1. The Carbon Cycle

2. Why is Carbon Important?
All organisms are based on the atom carbon

3. So?
Carbon molecules can be solid, liquid or gas under normal conditions. So carbon can form hard rock, watery organisms, it can be dissolved in water or carried throughout the Earth at carbon dioxide gas

4. The Carbon Cycle
Like water in the water cycle, carbon atoms continually cycle through living organisms, the oceans, the atmosphere and the land (lithosphere).
That movement of carbon is called the carbon cycle

6. Movement of Carbon
Carbon (in the form of carbon dioxide) moves from the atmosphere to plants through the process of photosynthesis

7. Movement of Carbon
Carbon moves from plants to animals through the FOOD CHAIN.

8. Movement of Carbon
When those plants or animals die the carbon moves into the ground.
Some becomes buried for millions of years and turns into fossil fuel.

9. Movement of Carbon
Carbon can also move from living things to the atmosphere.
How????

10. Movement of Carbon
Respiration or breathing

11. Movement of Carbon
Carbon moves from fossil fuels back to the atmosphere when fossil fuels are burned. The burning of fossil fuels produces carbon dioxide.

12. Movement of Carbon
Carbon may also move from the atmosphere to the oceans

13. Photosynthesis and Respiration are key process in the Carbon Cycle

14. Carbon and Climate Change
The climate has always changed, it is the accelerated rate of change that concerns scientists

15. Fossil Fuels
Humans discovered that the burning of fossil fuels releases energy that can be used for
Heat
Transportation
Manufacturing/construction

16. Since the industrial revolution humans have burned large amounts of fossil fuels such as coal, oil and natural gas.

17. Carbon dioxide is a greenhouse gas. It traps heat in the atmosphere

18. Scientists estimate that there is 30% more carbon dioxide in the atmosphere than there was 150 years ago
It is believed that the increase in carbon dioxide in the atmosphere is causing a warming of the Earth.

19. The Nitrogen Cycle

20. Like carbon, nitrogen in an element

21. Biotic
It is found in both plants and animals
Where?

22. DNA, RNA and proteins

23. Abiotic
Nitrogen is also an important part of the atmosphere and the soil.

24. The Nitrogen Cycle
The movement of nitrogen atoms between living things, dead things, the air, soil and water is called the Nitrogen Cycle.

25. The Atmosphere
Most of the nitrogen on the Earth is present in the atmosphere as nitrogen gas.
Nitrogen gas is the main component in the Earth’s atmosphere

26. The Problem
Animals and plants can’t use nitrogen in the form of nitrogen gas.

27. The Solution Nitrogen fixing bacteria
Through the process of nitrogen fixation the bacteria convert nitrogen gas to ammonia

28. The Next Step
Next, other bacteria in the soil change the ammonia to nitrates and nitrites.

29. Now plants can use the nitrogen from the soil or water in which they live.

30. Animals get the nitrogen then need by eating plants or by eating other animals.

31. When the organism dies the decomposers return nitrogen to the soil in the form of ammonia

32. The nitrogen may be converted back to nitrogen gas by bacteria in a process called denitrification.
Denitrification releases nitrogen gas back into the atmosphere.

33. Nitrogen and Pollution
The burning of fossil fuels also releases nitrogen into the atmosphere When that nitrogen combines with water vapor it forms nitric acid

34. Acid Rain
That nitric acid may travel great distances before it falls back to the Earth as Acid Rain.

35. Acid Rain
Major pollution problem

37. Acid rain describes any form of precipitation (rain, snow, fog) and dry matter that settle back on Earth

38. Effect on Plants
Acid rain can kill plants by damaging their leaves and changing the soil conditions.
Acid rain also may dissolve and release toxic elements such as mercury from the soil

40. The Effects of Acid Rain
Contamination of water supplies - harmful to human health
Cause chemical weathering of buildings e.g. Westminster Abbey
Crop yields reduced by increasing soil acidity
Increased acidity of freshwater lakes killing both fish and plant life - e.g. 18,000 lakes in Sweden badly poisoned - over 4000 have no fish left.
Annual cost of damage from acid rain in Europe is estimated to be between $0.5 and $3.5 billion.

41. International Problem
The nitrogen can travel great distances before it falls back to Earth as acid rain
The countries the suffer the effects of acid rain are not necessarily those that created the pollution that caused the acid rain