Nutrient and sediment fluxes in microbasins with different conservation states in the northeastern Brazil

The implications of land use change in small watersheds through the conversion of forests to agropastoral areas have altered the natural nutrient cycle, intensifying exports under freshwater ecosystems. This study aimed to investigate the land use effects on nutrient and sediment exports in two small watersheds in northeastern Brazil to understand if anthropogenic disturbance alters the structure end functioning of these systems. Thus, land use mapping and hydrological treatment of a digital elevation model were made to characterize the basins. Water samples were collected monthly from Aug. 2016 to Jan. 2017 to evaluate suspended sediments and dissolved nutrient fluxes ( NH 4 + , NO 3 − , NO 2 − , PO 4 3 − , and dissolved organic nitrogen and phosphorus). The results indicated that land use change had a greater influence on exports from the most disturbed basin, where the nutrient and sediment increments were respectively an average 6.61 and 5.81 times higher than the most preserved basin. Thus, the conservation status of the forest cover has influenced the assimilation capacity of diffuse loads, highlighting the differences between the microbasins of this study.