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18.2 The Carbon and nitrogen cycle

18.2 The Carbon and nitrogen cycle. Our Biosphere. Learning Targets. Describe the short term cycling of carbon through the processes of photosynthesis and respiration Identify carbon sinks and carbon sources Describe short term and long term storage of carbon

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18.2 The Carbon and nitrogen cycle

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  1. 18.2 The Carbon and nitrogen cycle Our Biosphere

  2. Learning Targets • Describe the short term cycling of carbon through the processes of photosynthesis and respiration • Identify carbon sinks and carbon sources • Describe short term and long term storage of carbon • Describe how human actions interfere with the natural carbon cycle • Describe the nitrogen cycle

  3. Carbon Cycle • All life on earth is built around carbon atoms • Carbon is found in many forms: • Atmosphere (Carbon Dioxide) • Biosphere (Carbohydrates) • Hydrosphere (Calcium carbonate) • Geosphere (Carbon arrangement)

  4. Short term cycle

  5. Long term cycles • Organic materials are buried • AKA – Fossil Fuels • Peat, coal, tar, oil, soil • Carbon stored in the ocean • Many ocean creatures use calcium carbonate (CaCO3) to make their shells or to make the reef material where coral animals live.

  6. Carbon Sinks and Carbon Sources • Carbon sources (add carbon) • Fossil fuel use, deforestation, animals, decaying plant remains • Carbon sinks (store carbon) • Healthy living forests and our oceans act as carbon sinks. • Reservoirs can change from a sink to source and vice-versa

  7. Human Actions Impact Carbon Cycle • Largest source of atmospheric CO2 is burning fossil fuels • When we burn coal, oil, or natural gas, we release the stored carbon in the process of combustion. That means that combustion of fossil fuels is also a carbon source.

  8. Human Actions Impact Carbon Cycle • Second largest source of atmospheric CO2 is deforestation • Carbon sink – Trees absorb CO2 • When trees are cut, lose ability to absorb CO2 • Carbon source- If tree is burned or decomposes

  9. Why Carbon Cycle is Important • Why small amounts of CO2 important? • CO2 absorbs infrared energy from Sun • Greenhouse gases trap heat that should radiate out into space • Greenhouse gas levels increase, global temperatures increase = Global Warming

  10. The Nitrogen Cycle • Most abundant gas in atmosphere • Essential component of organic materials • Amino Acids • Proteins • DNA and RNA • Chlorophyll molecules used for photosynthesis

  11. The Nitrogen Cycle • Must be “fixed” or converted to a usable form • “Fixed” in 3 ways • Lightning • Blue-green algae • Mainly “fixed” by bacteria in soil • Nitrogen fixing bacteria combine nitrogen with oxygen = nitrates or ammonia

  12. Dead Zone

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