Data Series 748
Carbon dioxide (CO2) in the atmosphere is absorbed at the surface of the ocean by reacting with seawater to form a weak, naturally occurring acid called carbonic acid. As atmospheric carbon dioxide increases, the concentration of carbonic acid in seawater also increases, causing a decrease in ocean pH and carbonate mineral saturation states, a process known as ocean acidification. The oceans have absorbed approximately 525 billion tons of carbon dioxide from the atmosphere, or about one-quarter to one-third of the anthropogenic carbon emissions released since the beginning of the Industrial Revolution (Sabine and others, 2004). Global surveys of ocean chemistry have revealed that seawater pH has decreased by about 0.1 units (from a pH of 8.2 to 8.1) since the 1700s due to absorption of carbon dioxide (Caldeira and Wickett, 2003; Orr and others, 2005; Raven and others, 2005). Modeling studies, based on Intergovernmental Panel on Climate Change (IPCC) CO2 emission scenarios, predict that atmospheric carbon dioxide levels could reach more than 500 parts per million (ppm) by the middle of this century and 800 ppm by the year 2100, causing an additional decrease in surface water pH of 0.3 pH units. Ocean acidification is a global threat and is already having profound and deleterious effects on the geology, biology, chemistry, and socioeconomic resources of coastal and marine habitats (Raven and others, 2005; Ruttiman, 2006). The polar and sub-polar seas have been identified as the bellwethers for global ocean acidification.
First posted May 17, 2013
For additional information contact:
Part or all of this report is presented in Portable Document Format (PDF); the latest version of Adobe Reader or similar software is required to view it. Download the latest version of Adobe Reader, free of charge.
Robbins, L.L., Yates, K.K., Knorr, P.O., Wynn, Jonathan, Lisle, John, Buczkowski, Brian, Moore, Barbara, Mayer, Larry, Armstrong, Andrew, Byrne, R.H., and Liu, Xuewu, 2013, USGS Arctic Ocean carbon cruise 2011 (ver. 1.1, April 2014): Field activity H-01-11-AR to collect carbon data in the Arctic Ocean, August - September 2011: U.S. Geological Survey Data Series 748, 1 CD. (Also available at http://pubs.usgs.gov/ds/748.)
Healy 2011 Cruise
Overview of Data Collected