Nature, 437, 681-686 (29 September 2005)

In a study done by Orr et al., the decreasing rate of free carbonate ion available for calcification for sea organisms will become undersaturated by 2050. Calcium ions in the ocean react with carbonate ions to form calcium carbonate which makes up exoskeletons of various sea organisms. The excess of dissolved carbon dioxide in the ocean has caused increasing amounts of carbonate to become tied up in bicarbonate ions which are unable to be used to form calcium carbonate. Pteropods have shown significant decreased calcification in water the same pH predicted with the “business-as-usual” projections. They are near the bottom on the food chain, and a change in their population could have a ripple effect throughout the entire ocean ecosystem. In higher altitude ocean ecosystems, this study has shown that acidification is increasing at a slower rate. This only means that these ecosystems will lag the lower altitude ones by 50-100 years. The only benefit to this is that these organisms have more time to possibly adapt to the new ocean chemistry.