秋季南海北部溶解态锰的分布及其影响因素  

Distribution and influencing factors of dissolved manganese in the northern South China Sea in autumn

作　　者：王政委 张媛 杨一超 陈晶 任景玲[1] Wang Zhengwei;Zhang Yuan;Yang Yichao;Chen Jing;Ren Jingling(Key Laboratory of Marine Chemistry Theory and Technology,Ministry of Education,Ocean University of China,Qingdao 266100,China)

机构地区：[1]中国海洋大学海洋化学理论与工程技术教育部重点实验室,山东青岛266100

出　　处：《海洋学报》2024年第7期120-130,共11页

基　　金：国家自然科学基金(42176042);山东省泰山学者工程专项。

摘　　要：利用在线富集−流动注射分析方法测定了2017年10月珠江口−琼东海域和2020年9月南海东北部−中部海域(文中将两个航次研究区域统称南海北部)溶解态锰(dMn)的浓度。研究结果显示,南海北部dMn的浓度范围为0.7~8.6 nmol/L,平均浓度为(2.6±1.3)nmol/L。dMn浓度的平面分布整体呈现近岸高、外海低的特点,琼东沿岸及珠江口海域dMn的浓度高于南海北部陆坡及中部海域。dMn的垂直分布呈现表层高,随深度增加逐渐降低,DO相对较低的中层水体dMn浓度升高,深层水dMn浓度较低。影响南海dMn分布的因素主要包括水团混合、颗粒物吸附−解吸和低氧环境再生。富Mn陆架水沿上层(<80 m)向南海北部陆架海域输送。以盐度和dMn作为示踪剂研究2020年秋季黑潮次表层水对南海的入侵,结果发现入侵主要集中在24.5~25.0 kg/m^(3)密度面上,向西延伸到117.5°E,向南延伸到20°N。南海中部中层水体(400~1500 m,DO浓度<100μmol/L)dMn浓度升高,dMn浓度与表观耗氧量(AOU)呈正相关关系,说明低氧环境再生影响南海北部dMn的分布。The concentrations of dissolved manganese(dMn)in the Zhujiang Estuary-Qiongdong Sea area in October 2017 and the northeast-central part of the South China Sea(SCS)in September 2020(the research areas are referred to as the northern South China Sea,NSCS)were determined by online concentration-flow injection analysis.The results showed that the concentration of dMn in the NSCS ranged from 0.7 nmol/L to 8.6 nmol/L,with an average of(2.6±1.3)nmol/L.The concentration of dMn was higher in the coastal area and decreased with distance from the coast,dMn in the Zhujiang Estuary-Qiongdong Sea area was higher than that in the northern and central of the SCS.The vertical profiles of dMn normally was highest in the surface layer,gradually decreased with depth and increased dMn in the intermediate water with relatively low dissolved oxygen,and then kept low concentration in the deep water.The factors affecting the distribution of dMn in the NSCS mainly include water mass mixing,particulate adsorption-desorption and regeneration in low oxygen environment etc.Mn-rich shelf water was transported to the slope of NSCS along the upper layer(<80 m).Using salinity and dMn as tracer to study the intrusion of Kuroshio subsurface water(KSSW)into the SCS in autumn 2020,the results showed that the KSSW intrusion was mainly concentrated at the potential density surfaces of 24.5~25.0 kg/m^(3),and the intrusion scope extending to 117.5°E in the west and 20°N in the south.The concentration of dMn in the intermediate water of the central SCS(400~1500 m,DO<100μmol/L)increased,and the concentration of dMn was positively correlated with apparent oxygen consumption(AOU),which indicated that remineralization process in low oxygen environment(DO<100μmol/L)affected the distribution of dMn in the NSCS.

关 键 词：溶解态锰 分布 影响因素 南海北部 

分 类 号：P714.1[天文地球—海洋科学]