The diagram shows a river running from the mountains towards the sea. Trees are felled and cleared from the shaded area. After a rainstorm, what effect does this have on the nitrate ion content at X and at Y?
- Anitrate ion content at X increases; nitrate ion content at Y increases
- Bnitrate ion content at X increases; nitrate ion content at Y decreases
- Cnitrate ion content at X decreases; nitrate ion content at Y increases
- Dnitrate ion content at X decreases; nitrate ion content at Y decreases