生态浮岛植物在富营养化养殖水体中去磷途径的初步分析

植物修复富营养化养殖水体过程中磷(P)的去除途径主要包括植物吸收、植物根系吸附、底泥吸附和还原状态下的磷挥发。为了深入探讨植物修复去磷机理,阐明植物修复富营养化养殖水体过程中磷的去向问题,分别以夏秋季(高温)和冬春季(低温)的高效除磷植物大漂和冬牧70组成的生态浮岛为研究对象,通过研究模拟条件下的富营养养殖水体生态修复系统,研究不同温度季节下生态浮岛植物在富营养养殖水体中各去磷途径对水体总磷(TP)去除量的贡献率大小。结果表明:经过20 d处理后,生态浮岛植物大漂和冬牧70对富营养化养殖水体中总磷的去除效率都较高 ,均达50%以上;在生态浮岛植物修复富营养养殖水体过程中最主要的磷去除途径都为植物吸收作用和底泥吸附作用,分别占水体中总磷去除量的23%~58%和27%~51%;其次是植物根系吸附作用,占水体中总磷去除量的13%~28%;贡献率最低的是还原状态下的磷挥发,一般低于1.5%,几乎可忽略不计。

Ways of phosphorus removal from eutrophic aquaculture water by ecological floating culture plants

The ways of P removal from eutrophic aquaculture water in the process of phytoremediation included plant absorption,root system adsorption,sediment adsorption(mainly including flocculation and deposition)and P volatilization(PH₃)under reductive state.In order to futher investigate the mechanism of P removal and clarify the ways of P removal from eutrophic aquaculture water by phytoremediation,we took Pistia stratiotes L.and Secale cereale L.which had higher P removal efficiency as experiment materials respectively in summer-autumn(high-temperature)seasons and winter-spring(low-temperature)seasons.The contribution ratios of these four ways of P removal in the total phosphorus(TP)removal from eutrophic aquaculture water were respectively studied through simulating ideal ecological phytoremediation system.The study results showed that both of the two ecological floating culture plants P.stratiotes L.and S.cereale L.have higher TP removal efficiency from eutrophic cultivated water,which both reach higher than 50%;And the two main ways of P removal by ecological floating culture plants are plant absorption and sediment adsorption whose contribution ratios respectively are 23%-58% and 27%-51% for TP removal;Second is root adsorption whose contribution ratio is 13%-28%;The lowest contribution ratio was observed in the track of P volatilization under reductive state whose contribution ratio is only lower than 1.5%,thus,this contribution in TP removal is very small and could be neglected.The results of this study can be considered as the preliminary research basis for using ³²P isotope tracer method for further careful in depth study of the movement of P in eutrophic aquaculture water.