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Images: The Socioeconomic Costs of Ocean Acidification

Model-calculated aragonite saturation states throughout the surface ocean in 2000, 2050, and 2099. Aragonite is a form of calcium carbonate often used by calcifying organisms to create shells and skeletons. Saturation state measures the amount of calcium and carbonate, the mineral building blocks of aragonite, present in the water. In areas where the aragonite saturation state is below 1 (shades of red), most exposed aragonite structures will dissolve. However, the growth of calcifying organisms may decrease with declining saturation state, even if it remains above 1. This model predicts that as ocean acidification continues over the next 90 years, surface aragonite saturation states will drop throughout the global oceans. By 2099, only tropical and subtropical waters may have saturation levels high enough to support the growth of calcifying organisms such as some mollusks, crustaceans, and corals.

Surface values were calculated with the Community Climate System Model 3.1 of the National Center for Atmospheric Research.

(Richard A. Feely, Scott C. Doney, and Sarah R. Cooley, 2009, Oceanography 22:36-47)

In 2007, first-sale revenues from U.S. commercial fisheries totaled about $4 billion. Four groups of animals contributed almost equally to that total. Two groups are calcifiers, which means they make shells, spines, or exoskeletons out of calcium carbonate: crustaceans (lobsters, crabs, shrimp) and mollusks (clams, oysters, mussels, scallops, and other non-crustacean calcifiers). The other two groups are animals that prey on calcifiers (such as flounder and octopus) and top predators that eat the calcifiers’ predators (such as salmon and tuna). Of these groups, the mollusks appear most vulnerable to direct effects of ocean acidification. But a decline in those species could cause problems for predators above them on the food chain.

Sarah Cooley, a postdoctoral researcher in the Marine Chemistry and Geochemistry Department at Woods Hole Oceanographic Institution, is working to assess the possible socioeconomic threats posed by ocean acidification.