The characteristics of nutrients and eutrophication status in Poyang Lake, China

Poyang Lake, the biggest freshwater lake in China, has been observed with accelerated nutrient enrichment over the past two decades. In Nov 2005, Jan 2006 and July 2006, the concentrations of nitrate nitrogen(NO₃^--N), nitrite nitrogen(NO₂^--N), ammonia nitrogen(NH₄^--N), total nitrogen(TN), phosphate phosphor(PO₄^3--P), total phosphor (TP), dissolved oxygen(DO), temperature and other parameters were investigated at 65 stations in the Poyang Lake and its tributaries in order to analyze the characteristics of nutrients and eutrophication status. The results indicated that the dissolved inorganic nitrogen (DIN) mainly came from its tributaries in the Poyang Lake, and NO₃^--N was the main form of DIN in most area. The nitrate nitrogen concentration in Ganjiang River was obviously higher than that of other mainstreams and Poyang Lake. The Poyang Lake is facing eutrophication with high nutrients and the nitrogen and phosphorus is the main nutrient elements. It will appear eutrophication phenomena if the suitable conditions were met.