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Liang W, Wang Y, Mu J, Wu N, Wang J, Liu S. Nutrient changes in the Bohai Sea over the past two decades. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 903:166696. [PMID: 37660818 DOI: 10.1016/j.scitotenv.2023.166696] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/15/2023] [Accepted: 08/28/2023] [Indexed: 09/05/2023]
Abstract
With the growing problem of eutrophication in the Bohai Sea, actions have been taken to reduce nutrient inputs, but it remains to be seen whether nutrient levels and structure have been ameliorated. In this study, the nutrient trends in the Bohai Sea are re-examined based on observations from 2000 to 2019. The results suggest that dissolved inorganic nitrogen (DIN) concentrations and DIN/DIP (dissolved inorganic phosphate) ratios gradually increased from 2000 to 2013 but dramatically decreased from 2013 to 2019. The increase and decrease rates of DIN concentrations decreased with increasing water depth, indicating that DIN concentrations in nearshore waters responded more rapidly to changes in human activities. However, DIP concentrations responded weakly to nutrient inputs, with their trends uncoupled. The DIN/DIP ratios have declined close to and in some seasons even below the canonical Redfield ratio in areas with water depths >20 m recently, implying that relative nutrient limitation in these areas may be shifting from relative phosphorus (P) limitation to absence of relative nutrient limitation or relative nitrogen (N) limitation. Atmospheric deposition, wastewater discharge, and riverine input were responsible for 66 %, 21 %, and 13 % of the variance in the decline of DIN concentration, respectively. Several environmental indicators responded positively to the decrease in DIN concentrations and DIN/DIP ratios, with varying degrees of recovery recently. Our study proves the phased success of various nutrient reduction measures taken by the Chinese government to improve the environment of the Bohai Sea over the past decade.
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Affiliation(s)
- Wen Liang
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, China
| | - Yan Wang
- National Marine Environmental Monitoring Center, Dalian, China
| | - Jinglong Mu
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, China
| | - Nian Wu
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Juying Wang
- National Marine Environmental Monitoring Center, Dalian, China.
| | - Sumei Liu
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
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Liu H, Ding C, Zhang G, Guo Y, Song Y, Thangaraj S, Zhang X, Sun J. Dissolved and particulate heavy metal pollution status in seawater and sedimentary heavy metals of the Bohai Bay. MARINE ENVIRONMENTAL RESEARCH 2023; 191:106158. [PMID: 37696163 DOI: 10.1016/j.marenvres.2023.106158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 08/08/2023] [Accepted: 08/29/2023] [Indexed: 09/13/2023]
Abstract
Heavy metal contamination has been the focus of many studies owing to its potential risk on the health of coastal ecosystems. The Bohai Bay (BHB) is the second largest bay of Bohai Sea and subjected to serious anthropogenic perturbations. The aim of this study was to evaluate the distribution and pollution status of toxic heavy metals in seawater with two fractions (dissolved and suspended particulate phases) and surface sediments of this coastal system. Therefore, several hydrochemical parameters and concentration of seawater metals and sediment metals were measured at two cruises of 2020 summer and autumn. The spatial distribution and potential ecological risks were examined and their inter-element relationships were analyzed to identify potential geochemical processes. By comparing historical data since 1978, we find declining trends in contents of most trace metals in seawater and sediments, suggesting that recent pollution control in BHB have an effect on diminishing metal pollution. Dissolved metals showed no significant dependence on their particulate phase. The seawater posed a moderate to high level of ecological risk. The hydrochemical factors mainly had a greater impact on dissolved metals during summer, whereas they influenced suspended metals more significantly during autumn. These results provide fundamental information to support environmental quality management and ecological protection in coastal systems.
