Fertilisers are added to the soil to increase its level of what?
Carbon
Nitrate
Oxygen
What effect does harvesting crops have on the nitrate level of the soil?
Decreases
Increases
No change
What is compost an example of?
An artificial fertiliser
A natural fertiliser
A form of soil pollution
Why do natural fertilisers take longer to work when they are added to the soil?
They must be broken down by animals first
They must be broken down by bacteria first
They must be broken down by plants first
What term describes the loss of fertiliser chemicals as water moves through soil?
Accumulation
Denitrification
Leaching
What effect can leached fertiliser have on fresh water?
Increased nutrient concentration
Increased oxygen concentration
Increased pH
The growth of algae in freshwater is normally limited by a low availability of what?
Light
Nutrients
What can cause algal blooms?
An increase in the concentration of dissolved nutrients in a loch
A reduction in the oxygen concentration of a loch
A decrease in the populations of consumers in a loch
What effect can algal blooms have on freshwater?
An increase in the biodiversity of the water
A decrease in the oxygen concentration of the water
An increase in the concentration of dissolved nutrients in the water