Table 4. Unique and metabolic activity statistics obtained from DuctApe analysis.

Unique metabolic functions (% of wells with ∆ ≥ 1)
	Control	20 kHz	45 kHz	130 kHz	950 kHz
More active	23	31	9	8	5
Less active	5	1	19	3	6
Percentage (%)	7.29	8.33	7.29	2.86	2.86
Metabolic activity statistics (% of active wells with AV ≥2)
Carbon sources	19.27	19.27	7.81	22.91	24.48
Nitrogen sources	25.00	31.25	8.33	18.75	21.87
Phosphorus and sulphur sources	31.25	26.04	18.75	14.58	13.54