Using δ15N of periphyton and fish to evaluate spatial and seasonal variation of anthropogenic nitrogen inputs in a polluted Brazilian river basin - Carvalho, Débora Reis de; Alves, Carlos Bernardo Mascarenhas; Flecker, Alexander S.; Sparks, Jed P.; Moreira, Marcelo Zacharias; Pompeu, Paulo Santos (Ecological Indicators, 2020)