Scanning electron micrographs of chalcopyrite surfaces. (A) A. ferrooxidans attached to chalcopyrite after 16 d. (B) Chalcopyrite exposed to A. ferrooxidans for 48 days. The box is magnified in (C). (C) High-magnification image showing the etched appearance of the chalcopyrite surface. (D) A microcolony of cells after 48 days of reaction with chalcopyrite. (E) Chalcopyrite exposed to A. ferrooxidans for 80 days. (F) Rinsed chalcopyrite exposed to A. ferrooxidans for 80 days.