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Radiocarbon in the Water Column of the Southwestern North Pacific Ocean—24 Years After Geosecs

Published online by Cambridge University Press:  18 July 2016

Pavel P Povinec ,
Takafumi Aramaki ,
George S Burr ,
A J Timothy Jull ,
Laval Liong Wee Kwong  and
Orihiko Togawa
Pavel P Povinec*
Affiliation:
International Atomic Energy Agency, Marine Environment Laboratory, Monte-Carlo, MC 98012 Monaco
Takafumi Aramaki
Affiliation:
Japan Atomic Energy Research Institute, Marine Research Laboratory, Mutsu, Aomori-ken, Japan
George S Burr
Affiliation:
University of Arizona, NSF Arizona AMS Facility, Tucson, Arizona, USA.
A J Timothy Jull
Affiliation:
University of Arizona, NSF Arizona AMS Facility, Tucson, Arizona, USA.
Laval Liong Wee Kwong
Affiliation:
International Atomic Energy Agency, Marine Environment Laboratory, Monte-Carlo, MC 98012 Monaco
Orihiko Togawa
Affiliation:
International Atomic Energy Agency, Marine Environment Laboratory, Monte-Carlo, MC 98012 Monaco Japan Atomic Energy Research Institute, Marine Research Laboratory, Mutsu, Aomori-ken, Japan
*
Corresponding author. Email: [email protected].
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Abstract

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In the framework of the Worldwide Marine Radioactivity Studies (WOMARS) project, water profile samples for radiocarbon measurements were taken during the IAEA'97 cruise at 10 stations in the southwestern North Pacific Ocean. While 14C concentrations were rapidly decreasing from the surface (Δ14C about 100‰) down to about 800 m at all visited stations (Δ14C about −200‰), the concentrations below 1000 m were almost constant. Some stations were in proximity to the GEOSECS stations sampled in 1973; thus, 14C profiles could be compared after a 24-yr interval. Generally, 14C concentrations had decreased in surface waters (by 50–80‰) and increased (by about the same amount) in intermediate waters when compared with GEOSECS data. In deep waters (below 1000 m), the observed 14C concentrations were similar to GEOSECS values. The bomb-produced 14C inventory had increased by more than 20% over the 24 yr from 1973 to 1997 and was estimated to be about (32 ± 5) 1012 atom m-2, with an annual 14C flux of (1.3 ± 0.3) 1012 atom m-2 yr-1. The results suggest that bomb-produced 14C has been advected northwards by the Kuroshio Current and the Kuroshio Extension and stored in the intermediate layer as North Pacific Intermediate Water.

Type
Part II
Information
Radiocarbon , Volume 46 , Issue 2: Proceedings of the 18th International Radiocarbon Conference (Part 2 of 2), Conference Editors: Nancy Beavan Athfield, Rodger J Sparks , 2004 , pp. 583 - 594
Copyright
Copyright © The Arizona Board of Regents on behalf of the University of Arizona 

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