兰州市银滩湿地小生境沉积物中硅藻的属种分布及特征

Diatom distribution characteristics of a ecological niche in Yintan wetland of Lanzhou

通过采集兰州市银滩湿地秋(10月)、冬(12月)两季不同水环境中的表面沉积物,分析鉴定硅藻属种的分布和组合特征。结果表明硅藻优势种随采样点和采样时间发生变化。10月份以Gyrosigma scalproides、Cymatopleura solea var.regula、Navicula viridula var.rostellata、N.simplex、N.exigua、Nitzschia palea、N.angustata var.acuta、Cymbella affinis为相对优势种。12月份以Gyrosigma Parkerii、G.acuminatum、Navicula veneta、N.viridula var.rostellata、Nitzschia angustata var.acuta、N.palea、Cocconeis placentula为相对优势种。银滩湿地在秋季和冬季以指示淡水环境硅藻为主,底栖种和附着型种为特征。出现了一些指示中营养的有机污染种,表明了水质的营养化程度升高。有机质含量、pH、Cl-和P是中营养有机污染种主要的影响因素,表明银滩湿地的富营养化趋势较为明显。

The surface sendiments from the different water-environments of Autumn（Oct.） and Winter（Dec.） collected from the wetland of Yintan,Lanzhou City,and the analysis of the diatoms distribution and the character of the assemblages indicate that dominant diatoms varies with the changes of sampling locations and times.Gyrosigma scalproides、Cymatopleura solea var.regula、Navicula viridula var.rostellata、N.simplex、N.exigua、Nitzschia palea、N.angustata var.acuta、Cymbella affinis are dominated species in October.Gyrosigma Parkerii、G.acuminatum、Navicula veneta、N.viridula var.rostellata、Nitzschia angustata var.acuta、N.palea、Cocconeis placentula are dorminant species in December.The wetland is fresh-water in Autumn and Winter.The diatoms are characterized by the benthonic and settled species.The appeared organic polluted species indicate that it is the medium nutrition level,and it shows the increasing degrees of Nutrition in water condition.The key influencing factors are organic matter content,pH,Cl-and P of medium nutrition level and display a nutrition trends in the Yintan wetland of Lanzhou.