Pollution indicators these show you if an area is polluted or not
lichens = it is made up of a fungus & an algae. the fungus provides stability & structure & traps water but the algae contains chlorophyll that photosynthesises & so makes its own food. there are different types of lichen on trees, walls & stone surfaces.
fresh water shrimps - bacteria use oxygen to decompose organic pollution like sewage or fertilisers in rivers & streams. some fresh water organisms like shrimps can only live in oxygen rich water but others can survive in low oxygen levels. so you can tell how clean or polluted the water is by seeing what shrimp is found in it.
algae - algal bloom in water indicates high levels of organic or inorganic pollution. filamentous (thread like) algae together with fewer planktonic (single celled) algae indicates water that is more acidic.
non living indicators - eutrophication means lots of nitrates dissolved in water causing algal bloom which blocks out light for plants which die so bacteria will use lots of oxygen to break the plants down. therefore, high nitrate levels & low oxygen levels in water are non living indicators of pollution by sewage or fertilisers. high nitrate levels in drinking water can harm babies.
erosion of limestone buildings - burning fossil fuels in power stations or cars may cause acid rain. this cna kill fish & trees & erodes limestone buildings. you get acid rain from : sulphur in the fuel which joins with oxygen in the air to give sulphur dioxide. carbon in fuel combines with oxygen to make carbon dioxide. both these gases dissolve in rainwater to make acid rain.
acid dissolves calcium carbonate (limestone). limestone buildings are gradually eroded by acid rain. you can see this on carvings on buildings or statues. the more erosion, the more sulphur dioxide.

	Created by sfl0404 almost 10 years ago

Note on Biology & our environment, created by sfl0404 on 29/04/2014.

Biology & our environment