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Recent evidence for a strengthening CO 2 sink in the Southern Ocean from carbonate system measurements in the Drake Passage (2002–2015)
Author(s) -
Munro David R.,
Lovenduski Nicole S.,
Takahashi Taro,
Stephens Britton B.,
Newberger Timothy,
Sweeney Colm
Publication year - 2015
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2015gl065194
Subject(s) - aragonite , sink (geography) , carbonate , polar front , polar , environmental science , atmospheric sciences , climatology , oceanography , geology , chemistry , geography , physics , cartography , organic chemistry , astronomy
We present a 13 year (2002–2015) semimonthly time series of the partial pressure of CO 2 in surface water ( p CO 2surf ) and other carbonate system parameters from the Drake Passage. This record shows a clear increase in the magnitude of the sea‐air p CO 2 gradient, indicating strengthening of the CO 2 sink in agreement with recent large‐scale analyses of the world oceans. The rate of increase in p CO 2surf north of the Antarctic Polar Front (APF) is similar to the atmospheric p CO 2 ( p CO 2atm ) trend, whereas the p CO 2surf increase south of the APF is slower than the p CO 2atm trend. The high‐frequency surface observations indicate that an absence of a winter increase in total CO 2 (TCO 2 ) and cooling summer sea surface temperatures are largely responsible for increasing CO 2 uptake south of the APF. Muted winter trends in surface TCO 2 also provide temporary stability to the carbonate system that is already close to undersaturation with respect to aragonite.