固城湖及上下游河道富营养化和浮游藻类现状

于2009年4月(枯水期)、7月(丰水期)在固城湖及芜申线高淳段航道选取19个调查站点采集水样,测定水体理化特征、细菌总数、浮游藻类种类、数量等指标,并采用富营养状态指数法和Shannon-Wiener多样性指数法对水质污染现状进行研究和评价.结果表明,固城湖上游水阳江和固城湖湖区水质较好,处于轻度富营养化状态,官溪河污水处理厂排污口附近和下游胥河处于中度富营养化状态,并且综合富营养化指数在下游逐渐增高.目前固城湖及其上下游河道水质主要为氮磷污染,有毒、有机污染物的影响较小.调查期间共发现浮游植物9门22科36属74种.4月份固城湖湖区蓝藻数量占优势,达56%,其次是绿藻;上下游河道以绿藻和隐藻占优势,比例在30%左右.而7月份所有采样点蓝藻数量占绝对优势,均在80%以上,湖区藻类生物多样性指数明显高于其他区域.

Assessment of trophic levels and phytoplankton variation in Guchenghu Lake and canal route

Physico-chemical data(including nutrients,BOD5,suspended organic matter),microbial variables(bacteria abundance) and phytoplankton species and biomass were determined on April(withered water period) and July(high water period) 2009 from 19 sampling sites in Guchenghu Lake and Wushen canal route.The water pollution status was evaluated based on trophic level index and Shannon-Wiener index.The Guchenghu Lake and Shuiyangjiang River showed light eutrophication level with better water quality,while the Guanxihe River and Xuhe River showed middle eutrophication level characterized by heavy human and natural pressure.The trophic level index increased with a downward trend in the downriver water.Nitrogen and phosphorus were the main water pollutants in the study area,while the poisonous and organic matter pollution could be ignored.Nine phylum,22 familia,36 genus,74 species phytoplankton were found in the research.The cyanobacteria abundance dominated and the chlorophyta was in the second place in April in the Guchenghu Lake,while in the canal route the chlorophyta and cryptophyta were the main phytoplankton species.Cyanobacteria had the dominance ratio in all sampling sites in July,and the Shannon-Wiener index in Guchenghu Lake was much higher than that in other sites.