三峡水库香溪河库湾拟多甲藻(Peridiniopsis)水华对环境中磷的响应机制

于2015年春季拟多甲藻水华暴发期在香溪河支流高岚河、南阳河与干流设置9个采样点,探讨浮游植物种群与水体总磷浓度等环境因子的相关性;同时,分离纯化拟多甲藻后,设置5个不同磷浓度(0、0.005、0.020、0.100、0.600 mg/L)对其进行实验室培养,分别测定其比生长速率;在对数生长期,检测不同磷浓度培养下的藻细胞的快速光曲线及其参数;检测不同磷浓度培养下的藻细胞对外源无机碳的吸收效率及其参数.结果表明,水体中总磷浓度越高的河段,拟多甲藻细胞密度越高;培养基中磷浓度越高,拟多甲藻的比生长速率越大,光合效率越高,其对外源无机碳的吸收能力越强.这些结果表明高磷的水环境可能是促使拟多甲藻形成水华的关键因素之一.

Response mechanism of Peridiniopsis bloom to phosphorus in Xiangxi River Bay of Three Gorges Reservoir

This study attempts to explore the physiological responses of Peridiniopsis bloom to phosphorus concentrations in Xiangxi River Bay of Three Gorges Reservoir.The population dynamics of phytoplankton and some environmental factors of waterbody were investigated on 9 sampling sites in the Xiangxi River Bay during water bloom period in spring of 2015.A strain of Peridiniopsis was isolated and purified from Xiangxi River.Specific growth rates of Peridiniopsis were measured at 5 different concentrations (0,0.005,0.020,0.100 and 0.600 mg/L) of phosphorus culture medium.Rapid light curves,photosynthetic oxygen evolution vs.in-organic carbon concentration curves and their parameters were examined at logarithmic growth phase.Results show that the high cell density of Peridiniopsis may indicate a high total phosphorus concentration.The conditions of high phosphorus could enhance photo-synthetic efficiency of Peridiniopsis,stimulate its growth,and increase its affinity for inorganic carbon.Therefore,high phosphorus content in water environment may be one of the key factors to promote the outbreak of dinoflagellate Peridiniopsis blooms.