武汉机器荡子湖蓝藻水华优势藻种和土嗅味藻源鉴定

Identification on Preponderant Algae of Cyanobacteria Bloom and Geosmin Odor Source of Wuhan Jiqidangzi Lake

采用PCR扩增、基因测序技术对湖泊早春季节爆发蓝藻水华的优势藻种和土嗅味藻源进行鉴定研究,实验室条件下分别测定了不同光强和温度对优势藻生物量和土嗅素产量的影响,其中,光强和温度梯度分别为16、26、36μmol·m-2·s-1和16、26、36℃。结果表明,湖泊蓝藻水华的优势藻种为柔细束丝藻(Aphanizomenon gracile),富营养化湖泊中的强烈异味可能来源于柔细束丝藻的土嗅素。室内模拟实验显示柔细束丝藻叶绿素含量和土嗅素产量在低温和高光强时较高,实验范围内的低温强光环境有利于其生长;温度对柔细束丝藻生长量和土嗅素产量的影响较光强显著,适宜条件下土嗅素最高产量达6 555 ng·mg^(-1)。

Research indicates cyanobacteria blooms not only endanger water quality,but also produce neurotoxins and odorous matter. In order to scientifically predict water bloom,and then provide fundamental knowledge on the prevention and control of water bloom and odor,preponderant algae species of cyanobacteria bloom and geosmin odor source multiplied in early spring were identified by means of PCR amplification and gene sequencing technology. The effects of different temperature and light intensity on preponderant algae biomass and geosimin odor yield were also measured respectively under laboratory conditions. The preponderant algae were cultured at three temperatures( 16,26 and 36 ℃) and three light intensities[16,26,36 μmol · m-2·s-1]. The preponderant algae of cyanobacteria bloom was identified as Aphanizomenon gracile,and the strong smell of the eutrophicated lake might come from the geosmin of Aphanizomenon gracile. Laboratory simulation study indicate that the content of Aphanizomenon gracile chlorophyll-a and the yield of geosmin odor became higher at low temperature and high light intensity,indicating low temperature and strong light environment were favorable growth conditions. It was found that the effect of temperature was more significant than light intensity on Aphanizomenon gracile,and the highest yield of the geosmin odor was 6 555 ng·mg-1under favorable conditions.