Skip to main content Accessibility help

The Passage of the Bomb Radiocarbon Pulse into the Pacific Ocean

  • William J Jenkins (a1), Kathryn L Elder (a1), Ann P McNichol (a1) and Karl von Reden (a1)


We report and compare radiocarbon observations made on 2 meridional oceanographic sections along 150°W in the South Pacific in 1991 and 2005. The distributions reflect the progressive penetration of nuclear weapons-produced 14C into the oceanic thermocline. The changes over the 14 yr between occupations are demonstrably large relative to any possible drift in our analytical standardization. The computed difference field based on the gridded data in the upper 1600 m of the section exhibits a significant decrease over time (approaching 40 to 50‰ in Δ14C) in the upper 200–300 m, consistent with the decadal post-bomb decline in atmospheric 14C levels. A strong positive anomaly (increase with time), centered on the low salinity core of the Antarctic Intermediate Water (AAIW), approaches 50–60‰ in Δ14C, a clear signature of the downstream evolution of the 14C transient in this water mass. We use this observation to estimate the transit time of AAIW from its “source region” in the southeast South Pacific and to compute the effective reservoir age of this water mass. The 2 sections show small but significant changes in the abyssal 14C distributions. Between 1991 and 2005, Δ14C has increased by 9‰ below 2000 m north of 55°S. This change is accompanied overall by a modest increase in salinity and dissolved oxygen, as well as a slight decrease in dissolved silica. Such changes are indicative of greater ventilation. Calculation of “phosphate star” also indicates that this may be due to a shift from the Southern Ocean toward North Atlantic Deep Water as the ventilation source of the abyssal South Pacific.

    • Send article to Kindle

      To send this article to your Kindle, first ensure 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 or variations. ‘’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘’ 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.

      The Passage of the Bomb Radiocarbon Pulse into the Pacific Ocean
      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.

      The Passage of the Bomb Radiocarbon Pulse into the Pacific Ocean
      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.

      The Passage of the Bomb Radiocarbon Pulse into the Pacific Ocean
      Available formats


Corresponding author

Corresponding author. Email:


