Abstract:
The spatial-temporal distribution characteristics of nutrients, influencing factors and nutrient limitation in Shanwei coastal area of Honghai bay were analyzed, and the eutrophication risk was evaluated combined with the potential eutrophication assessment model, based on thirty-two cruises at three stations carried out during 2016-2018. The results showed that DIN in Shanwei coastal area met the second and third class seawater quality standard, and PO
4-P met the first class of seawater quality standard, which satisfied the requirements of marine functional zoning. The spatial distribution characteristics of nutrients showed that the closer it was to Shanwei city, the higher the nutrient concentration was; the interannual variation was that the average concentration of nutrients in 2016 is higher than that in 2017 and 2018; the seasonal variation was complex, there were certain differences in different years for different nutrients. Correlation analysis showed that the temporal-spatial distribution characteristics of nutrients were mainly affected by precipitation, salinity, pH, chlorophyll
a, suspended particulate matter and other environmental factors. The nutrient structure analysis showed that there was phosphorus limitation in Shanwei coastal area of Honghai bay. Although the eutrophication ratio was relatively low, it suffered a high potential risk of eutrophication. Pinqing lake was the high risk area, and the high occurrence period was winter and spring.