A2 1 Human Impact

Question 1

Explain global warming

Answer 1

Short wave radiation passes through atmosphere

Earths surface warms and radiations back long wave radiation (heat)

Some reaches space but some long wave radiation is re-radiated back causing earth to warm

Greenhouse gases absorb some of the long wave radiation from the earth

Question 2

Co2 sources and how to reduce it

Answer 2

Respiration of organisms

Combustion fossil fuels

Question 3

Methane ch4 sources and remedies

Answer 3

Bacteria living in marshes and rice paddy fields

Bacteria in gut of cows and other ruminant animals

Use digesters to decompose organic waste and burn methane produced

Question 4

Nitrous oxide (n2O) source and remedies

Answer 4

Denitrifying bacteria acting on nitrates
Combustion of fossil fuels

Reduce the use of artificial ferrilizers especially on souls liable to water logging

Reduce use of fossil fuels

Question 5

Chlorofluorocarbons CFC’s source and remedies

Answer 5

Coolant in fridgerators
Propellants in aerosol sprays

Use alternatives

Question 6

Ozone (O3) source and remedies

Answer 6

Produced by the action of sunlight on gases from vechicle exhausts

Reduce vechicle exhaust emissions

Question 7

Effects of global warming

Answer 7

Rise in sea levels - melting polar caps and glaciers and expansion of water. Causes flooding in low lying areas

Distribution of climate and weather patterns - change in wind patterns and leading to changes in distribution of rainfall and extremes wearther

Changes in crop production - from gradual increase in temperature at earths surface

Altered distribution of willd animals and plants - resulting from temperature changes. The purple sun star (Solaster endeca) is a distinctive star fish found in off shore NI. It is cold water species and appears to be declining in shallower waters retreating to cooler deeper waters

Question 8

Effects of acid rain

Answer 8

Acid rain directly toxic to leaves and pine needles in forest ecosystems

Inhibits action of decomposers in soil and districts cycling of nutrients

In aquatic systems aluminium leaches into water ways and causes gills to become covered in thick mucus which prevents oxygen uptake and kills invertebrates and fish

Fish eggs fail to hatch if exposed to pH lower than 5.5

Question 9

How to control acid rain

Answer 9

Using low sulfur fuels
Increase use of natural gas in place of coal which has high sulfur content
Use catalytic converters in engines and oil burners to remove nitrogen dioxide

Question 10

Eutrophication

Answer 10

Naturally occurring process of nutrient enrichment of water bodies as a result of rock erosion and run off from surrounding catchment

Increase in artificial enrichment from human activity

How:
Increased leaching and run off from artificial fertilisers which are rich in nitrate and phosphate
Release of phosphate containing detergents from house hold
Produced of decomposition of organic matter discharged into water

Problems:
Increased nitrate and phosphate in water causes massive algal blooms
Dense algae reduces the amount of sun light available to penetrate the organisms below it
Algae use up available ions and eventually die as they do not receice sufficient light or nutrients
Dead algae are composed by bacteria which use up oxygen as they respire
Oxygen depletion due to this causes many species of invertebrates and fish to die
Water extracted for drinking may taste sour and unacceptable taste
Can be harmful to health due to high nitrate level
Food chain collapsed
Fisheries being lost

Remedies:
Reduce risk of fertiliser run-off into water - not using fertiliser when heavy rain forecasted, not applying fertiliser adjacent to water bodies, test souls for current ion content for fertilisers can be adjusted so that supply does not exceed demand