滇池水体沉积物磷素特征及其对藻类的影响

Characteristics of phosphorus in the sediment of Dianchi Lake and its effects on algae

为揭示在外源磷得到控制的情况下,滇池沉积物磷在适宜条件下释放特征及其对藻类的影响,采用室外模拟方法,研究滇池沉积物与上覆水中的磷素特征,探索沉积物磷释放对藻类的影响。结果表明:上覆水下层水中各形态磷(总磷、可溶性磷、正磷酸盐)含量高于上层水;沉积物中磷素形态以钙结合态磷和有机磷为主,向水体释放贡献最大的是铁铝结合态磷和有机磷;水中正磷酸盐与水中叶绿素a含量呈正相关关系,正磷酸盐含量升高显著加剧水体富营养化;沉积物中可交换态磷含量与水体叶绿素a呈极显著正相关,沉积物磷释放是藻类生长的最主要内源负荷。研究表明,控制水体中的正磷酸盐和沉积物中铁铝结合态磷的浓度以及限制有机磷的转化和矿化是控制藻类的有效措施。

In order to determine the release characteristics of phosphorus in Dianchi Lake, Yunnan, China under suitable conditions and evaluate its effects on algae in the presence of exogenous phosphorus, an outdoor simulation method was used to study the characteristics of phosphorus in the sediment and overlying water of Dianchi Lake and to explore the effects of phosphorus release from sediments on algae.The results showed that the phosphorus content(total phosphorus, dissolved phosphorus, and orthophosphate)in the lower layer of the overlying water was higher than that of the upper layer. Phosphorus was mainly present in the sediment as calcium-bound phosphorus and organic phosphorus. The most important contributions to phosphorus content in water were from iron-aluminum-bound phosphorus and organic phosphorus. There was a positive correlation between orthophosphate and chlorophyll content in water. The increase in orthophosphate content significantly aggravated the eutrophication of water. The exchangeable phosphorus content in the sediment was significantly positively correlated with chlorophyll in water. The release of phosphorus from the sediment was the most important endogenous load for algae growth. Therefore, controlling the concentration of iron-aluminum-bound phosphorus in orthophosphates and in sediment in water bodies, as well as limiting the conversion and mineralization of organic phosphorus, could be an effective control measure.