Seasonal Self-Purification Process of Nutrients Entering Coastal Water from Land-Based Sources in Tieshan Bay, China: Insights from Incubation Experiments
Nutrients function as essential biological substrates for coastal phytoplankton growth and serve as pivotal indicators in marine environmental monitoring. The intensification of land-based nutrient sources inputs has exacerbated eutrophication in Chinese coastal water, while mechanistic understandin...
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MDPI AG
2025-06-01
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| Series: | Journal of Marine Science and Engineering |
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| Online Access: | https://www.mdpi.com/2077-1312/13/6/1133 |
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| author | Fang Xu Peng Zhang Yingxian He Huizi Long Jibiao Zhang Dongliang Lu Chaoxing Ren |
| author_facet | Fang Xu Peng Zhang Yingxian He Huizi Long Jibiao Zhang Dongliang Lu Chaoxing Ren |
| author_sort | Fang Xu |
| collection | DOAJ |
| description | Nutrients function as essential biological substrates for coastal phytoplankton growth and serve as pivotal indicators in marine environmental monitoring. The intensification of land-based nutrient sources inputs has exacerbated eutrophication in Chinese coastal water, while mechanistic understanding of differential self-purification processes among distinct land-based source nutrients (river source, domestic source, aquaculture source, and industrial source) remains limited, constraining accurate assessment of bay’s self-purification capacity. This study conducted incubation experiments in Tieshan Bay (TSB) during Summer (June 2023) and winter (January 2024), systematically analyzing the self-purification process of nutrients and associated environmental drivers. Distinct source-specific patterns emerged: river inputs exhibited maximal dissolved inorganic nitrogen (DIN) 1.390 ± 0.74 mg/L, whereas industrial discharges showed peak dissolved inorganic phosphorus (DIP) 4.88 ± 1.45 mg/L. Chlorophyll a (Chl-<i>a</i>) concentrations varied markedly across sources, ranging from 34.97 ± 23.37 μg/L (domestic source) to 86.63 ± 77.08 μg/L (river source). First-order kinetics demonstrated significant source differentiation (<i>p</i> < 0.05). River-derived DIN exhibited the highest attenuation coefficient (−0.3244 ± 0.17 d<sup>−1</sup>), contrasting with industrial-sourced DIP showing maximum depletion (−0.4332 ± 0.20 d<sup>−1</sup>). Correlation analysis indicated that summer was significantly associated with the impacts of three key control factors pH, dissolved oxygen, and turbidity on nutrient dynamics (<i>p</i> < 0.05), whereas winter exhibited a stronger dependence on salinity. These parameters collectively may modulate microbial degradation pathways and particulate matter adsorption capacities. These findings establish quantitative thresholds for coastal nutrient buffering mechanisms, highlighting the necessity for source-specific eutrophication mitigation frameworks. The differential self-purification efficiencies underscore the importance of calibrating pollution control strategies according to both anthropogenic discharge characteristics and regional hydrochemical resilience, which is of key importance for ensuring the traceability and control of land-based sources of pollution into the sea and the scientific utilization of the self-purification capacity of the bay water body. |
| format | Article |
| id | doaj-art-5371bd91635540e3b7e9fbc884de960e |
| institution | DOAJ |
| issn | 2077-1312 |
| language | English |
| publishDate | 2025-06-01 |
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| series | Journal of Marine Science and Engineering |
| spelling | doaj-art-5371bd91635540e3b7e9fbc884de960e2025-08-20T03:16:32ZengMDPI AGJournal of Marine Science and Engineering2077-13122025-06-01136113310.3390/jmse13061133Seasonal Self-Purification Process of Nutrients Entering Coastal Water from Land-Based Sources in Tieshan Bay, China: Insights from Incubation ExperimentsFang Xu0Peng Zhang1Yingxian He2Huizi Long3Jibiao Zhang4Dongliang Lu5Chaoxing Ren6College of Chemistry and Environment, Guangdong Ocean University, Zhanjiang 524088, ChinaCollege of Chemistry and Environment, Guangdong Ocean University, Zhanjiang 524088, ChinaCollege of Chemistry and Environment, Guangdong Ocean University, Zhanjiang 524088, ChinaCollege of Chemistry and Environment, Guangdong