Fig. 1. (a) Net rates of NO and N₂O production under anaerobic (0.5–27 h), partially aerobic (27–51 h), and restored anaerobic (51–72 h) conditions. Error bars indicate standard errors , and those not shown were smaller than the symbols. (b) Net rates of NO and N₂O production in the anaerobic reference column that was maintained under anaerobic conditions for the entire 72 h