B18.2 Land and water pollution

Question 1

What does an increase in fertilisers do?

Answer 1

The minerals in the fertilisers wash away from the soil into local rivers

Question 2

What are the effects of the high level of nitrates in the river?

Answer 2

These stimulate the growth of algae and water plants - which grow rapidly

Question 3

What are the problems if there is a rapid growth of algae?

Answer 3

Many plants will die due to so much compeition for light

Question 4

What happens if there is an increase in decomposers?

Answer 4

Leads to a fall in the levels of dissolved in oxygen in the sea
Not enough oxygen for fish to survive due to the microorganisms using a lot of oxygen during resperation

Question 5

What does toxic chemicals do to the aquatic fish?

Answer 5

Leads the bioaccumlation effect

Question 6

What is the bioaccumlation effect?

Answer 6

The carnivores eat smaller fish which have some toxic chemicals in their body
As they eat more and more fish it leads to a build of toxic chemicals in their body - as a result they can die

Question 7

What are bioindicaters?

Answer 7

Species such as salmon and bloodworms can only be found in very clean or very polluted water