Carbon tetrachloride and chlorofluorocarbons in the South Atlantic Ocean, 19{degrees}S
- Brookhaven National Lab., Upton, NY (United States)
- Univ. of Bremen (Germany)
Exploratory measurements of a suite of anthropogenic halocarbon compounds (CCl{sub 4}, CCl{sub 2}FCClF{sub 2} (CFC-113), CH{sub 3}CCl{sub 3}, CCl{sub 3}F (CFC-11)) were made using a new analytical technique on RV Meteor cruise 15 along 19{degrees}S (World Ocean Circulation Experiment (WOCE) Line A9) in the Atlantic Ocean during February-March 1991. A separate analytical system was used to determine CCl{sub 2}F{sub 2} (CFC-12) and CCl{sub 3}F (CFC-11). A limited number of CFC-113 profiles indicated that it was undetectable below 400-500 m. The CCl{sub 4} data indicate that the entire Brazil Basin contains readily measurable levels of CCl{sub 4}(>0.05 pmol kg{sup {minus}1}), whereas the deep Angola Basin contains very low levels ({le}0.02 pmol kg{sup {minus}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 CCl{sub 4} in the atmosphere were therefore negligible (atmospheric mixing ratio <0.1 pptv). CCl{sub 4}/CFC-11 ratios are used to estimate apparent ages and dilution factors for the North Atlantic Deep Water and Antarctic Bottom Water. Whereas CCl{sub 4}/CFC-11/CFC-12 levels are internally consistent in deep waters, suggesting near-conservative behavior, there is evidence for very rapid removal of CCl{sub 4} in the thermocline. Removal rates suggest that in addition to neutral hydrolysis, some other loss pathway must be involved. 43 refs., 11 figs.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 166251
- Journal Information:
- Journal of Geophysical Research, Vol. 99, Issue C4; Other Information: PBD: 15 Apr 1994
- Country of Publication:
- United States
- Language:
- English
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