Nitrogen cycle

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Nitrogen cycle

  1. 1. TheNitrogenCycle<br />IB Biology<br />
  2. 2. What is nitrogen?<br />
  3. 3. Periodic Table<br />Nitrogen is in the Nonmetals/BCNO Group<br />
  4. 4. Where is nitrogen found in the environment?<br />
  5. 5. The largest single source of nitrogen is in the atmosphere.<br />Nitrogen makes up 78% of our air!<br />
  6. 6. It is one of nature’s great ironies…<br />Nitrogen is an essential component of DNA, RNA, and proteins—the building blocks of life. <br />Although the majority of the air we breathe is nitrogen, most living organisms are unable to usenitrogen as it exists in the atmosphere!<br />
  7. 7. How does atmosphericnitrogen get changed into a form that can be used by most living organisms?<br />N<br />N<br />
  8. 8. By traveling through one of the four processes in the Nitrogen Cycle!<br />(1) Nitrogen Fixation<br />(4) Denitrification<br />Nitrogen Cycle<br />(3) Nitrification<br />(2) Ammonification<br />
  9. 9. Nitrogen in<br />the air<br />animal protein<br />nitrogen fixing plant<br />eg pea, clover<br />plant made<br />protein<br />dead plants & animals<br />urine & faeces<br />denitrifying<br />Pseudomonas <br />denitrificans<br />root nodules<br />(containing Rhizobium)<br />decomposition by bacteria & fungi<br />nitrates absorbed<br />ammonia<br />nitrates<br />nitrites<br />Azobacter<br />Nitrobacter<br />(nitrifying bacteria)<br />
  10. 10. Yourtask!<br />Imagine you are a nitrogenatom!<br />Sendpostcardtoyournitrogenfriendsexplainigthefollowing:<br />-Whereyouwere… <br />-Whereyou are now….<br />-Whereyou are goingnext….<br />Don´tforgettoexplainanymeetingswith bacteria orhowyouhavechanged as a molecule!<br />
  11. 11. Sewage<br />IB Biology<br />
  12. 12. Flushed with success?<br />To draw attention to the<br />people who do not have toilets or proper sanitation<br />Built by Sim Jae-Duck, involved with World Toilet Association<br />Seoul, South Korea<br />Why?<br />2 billion<br />
  13. 13. Sewage<br />What is it?<br />Untreated raw sewage is waste which has come from our toilets, sinks, baths etc. <br />What does it contain? examples<br /><ul><li> organic material
  14. 14. mineral salts
  15. 15. bacteria</li></ul>Faeces, food fragments, enzymes, soap, gel, hair<br />Phosphates, nitrates<br />Some from detergents & washing powders<br />Food poisoning, disease-causing<br />
  16. 16. Environmental damage<br />14 July 07<br />14 Sept 07<br /><ul><li> In rivers can cause algal blooms (as sewage is a good food source for them), killing animals and plants living in water.
  17. 17. May release methane and ammonia gases (foul smelling).</li></ul>Eutrophication<br />Sussex River Ouse<br />Sea trout nursery<br />
  18. 18. Eutrophication<br />High concentrations of inorganic substances can cause algal blooms<br />Substances encourage rapid growth of algae and blue-green bacteria<br />
  19. 19. Biological Oxygen Demand<br />Sample of water measured at 20˚C over 5 days <br />2. Increase in organic pollutants increases number of bacteria<br />BOD will increase<br />Copy the steps above and give a reason as to why each step is occurring<br />-use your handout to help!<br />
  20. 20. Sewage treatment works<br />
  21. 21. Why treat it?<br /><ul><li> May cause disease if it contaminates drinking water, due to harmful bacteria present.</li></ul>Examples of diseases which may be spread by untreated sewage.<br />dysentery, typhoid, cholera<br />
  22. 22. Sewage treatment process<br />0<br />Untreated raw sewage enters the sewage works<br />1a<br />1b<br />Aerobic conditions<br />Sedimentation tank<br />2<br />3<br />Anaerobic conditions<br />4<br />5<br />Sewage water to: <br />Screening (coarse filter)<br />Metal grids strain out large objects<br />Grit tank<br />Stones and heavy solids sink to the bottom<br />Lighter solids such as faeces sink to the bottom and form a sludge<br />
  23. 23. Anaerobic conditions<br />Aerobic conditions<br />3<br />4<br />5<br />6<br />*or biobeads<br />Sludge digestion tank<br />Bacteria feed on sludge, producing methane. Can be used as a fuel.<br />Activated sludge tank<br />Sludge mixed with<br />extra air (oxygen), stirred, bacteria produce harmless liquids.<br />Biological filter tank<br />Fluid from tank sprinkled over stones* coated with microbes. Bacteria produce harmless liquids<br />Treated waste emptied into rivers<br />
  24. 24. Now complete yourSewageTreatmentcut and paste sheet!<br />
  25. 25. Increasing energy levels<br />Biofuels<br />The main fuels which can be obtained from biomass: <br /><ul><li> Methane
  26. 26. Alcohol</li></ul>Methane (biogas) production occurs naturally by fermentation (anaerobic respiration) when animal or plant material decays.<br />Both are products of fermentation<br />
  27. 27. Generation of methane from biomass<br />Fermentation of faeces<br />-aerobic bacteria hydrolysecarbs, proteins, fats<br />Oxygenused up <br />-acetogenic bacteriaconvertsugarsto short chainfattyacids (e.g.acetate), CO2 and H2<br />-acetogenesisstage<br />Methanogenesis<br />-final stageisanaerobicand involvesmethanogenic bacteria<br />-conversion of actetatetomethane<br />Temp: 30-40˚C<br />

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