光照对湖泊沉积物磷释放及磷形态变化的影响研究

将采自太湖的沉积物移至实验室内进行磷释放模拟实验.通过对水-沉积物界面在不同照度下的磷释放趋势研究发现,照度与水-沉积物界面的磷释放量有明显的负相关性.而藻类计数的结果表明,照度与底栖藻类生物量存在正相关性.由此可以推断,光照对沉积物磷释放的影响主要表现为受照度控制生长的底栖藻类吸收沉积物中释放的磷,阻挡其进入上覆水中.不同照度下pH变化的研究结果表明,pH的升高趋势随照度的增强而升高,稳定后的水体偏碱性.通过对在不同照度下沉积物中总磷及磷形态变化规律研究发现沉积物中总磷减少量表现为无光＞中照度＞高照度;沉积物中磷出现无机态减少,有机态增加的现象;照度越高,沉积物中NaOH-P(Fe(Al)-P)减少量与HCl-P(Ca-P)减少量的比例越大.

Study on Effects of Light on Phosphorus Release and Phosphorus Form Change in Lake Sediments

The sediments from Taihu Lake were used for laboratory experiments on phosphorus release.Based on the study on phosphorus release under different light intensities at water-sediments interface, it was shown that there was obvious negative correlation between phosphorus release and light intensity at water-sediments interface. Algae counting experiment showed that there was positive correlation between algae and light intensity.This indicated that benthos algae controlled by light took up phosphorus released from sediments,and thus prohibited phosphorus into the overlying water.The pH values increased with light intensity increase,and the water was in alkali after equilibrium. The result of phosphorus forms experiment showed that total phosphorus decreased with light intensity increase:no light>medium light intensity>high light intensity.The content of IP decreased and OP increased in the sediment. The ratio between the decrement of NaOH-P(Fe(Al)-P) and the decrement of HCl-P(Ca-P) increased with the increase of light intensity.