Table 3. Relative abundance (%) and total number of sequences matching genes from various anaerobic respiratory pathways.

Layer	Denitrifi-cation	Sulfatereduction	Arsenate reduction	10-heme cytoa	DMSOb reduction	TMAOcreduction	Dehalo-respd
0–10 cm (%)	0.027	0.012	0.016	0.026	0.009	0.007	0.002
10–20 cm (%)	0.030	0.029	0.019	0.019	0.008	0.008	0.001
20–30 cm (%)	0.017	0.014	0.026	0.014	0.012	0.014	0.004
30–40 cm (%)	0.046	0.023	0.015	0.010	0.018	0.009	0.000
Mean (se) (%)	0.030 (0.006)	0.019 (0.004)	0.019 (0.003)	0.018 (0.003)	0.012 (0.002)	0.010 (0.002)	0.002 (0.001)
total seqs	134	92	86	84	49	42	7
Pearson χ2 (P)	12.26 (0.007)	12.42 (0.006)	4.15 (0.246)	6.92 (0.074)	4.14 (0.247)	6.36 (0.096)	3.50 (0.321)

^a-10-heme cyto = decaheme cytochromes.

^b-DMSO = dimethylsulfoxide.

^c-TMAO = trimethylamine N-oxide.

^d-Dehaloresp = dehalorespiration.