杭州西湖水域可培养异养细菌的群落多样性

Community diversity of cultivable heterotrophic bacteria in West Lake,Hangzhou

自 2 0 0 1年 10月～ 2 0 0 2年 10月对杭州西湖水域可培养异养细菌的群落结构和多样性进行了为期 1年的调查。水体中可培养异养细菌的年平均值只有 5 10CFU/mL。从季节变化来看 ,温度较低的 12月和 3月其数量相对较多 ,分别为 80 9和 75 7CFU/mL ,而温度较高的 5月和 10月只有 32 7和 330CFU/mL。表层底泥中可培养异养细菌的数量平均为 2 .2 7× 10 5CFU / g (以干泥计 ) ,其中长桥湾相对较多 ,为 3.0 6× 10 5CFU / g ,而湖心泥中只有1.70× 10 5CFU /g。从季节的变化看 ,也是冬季的数量比夏季高。调查还发现西湖水域优势菌的优势度高 ,多样性指数低。在三个湖区连续 1年的测定中总共只出现 14种类型的菌落 ,优势菌为假单胞菌属、肠杆菌科和气单胞菌属。水体中优势菌的优势度为 36 .8%～ 80 .4 % ,平均 5 4 .5 % ;多样性指数H介于 0 .6 82～ 1.787之间 ,平均 1.16 0。底泥中优势菌的优势度为 2 7.7%～ 72 .7% ,平均 5 1.7% ;多样性指数H介于 0 .80 9～ 1.774之间 ,平均 1.30 9。水体中的细菌有 95 %为革兰氏阴性杆菌 ,革兰氏阳性菌很少 ;产色素菌的比例相对较高 ,其中以产黄色素菌落为主 ,平均达 2 0 .1% ;芽孢杆菌所占的比例较低 ,只有 4 .2 4 %。而表层沉积物中产黄色素的菌落较少 ,只有 2 .0 7% ;?

We studied the community structure and diversity of cultivable heterotrophic bacteria in West Lake, Hangzhou from October 2001 to October 2002. Results showed that there were 510 CFU of bacteria per mL water and 2.27×10 5 CFU per gram of dry sediment. The bacterial population in water was higher in cold seasons than in hot seasons. In sediments, the bacterial population varied not only with seasons but also with dredging of the mud. Soon after dredging of mud in Changqiao,bacterial counts were about 0.81×10 5 CFU per gram in the new sediment. After three months, the bacterial population had increased to 4.60×10 5 CFU per gram. There were 14 types of cultivable heterotrophic bacteria in the West Lake ecosystem. The dominant types were Pseudomonas ,Enterobacteriaceae or Aeromonas, which accounted for 36.8%～80.4% of the total bacterial population in water column; and 27.7%～72.7% of those in sediments. Analysis of Shannon Wiener index ( H ) and Simpson index ( L ) indicated that the Lake had low bacterial diversity. The index H was between 0.682 and 1.787 in water columns; and between 0.809 and 1.774 in sediments, and the index L was between 0.196 and 0.662 in the water column, and between 0.179 and 0.572 in sediments. Among the bacteria from water column, 95% were Gram negative rods, and 20.1% produced yellow pigments. In sediments, about 85% of the bacteria were Gram negative rods and only 2.07% produced yellow pigments. Furthermore, the population of Bacillus was much higher in sediments than in the water column, suggesting that there are different niches in water column and sediments in West Lake despite the frequency of water mud exchange.