TABLE 1.
Summary of geochemical characteristics of soils and pore waters and rates of CH4 production and SO42− reduction measured in WCA soilsa
| Site | Coordinates | Soil chemistryb |
Pore water chemistryc |
CH4 production rate (μmol · g soil−1 · day−1)e |
SO42− reduction rate (μmol · g soil−1 · day−1)e |
||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| TP concn (g/kg) | TN concn (g/kg) | TC concn (g/kg) | Acetate concn (μM) | H2 concn (μM) | SO42− concn (μM)d | Intact soils | Acetate | H2-CO2 | Intact soils | Acetate | H2-CO2 | ||
| F1 | 26°21′39″N, 80°22′10″W | 1.28 ± 0.24 | 31 ± 3 | 442 ± 31 | 19.5 ± 9.9 | 0.33 ± 0.10 | 56 ± 86 | 3.1 ± 3.2 | 5.3 ± 1.4 | 11.6 ± 3.5 | 0.5 ± 0.4 | 1.4 ± 0.3 | 1.2 ± 1.0 |
| F4 | 26°18′59″N, 80°23′01″W | 0.59 ± 0.26 | 34 ± 3 | 424 ± 29 | 25.9 ± 33.8 | 0.28 ± 0.20 | 74 ± 110 | 0.9 ± 0.9 | 2.7 ± 0.5 | 5.6 ± 2.9 | <0.01 | 0.1 ± 0.1 | <0.01 |
| U3 | 26°17′15″N, 80°24′41″W | 0.25 ± 0.04 | 27 ± 5 | 385 ± 69 | 17.1 ± 16.4 | 0.28 ± 0.14 | 39 ± 35 | <0.1 | 0.4 ± 1.2 | 2.1 ± 1.0 | 0.03 ± 0.04 | 0.07 ± 0.07 | 0.14 ± 0.17 |
| W3 | 26°02′35″N, 80°49′39″W | 0.38 ± 0.02 | 36 ± 1 | 424 ± 4 | NDf | ND | ≤4 | ND | ND | ND | ND | ND | ND |
Data represent means ± SDs.
Soil chemistry in topsoils (0 to 4 cm) sampled in April 2010 and August and December 2012 from the WCA-2A sites (n = 9 from triplicates of each sample) and February 2012 and April 2013 from site W3 (n = 6) was assayed.
Acetate and H2 concentrations were measured in pore waters (0 to 4 cm) sampled in April 2010 and August 2011 (n = 6).
SO42− concentrations for sites F1, U3, and W3 were adapted from our previous study (52), with additional data for samples from site F4 collected in April 2010 and August and December 2012 (n = 9) being analyzed in this study.
The rates of methane production and SO42− reduction were measured in incubations with soils (depth, 0 to 4 cm) sampled in August 2012. Acetate (4 mM) and H2-CO2 (50 kPa) were added in triplicate.
ND, not determined.