广东省高州水库春季蓝藻水华成因初步探讨

Preliminary regulating factors of spring cyanobacteria bloom in Gaozhou Reservoir,Guangdong Province

高州水库为广东省茂名市重要的饮用水源地,2009年和2010年春季相继出现蓝藻水华,给居民饮水带来安全隐患.对高州水库2009年和2010年春季水华情况进行分析,结果表明:两年浮游藻类细胞密度最高分别达4.08×107cells/L和1.47×108cells/L,其中蓝藻所占比例分别为98.2%和98.7%,优势藻种均为鱼腥藻(Anabaena spp.)和铜绿微囊藻(Microcystis aeruginosa).水库中TN/TP比波动在28和64之间,磷为主要的限制性因子.叶绿素a含量波动在2.5mg/m3和31.6mg/m3之间,叶绿素a与pH(r=0.753,P<0.01)、DO(r=0.565,P<0.05)呈显著正相关.推断较高的水体稳定性、水温回升、氮磷营养水平接近水华发生的阈值是高州水库蓝藻水华发生的主要原因.

Gaozhou Reservoir is an important drinking water source of Maoming city of Guangdong province.Cyanobacteria blooms,occurring in spring of 2009 and 2010,had brought safe hidden trouble to residents.Based on the data collected from the reservoir in two springs,the highest densities of phytoplankton in the spring of 2009 and 2010 were 4.08×107cells/L and 1.47×108cells/L,and cyanobacteria densities accounted for 98.2% and 98.7% of total phytoplankton,respectively.The dominant species were Anabaena spp.and Microcystis aeruginosa in the two springs in the reservoir.The TN/TP ratios ranged from 28 to 64,phosphorus was the limiting factor for phytoplankton development.The chlorophyll-a concentration ranged from 2.5 to 31.6 mg/m3,and the correlation between pH（r=0.753,P0.01）and DO（r=0.565,P0.05） was excellent.It can be inferred that the main reasons of spring phytoplankton blooms were the high stability of water,water temperature rising and the nitrogen and phosphorus level close to the threshold value of spring phytoplankton blooms.