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Ecosystems and the Physical Environment Chapter 5
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The Gaia Theory Dynamic Equilibrium Negative Feedback Positive Feedback
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How Chemicals Cycle Biogeochemical Cycle The complete path a chemical takes through the three major components – or reservoirs – of Earth’s systems 1.Atmosphere 2.Hydrosphere 3.Lithosphere
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Cycles Carbon 1.Lipids 2.Nucleic Acids 3.Carbohydrates 4.Amino Acids Nitrogen 1.Amino Acids Phosphorus 1.ATP 2.DNA 3. Cell Membranes Sulfur 1.Amino Acids 2.Keratin Fixed amounts of all elements on earth * Oxidation describes the loss of electrons by a molecule, atom or ion * Reduction describes the gain of electrons by a molecule, atom or ion
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Carbon Cycle Billions of Tons http://www.youtube.com/watch?v= 0Vwa6qtEih8&feature=related
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Carbon Silicate A weathering Cycle: 1.Atmospheric CO 2 forms H 2 CO 3 (Carbonic Acid) precipitation which moves through soil 2.H 2 CO 3 dissociates & forms H + & HCO - 3 (bicarbonate) 3.Silicate rich minerals interact with the free H + to release Ca 2+ 4.Shellfish 5.Subduction – silicate formation at temperatures above 300 °C
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Carbon Silicate Believed to provide important negative feedback mechanisms that control the temperature of the atmosphere.
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Nitrogen cycle Nitrogen cycle: Atmospheric nitrogen (N 2 ) Nitrogen fixation by humans Biological nitrogen 1. fixation 2. Nitrification NH 3 & NH 4 - NO 3 - 3. Assimilation 5.Denitrification Plant & animal proteins Decomposition - urea 4. Ammonification Internal cycling (Ammonia) Lightning Volcanoes Bacteria (Nitrates & Nitrites) (Oxidation) NO 3 - → NO 2 - → NO → N 2 O → N 2 gas
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Nitrogen Cycle & Steps 1.Nitrogen Fixation is the conversion of elemental nitrogen(N 2 ) to organic ammonia(NH 3 ) by bacteria, lightning, industry, volcanoes. 2.Nitrification - conversion of ammonia or ammonium (NH 4 ) into nitrites(NO - 2 ) and then into nitrates (NO - 3 ) by bacteria 3.Assimilation- plants absorb nitrates or ammonia 4.Ammonification - nitrogen is converted into ammonia from animal waste or dead organisms by aerobic bacteria 5.Denitrification - anaerobic bacteria convert nitrates & nitrites to nitrogen gasses off to atmosphere 1.Nitrogen is not a reactive molecule 2.78% atmosphere N 2 & 21% oxygen &.038% CO 2 YouTube: http://www.youtube.com/watch?v=m4YToXw724w&feature=relatedhttp://www.youtube.com/watch?v=m4YToXw724w&feature=related
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Phosphorus Cycle Does not include the atmosphere YouTube: http://www.youtube.com/watch?v=RKkC2JpjaGc&feature=related http://www.youtube.com/watch?v=RKkC2JpjaGc&feature=related
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Phosphorus Cycle
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Phosphorus Brazil
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Guano
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Accelerated Eutrophication
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Cycling of Materials within Ecosystems Sulfur cycle: YouTube: http://www.youtube.co m/watch?v=BzPeA9oQ Nl8 http://www.youtube.co m/watch?v=BzPeA9oQ Nl8
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Cycling of Materials within Ecosystems Hydrologic cycle:
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Tectonic Cycle Tectonic cycle: Involves creation and destruction of the solid outer layer of Earth, the lithosphere Plate tectonics: The slow movement of these large segments of Earth’s outermost rock shell (7 plates) Boundaries between plates are geologically active areas
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Internal Planetary Processes
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Volcanic Activity 2011
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Internal Planetary Processes Plate boundaries
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Internal Planetary Processes Plate boundaries
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Tectonic Cycle: Plate Boundaries Divergent plate boundary: New lithosphere is produced (seafloor spreading) Convergent plate boundary: Produces linear coastal mountain ranges or continental mountain ranges Transform fault boundary: San Andreas Fault in California
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Internal Planetary Processes Volcanoes Most volcanoes occur along subduction zones
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Internal Planetary Processes Volcanoes Some occur along spreading zones Few, such as Hawaiian Islands, not associated with plates.
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Internal Planetary Processes Earthquakes caused by release of built up stress, typically along faults movement releases seismic waves Typical side effects include: 1) Landslides 2) Tsunamis
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