有机磷农药对滇池微囊藻生长和摄磷效应的影响

KINETIC STUDIES ON THE EFFECTS OF ORGANOPHOSPHORUS PESTICIDES ON THE GROWTH OFMICROCYSTIS AERUGINOSA AND THE UPTAKE OF PHOSPHORUS FORMS BY MICROCYSTIS AERUGINOSA IN DIANCHI LAKE

采集滇池水体作为铜绿微囊藻培养基,研究了两种有机磷农药(甲胺磷和辛硫磷)对微囊藻生长和摄磷效应的动力学规律。结果表明,在滇池水体中添加较低浓度的甲胺磷(0.8、1.6、3.2mg/L)和辛硫磷(0.02、0.06、0.1mg/L)均能不同程度地促进微囊藻的生长,且在HGZ培养基中抑制微囊藻生长的浓度在滇池水体中却能促进微囊藻的生长。微囊藻的生长取决于细胞内磷的浓度且对磷的吸收利用存在积累性,在微囊藻生长初期,摄取各形态磷的速率较快;随后微囊藻摄取各形态磷的速率较慢。总溶解磷(TSP)和溶解反应磷(SRP)是微囊藻优先摄取的磷形态,在生长过程中微囊藻利用了大量的溶解有机磷(DOP)作为磷源加速生长。这一特点对于微囊藻成为淡水湖泊富营养化发展过程中的一种重要优势种具有极为重要的作用。

Dianchi Lake is the largest lake in Yunnan Province of China.It is a plateau lake and has been undergoing the process of eutrophication.Phosphorus is the main limited factor for the growth of algae in Dianchi Lake.Water samples collected from Dianchi Lake as culture medium for Microcystis aeruginosa.The present study aims to illustrate the effects of two organophosphorus pesticides（methamidophs and phoxime） on the growth of Microcystis aeruginosa in the lake water.Meanwhile,the kinetic mechanism of uptake of phosphorus forms by Microcystis was also studied.The results indicated that addition of organophosphorus pesticides to lake water at concentration of 0.8,1.6,3.2 mg/L（methamidophs） and 0.02,0.06,0.1 mg/L（phoxime） stimulated the growth of Microcystis.Under certain concentration,methamidophs and phoxime could inhibit the growth of Microcystis in the HGZ medium,but accelerate the growth in the lake water.The growth rate of Microcystis was dependent upon the concentration of intracellular phosphorus,and accumulative consumption of phosphorus by the alga was testified.Each phosphorus form was used by the alga rapidly at initial phase of algal growth and the concentration of phosphorus forms changed very limited in subsequent phase.The total soluble phosphorus（TSP） and soluble reaction phosphorus（SRP） were the preferential phosphorus forms used by Microcystis and as P source,dissolved organic phosphorus（DOP） was also utilized by the alga to accelerate the growth of Microcystis.All above characteristic play an important role in promoting Microcystis bloom.