Abstract:

Based on the measured concentration of total nitrogen (TN) and total phosphorus (TP) in Lake Poyang, in July,2011, firstly we classified the sediment of Lake Poyang into three categories according to the spectral signatures of different sediments on remote sensing images, which are sand, mudflat, and grassland. Then we analyzed the content characteristics of TN and TP in both water and sediment of different bottom sediment types. The results show as follows. (1) It has different TN and TP content in surface waters on different sediment types, representing a pattern of sand > mudflats > grass. TP content in bottom sediment has the same characteristics of TN and TP in surface water, and the characteristic of TN content in sediment is grass > mudflats > sand. (2) Stations on sandy sediment mainly distributed from Raohe River to Duchang, and from north branch of Ganjiag River to Duchang, and in the first section of upstream channels. It may result in high TN and TP content of station on sandy sediment from the high pollutants of nitrogen and phosphorus from Raohe River and Ganjiang River, and landsourced pollutants along the way. Part of the stations on muddy sediment distributed from Xingzi to Hukou, and landsourced pollutants is one reason that the surface water of station on grassy sediments has a relative high TN and TP content. And it has the lowest TN and TP content in surface water of stations on grassy sediments because of the absorption of nitrogen and phosphorous from water by grass in sediments