Figure 2

Box plot of abundance of AOA-amoA gene and AOB-amoA gene in soil samples treated with combined EFX and Cu for 21 days (Different letters a/b/c/d/e/f and A/B/C/D/E/F in columns are significantly different at P < 0.05 level between treatments on AOA-amoA gene and AOB-amoA gene respectively).