| Year | Total biomass t (dw) | Phosphorus (t) | Nitrogen (t) |
| 1997 | 268 | 0.9 | 7.4 |
| 1998 | 213 | 0.7 | 6.3 |
| 1999 | 432 | 0.8 | 7.8 |
| 2000 | 343 | 0.9 | 6.6 |
| 2001 | 740 | 1.2 | 9.8 |
| 2002 | 817 | 1.2 | 9.8 |
| 2003 | 140 | 0.3 | 2.7 |
| 2004 | 698 | 1.1 | 10.5 |