| 摘要: |
| 基于2021年4~12月山东半岛烟台-威海北部海洋牧场区域4处连续观测站的长期观测数据, 研究了该海域底层溶解氧(dissolved oxygen, DO)浓度的季节变化特征, 并探讨了物理机制。该海域底层DO从春季到夏季逐渐降低, 而从夏季到秋季逐渐升高, 主要受温度控制; 各观测站DO均在8月达到最低值, 受垂向层结增强和底层生物化学耗氧增多的共同影响。底层DO浓度在东西方向差异较小, 而在南北方向上差异明显; 在春季和秋季DO浓度南高北低, 是由于层结较弱, 海水垂向混合向底层提供DO, 且南边水深更浅, DO更容易达到饱和或过饱和状态, 而水深更深处DO仍处于不饱和状态; 夏季DO浓度南边大于北边是季节性层结强度的空间差异所致, 同时南边底层DO浓度下降更快, 使其南北差异在夏季有所减小。在11月中旬, 近岸3个观测站底层DO快速增多, 可能是由于此前的大风过程引起浮游植物繁殖, 晴朗天气促进其光合作用使海水中DO增多, 之后海水层结消失, 海水充分垂向混合使丰富的DO到达底层。 |
| 关键词: 海洋牧场 溶解氧浓度 季节性海水层结 生化过程 |
| DOI：10.11693/hyhz20221200317 |
| 分类号:P717 |
| 基金项目:山东省自然科学基金项目, ZR2020MD059号; 国家自然科学基金项目, 42176016号。 |
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| SEASONAL VARIATION OF DISSOLVED OXYGEN CONCENTRATION IN BOTTOM WATER OF MARINE RANCHES NORTH OF YANTAI-WEIHAI |
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FAN Si-Qi1, LIU Zi-Zhou1, ZHAI Fang-Guo1, GU Yan-Zhen2
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1.College of Oceanic and Atmospheric Sciences, Ocean University of China, Qingdao 266100, China;2.College of Oceanic, Zhejiang University, Zhoushan 316021, China
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| Abstract: |
| Based on the long-term observed data from four consecutive stations in marine ranch area north of Yantai and Weihai, Shandong Peninsula from April to December 2021, the dissolved oxygen (DO) concentration in the bottom was investigated, and the physical mechanism was discussed. The DO in the bottom water layer gradually decreased from spring to summer, and gradually increased from summer to autumn, which was mainly controlled by temperature. The DO at all the stations was the lowest in August, which was influenced by vertical stratification and the increase of underlying biochemical oxygen consumption. The DO concentration in the bottom water had a small difference in the east-west direction, but a significant difference in the north-south direction. In spring and autumn, the DO concentration was higher in the south and lower in the north, because the stratification was weak and the vertical mixing of seawater provided DO to the bottom. Moreover, the water depth in the south was shallower, thus DO was more likely to reach saturation, while DO in the deeper water depth remained in unsaturated state. In summer, caused by the spatial difference of seasonal stratification intensity, DO concentration in the south was higher than it in the north. Meanwhile, the DO concentration in the south decreased faster, which reduced the difference between the north and the south in summer. In mid-November, there was a rapid increase in DO at the three nearshore stations, which was possibly due to the phytoplankton bloom caused by previous strong wind process. And sunny weather promoted photosynthesis in phytoplankton, increasing DO in seawater. |
| Key words: marine ranch bottom dissolved oxygen concentration seasonal seawater stratification biochemical processes |
