Tan Xiao, Kong Fanxiang, Zeng Qingfei, Cao Huansheng, Qian Shanqin, Zhang Min
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
J Environ Sci (China). 2009;21(7):892-9. doi: 10.1016/s1001-0742(08)62359-1.
In order to monitor the changes of Microcystis along with temporal and spatial variations, seasonal variation of Microcystis in Lake Taihu was investigated by 16S-23S rRNA internal transcribed spacer denaturing gradient gel electrophoresis (16S-23S rRNA-ITS DGGE) and microscopic evaluation. Samples were collected quarterly at four sites (River Mouth, Meiliang Bay, Cross Area, and Lake Center) from August 2006 to April 2007. Results showed that Microcystis dominated total phytoplankton abundance at the four sites in all seasons except winter. The average annual abundance of Microcystis was relatively high at River Mouth and Meiliang Bay, reaching 81.22 x 10(6) and 61.32 x 10(6) cells/L, respectively. For temporal variations, Shannon-Wiener diversity index (H') according to DGGE profile revealed the richness of Microcystis in summer (H' = 1.375 +/- 0.034) and winter (H' = 1.650 +/- 0.032) was lower than that in spring (H' = 2.078 +/- 0.031) and autumn (H' = 2.365 +/- 0.032) (P <0.05). While for spatial variations, the richness of Microcystis at River Mouth (H' = 2.015 +/- 0.074) was higher than at other sites during four seasons (P < 0.01). Very few differences of Microcystis diversity in the same season were observed among the other three sites (P > 0.05). Canonical correspondence analysis (CCA) was performed to elucidate the relationships between Microcystis operational taxonomic units (OTUs) composition and the environmental factors. Results of CCA revealed that temperature was strongly positively correlated with the first axis (r = 0.963), while TSS was negative correlated with the second axis (r = -0.716). Phylogenetic tree based on the sequencing results of target bands on DGGE gel indicated that samples collected in summer and winter constituted two separated clusters.
为监测微囊藻随时间和空间变化的情况，采用16S - 23S rRNA内转录间隔区变性梯度凝胶电泳（16S - 23S rRNA - ITS DGGE）和显微镜评估方法，对太湖微囊藻的季节变化进行了研究。于2006年8月至2007年4月每季度在四个位点（河口、梅梁湾、交叉区域和湖心）采集样本。结果表明，除冬季外，微囊藻在所有季节均在四个位点的浮游植物总丰度中占主导地位。河口和梅梁湾的微囊藻年均丰度相对较高，分别达到81.22×10⁶和61.32×10⁶个细胞/升。在时间变化方面，根据DGGE图谱的香农 - 维纳多样性指数（H'）显示，夏季（H' = 1.375±0.034）和冬季（H' = 1.650±0.032）微囊藻的丰富度低于春季（H' = 2.078±0.031）和秋季（H' = 2.365±0.032）（P <0.05）。在空间变化方面，河口的微囊藻丰富度（H' = 2.015±0.074）在四个季节均高于其他位点（P <0.01）。在其他三个位点之间，同一季节微囊藻多样性的差异极小（P>0.05）。进行了典范对应分析（CCA）以阐明微囊藻操作分类单元（OTUs）组成与环境因素之间的关系。CCA结果显示，温度与第一轴呈强正相关（r = 0.963），而总悬浮固体（TSS）与第二轴呈负相关（r = -0.716）。基于DGGE凝胶上目标条带测序结果的系统发育树表明，夏季和冬季采集的样本构成两个独立的聚类。
