Spatiotemporal variations in the summer hypoxia in the Bohai Sea (China) and controlling mechanisms. (January 2019)

• Record Type: Journal Article
• Authors: Wei, Qinsheng; Wang, Baodong; Yao, Qingzhen; Xue, Liang; Sun, Junchuan; Xin, Ming; Yu, Zhigang
• Is Part Of: Marine pollution bulletin. Volume 138(2019)
• Page Start: 125
• Page End: 134
• Publication Date: 2019-01
• Subjects: Hypoxia -- Physical-biogeochemical mechanisms -- Eutrophication -- Bohai Sea; Marine pollution -- Periodicals; Marine Biology -- Periodicals; Water Pollution -- Periodicals; Mer -- Pollution -- Périodiques; Publications périodiques; Pollution des mers; Lutte antipollution; Electronic journals; 363.7394
• DOI: 10.1016/j.marpolbul.2018.11.041
• Languages: English
• ISSNs: 0025-326X

Abstract

Abstract: Based on field observations in the summer of 2006 and long-term series data, this paper investigates the spatiotemporal variations of hypoxia and associated physical-biogeochemical driving mechanisms in the Bohai Sea (BS), China. Results show that the benthic hypoxic zone is mainly distributed in the "V"-shaped trough region in the western BS, and it tends to form two hypoxic centers which generally correspond to the bottom cold-water core. The regional difference in the intensity of stratification has a significant impact on the spatial distribution of hypoxia. The relatively weak stratification and the mesoscale anticyclonic eddy in the central shoal of the BS weaken the connectivity between the southern and northern hypoxic zones. Organic matter decomposition contributes to hypoxia and results in corresponding nutrient pool with a "dual (southern and northern)-core" structure. Intensified eutrophication is the main drive for decreasing in bottom dissolved oxygen and expansion of hypoxic zone in the BS. Graphical abstract: Unlabelled Image Highlights: Bottom oxygen was decreasing and hypoxic zone was expanding in the Bohai Sea. Location of the hypoxia was controlled by topography and hydrodynamics. Nutrient pool with a "dual-core" structure existed in the hypoxic zone. Eutrophication was the main drive for decreasing in bottom dissolved oxygen.