Table 1. OTUs most significantly altered between room temperature and −80°C storage for all samples and each individual.

Sample Origin	OTU ID	Consensus Lineage	p value	Bonferronicorrectedp value	RT mean%	−80°Cmean %
All Samples	5780	Firmicutes;Clostridia;Clostridiales;Lachnospiraceae	0.006	5.951	1.59×10−04	2.44×10−05
	5434	Firmicutes;Clostridia;Clostridiales;Lachnospiraceae	0.010	9.992	1.11×10−04	2.55×10−05
	4167	Firmicutes;Clostridia;Clostridiales	0.014	14.530	1.86×10−04	2.52×10−05
	1710	Bacteroidetes;Bacteroidia;Bacteroidales;Rikenellaceae;Alistipes	0.029	29.303	2.72×10−04	7.03×10−05
	8336	Firmicutes;Clostridia;Clostridiales;Lachnospiraceae	0.032	32.433	2.48×10−04	5.12×10−05
	135	Bacteroidetes;Bacteroidia;Bacteroidales;Bacteroidaceae;Bacteroides	0.033	33.398	1.73×10−05	9.33×10−05
	3326	Firmicutes;Clostridia;Clostridiales;Ruminococcaceae;Faecalibacterium	0.035	35.958	1.79×10−04	5.49×10−05
	6032	Bacteria	0.038	38.225	1.16×10−04	2.70×10−05
	7971	Firmicutes;Clostridia;Clostridiales;Ruminococcaceae;Faecalibacterium	0.039	39.843	2.55×10−05	1.96×10−04
	142	Firmicutes;Clostridia;Clostridiales;Incertae Sedis XIV;Blautia	0.042	42.308	1.89×10−03	2.85×10−03
IBS 1	2064	Bacteroidetes;Bacteroidia;Bacteroidales;Prevotellaceae;Prevotella	0.003	0.387	4.67×10−04	1.94×10−03
	6839	Firmicutes;Clostridia;Clostridiales	0.006	0.799	7.61×10−03	3.18×10−03
	7540	Firmicutes;Clostridia;Clostridiales;Lachnospiraceae	0.027	3.486	1.57×10−02	9.06×10−03
	8513	Firmicutes;Clostridia;Clostridiales;Lachnospiraceae	0.031	3.996	1.82×10−02	1.52×10−02
	7603	Bacteroidetes;Bacteroidia;Bacteroidales;Prevotellaceae;Prevotella	0.042	5.304	8.87×10−04	2.25×10−03
	6717	Firmicutes;Clostridia;Clostridiales	0.051	6.425	8.86×10−04	4.02×10−04
	2944	Bacteroidetes;Bacteroidia;Bacteroidales;Bacteroidaceae;Bacteroides	0.051	6.483	1.02×10−02	6.57×10−03
	3846	Bacteroidetes;Bacteroidia;Bacteroidales;Bacteroidaceae;Bacteroides	0.058	7.373	1.04×10−03	4.19×10−04
	6927	ProteoGammaproteoEnterobacteriales;Enterobacteriaceae;Escherichia/Shigella	0.060	7.682	6.64×10−03	2.16×10−03
	8068	Firmicutes;Clostridia;Clostridiales	0.061	7.693	1.57×10−03	7.12×10−04
IBS 2	5681	Firmicutes;Clostridia;Clostridiales;Eubacteriaceae;Eubacterium	0.002	0.723	4.49×10−04	1.46×10−03
	5276	Firmicutes;Clostridia;Clostridiales;Lachnospiraceae;Dorea	0.003	0.815	1.47×10−04	5.22×10−04
	6589	Firmicutes;Clostridia;Clostridiales;Ruminococcaceae;Oscillibacter	0.006	1.912	2.80×10−02	1.43×10−02
	1971	Firmicutes;Clostridia;Clostridiales;Ruminococcaceae;Faecalibacterium	0.006	1.929	1.14×10−02	5.07×10−03
	6815	Bacteria	0.009	2.685	2.82×10−04	8.56×10−04
	6631	Firmicutes;Clostridia;Clostridiales;Ruminococcaceae;Faecalibacterium	0.011	3.388	1.21×10−03	3.98×10−04
	343	Firmicutes;Clostridia;Clostridiales;Lachnospiraceae	0.013	3.829	2.87×10−04	8.79×10−04
	8906	Firmicutes;Clostridia;Clostridiales;Lachnospiraceae	0.014	4.109	2.25×10−04	7.60×10−04
	9044	Firmicutes;Clostridia;Clostridiales	0.017	5.211	9.61×10−04	3.06×10−03
	6399	Firmicutes;Clostridia;Clostridiales;Incertae Sedis XIV;Blautia	0.022	6.721	7.31×10−04	1.29×10−03
HC 1	452	Firmicutes;Clostridia;Clostridiales;Lachnospiraceae	0.003	0.849	1.57×10−03	9.82×10−04
	3634	Firmicutes;Clostridia;Clostridiales;Lachnospiraceae	0.005	1.636	5.67×10−04	1.95×10−04
	3163	Firmicutes;Clostridia;Clostridiales;Incertae Sedis XIV;Blautia	0.013	4.101	5.69×10−03	3.27×10−03
	809	Firmicutes;Clostridia;Clostridiales;Lachnospiraceae;Roseburia	0.014	4.507	2.36×10−04	5.49×10−04
	9486	ProteoBetaproteoBurkholderiales;Alcaligenaceae;Parasutterella	0.015	4.755	9.26×10−04	1.70×10−03
	6663	Firmicutes;Clostridia;Clostridiales;Ruminococcaceae;Faecalibacterium	0.024	7.418	3.50×10−04	1.53×10−04
	4191	Bacteria	0.026	8.003	1.70×10−03	8.91×10−04
	6951	Firmicutes;Clostridia;Clostridiales;Ruminococcaceae;Faecalibacterium	0.031	9.599	5.31×10−04	2.58×10−04
	3893	Firmicutes;Clostridia;Clostridiales	0.033	10.175	8.86×10−04	1.68×10−03
	7567	Firmicutes;Clostridia;Clostridiales;Incertae Sedis XIV;Blautia	0.039	12.077	4.77×10−04	1.06×10−03
HC 2	5281	Firmicutes;Clostridia;Clostridiales;Ruminococcaceae	0.001	0.259	5.01×10−04	1.63×10−03
	1331	Firmicutes;Clostridia;Clostridiales;Lachnospiraceae	0.004	1.039	1.89×10−04	1.27×10−03
	379	Firmicutes;Clostridia;Clostridiales;Ruminococcaceae;Faecalibacterium	0.006	1.291	2.03×10−03	8.78×10−04
	8605	Firmicutes;Clostridia;Clostridiales	0.008	1.880	4.71×10−04	1.41×10−03
	142	Firmicutes;Clostridia;Clostridiales;Incertae Sedis XIV;Blautia	0.017	3.977	2.92×10−03	4.81×10−03
	3095	Firmicutes;Clostridia;Clostridiales	0.019	4.397	1.68×10−03	3.02×10−03
	331	Firmicutes	0.023	5.269	6.00×10−04	1.46×10−03
	2380	Firmicutes;Clostridia;Clostridiales;Ruminococcaceae;Faecalibacterium	0.023	5.348	1.41×10−03	6.28×10−04
	9034	Firmicutes;Clostridia;Clostridiales;Ruminococcaceae;Faecalibacterium	0.024	5.489	5.86×10−03	3.71×10−03
	9044	Firmicutes;Clostridia;Clostridiales	0.024	5.659	4.21×10−03	6.87×10−03