扰动对东平湖表层沉积物中氮磷释放的影响

采集东平湖表层沉积物,探讨了扰动对湖泊沉积物中营养盐释放的影响。结果表明,扰动导致的沉积物再悬浮并不会明显改变上覆水的酸碱环境,但是会促进易溶性阳离子的释放。扰动强度为25和50r/min时,沉积物中TN的累积释放量和释放速率均相近,没有明显的差异。但是,当扰动强度增大到100r/min时,与静态释放(即扰动强度为0r/min)相比,沉积物中TN的累积释放量和释放速率分别增加了5.02mg/kg和73.5%;与静态释放(即扰动强度为0r/min)相比,扰动强度为25r/min、50r/min和100r/min时,TP的累积释放量分别增加了0.185、0.263和0.320mg/kg,释放速率也比静态条件下明显增大,分别比静态条件增加了36.2%、41.7%和127.6%。TN和TP的释放量和释放速率均随着扰动强度的增大而呈显著增加的趋势,这表明扰动对沉积物中的TN和TP的释放均具有较大的影响。

Impacts of Disturbance on Release of Total Nitrogen and Total Phosphorus from Surficial Sediments of Dongping Lake

Surficial sediment samples were collected from Dongping Lake to investigate the impacts of disturbance on release of nutrients elements from surficial sediments.Results showed that no significant impacts could be found for the disturbance on pH of lake water,while the soluble cations increased obviously under the disturbance.There is no significant difference could be found for disturbance intensity of 25 and 50rpm on the accumulative releasing contents and releasing velocity of total nitrogen.Under the disturbance intensity of 100rpm,the accumulative releasing contents and releasing velocity of total nitrogen increased by 5.02mg/kg and 73.5% respectively compared with those of under the static state.Under the disturbance intensity of 25rpm,50rpm and 100rpm,the accumulative releasing contents of total phosphorus increased by 0.185,0.263 and 0.320mg/kg compared to the static state.Releasing velocity of total phosphorus increased by 36.2%,41.7% and 127.6% compared to the static state,which indicated that the disturbance would enhance significantly the release of TN and TP from surficial sediments of lakes.