Fig. 5. Percent removal of naphthalene (Nap) by a Nap-degrading community in the presence of various 9,10-phenanthrenequinone (PheQ) concentrations. The terms "Sat PheQ," "10% Sat PheQ," and "1% sat PheQ" indicate PheQ concentrations at saturation (4 mg/L), 10% of saturation (0.4 mg/L), and 1% of saturation (0.04 mg/L), respectively. "No PheQ" contained no PheQ, while "sterile control" contained no inoculum. Error bars represent two standard errors.