Skip to main content Accessibility help
×
Home

Oceanic Radiocarbon Between Antarctica and South Africa Along Woce Section 16 at 30°E

  • Viviane Leboucher (a1), James Orr (a2), Philippe Jean-Baptiste (a2), Maurice Arnold (a1), Patrick Monfray (a1), Nadine Tisnerat-Laborde (a1), Alain Poisson (a3) and Jean-Claude Duplessy (a1)...

Abstract

Accelerator mass spectrometry (AMS) radiocarbon measurements were made on 120 samples collected between Antarctica and South Africa along 30°E during the WOCE-France CIVA1 campaign in February 1993. Our principal objective was to complement the Southern Ocean's sparse existing data set in order to improve the 14C benchmark used for validating ocean carbon-cycle models, which disagree considerably in this region. Measured 14C is consistent with the θ-S characteristics of CIVA1. Antarctic Intermediate Water (AAIW) forming north of the Polar Front (PF) is rich in 14C, whereas surface waters south of the PF are depleted in 14C. A distinct old 14C signal was found for the contribution of the Pacific Deep Water (PDW) to the return flow of Circumpolar Deep Waters (CDW). Comparison to previous measurements shows a 14C decrease in surface waters, consistent with northward displacement of surface waters, replacement by old deep waters upwelled at the Antarctic Divergence, and atmospheric decline in 14C. Conversely, an increase was found in deeper layers, in the AAIW. Large uncertainties, associated with previous methods for separating natural and bomb 14C when in the Southern Ocean south of 45°S, motivated us to develop a new approach that relies on a simple mixing model and on chlorofluorocarbon (CFC) measurements also taken during CIVA1. This approach leads to inventories for CIVA1 that are equal to or higher than those calculated with previous methods. Differences between old and new methods are especially high south of approximately 55°S, where bomb 14C inventories are relatively modest.

    • Send article to Kindle

      To send this article to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle.

      Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

      Find out more about the Kindle Personal Document Service.

      Oceanic Radiocarbon Between Antarctica and South Africa Along Woce Section 16 at 30°E
      Available formats
      ×

      Send article to Dropbox

      To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Dropbox.

      Oceanic Radiocarbon Between Antarctica and South Africa Along Woce Section 16 at 30°E
      Available formats
      ×

      Send article to Google Drive

      To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Google Drive.

      Oceanic Radiocarbon Between Antarctica and South Africa Along Woce Section 16 at 30°E
      Available formats
      ×

