Human Influencences Flashcards
Source + effects of carbon monoxide
source: incomplete combustion of fossil fuels in motor vehicle engines
effects: poisonous gas, prevents haemoglobin from being able to pick up oxygen and transport it around the body for respiration by the tissues
Sources + effects of sulphur dioxide
source: combustion of fossil fuels that contain sulphite based impurities
effects: acid rain
Acid rain cycle
- burning fossil fuels gives of sulphur dioxide + nitrogen oxides
- acidic gases are spread by the wind and dissolved in rain and snow
- sulphur dioxide combined with water to form sulphuric acid
- nitrogen oxides combine with water to form nitric acid
plants, rivers, lakes and animals are harmed by acid rain
How do human activities contribute to greenhouse gases + effect?
- the human production of CO2 (burning of fossil fuels), methane and water vapour - green house gases
- some infrared radiation from the sun passes through the atmosphere, but most is absorbed and re-emitted in all directions by green house gas molecules -> enhanced green house effect -> global warming
Effects of global warming
- temperature rises
- water shortages
- increased fire threat
- Extreme weather -> storms, hurricane etc.
- rising sea level
Melting glaciers + warming oceans
Greenhouse gases
Water vapour, carbon dioxide, nitrous oxide, methane and CFCs
Biological consequences of pollution of water by sewage
- pollution by sewage causes eutrophication
- sewage contains lots of phosphates from detergents e.g. washing powder. It also contains nitrates from urine and faeces
Biological consequences of eutrophication by fertiliser
- fertilisers added to soil but are very soluble so get washed out of soil and intro rivers + streams -> leaching
- due to the excessive nutrients, algae and aquatic plants start to grow rapidly
- the algae covers the surface of the water and blocks sunlight from entering
- plants die and start to decompose
- decomposing bacteria in the water multiply rapidly + use oxygen in the water for respiration
- the oxygen content of the water falls
- fish die
Effects of deforestation on carbon cycle
- forests act as a major store of carbon as they take carbon dioxide from the atmosphere for photosynthesis
- fewer trees mean less co2 is taken from the atmosphere during photosynthesis and less oxygen is given out. The increased levels of co2 contributed to enhanced greenhouse effect
Effects of evapotranspiration on the water cycle
- trees take up water from the soil through their roots and release it into the atmosphere throigh transpiration
- this creates clouds which encourages rainfall in the area
- trees also shade the area decreasing the amount of water lost to evaporation
- removing the trees can therefore affect local climate and cause the area to become much drier
Soil erosion
- removing trees causes rainwater to run off soil more freely
- the trees and cover of vegetation absorb the water releasing it slowly to the soil and streams
When trees are removed, the vegetation in the forest no longer holds back the water - soil particles are washed away by the rain as they are no longer held together by the plant roots
- these soil particles may accumulate in the valleys below where heavy deposits may block rivers causing flooding
- these top layers of the most minerals due to decay + dead leaves - meaning vital nutrients get washed away with the soil in leaching
- this effect is permanent making it difficult for trees to regrow in the area
- any crops grown in future will be low yield
Deforestations effect on methane
Cows
- many cattle farms are on land cleared by deforestation
- methane gas is produced by cows that release large quantities in result of their digestive process
Rice
- land used for growing food for increasing population such as rice
- it grows in paddy fields and releases large amounts of methane as it grows in anaerobic conditions
