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

Published online by Cambridge University Press:  18 July 2016

Viviane Leboucher ,
James Orr ,
Philippe Jean-Baptiste ,
Maurice Arnold ,
Patrick Monfray ,
Nadine Tisnerat-Laborde ,
Alain Poisson  and
Jean-Claude Duplessy
Viviane Leboucher
Affiliation:
Laboratoire des Sciences du Climat et de l'Environnement (LSCE), Avenue de la Terrasse, F-91198 Gif-sur-Yvette Cedex, France
James Orr
Affiliation:
Laboratoire des Sciences du Climat et de l'Environnement (LSCE), DSM/CEN Saclay/CEA, L'Orme, Bât. 709, F-91191 Gif-sur-Yvette Cedex, France
Philippe Jean-Baptiste
Affiliation:
Laboratoire des Sciences du Climat et de l'Environnement (LSCE), DSM/CEN Saclay/CEA, L'Orme, Bât. 709, F-91191 Gif-sur-Yvette Cedex, France
Maurice Arnold
Affiliation:
Laboratoire des Sciences du Climat et de l'Environnement (LSCE), Avenue de la Terrasse, F-91198 Gif-sur-Yvette Cedex, France
Patrick Monfray
Affiliation:
Laboratoire des Sciences du Climat et de l'Environnement (LSCE), Avenue de la Terrasse, F-91198 Gif-sur-Yvette Cedex, France
Nadine Tisnerat-Laborde
Affiliation:
Laboratoire des Sciences du Climat et de l'Environnement (LSCE), Avenue de la Terrasse, F-91198 Gif-sur-Yvette Cedex, France
Alain Poisson
Affiliation:
Laboratoire de Physique et Chimie Marines (LPCM), Université Pierre et Marie Curie, 4, place Jussieu, F-75252 Paris Cedex 05, France
Jean-Claude Duplessy
Affiliation:
Laboratoire des Sciences du Climat et de l'Environnement (LSCE), Avenue de la Terrasse, F-91198 Gif-sur-Yvette Cedex, France
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Abstract

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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.

Type
Articles
Information
Radiocarbon , Volume 41 , Issue 1 , 1999 , pp. 51 - 73
Copyright
Copyright © The American Journal of Science 

References

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.Google Scholar
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.Google Scholar
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.Google Scholar
Bard, E. 1988. Correction of AMS 14C ages measured in planktonic foraminifera: paleoceanographic implications. Paleoceanography 3:635–45.Google Scholar
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.Google Scholar
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.Google Scholar
Bayer, R, Schlosser, P. 1991. Tritium profiles in the Weddell Sea. Marine Chemistry 35:123–36.Google Scholar
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.Google Scholar
Broecker, WS, Peng, TH. 1974. Gas exchange rates between air and sea. Tellus 26:21–35.Google Scholar
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.CrossRefGoogle Scholar
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.Google Scholar
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.Google Scholar
Foster, TD, Carmack, EC. 1976. Frontal zone mixing and Antarctic bottom water formation in the southern Weddell Sea. Deep-Sea Research 23:301–17.Google Scholar
Gordon, AL. 1971. Antarctic polar front zone. In: Reid, JL, editor. Antarctic Oceanology I, Antarctic research series. Washington: American Geophysical Union. p 205–21.Google Scholar
Haine, TWN. 1996. Combining passive tracer observations with ocean circulation models. International WOCE Newsletter 23:3–5.Google Scholar
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.Google Scholar
Jenkins, WJ. 1980. Tritium and 3He in the Sargasso Sea. Journal of Marine Research 38: 533–69.Google Scholar
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.Google Scholar
Maier-Reimer, E. 1993. Geochemical cycles in an ocean general circulation model preindustrial tracer distributions. Global Biogeochemical Cycles 7:645–77.Google Scholar
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.Google Scholar
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.Google Scholar
Orsi, AH, Nowlin, WD, Whitworth, T III. 1993. On the circulation and stratification on the Weddell Gyre. Deep-Sea Research 40:169–203.Google Scholar
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.Google Scholar
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.Google Scholar
Östlund, HG, Stuiver, M. 1980. GEOSECS Pacific radiocarbon. Radiocarbon 22(1):25–53.Google Scholar
Poisson, A, Chen, C-TA. 1987. Why is there little anthropogenic CO2 in the Antarctic bottom water? Deep-Sea Research 34:1255–75.Google Scholar
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.Google Scholar
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.Google Scholar
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.Google Scholar
Stuiver, M, Östlund, HG. 1980. GEOSECS Atlantic radiocarbon. Radiocarbon 22:1–24.Google Scholar
Stuiver, M, Östlund, HG. 1983. GEOSECS Indian Ocean and Mediterranean radiocarbon. Radiocarbon 25(1):1–29.Google Scholar
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.Google Scholar
Stuiver, M, Polach, HA. 1977. Reporting of 14C data. Radiocarbon 19(3):355–63.Google Scholar
Taylor, NK. 1995. Seasonal uptake of anthropogenic CO2 in a ocean general circulation model. Tellus 47B:145–69.Google Scholar
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.Google Scholar
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.Google Scholar
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.Google Scholar
Toggweiler, JR, Wallace, D. 1995. Transport capacity for passive tracers. US WOCE Report 1995. p 36–8.Google Scholar
Warner, MJ, Weiss, RF. 1985. Solubilities of chlorofluorocarbons 11 and 12 in water and seawater. Deep-Sea Research 32:1485–97.CrossRefGoogle Scholar
Weiss, RF, Östlund, HG, Craig, H. 1979. Geochemical studies of the Weddell Sea. Deep-Sea Research 26A:1093–120.Google Scholar
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.Google Scholar
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.Google Scholar
Worthington, LV. 1977. The case for near-zero production of Antarctic bottom water. Geochimica Cosmochima Acta 41:1001–6.CrossRefGoogle Scholar
Wunsch, C, Hu, DX, Grant, B. 1983. Mass, heat, salt, and nutrients fluxes in the South Pacific Ocean. Journal of Physical Oceanography 13: 725–753.Google Scholar