SEASONAL OPTICS IN THE PARAÍBA DO SUL RIVER WATERS (CAMPOS DOS GOYTACAZES, RJ): METRIC REFERENCES TO MONITORING NATURAL WATERS?

Abstract

This study investigates the spring-winter seasonal behavior of the inherent optical properties (IOPs) of chromophoric dissolved organic matter (CDOM) in the Paraiba do Sul river, at Campos dos Goytacazes (Rio de Janeiro state, Brazil). In each season 12 samples were collected weekly, resulting in 24 samples as a whole. The IOPs of CDOM -- herein referred to as optical variables -- were characterized through coeffi cients of absorption (aCDOM and a*CDOM) and spectral slope (S) at 280-700nm. The results served as a template for building a conceptual model about the dynamics of chromophoric dissolved organic matter in the studied ecosystem over the seasons. Albeit descriptive the present study illustrates how emerging optical patterns can contribute to the characterization of an aquatic ecosystem, which is of potential interest for the management and monitoring of natural waters.