Measuring abiotic factors in ecosystems

Abiotic Factors

Meteorological equipment can be used to measure weather and climate conditions. Direct chemical tests are used to measure chemical pollutant levels to give us an indication about the concentration of pollutants. Examples of direct chemical tests would include: water tested for PH levels and samples can be assessed for metal ion content e.g. mercury.

Indicator species

Indicator species can also be used to determine the effects of pollution in an ecosystem. Indicator species can be observed by sampling an area to note whether a species is present or not, together with the overall number of a species.  For example certain invertebrates and insect larvae can act as an indicator of water pollution. Oxygen levels in water are reduced by altering the levels of nitrogen compounds caused by pollution when a sewage works outflows into a stream or river. This will have an impact on which species can survive in the stream.

Organisms that can survive in polluted water include: the rat-tailed maggot, the bloodworm, the water louse and the sludge worm. However high levels of pollution will kill off certain species which can’t tolerate low oxygen levels including the mayfly and the stonefly which are sensitive to this type of water pollution, meaning they will not be found when sampling the area if high pollution is detected.  Their presence would therefore indicate clean water.

Air quality can be measured by using lichens as indicator species. Few lichens in an area will indicate a high concentration of sulfur dioxide in the air. Many lichens will indicate a low concentration of sulfur dioxide in the air.

The video below shows an example of an indicator species.