[Experiment and model simulation of self-purification capacity of nitrogen and phosphorus in Lake Taihu].

A field experiment was carried out in Zhushanhu in September,2011. On the basis of mass balance,nutrients flow in and out of Zhushanhu and their Digestion-absorption law was illustrated through water quantity-water quality observation of bay heart,bay mouth and rivers around Zhushanhu,which provides basic data for the further research on the self-purification capacity of Lake Taihu.The EcoTaihu model was adopted to simulate the nutrients flow and their self-purification capacity of Lake Taihu. The simulated annual self-purification capacity of total nitrogen and total phosphorus of Zhushanhu was 1 911 t and 116 t,respectively,whereas the observed annual self-purification capacity of total nitrogen and total phosphorus of Zhushanhu was 1 979 t and 119 t,respectively. The model was validated by the observation data. The simulated result showed that the self-purification capacity of total nitrogen of Lake Taihu in year 2006,2008 and 2010 was 4. 00 × 104t,4. 27 × 104t and 4. 11 × 104t,respectively,whereas the self-purification capacity of total phosphorus of Lake Taihu in year 2006,2008 and 2010 was 1. 56 × 103t,1. 80 × 103t and 1. 71 × 103t,respectively.