Trace the cyclical movement of carbon in the three realms of the earth.

Cyclical Movement of Carbon in the three realms of the Earth

1. Carbon is present in the atmosphere as carbon dioxide (CO₂).

2. Plants absorb CO₂ from the atmosphere during photosynthesis, and convert it into organic matter.

3. When animals eat plants, carbon enters their bodies.

4. Both plants and animals release CO₂ back into the atmosphere during respiration.

5. When plants and animals die and decay, some of the carbon gets stored in the lithosphere as fossil fuels (like coal and petroleum).

6. When these fossil fuels are burnt, CO₂ is released back into the atmosphere.

7. Oceans in the hydrosphere absorb CO₂ from the air. Some marine organisms also use it to form shells.

8. When these organisms die, carbon settles to the ocean floor and becomes part of the marine sediments (lithosphere).