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Monitoring Ocean Acidification

Pacific Coral. (file)

Changes in the chemistry of the world's oceans, due to an excess of atmospheric carbon dioxide, creates higher acidity in the oceans.

For more than 3 decades, scientists at the U.S. Department of Commerce's National Oceanic and Atmospheric Administration, or NOAA, have been studying a growing global problem: changes in the chemistry of the world's oceans due to an excess of atmospheric carbon dioxide which make the oceans more acidic. The process is called "ocean acidification" and researchers are now finding evidence of this change in U.S. coastal waterways.

Approximately 30 percent of all carbon dioxide released into the atmosphere is absorbed by the ocean. While this removes some of this greenhouse gas from the atmosphere, there is a problem: When carbon dioxide reacts with seawater, it forms carbonic acid, which changes ocean chemistry in 2 fundamental ways. First, carbonic acid releases hydrogen ions, making the ocean more acidic. Changes in the ocean’s acidity will have profound effects on both individual organisms and ecosystems, many of which will be unpredictable and irreversible on any meaningful timeframe. Second, the acid produced by carbonic acid removes carbonate ions, an essential building block for the shells of many marine organisms such as corals, marine plankton, and shellfish. Combined, these changes stand to have fundamental affects on marine food webs.

Coastal estuaries and waterways are also threatened by acidification. Recently, scientists at NOAA's Pacific Marine Environmental Laboratory, or PMEL, and the University of Washington documented acidification of the waters of the Puget Sound. Dr. Richard Feely of PMEL noted that the subsurface water of the Puget Sound's Hood canal were 200 percent more acidic than open ocean surface waters which may be responsible for recent massive die-offs of oyster larvae.

This is cause for concern for Washington state shellfish industries, which produce more than $100 million in revenues. NOAA, in cooperation with the University of Washington, and the Northwest Association of Networked Ocean Observing Systems, is measuring carbon dioxide in the air and subsurface waters of Washington's coast and changes in acidification. PMEL also collaborates with biologists in other divisions of NOAA, academia, and other state and federal agencies to help them learn about the impacts of ocean acidification on ecosystems.

The U.S. Government, through the research of NOAA and other U.S. agencies and the external research programs funded by the National Science Foundation, will continue to work with its partners to research and monitor ocean acidification at the local and global level. It is essential to better understand the long term consequences of ocean acidification.