| Report Year: 2009 |
| Hawthorn Lake (Barnes City Lake), Mahaska County |
| Carbon Balance Table |
| Parameter | 7/20/2009 | 6/16/2009 | 2009 | 2008 | 2007 | 2006 | 2005 | 2004 | 2003 | 2002 | 2001 | 2000 |
| Alkalinity as CaCO3 (mg/L) | 117 | 116 | 116.5 | - | - | - | 134.7 | 113.7 | 81.7 | 95.5 | 98.7 | 172.0 |
| Dissolved Organic Carbon (mM) | 0.39 | 0.38 | 0.39 | - | - | - | 0.51 | 0.33 | 0.81 | 0.69 | - | - |
| Temperature (oC) | 22.9 | 21.2 | 22.0 | - | - | - | 27.0 | 23.2 | 24.9 | 26.6 | 22.8 | 25.2 |
| Specific Conductivity (μS/cm) | 280.0 | 280.0 | 280.00 | - | - | - | 327.88 | 310.92 | 287.44 | 440.13 | 241.85 | 265.80 |
| pH | 8.1 | 7.9 | 8.0 | - | - | - | 8.7 | 8.5 | 8.3 | 8.7 | 8.7 | 8.2 |
| I (Ionic Strength ?) | 0.0490 | 0.0490 | 0.0490 | - | - | - | 0.0574 | 0.0544 | 0.0506 | 0.0904 | 0.0423 | 0.0465 |
| Dissolved Inorganic Carbon (mM) | 2.34 | 2.35 | 2.35 | - | - | - | 2.47 | 2.19 | 1.62 | 1.63 | 1.88 | 3.41 |
| pCO2 (μatm) | 820 | 1357 | 1088.4 | - | - | - | 313.3 | 355.6 | 337.6 | 180.7 | 236.8 | 923.2 |
| Equilibrium CO2 | 13.46 | 14.15 | 13.81 | - | - | - | 11.94 | 13.33 | 13.63 | 11.55 | 13.62 | 12.58 |
| CO2 (μM) | 29.85 | 51.89 | 40.87 | - | - | - | 10.32 | 12.60 | 12.28 | 5.83 | 9.62 | 31.91 |
| Δ CO2 from Equilibrium | 16.386 | 37.738 | 27.06 | - | - | - | -1.62 | -0.74 | -1.35 | -5.72 | -4.01 | 19.33 |