Vertical Changes Of Nutrients In The Sediments Of Urban Lakes In Guangdong

Shallow lakes playing an important role in urban ecological environment, but many shallow lakes are confronted with the process of sever eutrophication. Polluted sediment block the harnessing progress of aquatic environment. It's significant for restoring lake ecological system to strengthen the research of the distribution and chemical forms of and release from sediment. In this paper, we investigated the sediments of thirteen urban lakes in Guangdong with the means of field research, sample analyze and simulation of study in lab. The study on character of sediments and nutrient release is primary. The aim is to reveal the vertical characteristic of sediment and nitrogen and phosphorus release. The study should benefit the precaution of eutrophication of these lakes. The result showed that,1. The distributions of nutrients in lake sediments showed surface enrichment, which suggested that pollution in this area were becoming more serious in recent years. The mean TP contents in sediments ranged from 0.35 mg·g -1 to 4.00 mg·g -1, and the mean TN content ranged from 0.76 mg·g^-1 to 6.75 mg·g^-1, and the LOI ranged from 5% to 10 %..2. The inorganic sedimentary phosphorus consisted mainly of NaOH-P. The concentrations of different phosphorus forms followed the order: NaOH-P content was the highest in the four inorganic phosphorus forms and NH₄Cl-P was the lowest, While the rank order of BD-P and HCl-P content were not similar in different lake sediments. BAP contents in sediments ranged from 0.20 to 2.44 mg·g^-1, accouting for 14.12 %-80.74 % of TP and more than half lakes sediments were above 50 %, which indicated the great potential nutrients release capacity of the sediments.3. The distributions of nutrients in lake sediments of Guangdong Province showed great regional diversities. The nutrient contents in urban areas were higher than that in suburbs. The process of urbanization accelerated the eutrophication level of lakes.4. The nutrients release of lake sediments were summarized through the simulated experiment of sediment cores from Huizhou West Lake, and the results...