Comparative limnology of South American floodplain lakes and lagoons

Abstract

The primary purpose of this study was to compare different lagoons from eight floodplains in South America (Amazon, the Upper Paraná, the Middle Paraná, Mogi-Guaçu, Araguaia, Pantanal, São Francisco and Orinoco floodplains). Secondly, the effect of water level upon selected limnological variables (important and frequently used variables in limnological studies) was evaluated. Data were obtained from published articles and dissertations. Some unpublished data from Upper Paraná, Amazon and Araguaia floodplains were also used. Despite the general differences among the floodplains such as climate, geology and limnological characteristics of the main river, certain constant patterns were found. Oxygen concentration was always higher during low water phase and, in general, the lagoons have an acid water independently of the period. By comparing the Amazon, Paraná and Araguaia floodplains, whose data are more abundant, high variability in chemical factors was found during the low water phase when measured by the variation coefficient. This result supports the hypothesis that the flood pulse acts as a regional process that increases similarity among the lagoons