Modeling the interaction of light and nutrients as factors driving lake eutrophication

Abstract

Eutrophication is a major problem in the field of water environments at present, and its main driving factors are light and nutrients. In this paper, the process of eutrophication in small artificial lake is studied, according to the principle of water optics and conservation of mass, the light and the nitrogen and phosphorus in water nutrients were selected as influencing factors, and 16 different scenarios of light-nutrients interaction conditions were designed by orthogonal experiment. Then water eutrophication model was used to analyze the process of eutrophication under different light-nutrient scenarios. According to the comparison of simulation results, if the concentration of nutrients is increased under low light conditions, the growth of algae will be inhibited; And if the light condition is set to a fixed value, the simulation results under different nitrogen and phosphorus concentrations in the water show that the effect of phosphorus on algae growth is greater than that of nitrogen; In addition, comparing the growth of algae under different light and phosphorus scenarios, it can be seen that the light-driven effect is more significant than that of phosphorus. By simulating all the design scenarios and analyzing the results, it can be found that the algae growth rate reaches a maximum when the light intensity and the nitrogen and phosphorus concentration increase to a certain range; while continuing to increase the light and nutrient concentration exceeds a certain threshold range, the rate of algae growth will be inhibited.