孙利元¹, 刘子洲², 丁金强¹, 翟方国², 顾艳镇²
1.山东省渔业发展和资源养护总站, 山东 烟台 264003;2.中国海洋大学 海洋与大气学院, 山东 青岛 266100

摘要:
基于2020年夏季的大面航次观测数据，分析了烟台—威海北部海洋牧场及邻近海域海水溶解氧浓度垂向分布最小值（氧最小值层）的空间分布特征，并探讨了影响因素。从6月至8月，海水溶解氧浓度不断减小，垂向结构亦存在显著变化。海水溶解氧浓度垂向分布的最小值主要集中于7月的近岸海域，最小值大致从外海向近岸方向减小，其距离海底高度及与底层溶解氧浓度之差的绝对值均于双岛湾邻近海域为最大。海水溶解氧浓度垂向分布的最小值位于最强密度层结以下。但是海水溶解氧浓度垂向分布最小值的强度向北减小，而密度层结向北增大，两者的空间分布基本相反，说明密度层结抑制垂向湍流扩散可极大减少深层海水溶解氧的来源，是海水溶解氧浓度垂向分布最小值形成的必要条件，但不是主导因素。在海水溶解氧浓度垂向分布的最小值层，表观耗氧量存在垂向分布的最大值，大部分站点的pH存在垂向分布的最小值，说明局地增强、持续的生物地球化学耗氧是控制海水溶解氧浓度垂向分布最小值形成和空间分布的一个重要过程。研究结果表明氧最小值层是夏季烟台—威海北部近岸海水溶解氧垂向结构的典型特征之一。
关键词:烟台—威海北部近海海水溶解氧浓度垂向分布的最小值表观耗氧量pH
DOI：10.11759/hykx20210412002
分类号:P715
基金项目:山东省自然科学基金项目（ZR2020MD059）；国家自然科学基金项目（42176016）；浙江省重点研发计划（2020C03012）；广东省重点研发计划（2020B1111030002）；三亚崖州湾科技城管理局重大科技项目（SKJC-KJ-2019KY03）；国家重点研发计划（2019YFD0901305）

Minima in vertical distributions of dissolved oxygen concentration in the northern coastal oceans of Yantai-Weihai
SUN Li-yuan¹, LIU Zi-zhou², DING Jin-qiang¹, ZHAI Fang-guo², GU Yan-zhen²
1.Shandong Fisheries Development and Resources Conservation Center, Yantai 264003, China;2.College of Oceanic and Atmospheric Sciences, Ocean University of China, Qingdao 266100, China
Abstract:
The present study investigates the spatial distribution of minima of dissolved oxygen (DO) concentration in vertical distributions (oxygen minimum layer) and the influencing factors in the northern coastal oceans of Yantai-Weihai based on cruise observations recorded in 2020's summer. From June to August, the DO concentration decreased, and its vertical distribution changed significantly. In July, DO concentration minima in the vertical distributions were observed primarily in nearshore regions and decreased shoreward; its height above the sea bottom and difference from the bottom layer DO concentration were the largest in Shuangdao Bay. Besides, DO concentration minima in the vertical distributions were located below the strongest density stratification. However, the strength of DO concentration minima decreased northward, and this was opposite to density stratification, which increased northward. This finding indicated that density stratification could significantly restrict oxygen from entering the bottom layer of water by inhibiting turbulence-induced vertical diffusion. Thus, it was necessary but not a dominant factor for the formation of the oxygen minimum layer. Apparent oxygen utilization had maxima and pH had minima in the DO minimum layers at most observation sites. This high degree of correlation suggested that locally enhanced and continuous biogeochemical oxygen consumption were important in controlling the formation and spatial distribution of the oxygen minimum layer. The present study indicated that the oxygen minimum layer is one of the prominent features in vertical distributions of DO in nearshore waters of northern Yantai-Weihai.
Key words:northern coastal oceans of Yantai-Weihaidissolved oxygen concentrationminimum in vertical distributionapparent oxygen utilizationpH





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