Effect Of Benthic Epipelic Algae On Phosphorus Fractions In Sediment In Taihu Lake

To grasp the mechanism of the effects of benthic epipelic algae on the phosphorus fractions in the sediment in the large shallow eutrophic lake like Taihu,this paper studied the effects of benthic epipelic algae on the phosphorus fractions in the sediment by analyzing the changes of chlorophyll-a ( chl.a ) content, phosphorus fractions such as NaOH-P ( Fe(Al)-P ), HCl-P( Ca-P ), Inorganic phosphorus (IP ),organic phosphorus ( OP ); and studied chl.a and phosphorus fractions in sediment of Lake Taihu. The main results were as follows:(1 ) The chl.a and nutrient contents were positively correlated. The greater of the chl.a, the greater of effects on phosphorus content in the sediment would be. The growth of the algal was inversely related to the NaOH-P content that the NaOH-P content decreased when the conditions were suitable for algal growth. The changing laws of the chl.a coincided basically with IP and changes of the NaOH-P. The difference in changges between HCl-P and OP was not significant.(2 ) The result of phosphorus forms experiment showed that chl.a decreased with light intensity increase: 100% natural illumination > 50% natural illumination >10% natural illumination >1% natural illumination. Influenced by benthic epipelic algae, the NaOH-P in surface of sediments was correlated negatively with light intensity. So IP did. HCl-P in sediments has no obvious correlation with light intensity.(3 ) In lake Taihu, the study found that phosphorus fractions in the surface layer of sediment has correlation with benthic epipelic algae biomass. Moreover, HCl-P and NaOH-P had negative correlative with algae biomass. What is more, total phosphorus and inorganic phosphorus has the most significant correlation with benthic epipelic algae algae. Benthic epipelic algae can influence the distribution of sediment phosphorus in the lake of Taihu, and it has little influence on sediment total nitrogen content.