Carbon tetrachloride and chlorofluorocarbons in the South Atlantic Ocean, 19°S.

Wallace, Douglas W.R., Putzka, A. and Beining, P. (1994) Carbon tetrachloride and chlorofluorocarbons in the South Atlantic Ocean, 19°S. Open Access Journal of Geophysical Research: Oceans, 99 . pp. 7803-7819. DOI 10.1029/94JC00031.

[thumbnail of Wallace(1994).pdf]
Preview
Text
Wallace(1994).pdf - Reprinted Version

Download (19MB) | Preview

Supplementary data:

Abstract

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 (World Ocean Circulation Experiment (WOCE) Line A9)) 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.

Document Type: Article
Refereed: Yes
Open Access Journal?: No
Publisher: AGU (American Geophysical Union)
Date Deposited: 18 Feb 2008 17:27
Last Modified: 28 Nov 2017 11:29
URI: https://oceanrep.geomar.de/id/eprint/153

Actions (login required)

View Item View Item