Eutrophication control strategies for highly anthropogenic influenced coastal waters

Rapid economic development and urbanization necessitate an understanding of anthropogenic effects on coastal eutrophication. It is a significant challenge for governments to alleviate water degradation and remediate coastal ecosystems. Shenzhen Bay in China, located in a developed and populous area, was selected to analyze the decadal scale influence of anthropogenic activities on eutrophication as well as the effectiveness of governmental remediation strategies. The results showed that the contribution of nutrients from anthropogenic sources accounted for over 80% of the total loads into the bay. Beginning in 1990, increased anthropogenic activities resulted in the loss of environmental capability and resilience, exacerbated eutrophication and water quality degradation. However, the status of eutrophication has been improved since 2005, following the application of intensive management actions implemented in 2000. The practice of eutrophication control suggested that, in view of technical and engineering feasibility, coastal strategies for similar shallow bays should initially reduce phosphorus, followed by nitrogen and eco-remediation to alleviate the serious aquatic situation immediately. The recovery period of eutrophication would be at least five years after governmental actions from Shenzhen Bay's experience. Furthermore, simulated scenarios indicated that eutrophication ranking of Shenzhen Bay could reach and remains medium Moderate, following a 35% reduction in total nitrogen and a 20% reduction in total phosphorus with corresponding eco-remediation.