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Detailed Reference Information |
Wallace, D.W.R., Beining, P. and Putzka, A. (1994). Carbon tetrachloride and chlorofluorocarbons in the South Atlantic Ocean, 19°S. Journal of Geophysical Research 99: doi: 10.1029/94JC00031. issn: 0148-0227. |
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Exploratory measurements of a suite of anthropogenic halocarbon compounds (CCl4, CCl2FCClF2(CFC-113), CH3CCl3, CCl3F(CFC-11) were made using a new analytical technique on RV Meteor cruise 15 along 19 ¿S in the Atlantic Ocean during February--March 1991. A separate analytical system was used to determine CCl2F2 (CFC-12) and CCl3F(CFC-11). A limited number of CFC-113 profiles indicated that it was undetectable below 400--500 m. The CCl4 data indicate that the entire Brazil Basin contains readily measurable levels of CCl4(>0.05 pmol kg-1), whereas the deep Angola Basin contains very low levels (≤0.02 pmol kg-1). Slightly higher levels were found close to the bottom in the deep Angola Basin: possibly an anthropogenic signature. In contrast, most of the deep Brazil Basin and all of the deep Angola Basin (>1000 m) had undetectable levels of CFC-11, CFC-12, and CFC-113. Preindustrial levels of CCl4 in the atmosphere were therefore negligible (atmospheric mixing ratio <0.1 pptv). CCl4/CFC-11 ratios are used to estimate apparent ages and dilution factors for the North Atlantic Deep Water and Antarctic Bottom Water. Whereas CCl4/CFC-11/CFC-12 levels are internally consistent in deep waters, suggesting near-conservative behavior, there is evidence for very rapid removal of CCl4 in the thermocline. Removal rates suggest that in addition to neutral hydrolysis, some other loss pathway must be involved. ¿ American Geophysical Union 1994 |
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Abstract |
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Keywords
Oceanography, Biological and Chemical, Geochemistry, Oceanography, General, Water masses, Oceanography, Physical, Western boundary currents, Oceanography, Physical, General circulation |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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