Peculiarities of Distribution of Nutrients in the Northern Dvina Mouth Area According to Long-Term Monitoring

Changes in the concentrations of inorganic forms of biogenic elements in the mouth area of the Northern Dvina River are analyzed based on averaged data of long-term observations (2013-2023). The seasonal dynamics of phosphate phosphorus and inorganic nitrogen was similar; their maximum concentrations were observed in winter. Nitrate nitrogen, whose concentration was maximal in winter, became a predominant form of inorganic nitrogen in 2013-2023.