黑藻腐解对水-底泥-黑藻系统中磷迁移转化的影响

EFFECT OF DECOMPOSITION OF HYDRRILLA VERTICILLATA ON PHOSPHORUS TRANSPORTATION AND TRANSFORMATION IN WATER-SEDIMENT-HYDRILLA VERTICILLATA SYSTEM

在步入式模拟实验室内,通过控制温度、光照等措施模拟水-底泥-黑藻系统,设置对照组和30g黑藻组、60g黑藻组自然腐解,检测黑藻衰亡腐解期间黑藻生物量及水、底泥和黑藻中总磷及各形态磷含量的变化,从而探讨磷在该系统内的迁移转化。结果表明:黑藻腐解具有明显的阶段性,实验初期分解速率明显高于实验中后期。黑藻组DO总体变化趋势一致,均先下降再升高,p H值在实验期间整体变化不大,变化区间均为7.4~8.4。对照组与30 g黑藻组中ORP总体呈先上升再下降趋势,60 g黑藻组ORP呈先下降后上升趋势。在整个研究阶段,磷含量上升幅度排序为60g黑藻组>30 g黑藻组>对照组。黑藻的腐解改变了系统中磷元素的循环,在腐解前期抑制底泥中磷的释放,腐解后期促进磷的释放,并对各形态磷的迁移转化有明显影响。

The water-sediment-Hydrilla verticillata system was simulated with several measures such as controlling temperature and light in the walk-in simulation laboratory.The control group and the 30g,60g Hydrilla verticillata group were naturally decomposed,the variation of Hydrilla biomass and total phosphorus and various forms of phosphorus in the water were detected during the decay of Hydrilla verticillata,to discusss the transportation and transformation of phosphorus within the system.The results showed that the decomposition of Hydrilla verticillata had obvious stages,and the decomposition rate in the early stage of the experiment was significantly higher than that in the middle and late stage.During the experiment,the trend of DO change in the Hydrilla verticillata groups was first decreased and then increased with consistency,and the change interval of pH value was between 7.4 and 8.4,with little surges.In the control group and the 30 g Hydrilla verticillata group,the ORP showed a trend of increasing first and then decreasing.The ORP of the 60g kelp group decreased first and then increased.During the whole research period,the phosphorus contents of the groups were in the order of 60 g Hydrilla verticillata>30 g>the control group.The decomposing of Hydrilla verticilla changed the circulation of phosphorus in the system,inhibited the release of phosphorus in the sediment in the early stage of decomposing,promoted the release of phosphorus in the late stage of decomposing,and had a significant effect on the migration and transformation of various forms of phosphorus.