ELSS L6 - Carbon exchange

  • Created by: Hadley023
  • Created on: 07-11-18 12:38
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  • Carbon exchange
    • Precipitation
      • Atmospheric CO2 dissolves in rainwater to form carbonic acid.
      • Human activities are increasing the acidity of rainfall (increase CO2 in the atmosphere) = ocean surface waters are becoming more acidic.
      • Marine and ocean reservoirs. Rate at which CO2 dissolves into the ocean is dependent on the temperature.
      • Temperature rise by the end of the century.
    • P'synth
      • Using the Sun's energy, CO2 from the atmosphere and water, green plants and marine phytoplankton convert light energy to chemical energy.
      • Flux of carbon from the atmosphere to land plants and phytoplankton via p'synth average around 120 gigatonnes.
    • Chemical weathering
      • Most weathering involves rainwater which contains dissolved CO2.
      • Dissolves limestone and chalk - carbonation.
      • Transfers carbon to the atmosphere, streams, rivers and the ocean.
      • Rate of process is influenced by geology.
    • Biological weathering
      • Rainwater mixed with dead and decaying organic material in the soil forms humid acids (important to tropical environments)
    • Physical weathering
      • Freeze thaw breaks rocks down into smaller particles but involves no chemical weathering.
      • Dissolves into smaller pieces, increases surface area, increases chemical weathering.
    • Respiration
      • Process in which carbohydrates fixed in p'synth are converted to CO2 and water.
      • Plants and animals use these carbohydrates to provide energy needed for metabolism and growth.
    • Decomp.
      • Decomposer organisms breakdown DOM, extracting energy and releasing CO2 into the atmosphere and mineral nutrients to the soil.
      • Anaerobic decomposition in waterlogged soils releases methane. Contributes to GGC as methane is extremely potent.
      • Rates of decomp depend on climatic conditions. Increase GGC due to increase temp = increase decomp.
    • Combustion - natural
      • Organic material reacts in the presence of oxygen. Combustion releases CO2 (natural combustion e.g. wildfires.
    • Combustion - humans
      • Human activities e.g. cleaeing of forests (slash and burn) and combustion of fossil fuels (due to increased affluence).


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