Fig. 7 Activity of M91-3 in atrazine- and glucose-containing medium (without NO^-₃) in a sand-column microcosm with reduced conditions in the bottom zone (Experiment VI). Na₂S (0.5 mL of 2.5% Na₂S·9H₂O) was added through Port 5 at the beginning of the experiment. (A) atrazine concentration, (B) redox potential, and (C) pH