温度对外源性^32P在水、铜绿微囊藻和底泥中迁移的影响

采用同位素示踪法，在实验室模拟研究不同温度下外源性无机磷酸盐在水、铜绿微囊藻(Micro-fystis aeruginoas)和底泥中的迁移过程，外源性³²P加入水中后，首先是一种与温度无关的快速物理化学分配，大量溶解性磷酸盐迅速进入底泥和微囊藻中，随后水中³²P的迁移主要受微囊藻生长状况的影响，温度升高有利于微囊藻的生长，并提高了微囊藻吸磷的速度，微囊藻中最大外源性磷浓度只与水环境中的初始磷浓度有关，25℃时铜绿微囊藻的生长曲线有7d的对数期，没有明显的稳定期就转入衰亡期，在25℃时，当微囊藻超积累P到一定程度后，其对数生长同细胞内含P量无关，随着时间的推移，外源性³²P不断向底泥中迁移，实验末期所有的³²P都转移到底泥中，提高温度使水中溶解性外源性磷的下降速率加快，7d后水中溶解的外源性磷浓度低于0．00716mg·L^-1。

32P in water column, Microcystis aeruginosa and sediments

Effect of temperature on the translocation of exogenous phosphorus in the simulative ecosystem composing of water, Microcystis aeruginosa and sediments was studied with the method of phosphorus isotope tracer. Exogenous 32P was initially distributed rapidly in the ecosystems in a mode of physical chemistry, irrespective of the influence of different temperature. Then, the translocation of 32P was significantly affected by the growth of M. aeruginosa in the ecosystem. Relatively high temperature was favorable to the growth of M. aeruginosa and accelerated the adsorption of exogenous phosphorus. The maximum concentration of exogenous endocellular phosphorus in M. aeruginosa was only related with the initial phosphorus concentration of water environment. The growth curve of M. aeruginosa contained short lag phase, 7-day log phase and decline phase but no obvious stationary phase at 25 degrees C. After certain amounts of exogenous phosphorus were accumulated in M. aeruginosa, its growth was independent of the amounts of endocellular phosphorus at 25 degrees C. The exogenous 32P moved from water and M. aeruginosa to sediment continuously and almost all of them transferred into sediment through the sedimentation of M. aeruginosa at the end of the experiment. The concentration of dissoluble exogenous 32P declined rapidly when water temperature was high and was less than 0.00716 mg.L-1 after 7 days.