TABLE 5.

Rates for sulfate reduction, methanogenesis, and acetate dissimilation in Orange Pond sediments and calculations of the contribution of acetate to methanogenesis and sulfate reduction

Yr of samplinga	Sulfate reduction rate (nmol · cm−3 h−1)b	Methane production rate (nmol · cm−3 h−1)b	Acetate dissimilation rate (nmol · cm−3 h−1)c	poxd	% CH4 from acetatee	% Sulfate reduction from acetate oxidationf
1994	10.99 ± 1.87	3.32 ± 1.21	7.2	0.99	2.00	65.0
1998	6.83 ± 0.82	1.78 ± 0.23	5.6	0.99	3.10	81.2

^aSediments were taken in two separate summer seasons. 

^bValues are means of at least duplicate determinations ± 1 standard deviation. 

^cDetermined from the slopes of the plots (Fig. 4) × 2.303 × acetate pool size. 

^dObtained from Table 3. 

^eBased on the equation CH₃COO⁻ + H⁺ → CH₄ + CO₂ and determined from [nanomoles of acetate per cubic centimeter per hour × (1 − p_ox)/nanomoles of CH₄ per cubic centimeter per hour] × 100. 

^fBased on the equation CH₃COO⁻ + SO₄²⁻ → 2HCO₃⁻ + HS⁻ and determined from (nanomoles of acetate per cubic centimeter per hour × p_ox/nanomoles of sulfate reduced per cubic centimeter per hour) × 100.