Fertilisers and eutrophication

Question 1

How are nutrients lost in crops?

Answer 1

Crops are harvested so they don’t die and decompose in there, meaning mineral ions are not returned to the sold by decomposers. Animals are also move so the nutrients are not replaced through their remains or waste products

Question 2

What are fertilisers used for?

Answer 2

To replace lost minerals so more energy from the ecosystem can be used for growth, increasing the efficiency of energy transfer

Question 3

What are artificial fertilisers?

Answer 3

Inorganic fertilisers that contain pure chemicals

Question 4

What are natural fertilisers?

Answer 4

Organic matter that include things like manure, composted veg, crop residues and sewage sludge

Question 5

What is the environmental issue with fertilisers?

Answer 5

Excess fertilisers can leach into waterways and lead to eutrophication

Question 6

What is leaching?

Answer 6

When water soluble compounds in soil are washed away

Question 7

Explain the process of eutrophication

Answer 7

1. Mineral ions leached from fertilised fields stimulate rapid growth of algae in water
2. This increases the amount of algae which blocks light from reaching plants below
3. Plants die as they are unable to photosynthesise enough
4. Bacteria feed on dead plant matter. This increases the number of bacteria and decreases in the oxygen concentration in water by carrying out aerobic respiration
5. Fish and other aquatic organisms die as there isn’t enough dissolved oxygen