Figure F14. Sulfate (SO42-) and methane (CH4) concentration profiles at Site 1247. The sulfate/methane interface (SMI) is defined where a minimum in sulfate concentration and a rapid increase in methane concentration co-occur, which, at this site, is observed at ~11 mbsf. Note the curvature of the sulfate profile at both the top and bottom of the sulfate-reduction zone. The linear portion of the curve between ~6 and 10 mbsf was used to calculate upward methane flux at this site.

Figure F14. Sulfate (SO₄^2-) and methane (CH₄) concentration profiles at Site 1247. The sulfate/methane interface (SMI) is defined where a minimum in sulfate concentration and a rapid increase in methane concentration co-occur, which, at this site, is observed at ~11 mbsf. Note the curvature of the sulfate profile at both the top and bottom of the sulfate-reduction zone. The linear portion of the curve between ~6 and 10 mbsf was used to calculate upward methane flux at this site.