Oceanic Carbon Cycle
The oceanic carbon cycle refers to the continuous movement and exchange of carbon among the ocean, atmosphere, marine organisms, and seafloor. Oceans absorb atmospheric carbon dioxide, store it as dissolved carbon, and convert it through biological processes like photosynthesis by phytoplankton. Marine organisms use this carbon, and when they die, some carbon sinks to the ocean floor. This cycle helps regulate Earth’s climate by controlling atmospheric carbon dioxide levels.
Oceanic Carbon Cycle
The oceanic carbon cycle refers to the continuous movement and exchange of carbon among the ocean, atmosphere, marine organisms, and seafloor. Oceans absorb atmospheric carbon dioxide, store it as dissolved carbon, and convert it through biological processes like photosynthesis by phytoplankton. Marine organisms use this carbon, and when they die, some carbon sinks to the ocean floor. This cycle helps regulate Earth’s climate by controlling atmospheric carbon dioxide levels.
💡 Key Takeaways
- Describe how the ocean exchanges CO2 with the atmosphere and acts as a carbon sink.
- Identify the major ocean carbon pools: dissolved inorganic carbon, organic carbon, and carbonate minerals.
- Explain the biological carbon pump and how carbon moves from surface waters to deep ocean and sediments.
- Understand how temperature, circulation, and acidification affect carbon storage and carbonate chemistry.
❓ Frequently Asked Questions
What is the oceanic carbon cycle?
The system of processes that move carbon among the atmosphere, surface and deep ocean, marine life, and sediments, including gas exchange, photosynthesis, respiration, decay, and sedimentation.
How does carbon enter and leave the surface ocean?
Carbon enters by CO2 dissolving from the air and by phytoplankton photosynthesis; it leaves by respiration and decay, upwelling of deep carbon, and outgassing back to the atmosphere. The solubility pump also transports CO2 to the deep ocean as cold water sinks.
What is the biological carbon pump?
Phytoplankton fix CO2 into organic matter; when they die or are consumed, some carbon-rich particles sink to the deep ocean, sequestering carbon away from the atmosphere for long times.
How do carbonate chemistry and alkalinity affect the cycle?
Calcium carbonate shells and carbonate minerals regulate alkalinity and pH; their formation and dissolution store carbon in sediments and influence how much CO2 the ocean can absorb.