Open AccessData‐based estimation of anthropogenic carbon and acidification in the Weddell Sea on a decadal timescale
Author(s) -
Hauck J.,
Hoppema M.,
Bellerby R. G. J.,
Völker C.,
WolfGladrow D.
Publication year - 2010
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2009jc005479
Subject(s) - aragonite , ocean acidification , calcite , ocean gyre , oceanography , saturation (graph theory) , surface water , weddell sea bottom water , geology , carbonate , deep sea , mesopelagic zone , seawater , environmental science , sea ice , mineralogy , chemistry , ecology , pelagic zone , biology , arctic ice pack , subtropics , mathematics , organic chemistry , combinatorics , environmental engineering , antarctic sea ice
The amount of anthropogenic CO 2 ( C ant ) that entered the Weddell Sea between 1992 and 2008 ( C ant 1992–2008 ) was assessed using the extended multiple linear regression (eMLR) method. In the Warm Deep Water (WDW) and the Weddell Sea Bottom Water (WSBW), C ant 1992–2008 values were insignificant, whereas values as high as 8 μ mol kg −1 were observed over the shelf. C ant 1992–2008 concentrations in the surface layer varied with latitude between 2 and 11 μ mol kg −1 . Weak intrusion of anthropogenic CO 2 into Weddell Sea Deep Water (WSDW) was demonstrated ( C ant 1992–2008 yields 1.5–2 μ mol kg −1 ). That more C ant 1992–2008 was found in the WSDW than in the WSBW is surprising, but can be explained by intense ventilation of the WSDW originating from east of the Weddell Gyre. The invasion of C ant 1992–2008 provokes a shift in the equilibria of the carbonate system, resulting in acidification and reduction of CO 3 2− concentration. The mean decrease of pH in the upper 200 m layer was 0.016. The largest decrease of calcite and aragonite saturation states was observed at the surface. This implies that surface waters might become undersaturated with respect to aragonite in the future while the underlying WDW is still saturated. Results of this analysis suggest that complete undersaturation of surface waters in the Weddell Sea will be reached after the 21st century.