Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms

Thumbnail Image
Orr, James C.
Fabry, Victoria J.
Aumont, Olivier
Bopp, Laurent
Doney, Scott C.
Feely, Richard A.
Gnanadesikan, Anand
Gruber, Nicolas
Ishida, Akio
Joos, Fortunat
Key, Robert M.
Lindsay, Keith
Maier-Reimer, Ernst
Matear, Richard J.
Monfray, Patrick
Mouchet, Anne
Najjar, Raymond G.
Plattner, Gian-Kasper
Rodgers, Keith B.
Sabine, Christopher L.
Sarmiento, Jorge L.
Schlitzer, Reiner
Slater, Richard D.
Totterdell, Ian J.
Weirig, Marie-France
Yamanaka, Yasuhiro
Yool, Andrew
Alternative Title
Anthropogenic Decline in High-Latitude Ocean Carbonate by 2100
Date Created
Replaced By
The surface ocean is everywhere saturated with respect to calcium carbonate (CaCO3). Yet increasing atmospheric CO2 reduces ocean pH and carbonate ion concentrations [CO32−] and thus the level of saturation. Reduced saturation states are expected to affect marine calcifiers even though it has been estimated that all surface waters will remain saturated for centuries. Here we show, however, that some surface waters will become undersaturated within decades. When atmospheric CO2 reaches 550 ppmv, in year 2050 under the IS92a business-as-usual scenario, Southern Ocean surface waters begin to become undersaturated with respect to aragonite, a metastable form of CaCO3. By 2100 as atmospheric CO2 reaches 788 ppmv, undersaturation extends throughout the entire Southern Ocean (< 60°S) and into the subarctic Pacific. These changes will threaten high-latitude aragonite secreting organisms including cold-water corals, which provide essential fish habitat, and shelled pteropods, an abundant food source for marine predators.
Author Posting. © The Authors, 2005. This is the author's version of the work. It is posted here by permission of Nature Publishing Group for personal use, not for redistribution. The definitive version was published in Nature 437 (2005): 681-686, doi:10.1038/nature04095.
Embargo Date
Cruise ID
Cruise DOI
Vessel Name