| 摘要: |
| 基于2021年4月至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。在时间上，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。在空间上，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:国家自然科学基金项目（面上项目，重点项目，重大项目）；山东省自然科学基金项目 |
附件 |
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| STUDY ON THE SEASONAL VARIATION OF DISSOLVED OXYGEN CONCENTRATION IN THE BOTTOM LAYER OF MARINE RANCHES IN THE 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;2.College of Oceanic,Zhejiang University
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| Abstract: |
| Based on the long-term observed data of 4 consecutive stations in the northern Ocean pasture area 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. In terms of time, the DO of the bottom layer gradually decreased from spring to summer, and gradually increased from summer to autumn, which was mainly controlled by temperature. The DO of all stations reached the lowest value in August, which was influenced by the vertical stratification and the increase of underlying biochemical oxygen consumption. Spatially, the DO concentration in the bottom layer 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 provides DO to the bottom. Moreover, the water depth in the south was shallower, so DO was more likely to reach saturation or susaturated state, while DO was still in the unsaturated state in the deeper water depth. The greater concentration of DO in the south than in the north in summer was caused by the spatial difference of seasonal stratification intensity. Meanwhile, the lower concentration of DO in the south decreases faster, which reduced the difference between the north and the south in summer. In mid-November, the bottom DO of the three offshore observation stations increased rapidly, which may be due to the reproduction of phytoplankton caused by the previous gale process, and the increase of DO in seawater due to the promotion of photosynthesis in clear weather. After that, the sea stratification disappeared and the sea water was sufficiently vertically mixed so that abundant DO reached the bottom |
| Key words: marine ranch bottom dissolved oxygen concentrations seasonal seawater stratification biochemical processes |