海河天津段微囊藻及其毒素的空间分布及与水环境因子的关系

采取荧光定量PCR技术及ELISA酶联免疫吸附法，以mcyD基因和PC-IGS基因为靶基因对夏季蓝藻暴发期间海河天津市区段的产毒微囊藻种群丰度和毒素含量进行了研究.结果表明：夏季海河天津市区段微囊藻种群丰度具有明显差异性：产毒微囊藻种群丰度为1.16×10⁴~2.48×10⁷copies/mL占总微囊藻种群的4.25%~28.59%.藻毒素含量最高点为8号采样点天津站，每升水体中藻细胞共含毒素195.51μg，除去藻细胞水中毒素浓度为0.97μg/L.总的来说，海河天津市区段微囊藻总基因拷贝数较高，产毒微囊藻丰度在不同采样点间差异较大，影响水体中微囊藻丰度的最主要环境因素是pH值.海河水体中毒素含量没有超过安全阈值，但是单位体积水体中藻细胞内毒素含量很高，具有较高的毒素释放潜力，可能对下游河口生态系统造成潜在威胁.

The spatial distribution of Microcystis and microcystin and its relationship with environmental factors in Haihe Tianjin City

The spatial distribution of Microcystis and microcystin in Haihe River during water bloom were investigated using quantitative real-time PCR (qPCR) and ELISA techniques. Microcystin synthetase gene (mcyD) and PC-IGS fragments were used as the target the total microcystin population and the potential microcystin-producing subpopulation. The results showed that microcystin existed as a mixed population of potentially toxic and non-toxic genotypes in Haihe River. There was significantly spatial variation in the abundance of microcystin-producing Microcystis. The abundance of microcystin-producing Microcystis subpopulation was ranged from 1.16×10⁴ to 2.48×10⁷ copies/mL and the ratio of its abundance to total microcystin varied from 4.25% to 28.59%. The peak value of microcystin was site point 8, which 1mL water contained 195.51μg microcystin in Microcystis algae cells and 0.97μg/L in water. To sum up, total abundance of Microcystis remained a high level in Haihe Tianjin region. The toxin of Microcystis showed various among different sampling sites. The most significant impact factors for Microcystis' abundance was pH value. However, the content of microcystin is not upon the value of WHO's threshold. But the intercellular toxin in a given volume of water remains a high level, which may cause the potential risk to the ecosystem of down flow estuary.