Hide All
Bainbridge, AE, Ostlund, HG, Craig, H, Broecker, WS, Spencer, DW. 1987. GEOSECS Atlantic, Pacific, and Indian Ocean expeditions: shore-based data and graphics. GEOSECS ATLAS, 7. 200 p.
Broecker, WS, Peng, T-H. 1980. The distribution of bomb-produced tritium and radiocarbon at GEOSECS station 347 in the eastern North Pacific. Earth and Planetary Science Letters 49(2):453–62.
Broecker, WS, Peng, T-H, Ostlund, HG, Stuiver, M. 1985. The distribution of bomb radiocarbon in the ocean. Journal of Geophysical Research 90(C90):6953–70.
Broecker, WS, Sutherland, S, Peng, T-H. 1999. A possible 20th-century slowdown of Southern Ocean deep water formation. Science 286(5442):1132–5.
Broecker, WS, Sutherland, SC, Smethie, WM, Peng, T-H, Ostlund, HG. 1995. Oceanic radiocarbon: separation of the natural and bomb components. Global Biogeochemical Cycles 9(2):263–88.
Butzin, M, Prange, M, Lohmann, G. 2005. Radiocarbon simulations for the glacial ocean: the effects of wind stress, Southern Ocean sea ice and Heinrich events. Earth and Planetary Science Letters 235(1–2):4561.
Craig, H. 1969. Abyssal carbon and radiocarbon in the Pacific. Journal of Geophysical Research 74(23):5491–506.
Doney, S, Hecht, MW. 2002. Antarctic Bottom Water formation and deep-water chlorofluorocarbon distributions in a global ocean climate model. Journal of Physical Oceanography 329(6):1642–66.
Druffel, EM, Suess, HE. 1983. On the radiocarbon record in banded corals: exchange parameters and net transport of 14CO2 between atmosphere and surface ocean. Journal of Geophysical Research 88(C2):1271–80.
Elder, KL, McNichol, AP, Gagnon, AR. 1998. Evaluating reproducibility of seawater, inorganic and organic carbon 14C results at the National Ocean Sciences AMS Facility (NOSAMS). Radiocarbon 40(1):223–30.
England, MH, Maier-Reimer, E. 2001. Using chemical tracers to assess ocean models. Reviews of Geophysics 39(1):2970.
Georgi, DT. 1979. Modal properties of Antarctic Intermediate Water in the Southeast Pacific and the South Atlantic. Journal of Physical Oceanography 9(3):456–8.
Hua, Q, Barbetti, M. 2004. Review of tropospheric bomb 14C data for carbon cycle modeling and age calibration purposes. Radiocarbon 46(3):1273–98.
Iudicone, D, Rodgers, KB, Schopp, R, Madec, G. 2007. An exchange window for the injection of Antarctic Intermediate Water into the South Pacific. Journal of Physical Oceanography 37(1):3149.
Jenkins, WJ, Rhines, PB. 1980. Tritium in the deep North Atlantic Ocean. Nature 286(5776):877–80.
Key, RM. 1996. WOCE Pacific Ocean radiocarbon program. Radiocarbon 38(3):415–23.
Key, RM, Quay, P, Jones, GA, McNichol, AP, von Reden, K, Schneider, RJ. 1996. WOCE AMS radiocarbon I: Pacific Ocean results (P6, P16 and P17). Radiocarbon 38(3):425518.
Key, RM, Quay, P, Schlosser, P, McNichol, AP, von Reden, K, Schneider, B, Elder, KL, Stuiver, M, Ostlund, HG. 2002. WOCE Radiocarbon IV: Pacific results; P10, P13N, P14C, P18, P19 & S4P. Radiocarbon 44(1):239392.
Kuhlbrodt, T, Griesel, A, Montoya, M, Levemann, A, Hofmann, M, Rahmstorf, S. 2007. On the driving processes of the Atlantic meridional overturning circulation. Reviews of Geophysics 45: RG2001, doi:10.1029/2004RG000166.
Liu, Z, Alexander, M. 2007. Atmospheric bridge, oceanic tunnel, and global climate teleconnections. Reviews of Geophysics 45: RG2005, doi:10.1029/2005RG000172.
Mahadevan, A. 2001. An analysis of bomb radiocarbon trends in the Pacific. Marine Chemistry 73(3–4):273–90.
McCartney, MS. 1977. Subantarctic mode water. In: Angel, M, editor. A Voyage of Discovery. Oxford: Pergammon Press. p 103–19.
McCreary, JP, Lu, P. 1994. Interaction between the subtropical and equatorial ocean circulations: the subtropical cell. Journal of Physical Oceanography 24(2):466–97.
McNeil, BI, Matear, RJ, Key, RM, Bullister, JL, Sarmiento, JL. 2003. Anthropogenic CO2 uptake by the ocean based on the global chlorofluorocarbon data set. Science 229(5604):235–9.
McNichol, AP, Gagnon, AR, Jones, GA, Osborne, EA. 1992. Illumination of a black box: analysis of gas composition during graphite target preparation. Radiocarbon 34(3):321–9.
McNichol, AP, Jones, GA, Hutton, DL, Gagnon, AR. 1994. The rapid preparation of seawater ΣCO2 for radiocarbon analysis at the National Ocean Sciences AMS Facility. Radiocarbon 36(2):237–46.
Munk, WH. 1966. Abyssal recipes. Deep-Sea Research 13:707–30.
Ostlund, HG, Dorsey, HG, Rooth, CG. 1974. GEOSECS North Atlantic radiocarbon and tritium results. Earth and Planetary Science Letters 23(1):6986.
Reid, JL. 1986. On the total geostrophic circulation of the South Pacific Ocean: flow patterns, tracers and transports. Progress in Oceanography 16(1):161.
Reimer, PJ, Reimer, RW. 2001. A marine reservoir correction database and on-line interface. Radiocarbon 43(2A):461–3.
Rodgers, KB, Aumont, O, Madec, G, Menkes, C, Blanke, B, Monfray, P, Orr, JC, Schrag, D. 2004. Radiocarbon as a thermocline proxy for the eastern equatorial Pacific. Geophysical Research Letters 31: L14314, doi:10.1029/2004GL019764.
Rubin, SI, Key, RM. 2002. Separating natural and bomb-produced radiocarbon in the ocean: the potential alkalinity method. Global Biogeochemical Cycles 16(4):1105, doi:10.1029/2001GB001432.
Schlosser, P, Bullister, JL, Fine, RA, Jenkins, WJ, Key, RM, Lupton, JE, Roether, W, Smethie, WM. 2001. Transformation and age of water masses. In: Siedler, G, Church, J, Gould, J, editors. Ocean Circulation and Climate: Observing and Modelling the Global Ocean. International Geophysics Series. San Diego: Academic Press. p 431–52.
Scott, EM, Bryant, C, Cook, GT, Naysmith, P. 2003. Is there a Fifth International Radicarbon Comparison (VIRI)? Radiocarbon 45(3):493–5.
Smith, WHF, Wessel, P. 1990. Gridding with continuous curvature splines in tension. Geophysics 55(3):293305.
Stuiver, M, Polach, HA. 1977. Discussion: reporting of 14C data. Radiocarbon 19(3):355–63.
Vogel, JS, Southon, JR, Nelson, DE. 1987. Catalyst and binder effects in the sues of filamentous graphite for AMS. Nuclear Instruments and Methods in Physics Research B 29(1):50–6.
Waugh, DW, Hall, TM, McNeil, BI, Key, RM, Matear, RJ. 2006. Anthropogenic CO2 in the oceans estimated using transit time distributions. Tellus B 58(5):376–89.


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