摇蚊幼虫扰动对富营养化湖泊沉积物—水微界面磷释放的影响

Influence of Chironomid Larvae Bioturbation on Phosphorus Concentrations of Micro Scale in Sediment-Water Interface

为探讨摇蚊幼虫扰动对富营养化湖泊沉积物—水微界面磷释放的影响,以大纵湖湖心区域为研究对象,通过室内培养试验,模拟摇蚊幼虫扰动下沉积物中磷的释放情况。即利用微电极系统和高分辨率的渗析平衡技术(HR-Peeper),获取摇蚊幼虫扰动沉积物中的溶解氧(DO)和pH值,并同步获取间隙水中的溶解态反应性磷(SRP)和溶解态二价铁(Fe2+),分辨率分别为μm、mm级。结果表明,摇蚊幼虫扰动增加了沉积物中DO的渗透深度及pH值,降低了间隙水中60.7%的SRP及42.1%的溶解态Fe2+的浓度,增加了沉积物中铁结合态磷(Fe-P)的浓度,其他结合态的磷(TP、IP、OP、AP)无显著变化。说明摇蚊幼虫扰动沉积物间隙水中的SRP与Fe2+显著相关,因此摇蚊幼虫扰动沉积物中SRP的释放主要受Fe2+的氧化还原所控制。

To examine the impact of bioturbation of chironomid larvae on phosphorus exchange across sediment-water interface in eutrophic lakes,the laboratory incubation experiments was carried out with sediments and lake water from the central area of Lake Dazonghu.Microelectrode system and high-resolution dialysis（HR-Peeper）techniques were used to obtain DO,pH,SRP and Fe2＋,which are at aμm and mm resolution respectively.The results show that the larvae bioturbation increased concentrations of DO and pH,decreased 60.7% of SRP and 42.1% of Fe2＋in pore water and was not able to change the distribution of the forms of phosphorus（TP,IP,OP,AP）except Fe bound P（Fe-P）.In addition,the high correlation of soluble P with soluble Fe was found in the experiment.Through all of these results,it can be concluded that the release of soluble P is mainly controlled by Fe2＋.