Formulate the main reactions that contribute to the ocean's buffering capacity, and discuss how the reaction proceeds. What will be an ideal response?

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When dissolved in water CO2 is present in several different forms: carbonic acid (H2CO3),
the bicarbonate ion (HCO3-), and the carbonate ion (CO32-), including the release of
hydrogen ions (H+) as these constituents breakdown.
Step One: CO2 + H2O <=> H2CO3
Step Two: H2CO3 <=> HCO3- + H+
Step Three: HCO3- + H+ <=> CO32- + 2H+
In Step One, carbon dioxide and water combine to form carbonic acid. Carbonic acid rapidly
dissociates into a bicarbonate ion (HCO3-) and a hydrogen ion (H+) in Step Two. Most of the
CO2 dissolved in seawater ends up as HCO3-. Some of the bicarbonate and hydrogen ions
will then combine to form carbonate (CO32-) ions and two hydrogen ions (2H+) in Step
Three. At any given pH CO2, H2CO3, HCO3-, CO32- and H+ exist in equilibrium with each
other. If acid is added to the system and pH decreases, the reaction proceeds toward Step One
(to the left), raising the pH by removing excess H+ ions. If an alkaline solution is added, and the pH increases, the reaction proceeds toward Step Three (to the right), lowering the pH by
releasing H+ ions.