Sunday, May 03, 2009

Ocean Becoming More Acidic, Potentially Threatening Marine Life

ScienceDaily (Feb. 23, 2009) — A dramatic increase in carbon dioxide levels is making the world's ocean more acidic, which may adversely affect the survival of marine life and organisms that depend on them, such as humans. The article "Off Balance Ocean" is scheduled for the Feb. 23 issue of Chemical & Engineering News.

In the article, C&EN Associate Editor Rachel Petkewich notes that the increased use of fossil fuels has caused levels of carbon dioxide in the atmosphere to nearly double since the Industrial Revolution. The ocean absorbs large amounts of carbon dioxide — about 22 million tons a day — causing the water's pH to decrease or acidify. The pH scale measures how acidic or alkaline substances are. The pH scale ranges from 0 to 14. A pH of 7 is neutral. A pH less than 7 is acidic. A pH greater than 7 is alkaline. The ocean's pH is currently about 8.1, down from 8.2 in the 18th century, the article notes. Scientists project that the ocean's pH will fall by about 0.3 more units in the next 50 to 100 years.

Researchers worldwide are now reporting that these lower pH levels could affect many aspects of the biochemistry, development, and reproduction of marine organisms, including jellyfish, sea anemones, plankton, and coral. Lower pH levels may even affect the ability of the ocean to transmit sound, which could affect the way some mammals communicate by sonar, the article notes. "To what extent the oceans will continue to acidify is uncertain and whether marine organisms can adapt to the changes in store also remains to be seen," the article notes.

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