Table 4.
Algal species pollution index (Palmer, 1969) in Sidi Abderrahmane reservoir (May 2011-December 2012).
| Indicator species | Pollution index | Sidi Abderrahmane |
|---|---|---|
| Euglena viridis | 6 | − |
| Nitzschia palea | 5 | − |
| Oscillatoria limosa | 4 | + |
| Scenedesmus quadricauda | 4 | − |
| Oscillatoria tenuis | 4 | − |
| Stigeoclonium tenue | 3 | − |
| Synedra ulna | 3 | − |
| Ankistrodesmus falcatus | 3 | − |
| Pandorina morum | 3 | − |
| Oscillatoria chlorina | 2 | − |
| Chlorella vulgaris | 2 | − |
| Arthrospira jenneri | 2 | − |
| Cyclotella meneghiniana | 2 | − |
| Melosira varians | 2 | + |
| Euglena gracilis | 1 | − |
| Nitzschia acicularis | 1 | + |
| Navicula cryptocephala | 1 | − |
| Oscillatoria princeps | 1 | − |
| Oscillatoria putrida | 1 | − |
| Gomphonema parvulum | 1 | − |
| Pollution rating | 5 |
+ Present, − Absent (note that an alga is considered to be present if there are 50 or more individuals per liter.