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Affiliation(s)
- Haijiao Liu
- Tianjin Key Laboratory of Marine Resources and Chemistry, Tianjin University of Science and Technology, Tianjin, 300457, China
| | - Changling Ding
- Tianjin Key Laboratory of Marine Resources and Chemistry, Tianjin University of Science and Technology, Tianjin, 300457, China.
| | - Guicheng Zhang
- Tianjin Key Laboratory of Marine Resources and Chemistry, Tianjin University of Science and Technology, Tianjin, 300457, China
| | - Yiyan Guo
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Wuhan), Wuhan, 430074, China; College of Marine Science and Technology, China University of Geosciences (Wuhan), Wuhan, 430074, China
| | - Yuyao Song
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Wuhan), Wuhan, 430074, China; College of Marine Science and Technology, China University of Geosciences (Wuhan), Wuhan, 430074, China
| | - Satheeswaran Thangaraj
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Wuhan), Wuhan, 430074, China; College of Marine Science and Technology, China University of Geosciences (Wuhan), Wuhan, 430074, China; Department of Physiology, Saveetha Dental College and Hospital, Saveetha Institute of Medical & Technical Sciences, Saveetha University, Chennai, 600077, India
| | - Xiaodong Zhang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Wuhan), Wuhan, 430074, China; College of Marine Science and Technology, China University of Geosciences (Wuhan), Wuhan, 430074, China
| | - Jun Sun
- Tianjin Key Laboratory of Marine Resources and Chemistry, Tianjin University of Science and Technology, Tianjin, 300457, China; Research Centre for Indian Ocean Ecosystem, Tianjin University of Science and Technology, Tianjin, 300457, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Wuhan), Wuhan, 430074, China; College of Marine Science and Technology, China University of Geosciences (Wuhan), Wuhan, 430074, China.
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Shi Y, He Y, Shin PKS, Guo Y, Zhang G, Wen Y, Zhang G, Xu W, Sun J. Responses of biological traits of macrobenthic fauna to a eutrophication gradient in a semi-enclosed bay, China. MARINE ENVIRONMENTAL RESEARCH 2023; 189:106072. [PMID: 37385085 DOI: 10.1016/j.marenvres.2023.106072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 06/10/2023] [Accepted: 06/23/2023] [Indexed: 07/01/2023]
Abstract
The impacts of eutrophication on benthic ecological functions are of increasing concern in recent years. In order to assess the response of macrobenthic fauna to increasing eutrophication, two field sampling surveys were conducted during the summer (July-August 2020) and autumn (October-November 2020) from offshore, nearshore to estuarine sediments in Bohai Bay, northern China. Biological trait analysis was employed for the assessment of macrofaunal samples. The results indicated that there was an increase in the proportion of benthic burrowering or tube-dwelling sediment feeders and taxa with higher larval dispersal ability, but a decrease in the proportion of taxa showing high motility in areas with higher nutrient levels. Seasonal differences were also noted in the shift in biological traits, with a significantly lower similarity among the sampling areas in summer and a higher proportion of carnivorous taxa in autumn. The findings suggested that long-term disturbance can lead to the dominance of smaller body-sized benthic species and reduced sediment quality, impeding ecological recovery of benthic organisms under such harsh environment.
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Affiliation(s)
- Yifeng Shi
- Research Centre for Indian Ocean Ecosystem, Tianjin University of Science and Technology, Tianjin, 300457, China; Tianjin Key Laboratory of Marine Resources and Chemistry, Tianjin University of Science and Technology, Tianjin, 300457, China
| | - Yixuan He
- Research Centre for Indian Ocean Ecosystem, Tianjin University of Science and Technology, Tianjin, 300457, China; Tianjin Key Laboratory of Marine Resources and Chemistry, Tianjin University of Science and Technology, Tianjin, 300457, China
| | - Paul K S Shin
- Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong Special Administrative Region of China
| | - Yu Guo
- Research Centre for Indian Ocean Ecosystem, Tianjin University of Science and Technology, Tianjin, 300457, China; Tianjin Key Laboratory of Marine Resources and Chemistry, Tianjin University of Science and Technology, Tianjin, 300457, China
| | - Guodong Zhang
- Research Centre for Indian Ocean Ecosystem, Tianjin University of Science and Technology, Tianjin, 300457, China; Tianjin Key Laboratory of Marine Resources and Chemistry, Tianjin University of Science and Technology, Tianjin, 300457, China
| | - Yujian Wen
- Research Centre for Indian Ocean Ecosystem, Tianjin University of Science and Technology, Tianjin, 300457, China; Tianjin Key Laboratory of Marine Resources and Chemistry, Tianjin University of Science and Technology, Tianjin, 300457, China
| | - Guicheng Zhang
- Research Centre for Indian Ocean Ecosystem, Tianjin University of Science and Technology, Tianjin, 300457, China; Tianjin Key Laboratory of Marine Resources and Chemistry, Tianjin University of Science and Technology, Tianjin, 300457, China
| | - Wenzhe Xu
- Research Centre for Indian Ocean Ecosystem, Tianjin University of Science and Technology, Tianjin, 300457, China; Tianjin Key Laboratory of Marine Resources and Chemistry, Tianjin University of Science and Technology, Tianjin, 300457, China.
