河流型水库蓄水前水质、浮游植物群落结构与季节变化--以西江老口水利枢纽为例

摘要

Four times of sampling and investigating in Laokou section of Xijiang River were conducted to study the seasonal variations of water quality and phytoplankton community from October of 2013 to July of 2014.The results showed that the water quality of Laokou section achievedⅡclass of“Environmental quality standards for surface wa-ter”(GB3838-2002).And 56 species of phytoplankton were identified by microscope.The phytoplankton density ranged from 3. 563. 56 ×105 to 1. 75 ×106 cells/L.The seasonal variations were high in summer and autumn,low in winter and spring.The characteristics of phytoplankton cell density in dominant species have been changing from Cy-anophyta to Bacillariophyta to Cryptophyta to Chlorophyta.The nutrients,Chlorophyll and phytoplankton cell density were low in Laokou section,which was not suitable for phytoplankton mass-production.The changes of phytoplank-ton community and density were affected by water temperature,TP,TN,and the ratio of TN and TP.%于2013年10月—2014年7月对广西西江老口水利枢纽建成前老口断面进行了4次采样调查。结果表明：老口断面水质达到GB3838－2002Ⅱ类标准；水体中共检出浮游植物56种，浮游植物细胞密度范围在3．56×105～1．75×106个／L，呈现夏秋高、冬春较低的季节性变化特点；在细胞丰度组成上呈现由蓝藻型向硅藻－隐藻－绿藻混合型转变的趋势；老口断面营养盐、叶绿素和浮游植物细胞密度水平较低，未具备浮游植物大量繁殖的营养条件；浮游植物群落结构及密度变化受到水温、总磷、总氮及氮磷比的影响。