Which statement best describes ocean acidification and its chemical mechanism?

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Ocean acidification arises from the chemistry of how seawater interacts with carbon dioxide in the atmosphere. When CO2 dissolves in seawater, it reacts with water to form carbonic acid. Carbonic acid then dissociates, releasing hydrogen ions and bicarbonate. The extra hydrogen ions raise the acidity (lower the pH) of the ocean. This shift also reduces the concentration of carbonate ions, which many marine organisms need to build shells and skeletons, making calcification more difficult. The other statements don’t describe acidification: a temperature change from currents affects heat, not pH; more dissolved oxygen from photosynthesis relates to oxygen content, not acidity; higher salinity from evaporation changes salinity, not the hydrogen ion concentration.