Decay

    Cards (10)

    • Decomposition - the breakdown of dead materials into simple organic matter
    • What is decomposition done by?
      Decomposers (fungi and bacteria) and detritivores (worms etc).
    • Detritivores are animals which feed on dead organic matter.
    • Factors which affect the rate of decomposition;
      • Oxygen
      • Moisture
      • Temperature
    • How oxygen affects rate of decomposition;
      More oxygen = more aerobic respiration = more energy released = faster rate of decomposition
    • How temperature affects the rate of decomposition;
      Higher temperature = particles have more kinetic energy and enzymes are closer to optimum temperature = higher rate of reactions = more decomposition
      However, if temperatures rise too high, it will cause the enzymes to denature = decreasing rate of reaction = decreasing rate of reaction.
    • How water/moisture affects rate of decomposition;
      • As decomposers need water to survive, the rate of decomposition will increase in moist conditions.
      • However, if the soil becomes waterlogged then the oxygen levels will fall, which will decrease the rate of decomposition.
    • Compost - mixture of decaying organic material that is used as fertiliser.
    • Biogas;
      • Microorganisms can decompose things without oxygen - called anaerobic decay.
      • This produces methane.
      • When methane is combusted it releases lots of energy.
    • Biogas generators;
      • Are large containers where plant and animal waste is left to decay anaerobically.
      • Once the biogas is extracted there is a sludgy materials left over, which has a high density of use minerals. So it can be used as fertiliser.