滇池现代沉积物中磷的地球化学及其对环境影响

湖泊沉积物中,磷是产生富营养化的重要元素.湖泊中磷元素含量、地球化学行为以及它的复杂矿物学特征,使人们对磷的研究极为重视.滇池湖中总磷超标10.3倍,底泥沉积物中P2O5平均含量0.52%,最高可达1.92%.滇池地处磷矿区,是磷质来源最丰富的湖泊,统计表明,磷含量每年在不断增长.滇池沉积物中磷主要以吸附态、有机态、铁结合态、钙结合态、铝结合态等几种形式存在.这些形态磷在底泥中是不稳定的,它们在环境改变条件下,又将磷释放到水体中.微生物在磷的循环过程中起了重要作用,乳酸菌对不溶性磷酸盐的分解,使湖泊中可溶磷含量增高.聚磷菌对磷元素的富集以及聚磷菌死亡后发生有机磷的矿化作用,是湖泊中水合磷酸盐矿物沉积的重要途径.当湖泊中这种不稳定的水合磷酸盐矿物在条件具备的情况下,经沉积物覆盖成岩作用后,最终形成磷灰石。

Geochemistry and Influence to Environment of Phosphorus in Modern Sediment in Dianchi Lake

Phosphorus is an important element which produces eutrophication in lake sediment. People have paid special attention to the phosphorous research according to its content and geochemical activity as well as complenmineral characteristics in the lake. The total content of phosphorus in Dianchi lake is 10.3 times as high as normal data. The average content of P 2O 5 in bottom mud is 0.52%,and the highest content reaches 1.92%. There are many phosphorus mineral deposits,so the source of phosphorus in the lake is very rich. On the basis of statistics ,the phosphorus content has been increasing every year. The existing forms of phosphorus in Dianchi sediment are mainly in adsorbed form, organic form and combined with Fe,Ca,Al and Sb.These forms of phosphorus in the bottom mud are not stable, easily changing with environment,so phosphorus can be released into the water body again. Microorganisms play an important role in the circuation of phosphorus, lactate bacteria can resolve phosphate and make the content of soluble phosphorus increase in the lake. The enrichment of phosphorus can be due to assemble phosphorus bacteria and,after they die, the mineralization of the organic phosphorus is important way which result in hydrated phosphate deposit in the lake. When conditions are suitable, the unsteady hydrated phosphate is covered by sediment , after mineralization, it will become apatite in the end .