[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 x 10(4) t, 4. 27 x 10(4) t and 4. 11 x 10(4) t, respectively, whereas the self-purification capacity of total phosphorus of Lake Taihu in year 2006, 2008 and 2010 was 1.56 x 10(3) t, 1.80 x 10(3) t and 1.71 x 10(3) t, respectively.