Table 2. Analytical methods and estimated errors.

Analyte		Method	Accuracy	Ref.
Fluid	pH	pH meter	± 0.02	[33]
	Alkalinity	potentiometric titration	± 0.02 mM	[33]
	Si	colorimetric (molybdenum blue)	± 8%	[33]
	Na+, K+, Mg2+, Ca2+	ICP-OES	± 5%
	NH4+	colorimetric (indophenol)	± 8%	[33]
	Cl−, Br−, SO42−	ion chromatography	± 5%
	NO3−	HPLC	± 5%	[34]
	H2S	precipitated as BaSO4 from HgS, gravimetric	± 5%	[35]
	CH4	GC-HID	± 10%
Sediment, Chimney, POM	TOC, TN	EA (flush combusion method)	± 5%
	AVS	precipptated as BaSO4 from CdS, gravimetric	± 5%	[36]
Isotopic Ratio	δ13C of CH4	CF-irMS	± 0.3%	[37]
	δ13C, δ18O of carbonate	irMS with dual inlet	± 0.06‰
	δ13C, δ15N of sediment, chimney, POM, animal	CF-irMS	± 0.2, ± 0.3‰
	All of δ34S	precipitate as BaSO4, CF-irMS	± 0.3‰