Climate Trivia: Ocean Acidification
The oceans are currently absorbing about 22 million tons of carbon dioxide (CO2) each day and have absorbed an estimated 525 billion tons of CO2 over the last 200 years.
Trivia Question: As the oceans absorb more carbon dioxide, they become…
a. more basic (higher pH).
b. more acidic (lower pH).
c. richer in nutrients.
d. warmer.
The correct answer is b. As oceans take CO2 out of the atmosphere, the waters become more acidic. More acidic waters mean there are less carbonate molecules available to organisms that use calcium carbonate to build their bodies, such as coral, oysters and many of the tiny plankton that are at the base of the food chain. One indicator of how this acidification has affected ocean life is the thickness of foraminiferan shells, which are a type of plankton. Samples from the Southern Ocean around Antarctica indicate that foramineferan shells, which are harder to make when there are fewer carbonate molecules, are now one-third thinner than they were in pre-industrial times.
Seasons: Winter, Spring, Summer, Fall
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
