TABLE 1.
Chemical characterization of permafrost filtrates from the Fox Tunnel Permafrost Chronosequence, different letters indicate statistical differences across ages, within a category (P < 0.05). For example, ice content (as % dry weight) was not significantly different between 19 and 33 ka, but 27 ka was significantly different from both 19 and 33 ka.
| Age | 19 ka | 27 ka | 33 ka |
| pH* | 7.730.32a | 7.750.14a | 7.340.09a |
| Ice content** | 39.7210.25a | 121.0514.09b | 51.755.24a |
| Chloride | 649.32169.22a | 95.797.82b | 237.0256.24c |
| Sulfate | 97.1270.48a | 56.108.65a | 165.4874.65a |
| NH4 + | 528.4954.25a | 556.5040.96a | 1815.74136.01b |
| NO3 | 0.630.09a | 1.371.17a | 0.480.08a |
| NO2 | 0.250.14a | 0.610.10b | 0.260.02a |
| δ13C-DOC | −26.20.3a | −26.90.2b | −27.80.1c |
| DOC*** | 74.7020.10a | 124.5025.87a | 181.1337.15b |
| Acetate | 0.910.10a | 7.680.82b | 40.456.89c |
| Butyrate | 0.000.00a | 3.040.57b | 30.156.49c |
| Formate | 0.380.04a | 0.190.01b | 0.340.04a |
| Propionate | 6.001.59a | 0.740.06b | 4.780.85a |
| Isovalerate | 1.270.36a | 1.100.32a | 7.311.56b |
| Glutarate | 0.030.01a | 0.010.00b | 0.030.01a |
| Malate | 0.160.03a | 0.180.04a | 0.260.02b |
| %C*** | 3.141.94a | 3.110.26a | 3.200.39a |
| %N*** | 0.270.16a | 0.210.06a | 0.270.03a |
| C/N*** | 11.811.14a | 15.253.30a | 12.100.98a |
∗Data other than pH, ice content, and δ13C-DOC are in micromoles per liter. DOC (dissolved organic carbon), acetate, butyrate, propionate, isovalerate, glutarate, and malate are reported in millimoles of carbon per liter. All measurements corrected for dilution during measurement. Average values reported as mean ± standard deviation. ∗∗% dry weight. ∗∗∗Data corrected from Mackelprang et al. (2017).