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Pollution indicators - Higher

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Explainer Video

Tutor: Holly

Summary

Pollution indicators

In a nutshell

Living organisms are all adapted to live in different conditions. Some organisms are well adapted to living in polluted conditions. Their presence or absence can give an indication of the pollution level. The impact of human activity on a habitat can be studied using these organisms. These organisms are known as indicator species.

Water pollution

Water can become polluted by fertilisers or sewage. This pollution can cause eutrophication which will decrease the concentration of oxygen in the water. The types of living organism that are found in the water will depend on the level of pollution.

Pollution level	Organisms present
Polluted water	Blood worms and sludgeworms are adapted to live in low oxygen environments. Therefore, these will be found in polluted water.
Clean water	Stonefly larvae, freshwater shrimps and mayflies will be found in clean water. They are very sensitive to oxygen concentrations so they would not survive in polluted water. Therefore, their presence indicates clean water.

Air pollution

The air can become polluted in a variety of different ways, like sulphur dioxide being released from power stations and car exhausts.

Lichen

Lichen is a symbiotic relationship between a fungus and algae or cyanobacteria. Lichen is sensitive to sulphur dioxide concentrations so the type of lichen that grows will indicate the level of pollution in the area.

Type of lichen present	Explanation
Bushy	Bushy lichen can only survive in unpolluted areas so these indicate very clean air.
Leafy	Leafy lichen can survive in environments with a small amount of pollution so these indicate clean air.
Crusty	Crusty lichen can survive in polluted environments so the presence of only these will indicate polluted air.

Blackspot fungus

Blackspot fungus grows on the leaves of rose plants. The fungus is damaged by sulphur dioxide so in areas of high air pollution, the fungus can not grow. This means that in polluted areas, the leaves of the roses will not have blackspot fungus.

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Unit 1

Photosynthesis and plant adaptations

Unit 2

Ecosystems and interdependence

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