Table S8. Top 30 ASVs: formal SILVA r144 taxonomy and rank-specific bootstrap diagnostics (minBoot=80)																		
ASV_rank	total_reads	pct_of_total	Kingdom	Kingdom_boot	Superphylum	Superphylum_boot	Phylum	Phylum_boot	Class	Class_boot	Order	Order_boot	Family	Family_boot	Genus	Genus_boot	Species	Species_boot
ASV_1	139268	19.43	Bacteria	100	Pseudomonadati	100	Pseudomonadota	100	Gammaproteobacteria	100		47		46		46		46
ASV_2	78022	10.88	Bacteria	100	Pseudomonadati	100	Pseudomonadota	100	Gammaproteobacteria	100	Lysobacterales	100	Rhodanobacteraceae	100	Metallibacterium	100		100
ASV_3	47345	6.6	Bacteria	100	Bacillati	85		60		59		19		12		10		10
ASV_4	41963	5.85	Archaea	100	Methanobacteriati--other	100	Thermoplasmatota	100	Thermoplasmata	100	Thermoplasmatales	100		100		100		100
ASV_5	40883	5.7	Bacteria	100	Pseudomonadati	100	Pseudomonadota	100	Gammaproteobacteria	100	Burkholderiales	85		84		84		84
ASV_6	29432	4.11	Bacteria	100	Pseudomonadati--other	100	Nitrospirota	100	Nitrospiria	100	Leptospirillales	100	Leptospirillaceae	100	Leptospirillum	100		95
ASV_7	20145	2.81	Bacteria	100	Bacillati	100	Bacillota--other	100	Alicyclobacillia	100	Alicyclobacillales	100	Alicyclobacillaceae	100	Acidibacillus--other	100		100
ASV_8	19527	2.72	Bacteria	100	Pseudomonadati--other	100	Nitrospirota	100	Nitrospiria	100	Leptospirillales	100	Leptospirillaceae	100	Leptospirillum	100	ferrooxidans	100
ASV_9	18970	2.65	Bacteria	100	Pseudomonadati	100	Pseudomonadota	100	Gammaproteobacteria	100		71		71		71		71
ASV_10	18869	2.63	Bacteria	100	Pseudomonadati	100	Pseudomonadota	100	Gammaproteobacteria	100		57		48		48		48
ASV_11	15801	2.2	Bacteria	100	Pseudomonadati	100	Pseudomonadota	100	Gammaproteobacteria	100	Lysobacterales	100	Rhodanobacteraceae	100	Metallibacterium	100		100
ASV_12	11999	1.67	Bacteria	100	Pseudomonadati	100	Pseudomonadota	100	Gammaproteobacteria	100	Steroidobacterales--other	100	Steroidobacteraceae--other	100	Acidibacter	100		100
ASV_13	11752	1.64	Archaea	100	Thermoproteati	100	Thermoproteota	100	Nitrososphaeria	100	Group 1.1c	100		100		100		100
ASV_14	11443	1.6	Bacteria	100	Pseudomonadati	100	Pseudomonadota	100	Gammaproteobacteria	100	Lysobacterales	100	Rhodanobacteraceae	100	Metallibacterium	100		100
ASV_15	10709	1.49	Archaea	100	Methanobacteriati--other	100	Thermoplasmatota	100	Thermoplasmata	100	Thermoplasmatales	100	Cuniculiplasmataceae	100	Cuniculiplasma	100		100
ASV_16	10136	1.41	Archaea	100	Methanobacteriati--other	100	Thermoplasmatota	100	Thermoplasmata--other	100		100		100		100		100
ASV_17	6225	0.87	Bacteria	100	Pseudomonadati--other	100	Nitrospirota	100	Nitrospiria	100	Leptospirillales	100	Leptospirillaceae	100	Leptospirillum	100		73
ASV_18	6017	0.84	Bacteria	100	Pseudomonadati--other	100	Acidobacteriota	100	Terriglobia	100	Terriglobales	100	Acidobacteriaceae	100		48		48
ASV_19	5933	0.83	Bacteria	100	Bacillati	100	Actinomycetota	100	Acidimicrobiia	100	Acidimicrobiales	100	Acidimicrobiaceae	100	Aciditerrimonas	100		100
ASV_20	5909	0.82	Bacteria	100		61		43		42		16		6		5		5
ASV_21	5819	0.81	Archaea	100	Methanobacteriati--other	100	Thermoplasmatota	100	Thermoplasmata	100	Thermoplasmatales	100	Cuniculiplasmataceae	90	Cuniculiplasma	90		90
ASV_22	5188	0.72	Bacteria	100	Pseudomonadati	100	Pseudomonadota	100	Gammaproteobacteria	100	Acidithiobacillales	99	Acidithiobacillaceae--other	99	RCP1-48	99		99
ASV_23	4884	0.68	Bacteria	100	Pseudomonadati--other	100	Planctomycetota	100	Phycisphaerae	100	Tepidisphaerales	100	Tepidisphaeraceae	100		100		100
ASV_24	4747	0.66	Bacteria	100	Bacillati	100	Actinomycetota	100	Acidimicrobiia	100	Acidimicrobiales	100	Acidimicrobiaceae	100	Aciditerrimonas	100		100
ASV_25	4565	0.64	Bacteria	100	Pseudomonadati--other	100	Planctomycetota	100	Planctomycetia	100	Isosphaerales	100	Isosphaeraceae	100		50		50
ASV_26	4248	0.59	Bacteria	100	Pseudomonadati	100	Pseudomonadota	100	Gammaproteobacteria	100	Acidithiobacillales	100	Acidithiobacillaceae	100	Acidithiobacillus	100	ferrooxidans	100
ASV_27	4204	0.59	Bacteria	100	Pseudomonadati--other	100	Planctomycetota	100	Phycisphaerae	100	Tepidisphaerales	100	Tepidisphaeraceae	100		100		100
ASV_28	3515	0.49	Bacteria	100	Bacillati	100	Actinomycetota	100	Acidimicrobiia	100	Acidimicrobiales	100	Acidimicrobiaceae	100	Ferrithrix	96		96
ASV_29	3345	0.47	Bacteria	100	Pseudomonadati	100	Pseudomonadota	100	Alphaproteobacteria	100	Rhodospirillales	100	Acetobacteraceae	100	Acidiphilium	100	angustum	97
ASV_30	3338	0.47	Bacteria	100	Bacillati	100	Bacillota--other	100	Alicyclobacillia	100	Alicyclobacillales	100	Alicyclobacillaceae	100	Acidibacillus--other	100		100