Research on Ecosystem Model of Xian Yanming Lake

Ying Wang

Tuesday 30 june 2015

11:15 - 11:30h at Amazon (level 1)

Themes: (T) Hydro-environment, (ST) Impacts of pollutants on the water environment

Parallel session: 5G. Environment – Ecosystem

Yanming Lake located in Chanba Ecological District of Xi'an, is formed by 5 artificial lakes; Yanming Lake was constructed for improvement of ecological environment in east areas of Xi'an. Recently, the nitrogen and phosphorus of the lake are increase and the submerged plants (Myriophyllum) are growing widely. The excessive growth of Myriophyllum forms the canopy in water surface and has covered almost 70% of waters areas of the lake. With the problem of submerged plants_Myriophyllum_growth largely influencing natural landscape in Xi'an Yanming Lake, the paper carries out the simulation and prediction of the influences on the concentrations of Chla, TP and TN when the hydrophyte’s biomass is decreasing. Based on the Lotka-Volterra model and the Vollenweider model, the Ecosystem model of Xi'an Yanming Lake was established and used to describe the interactions and relations among the water plants, the algae, the total phosphorus and the total nitrogen in the lake water. The four state variables are respectively water plant biomass, chlorophyll concentration, total phosphorus concentration and total nitrogen concentration.The aquatic plants, floating algae relations with dynamic change and interaction of nutrients in the lake has been verified with the field data, the result shows that the calculation value can fit the actual value well.