Table 1.
Depth dependent solid phase S, Fe, and C analyses reporting mean values with one standard deviation.
| Depth (m) | Bioavailable Fe (μmol/g) | Total Fe (μmol/g) | OrgC [%) | AVS (μmol/g) | AES μmol/g) | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| Mean | ± | Mean | ± | Mean | ± | Mean | ± | Mean | ± | |
| 2–4 | 22.58 | 0.45 | 35.89 | 0.24 | 0.79 | 0.16 | 0.43 | 0.00 | 0.01 | 0.00 |
| 6–8 | 25.79 | 0.43 | 39.67 | 1.25 | 0.75 | 0.09 | 0.53 | 0.00 | 0.01 | 0.00 |
| 14–16 | 27.73 | 1.41 | 41.26 | 0.64 | 0.87 | 0.12 | 0.51 | 0.01 | 0.01 | 0.00 |
| 22–24 | 38.18 | 0.40 | 62.30 | 0.57 | 0.94 | 0.04 | 0.49 | 0.04 | 0.01 | 0.00 |
| 32–34 | 47.24 | 0.93 | 73.39 | 1.05 | 1.22 | 0.01 | 0.43 | 0.01 | 0.01 | 0.00 |
Means were generated based on triplicate analyses with one standard deviation (SD) of variation. Bioaccessible Fe [i.e., Fe(III)] for IRB was quantified as the Σ of sequential extraction steps 2 and 3 (amorphous and crystalline Fe oxides, Haack and Warren, 2003), Total Fe, Σ of Fe extracted in all 6 extraction steps.