Table 3.

Stimulation of methanogenesis and sulfate reduction in enrichments from Elba (E20) and Guaymas Basin (G37 and G50) using different substrates (methanogenesis w/o sulfate).

Substrate	E20	G37	G50
	Methanogenesis
AOM control	+	+	+
No-substrate control	0	0	0
Hydrogen	0	0	0
Formate	0	0	0
Acetate	0	0	0
Methanol	+++	+++	0
Methylamine	+++	+++	0
	Sulfate reduction
AOM control	+	+	+
No-substrate control	0	0	0
Hydrogen	0	++	+++++
Carbon monoxide	0	0	0
Methyl sulfide	0	0	0
Methanol	0	0	0
Acetate	0	0	0
Formate	0	0	0
Propionate	0	0	0

“+”, expected rate measured; “++”, instant rates low, but rates exceed AOM after longer time; “+++”, instant rate low, but rapidly higher than AOM; “+++++”, rate instantly 3 times higher than during AOM; “0”, no rate detectable.