黄河水库水质评价——基于浮游植物群落周年变化

Annual Dynamics of Phytoplankton Community and Water Quality Evaluation of Huanghe Reservoir

为掌握黄河水库浮游植物群落结构与水质现状,分4个季节进行周年采样监测.通过单因子、综合营养状态指数、浮游植物现存量及种类组成等方法综合评价黄河水库的富营养化状态.结果显示:从水质指标来看,主要污染物为氮营养盐,其年均值可达3.6mg/L.综合营养状态指数变化范围为37~59,以冬季最高,富营养化最严重.全年共检测到浮游植物6门75种(属),主要为蓝藻门和绿藻门,优势种为假鱼腥藻(Pseudanabaena)、尖头藻(Raphidiopsis)、拟柱孢藻(Cylindrospermum)、颤藻(Oscillatoria)、纤维藻(Ankistrodesmus).浮游植物密度变化范围为1.68×10~7~3.62×10~7个/L,生物量变化范围为5.6~12.9mg/L.在各门类藻类中,蓝藻在全年均有较大数量(大于10~7个/L),预示着水体可能受到水华的威胁.同时优势种假鱼腥藻有产微囊藻毒素的潜力,对水体可能带来更为深远的危害.从浮游植物优势种、群落结构、密度、生物量、综合营养状态指来看,水库水质为中营养到富营养化状态,因此,要加强水质管理,降低爆发蓝藻水华的风险.

In order to learn about the current situation of phytoplankton community structure and water quality in the Huanghe Reservoir,four samplings of the reservoir water were taken respectively in four seasons.The eutrophication status of the Huanghe reservoir was comprehensively evaluated by means of the single factor,trophic level index TLI（∑）,phytoplankton stock and species composition.The results showed that：in terms of the water quality,the major pollutant is nitrogen nutrient salt with its annual average value reaching up to 3.6 mg/L.TLI（∑）ranged from 37-59,with the highest value and the most serious eutrophication detected in winter.A total of 75 genera（falling into 6 phyla）of phytoplanktons（chiefly Cyanophyta and Chlorophytawere）were detected throughout the year,of which the dominant genera were found to be the Pseudanabaena,Raphidiopsis,Cylindrospermopsis,Oscillatoria,and Ankistrodesmus.The phytoplankton density varied in the range of 1.68 to 3.62×107 ind/L,and the biomass varied from 5.6 to 12.9 mg/L.Among the 6 phyla of phytoplanktons,the cyanobacteria was found to have the largest number（reaching 107 ind/L）throughout the year,indicating a risk of water algal bloom in the waters.At the same time,the dominant genus,Anabaena,has the potential to produce microcystic toxins,which may cause greater far-reaching damage to the waters.Juding from the indices of dominant phytoplanktons,community structure,density,biomass,and TLI（∑）,the reservoir water quality is in a state of medium to eutrophication.Thus without a better water quality management,a risk of cyanobacteria bloom might come true.