RESUMO
Dianchi Lake is one of the most three seriously eutrophic lakes in China. In the present study, the phosphorus [P] and nitrogen [N] fractions in 37 surface sediments samples collected in the Dianchi Lake were investigated. The total phophorus [TP] in sediments was divided into two parts: inorganic P [IP] and residual P [Res-P]. The results showed that the total phosphorus content in surface sediments ranged from 1465.27 to 3650.12 mg/kg, IP was the major component of TP and the Ca bound P was the main fraction of IP. The bio-available phosphorus [BAP] in Dianchi Lake was first estimated in this study. BAP ranged from 215.66 to 678.02 mg/kgand the mean concentration was 382.78 +/- 89.77 mg/kgfor all 37 samples. The nitrogen fractions for the whole Dianchi Lake were firstly studied. It was shown that the sediment had been an important N nutrient source of the water, owing to the high content of transferable nitrogen forms in the sediment