Current CaCO3 dissolution at the seafloor caused by anthropogenic CO2

Type Article
Date 2018-11
Language English
Author(s) Sulpis OlivierORCID1, 2, Boudreau Bernard P.3, Mucci AlfonsoORCID1, 2, Jenkins Chris4, Trossman David S.5, Arbic Brian K.6, Key Robert M.7
Affiliation(s) 1 : McGill Univ, GEOTOP, Montreal, PQ H3A 0E8, Canada.
2 : McGill Univ, Dept Earth & Planetary Sci, Montreal, PQ H3A 0E8, Canada.
3 : Dalhousie Univ, Dept Oceanog, Halifax, NS B3H 4R2, Canada.
4 : Univ Colorado, Inst Arctic & Alpine Res, Boulder, CO 80309 USA.
5 : Univ Texas Austin, Inst Computat Engn & Sci, Austin, TX 78712 USA.
6 : Univ Michigan, Dept Earth & Environm Sci, Ann Arbor, MI 48109 USA.
7 : Princeton Univ, Atmospher & Ocean Sci, Princeton, NJ 08540 USA.
Source Proceedings Of The National Academy Of Sciences Of The United States Of America (0027-8424) (Natl Acad Sciences), 2018-11 , Vol. 115 , N. 46 , P. 11700-11705
DOI 10.1073/pnas.1804250115
WOS© Times Cited 26
Keyword(s) ocean acidification, seafloor, CaCO3, dissolution, anthropogenic CO2
Abstract

Oceanic uptake of anthropogenic CO2 leads to decreased pH, carbonate ion concentration, and saturation state with respect to CaCO3 minerals, causing increased dissolution of these minerals at the deep seafloor. This additional dissolution will figure prominently in the neutralization of man-made CO2 . However, there has been no concerted assessment of the current extent of anthropogenic CaCO3 dissolution at the deep seafloor. Here, recent databases of bottom-water chemistry, benthic currents, and CaCO3 content of deep-sea sediments are combined with a rate model to derive the global distribution of benthic calcite dissolution rates and obtain primary confirmation of an anthropogenic component. By comparing preindustrial with present-day rates, we determine that significant anthropogenic dissolution now occurs in the western North Atlantic, amounting to 40-100% of the total seafloor dissolution at its most intense locations. At these locations, the calcite compensation depth has risen similar to 300 m. Increased benthic dissolution was also revealed at various hot spots in the southern extent of the Atlantic, Indian, and Pacific Oceans. Our findings place constraints on future predictions of ocean acidification, are consequential to the fate of benthic calcifiers, and indicate that a by-product of human activities is currently altering the geological record of the deep sea.

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Sulpis Olivier, Boudreau Bernard P., Mucci Alfonso, Jenkins Chris, Trossman David S., Arbic Brian K., Key Robert M. (2018). Current CaCO3 dissolution at the seafloor caused by anthropogenic CO2. Proceedings Of The National Academy Of Sciences Of The United States Of America, 115(46), 11700-11705. Publisher's official version : https://doi.org/10.1073/pnas.1804250115 , Open Access version : https://archimer.ifremer.fr/doc/00675/78677/