磷在“沉积物-自然生物膜-上覆水”三相体系中的迁移转化

Migration and transformation of phosphorus among the three-phase system “sedimentsperiphyton biofilm-overlying water”

地表水体中沉积物表面通常会附着一层自然生物膜,对上覆水-沉积物界面化学物质的迁移转化有着重要的影响.以往研究往往会忽略这一生物层面,因而,开展磷在"沉积物-自然生物膜-上覆水"三相界面之间的迁移转化研究具有重要的实际意义.以软性填料表面形成的自然生物膜模拟沉积物表层以及悬浮颗粒物表层的自然生物膜,开展磷在沉积物-自然生物膜-上覆水之间的迁移转化过程研究.结果表明:有无曝气情况下,自然生物膜界面的存在均能够显著降低上覆水中总磷、溶解态总磷、溶解态无机磷的含量,明显抑制沉积物中可交换态磷向上覆水释放.研究证明自然生物膜在水体磷的迁移转化中起着不可忽视的作用,在研究沉积物-上覆水界面之间磷的迁移转化行为时,要充分考虑自然生物膜界面的存在.

It is well known that periphyton biofilm is a kind of microaggregates that ubiquitously distributed in natural aquatic bodies, usually attaching on the sediment surfaces as well as the surfaces of suspended materials in waters. Therefore, it is more practical and meaningful to study the migration and transformation of phosphorus among “sediments-periphyton biofilm-overlaying water” system rather than the commonly sediments-overlaying water system. In this study, the periphyton biofilms used in experiments were collected from a kind of artificial substrate that designed special for the fast enrichment of periphyton, and then the migration and transformation of phosphorus among “sediments-periphyton biofilm-overlaying water” system was investigated. Results showed that the presence of periphyton biofilm interface could significantly decrease the content of total phosphorus, dissolved total phosphorus, dissolved inorganic phosphorus in overlying water under both situations of aeration and nonaeration, and obviously reduce the release of exchangeable phosphorus from sediments to overlying water. This study shows that it should take the periphyton biofilm interface into accounts when studying the phosphorus behaviors between sediments and overlying water.