CONICET | Buscador de Institutos y Recursos Humanos

Abstract: The Iberá system is one of the largest wetlands in South America with scarce anthropicdisturbances. In this Mesopotamic region waters have low conductivity and the main nutrients aregenerally present in low concentrations. The shallow lakes of the Iberá system are surrounded byextensive swamps by which streams circulate. Phytoplankton density showed seasonal variations,with minima in autumn-winter and maxima in spring-summer. The northeastern shallow lakes werecharacterised by their high density with dominance of Cyanobacteria. The reduction in phytoplanktondensity and increase of diversity towards the south of the system was related to the development ofsubmerged vegetation. Phytoplankton density was higher in the limnetic area, where light and nutrientavailability is enhanced in relation to the vegetated area. The Iberá system presented more than 1000algal taxa and thus, it is one of the wetlands of higher diversity in South America. This complex systemis a potential center of dispersion of species from the Argentine Mesopotamia.