Sediment Characteristics of Erhai Lake and Its Impact on the Overlying Water

In order to gain an in-depth understanding of the sediment particle size characteristics and the distribution of carbon,nitrogen and phosphorus in Erhai Lake, and to assess the impact of the release of nitrogen and phosphorus nutrients from the sediments on the water quality of Erhai Lake, the sediment samples of 19 points in the lake and sediments were analyzed in December 2020. The results of the resuspension simulation experiment showed that the thickness of the sediments has significant spatial differences, and the near-shore area to the west had a larger particle size and the rest areas had smaller particle sizes; the organic matter content of the sediments was between 12.3～26.1g/kg, and the average value was 23.24±3.49g/kg, the areas with high organic matter content were mainly concentrated in the lake platform and the southeast lake area; the total nitrogen content in the sediments was between 2190～8340mg/kg, the average value was 5172±982.6mg/kg, and the nitrogen was mainly distributed in the areas where human activities were concentrated, the areas with high nitrogen values were in the southern lake area, generally in the south>central>north. The total phosphorus content in the Lake sediments was between 607～1240 mg/kg, with an average value of 904±189.8 mg/kg, and the high phosphorus value area in the deep water area of the lake center platform, the order was central>south>north; the release of endogenous pollution load of nitrogen and phosphorus nutrients in the sediments of Erhai Lake had little effect on the water quality of the whole lake.