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Biogeochemical Cycles. What is a cycle? Some are simple Some are complex.

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Presentation on theme: "Biogeochemical Cycles. What is a cycle? Some are simple Some are complex."— Presentation transcript:

1 Biogeochemical Cycles

2 What is a cycle? Some are simple Some are complex

3 Biogeochemical Cycle The movement of nutrients (atoms) from: –Non-living environment – soil, water, air, rocks, fossil fuels INTO −Living organisms – plants, animals, humans AND BACK AGAIN.

4 The Carbon Cycle


6 Common Molecules With Carbon CO 2 = Carbon Di-Oxide C = Carbon CH 4 = Methane Gas C 6 H 12 O 6 = Sugar

7 Almost all life is based on carbon. The carbon cycle is a closed cycle. The total amount of carbon does not change. Carbon moves between living things, the atmosphere, inside the earth as fossil fuels, the soil and the oceans.


9 Sinks and Sources Sinks store carbon. Examples are the soil, the atmosphere, the ocean, and rocks. Sources release carbon. Examples are burning fossil fuels, animal respiration, methane production

10 Balance? If sinks and sources are in balance, the carbon stays in balance. An overload in the atmosphere (CO 2 ) can cause global warming.

11 Plants & Carbon CO 2 is essential for plants, algae, and some bacteria. O 2 is released into the atmosphere by plants and algae. (Carbon Source)

12 Living plants convert CO 2 to O 2 and carbon through photosynthesis sun and chlorophyll 6CO 2 + 6H 2 O----»C 6 H 12 O 6 + 6O2 Carbon + water sugar+ oxygen When dead plants decompose, carbon returns to the earth; dead plants that do not decompose may be burned, releasing carbon dioxide.

13 What are fossil fuels? The remains of plants that do not decompose. (Carbon Sink) When fossil fuels in the form of coal, oil, or gasoline are burned, carbon returns to the atmosphere as carbon dioxide gas. (Carbon Source)

14 What part do animals play in the oxygen-carbon dioxide cycle? Breathing animals take in oxygen and release carbon dioxide into the air. (Carbon Source) As dead animals decay, carbon returns to the earth. (Carbon Sink)


16 Scan in picture of carbon cycle

17 The Nitrogen Cycle


19 The Nitrogen cycle is a closed cycle. Nitrogen helps to support life by building proteins and other body chemicals.


21 As an organism decays, carbon returns to the earth and soil bacteria produce nitrogen. When coal or gasoline is burned, carbon dioxide and nitric oxides are released into the air.

22 Roots provide a home for nitrogen- fixing bacteria.

23 What is nitrogen fixation? Bacteria that live on the roots of plants remove pure nitrogen from the air and release it into the soil.

24 . Nitrogen in the air can not be used directly by most organisms. To be useful, nitrogen is removed from the air and combined with other elements to form nitrogen compounds. This process is called nitrogen fixation.


26 Decomposers break down animal waste and release nitrogen into the soil.



29 What two ways form pure nitrogen gas? 1. By bacteria during nitrogen fixation 2. By denitrifying bacteria


31 BrainPop

32 Add pic of nitrogen cycle

33 Biogeochemical Cycles

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