Climate & Ocean Acidification

This week (April 10-17, 2011) is National Environmental Education Week, the nation’s largest environmental education event held each year the week before Earth Day to inspire environmental learning and stewardship among students and the public.

This year’s EE Week theme is Ocean Connections, highlighting that no matter how far from the coast, water in every stream or river ends up in the ocean. The oceans impact weather and climate, house a vast array of wildlife and provide 70 percent of the oxygen on earth.

To celebrate EE Week, we will provide daily “Ocean Connections” information and tips.

Today's Topic.... Climate & Ocean Acidification

More acidic waters mean there are fewer carbonate molecules in the water available to the organisms that build their bodies out of calcium carbonate, such as coral, oysters and tiny plankton. All of these organisms are crucial for the health of ocean ecosystems that provide the fish that humans eat. Did you know…

• The oceans are currently absorbing about 22 million tons of carbon dioxide (CO2) each day.
• The oceans have absorbed an estimated 525 billion tons of CO2 over the last 200 years.
• As oceans take CO2 out of the atmosphere, the waters become more acidic.
• On the pH acidity scale (which ranges from zero to 14, with zero being the most acidic and seven being neutral) the world’s oceans have fallen from a pH of 8.2 in the late 18th century to a pH of 8.1 today, a 30 percent increase in acidity.
• The tiny planktonic foraminifera that live in the Southern Ocean around Antarctic have shells that are now one-third thinner than they were in pre-industrial times.

(Sources: Hoegh-Guldberg et al. “Coral Reefs Under Rapid Climate Change and Ocean Acidification.” Science 318 (2007): 1737 and “Oceans Becoming More Acidic, Potentially Threatening Marine Life.” Science Daily 23 February 2009. Accessed Online 25 February 2009 <http://www.sciencedaily.com/releases/2009/02/090223091752.htm> and Moy, AD et al. “Reduced calcification in modern Southern Ocean planktonic foraminifera.” Nature Geoscience 2 (2009): doi:10.1038/ngeo460.)