The Carbon Cycle

• Carbon Cycle


  Recycling of nutrients in the environment, with a balance between what goes in and what goes out
• Elements are Cycled Back to the Start of the Food Chain by Decay


  1. Living things take materials from the world around them

  2. Materials are returned to the environment in waste products or when organisms die and decay

  3. Materials decay as they are broken down by microorganisms

  4. Decay puts the stuff that plants need to grow back into the soil

  5. In a stable community, the materials taken out of the soil and used by plants etc. are balanced by those put back in
• The Constant Cycling of Carbon is called the Carbon Cycle
• The Carbon Cycle


  1. CO2 in the air

  2. Photosynthesis by plants

  3. Plant respiration

  4. Animal respiration

  5. Decay of carbon compounds in plants and animals

  6. Burning of fossil fuels
• CO2 is removed from the atmosphere by green plants and algae during photosynthesis
• The carbon is used to make glucose, which can be turned into carbohydrates, fats and proteins that make up the bodies of the plants and algae
• When the plants and algae respire


  Some carbon is returned to the atmosphere as CO2
• When the plants and algae are eaten by animals


  Some carbon becomes part of the fats and proteins in their bodies
• When the animals respire


  Some carbon is returned to the atmosphere as CO2
• When plants, algae and animals die

  Detritus feeders and microorganisms feed on their remains
• When detritus feeders and microorganisms respire

  CO2 is returned to the atmosphere
• The combustion (burning) of wood and fossil fuels


  Releases CO2 back into the air
• The carbon (and energy) is constantly being cycled from the air, through food chains (via plants, algae and animals, and detritus feeders and microorganisms) and eventually back out into the air again