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Gaia Theory

Gaia Theory. The theory that earth and everything on it constitutes a self regulating living entity Positive feed back loops – “spiral out of control” Negative feedback loops – “keep balance”. Spreading center. Ocean trench. Oceanic tectonic plate. Oceanic tectonic plate. Plate movement.

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Gaia Theory

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  1. Gaia Theory • The theory that earth and everything on it constitutes a self regulating living entity • Positive feed back loops – “spiral out of control” • Negative feedback loops – “keep balance”

  2. Spreading center Ocean trench Oceanic tectonic plate Oceanic tectonic plate Plate movement Plate movement Collision between two continents Tectonic plate Subduction zone Oceanic crust Oceanic crust Continental crust Continental crust Cold dense material falls back through mantle Material cools as it reaches the outer mantle Mantle convection cell Hot material rising through the mantle Two plates move towards each other. One is subducted back into the mantle on a falling convection current. Mantle Hot outer core Inner core Fig. 14-3, p. 346

  3. Soil Profile A column of soil contains layers or horizons. Erosion Salinization

  4. Freshwater Resources • Our freshwater comes from rivers, lakes and groundwater (aquifers). • 70% of the worlds freshwater is used to irrigate crops. • 20% is used in industry (it takes 25 full bathtubs of water to make a t-shirt). • 10% is used by cities and residences.

  5. http://planetgreen.discovery.com/videos/focus-earth-2-pacific-plastic-the-garbage-patch.htmlhttp://planetgreen.discovery.com/videos/focus-earth-2-pacific-plastic-the-garbage-patch.html Surface Currents

  6. ENSO • El Nino - Southern Oscillation - Every few years warm water builds up from Australia to South America changing upwelling areas as well as global weather patterns.

  7. Normal Conditions

  8. ENSO Conditions

  9. Demographic Transition

  10. Doubling Time • Rate of growth (%) = 70/DT • If a population doubles every 35 years, what is the rate of growth for this population?

  11. Calculations • If you drive a car with average gas mileage (25 MPG) for 8000 miles each year how many pounds of CO2 will your average car produce? (One gallon of gas produces 9 lbs of CO2.)

  12. Water Cycle

  13. Carbon Cycle

  14. Nitrogen Cycle

  15. Phosphorus Cycle

  16. Sulfur Cycle

  17. Coal-burning power plants • Inefficient and complicated

  18. Where does our energy come from?

  19. Green Revolution • Increasing crop yields by using fertilizers, pesticides, irrigation and hybrid or GM plants.

  20. Forest Ecosystems • Old growth vs second growth • Methods of harvesting trees: • Selective cutting • Clear Cutting • Strip Cutting

  21. Ozone Depletion • Seasonal thinning of the ozone layer caused by: • Chlorofluorocarbons - air conditioners, fridges, aerosol cans, cleaners, fumigants • Hydrobromoflurocarbons - fire extinguishers • Methyl bromide - fumigant • Hydrogen chloride - space shuttles • Various chemicals from cleaning solvents

  22. Ozone Depletion is Bad • More UV-A and UV-B radiation will reach the earth’s surface resulting in more cataracts, sunburns and skin cancer. • Increased radiation could impair or destroy phytoplankton.

  23. Reversing Ozone Depletion • Stop producing all ozone-depleting chemicals. (60 years to recover) • Warming the troposphere makes the stratosphere cooler which slows down ozone repair. • Copenhagen Protocol (1992) - 191 countries agreed to phase-out key ozone-depleting chemicals.

  24. Species What? • Keystone species • Indicator Species • Foundation Species • Invasive Species • Endangered species

  25. Industrial vs. Photochemical

  26. Types of Pollutants • Primary pollutants – harmful chemicals emitted directly into the air from natural processes and human activities. • Secondary pollutants – new chemicals formed by the reactions of primary pollutants.

  27. Types of Pollutants • Carbon oxides – (CO and CO2) burning fossil fuels and plants. • Nitrogen oxides and nitric acid – cars and coal burning power plants, fertilizers and animal wastes. • Sulfur dioxides and sulfuric acid – burning sulfur containing coal, oil refining and smelting of sulfide ores.

  28. Types of Pollutants • Particulates – suspended particulate matter (SPM) – dust, wildfires, sea salt, coal burning, cars, plowed fields, road construction, unpaved roads, smoke. • Ozone – O3 in photochemical smog, causes breathing problems, aggravates lung and heart disease, reduces resistance to colds and pneumonia, irritates eyes, nose and throat, damages plants, tires, fabrics and paints. • Volatile organic compounds (VOC’s) – organic cpds that exist as gasses in the atm, mostly hydrocarbons. Sources are plants, wetlands, cows, rice paddies, industrial solvents, dry-cleaning fluids, plastics, gasoline, drugs and synthetic rubber.

  29. Evaluating Chemical Hazards • Toxicology - study of harmful effects of chemicals on humans and other organisms. • Toxicity - measure of how harmful a substance is. (LD50)

  30. Dams – fish migration, power, water source, upstream flooding, nutrient deposition Waste Management – landfills, recycling Environmental Disasters • Bhopal, India • Aral Sea • Love Canal

  31. Laws • Clean Water Act • Clean Air Act • Safe Drinking Water Act • Endangered Species Act • National Environmental Policy Act

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