Perifiton en el mesohábitat de corredera de un arroyo serrano: dinámica estacional en relación a variables físico-químicas

composition and distribution of periphytic algae in a run mesohabitat of the stream achiras, southwest of rio cuarto, cordoba, were analyzed seasonally during 2005-2006. three sites were selected for sampling in the longitudinal gradient of a mountainous and piedmont area, where the construction of a dam is considered. this research provides the first results on the algal periphytic community and lays the groundwork for a deepening future. a total of 267 taxa were identified, the class bacillariophyceae contributed with 174 taxa, chlorophyceae with 78 and cyanophyceae with 15. the maximum similarity between samples was 100%, corresponding to sites 1 and 2 during the spring. the highest average density was 320.486 org.cm-2 in site 3 during summer. the classification of samples separated two main groups and formed subgroups. the cca, which was performed considering samples and species, showed a separation of site 3 located in the piedmont, with higher percentage of small size sediment and less speed flow, regarding the others. sites 1 and 2 were interpreted, in general, by a ph gradient. all groups formed by the classification were integrated mostly by organisms of biraphidales order.