|Carbon tetrachloride and chlorofluorocarbons in the South Atlantic Ocean, 19° S|Wallace, D.W.R.; Beining, P.; Putzka, A. (1994). Carbon tetrachloride and chlorofluorocarbons in the South Atlantic Ocean, 19° S. J. Geophys. Res. 99(C4): 7803-7819. hdl.handle.net/10.1029/94JC00031
In: Journal of Geophysical Research. American Geophysical Union: Richmond. ISSN 0148-0227, more
Age; Anthropogenic factors; Atmosphere; Basins; Bottom water; Chemical pollutants; Chemical speciation; Chlorofluorocarbons; Deep water; Deep water; Deep-water masses; Halogenated hydrocarbons; Hydrolysis; Industrial wastes; Marine pollution; Mixing ratio; Ocean basins; Ocean circulation; Oceanic circulation; Oceans; Pollutant persistence; Pollution detection; Thermocline; World Ocean; Marine
|Authors|| || Top |
- Wallace, D.W.R.
- Beining, P.
- Putzka, A.
Exploratory measurements of a suite of anthropogenic halocarbon compounds (CCl4 , CCl2 FCClF2 (CFC-113), CH3 CCl 3, CCl3 F (CFC-11)) were made using a new analytical technique on RV Meteor cruise 15 along 19° S (World Ocean Circulation Experiment (WOCE) Line A9)) in the Atlantic Ocean during February-March 1991. A separate analytical system was used to determine CCl2 F 2 (CFC-12) and CCl3 F (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 (less than or equal to 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 CCl 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 4 in the thermocline. Removal rates suggest that in addition to neutral hydrolysis, some other loss pathway must be involved.