Studies on the Water Bloom of Toxic Alga, Microcystis Viridis

通过野外和室内实验对有毒微囊藻水华进行了研究。1988-1990年对霞浦湖微囊藻优势种的变化进行了研究。M.铜绿f. aeruginosa和M.水华在夏季占优势，而M.秋天，绿色植物成为了主要植物。相关分析表明，在不同的生长季节，M.铜绿假单胞菌（M. aeruginosa）的立群和水温的影响; viridis和M. wesenbergyst在水温上没有表现出相关性。温度和光照对M. viridis N-1和M. viridis NIES 102进行分批培养。最大比生长率M. viridis N-1和M. viridis NIES 102分别在25 ℃和30 ℃下观察到。M.绿色微囊藻比其他微囊藻能在较低的温度下生长。M. viridis N-1在连续光照下不能生长， ...更多信息 f 2，000 lx，但在周期性光照下可以生长。比生长速率为0.001; viridis比其他微囊藻低。这些结果表明M.此外，还研究了重金属对微囊藻生长的影响。铜、镉、钴对蓝藻M. aeruginosa K3A、M.在液体培养基中测定了蓝藻、鱼腥藻和绿色藻类椭圆小球藻。铜<50>对M. aeruginosa K3A、M. viridis、绿绿拟步行虫A. arrinis、C.结果表明，铜对这些藻类的生长毒性最大，其次是镉和钴。3种蓝绿色藻对铜的敏感性比绿色藻C.唇虫总科。EDTA、EGTA等螯合剂对铜的毒性有明显的缓解作用。霞浦湖表层水中铜浓度为0.017 μ M，与蓝藻EC_2值基本一致<50>。铜<50>对M.铜绿假单胞菌K3 A在湖水中比在液体培养基中大3倍。根据这些事实，可以推测湖水中的天然配体刺激了蓝藻的生长，从而导致蓝藻水华。少

We studied the water bloom of toxic alga Microcystis viridis in the field and laboratory experiment. A field study was carried out from summer to fall between 1988-1990 to clarify the change in the dominant species of Microcystis in Lake Kasumigaura. M. aeruginosa f. aeruginosa and M. flos-aquae were dominant in te summer, but M. viridis became dominant in the fall. A high correlation was found between the standing crop of M. aeruginosa and the water temperature, but the standing croup of M. viridis and M. wesenbergii showed no correlation in the water temperature. Effects of temperature and illumination on the specific growth rates and the algal yield of M. viridis N-1 and M. viridis NIES 102 were studied with a batch culture. Maximum specific growth rates of M. viridis N-1 and M. viridis NIES 102 were observed at 25 and 30^0C, respectively. M. viridis could grow at lower temperatures than the other species of Microcystis. M. viridis N-1 could not grow at the continuous illumination o … More f 2,000 lx but could grow at the periodic illumination. The specific growth rate of M. viridis was lower than those of other species of Microcystis. These results suggested that M. viridis was more difficult to dominate than other Microcystis in summer.Moreover, we studied the effect of heavy metals on the growth of Microcystis spesies. Toxicity of copper, cadmium and cobalt on the growth of blue-green algae M. aeruginosa K3A, M. viridis, Anabaena affinis and green algae Chlorella ellipsoidea was determined in the liquid medium. The EC_<50> (effective concentration, 50% inhibition of the specific growth rate of control) of copper for M. aeruginosa K3A, M. viridis, A. arrinis, C. ellipsoidea were 0.019muM, 0.023muM, 0.018muM and 0.58muM, respectively, Copper showed the severest toxicity to the growth of these glgae compared with cadmium and cobalt. The sensitivity to copper of three species of blue-green algae was 30 times higher than that of the green algae C. llipsoidea. Chelating agents such as EDTA and EGTA showed the stroug reducing effect on the copper toxicity. Copper concentratin in the surface water of Lake Kasumigaura was 0.017muM, which was the almost same to the value of EC_<50> for blue-green algae. However, the EC_<50> of copper for M. aeruginosa K3A in the lake water was found to be 3 times larger than in the liquid medium. From these facts, it is assumed that natural ligands in the lakewater stimulated the growth of blue-green algae to make algal bloom. Less