香溪河库湾轮虫现状及水质评价初探

PRIMARY STUDIES ON PLANKTON ROTIFERS AND WATER QUALITY ASSESSMENT IN XIANGXI BAY OF THE THREE GORGES RESERVOIR

香溪河是长江三峡水库湖北省最大的支流。通过对香溪河库湾(下游河段)一周年的调查,发现轮虫80种,其中占优势的有13种。轮虫密度在不同样点差异显著,样点Ⅸ最低(仅为68.96 ind./L),样点Ⅵ最高(为1505.83ind./L);对9个样点进行聚类分析,可分为4组,第1组为样点Ⅰ至Ⅴ,第2组为样点Ⅵ,第3组为样点Ⅶ、Ⅷ,第4组为样点Ⅸ;除样点Ⅸ外,沿着水流方向,轮虫密度逐渐降低;在时间上差异也显著(P<0.01),9月份最高(2664.17ind./L),12月份最低(85.00ind./L)。水质评价表明香溪河库湾属于中污染。

Xiangxi River was the biggest tributary of the Three Gorges Reservoir in Hubei Province, which had a length of 94km, a catchment area of 3,099km^2 and a natural fall of 1540m. Since June 1st,2003 the segment of Xiangxi River from the river mouth to Xiakou had been formed the backwater region. In this region the spatial and temporal distribution of plankton rotifers were investigated at monthly intervals from July, 2003 to June,2004. Among the 80 rotifer species identified, 13 species were predominant, which were Synchaeta sp. , KerateUa cochlearis, Polyarthra trigla, Conochilus unicorni, Trichocerca lophoessa, Trichocerca gracilis, Brachionus angularis, Keratella valga, Tichocerca similes, Brachionus forfitcula, Brachionus Calyciflorus, Trichocerca porcellus and Pompholyx sulcata. A maximum density of 2459.23 ind./L was observed in September and the minimum of rotifer density was found in December（85.00 ind./L）. ANOVA was used in the variance analysis of rotifer density in different months, the result was found that rotifer density, Margalef and Shannon-Wiener diversity index significantly different（ n = 12, P 〈 0.01）,so the temporal dynamic of rotifer density in Xiangxi Bay was obvious. At the same time, the spatial distribution of ro tifers in this region was discussed. The highest density of rotifer was found in Site Ⅵ, the least density was found in Site Ⅸ. Rotifer density decreased along the water flow. And all the sites could be divided into 4 groups by the cluster analysis, the first group was from Site Ⅰ to Ⅴ ;the second group was Site Ⅵ ;the third group was Site Ⅶ and Ⅷ ;and the fourth group was Site Ⅸ. Rotifer density was evidently positive correlation with temperature, but negative correlation with water depth. The main factors regulating rotifer population were water temperature and food resource. Also in this article the relationship between rotifer and water quality was discussed.