Across
- 3. This chemical reaction consumes atmospheric $CO_2$ and sends it into rivers.The tectonic process that returns carbon from the seafloor to the mantle.
- 4. This is the primary natural "outgassing" method for the long-term cycle.Marine organisms use calcium and bicarbonate to build these structures.
- 5. Most of the planet's carbon is locked in rock layers rather than the air.Geological "vents" that release $CO_2$ back into the atmosphere.
Down
- 1. Carbonate sediments on the ocean floor are pushed deep into the Earth's interior.This type of rock, like limestone, stores the majority of Earth's carbon.
- 2. When these organisms die, they sink and eventually form carbonate rock.