Table 2. Characteristics of composite genomes reconstructed from the RSF metagenomes.

ID	Phylogenetic affiliationa	No. of contigs	Genetic size (Mb)	N50	GC (%)	Average sequencing depth	No. of genes	No. of single-copy genesb	No. of multiple single-copy genes	Relative abundance (%) TOP/BULK
CG7	Methylococcaceae	790	3.6	9864	48	14	3883	104/105	5	0.94/0.40
CG10	Acidobacteria subdivision 4	268	4.2	66 255	52	41	4015	104/106	4	2.45/2.43
CG5	Betaproteobacteria	1228	4.4	17 803	65	22	4938	104/106	13	0.45/2.13
CG1	Bacteria	897	5.6	25 218	69	18	5009	101/105	2	0.55/2.30
CG3	Rhizobiales	528	3.7	18 144	64	16	3754	99/105	3	1.14/1.44
CG33	Gemmatimonadetes	1567	4.5	8048	67	21	5141	96/104	8	0.30/1.91
CG2	Bacteria	868	2.8	4962	63	10	3062	91/105	3	0.14/0.57
CG13	Burkholderiales	540	5.1	19 632	68	15	5132	90/106	1	1.68/1.64
CG6	Alphaproteobacteria	871	2.0	3722	39	8	2502	88/105	4	0.21/0.06
CG4	Planctomycetaceae	1632	6.3	7253	62	10	6136	87/102	7	0.43/1.36
CG26	Nitrosomonas	1728	3.3	4142	43	10	4378	81/106	14	0.33/0.04
CG18	Sphingomonas	873	3.1	11 151	61	17	3666	80/105	6	0.91/0.53
CG24c	Nitrospira	17 640	22.4	2136	56	70	33 880	105/105	102	29.59/9.57
CG15c	Acidobacteria	2078	10.0	55 629	65	27	10 572	103/105	98	0.70/5.37

Abbreviation: RSF, rapid sand filter.

^aA taxon was assigned when at least 75% of the identified essential single-copy genes resulted in a concordant taxonomy.

^bThe number is given in relation to the average number of essential genes in all sequenced finished genomes in the given phylum (Albertsen et al., 2013).

^cRepresent multiple genomes from the same clade.