Final answer:
Increased acidity in ocean water inhibits shell formation in marine organisms by preventing the proper absorption of calcium and carbonate ions necessary for constructing shells of calcium carbonate.
Step-by-step explanation:
Shells may not reform as quickly or efficiently in waters with high acidity because the increased hydrogen ion (H*) concentration in more acidic oceans inhibits the absorption of calcium and carbonate ions (CO3²-), which are critical for shell-building organisms. These organisms, such as mollusks and pteropods, rely on the equilibrium of calcium carbonate for shell formation. An environment with elevated levels of CO₂ leads to ocean acidification, and consequently, a decrease in aragonite saturation, making the formation of calcium carbonate shells more difficult. This disruption impacts the base of the food chain and has wider implications on marine ecosystems.
The buildup of acidity in ocean waters is indeed affecting organisms that construct their exoskeletons from calcium carbonate, such as corals, shellfish, and certain algae. The excess of H* blocks crucial steps in the chemistry of shell formation, resulting in reduced ability for these species to maintain or form their protective shells. This leads to increased vulnerability and may affect the survival of these organisms.