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Ocean Acidification Increasing at Unprecedented Rate

Ocean acidification is increasing at an unprecedented rate, according to a study published in August 2013 in Nature. As oceans absorb carbon dioxide (CO2) emitted to the atmosphere by human causes, the increase in inorganic carbon concentrations results in decreased pH levels and calcium carbonate saturation. This phenomenon, called ocean acidification, is different from, and many believe more dangerous than, the more publicized warming effects of CO2 emissions. These changes impact all ocean life.

Rising ocean acidity has the greatest immediate impact on shellfish. But impacts on shellfish have effects along the entire oceanic food chain. As creatures with calcium shells become scarce, or disappear, their predators will either become more scarce or must adapt by seeking other food sources.

Among the invertebrates, corals, echinoderms and mollusks suffer the most, whereas crustaceans appear to be relatively resistant. Impacts of acidification on fish populations are less clear. The authors conclude that the diversity of responses could lead to profoundly altered ecosystems in the future.

Along with decreasing the food supply of other sea creatures, ocean acidification also threatens to disrupt human food supply chains. Globally, over a billion people rely on the ocean as their primary food source.

Source: Astrid C. Wittmann & Hans-O. Pörtner, “Sensitivities of Extant Animal Taxa to Ocean Acidification,” Nature, August 26, 2013, http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate1982.html.
Student Researcher: Amanda Baxter (Sonoma State University)
Faculty Evaluator: Elaine Wellin (Sonoma State University)