外源硫酸盐介入下沉积物磷释放、解磷微生物及磷酸酶活性的变化

Effect of external sulfate on phosphorus release, phosphate-solubilizing microorganisms and phosphatase activity in Lake Donghu,Wuhan

人类生产活动导致湖泊水体硫酸盐浓度日益增加,硫酸盐与沉积物中磷之间的关系引起关注.该研究以武汉东湖水和沉积物为研究对象进行实验室模拟,研究为期近一年且温度变化的条件下外源硫酸盐对沉积物释磷及微生物的作用.结果表明,硫酸盐输入使沉积物pH和氧化还原电位(E h)总体呈降低趋势.外源硫酸盐促进了沉积物磷的释放,输入硫酸盐(S500)与对照(CK)之间的上覆水存在显著差异(p<0.01),S500的上覆水中总磷浓度最高值达0.33 mg·L-1,为对照的2倍.湖泊沉积物中有机磷解磷菌的数量高于无机磷解磷菌,上层沉积物解磷菌的数量和沉积物总磷的含量之间呈负相关.S500的沉积物中磷酸二酯酶活性高于磷酸单酯酶活性,且不同分层沉积物磷酸单酯酶活性和磷酸二酯酶活性之间的正相关性达到显著水平.温度升高,磷酸酶的活性逐渐增强,促使沉积物内源磷释放量增加.

Average concentrations of sulphate in lakes keep increasing sharply due to the anthropogenic disturbance. The relationship between sulfate and phosphorus in sediments can not be ignored. In this research, an experiment using the overlying water and sediments from Lake Donghu was performed under indoor conditions for nearly one year to investigate the influence of external sulfate on phosphorus release and microorganisms. The results demonstrated that pH and redox potential （Eh） in the sediments of Lake Donghu decreased in general with the input of sulfate. The release of phosphorus from sediments was aggravated with the input of external sulfate, and there was a significant difference （p〈0.01） for the phosphorus release between samples with sulfate input （S500） and control. The maximum total phosphorus concentration in overlying water of S500 was up to 0.33 mg·L^-1 and twice as much as that of control. The amount of organic phosphorus solubilizing microorganisms was larger than that of inorganic ones in the sediments. There was a negative correction between the amount of phosphate solubilizing microorganisms and the content of TP in the upper sediments. Sulfate input caused higher activity of phosphodiesterase than phosphomonoesterase in the sediments. There was a significant positive correlation between the activity of phosphodiesterase and phosphomonoesterase in the sediments of S500. The phosphatase activity was enhanced with the rise of temperature, leading to more phosphorus released from the sediments into the overlying water.