大茶湖浮游藻类调查与水质初步评价

Investigation of phytoplankton and preliminary evaluation of water quality in Dacha Lake

为了解武汉市大茶湖的水质状况,2010年6月至2011年5月对该湖区的浮游藻类组成进行周年调查。从大茶湖的定性、定量样品中共鉴定出浮游藻类7门60属89种。根据浮游藻类的种类及数量,利用指示生物法和藻类多样性指数法(Margalef和Shannon-Weiner多样性指数)对其水质进行了初步评价。大茶湖浮游藻类群落组成中,绿藻门和蓝藻门在种类和数量上均占据优势,次之为硅藻门。污染指示藻类中,指示富营养型(α-ms)和中-富营养型(β-α-ms)的藻类占据优势,分别占污染指示藻类总数的48.72%和23.08%。藻类的Mar-galef和Shannon-Weiner多样性指数变化范围分别为1.45～2.19和1.64～2.95。水质评价结果显示:大茶湖水体处于中度污染(α-中污或β-中污)范围内,营养化状态为富营养型(α-ms或β-α-ms),而藻类污染指示类群显示其营养状态以富营养型中的α-ms型为主。

In order to understand the water quality condition of Dacha Lake in Wuhan,composition of phytoplankton in the lake was investigated from June 2010 to May 2011. A total of seven phyla, 59 genera and 89 species of phytoplankton were identified from qualitative and quantitative samples. Based on the species and quantity of phytoplankton, biological assessment of water pollution and eutrophication condition was conducted by using the methods of indicator organism and biotic diversity index （Margalef and Shannon-Weiner index）. In the phytoplankton community,Chlorophyta and Cyanophyta were domi- nant in both alga species and quantities, followed by Bacillariophyta. Of the pollution-indicating phytoplankton, the algae indicating a-ms and β-α-ms types of eutrophication were dominant, accounting for 48. 72 % and 23.08 % of the total, respectively. The Margalef index and Shannon-Weiner index for phyto- plankton ranged from 1.45 to 2. 19 and from 1.64 to 2. 95, respectively. The results indicated that the water quality of Dacha Lake was of moderate pollution （α- or β- moderate pollution）, and the trophic sta- tus was in the state of eutrophication （α-ms or β-α-ms）, mainly in the type of a-ms as revealed by the pollution-indicating algae.