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Variability of Monthly Radiocarbon During the 1760S in Corals from the Galapagos Islands

Published online by Cambridge University Press:  18 July 2016

Sheila Griffin
Affiliation:
Department of Earth System Science, University of California, Irvine, California 92697, USA.
Jeomshik Hwang
Affiliation:
Department of Earth System Science, University of California, Irvine, California 92697, USA.
Tomoko Komada
Affiliation:
Department of Earth System Science, University of California, Irvine, California 92697, USA.
Steven R Beaupre
Affiliation:
Department of Earth System Science, University of California, Irvine, California 92697, USA.
Kevin C Druffel-Rodriguez
Affiliation:
Department of Earth System Science, University of California, Irvine, California 92697, USA.
Guaciara M Santos
Affiliation:
Department of Earth System Science, University of California, Irvine, California 92697, USA.
John Southon
Affiliation:
Department of Earth System Science, University of California, Irvine, California 92697, USA.
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Abstract

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Radiocarbon (Δ14C) measurements of monthly samples from a Galapagos surface coral are among the first data sets from the new Keck Carbon Cycle Accelerator Mass Spectrometry laboratory at the University of California, Irvine. An average Δ14C value of −62 is obtained for 144 measurements of samples from monthly coral bands that lived from about AD 1760–1771 (±6 yr). High Δ14C values were found during January through March, when upwelling was weak or absent at the Galapagos Islands. Low Δ14C values were obtained mid-year during strong upwelling. The average seasonal variability of Δ14C was 15–25, which is greater than that at other tropical and subtropical locations in the Pacific Ocean because of intense seasonal upwelling at this site. Periods of sustained high Δ14C values were found during 1762–1763 and 1766. A spectral analysis revealed that the spectral density for the Δ14C data displays most of its variance at the 5-yr cycle, which is reflective of El Niño periodicity during the 20th century.

Type
Part II
Copyright
Copyright © The Arizona Board of Regents on behalf of the University of Arizona 

References

Bjerknes, J. 1969. Atmospheric teleconnections from the equatorial Pacific. Monthly Weather Review 97:163–72.Google Scholar
Brown, T, Farwell, G, Grootes, P, Schimidt, F, Stuiver, M. 1993. Intra-annual variability of the radiocarbon content of corals from the Galapagos Islands. Radiocarbon 35(2):245–51.Google Scholar
Druffel, EM. 1981. Radiocarbon in annual coral rings from the eastern tropical Pacific Ocean. Geophysical Research Letters 8:5962.Google Scholar
Druffel, ERM. 1987. Bomb radiocarbon in the Pacific: annual and seasonal timescale variations. Journal of Marine Research 45:667–98.CrossRefGoogle Scholar
Druffel, ERM, Griffin, S, Guilderson, T, Kashgarian, M, Schrag, D. 2001. Changes of subtropical North Pacific radiocarbon and correlation with climate variability. Radiocarbon 43(1):1525.Google Scholar
Dunbar, R, Wellington, G, Colgan, M, Glynn, P. 1991. Eastern tropical Pacific corals monitor low latitude climate of the past 400 years. In: Betancourt, J, Tharp, V, editors. Seventh Annual Pacific Climate (PACLIM) Workshop. California Department of Water Resources. Interagency Ecological Studies Program. p 183–98.Google Scholar
Grottoli, A, Gille, S, Druffel, ERM, Dunbar, R. 2003. Decadal timescale shift in the radiocarbon record of a central equatorial Pacific coral. Radiocarbon 45(1):91–9.Google Scholar
Guilderson, T, Schrag, D. 1998. Abrupt shift in subsurface temperatures in the tropical Pacific associated with changes in El Niño. Science 281:240–3.CrossRefGoogle ScholarPubMed
Guilderson, T, Schrag, D, Goddard, E, Kashgarian, M, Wellington, G, Linsley, B. 2000. Southwest subtropical Pacific surface water radiocarbon in a high-resolution coral record. Radiocarbon 42(2):249–56.Google Scholar
Guilderson, T, Schrag, D, Kashgarian, M, Southon, J. 1998. Radiocarbon variability in the Western Equatorial Pacific inferred from a high-resolution coral record from Nauru Island. Journal of Geophysical Research 103(C11):24,64151.Google Scholar
Richards, AF. 1957. Volcanism in eastern Pacific Ocean basin, 1954–1955. International Geological Congress, Mexico, Proceedings X 1:1931.Google Scholar
Stuiver, M, Polach, HA. 1977. Discussion: reporting of 14C data. Radiocarbon 19(3):355–63.CrossRefGoogle Scholar
Toggweiler, JR, Dixon, K, Broecker, WS. 1991. The Peru upwelling and the ventilation of the South Pacific thermocline. Journal Geophysical Research 96: 20,46797.CrossRefGoogle Scholar
Vogel, JS, Southon, JR, Nelson, DE. 1987. Catalyst and binder effects in the use of filamentous graphite for AMS. Nuclear Instruments and Methods in Physics Research B 29:50–6.Google Scholar