Table S2. Read tracking through the DADA2 pipeline										
"Audit note: final/nonchim = 716,915/718,845 = 99.7315%, whereas final/merged = 716,915/766,631 = 93.5150%. Report 99.7% only as retention of nonchimeric reads. Primer-trimming retention is inferred from raw-copy read counts because the exact Cutadapt command/report/version and trimmed FASTQs were not recovered."										
Sample	Group	Type	input	filtered	denoisedF	denoisedR	merged	nonchim	final_length_filtered	pct_retained_of_input (%)
1st_BFP	1st	AMD precipitate-associated biofilm	135001	125825	124817	124748	122825	117659	117603	87.1
1st_BFW1	1st	wall-attached biofilm	121777	112655	111678	111868	109440	101920	100138	82.2
1st_BFW2	1st	wall-attached biofilm	130081	120956	120109	120326	118736	112101	112054	86.1
2nd_BFP	2nd	AMD precipitate-associated biofilm	103679	96564	95795	95868	94441	88404	88397	85.3
2nd_BFW	2nd	wall-attached biofilm	119746	109478	108852	108943	107135	102536	102533	85.6
2nd_wt	2nd	water	123604	115150	114413	114536	113038	104362	104333	84.4
3rd_wt	3rd	water	110429	102684	102045	102191	101016	91863	91857	83.2