Campus Units

Geological and Atmospheric Sciences

Document Type

Article

Publication Version

Published Version

Publication Date

2012

Journal or Book Title

Radiocarbon

Volume

54

Issue

2

First Page

165

Last Page

186

Abstract

Marine radiocarbon bomb-pulse time histories of annually resolved archives from temperate regions have been underexploited. We present here series of Δ14C excess from known-age annual increments of the long-lived bivalve mollusk Arctica islandica from 4 sites across the coastal North Atlantic (German Bight, North Sea; Troms⊘, north Norway; Siglufjordur, north Icelandic shelf; Grimsey, north Icelandic shelf) combined with published series from Georges Bank and Sable Bank (NW Atlantic) and the Oyster Ground (North Sea). The atmospheric bomb pulse is shown to be a step-function whose response in the marine environment is immediate but of smaller amplitude and which has a longer decay time as a result of the much larger marine carbon reservoir. Attenuation is determined by the regional hydrographic setting of the sites, vertical mixing, processes controlling the isotopic exchange of 14C at the air-sea boundary, 14C content of the freshwater flux, primary productivity, and the residence time of organic matter in the sediment mixed layer. The inventories form a sequence from high magnitude-early peak (German Bight) to low magnitude-late peak (Grimsey). All series show a rapid response to the increase in atmospheric Δ14C excess but a slow response to the subsequent decline resulting from the succession of rapid isotopic air-sea exchange followed by the more gradual isotopic equilibration in the mixed layer due to the variable marine carbon reservoir and incorporation of organic carbon from the sediment mixed layer. The data constitute calibration scries for the use of the bomb pulse as a high-resolution dating tool in the marine environment and as a tracer of coastal ocean water masses.

Comments

This article is published as Scourse, James D., Alan D. Wanamaker Jr, Chris Weidman, Jan Heinemeier, Paula J. Reimer, Paul G. Butler, Rob Witbaard, and Christopher A. Richardson. "The Marine Radiocarbon Bomb Pulse across the Temperate North Atlantic: A Compilation of Δ 14 C Time Histories from Arctica islandica Growth Increments." Radiocarbon 54, no. 2 (2012): 165-186. Posted with permission.

Copyright Owner

Arizona Board of Regents on behalf of the University of Arizona

Language

en

File Format

application/pdf

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