Table 1. Mock communities sequenced.

Library name	Composition	Reads obtained	Reads used for analysis	Number of extra OTUs	Number of extra OTUs without singletons
Mock 1a	Equal number of 16S rRNA molecules for seven species	6471	4004	0	0
Mock 1b	Equal number of 16S rRNA molecules for seven species	6833	4239	1	1
Mock 2a	Equal number of cells for seven species	6131	3778	0	0
Mock 2b	Equal number of cells for seven species	6186	4222	12	4
Mock 3a	Unequal number of cells for seven species	5607	3778	3	1
Mock 3b	Unequal number of cells for seven species	5132	3268	0	0

OTU, operational taxonomic unit.