Table 1.
Descriptive statistics for 16 environmental variables measured from 49 forested ponds in southern Indiana, USA.
| variable | mean | s.d. | max. | min. |
|---|---|---|---|---|
| diameter (m) | 17.9 | 6.2 | 32.5 | 7 |
| depth (m) | 1.3 | 0.4 | 2 | 0.3 |
| elevation (m) | 259.3 | 34.1 | 309 | 126 |
| canopy cover (%) | 0.28 | 0.15 | 0.76 | 0.1 |
| temperature (°C) | 22.0 | 1.7 | 25.8 | 18.6 |
| pH | 6.4 | 0.20 | 6.9 | 5.8 |
| dissolved oxygen (mg l−1) | 2.2 | 1.4 | 6 | 0.2 |
| specific conductivity (µS cm−1) | 44.3 | 17.0 | 98 | 12 |
| total dissolved solids (g l−1) | 0.028 | 0.011 | 0.064 | 0.008 |
| colour (a440) | 0.04 | 0.02 | 0.10 | 0.01 |
| oxidative reduction potential (mV) | 146.6 | 58.1 | 326 | 30 |
| dissolved organic carbon (mg l−1) | 9.5 | 2.5 | 18.4 | 5.0 |
| dissolved organic nitrogen (mg l−1) | 0.488 | 0.382 | 1.699 | 0.081 |
| total phosphorus (μg l−1) | 272 | 177 | 737 | 62 |
| chlorophyll a (μg l−1) | 1.8 | 0.5 | 3.4 | 0.7 |