Table 1.
Summary of soil properties at the two study sites in the salt marshes of Spiekeroog Island and Westerhever on the German North Sea coast.
| Site | Spiekeroog | Westerhever | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Salt marsh zone | Pioneer zone | Lower salt marsh | Upper salt marsh | Pioneer zone | Lower salt marsh | Upper salt marsh | |||||
| No. of mean monthly flooding events (10.2014-09.2015) | 46 | 16 | 4 | 20 | 16 | 8 | |||||
| Sediment horizon | Ai | Go/Gr | Ah | Go/Gr | Ah | Go/Gr | Ai | Ah | Go/Gr | Ah | Go/Gr |
| Sand (>63 μm) fraction (%) | 26.0 ± 1.9 | 98.2 ± 0.4 | 22.8 ± 4.9 | 97.5 ± 1.2 | 8.3 ± 1.6 | 92.4 ± 1.2 | 2.9 ± 0.0 | 7.1 ± 2.6 | 9.8 ± 1.8 | 17.7 ± 10.8 | 28.9 ± 5.5 |
| Silt (2-63 μm) fraction (%) | 41.2 ± 3.2 | 1.9 ± 0.4 | 41.6 ± 4.9 | 2.5 ± 1.2 | 54.1 ± 2.4 | 7.6 ± 1.2 | 62.5 ± 0.7 | 64.1 ± 1.9 | 62.4 ± 1.4 | 55.7 ± 4.4 | 49.7 ± 1.8 |
| Clay (< 2 μm) fraction (%) | 32.8 ± 1.4 | 0.0 ± 0.0 | 35.5 ± 5.2 | 0.0 ± 0.0 | 37.6 ± 4.0 | 0.0 ± 0.0 | 34.6 ± 0.7 | 28.8 ± 0.9 | 27.8 ± 0.5 | 26.6 ± 6.4 | 21.5 ± 3.7 |
| Bulk density (g cm−3) | 0.63 ± 0.01 | 1.62 ± 0.01 | 0.60 ± 0.04 | 1.68 ± 0.02 | 0.82 ± 0.08 | 1.63 ± 0.03 | 0.49 ± 0.01 | 0.71 ± 0.10 | NA | 0.62 ± 0.04 | NA |
| pH (H2O) (min-max) | 6.94–7.23 | 7.21–7.80 | 6.45–7.08 | 6.97–7.19 | 7.39–7.72 | 7.07–7.65 | 7.60–8.08 | 7.60–8.20 | 7.50–7.65 | 7.44–7.54 | 7.16–7.4 |
| pH (KCl) (min-max) | 6.87–7.05 | 6.81–7.78 | 6.23–7.23 | 6.48–6.74 | 6.99–7.19 | 6.67–7.39 | 7.07–7.20 | 7.10–7.34 | 7.04–7.19 | 6.92–7.14 | 6.88–7.13 |
| Total nitrogen (%) | 0.40 ± 0.03 | NA | 0.45 ± 0.12 | NA | 0.41 ± 0.08 | NA | 0.44 ± 0.01 | 0.42 ± 0.03 | 0.33 ± 0.03 | 0.33 ± 0.06 | 0.27 ± 0.05 |
| Organic carbon (%) | 3.20 ± 0.74 | NA | 4.40 ± 1.35 | NA | 3.54 ± 0.50 | NA | 5.25 ± 0.07 | 5.06 ± 0.27 | 3.89 ± 0.29 | 4.00 ± 0.69 | 3.24 ± 0.63 |
| C:N ratio of soil | 7.80 ± 1.38 | NA | 9.64 ± 0.37 | NA | 8.99 ± 0.62 | NA | 12.01 ± 0.16 | 12.09 ± 0.30 | 12.00 ± 0.31 | 12.31 ± 0.38 | 11.97 ± 0.54 |
| Na (mg kg−1) | 15, 632 ± 1, 064 | 3, 250 ± 173 | 12, 986 ± 1, 159 | 2, 702 ± 143 | 6, 789 ± 776 | 1, 453 ± 72 | 10, 829 ± 1, 606 | 8, 050 ± 2, 112 | 7, 805 ± 935 | 5, 473 ± 647 | 4, 706 ± 483 |
| S (mg kg−1) | 3, 557 ± 285 | 2, 239 ± 230 | 2, 284 ± 235 | 893 ± 260 | 1, 844 ± 176 | 215 ± 18 | 2, 591 ± 148 | 2, 861 ± 360 | 1, 572 ± 209 | 2, 311 ± 516 | 1, 453 ± 353 |
| Plant-available P (mg kg−1) | 84.46 ± 4.46 | 20.94 | 59.27 ± 6.85 | 59.73 ± 29.84 | 44.83 ± 4.83 | 10.50 ± 1.30 | 224.77 ± 34.37 | 98.47 ± 2.88 | 98.45 ± 5.25 | 94.77 ± 4.66 | 76.33 ± 6.78 |
| Mineral N content (mg kg−1) | 13.91 ± 2.89 | 1.70 ± 1.05 | 17.13 ± 3.40 | 0.88 ± 0.21 | 29.82 ± 4.02 | 1.21 ± 0.08 | 29.06 ± 5.58 | 21.10 ± 2.49 | 9.81 ± 1.14 | 33.64 ± 8.26 | 10.80 ± 5.12 |
Given are means (±SE) of the three saltmarsh zones and the respective soil horizons. Nt and Corg in the Go/Gr horizons of Spiekeroog were close to the limit of quantification and could, thus, not be used for analysis. For statistical comparisons see Supplementary Material 1.
NA, data not available.