biologyTopic 7 · EcologyPaper 2Grades 8–9
How should a damaged river catchment be restored?
Starting scenario
Upstream nitrate rises from 3 to 11 mg dm⁻³ below farmland. Algal cover rises from 18% to 76%, dissolved oxygen falls from 9.1 to 3.8 mg dm⁻³ and mayfly abundance falls by 82%. A proposed wetland would remove an estimated 55% of nitrate but convert 6 hectares of grassland.
You will work through 8 staged questions that build up the science you need. Then you will answer one big-picture question from memory, with no checklist to help you — and only afterwards will the full connection map be revealed.