Final answer:
Carbon dioxide is stored effectively in ocean water as it dissolves and reacts with water to form carbonate ions, which then combine with calcium to create calcium carbonate, accumulating in marine sediments and forming large carbon reservoirs.
Step-by-step explanation:
Carbon dioxide is able to be stored more effectively in ocean water as compared to freshwater due to several chemical processes that occur in the ocean. When carbon dioxide (CO₂) from the atmosphere dissolves in water, it forms carbonic acid, which further ionizes to create carbonate and bicarbonate ions.
These ions can combine with calcium ions present in seawater to form calcium carbonate (CaCO₃), which is a significant component of marine organism shells. These shells accumulate on the ocean floor as sediments and over time can transform into limestone, creating a substantial carbon reservoir. Additionally, the ocean's ability to store carbon is influenced by the continuous cycling of carbon through processes such as photosynthesis, respiration, and the sedimentation of organic material.