新食物链生态系统中水流速度对净化效果的影响

利用不同流量的循环水流经新食物链生态系统中的栽培层架,研究水流速度对循环水净化效果,旨在揭示新食物链生态系统节水和减排的本质。试验结果表明,流经各单层红萍的水样中溶解氧（DO）含量的上升幅度为0.76-0.96mg.L^-1,铵态氮（NH4^＋-N）含量的下降幅度为0.94-1.19mg.L^-1,分别是流经单层莴苣的5.07-6.40倍和1.71-2.16倍,说明红萍对提高水体中DO含量和去除NH4^＋-N的效果均明显优于莴苣。当养殖循环水流量控制在50mL.s^-1时,流经1层莴苣和3层红萍组成的单个植物栽培床后,DO含量上升了2.80mg.L^-1,系统增O2总量为504.0mg.h^-1;NH4^＋-N含量下降了3.82mg.L^-1,系统NH4^＋-N去除总量为687.6mg.h^-1。可见,红萍是新食物链生态系统的关键植物,在水质净化中起重要作用。利用红萍等植物改善水产养殖水环境,为解决高密度集约化水产养殖的瓶颈问题提供新途径,真正意义上实现新食物链生态系统中养殖污水零排放。

Effect of Flow Velocity on Decontamination of Aquaculture Circulating Water in New Food Chain Ecological System

In order to reveal the essence of water conservation and emission reduction in New Food Chain ecological shed,different current water was flew through the cultivation shelves for studying the effect of water flow velocity on purification.The results showed that using Azolla to decontaminate,the concentration of dissolved oxygen（DO） in the water increased by 0.76～0.96 mg·L^-1 per layer,the concentration of ammonium nitrogen（NH4^＋-N） decreased by 0.94～1.19mg·L^-1 per layer,was 5.07～6.40 times and 1.71～2.16 times of using lettuce respectively,which indicated that the effect of Azolla on increasing DO and removing NH4^＋-N was much better than lettuce.Controlled the water flow at 50mL·s^-1,after water flew through one layer of lettuce and three layers of Azolla,the concentration of DO increased by 2.80mg·L^-1,the total content of O2 increasing of the system was 504.0mg·h^-1,the concentration of NH＋4-N decreased by 3.82mg·L^-1,the total content of NH4^＋-N removal of the system was 687.6 mg·h^-1.It is obvious that Azolla is the critical plant of New Food Chain ecological shed,which play a important role in water purification.Utilizing Azolla and other plants to decontaminate water body provides new ways for solving the bottlenecks of high-density intensive aquaculture,and realizes zero discharge of sewage in aquaculture in a real sense.