Table 1.

The experimental setup, qPCR results and microbial community characteristics.

Experiment name1	Amendments		Incubation time	16S rRNA gene copy nr mL-1	dsrB gene copy nr mL-1	DGGE band affiliations	Most abundant OTUs from amplicon sequencing
	acetate	${\mathrm{S}\mathrm{O}}_{\mathrm{4}}^{\mathrm{2}\mathrm{-}}$
Acetate	+	-	4	1,48E+03	3,69E+02	Dehalobacter. Desulfurella. unresolved	Dethiobacter (31%)
Acetate	+	-	32	6,13E+04	5,36E+02	Pseudomonadaceae. Mollicutes. Caulobacteraceae	Dethiobacter (32%)
Acetate	+	-	68	7,83E+04	3,88E+02	Caulobacter. Pseudomonadaceae	Brevundimonas (72%)
Ac + ${\mathrm{S}\mathrm{O}}_{\mathrm{4}}^{\mathrm{2}\mathrm{-}}$	+	+	4	2,31E+03	2,82E+02	Dethiosulfatibacter. Sulfobacillus. Desulfurella. Mollicutes	Dethiobacter (29%)
Ac + ${\mathrm{S}\mathrm{O}}_{\mathrm{4}}^{\mathrm{2}\mathrm{-}}$	+	+	32	3,29E+03	4,49E+02	Caulobacter. Desulfurella. Novosphingobium	Dethiobacter (28%)
Ac + ${\mathrm{S}\mathrm{O}}_{\mathrm{4}}^{\mathrm{2}\mathrm{-}}$	+	+	68	1,01E+06	3,12E+03	Rhizobium. Cellulomonas. Stenotrophomonas	Rhizobium (39%)
${\mathrm{S}\mathrm{O}}_{\mathrm{4}}^{\mathrm{2}\mathrm{-}}$	-	+	4	3,91E+03	4,79E+01	Desulfurella. Mollicutes	Dethiobacter (40%)
${\mathrm{S}\mathrm{O}}_{\mathrm{4}}^{\mathrm{2}\mathrm{-}}$	-	+	32	2,13E+04	nd	Desulfurella. Mollicutes	Dethiobacter (31%)
${\mathrm{S}\mathrm{O}}_{\mathrm{4}}^{\mathrm{2}\mathrm{-}}$	-	+	68	2,91E+04	5,96E+03	Pseudomonadaceae. Agrobacterium. Sulfobacillus. Desulfurella	Novosphingobium (14%) Nocardioides (14%)
Ctrl-H2O	-	-	4	2,38E+03	5,38E+01	Desulfurella. Mollicutes. Desulfotomaculum	Dethiobacter (33%)
Ctrl-H2O	-	-	32	2,52E+03	1,66E+02	Mollicutes	Dethiobacter (31%)
Ctrl-H2O	-	-	68	7,24E+04	2,95E+02	Agrobacterium. Arthrobacterium. Cellulomonas	Cellulomonas (41%)
Ctrl-fracture1	-	-	0	5,59E+02	3,24E+02	Mollicutes. Desulfurella, sequences affiliating with plastids	Unclassified Chloroplast (77%) Dethiobacter (10%)

¹All experiments were done in microcosms except Ctrl-fracture, which represents sample from the intrinsic fracture fluid. nd, not detected.