Copyright

References

Hide All
Andrié, C, Jean-Baptiste, P, Merlivat, L. 1986. Tritium and Helium-3 in the northeastern Atlantic Ocean during the 1983 topogulf cruise. Journal of Geophysical Research 93:12511–24.
A-S, Archambeau, Pierre, C, Poisson, A, Schauer, B. 1998. Distributions of oxygen and carbon stable isotopes and CFC-12 in the water masses of the Southern Ocean at 30°E from South Africa to Antarctica: results of the CIVA1 cruise. Journal of Marine Systems 17:25–38.
Arnold, M, Bard, E, Maurice, P, Duplessy, J-C. 1987. 14C dating with the Gif-Sur-Yvette Tandetron Accelerator: status report. Nuclear Instruments and Methods in Physics Research B29:120–3.
Bard, E. 1988. Correction of AMS 14C ages measured in planktonic foraminifera: paleoceanographic implications. Paleoceanography 3:635–45.
Bard, E, Arnold, M, Maurice, P, Duplessy, J-C 1987 Measurements of bomb radiocarbon in the ocean by means of accelerator mass spectrometry: technical aspects. Nuclear Instruments and Methods in Physics Research B29:297–301.
Bard, E, Arnold, M, Östlund, HG, Maurice, P, Monfray, P, Duplessy, J-C. 1988. Penetration of bomb radiocarbon in the tropical Indian Ocean measured by means of accelerator mass spectrometry. Earth and Planetary Science Letters 87:379–89.
Bayer, R, Schlosser, P. 1991. Tritium profiles in the Weddell Sea. Marine Chemistry 35:123–36.
Berkman, PA, Forman, SL. 1996. Pre-bomb radiocarbon and the reservoir correction for calcareous marine species in the Southern Ocean. Geophysical Research Letters 23:363–6.
Broecker, WS, Peng, TH. 1974. Gas exchange rates between air and sea. Tellus 26:21–35.
Broecker, WS, T-H, Peng, Östlund, G, Stuiver, M. 1985. The distribution of bomb radiocarbon in the ocean. Journal of Geophysical Research 90:6953–70.
Broecker, WS, Sutherland, S, Smethie, W, Peng, TH, Östlund, G. 1995. Oceanic radiocarbon: separation of the natural and bomb components. Global Biogeochemical Cycles 9:263–88.
Carmack, EC, Foster, TD. 1977. Water masses and circulation in the Weddell Sea. In: Dunbar, MJ, editor. Polar oceans. Calgary: Arctic Institute of North America. p 151–65.
Foster, TD, Carmack, EC. 1976. Frontal zone mixing and Antarctic bottom water formation in the southern Weddell Sea. Deep-Sea Research 23:301–17.
Gordon, AL. 1971. Antarctic polar front zone. In: Reid, JL, editor. Antarctic Oceanology I, Antarctic research series. Washington: American Geophysical Union. p 205–21.
Haine, TWN. 1996. Combining passive tracer observations with ocean circulation models. International WOCE Newsletter 23:3–5.
Jean-Baptiste, P, Mantisi, F, Mémery, L, Jamous, D. 1991. 3He and chlorofluorocarbons (CFC) in the Southern Ocean: tracers of water masses. Marine Chemistry 35:137–50.
Jenkins, WJ. 1980. Tritium and 3He in the Sargasso Sea. Journal of Marine Research 38: 533–69.
Key, RM, Quay, PD, Jones, GA, McNichol, AP, Von Reden, KF, Schneider, RJ. 1996. WOCE AMS Radiocarbon I: Pacific Ocean results (P6, P16, P17). Radiocarbon 38(3):425–518.
Maier-Reimer, E. 1993. Geochemical cycles in an ocean general circulation model preindustrial tracer distributions. Global Biogeochemical Cycles 7:645–77.
Mensch, M, Bayer, R, Bullister, JL, Schlosser, P, Weiss, RF. 1996. The distribution of tritium and CFCs in the Weddell Sea during the mid-1980s. Progress in Oceanography 38:377–415.
Orr, JC. 1996. The ocean carbon-cycle model intercomparison project of IGBP/GAIM. In: Ormerod, B, editor. International Energy Agency, ocean storage of CO 2 workshop 3: international links and concerns (ISBN 1 89 83 73 04 3). Southampton, England.
Orsi, AH, Nowlin, WD, Whitworth, T III. 1993. On the circulation and stratification on the Weddell Gyre. Deep-Sea Research 40:169–203.
Orsi, AH, Whitworth, T III, Nowlin, WD. 1995. On the meridional extent and fronts of the Antarctic Circumpolar Current. Deep-Sea Research 42:641–73.
Östlund, HG, Grall, C. 1988. INDIGO 1985–1987 Indian Ocean radiocarbon: tritium laboratory data report. University of Miami: Rosenstiel School of Marine and Atmospheric Science.
Östlund, HG, Stuiver, M. 1980. GEOSECS Pacific radiocarbon. Radiocarbon 22(1):25–53.
Poisson, A, Chen, C-TA. 1987. Why is there little anthropogenic CO2 in the Antarctic bottom water? Deep-Sea Research 34:1255–75.
Sarmiento, JL, Orr, JC, Siegenthaler, U. 1992. A perturbation simulation of CO2 uptake in an ocean general circulation model. Journal of Geophysical Research 97:3621–45.
Schlosser, P, Bullister, JL, Bayer, R. 1991. Studies of deep water formation and circulation in the Weddell Sea using natural and anthropogenic tracers. Marine Chemistry 35:97–122.
Schlosser, P, Kromer, B, Weppernig, R, Loosli, HH, Bayer, R, Bonani, G, Suter, M. 1994. The distribution of 14C and 39Ar in the Weddell Sea. Journal of Geophysical Research 99:10275–87.
Stuiver, M, Östlund, HG. 1980. GEOSECS Atlantic radiocarbon. Radiocarbon 22:1–24.
Stuiver, M, Östlund, HG. 1983. GEOSECS Indian Ocean and Mediterranean radiocarbon. Radiocarbon 25(1):1–29.
Stuiver, M, Östlund, HG, McConnauqhey, TA. 1981. GEOSECS Atlantic and Pacific 14C distribution. In: Bolin, B, editor. Carbon cycle modeling. New York: John Wiley & Sons. p. 201–9.
Stuiver, M, Polach, HA. 1977. Reporting of 14C data. Radiocarbon 19(3):355–63.
Taylor, NK. 1995. Seasonal uptake of anthropogenic CO2 in a ocean general circulation model. Tellus 47B:145–69.
Toggweiler, JR, Dixon, K, Bryan, K. 1989a. Simulations of radiocarbon in a coarse-resolution world ocean modelA. 1. Steady state prebomb distributions. Journal of Geophysical Research 94:8217–42.
Toggweiler, JR, Dixon, K, Bryan, K. 1989b. Simulations of radiocarbon in a coarse-resolution world ocean model. 2. Distributions of bomb-produced carbon 14. Journal of Geophysical Research 94:8243–64.
Toggweiler, JR, Samuels, B. 1993. New radiocarbon constraints on the upwelling of abyssal water to the ocean's surface. In: Heimann, M, editor. The global carbon cycle. Berlin: NATO ASI Series. p 333–66.
Toggweiler, JR, Wallace, D. 1995. Transport capacity for passive tracers. US WOCE Report 1995. p 36–8.
Warner, MJ, Weiss, RF. 1985. Solubilities of chlorofluorocarbons 11 and 12 in water and seawater. Deep-Sea Research 32:1485–97.
Weiss, RF, Östlund, HG, Craig, H. 1979. Geochemical studies of the Weddell Sea. Deep-Sea Research 26A:1093–120.
Weppernig, R, Schlosser, P, Khatiwala, S, Fairbanks, RG. 1996. Isotope data from Ice Station Weddell: implications for deep water formation in the Weddell Sea. Journal of Geophysical Research 101:25723–39.
Whitworth, T III, Nowlin, WD. 1987. Water masses and currents of the southern ocean at the Greenwich Meridian. Journal of Geophysical Research 92:6462–76.
Worthington, LV. 1977. The case for near-zero production of Antarctic bottom water. Geochimica Cosmochima Acta 41:1001–6.
Wunsch, C, Hu, DX, Grant, B. 1983. Mass, heat, salt, and nutrients fluxes in the South Pacific Ocean. Journal of Physical Oceanography 13: 725753.

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed