The Phosphorus Transfer And Refining Of The Yangtze Coastal Wetland

The coastal wetland, as a typical transitional zone between land and ocean, is a multifunctional and complex ecosystem with special ecological values and potential resources. Unfortunately with the development of society and advancement of human beings, it is seriously impacted by human activities, such as wastewater discharge, reclamation. In recent years red tides frequently happen, and the water of estuarine wetland is facing eutrophication. So the studies on "Phosphorus transfer and refining of the Yangtze estuary coastal wetland" would have important academic and practical meanings.In this paper Chongming Dongtan wetland was taken for an example, the phosph Orus removal efficiency and its influencing factors of tidal wetland were investigated. According to the discussions, some suggestions on how to build a coastal artificial we tland were brought forward.The study results showed that pH of Chongming Dongtan wetland sediments is within the range of 7.60～8.00, taking on alkalescent. The granularity compositions of sediments are mainly silts, whose average percentages is 83.64%. The percentages of sands and clays are 6.67% and 9.69% respectively. The TOC of Chongming Dongtan sediments vary in the 0.20～11.00%. The main metallic element is Al₂O₃.TP contents of Chongming Dongtan sediments change appearing from 465.78mg/kg to 824.95 mg/kg. Phosphorus of Chongming Dongtan sediments mainly consists of Ads-P, Ca-P, Fe-P, Obs-P and Org-P, in which Ca-P and Org-P are dominant compositions, moreover the phosphorus of sediments has a distinct spatial distribution characteristics. The distribution of Ca-P is very stable in the sediments of the main and north sections. The average Ads-P compostion is the highest in the surface sediments of the main section and is the lowerest in the surface sediments of the north section. however Fe-P and Org-p compositions are the highest in the surface sediments of the north section, the lowerest in the subsurface sediments of the main section. The phosphorus distributions of sediment are affected by the grain sizes and TOC of sediments.