Ecosystem function was measured in three north-central PA streams; one impacted by acid mine drainage (Morris Run), one undergoing remediation (Lick Creek), and one non-impacted (Sand Run) during mid-summer 2007. Streams were similar in size, substrata and shade (PAR <1 - 3 mol quanta photons.m^-2.d^-1; mean tree canopy density 87%). pH was < 3.5 in Morris and ~6 in Sand and Lick. Morris had higher sp. conductance and concentrations of SO₄-, dissolved metals, NH₄-N and NO₃-N but lower concentrations of TDP and TP. Ecosystem metabolism was determined using open-system measurements of dissolved O₂ change with reaeration determined from propane evasion. Gross primary productivity (GPP) (all data presented as g O₂.m^-2.d^-1) in Sand, Lick and Morris was 0.400, 0.071 and 1.629, respectively and ecosystem respiration was 3.480, 1.659, and 6.808, respectively. Algal chlorophyll a in Morris (76.6 g/m²) was higher than in Lick (3.09 g/m²) and Sand (4.91 g/m²). Mougeotia dominated the periphyton in Morris whereas diatoms dominated in Lick and Sand. In a PCA analysis that included all metabolic and biologic variables, stream scores did not overlap. Although remediation has restored a more natural periphyton community in Lick, the stream still differs from Sand in some functional aspects.