Hostname: page-component-586b7cd67f-t7czq Total loading time: 0 Render date: 2024-11-24T00:08:10.976Z Has data issue: false hasContentIssue false

Pre-Bomb Radiocarbon Variability Inferred from a Kenyan Coral Record

Published online by Cambridge University Press:  18 July 2016

Nancy S Grumet
Affiliation:
Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305 USA. Email: [email protected].
Thomas P Guilderson
Affiliation:
Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, California 94551. Also at the Institute of Marine Sciences, University of California at Santa Cruz, Santa Cruz, California 65064 USA.
Robert B Dunbar
Affiliation:
Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305 USA
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

We report results from AMS radiocarbon measurements (δ14C) in corals recovered off the coast of Kenya. Bimonthly samples which span the pre-bomb era average −51 (±3.7; n=43), when age and Suess effect are corrected, and over the time of interest (1946–1954) do not exhibit any discernible seasonality. Relative to regional pre-bomb δ14C values in the western Indian Ocean, our results indicate 14C enrichment off the coast of Kenya. Furthermore, the absence of a distinct subannual δ14C signal suggests that open and coastal upwelling is negligible off the coast of Kenya. Unlike pre-bomb values south of the equator near Seychelles and Madagascar, our pre-bomb value are enriched by more than 10. The enrichment of pre-bomb Kenyan δ14C values relative to sites around Mauritius, northern Madagascar and Seychelles, suggest that the influence of depleted δ14C water transported in the SEC is limited to regions south of 3 to 4°S.

Type
Articles
Copyright
Copyright © 2002 The Arizona Board of Regents on behalf of the University of Arizona 

