春季长江口及其邻近海域海水和大气中CH_(3)I、CH_(2)Br_(2)和CHBr_(3)的浓度分布与海-气通量  

Distributions and Sea-to-Air Fluxes of CH_(3)I,CH_(2)Br_(2)and CHBr_(3)in the Yangtze River Estuary and Its Adjacent Marine Area in Spring

作　　者：綦倩倩 何真 杨桂朋[1,2] 汪浩 QI Qian-Qian;HE Zhen;YANG Gui-Peng;WANG Hao(College of Chemistry and Chemical Engineering, Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100, China;Laboratory for Marine Ecology and Environmental Science, Polit National Laboratory for Marine Science and Technology(Qingdao), Qingdao 266237, China)

机构地区：[1]中国海洋大学化学化工学院海洋化学理论与工程技术教育部重点实验室,山东青岛266100 [2]青岛海洋科学与技术试点国家实验室海洋生态与环境科学功能实验室,山东青岛266237

出　　处：《中国海洋大学学报（自然科学版）》2021年第6期59-69,共11页Periodical of Ocean University of China

基　　金：国家自然科学基金项目(41830534,41506088);国家重点研究发展计划项目(2016YFA0601304);中央高校基本科研业务费项目(201762030)资助。

摘　　要：测定了2018年春季长江口及其邻近海域海水和大气中碘甲烷(Iodomethane,CH_(3)I)、二溴甲烷(Dibromomethane,CH_(2)Br_(2))和溴仿(Tribromomethane,CHBr_(3))的浓度,研究其在海水和大气中的浓度分布特征,探讨了环境因素对其源汇和浓度分布的影响。调查海域海水中CH_(3)I、CH_(2)Br_(2)和CHBr_(3)的浓度分别为(5.76±2.50)、(5.38±3.31)和(4.65±3.50)pmol·L^(-1),总体呈现出近岸高,远岸低的趋势。调查海域CH_(3)I的浓度分布受浮游植物的影响显著;CH_(2)Br_(2)的分布是多种因素共同作用的结果,其中人为输入是影响CH_(2)Br_(2)浓度分布的重要因素之一;CHBr_(3)的浓度分布受人为输入和浮游植物产生释放的共同影响。垂直方向上,海水上下混合比较均匀,受长江冲淡水和沉积物释放的影响,CH_(3)I、CH_(2)Br_(2)和CHBr_(3)在表层和底层都观测到浓度高值。大气中CH_(3)I、CH_(2)Br_(2)和CHBr_(3)浓度分别是(1.06±0.77)、(1.72±1.22)和(1.97±2.12)pptv,总体上呈现近岸高于远岸的趋势,人为排放、海-气交换和气团活动共同影响了大气中挥发性卤代烃(Volatile halocarbons,VHCs)的浓度分布,大气中的CH_(2)Br_(2)和CHBr_(3)存在多种来源,不同来源之间CH_(2)Br_(2)和CHBr_(3)排放比率存在较大差异。CH_(3)I、CH_(2)Br_(2)和CHBr_(3)的海-气通量分别为(50.21±45.47)、(-1.76±77.43)和(-37.65±87.07)nmol·(m^(2)·d)^(-1),表明调查期间长江口及其邻近海域是CH_(3)I的源,同时也是CHBr_(3)和CH_(2)Br_(2)的汇。Seawater and atmosphere concentrations of the three volatile halocarbons(VHCs),methyl iodide(CH_(3)I),dibromomethane(CH_(2)Br_(2))and bromoform(CHBr_(3))were investigated along with main controlling factors in the Yangtze River Estuary and its adjacent marine area during 9 March 2018 to 24 March 2018.Concentrations of CH_(3)I,CH_(2)Br_(2)and CHBr_(3)in the surface seawater were(5.76±2.50),(5.38±3.31)and(4.65±3.50)pmol·L^(-1).The concentration distributions of the three VHCs generally decreased from inshore to offshore regions except for a few high-value stations of CH_(2)Br_(2)in the open sea.Phytoplankton release was an important source of CH_(3)I,while human input was one of the factors affecting the concentration of CH_(2)Br_(2).Our results also suggest that distribution of CHBr_(3)was influenced by human activities and phytoplankton release might contribute to CHBr_(3)concentration maxima in the surface water.Vertical distributions showed high concentrations of CH_(3)I,CH_(2)Br_(2)and CHBr_(3)in the surface and bottom layers due to the impact of Changjiang input and sediments release.The mean mixing ratios of CH_(3)I,CH_(2)Br_(2)and CHBr_(3)in the atmosphere were(1.06±0.77),(1.72±1.22)and(1.97±2.12)pptv.Elevated concentrations of the three VHCs in the atmosphere were observed in coastal areas.These results may be related to the influence of anthropogenic release,sea-air exchange and air mass activities.The CH_(2)Br_(2)/CHBr_(3)ratios in the atmosphere indicated that the emission ratios of CHBr_(3)and CH_(2)Br_(2)between different sources were various.The sea-to-air fluxes of CH_(3)I,CH_(2)Br_(2)and CHBr_(3)were(50.21±45.47),(-1.76±77.43)and(-37.65±87.07)nmol·(m^(2)·d)^(-1),which indicated that the Yangtze River Estuary was the source of CH_(3)I,but the sink of CHBr_(3)and CH_(2)Br_(2).

关 键 词：挥发性卤代烃 长江口 分布 来源 海-气通量 

分 类 号：P734[天文地球—海洋化学]