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

Periphyton in a run mesohabitat of a mountain stream: seasonal dynamics related to physicochemical parameters. 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.