Organisms are really important for recycling carbon and nitrogen. This recycling helps our ecosystems and the air we breathe.

How Organisms Help with the Carbon Cycle

1. Photosynthesis:

   • Plants take in about 120 billion metric tons of carbon dioxide (CO2) each year.
   • They turn CO2 into food and other materials that support different life forms.

2. Respiration:

   • Animals breathe out about 100 billion metric tons of CO2 as they use energy.
   • Tiny organisms called decomposers also release carbon back into the air when they break down dead things.

3. Decomposition:

   • Bacteria and fungi help break down dead plants and animals.
   • This process returns carbon to the soil and the atmosphere.

How Organisms Help with the Nitrogen Cycle

1. Nitrogen Fixation:

   • Some bacteria can change nitrogen from the air into ammonia.
   • This makes nitrogen available for plants to use.
   • This process adds about 140 million metric tons of nitrogen every year.

2. Nitrification:

   • Bacteria can turn ammonia into nitrates, which plants can use to grow.

3. Denitrification:

   • Other bacteria turn nitrates back into nitrogen gas, which goes back into the air.
   • This happens with about 100 million metric tons of nitrogen each year.

By doing these things, organisms help keep the amount of carbon and nitrogen balanced in our ecosystems.