulf are scarce.In this study,the activity distribution characteristics of^(222)Rn in surface seawater of the Guangxi shelf area of the Beibu Gulf were measured.Based on the one-dimensional,steady-state model,the vorticity diffusion coefficient of^(222)Rn in the horizontal direction was calculated as(0.42−2.13)×10^(8) m^(2)/d,and the offshore fluxes of^(222)Rn under the influence of water mixing were calculated as 2.00×10^(12) Bq/d.Correspondingly,the horizontal transport fluxes of silicate,phosphate,nitrite and nitrate were 6.28×10^(−3)mol/(m^(2)·d),0.10×10^(−3)mol/(m^(2)·d),0.20×10^(−3)mol/(m^(2)·d)and 4.15×10^(−3)mol/(m^(2)·d),respectively.These results indicate that the study of eddy current diffusion in offshore marine water facilitates a deeper understanding of the water mixing process and nutrient transport and migration. 关 键 词：^(222)Rn water mixing NUTRIENTS vorticity diffusion coefficient horizontal transport flux