Carbon Sinks

• Carbon cycle


  • Various processes by which carbon, in the form of carbon dioxide, is constantly being removed from and released into the atmosphere.
• Removal of carbon dioxide from the atmosphere

  • Producers absorb carbon dioxide from the atmosphere and convert it to glucose during photosynthesis.
• Transferring carbon-containing compounds along food chain.

  • Glucose in producers can be used to make other carbohydrates, proteins, and fats.
  • Carbohydrates, proteins, and fats are transferred along the food chain by feeding.
• Release of carbon dioxide into the atmosphere

  • Both producers and consumers carry out aerobic respiration. Glucose is broken down to produce carbon dioxide which is released into the atmosphere.
  • Decomposers break down carbohydrate, proteins and fats in the organic matter (e.g. faeces, urine, dead organism, and uneaten body parts) and release carbon dioxide into the atmosphere.
  • Combustion of carbon-containing compound in fossil fuels releases carbon dioxide into the atmosphere.
• Importance of carbon cycle

  • Ensures a continual supply of carbon dioxide for plants to carry out photosynthesis
  • Allows energy flow in the ecosystem through the carbon-containing compounds, via food chains
  • Ensures carbon dioxide concentration in the atmosphere is relatively constant.
• Carbon sinks


  • An area that stores carbon, in the form of carbon-containing compounds, from the atmosphere for a long period of time, storing more carbon than it releases.
• Carbon Sinks : Oceans

  • Largest carbon store on Earth
  • Carbon dioxide can dissolve in water.
  • Dissolved carbon dioxide is used by algae/phytoplankton for photosynthesis.
  • Carbon compounds in dead organisms are buried in seabed as fossil fuels
• Carbon Sinks : Forests


  • Producers absorb carbon dioxide from the atmosphere and convert it to glucose during photosynthesis.
  • Glucose is converted to other carbon compounds used in the growth of plant parts (e.g tree trunks, branches, etc.).
  • Buried carbon compounds from dead trees can be stored as fossil fuels