Investigation of Eutrophic Elements Distribution and Their Correlation in Qinhai Lake Surface Sediments

Based on the analysis of sediment samples taken from 11 spots at the surface sedimentary layer of Qinghai Lake, the contents of total phosphorus(TP), total nitrogen(TN), no-apatite inorganic phosphorus(NAIP) and total organic carbon(TOC) were detected while the eutrophic component distribution and relevant correlation were investigated. The result indicated that TP contents were ranged from 0.36 to 0.71 g·kg-1 with the mean value of 0.59 g·kg-1, and the coefficient of variation 15.42% when the average content of TN was 1.74 g·kg-1 with the variation coefficient 43.02%, but 18.60 g·kg-1 for TOC content with an variation coefficient 46.61%. The significant linear relationships(P0.01) among TN, TP and TOC were determined, respectively. It was found that the S-shaped curve relationships between NAIP and TN, TP and TOC were apparently formed at the level of 0.05. The study showed that the effects of depth of overlying water and disturbance extent were the key factors to impact the contents of TP, TN and TOC in Qinghai Lake. Additionally, the effects of outer source inputs resulted by river recharges, tourist activities and dismission also had a certain influence on distribution of NAIP in Qinghai Lake.