三峡库区大宁河2010年春季水华特征

The Characteristics of Spring Algae Blooms in the DaNing River,Three Gorge Reservoir,2010

以大宁河春季水华期间调查数据为基础,运用数理统计分析手段,通过描述大宁河春季水华期藻类及主要理化因子分布特征,揭示出影响藻类生长的主要因子。结果表明:大宁河春季水华期水华河段水体氮、磷含量较高,总氮浓度为1.2～4.11mg/L,平均值为1.748mg/L,总磷浓度为0.027～0.615mg/L,氮磷比均值为17.5。春季水华藻类适宜的光照强度为1400～3800lx,水温为13.0～14.0℃时叶绿素a含量有最大增长,平均水温为13.4℃,藻密度与总氮、总磷、水温、DO、pH、浊度、高锰酸盐指数呈显著正相关关系,与透明度呈负相关关系。回水河段流速小于0.05m/s,流速是藻类生长最主要的限制因子。大宁河回水河段春季水华藻类分布较广,主要有甲藻门、绿藻门、硅藻门、隐藻门、蓝藻门、裸藻门和黄藻门7门28属,其中甲藻门分布最广,其次是绿藻门。春季水华优势种主要有甲藻门的拟多甲藻,绿藻门的衣藻、小球藻,硅藻门的直链藻,蓝藻门的色球藻等。

To elucidate relationships between phytoplankton and related environmental factors,phytoplankton and environmental parameters of water quality in the DaNing River during spring blooms were conducted using multivaviate statistical analysis.The results indicate that total nitrogen（TN） and total phosphorous（TPs） values range from 1.2 to 4.11mg/L and 0.027 to 0.615mg/L,respectively.In this study,the TN/TP ratios is 17.5.It is most likely that the algae blooming was strongly related to water temperature（13~14℃） and light intensity（1400~3800lx）.The results suggest that TN（r=0.903,P〈0.01）,TP（r=0.914,P〈0.01）,water temperature（r=0.528,P〈0.01）,DO（r=0.614,P〈0.01）,pH（r=0.450,P〈0.01）,TUR（r=0.509,P〈0.01） and CODMn（r=0.598,P〈0.01） are positively correlated with algae density,respectively.And algae density is negatively correlated with Transparency.The average flow velocity is less than 0.05m/s,and velocity is the main limiting factor for algae increasing.In the backwater areas of the DaNing River,28 genera belonging to 7 phyla were recorded.The maximum proportion of Pyrrophyta was observed during spring blooms period.The observed taxa were Pyrrophyta,Chlorphyta,Bacillariophyta,Cryptophyta,Cyanophyta,Euglenophyta and Xanthophyta.Chlamydomonus.sp and Chlorella uulgaris were the predominant algae genera during spring blooms period.