Practise explaining how sewage entering rivers changes nutrients, decomposer activity, oxygen levels, disease risk and animal biodiversity.
Pollution can occur in the atmosphere and in rivers.
Water pollution can occur if sewage enters a river.
Explain the biological consequences of sewage pollution on a river ecosystem.
An explanation that makes reference to six of the following points:
- pathogenic bacteria / cause disease
- urea / urine / nitrogenous waste / nitrate / phosphate
- decomposition / decomposed / decomposers (ONCE)
- eutrophication / plant growth / algae growth
- (plants) block light / prevents photosynthesis
- respiration (ONCE)
- (less) oxygen ( 1 )
- death of organisms (ONCE) / reduce biodiversity / eq