Abstract

AMAIDEN, M. Andrea  and  GARI, E. Noemí. Periphyton in a run mesohabitat of a mountain stream: seasonal dynamics related to physicochemical parameters. Bol. Soc. Argent. Bot. [online]. 2011, vol.46, n.3-4, pp.235-250. ISSN 1851-2372.

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.

Keywords : Periphyton; Stream Achiras; Diatoms; Mountainous area.

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