YOU ARE LEARNING:
Eutrophication can occur due to human agricultural activities. It affects bodies of water and decreases the health of ecosystems there.
This lesson looks at eutrophication and its effects on biodiversity.
What do you think eutrophication actually means?
What do you think is the primary cause of this increase of nutrients in ecosystems?
So which ecosystem is mainly affected by eutrophication?
What causes these fertilisers to end up in lakes and rivers?
What do we call it when fertilisers are washed off the land?
What is the general definition for leaching?
Leaching of fertilisers leads to eutrophication of rivers and lakes.
Why is eutrophication a problem?
How can increased amounts of algae threaten the ecosystem, for example in a river?
Growth of algae kills plants in the rivers. When plants die, what is the primary problem for the ecosystem?
Therefore, what is the end effect of eutrophication?
Eutrophication stimulates growth of algae that form a layer on the lakes and rivers. This surface layer blocks sunlight from reaching the plants in the water, and the plants will eventually die. When they are dead, the plants will be broken down, and that process uses up the remaining oxygen in the water. When there is no oxygen left in the water, all organisms (plants and animals) will have died.