Table 2. Characteristics of metagenomes.

Layer	0–10 cm	10–20 cm	20–30 cm	30–40 cm
Pre-QC sequences	185,235	216,879	138,794	126,219
failed QC	56,865	57,809	48,030	47,123
Post-QC sequences	128,370	159,070	90,764	79,096
known proteins	71,640	88,712	44,269	44,190
unknown proteins	55,850	68,547	40,959	34,071
rRNA	688	900	5,536	534
other	192	911	0	301
Post-QC length (bp)	450±90	459±84	429±118	448±96
G+C (%)	57±9	53±11	53±10	52±11