| | - Jun Sun
- Research Centre for Indian Ocean Ecosystem, Tianjin University of Science and Technology, Tianjin, 300457, China; Tianjin Key Laboratory of Marine Resources and Chemistry, Tianjin University of Science and Technology, Tianjin, 300457, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Wuhan), Wuhan, 430074, China; College of Marine Science and Technology, China University of Geosciences (Wuhan), Wuhan, 430074, China; Institute for Advanced Marine Research, China University of Geosciences, Guangzhou, 511462, China.
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Zhang F, Fu H, Lou H, Sun X, Zhang D, Sun P, Wang X, Li Y, Lu J, Bao M. Assessment of eutrophication from Xiaoqing River estuary to Laizhou Bay: Further warning of ecosystem degradation in typically polluted estuary. MARINE POLLUTION BULLETIN 2023; 193:115209. [PMID: 37364339 DOI: 10.1016/j.marpolbul.2023.115209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 06/17/2023] [Accepted: 06/20/2023] [Indexed: 06/28/2023]
Abstract
The coast of Laizhou Bay is plagued by a number of environmental issues, such as eutrophication, which are likely to worsen over the next few decades as a result of trends toward industrialization and urbanization. High nutrient levels in the Xiaoqing River are believed to be the main cause of Laizhou Bay becoming eutrophicated. Therefore, we conducted two cruises from the Xiaoqing River estuary to Laizhou Bay in August 2022 and December 2022, respectively, in the wet and dry periods to assess the potential impact of status of eutrophication due to human activities. The results showed that the concentration of DIN was higher than the quality standard for water (fi > 1) in both the wet season (August 2022) and the dry season (December 2022). DIN has major environmental impacts in Laizhou Bay. The eutrophication level index and organic pollution index have obvious spatial and temporal characteristics. In terms of time, the dry season is higher than the wet season. In space, Xiaoqing estuary is higher than Laizhou Bay. In the two surveys, DIN and DIP concentrations were significantly positively correlated, indicating that N and P pollution in the region had a common source and destination, and the spatial distribution was also similar. In addition, the current environmental conditions in the region are not ideal, reaching moderate and severe eutrophication levels, which proves that the ecosystem has the risk of aggravating degradation. As the Xiaoqing River is about to resume full navigation, human-related nutrient input (especially DIN) will continue to increase, and it is expected that the eutrophication risk in this area will increase in the next few years due to the increase in nutrient load.
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Affiliation(s)
- Feifei Zhang
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Institute for Advanced, Ocean Study, Ocean University of China, Qingdao 266100, China; College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China
| | - Hongrui Fu
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Institute for Advanced, Ocean Study, Ocean University of China, Qingdao 266100, China; College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China
| | - Huawei Lou
- Shouguang Marine Fishery Development Center, Weifang 262700, China
| | - Xiaojun Sun
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Institute for Advanced, Ocean Study, Ocean University of China, Qingdao 266100, China; College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China
| | - Dong Zhang
- Shouguang Marine Fishery Development Center, Weifang 262700, China.
