Urbanization increases carbon concentration and pCO2 in subtropical streams

Urbanization growth may alter the hydrologic conditions and processes driving carbon concentrations in aquatic systems throughlocal changes in land use. Here,we explore dissolved carbon concentrations (DIC and DOC) along urbanization gradient in SantaCatarina Island to evaluate potential increase of CO2 in streams. Additionally, we assessed chemical, physical, and bioticvariables to evaluate direct and indirect effects of urbanization in watersheds. We defined 3 specific urbanization levels: high(> 15% urbanized area), medium (15–5% urbanized area), and low (< 5% urbanized area) urbanization. The results showed thatlocal changes due to growth of urban areas into watersheds altered the carbon concentrations in streams. DOC and DIC showedhigh concentrations in higher urbanization levels. The watersheds with an urban building area above 5% showed pCO2 predominantlyabove the equilibrium with the atmosphere. These findings reveal that local modifications in land use may contribute tochanges in global climate by altering the regional carbon balance in streams.