Overview
Urban lakes are important components of urban ecosystems because of their water storage and regulation functions, and they serve as landscape elements and recreational sites. This study developed a model of phosphorus diagenesis — rarely assessed in lake water quality simulations — to simulate and analyze the dynamic release of phosphorus at the sediment–water interface, and to investigate the response relationship among phosphorus input load, phosphorus flux from sediment, and total phosphorus in lake water.
Model Setup
The diagenesis model was developed to continuously describe phosphate flux at the sediment–water interface, and was tested under different scenarios to examine the response of total phosphorus in the water column to varying input loads.
Key Findings
The results indicate that the model is capable of continuously describing phosphate flux at the sediment–water interface. Under different testing scenarios, the sediment acts as a “buffer” that absorbs or releases phosphate to maintain a balance between the overlying water and sediment, thus providing phosphate for algae growth over a long time even when large external loading is reduced. Using a diagenesis model to treat sediment release may therefore be better than the traditional “assigned-value” method, and this approach will likely be increasingly used in future modelling work.