Table 3.

Most abundant OTUs and their closely related species found in the uppermost layer of the sediment incubated in laboratory.

Incubation day	OTU No.	Closest relative speciesa	Similarity (%)	Accession No.	Phylum/Classb	Relative abundance (%)c	p-valued	Putative functione
1	43060	Sulfurovum lithotrophicum	98	CP011308	Epsilonproteobacteria	14.4 ± 0.3	<0.001**	SO, NR
	42344	Sulfurimonas autotrophica	92	CP002505	Epsilonproteobacteria	9.7 ± 0.3	<0.001**	Unknown
	25387	Sulfurovum aggregans	96	AB889689	Epsilonproteobacteria	9.2 ± 0.4	<0.001**	SO, NR
	49085	Sulfurimonas sp. 0H30-7C-S	90	AB304903	Epsilonproteobacteria	2.9 ± 0.5	0.002**	Unknown
	27532	Sulfurimonas sp. MA01	95	AB930173	Epsilonproteobacteria	1.6 ± 0.6	0.04*	Unknown
	49878	Desulfobulbus elongatus	92	CP002364	Deltaproteobacteria	1.6 ± 0.0	0.005**	Unknown
	21731	Thiomicrospira psychrophila	100	AJ404732	Gammaproteobacteria	1.2 ± 0.2	0.001**	SO
3	42344	Sulfurimonas autotrophica	92	CP002505	Epsilonproteobacteria	30.7 ± 6.4	0.001**	Unknown
	25387	Sulfurovum aggregans	96	AB889689	Epsilonproteobacteria	9.0 ± 3.4	0.01*	SO, NR
	43060	Sulfurovum lithotrophicum	98	CP011308	Epsilonproteobacteria	8.0 ± 2.1	0.005**	SO, NR
	49085	Sulfurimonas sp. 0H30-7C-S	90	AB304903	Epsilonproteobacteria	4.1 ± 0.8	0.003**	Unknown
	32337	Mariprofundus ferrooxydans	96	EF493244	Zetaproteobacteria	3.9 ± 0.2	<0.001**	FeO
	36501	Thiomicrospira crunogena	100	L40810	Gammaproteobacteria	3.7 ± 0.9	0.002**	SO
	30483	Sulfurimonas denitrificans	98	L40808	Epsilonproteobacteria	2.7 ± 1.1	0.02*	SO, NR
14	45161	Thioalkalispira microaerophila	98	AF481118	Gammaproteobacteria	18.3 ± 1.9	<0.001**	SO, NR
	32337	Mariprofundus ferrooxydans	96	EF493244	Zetaproteobacteria	4.8 ± 0.8	<0.001**	FeO
	6816	Gallionella sp. PN013	97	HQ117915	Betaproteobacteria	4.0 ± 0.2	<0.001**	FeO
	42344	Sulfurimonas autotrophica	92	CP002505	Epsilonproteobacteria	3.9 ± 0.6	0.001**	Unknown
	6961	Dyella ginsengisoli	100	KC129050	Gammaproteobacteria	3.4 ± 2.1	0.05	ChemO
	30483	Sulfurimonas denitrificans	98	L40808	Epsilonproteobacteria	3.1 ± 0.4	<0.001**	SO, NR
	16111	Thiohalophilus thiocyanatoxydans	96	DQ469584	Gammaproteobacteria	2.9 ± 0.5	0.001**	SO, NR
57	45161	Thioalkalispira microaerophila	98	AF481118	Gammaproteobacteria	9.0 ± 1.7	0.001**	SO, NR
	24485	Streptomyces vitaminophilus	99	AB184589	Actinobacteria	8.1 ± 2.5	0.005**	ChemO, NR
	908	Salinispirillum marinum	93	KJ195687	Gammaproteobacteria	5.9 ± 1.7	0.004**	Unknown
	23047	Oleiagrimonas soli	98	JQ658406	Gammaproteobacteria	4.8 ± 1.2	0.002**	ChemO, NR
	30112	Thiohalophilus thiocyanatoxydans	92	DQ469584	Gammaproteobacteria	3.0 ± 1.2	0.01*	Unknown
	45198	Thiohalophilus thiocyanatoxydans	96	DQ469584	Gammaproteobacteria	2.6 ± 0.7	0.003**	SO, NR
	6961	Dyella ginsengisoli	100	KC129050	Gammaproteobacteria	2.4 ± 0.4	0.001**	ChemO

^aThe closely related species were assigned on BLAST in the DDBJ.

^bThe OTUs were characterized phylogenetically by using the QIIME software.

^cThe symbol “±” means the standard deviation of three replications.

^dp-values indicate whether the relative abundance of OTU was significantly high comparing with that in the deep layer:

^*p < 0.05,

^**p < 0.01.

^eThe putative function of closely related species (only sequence similarities >95%). SO, sulfur oxidation; SR, sulfate reduction; FeO, Fe(II) oxidation; ChemO, chemoorganotrophy; NR, nitrate reduction.