References

Bard, E, Arnold, M, Ostlund, HG, Maurice, P, Monfray, P, Duplessy, J-C. 1989. 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
Broecker, WS, Peng, T-S, Ostlund, HG, Stuiver, M. 1985. The distribution of bomb radiocarbon in the ocean. Journal of Geophysical Research 90:6953–70.CrossRefGoogle Scholar
Brown, TA, Farwell, GW, Grootes, PW, Schmidt, FH, Stuiver, M. 1993. Intra-annual variability of the radiocarbon content of corals from the Galapagos Islands. Radiocarbon 35(2):245–51.CrossRefGoogle Scholar
Conkright, M, Levitus, S, O'Brien, T, Boyer, T, Antonov, J, Stephens, C. 1998. World Ocean Atlas 1998 CD-ROM Data Set Documentation. Technical Report 15. NODC Internal Report, Silver Springs, Maryland. 16 p.Google Scholar
Davis, JC, Proctor, ID, Southon, JR, Caffee, MW, Heikkinen, DW, Roberts, ML, Moore, TL, Turteltaub, KW, Nelson, DE, Loyd, DH, Vogel, JS. 1990. LLNL/UC AMS facility and research program Nuclear. Instruments and Methods in Physics Research B 52:269–72.Google Scholar
Druffel, EM, Linick, TW. 1978. Radiocarbon in annual coral rings of Florida. Geophysical Research Letters 5:913–6.CrossRefGoogle Scholar
Druffel, EM, Suess, HE. 1983. On the radiocarbon record in banded corals: exchange parameters and net transport of the 14CO2 between atmosphere and surface ocean. Journal of Geophysical Research 88:1271–80.CrossRefGoogle Scholar
Druffel, EM. 1982. Banded corals: changes in oceanic 14C during the Little Ice Age. Science 218:13–9.CrossRefGoogle Scholar
Druffel, ERM. 1989. Decade time scale variability of ventilation in the North Atlantic: high precision measurements of bomb in banded corals. Journal of Geophysical Research 94:3271–85.CrossRefGoogle Scholar
Druffel, ERM. 1997. Geochemistry of corals: Proxies of past ocean chemistry, ocean circulation, and climate. Proceedings of National Academy of Science 94: 8354–61.CrossRefGoogle ScholarPubMed
Druffel, ERM, Griffin, S, Guilderson, TP, Kashgarian, M, Southon, J, Schrag, DP. 2001. Changes in subtropical North Pacific radiocarbon and correlation with climate variability. Radiocarbon 43(1):1525.CrossRefGoogle Scholar
Dutta, K, Bhushan, R, Somayajulu, BLK. 2001. ΔR correction values for the northern Indian Ocean. Radiocarbon 43(2A):483–8.CrossRefGoogle Scholar
Grumet, NS, Dunbar, RB, Cole, JE. 2001. Multisite record of climate change from Indian Ocean corals. 9th International Coral Reef Symposium, Bali, Indonesia. Forthcoming.Google Scholar
Guilderson, TP, Schrag, DP, 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 103:24,64150.CrossRefGoogle Scholar
Guilderson, TP, Schrag, DP, Goddard, E, Kashgarian, M, Wellington, GM, Linsley, BK. 2000. Southwest subtropical Pacific surface water in a high-resolution coral record. Radiocarbon 42(2):249–56.CrossRefGoogle Scholar
Key, RM, Quay, PD, Jones, GA, McNichol, AP, von Reden, KF, Schneider, R. 1996. WOCE AMS radiocarbon 1 Pacific Ocean results P6, P16 and P17. Radiocarbon 38(3):425518.CrossRefGoogle Scholar
Levitus, S, Burgett, R, Boyer, T. 1994. World ocean atlas 1994. Volume 3: nutrients. Washington DC: NOAA Atlas NESDIS 3, US Department of Commerce.Google Scholar
Luther, ME. 1999. Interannual variability in the Somali Current 1954–1976. Nonlinear Analysis 35:5983.CrossRefGoogle Scholar
Moore, MD, Schrag, DP, Kashgarian, M. 1997. Coral constraints on the source of the Indonesian throughflow. Journal of Geophysical Research 102:12,35965.CrossRefGoogle Scholar
Obura, D. 1995. Environmental stress and life history strategies, a case study of corals and river sediment from Malindi, Kenya. PhD dissertation. University of Miami.Google Scholar
Oeschger, H, Siegenthaler, U, Schotterer, U, Gugelmann, A. 1975. Box diffusion-model to study carbon-dioxide exchange in nature. Tellus 27:168–92.Google Scholar
Ostuland, HG, Stuiver, M. 1980. GEOSECS Pacific radiocarbon. Radiocarbon 22(1):2553.CrossRefGoogle Scholar
Schott, FA, McCreary, JP. 2001. The monsoon circulation of the Indian Ocean. Progress in Ocean. 51:1123.CrossRefGoogle Scholar
Southon, J, Kashgarian, M, Fontugne, M, Metivier, B, Yim, WWS. 2002. Marine reservoir corrections for the Indian Ocean and Southeast Asia. Radiocarbon 44(1): 167–80.CrossRefGoogle Scholar
Spencer, D, Broecker, WS, Craig, H, Weiss, RF. 1982. Geosecs Indian Ocean Expedition. Volume 6, Sections and Profiles IDOE. National Science Foundation. 140 p.Google Scholar
Stuiver, M, Polach, HA. 1977. Discussion reporting of 14C data. Radiocarbon 19(3):355–63.CrossRefGoogle Scholar
Stuiver, M, Quay, PD. 1981. Atmospheric 14C changes resulting from fossil fuel CO2 release and cosmic ray flux variability. Earth and Planetary Science Letters 53:349362.CrossRefGoogle Scholar
Stuiver, M, Pearson, GW, Braziunas, TF. 1986. Radiocarbon age calibration of marine samples back to 9000 cal BP. Radiocarbon 28(2B):9801021.CrossRefGoogle Scholar
Swallow, JC. 1984. Some aspects of the physical oceanography of the Indian Ocean. Deep-Sea Research 31: 639–50.CrossRefGoogle Scholar
Tomczak, M, Godfrey, JS. 1994. Regional oceanography: an introduction. Oxford: Pergamon Press. 422 p.Google Scholar
Veldhuis, MJW, Kraay, GW, Van Bleijswijk, GD, Baars, MA. 1997. Seasonal and spatial variability in phytoplankton biomass, productivity and growth in the northwestern Indian Ocean: the southwest and northeast monsoon, 1992–1993. Deep-Sea Research I 44: 425–49.Google 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.CrossRefGoogle Scholar
Woodward, EMS, Rees, AP, Stephens, JA. 1999. The influence of the southwest monsoon upon the nutrient bio-geochemistry of the Arabian Sea. Deep-Sea Research II 46:571–91.Google Scholar