20.Human influences on Ecosystems Flashcards
Part 2:Pollution and Conservation
1
Q
Describe the effects of :
a) Untreated sewage on aquatic ecosystems
A
- Provides a good source of food for bacteria and they reproduce rapidly
- Bacteria respire aerobically and deplete oxygen
- Aquatic organisms such as fish die of suffocation-Eutrophication
2
Q
b) Fertilisers on aquatic ecosystems
A
- Causes rapid growth of algae which then die
- Decomposing bacteria feed on algae
- Oxygen is depleted and aquatic organisms die-Eutrophication
3
Q
c)Heavy metals
A
Heavy metals do not break down and so bioaccumulate in food chains
This cause food poisoning to top carnivores.
4
Q
A