Ocean University, Zhanjiang 524088, ChinaCollege of Chemistry and Environment, Guangdong Ocean University, Zhanjiang 524088, ChinaGuangxi Key Laboratory of Marine Environmental Change and Disaster in Beibu Gulf, Beibu Gulf University, Qinzhou 535011, ChinaMarine Environmental Monitoring Center of Guangxi, Beihai 536000, ChinaNutrients function as essential biological substrates for coastal phytoplankton growth and serve as pivotal indicators in marine environmental monitoring. The intensification of land-based nutrient sources inputs has exacerbated eutrophication in Chinese coastal water, while mechanistic understanding of differential self-purification processes among distinct land-based source nutrients (river source, domestic source, aquaculture source, and industrial source) remains limited, constraining accurate assessment of bay’s self-purification capacity. This study conducted incubation experiments in Tieshan Bay (TSB) during Summer (June 2023) and winter (January 2024), systematically analyzing the self-purification process of nutrients and associated environmental drivers. Distinct source-specific patterns emerged: river inputs exhibited maximal dissolved inorganic nitrogen (DIN) 1.390 ± 0.74 mg/L, whereas industrial discharges showed peak dissolved inorganic phosphorus (DIP) 4.88 ± 1.45 mg/L. Chlorophyll a (Chl-<i>a</i>) concentrations varied markedly across sources, ranging from 34.97 ± 23.37 μg/L (domestic source) to 86.63 ± 77.08 μg/L (river source). First-order kinetics demonstrated significant source differentiation (<i>p</i> < 0.05). River-derived DIN exhibited the highest attenuation coefficient (−0.3244 ± 0.17 d<sup>−1</sup>), contrasting with industrial-sourced DIP showing maximum depletion (−0.4332 ± 0.20 d<sup>−1</sup>). Correlation analysis indicated that summer was significantly associated with the impacts of three key control factors pH, dissolved oxygen, and turbidity on nutrient dynamics (<i>p</i> < 0.05), whereas winter exhibited a stronger dependence on salinity. These parameters collectively may modulate microbial degradation pathways and particulate matter adsorption capacities. These findings establish quantitative thresholds for coastal nutrient buffering mechanisms, highlighting the necessity for source-specific eutrophication mitigation frameworks. The differential self-purification efficiencies underscore the importance of calibrating pollution control strategies according to both anthropogenic discharge characteristics and regional hydrochemical resilience, which is of key importance for ensuring the traceability and control of land-based sources of pollution into the sea and the scientific utilization of the self-purification capacity of the bay water body.https://www.mdpi.com/2077-1312/13/6/1133land-based sourcesself-purification processchl-<i>a</i>key control factors |
| spellingShingle | Fang Xu Peng Zhang Yingxian He Huizi Long Jibiao Zhang Dongliang Lu Chaoxing Ren Seasonal Self-Purification Process of Nutrients Entering Coastal Water from Land-Based Sources in Tieshan Bay, China: Insights from Incubation Experiments Journal of Marine Science and Engineering land-based sources self-purification process chl-<i>a</i> key control factors |
| title | Seasonal Self-Purification Process of Nutrients Entering Coastal Water from Land-Based Sources in Tieshan Bay, China: Insights from Incubation Experiments |
| title_full | Seasonal Self-Purification Process of Nutrients Entering Coastal Water from Land-Based Sources in Tieshan Bay, China: Insights from Incubation Experiments |
| title_fullStr | Seasonal Self-Purification Process of Nutrients Entering Coastal Water from Land-Based Sources in Tieshan Bay, China: Insights from Incubation Experiments |
| title_full_unstemmed | Seasonal Self-Purification Process of Nutrients Entering Coastal Water from Land-Based Sources in Tieshan Bay, China: Insights from Incubation Experiments |
| title_short | Seasonal Self-Purification Process of Nutrients Entering Coastal Water from Land-Based Sources in Tieshan Bay, China: Insights from Incubation Experiments |
| title_sort | seasonal self purification process of nutrients entering coastal water from land based sources in tieshan bay china insights from incubation experiments |
| topic | land-based sources self-purification process chl-<i>a</i> key control factors |
| url | https://www.mdpi.com/2077-1312/13/6/1133 |
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