Final answer:
Ocean acidification affects marine organisms by reducing the availability of calcium carbonate, essential for their shells and skeletons. Corals are particularly at risk from declining calcification rates, which could lead to their scarcity on reefs by 2050 if carbon dioxide concentrations keep increasing.
Step-by-step explanation:
Ocean acidification is the process of ocean waters decreasing in pH. Oceans become more acidic as carbon dioxide (CO2) emissions in the atmosphere dissolve in the ocean. As ocean acidification increases, the availability of calcium carbonate will decline.
This can negatively affect marine organisms, including plankton, mollusks, shellfish, and corals, which rely on calcium carbonate for their shells and skeletons. Coral calcification rates are projected to decline by more than 30% if atmospheric CO₂ concentrations double. Corals could become rare on tropical and subtropical reefs by 2050 if CO2 concentrations continue to rise at their current rate.