| | - Peiyan Sun
- Key Laboratory of Ecological Warning, Protection & Restoration for Bohai Sea, Ministry of Natural Resources, Qingdao 266100, China
| | - Xinping Wang
- Key Laboratory of Ecological Warning, Protection & Restoration for Bohai Sea, Ministry of Natural Resources, Qingdao 266100, China
| | - Yiming Li
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Institute for Advanced, Ocean Study, Ocean University of China, Qingdao 266100, China; College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China
| | - Jinren Lu
- College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China
| | - Mutai Bao
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Institute for Advanced, Ocean Study, Ocean University of China, Qingdao 266100, China; College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China.
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Shuwang X, Zhang G, Li D, Wen Y, Zhang G, Sun J. Spatial and temporal changes in the assembly mechanism and co-occurrence network of the chromophytic phytoplankton communities in coastal ecosystems under anthropogenic influences. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 877:162831. [PMID: 36924961 DOI: 10.1016/j.scitotenv.2023.162831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 02/27/2023] [Accepted: 03/09/2023] [Indexed: 05/06/2023]
Abstract
As a typical semiclosed coastal sea area in China, the ecological environment of Bohai Bay has been significantly disturbed by human activities. As primary producers, the chromophytic phytoplankton are the basis of ecosystems, especially in coastal ecosystems, and changes in the chromophytic phytoplankton community can affect the stability of the entire ecosystem. In this study, we investigated the effects of the human activity-induced spatial and temporal environmental heterogeneity on the community composition, diversity, assembly mechanisms, and co-occurrence networks of chromophytic phytoplankton in Bohai Bay during the wet season and the dry season. The results showed that in both seasons, there was obvious environmental heterogeneity between the nearshore area and the offshore area, and the nearshore areas were more affected by human disturbance. Although higher diversity was supported by the abundance of nutrients in nearshore areas, co-occurrence network analysis revealed that the chromophytic phytoplankton were less closely connected to each other in nearshore areas than in offshore areas due to chemical oxygen demand (COD), eutrophication index (EI), and dissolved inorganic nitrogen (DIN). The nearshore network was less stable than the offshore co-occurrence network in both seasons, which was related to the concentration of dissolved oxygen and COD. Both stochastic and deterministic processes dominated the assembly of the chromophytic phytoplankton communities, with different importance rankings of stochastic and deterministic processes in the nearshore and offshore areas. Drift dominated the assembly of the communities in nearshore areas, while variable selection dominated the assembly of the communities in offshore areas. DIN, EI, and COD, rather than geographic distance, were the main environmental factors affecting the phylogenetic turnover of the chromophytic phytoplankton. Our study showed that environmental heterogeneity caused by human disturbance had a greater impact on the chromophytic phytoplankton communities in Bohai Bay than natural factors such as temperature and salinity.
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Affiliation(s)
- Xinze Shuwang
- Institute for Advanced Marine Research, China University of Geosciences, Guangzhou 511462, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Wuhan), Wuhan 430074, China; College of Fisheries, Ocean University of China, Qingdao 266003, China
| | - Guodong Zhang
- Institute for Advanced Marine Research, China University of Geosciences, Guangzhou 511462, China; Research Centre for Indian Ocean Ecosystem, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Danyang Li
- Institute for Advanced Marine Research, China University of Geosciences, Guangzhou 511462, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Wuhan), Wuhan 430074, China; Research Centre for Indian Ocean Ecosystem, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Yujian Wen
- Institute for Advanced Marine Research, China University of Geosciences, Guangzhou 511462, China; Research Centre for Indian Ocean Ecosystem, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Guicheng Zhang
- Institute for Advanced Marine Research, China University of Geosciences, Guangzhou 511462, China; Research Centre for Indian Ocean Ecosystem, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Jun Sun
- Institute for Advanced Marine Research, China University of Geosciences, Guangzhou 511462, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Wuhan), Wuhan 430074, China; Research Centre for Indian Ocean Ecosystem, Tianjin University of Science and Technology, Tianjin 300457, China.
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