The respiration by bacteria using oxygen is
aerobic
 anaerobic
Algae use the nitrates to
make proteins
 make lipids
 make carbohydrates
 to make ammonia
Macrophytes (large plants) die because of lack of light for

 

Nutrients can also come from sewage inputs. Follow the link for questions on sewage pollution.

 

 

 

 

To find out more about water quality in Britain visit the web site of the Environment Agency, the government organisation that monitors pollution. http://www.environment-agency.gov.uk/

 

 

 

 

 

 

 

 

 

 

 

These stonefly nymphs where found in the stream.

 

Which of the following statements will not be true.
The water is well oxygenated.
 The stream is fast flowing.
 The stream is very eutrophic.
 There may be trout in the stream.

 

Problems with fertilisers

Leaching.

If the nutrients in fertilisers are not taken up by plants their is a danger that they will be washed out of the soil by rain water and that the run off will enter stream and rivers. This process is could leaching. The problem with this is that it may cause eutrophication.

Eutrophication.

This is the process that takes place when freshwater is 'enriched' by nutrients, especially nitrates and phosphates.

Eutrophic streams like these get inputs of nitrates and phosphates from fertilisers spread on the surrounding fields.

Some invertebrates are better adapted to survive low oxygen levels. The water quality can be assessed by looking at the invertebrates present.

Stonefly nymphs need well oxygenated water. Chironomid (non-biting midge) larvae can tolerate low oxygen levels.

Sampling a stream for invertebrates to assess water quality.