Phytoplankton biodiversity in Paraguay-Paraná rivers

Phytoplankton biodiversity in Paraguay-Paraná hydrographic basin was analized, including Paraguay and Paraná rivers and its floodplain. This contribution is based upon information published in taxonomic and ecological papers and the autor’s unpublished data. The phytoplankton community was structured by aproximately 800 taxa belonging (among Divisions and Classes) to eight taxonomics groups: Chlorophyta, Bacillariophyceae, Euglenophyta, Cryptophyta, Cyanophyta, Xanthophyceae, Chrysophyceae and Dinophyta. Five hundred ninety three taxa were registered in the river (principal channel) and 761 in the floodplain. In the river, species richness showed a decrease in North-South direction with a higher number of taxa in the Pantanal. Chlorococcales (Chlorophyta) was the Order with greater species richness (in both river and floodplain). It’s followed by Bacillariophyceae in the river and by Euglenophyta in the floodplain. The contribution of each taxonomic group to the abundance and species richness is different and may varie in the principal channel of the river and in the floodplain in relation to hidrossedimentological regimeFil: Zalocar, Yolanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentin