应用硅藻指数评价渭河流域水生态健康状况

应用硅藻指数进行河流健康评价的研究日益广泛.本研究于2012年10月对渭河流域60个点位进行采样调查,应用Spearman相关分析法分析硅藻指数与水环境因子的关系,并根据硅藻指数生态健康分类标准对渭河流域水生态健康状况进行评价.结果表明,渭河流域共采集到硅藻26属221种,隐头舟形藻(Navicula cryptocephala)、谷皮菱形藻(Nitzschia palea)、扁圆卵形藻(Cocconeis placentula)、小形异极藻(Gomphonema parvulum)和极细曲壳藻(Achnanthes minutissima)等为主要优势物种.实验共计算出12个硅藻指数,除IDAP指数外,其余11个指数均与河宽显著相关,仅DI-CH指数与溶解氧显著相关,SHE、IPS和DI-CH指数与NO2和NH+4显著相关.基于硅藻指数生态健康分类标准,12个硅藻指数评价结果相差较大,IDAP、IPS、IBD和LOBO指数评价结果较好点位占45%以上,而TDI、IDP、CEE和DI-CH指数评价结果较差的点位较多,占45%以上,其余指数评价结果为一般水平.

Assessing water quality with diatom indices in the Wei River basin

Diatom indices have been widely used to evaluate health of aquatic ecosystem of freshwater bodies.Sixty sampling sites were chosen to investigate correlation between diatom indices and water quality in the Wei River basin in October 2012.A total of 221 diatom taxa from 26 genera were identified.The richest species included Naviculacryptocephala,Nitzschiapalea,Cocconeisplacentula,Gomphonemaparvulum and Achnanthesminutissima.By Spearman's correlation analysis,all diatom indices showed significant correlation with river width,except IDAP.Only DI-CH showed significant correlation with dissolved oxygen.SHE,IPS and DI-CH showed strong correlation with NO-2 and NH+4 .Ecological state was classified into five different types according to Lenoir and Coste.IDAP,IPS,IBD and LOBO diatom indices performed better than other indices,healthy sites accounted for more than 45%.On the contrary,TDI,IDP,CEE and DI-CH indicated that health of the Wei River basin was relatively poor.The rest of diatom indices tended to show a moderate condition.