The decline of marine ecosystems due to ocean acidification can have significant economic consequences. Fisheries, tourism, and coastal communities rely on healthy oceans for their livelihoods, and the loss of marine resources can have devastating effects on these industries. 

Many marine organisms, such as corals, oysters, and clams, rely on calcium carbonate to build their shells or skeletons. As the ocean becomes more acidic, the availability of carbonate ions decreases, making it difficult for these organisms to construct and maintain their protective structures. In extreme cases, their shells can even dissolve. 

Ocean acidification can threaten the survival of numerous marine species, contributing to a loss of biodiversity. As species struggle to adapt to the changing conditions, their populations may decline or even become extinct. 

The decline of shell-building organisms can have cascading effects on marine food webs. These organisms are often at the base of the food chain, providing sustenance for a variety of other species. Their decline can lead to disruptions in the entire ecosystem, affecting fish populations and other marine life.