Table 2.

Onset times when a significant pH change was first detected in individual experiments, along with the estimated propagation rate of the observed pH front and measured average currents. The propagation rate estimates were made by comparing the positions of the front in consecutive time points. Currents recorded at a period of 62.5 ms by the High Voltage Sequencer were averaged over time and their 95% confidence intervals over 10 minutes were calculated.

	σ=0.01 S/m			σ=0.05 S/m			σ=0.10 S/m
	Onset time	Est. propagation rate (μm/s)	Avg. current (μA)	Onset time	Est. propagation rate (μm/s)	Avg. current (μA)	Onset time	Est. propagation rate (μm/s)	Avg. current (μA)
100 V/cm	t = 6 min	31	2.5±0.01	t = 4 min	29	1.3±0.03	N/O	N/A	1.9±0.01
	t = 8 min	22	2.3±0.01	t = 9 min	33	2.7±0.01	N/O	N/A	0.39±0.01
	t = 4 min	110	1.7±0.01	t = 9 min	26	3.0±0.01	N/O	N/A	1.3±0.01
	t = 3 min	31	2.5±0.01	N/O	N/A	1.8±0.01	N/O	N/A	3.9±0.01
	t = 9 min	19	2.0±0.01	N/O	N/A	3.1±0.01
				N/O	N/A	3.0±0.01
3000 V/cm	t = 0 min	115	27.2±0.45				t = 0 min	115	31.5±0.37
	t = 0 min	115	36.6±0.42		N/C		t = 0 min	115	42.7±0.72
	t = 0 min	115	21.6±0.18				t = 0 min	>115	27.2±+0.14

N/O is not observed, N/C is not conducted, and N/A is not applicable.