Fig. 7. Morphology assessment. Scanning electron micrographs of S. oneidensis MR-1 from Passage D exposed to (a) no nanoparticle or ions over 4 passages, (b) 25 mg L^–1 NMC over 4 passages (c) 25 mg L^–1 NMC ion eq. over 4 passages (d) no nanoparticle or ions for one passage, (e) 25 mg L^–1 NMC over 2 passages followed by 2 passages without exposure, (f) 25 mg L^–1 NMC ion eq. over 2 passages followed by 2 passages without exposure. Table indicates mean, median, and standard deviation in μm for the imaged microbe populations. Statistical analyses to compare the lengths of the bacteria are included in the ESI (Fig. S12).† .