02130naa a2200313 a 450000100080000000500110000800800410001910000210006024500970008126000090017852012650018765000290145265000110148165000230149265000120151565000230152765000080155065300150155865300110157365300230158465300210160765300240162865300180165265300250167070000190169570000250171470000190173977300580175819018782011-10-04       2011    bl uuuu     u00u1 u    #d1 aSOUSA, E. dos S.  aDissolved carbon in an urban area of a river in the Brazilian Amazon.h[electronic resource]  c2011  aThe main objective of this study was to evaluate dissolved organic and inorganic carbon dynamics along upstream and downstream reaches of the Acre River draining the city of Rio Branco, in the state of Acre, Brazil. Dissolved organic carbon (DOC) concentrations in the Acre River were significantly higher during the wet season, ranging from 385 ± 160 to 430 ± 131 IJM among the stations, with no difference in upstream and downstream concentrations. Dissolved inorganic carbon (DIC) showed an inverse pattern, with higher concentrations in the dry season, ranging from 816 ± 215 to 998 ± 754 IJM among the stations, as well as no difference in upstream and downstream DIC concentrations. Bicarbonate was the dorninant DIC fraction and was mainly observed during the dry season. Due to lower pH values during the wet season, CO2 partial pressure (PC02) in the Acre Ri ver was higher in the wet season, with values ranging from 4,567 ± 1,813 to 4,893 ± 837 ppm among the stations. Our results indicate that, although the Acre River drains a large city with significant sewage disposal into the river, seasonal hydrological processes are the main driver of dissolved carbon dynarnics, even in the downstream study reach directly influenced by urbanization.  aDissolved organic carbon  aRivers  aSeasonal variation  aCarbono  aQualidade da água  aRio  aAcre River  aAmazon  aCarbono dissolvido  aDissolved carbon  aSeasonal variations  aUrban impacts  aVariações sazonais1 aSALIMON, C. I.1 aFIGUEIREDO, R. de O.1 aKRUSCHE, A. V.  tBiogeochemistry, Dordrechtgv. 105, p. 159-170, 2011.