Ecologists in Yorkshire investigated the decomposition of oak leaf litter. They placed bags containing oak leaves on the forest floor. The initial dry mass of oak leaves in each bag was 45.0 g. The bags had two different mesh sizes: 0.5 mm (which excludes soil invertebrates but allows fungi and bacteria) and 5.0 mm (which allows both soil invertebrates and microorganisms).
At 8-week intervals, bags were retrieved, and the dry mass of the remaining leaf litter was measured.
The data collected are shown in the table below:
| Time (weeks) | Dry mass of leaf litter remaining in 0.5 mm mesh (g) | Dry mass of leaf litter remaining in 5.0 mm mesh (g) |
|---|---|---|
| 0 | 45.0 | 45.0 |
| 8 | 41.4 | 38.7 |
| 16 | 37.8 | 31.5 |
| 24 | 34.2 | 25.2 |
| 32 | 31.5 | 18.9 |
Calculate the percentage decrease in the dry mass of the oak leaves in the 5.0 mm mesh bag by week 32.
