渤海底层低氧区的空间特征与形成机制

发布时间：2018-06-13 22:31

本文选题：渤海 + 低氧　；参考：《科学通报》2016年14期

【摘要】：近海低氧区的发生是影响海洋生态系统健康的重要因素,也是海洋科学的研究热点.通过对2014年渤海夏季(8月末)航次观测数据的深入分析及与春(4月末)、秋(11月)两季观测的对比,研究了半封闭的渤海底层低氧区的分布特征、形成机制、及其与温盐结构的关系.结果表明,春季和秋季渤海底部溶解氧(DO)8 mg/L,但在夏季出现大范围底部DO低值区,其中DO3 mg/L的低氧区总面积约为4.2×10~3km~2,具有南、北"双核"结构,空间特征与双中心冷水结构基本一致.渤海中部断面分析表明渤海浅滩南北两侧洼地在夏季出现明显垂向分层,导致底部冷水团DO含量下降与明显酸化(p H7.8).冷水区稳定的沉积环境使其表层沉积物总有机碳(TOC)和总有机氮(TON)含量明显高于其他海区.对数据综合分析表明,渤海中部海水季节性层化及其对溶氧的阻滞作用是低氧区产生的关键物理机制,沉积物中累积的有机质在夏季的矿化分解是产生底部低氧和酸化环境的重要原因.该低氧区的产生是渤海生态系统剧变的结果和集中体现,与赤潮等生态灾害频繁发生和渔业资源衰退可能存在密切关系.
[Abstract]:The occurrence of offshore hypoxia is an important factor affecting the health of marine ecosystem, and it is also a hot research topic in marine science. Based on the deep analysis of the observation data of the Bohai Sea in the summer of 2014 and its comparison with the observations in late April and autumn (November), the distribution characteristics and formation mechanism of the semi-closed low oxygen region in the bottom of the Bohai Sea are studied. And its relationship with the structure of temperature and salt. The results show that the do at the bottom of the Bohai Sea in spring and autumn is 8 mg / L, but in summer there is a wide range of low value regions of do in the bottom, in which the total area of the low oxygen region of do 3 mg / L is about 4.2 脳 10 3 km / L, which has a "binuclear" structure in the north and south of the Bohai Sea. The spatial characteristics are basically consistent with the double center cold water structure. The analysis of the middle section of the Bohai Sea shows that the vertical stratification appears in the north and south sides of the shallow beach of the Bohai Sea in summer, which leads to the decrease of do content in the bottom chilled water mass and the obvious acidification of P / H 7.8%. The contents of total organic carbon (TOC) and total organic nitrogen (TOC) in surface sediments of cold water zone are higher than those in other sea areas due to the stable sedimentary environment. The comprehensive analysis of the data shows that seasonal stratification of seawater in the central Bohai Sea and its blocking effect on dissolved oxygen are the key physical mechanisms for the production of hypoxic zone. The mineralization and decomposition of organic matter accumulated in sediments in summer is an important cause of low oxygen and acidizing environment at the bottom. The occurrence of this low oxygen area is the result of the dramatic changes of the Bohai Sea ecosystem, which may be closely related to the frequent occurrence of ecological disasters such as red tide and the decline of fishery resources.
【作者单位】：中国科学院烟台海岸带研究所;
【基金】：中国科学院战略性先导专项(XDA11020305),中国科学院重点部署项目(KZZD-EW-14) 青年“千人计划”项目资助
【分类号】：X55

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