The Ocean Carbon Cycle
The ocean is often called a carbon sink because it can store up to 50 times more CO2 than the atmosphere. It absorbs carbon from the air and releases it back into the atmosphere, playing a crucial role in regulating global climate.
How Does It Work?
Carbon dioxide molecules dissolve into surface waters. Some CO2 remains as a gas, while others react with water to form carbonic acid. Small marine plants, known as phytoplankton, transform CO2 into organic matter, which eventually forms calcium carbonate, the substance that makes up seashells.
Significance of the Cycle
The carbon molecules cycle between the ocean and atmosphere through both physical and biological processes. The rate of CO2 diffusion depends on the concentration difference between the air and water. Atmospheric CO2 pressure drives the diffusion of carbon molecules into the ocean, maintaining a dynamic balance.
Ocean Acidification
When atmospheric CO2 levels increase, more carbon diffuses into the ocean until equilibrium is reached. Phytoplankton also absorb CO2 for photosynthesis. However, excessive CO2 lowers the ocean’s pH, making waters more acidic—a process known as ocean acidification. This has widespread consequences for marine life and ecosystems.
Conclusion
Nearly half of the oxygen we breathe comes from the oceans. Climate change and rising CO2 levels threaten the delicate carbon cycle, affecting circulation, biogeochemical processes, and marine ecosystems. Scientists continue to study how these changes will impact the balance of life in the oceans.
