Fig. 6 Activity of M91-3 in atrazine-, glucose-, and NO^-₃–containing medium in a sand-column microcosm with reduced conditions in the bottom zone (Experiment V). 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, (C) NO^-₃ concentration, (D) NO^-₂ concentration, and (E) pH