The major reservoir of carbon on Earth is the ocean. It holds the largest amount of carbon compared to other reservoirs, storing about 37,000 billion tons of carbon mainly in the form of dissolved carbon dioxide, bicarbonate, and carbonate ions as well as marine life. The ocean is often called the largest active carbon reservoir because it plays a crucial role in regulating atmospheric carbon levels. Other significant carbon reservoirs include:
- The terrestrial biosphere, which encompasses living organisms on land (plants, animals, microorganisms) and soil organic matter.
- Sediments and fossil fuels (coal, oil, natural gas) formed from ancient organic matter.
- The atmosphere, which contains carbon mainly as carbon dioxide but in much smaller quantities than the oceans.
- The Earth's interior (mantle and crust), where carbon is stored mainly in minerals like limestone.
Among these, the ocean is the biggest reservoir of carbon, storing substantially more carbon than the atmosphere, terrestrial biosphere, or fossil fuels combined. This makes the ocean the primary carbon sink on our planet.
