Answer:
Carbon, in nature, can be found in four main pool: atmosphere, oceans, soil and living organisms. Scientist say that the oceans are the largest reservoir of carbon in the world.
There are several ways in which the carbon enters the ocean:
- rivers on their way to the ocean dissolve rocks and sediments, releasing carbon, carrying it further
- atmospheric carbon dioxide can react with the droplets of water in clouds, forming acid, which then via rain can fall into the ocean
- since oceans are in direct contact with air and atmospheric carbon dioxide, they can be mixed together with the help of wind and waves, thus dissolving CO₂ in the ocean
- marine organisms, such as algae, plankton and ocean plant are performing photosynthesis, in which huge amounts of CO₂ are being released into the ocean
- some of the CO₂ created in photosynthesis gets used by these organisms to produce complex compounds incorporated in their cells, which will be transferred to other ocean animals via the food chain
Among all these and many more ways of the carbon entering oceans, photosynthesis and CO₂ dissolving are the two most important.