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Cycles 2
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Cycles 2

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  1. Cycles 2

  2. Nitrogen Cycle • Crucial to proteins, enzymes, chlorophyll, DNA - essential to life. • Nitrogen gas most common gas in atmosphere (78%) • Organisms can’t use it directly!!! • Plants can only use NHx (ammonium compounds) • Animals obtain it by eating plant tissues

  3. 3 ways to obtain organic nitrogen: • Need nitrogen fixing bacteria • In roots of legumes • Legumes are a major crop • Loss of soil and arable farmland??? • Decomposition • Loss of biodiversity of fungus • Lightening • Enter soil with rain

  4. Other Inputs of Nitrogen • Volcanoes • Industrial activities • Emissions • combustion • Agriculture • Pesticides • Fertilizers • Eutrification

  5. Phosphorus Cycle • Found in DNA, ATP, cellular membranes • Major structural component of skin, bones, teeth • Not found in gaseous state • Goes from land-sediments-oceans-back to land • Enters by decomposition • Wind and water erode rocks • Particularly important as P is a limiting factor for aquatic habitats

  6. Essentially lost here

  7. Hydrologic Cycle • Water moves from hydrosphere to atmosphere and lithosphere • Then back to hydrosphere • Removals from hydrosphere: • Transpiration by plants • Deforestation? Loss of diversity?? • Solar driven evaporation • Increased due to global warming???

  8. Returns to earth: • Precipitation • Global warming and climate changes??? • Stored in: • Lakes • rivers • Ponds • Streams • Aquifers • Wetlands • etc.

  9. Quality and availability of water at any one time or place is dependant on humans!: • Usage • Condition of earth’s surface where it falls • Continued ability of soil, forests, wetlands, etc.to absorb, clean and store it • Soil erosion • Deforestation • Pollution • Habitat loss