Phytoplankton of the Iberá system

Abstract

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