Evaluation of geochemical biomarkers and salinity in sediment core in the Lagoa do Ribeirão in Paulo Lopes, SC

Abstract

Geochemical biomarkers are compounds present in the geosphere and are related to certain biological precursors, providing information about the environmental changes that have occurred or are occurring in aquatic ecosystems and their neighborhoods The Lagoa do Ribeirão, located in Paulo Lopes - SC, is the aquatic ecosystem examined in this study, mainly through geochemical biomarkers and salinity. Evidences obtained of increased salinity, silt+clay particle size fraction, total sulfur, dinosterol and smaller amounts of geochemical biomarkers of terrestrial sources indicate the predominance of marine environment, when the relative sea level was higher than the current level. There was a period of transition from marine to freshwater environment, characterized by the reduction of organic carbon and an increment in the amount of sand and biomarkers of terrestrial sources. After this period, the freshwater began to predominate in this lagoon, with higher amount of geochemical biomarkers of terrestrial origin such as linear alkanes n-C27, n-C29, n-C31, friedelin, taraxerol, β-sitosterol and campesterol and the reduction in salinity. The highest concentrations of biomarkers are located mainly in the east, southeast, south and southwest of the lagoon. These areas are close to the hills of Serra do Tabuleiro, the river Paulo Lopes entrance and exit of the river of Lagoa do Ribeirão.