A field beside a pond is treated with fertiliser. Rain washes some of the fertiliser into the pond. Measurements are taken before the rain and again three weeks later.
| Measurement | Before the rain | Three weeks after the rain |
|---|---|---|
| Dissolved oxygen concentration (mg/L) | 8.2 | 3.1 |
| Number of aquatic animal species recorded | 12 | 5 |
Explain how the change in dissolved oxygen concentration could have caused the change in the number of aquatic animal species recorded.
84 exam-style questions on AQA GCSE Biology 7.3 Biodiversity and the effect of human interaction on ecosystems, covering 7.3.1 Biodiversity, 7.3.2 Waste management, 7.3.3 Land use, 7.3.4 Deforestation, 7.3.5 Global warming, and 7.3.6 Maintaining biodiversity. Each one has a worked solution and a mark scheme showing where the marks go.