Water quality study of the Condor and Capivara Streams, Porto Alegre Municipal District, RS, Brazil, using epilithic diatom biocenoses as bioindicators

The aim of this work was to evaluate the water quality of two urban streams, Condor and Capivara, in the Municipal District of Porto Alegre, RS, Brazil, by measuring physical, chemical and biological variables. Between May 1999 and August 2000, six field trips were taken to sample five sites distributed along the streams. Multivariate canonical correspondence analysis (CCA) was applied for the complete evaluation of physical, chemical and biological data. It was confirmed that phosphate had the largest impact on ordination and exhibited an evident eutrophication gradient. Mayamaea atomus, Amphora montana, Sellaphora pupula and Cyclotella meneghiniana were extremely abundant under such conditions.