Decadal (1994-2008) change in the carbon isotope ratio in the eastern South Pacific Ocean
SCIE
SCOPUS
- Title
- Decadal (1994-2008) change in the carbon isotope ratio in the eastern South Pacific Ocean
- Authors
- Ko, YH; Lee, K; Quay, PD; Feely, RA
- Date Issued
- 2014-08
- Publisher
- AMER GEOPHYSICAL UNION
- Abstract
- We determined the 14year change in the anthropogenic CO2 inventory in the eastern South Pacific Ocean along the 110 degrees W meridian from 67 degrees S to 21 degrees N, using seawater C-13 data sets collected in 1994 and 2008. The vertical integral of the 14year C-13 change was assessed in five latitude bands and found to be greatest (-14.7myr(-1)) in the subpolar band (38 degrees S-55 degrees S) and smallest (-3.0myr(-1)) in the tropical band (21 degrees N-18 degrees S). The C-13 change in each of the latitudinal bands was primarily caused by inputs of anthropogenic CO2 via air-sea exchange and transport. More than 50% of the total anthropogenic CO2 was added to the subpolar band via the northward movement of Antarctic Intermediate Water (AAIW) from the south, and the remaining 50% was added via air-sea exchange. We also calculated the ratio of the temporal change in C-13 to the change in dissolved inorganic carbon, which is a measure of the efficiency of oceanic uptake of anthropogenic CO2. The ratio for AAIW in 1994 (-0.017 parts per thousand (mu molkg(-1)) (-1)) was greater than that in 2008 (-0.010 parts per thousand (mu molkg(-1)) (-1)) based on the change in preformed C-13 and dissolved inorganic carbon (DIC), indicating reduced efficiency of CO2 uptake by the Southern Ocean in 2008 relative to that in 1994. AAIW remained at the surface for a shorter period in 2008 relative to 1994, and thus would have taken up less atmospheric CO2 prior to subduction. The projected reduction in this ratio indicates a weakening of CO2 uptake by the Southern Ocean in the future.
- Keywords
- carbon isotope; anthropogenic carbon dioxide; NORTH-ATLANTIC OCEAN; ANTHROPOGENIC CO2; ANNULAR MODE; DELTA-C-13; DIOXIDE; MARINE; DEPTH; CYCLE; SINK
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/14284
- DOI
- 10.1002/2013GB004786
- ISSN
- 0886-6236
- Article Type
- Article
- Citation
- GLOBAL BIOGEOCHEMICAL CYCLES, vol. 28, no. 8, page. 775 - 785, 2014-08
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