sulfurreducens biofilms, these applied flow rates correspond to shear stresses that were more than three times higher than the highest reported shear stress for EAB erosion in other microfluidic MFCs. After the high-shear flow pulses, a continuous high flow of Qa=Qc=8 mL min -1 (equivalent to 240 mPa) was applied for three minutes, and then the system was allowed to settle under a flow rate of Qa=Qc=0.5 mL h -1 (0.5 mPa) for two days. Upon resumption of measurements across the 25 kΩ external resistor (reduced from 30 kΩ to encourage biofilm regrowth), a non-zero voltage (80 mV) was observed (Figure ). Based on a previous study, we believe that this signal was related to a remaining biofilm seed layer. In that study, the same graphite electrode material was used for microfluidic electrochemical impedance and confirmed a quantity of residual Pseudomonas biofilms following shear erosion of the biofilm outer layers, possibly aided by the electrode surface roughness. The voltage initially recovered to 225 mV approximately one day after the measurements were restarted (t=53 days, marked as phase i in Figure ), followed by a slow recovery over the next 20 days (phase ii), and finally, a steady-state potential of 450 mV was attained (phase iii). It is likely that the initial current increase during phase i was due to the recovery of the biofilm metabolism after re-establishment of the initial co-flow conditions and washout of anolyte and catholyte solutions that may have crossed over to the opposite electrode compartment. The slower recovery in phase ii was likely due to biofilm regrowth from the residual G. sulfurreducens seed layer. When the MFC reached steady state in phase iii (t=61 days), the voltage remained lower than the pre-overshoot voltages (at t=42 days).