Spatial seasonal distribution of chromophoric dissolved organic matter in the Upper Paraná River floodplain environments (Brazil)

Abstract

Aim: Our aim was to identify dissolved organic matter (DOM) main sources in environments of the Upper Paraná River floodplain and their seasonal and spatial variation. Methods: Ultraviolet-visible and fluorescence spectroscopy were utilized. The samples were obtained from November 2007 to September 2008 in six lakes of the floodplain. Results: DOM quality differs among environments and also between rainy and dry season. The environments connected with Paraná River showed a high variation on the allochthonous/autochthonous proportion. Aquatic macrophytes might represent an important contribution to DOM in Garças and Osmar lakes. Conclusions: In general, environments connected to Paraná River have a greater influence of autochthonous DOC, while the others are most influenced by allochthonous inputs.