The thermal discharge from coastal nuclear power plants and thermal power plants (CNATPP) not only increases the water temperature, but it also stratifies the seawater. Comprehending the characteristics of stratification that is caused by thermal discharge constitutes the basis for developing a comprehensive understanding of how thermal discharge affects marine organisms. The spatial and temporal characteristics of seawater stratification induced by thermal discharge were analyzed on the basis of measured data while using two study areas with different tidal dynamics as examples. The results showed the following. (1) Thermal discharge influenced the area within 3 km of the outlet. (2) In the East China Sea (which has strong tidal dynamics), the most significant stratification occurred 0.5 km–1.0 km from the outlet; however, in the South China Sea (which has weak tidal dynamics), the degree of stratification decreased with increasing distance from the outlet. (3) In the East China Sea (i.e., strong tidal dynamics), the depth of the thermocline during ebb tide gradually moved upward, while that during flood tide gradually moved downward, and the opposite was observed in the South China Sea (i.e., weak tidal dynamics). Finally, (4) the thermocline that was caused by thermal discharge mostly occurred at water depths above 7 m.

Urban development is a major cause for eco-degradation in many coastal regions. Understanding urbanization dynamics and underlying driving factors is crucial for urban planning and management. Land-use dynamic degree indices and intensity analysis were used to measure land changes occurred in 1990, 2002, 2009, and 2017 in the coastal zone around Quanzhou bay, which is a rapidly urbanized bay in Southeast China. The comprehensive land-use dynamic degree and interval level intensity analysis both revealed that land change was accelerating across the three time intervals in a three-kilometer-wide zone along the coastal line (zone A), while land change was fastest during the second time interval 2002–2009 in a separate terrestrial area within coastal zone (zone B). Driven by urbanization, built-up gains and cropland losses were active for all time intervals in both zones. Mudflat losses were active except in the first time interval in zone A due to the intensive sea reclamation. The gain of mangrove was active while the loss of mangrove is dormant for all three intervals in zone A. Transition level analysis further revealed the similarities and differences in processes within patterns of land changes for both zones. The transition from cropland to built-up was systematically targeted and stationary while the transition from woodland to built-up was systematically avoiding transition in both zones. Built-up tended to target aquaculture for the second and third time intervals in zone A but avoid Aquaculture for all intervals in zone B. Land change in zone A was more significant than that in zone B during the second and third time intervals at three-level intensity. The application of intensity analysis can enhance our understanding of the patterns and processes in land changes and suitable land development plans in the Quanzhou bay area. This type of investigation is useful to provide information for developing sound land use policy to achieve urban sustainability in similar coastal areas.

Background: Coastal wetlands with high biodiversity and productivity provide essential ecosystem services that have a significant positive socio-economic impact. However, coastal reclamation, pollution, and climate change are threatening coastal wetlands. Thus, it is critical to identify priority areas for restoration and improve habitat resilience to adapt to environmental changes. Here, we propose a general analysis framework integrating nature-based solutions (NbS) into habitat restoration to increase coastal resilience to multiple stressors in Sansha Bay, southeast China. Results: The total loss of value in ecosystem services due to reclamation in Sansha Bay was US$162.18 million from 2000 to 2015. The coastal habitats were at medium risk of degradation, with some high-risk areas concentrated in the northwest and along the west coasts, which were prioritized for restoration. Conclusions: Our proposed framework, which integrates hard and soft engineering such as mudflat renovation, mangrove afforestation, and an ecological seawall, can aid in the improvement of coastal resilience. The project cost was US$12.71 million and was estimated to generate US$36.75 million in environmental services. We recommend evaluating and monitoring shoreline changes, environmental factors, and marine biological resources using long-term sampling surveys and remote sensing methods. Our findings can serve as a guide for government decision-making in coastal restoration planning and management.

Heavy metals are extremely harmful materials to marine ecosystems and human health. To determine the anthropogenic contributions and ecological risks in Weitou Bay, China, the spatiotemporal variations in the concentrations of heavy metals in surface sediment were investigated during spring 2008 and 2017. The results indicated that high concentrations of pollutants were generally located near the river mouths and along the coast of industrial areas. Principal component analysis indicated that heavy metal contents were mainly affected by industrial waste drainage, urban development, natural weathering and erosion, and interactions between organic matter and sulfides. The potential ecological risk assessment demonstrated that, in 2008, 82% of the sampling sites were at low risk, while 18% were at moderate risk. The situation had deteriorated slightly by 2017, with 73%, 18%, and 9% of stations in Waytou Bay at low, moderate, and very high risk, respectively. Cd was the most harmful metal, followed by Hg. These two elements accounted for more than 80% of the potential ecological risk index (RI) value. The present work analyzed the source of heavy metals, identified the major pollution elements and high risk areas, and provides guidance for pollution control and ecological restoration in Weitou Bay.