两座抽水型水库蓝藻种群与微囊藻毒素的比较分析

Comparative Analysis of Cyanobacteria Populations and Microcystin in Two Pumped Storage Reservoirs, South China

摘要:

2008年每隔两月调查1次广东省两座抽水型水库：凤凰山水库和南屏水库的蓝藻组成与微囊藻毒素分布特征。结果共检测到蓝藻有14属，主要为丝状体和群体种类，常见的有假鱼腥藻属(Pseudanabaena)、蓝纤维藻属(Dactylococcopsis)、湖丝藻属(Limnothrix)、拟柱孢藻属(Cylindrospermopsis)和色球藻属(Chroococcus)。两座水库的蓝藻细胞密度为119~137373 cells mL-1，微囊藻毒素浓度为0~2.26 μg L-1。凤凰山水库的全年微囊藻毒素浓度均低于国家安全标准(1 μg L-1)，最高浓度出现在3月份；南屏水库在丰水期微囊藻毒素浓度高于凤凰山水库，最高浓度出现在7月(2.26 μg L-1)。长水力滞留时间的凤凰山水库的蓝藻细胞密度比短水力滞留时间的南屏水库高出1个数量级。两座水库蓝藻细胞密度的峰值都出现在枯水期的3月，这主要与温度和调水量变化引起的营养盐季节性变化有关。假鱼腥藻、湖丝藻和拟柱孢藻是凤凰山水库的优势蓝藻种类，大多数情况下相对丰度超过50%。在南屏水库，枯水期蓝藻以丝状体种类为优势，丰水期则以群体种类为优势。温度和调水量的季节性变化引起的营养盐季节性变化可能是引起南屏水库不同生活类型优势蓝藻种类季节演替的主要因素。

Abstract:

The distribution of cyanobacteria and microcystin in two pumped storage reservoirs, Fenghuangshan Reservoir and Nanping Reservoir in Guangdong Province was bimonthly investigated in 2008. Forteen genera were identified, and most of them were filamentous and colonial ones, such as Pseudanabaena, Limnothrix, Dactylococcopsis, Cylindrospermopsis and Chroococcus. Cyanobacteria abundance in two reservoirs ranged from 119 to 137373 cells mL-1, and microcystin concentration from 0 to 2.26 μg L-1. In Fenghuangshan Reservoir with relatively long retention time (160 d), microcystin concentration was lower than the national standard for drinking water of 1 μg L-1 throughout the year, which the maximum was in March. In the short retention time (60 d) reservoir, Nanping Reservoir, the concentration of microcystin was higher than that in Fenghuangshan reservoir in the flood season with the maximum in July. In Fenghuangshan Reservoir, the abundance of cyanobacteria was one order higher than that in Nanping reservoir. Maximal abundance occurred in dry season (March) in both the reservoirs, and nutrient loading related to pumping strategy and temperature were two possible factors in seasonal variation of cyanobacteria abundance. In Fenghuangshan Reservoir, Pseudanabaena, Limnothrix and Cylindrospermopsis were dominant in cyanobacteria and contributed more than 50% of the total abundance at most of time. In Nanping Reservoir, cyanobacteria was dominated by filamentous species in dry season and by colonial species in flood season. The temperature and nutrient loading related to pumping strategy seemed to key factors inducing cyanobacteria seasonally dominated by different ecotypes of species in Nanping Reservoir.