Space Distribution Characteristics and Diversity Analysis of Phosphorus from Overlying Water and Surface Sediments in Taihu Lake
太湖水体及表层沉积物磷空间分布特征及差异性分析

The physi-chemical indexes in the overlying water and surface sediments of Taihu Lake,an eutrophic shallow lake,were determined.Then, the isopleth maps of spatial distribution of each parameter were illustrated.The results show that the concentrations of SRP,TP and TN in the overlying water and TOC,TN and TP as well as phosphorus fractions in surface sediments exhibit distinct diversity in spatially.The lowest values of TP and TN were 0.05,0.88 mg·L-1,respectively.The concentrations of Fe-P ranged from 29.13 to 258.31 mg·kg-1.Besides,the northwest lake regions,high-load Ca-P was surveyed in the South Taihu Lake and East Taihu Lake with the highest value of 357.68 mg·kg-1.The highest concentration of OP,371.91 mg·kg-1,was detected in the northwest region of the lake.IP takes up a greater proportion of TP than OP, and the highest value is approximately 50% higher than the lowest value.Fe-P has higher percentage in IP compared with Ca-P.Significant correlation between Fe-P,SRP and TP showed that Fe-P was the important phosphorus source of the overlying water(R: 0.49,0.64).Furthermore,high Correlation coefficients between TOC,TOC,C/N,TN,TP and phosphorus fractions suggest that higher concentration of organics was favor to the accumulation and burial of nutrients.The high-load contaminants exist principally in the Zhushan Bay,Wulihu Lake, Meiliang Bay and the northwest region of Taihu Lake.Significant heterogeneity of nutrients distribution in space of Taihu Lake connects with direct action of emission load of sewage.Simultaneously,different biogeochemical behaviors of each parameter play an important role.