Chlorophyll a concentration in the Rhine at Bad Honnef
| . | [Chlorophyll a] (μg l−1) . | . | . | ||
|---|---|---|---|---|---|
| Year . | Whole year . | CW 10-20 . | CW 25-35 . | ||
| 1990 | 20.7 | 37.1 | 35.7 | ||
| 1991 | 22.8 | 32.8 | 34.9 | ||
| 1992 | 19.2 | 33.6 | 21.8 | ||
| 1993 | 12.1 | 43.4 | 4.0 | ||
| 1994 | 7.3 | 15.3 | 10.3 | ||
| 1995 | 7.0 | 14.2 | 9.4 | ||
| 1996 | 9.1 | 33.3 | 2.7 | ||
| 1997 | 6.4 | 18.7 | 2.8 | ||
| 1998 | 3.0 | 4.3 | 3.1 | ||
| 1999 | 8.4 | 15.1 | 12.0 | ||
| 2000 | 3.7 | 10.4 | 2.2 | ||
| . | [Chlorophyll a] (μg l−1) . | . | . | ||
|---|---|---|---|---|---|
| Year . | Whole year . | CW 10-20 . | CW 25-35 . | ||
| 1990 | 20.7 | 37.1 | 35.7 | ||
| 1991 | 22.8 | 32.8 | 34.9 | ||
| 1992 | 19.2 | 33.6 | 21.8 | ||
| 1993 | 12.1 | 43.4 | 4.0 | ||
| 1994 | 7.3 | 15.3 | 10.3 | ||
| 1995 | 7.0 | 14.2 | 9.4 | ||
| 1996 | 9.1 | 33.3 | 2.7 | ||
| 1997 | 6.4 | 18.7 | 2.8 | ||
| 1998 | 3.0 | 4.3 | 3.1 | ||
| 1999 | 8.4 | 15.1 | 12.0 | ||
| 2000 | 3.7 | 10.4 | 2.2 | ||
Values are means of whole years and the algal blooms in spring (calendar weeks CW 10-20) and summer (CW 25-35). Data from North Rhine-Westphalia State Environment Agency.