Study On The Characteristics Of Organic Phosphorus Fractions In Lake Sediments

As the nutrient ponds of lake, sediments can reflect the value of lake pollution, the evolution of ecological environment and the informations about human activities as well,This research prepared3sediment cores form4different types of lakes, analysised their TP、TN、OM、heavymetals and the characteristics of organic phosphorus, discussed the evolution of nutrients、OM、heavy metal and characteristics of organic phosphorus, the results as belows:Lake Erhai、Taih、Yanghe Reservoir and lake Poyang have experienced a evolution process of poor nutrient to eutrophication, the order of the present eutrophication of these three lakes are:Yanghe Reservoir> Lake Taihu> Lake Erhai> Lake Poyang.The first eutrophication times are:the early80’s、80’s and90’s and90’s respectively.The time of which the lake transformed into eutrophication are:In the late90’s、80’s、in the middle of90’s and late90’s respectively.With the change of river-lake relation, speeded up the transformation of Poyang Lake from "Lake morphology" to "River morphology". The ecolocial risks and the heavy metals accumulated in the trail of "Five Rivers" and "Hukou"may move further into the lake,and the risk of great pollution would spread out to North Lake.The different types of lakes also has the differences of the contant of organic phosphorus fractions, Organic phosphorus fractions changed between1～204mg·kg-1of lake Erhai,The other content of organic phosphorus was relatively stable while the Res-NRP is widely changed between7-147mg.kg"1, Organic phosphorus fractions changed between7-147mg.kg-1of lake Taihu,8.7-285.4mg.kg-1of Yanghe Reservoir and4.94-320.49mg.kg-1of lake Poyang. The transformation happens in every fractions of organic phosphorus, and the transformation between "LOP" and "MLOP" are the most active fractions, the change of "NOP" contains stabe to some extent. As an Important carrier, OM could make the transformation of these3fractions faster or Mineralizated. Fe、Al、Ca are also joined into the circle of organic phosphorus fractions.