Annual Cycle and Budgets of Nutrients in the Bohai Sea
渤海氮磷营养盐的循环和收支

High concentrations of dissolved inorganic nitrogen and phosphate contributed much to the environmental problems in the Bohai Sea in the last decade. It is important to understand the cycle and the budget of nutrients for the environmental management. A three-dimensional ecosystem model, coupled with a physical transport model, was adopted in this study. The simulation of the year 1982 was validated by data in 1982/1983. There were depletion from spring to summer and elevation from autumn to winter for nutrients. The higher concentration of phosphate was found at the Bohai Bay and the concentration of phosphate maintained higher level in the whole year. The higher concentration of dissolved inorganic nitrogen located near the Huanghe Estuary. Production and respiration were the most important sink and source of nutrients. The remineralization of the detritus pool can compensate 30 percent of the consumption of nutrient by the production process. The inputs of phosphates and nitrogen from river were P 0.55×103t and N 52.7×103t.