物理和摇蚊幼虫组合扰动对内源磷再生和形态转化的协同作用

为探讨物理和摇蚊幼虫组合扰动对内源磷再生和形态转化的协同作用,选取了苏州某富营养化河道为研究对象.利用室内静态培养试验和Rhizon间隙水采样技术,着重对比了单纯的摇蚊幼虫扰动和组合扰动下,上覆水、间隙水、沉积物中磷形态数量分布的变化规律.结果表明,组合扰动下,上覆水中不同形态磷含量(TP、PP、DTP、DIP)均处于较高水平,明显高于摇蚊幼虫扰动.这可归因于微生物活性的显著增加.与摇蚊幼虫扰动相比,组合扰动下,间隙水中DIP和Fe2+浓度的降低幅度和降低范围明显更大.这主要是由于物理扰动和底栖生物扰动产生的叠加效应,导致溶解氧渗透深度增加.另外,0~2 cm沉积物中,NH4Cl-P含量明显降低,Fe/Al-P明显增加,并且,NH4Cl-P和Fe/Al-P的变化幅度均在组合扰动下最大.这暗示了物理扰动和底栖生物扰动对磷再生和迁移产生的叠加效应.

Synergistic Effect of Physical and Chironomus plumosus Combined Disturbance on Regeneration and Transformation of Internal Phosphorus

To explain the synergistic effect of physical and Chironomus plumosus combined disturbance on the regeneration and transformation of internal phosphorus, laboratory static incubation experiments were carried out with the sediments and overlying water from a eutrophic river in Suzhou. Rhizon samplers were used to acquire the pore water. In the experiment, we compared the variation of different phosphorus forms in the overlying water, the pore water and sediments under the Chironomus plumosus disturbance and the combined disturbance. The results indicated that the amount of different forms of phosphorus (TP, PP, DTP, DIP) in the overlying water under combined disturbance was higher than that under Chironomus plumosus combination disturbance. It was attributed to the significant increase of the microbial activity in the sediments. Compared with Chironomus plumosus disturbance, the amount of DIP and ferrous decreased with the greater magnitude and range. It was attributed to the superposition effect of the physical and benthos disturbance on the penetration depth of the dissolved oxygen. In addition, the amount of NH₄Cl-P decreased remarkably in the 0-2 cm sediment while Fe/Al-P increased obviously. Furthermore, the variation magnitude of NH₄Cl-P and Fe/Al-P was higher under combined disturbance than that under Chironomus plumosus disturbance, which suggested the superposition effect of the physical and benthos disturbance on the regeneration and migration of phosphorus.