武汉东湖甲藻水华与环境因子的关系

Relationship between Peridiniopsis sp. and environmental factors in Lake Donghu,Wuhan

由于水体富营养化等原因，在全球范围内，水华频繁爆发．近来，发现武汉东湖出现了一种拟多甲藻（Peridiniopsis sp．）水华，该藻是广温性种，水华持续时间较长，最高细胞密度达2541．44×10^4 cells／L．研究了武汉东湖拟多甲藻水华种群动态及其与环境因子之间的关系．相关分析表明，拟多甲藻密度和表层总磷、1．2m处的总氮以及表层硝酸盐浓度成显著正相关，但是总磷、溶解性磷酸盐、总氮、磷酸盐以及氨氮浓度在形成明显水华前大幅度升高，水华消亡时，处于低谷．适合的光照条件，也是拟多甲藻水华形成的刺激因子之一．另外，从一些采样点浮游植物组成及分布来看，风在一定程度上加重了水华表观的严重程度．此外，还观察到了水华的消亡及其发生过程，水华消亡时，大量拟多甲藻下沉．分析认为，水华的发生是多种环境因子综合作用的结果．

Because a lot of nitrogen and phosphorus flow into lakes and rivers, water bloom frequently occurs in world scope. Recently a sort of Peridiniopsis sp. bloom was appeared in Lake Donghu, Wuhan. The Peridiniopsis sp. can adapt well to a large range of temperature. The algal bloom lasted a long time and the maximum density of Peridiniopsis sp. reached as high as 2.54 × 10^7 cells/L. In the paper, population dynamics of Peridiniopsis sp. and its relationship with environmental factors in Lake Donghu were studied. The correlation analysis indicated Peridini- opsis sp. be remarkable positive correlation with the concentrations of TPsurface, TN1.2menters and NO3-Nsurface. However, the concentrations of TP, TOP, TN, TON, PO4-P and NH4-N were raised just a day before blooming and fell to lowest after blooming. Suitable strength of illumination may be a triggering factor for blooming. In addition, it can be found from the composition and distribution of phytoplankton in some sampling stations that in certain degree wind can make Peridiniopsis sp. gather and cause bloom. The development, occurring and dying out of algal bloom was observed. When the algal bloom died out, a lot of Peridiniopsis sp. sunk down toward lower layer. By analyzing, authors consider many environmental factors lead to water bloom together.