| Report Year: 2009 |
| Arrowhead Lake (Sac), Sac County |
| Phytoplankton |
| | 6/1/2009 | 7/6/2009 | 2009 | 2007 | 2006 | 2005 | 2004 | 2003 | 2002 | 2001 | 2000 |
| Division | Wet Mass (mg/L) | Wet Mass (mg/L) | Wet Mass (mg/L) | Wet Mass (mg/L) | Wet Mass (mg/L) | Wet Mass (mg/L) | Wet Mass (mg/L) | Wet Mass (mg/L) | Wet Mass (mg/L) | Wet Mass (mg/L) | Wet Mass (mg/L) |
| Bacillariophyta | 0.699 | 1.040 | 0.870 | 1.630 | 0.320 | 4.231 | 2.606 | 0.995 | 5.676 | 0.406 | 3.490 |
| Chlorophyta | 0.293 | 1.872 | 1.082 | 2.436 | 0.274 | 0.642 | 0.307 | 0.076 | 0.679 | 0.352 | 0.589 |
| Chrysophyta | 0.000 | 0.000 | 0.000 | 0.000 | 0.000 | 0.000 | 0.000 | 0.000 | 2.297 | 0.000 | 0.000 |
| Cryptophyta | 0.381 | 0.585 | 0.483 | 0.079 | 0.048 | 0.281 | 0.026 | 0.164 | 0.115 | 0.177 | 0.090 |
| Cyanobacteria | 27.981 | 156.041 | 92.011 | 47.552 | 367.427 | 376.009 | 71.836 | 7.118 | 18.920 | 2.135 | 7.701 |
| Dinophyta | 0.000 | 10.818 | 5.409 | 0.000 | 0.156 | 0.509 | 0.112 | 0.228 | 0.296 | 0.440 | 6.119 |
| Euglenophyta | 0.000 | 3.978 | 1.989 | 0.000 | 0.000 | 0.243 | 0.027 | 0.015 | 0.000 | 0.000 | 0.033 |
| Total | 29.354 | 174.335 | 101.844 | 51.696 | 368.226 | 381.915 | 74.914 | 8.595 | 27.983 | 3.509 | 18.022 |
| Taxonomic Richness | 10 | 28 | 19 | 6 | 11 | 13 | 12 | 12 | 10 | 10 | 8 |
| Cyanobacteria Cell Counts(k)/ml | 20.004 | 113.704 | 66.854 | 0.000 | 265.844 | 290.059 | 50.107 | 6.481 | 13.519 | 1.778 | 3.307 |
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