Spatial-Monthly Variations and Influencing Factors of Dissolved Oxygen in Surface Water of Zhanjiang Bay, China
Dissolved oxygen (DO) is one of the most important factors for maintaining a healthy marine ecosystem. The information of DO in large estuaries or bays with large entrances has been widely studied, while it is relatively limited for a bay with a narrow entrance which is vulnerable to human activitie...
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MDPI AG
2020-06-01
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| Series: | Journal of Marine Science and Engineering |
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| Online Access: | https://www.mdpi.com/2077-1312/8/6/403 |
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| author | Fengxia Zhou Xuan Lu Fajin Chen Qingmei Zhu Yafei Meng Chunqing Chen Qibin Lao Shuwen Zhang |
| author_facet | Fengxia Zhou Xuan Lu Fajin Chen Qingmei Zhu Yafei Meng Chunqing Chen Qibin Lao Shuwen Zhang |
| author_sort | Fengxia Zhou |
| collection | DOAJ |
| description | Dissolved oxygen (DO) is one of the most important factors for maintaining a healthy marine ecosystem. The information of DO in large estuaries or bays with large entrances has been widely studied, while it is relatively limited for a bay with a narrow entrance which is vulnerable to human activities. The Zhanjiang Bay, located in the northwestern South China Sea, has a very narrow entrance and suffers from strong anthropogenic activities and obvious seasonal variations in environmental parameters. In this study, we analyzed the spatial and monthly variations of DO, apparent oxygen utilization (AOU), percent oxygen saturation (DO-saturation), and related environmental parameters in the surface water of Zhanjiang Bay to find out the factors controlling the dynamics of DO. Different from many other coastal ecosystems, DO concentrations in the Zhanjiang Bay reached minimum values in late spring and early autumn. The phytoplankton bloom in summer months, which was related to the high concentrations of nutrients brought by rainfall-induced terrestrial inputs, contributed to that phenomenon. Though high chlorophyll a (Chl <i>a</i>) concentrations were observed in both the summer months and December, the DO-saturation values were relatively low and AOU values were relatively high in summer months. Rainfall-induced terrestrial discharge in summer months, which had high concentrations of chemical oxygen demand, contributed much to that phenomenon. The average DO concentrations and DO-saturation values in a hydrological year decreased seaward, and AOU values increased seaward, indicating the anthropogenic influence from terrestrial input. The highest annual average Chl <i>a</i> concentration, relatively high annual average DO-saturation value and relatively low annual AOU value were observed near the Donghai Dam. This indicated that the construction of Donghai Dam has significant influences on the environment of Zhanjiang Bay. |
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| language | English |
| last_indexed | 2024-03-10T19:25:32Z |
| publishDate | 2020-06-01 |
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| series | Journal of Marine Science and Engineering |
| spelling | doaj.art-c81ae7ef498e497e8815f11c18009cf22023-11-20T02:36:52ZengMDPI AGJournal of Marine Science and Engineering2077-13122020-06-018640310.3390/jmse8060403Spatial-Monthly Variations and Influencing Factors of Dissolved Oxygen in Surface Water of Zhanjiang Bay, ChinaFengxia Zhou0Xuan Lu1Fajin Chen2Qingmei Zhu3Yafei Meng4Chunqing Chen5Qibin Lao6Shuwen Zhang7College of Ocean and Meteorology, Guangdong Ocean University, Zhanjiang 524088, ChinaCollege of Ocean and Meteorology, Guangdong Ocean University, Zhanjiang 524088, ChinaCollege of Ocean and Meteorology, Guangdong Ocean University, Zhanjiang 524088, ChinaCollege of Ocean and Meteorology, Guangdong Ocean University, Zhanjiang 524088, ChinaCollege of Ocean and Meteorology, Guangdong Ocean University, Zhanjiang 524088, ChinaCollege of Ocean and Meteorology, Guangdong Ocean University, Zhanjiang 524088, ChinaMarine Environmental Monitoring Center of Beihai, State Oceanic Administration, Beihai 536000, ChinaInstitute of Marine Science, Shantou University, Shantou 515063, ChinaDissolved oxygen (DO) is one of the most important factors for maintaining a healthy marine ecosystem. The information of DO in large estuaries or bays with large entrances has been widely studied, while it is relatively limited for a bay with a narrow entrance which is vulnerable to human activities. The Zhanjiang Bay, located in the northwestern South China Sea, has a very narrow entrance and suffers from strong anthropogenic activities and obvious seasonal variations in environmental parameters. In this study, we analyzed the spatial and monthly variations of DO, apparent oxygen utilization (AOU), percent oxygen saturation (DO-saturation), and related environmental parameters in the surface water of Zhanjiang Bay to find out the factors controlling the dynamics of DO. Different from many other coastal ecosystems, DO concentrations in the Zhanjiang Bay reached minimum values in late spring and early autumn. The phytoplankton bloom in summer months, which was related to the high concentrations of nutrients brought by rainfall-induced terrestrial inputs, contributed to that phenomenon. Though high chlorophyll a (Chl <i>a</i>) concentrations were observed in both the summer months and December, the DO-saturation values were relatively low and AOU values were relatively high in summer months. Rainfall-induced terrestrial discharge in summer months, which had high concentrations of chemical oxygen demand, contributed much to that phenomenon. The average DO concentrations and DO-saturation values in a hydrological year decreased seaward, and AOU values increased seaward, indicating the anthropogenic influence from terrestrial input. The highest annual average Chl <i>a</i> concentration, relatively high annual average DO-saturation value and relatively low annual AOU value were observed near the Donghai Dam. This indicated that the construction of Donghai Dam has significant influences on the environment of Zhanjiang Bay.https://www.mdpi.com/2077-1312/8/6/403dissolved oxygenanthropogenic influencesseasonal variationsZhanjiang Bay |
| spellingShingle | Fengxia Zhou Xuan Lu Fajin Chen Qingmei Zhu Yafei Meng Chunqing Chen Qibin Lao Shuwen Zhang Spatial-Monthly Variations and Influencing Factors of Dissolved Oxygen in Surface Water of Zhanjiang Bay, China Journal of Marine Science and Engineering dissolved oxygen anthropogenic influences seasonal variations Zhanjiang Bay |
| title | Spatial-Monthly Variations and Influencing Factors of Dissolved Oxygen in Surface Water of Zhanjiang Bay, China |
| title_full | Spatial-Monthly Variations and Influencing Factors of Dissolved Oxygen in Surface Water of Zhanjiang Bay, China |
| title_fullStr | Spatial-Monthly Variations and Influencing Factors of Dissolved Oxygen in Surface Water of Zhanjiang Bay, China |
| title_full_unstemmed | Spatial-Monthly Variations and Influencing Factors of Dissolved Oxygen in Surface Water of Zhanjiang Bay, China |
| title_short | Spatial-Monthly Variations and Influencing Factors of Dissolved Oxygen in Surface Water of Zhanjiang Bay, China |
| title_sort | spatial monthly variations and influencing factors of dissolved oxygen in surface water of zhanjiang bay china |
| topic | dissolved oxygen anthropogenic influences seasonal variations Zhanjiang Bay |
| url | https://www.mdpi.com/2077-1312/8/6/403 |
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