青山水库轮虫群落结构特征的时空差异对水质变化的影响

为研究青山水库轮虫群落结构特征的时空差异对水质变化的影响,对其进行了四个季度的采样调查。结果共发现轮虫物种30种,分属于9个科,其中优势种为长肢多肢轮虫和针簇多肢轮虫,后者是一种污染指示种,表明水质处于中度污染状态。轮虫平均密度为171 ind./L,平均生物量为0.0158 mg/L。通过对水库理化因子与轮虫群落生物指数进行相关性分析,初步确定水温和溶解氧是青山水库轮虫群落演替的主要影响因子。根据轮虫群落结构聚类分析表明,青山水库分为四大区域。另外,主成分分析结果表明水质的下降可能与营养盐的的增加有关,特别是氮的输入。综合理化指标、营养状态指数、轮虫多样性指数以及优势种指示种等多种评价方法,结果表明2012—2013年青山水库水质属于中度—重度污染之间,营养程度为中度富营养状态,青山水库水环境污染严重。依据理化指标和轮虫群落结构特征来评价水质状况,得到的结果基本一致,因此轮虫可以作为青山水库一个较为理想的检测指标。

EFFECTS OF TEMPORAL AND SPATIAL DIFFERENCE IN ROTIFER COMMUNITY STRUCTURE CHARACTERISTICS ON WATER QUALITY VARIATION IN THE QINGSHAN RESERVOIR

4 seasonal sampling was conducted to study the effects of the temporal and spatial difference in rotifer community structure in response to water quality variation in the Qingshan Reservoir in upstream of East Tiaoxi River, Zhejiang. 30 species and 9 families were identified. Dominant species were Polyarthra dolichoptera and Polyarthra trigla, of which the latter is a pollution indicator species, showing that the water was in the state of moderate pollution. The annual average density of rotifer was 171.8ind./L, and the annual average biomass was 0.0158mg/L. Correlation analysis between reservoir physical and chemical factors and rotifer community biological index shows that water temperature and dissolved oxygen were the main impact factors on rotifer community succession. According to the community structure of rotifers, the reservoir could be divided into 4 areas. Principal component analysis shows that water quality declining might be associated with the increase of nutrients, especially nitrogen. Combining the physicochemical index, trophicstate index, diversity index, and dominant species of rotifers indicator species, we assume that the water quality was between moderate and serious contamination level from year 2012 to 2013. The data also indicate that the nutrition level is in moderate eutrophication, and environment pollution in the reservoir water was serious. Since the physicochemical index and rotifer bio-indicators reflected the results of water quality consistently, we suggest that rotifer community can be used as a biological index to evaluate the quality of water mass in the Qingshan Reservoir.