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On the 14C to Tritium Relationship in the North Atlantic Ocean

Published online by Cambridge University Press:  18 July 2016

Wolfgang Roether ,
Karl-Otto Münnich  and
Hildegard Schoch
Wolfgang Roether
Affiliation:
Institut für Umweltphysik der Universität Heidelberg, Im Neuenheimer Feld 366, D-69 Heidelberg, West Germany
Karl-Otto Münnich
Affiliation:
Institut für Umweltphysik der Universität Heidelberg, Im Neuenheimer Feld 366, D-69 Heidelberg, West Germany
Hildegard Schoch
Affiliation:
Institut für Umweltphysik der Universität Heidelberg, Im Neuenheimer Feld 366, D-69 Heidelberg, West Germany
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Abstract

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Nuclear-weapon produced 14C (or bomb 14C) in the ocean can be traced by simultaneous tritium observations. Data are presented on the general relationship of bomb 14C and tritium in the North Atlantic. For the period 1965 to 1973, the excess 14C to tritium ratios in the surface water vary, systematically, over a factor of 10: the ratios monotonically increase with time, and decrease with latitude, particularly so for the later observations. The sub-surface water ratios show that the mid- and low-latitude water below about the 15° C isothermal horizon (~500m depth) originates from higher northern latitudes, rather than being renewed by local vertical mixing. It is further shown that in the North Atlantic, bomb 14C did not penetrate beyond the horizon where the presently observed 14C concentration is Δ14C = —75‰. Observed concentrations up to about —40‰ can be corrected for a bomb contribution if the tritium concentration is known because the bomb 14C to tritium concentration ratio is rather uniform in this range. A surface water 14C concentration versus time curve is presented for the period since 1957. This curve is based on a North Atlantic mixing model and is fitted to the 14C observations. Making use of a previously published tritium versus time curve obtained by the same model, a time curve for the average excess 14C to tritium ratio in North Atlantic surface water is given. This curve reproduces the observations well. The presented data and theoretical curves show the usefulness of simultaneous 14C and tritium observations for mixing studies and to provide corrections for bomb 14C in sub-surface 14C data in the North Atlantic.

Type
Oceanography
Information
Radiocarbon , Volume 22 , Issue 3: Heidelberg , 1980 , pp. 636 - 646
Copyright
Copyright © The American Journal of Science

References

Bien, G S, Rakestraw, N W, and Suess, H E, 1960, Radiocarbon concentration in Pacific Ocean water: Tellus, v 12, p 436–443.Google Scholar
Broecker, W S, 1979, A revised estimate for the radiocarbon age of North Atlantic deep water: Jour Geophys Research, v 84, no. C6, p 3218–3226.Google Scholar
Broecker, W S and Olson, E A, 1961, Lamont radiocarbon measurements VIII: Radiocarbon, v 3, p 176–204.Google Scholar
Broecker, W S, Gerard, R, Ewing, M, and Heezen, B C, 1960, Natural radiocarbon in the Atlantic Ocean: Jour Geophys Research, v 65, no. 9, p 2903–2931.Google Scholar
Broecker, W S, Peng, T-H, and Stuiver, Minze, 1978, An estimate of the upwelling rate in the equatorial Atlantic based on the distribution of bomb radiocarbon: Jour Geophys Research, v 83, p 6179–6186.Google Scholar
Dreisigacker, E and Roether, Wolfgang, 1978, Tritium and 90Sr in North Atlantic surface water: Earth Planetary Sci Letters, v 38, p 301–312.Google Scholar
Östlund, H G, Dorsey, H G, and Brescher, R, 1976, GEOSECS Atlantic radiocarbon and tritium results (Miami): Rosenstiel School Marine Atmospheric Sci, Univ Miami, Tritium laboratory data rept no. 5.Google Scholar
Peng, T-H, Broecker, W S, Mathieu, G G, Li, Y-H, and Bainbridge, A E, 1979 Radon evasion rates in the Atlantic and Pacific Oceans as determined during the GEOSECS program: Jour Geophys Research, v 84, no. C5, p 2471–2486.Google Scholar
Ribbat, B, Roether, Wolfgang, and Münnich, K O, 1976, Turnover of eastern Caribbean deep water from 14C measurements: Earth Planetary Sci Letters, v 32 p 331–341.Google Scholar
Roether, Wolfgang, 1971, Flushing of the Gerard-Ewing large-volume water sampler: Jour Geophys Research, v 76, p 5910–5912.Google Scholar
Roether, Wolfgang ms, 1972, Die Korrelation von kernwaffenerzeugtem Kohlenstoff-14 und Tritium im Nordatlantik: Habil Schrift, Univ Heidelberg 42 p.Google Scholar
Roether, Wolfgang and Münnich, K O, 1972, Tritium profile at the Atlantic 1970 GEOSECS test cruise station: Earth Planetary Sci Letters v 16 p 127–130.Google Scholar
Roether, Wolfgang, Münnich, K O, Ribbat, B, and Sarmiento, J L, in press A transatlantic C-14 section near 40° N: “METEOR” Forsch-Ergebn A in press.Google Scholar
Roether, Wolfgang and Weiss, Wolfgang, 1978, A transatlantic tritium section near 40° N, 1971: “METEOR” Forsch-Ergebn A, v 20, p 101–108.Google Scholar
Stuiver, Minze, 1976, The 14C distribution in west Atlantic abyssal waters: Earth Planetary Sci Letters, v 32, p 322–330.Google Scholar
Stuiver, Minze 1978. Atmospheric carbon dioxide and carbon reservoir changes: Science, v 199, no. 4326, p 253–258.Google Scholar
Suess, H E, 1955, Radiocarbon concentration in modern wood: Science, v 122, p 415–417.Google Scholar
Weiss, Wolfgang, Roether, Wolfgang, and Bader, G, 1976, Determination of blanks in low-level tritium measurement: Internatl Jour Appl Radiation Isotopes, v 27, p 217–225.Google Scholar
Weiss, Wolfgang, Roether, Wolfgang, and Dreisigacker, E, 1979, Tritium in the North Atlantic Ocean: inventory, input and transfer into the deep water, in The behaviour of tritium in the environment: Vienna, IAEA, p 315–336.Google Scholar