Table 1. AMD sample information.

Date	Location	pH	Temperature	Type	Platform	Seq. Data	LII Spacers	LII Groups	LIII Spacers	LIII Groups
Mar 2002	5way	0.83	42.0 °C	MG PCR	Sanger 454	136 MB 52 MB	389991	3516	157	91
Jun 2005	A Drift (UBA)	1.1	41.0 °C	MG	Sanger	114 MB	1871	277	237	187
Jul 2005	A Drift (UBA)	1.23	38.0 °C	PCR	454	13 MB	59764	716	n/a	n/a
Nov 2005	A Drift (UBA)	1.50	38.0 °C	MG	Sanger	106 MB	41	41	48	44
Jun 2006	C Drift (C75)	0.70	43.0 °C	MG	454	80 MB	143	75	0	0
Aug 2006	C Drift (C75)	1.00	43.0 °C	MG	454	88 MB	79	61	0	0
Nov 2006	C Drift (C75)	1.18	42.7 °C	MG	454	90 MB	261	115	8	8
May 2007	C Drift (C75)	1.17	44.4 °C	MG	454	96 MB	304	100	7	7
Aug 2007	C Drift (C75)	1.12	40.2 °C	MG	454	95 MB	232	99	0	0

Abbreviations: AMD, acid mine drainage; n/a, not applicable. Sampling conditions, sequencing information and the number of CRISPR spacers and CRISPR spacer groups recovered from Leptospirillum groups II (LII) and III (LIII) for each AMD biofilm collected for this study. Each line represents a separate sample. ‘Type' refers to the source of the sequencing, either metagenomic dataset (MG) or CRISPR amplicon dataset (PCR). In certain cases, spacers and spacer groups may be shared across multiple samples.