Indicator Species/Sampling

Question 1

Indicator species

Answer 1

Organisms that can tell us about the levels of pollution in an area by their presence or absence.

Question 2

Example of indicator species

Answer 2

Lichens can be used as air pollution indicators, especially of the concentration of sulphur dioxide in the atmosphere. Sulphur dioxide can damage lichens and prevent them from growing.

Question 3

Water pollution

Answer 3

Caused by the discharge of harmful substances such as untreated sewage into rivers, lakes and seas.

Question 4

Water pollution example

Answer 4

Many aquatic invertebrate animals cannot survive in the water that has been polluted and resulted in a lowering of oxygen concentration, so their presence or absence indicates the extent to which the body of water is polluted.

Question 5

Kick sampling

Answer 5

A useful method for collecting indicator species invertebrates from shallow waters and one of the key techniques used in monitoring freshwater invertebrates in rivers. (Qualitative technique).

Question 6

Sweep netting

Answer 6

In still water such as a pond, or if the water is too deep to enter safely, sweep netting could be used as a sampling technique instead.

Question 7

Sweep netting technique

Answer 7

Tjis involves standing on the bank of the water and vigorously sweeping a net in the water. They can also be used to collect insects from ling grass and other type of vegetation.

Question 8

Trent Biotic Index

Answer 8

The Trent Biotic Index is an index used to measure the quality of freshwater, based on the diversity and abundance of invertebrates present in a strem or river.

Question 9

Trent Biotic Index technique

Answer 9

The method involves collecting a sample of invertebrates from the area of the stream or river being sampled and then identifying and counting the number of individuals from each of the 10 categories. Categories include pollution sensitive species (mayflies) as well as tolerant species (leeches).

Question 10

Trent Biotic Index calculation

Answer 10

The scores for each category are added together and divided by the total number of individual invertebrates counted to obtain the TBI score. The higher TBI score indicates better water quality, while a lower score indicates poor water quality.