Using diatom assemblage to assess the water quality in Heilongjiang river (Heihe part)

摘要

Heilongjiang river is the third largest river in China,it flow through Heihe city,belonging to the up and middle streams of Heilongjiang river.This study aims to be the first step to (i) identify diatom type assemblages in this part of Heilongjiang river,and (ii) find which ecological factors explain most of the variation,(iii) find the most effective indicate species.To achieve this,we collected physical,chemical and diatom community data from six sites in Heilongjiang river (Heihe part) from 2006 to 2007,for a total of 260 samples.106 taxa were identified as diatom.Species such as Cocconeis placentula var.euglypta (Ehr.) Cl.,Cymbella tumida (Gerg.) Cl.,Melosira distans var.alpigena Grun.and Melosira varians Ag.are the most common species in all sites in the three seasons.The diatom assemblages changed in different sites and seasons.Species composition in site Ⅲ are different variously with other sites,provide a good chance for us to study the tolerance of the species,compared with other sites,several species which are tolerant of the pollution are observed.Relationship between sample sites and environmental factors were examined using PCA,all the sites can be divided into three group,with site Ⅰ,Ⅱ and Ⅳ have lower BOD and higher DO,indicate good water quality,site Ⅲ have higher TN,TP,BOD,COD indicate the poor water quality.Relationships between diatom communities and environmental factors were examined using Canonical Correspondence Analysis (CCA).There were strong correlations between diatoms and environmental factors,especially BOD,TP and water temperature.Heilongjiang river was characterized by mostly oligosaprobic/β-mesosaprobic taxa.Species which can be indicator for the TP,TN et al.were also found.