The use of indicator species – Higher
Pollution indicators
The level of pollution in air or water can be indicated by the species living there. This is known as an The presence, abundance or absence of these organisms provides information such as the level of pollution in the environment.. Data obtained using indicator species will only show if an area is polluted or not. Indicator species cannot measure pollution levels only chemical analysis using electronic meters and laboratory tests can do this.
Species that indicate water pollution levels
If water is polluted by raw sewage or fertilisers, 'Hyper-nutrition' resulting from fertiliser pollution of aquatic ecosystems. can happen, which decreases the oxygen concentration in the river or lake. Some freshwater animals are very sensitive to the oxygen levels such as stonefly larvae and freshwater shrimps. If these animals are found in a river, it shows that the river is clean. However, some animals are adapted for surviving in polluted conditions and can survive in low oxygen concentrations. Examples are blood worms and sludge worms. The presence of these species indicates there is a high level of water pollution.
Species that indicate air pollution
Pollutants in the air such as sulfur dioxide are released from power stations. Air pollution can be monitored by indicator species. Some species of A type of fungus that grows on rock. and blackspot fungus are very sensitive to sulfur dioxide, if there are very high levels in the air then they will not be able to grow. By looking at the number and type of lichens present in various locations, scientists can determine how clean or how polluted the air is.
Image caption, Bushy lichens need really clean air
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