Nutrient Variation Characteristics of Luanhekou - Beidaihe Ecological Monitoring Marine Area in August

Data collected from 24 marine monitoring stations in Luanhekou-Beidaihe ecological monitoring marine area from 1999 to 2014 reveal a substantial change in the nutrient of this region. The content of nitrogenous nutrients has increased, but phosphate and silicate have decreased. The average N:P ratios have increased from 4.951 in 1999 to 47.188 in 2014;while the Si:N ratios have decreased. The nutrient structure has substantially changed over a period of 16 years. Before 2004, phosphate was relative surplus but inorganic nitrogen was relative lack, while relative surplus of inorganic nitrogen and relative lack of phosphate after 2004. The water quality changed from low nitrogen and high phosphorus (before 2004) to high nitrogen and low phosphorus (after 2004).This finding shows that the nutrient structure may be related to anthropogenic influence.