河蚬或藻存在下组合扰动对内源磷迁移的影响

为阐明河蚬(Corbicula fluminea)或铜绿微囊藻(Microcystis aeruginosa)存在下,物理和摇蚊幼虫组合扰动对内源磷再生和迁移转化的影响,以太湖梅梁湾上覆水和沉积物为研究对象,分析了上覆水、间隙水、沉积物中不同形态磷的变化规律.结果表明,与摇蚊幼虫扰动和组合扰动相比,河蚬或藻类的出现都会使得上覆水中不同形态磷(总磷、溶解性总磷、溶解性磷酸盐、颗粒态磷)显著增加.河蚬或藻类均导致间隙水DIP明显降低,并致使DIP峰值区域向更深处迁移(3~4cm变为4~5cm),而对照试验则相反.与对照试验相比,河蚬或藻存在下组合扰动均导致0~4cm沉积物NH₄Cl-P含量及其占总磷百分比降低,Fe/Al-P含量及其占总磷百分比增加,并且河蚬或藻对NH₄Cl-P降低和Fe/Al-P增加的影响基本一致.在多种扰动因素存下,摇蚊幼虫对上覆水中DTP和DIP贡献最大,后者可能源于摇蚊幼虫显著降低了间隙水中DIP含量及沉积物中NH₄Cl-P含量.这暗示了在组合扰动基础上叠加河蚬或者藻类,均进一步促进了内源磷再生和迁移.

Impacts of Corbicula fluminea or algae under combined disturbance on internal phosphorus migration

It was to clarify the effect of Corbicula fluminea or algae under physical and Chironomus plumosus combined disturbance on regeneration and transformation of internal phosphorus(P), using the sediment and overlying water from Meiliang Bay, Tai Lake. The variation of P forms in the overlying water, pore water and sediments was analyzed. The results showed that the concentration of Total P(TP), Dissolved total P(DTP), Dissolved inorganic P(DIP), Particulate P(PP) in the overlying water under combined disturbance with the Corbicula fluminea or algae were obviously higher, compared with that under combined disturbance, and they could result in the decrease marked for DIP in the pore water. In addition, the peak area of DIP migrated deep(from 3~4 cm to 4~5 cm under 0 cm) dued to Corbicula fluminea or algae, but the control was not. The content of NH₄Cl-P and the percentage of Fe/Al-P to Total P in the sediment(0~4cm) decreased and the Fe/Al-P increased due to Corbicula fluminea or algae, and the effect of Corbicula fluminea or algae on the NH₄Cl-P decreased and Fe/Al-P increased was the same nearly. Under different disturbance factors, the contribution of Chironomus plumosus on the DTP and DIP in the overlying water was big. One explanation was it reduced the DIP in the pore water and the NH₄Cl-P in the sediment. It was suggested that Corbicula fluminea or algae under combined disturbance could improve the internal P release and migration.