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CARBON CYCLE (Carbon (Global Distribution (CO2 is decreased in summer -…

- - - - These concs. dropped dramatically
    - - These concs. are increased each year
- - - - Atmosphere
      - Oceans
      - Biosphere - living orgs. in the soil
    - - Rocks
      - Sea floor seds.
      - Fossil fuels
    - - Photosyn. - absorbs CO2
      - Resp. - release CO2
      - Decomposition - releases CO2
  - - - When C joins with another atom, it forms part of another store
    - - Some C-rich sedimentary rocks undergo subduction and are vented into atmosphere
      - Carboantion - chemical weathering breaks down compounds, releasing CO2
      - Fuel combustion/wildfires
    - - When C atoms are stored in oceans for 350 years
      - Due to C exchange between ocean + atmosphere
  - - - C is dissolved into oceans but released via diff. methods
- - - - Soil stores C in 2 forms
        
        Inorganic C - form weathering of carboantes
        
        Organic carbon
        
        From humus (plant remains)
    - - Carboante rocks + deep sea carbonates
    - - Planktonic orgs. die + their skeletonc accumulate on ocean bed
    - - CO2 is important trace gas
      - Makes up 0.04% of atmopshere
    - - Largest living space on E
      - Mostly microscopic orgs.
    - - Below the depths that light can penetrate to
      - Respiration via marine orgs, inc. bac.
    - - 86% of terrestrial C is held in forests
      - So forests are sig, for C sequestering
    - - Non-renewable sources of primary energy
      - Some countries have based their entire economy on their export e.g. Suadi Arabia
  - - - Glucose + O2 react in cells = CO2 + H2O + energy
      - Occurs in all living cells
      - Releases C in atmosphere
      - Occurs in all biomes e.g. phytoplankton blooms in surface ocean
    - - Dead organic matter breaks down into organic carbon
      - This is carried out by decomposers + detritivores
      - Recycles C from living matter back into atmosphere
      - Occurs rapidly in tropical forest ecosystems; is slower in arctic ones
    - - CO2 + H2O = carbohydrates
      - Moves C from atmosphere to biomass store
      - Occurs in all biomes
      - Rate is dependent on light, temp. + availability of nutrients
    - - Breakdown of carbonate rocks often by carbonation - releases C into streams + rivers as bicarboante ions
      - Occurs fast in tropical climate where there is limestone
    - - C-rich sedimentary rocks are subducted into upper mantle - means that CO2 is outgassed at SDZ
      - Heat + pressure of SDZ metamorphoses carboante rocks in silicates, releasing CO2
      - Occurs at active island arcs where marine seds. are being subducted
    - - Some C is oxidised to CO2
      - Occurs when fields are ploughed and soil overturned = CO2 in contact with atmosphere
    - - Wildfires, fossil fuels
      - 2013 - 85% of UK's electricity was generated via fossil fuels
- - - - Suitable climate (sun, heat, water) = evergreens - can photosyn. + resp.
      - Higher veg. density
      - Sun v. high in sky = increased intensity