The Biosphere Control & Management Mr G Davidson

Pollution Pollution occurs when the presence of a substance (the pollutant) in either air, fresh water, sea or land causes harm to organisms, looks unsightly or causes damage to buildings. Pollutants come from three main sources: Agriculture Domestic (home) Industrial waste. 9 December, 2018 G Davidson

Pollution 9 December, 2018 G Davidson

Pollution 9 December, 2018 G Davidson

Controlling Pollution Pollution can have a large impact on land, sea, air or fresh water. It is therefore, essential that some of man’s activities are controlled so that pollution and its effect are reduced. The future of the planet may depend on it. 9 December, 2018 G Davidson

Controlling Pollution Sewage which is a rich source of organic waste is a common pollutant of rivers. Organic wastes can result in considerable changes to the water, and the numbers and kinds of organisms present. Organic waste provides food for micro-organisms (bacteria). 9 December, 2018 G Davidson

Testing River Water for Bacteria If water is polluted by organic waste, such as sewage or paper fibres, bacteria will feed on the organic material, grow and multiply. Like most organisms, bacteria require oxygen which they absorb from the surrounding water. This can cause the death of other aquatic (water living) organisms which require oxygen to survive. 9 December, 2018 G Davidson

Testing River Water for Bacteria Method: ¾ fill a bottle with water from a river or stream. Add 3 or 4 drops of Methylene Blue (This is a blue dye which fades if oxygen is used up.) Add a layer of oil to completely cover the surface. Put the lid on, label the bottle and seal it up. Repeat with other samples. Note the colour of the water after 30 mins, 1 hour, 3 days and 7 days. The quicker it loses its colour the more pollution it has. 9 December, 2018 G Davidson

Pollution Indicators Some animals are only able to live in water which contains a lot of oxygen. Others can survive in water which contains little or no oxygen. In which type of water do you think you would find the following organisms? 9 December, 2018 G Davidson

Stonefly Nymph Unpolluted 9 December, 2018 G Davidson

Water Louse Polluted 9 December, 2018 G Davidson

Caddis Fly Larva Unpolluted 9 December, 2018 G Davidson

Rat-Tailed Maggot Polluted 9 December, 2018 G Davidson

Sludge Worm Polluted 9 December, 2018 G Davidson

Mayfly Nymph Unpolluted 9 December, 2018 G Davidson

Blood worm Polluted 9 December, 2018 G Davidson

Poor Management Man obtains many natural resources from the earth such as coal, oil, timber and food. In his quest for these resources, many ecosystems have been destroyed or disrupted. Since living and non-living resources are finite, man must learn to conserve and manage these resources. 9 December, 2018 G Davidson

Energy & Pollution Most of our electricity comes from power stations which burn fossil fuels (coal or oil). This results in fumes being released into the atmosphere which causes air pollution. In more recent years power stations driven by nuclear reactors have been opened. These reactors produce highly radioactive waste which is difficult to dispose of safely. 9 December, 2018 G Davidson

Farm Management Producing crops and rearing animals on a farm requires the maintenance of an artificial environment. Before the arrival of man most of Scotland was covered in trees. Even now, farm land left uncultivated for a few years will develop scrub and eventually woodland. 9 December, 2018 G Davidson

Farm Management In order to prevent the growth of unwanted plants (weeds) in a field a farmer may use a variety of methods. To produce high yields from his crops a farmer must: Keep the soil fertile – harvesting removes the essential minerals. Prevent wild plants from competing with the crop. Prevent diseases or parasites infecting the crop. 9 December, 2018 G Davidson

Farm Management Until recently the only method of keeping the soil fertile and preventing pests and disease spoiling the crop was to use crop rotation. Crop rotation involves leaving at least 3 years between crops of the same type being grown in the same field. 9 December, 2018 G Davidson

Farm Management This prevents the build up of disease or weed organisms and also allows the level of nutrients for that crop to recover. All rotations should include nitrogen fixing plants such as clover. These increase the level of soil nitrates. 9 December, 2018 G Davidson

Crop Rotation Year 1 potatoes Year 2 Year 4 turnips grass Year 3 clover Year 4 grass 9 December, 2018 G Davidson

Agricultural Chemicals Most farms now use only a simple 2 or 3 year crop rotation. This, along with the use of a variety of chemicals, is sufficient to keep the soil fertile and control weeds and pests. 9 December, 2018 G Davidson

Agricultural Chemicals Chemicals commonly used on the farm are: Inorganic fertilisers which supply nitrates, phosphates and potassium which have been taken up by the crops and lost from the field during harvesting. Insecticides to kill insects. Herbicides to kill weeds. Fungicides to kill fungi, some of which cause disease. 9 December, 2018 G Davidson