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The Effect of a Succession of Ocean Ventilation Changes on 14C

Published online by Cambridge University Press:  18 July 2016

Thomas F. Stocker  and
Daniel G. Wright
Thomas F. Stocker
Affiliation:
Climate and Environmental Physics, Physics Institute, University of Bern, Sidlerstrasse 5 CH-3012 Bern, Switzerland
Daniel G. Wright
Affiliation:
Fisheries and Oceans Canada, Bedford Institute of Oceanography, P.O. Box 1006, Dartmouth Nova Scotia, Canada B2Y 4A2
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Abstract

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Using the model of Stacker and Wright (1996), we investigate the effect of a succession of ocean ventilation changes on the atmospheric concentration of radiocarbon, δ14Catm, the surface reservoir ages, the top-to-bottom age differences, and the calendar-14C age relationships in different regions of the ocean. The model includes a representation of the cycling of 14C through the atmosphere, the ocean and the land biosphere. Ocean ventilation changes are triggered by increasing rates of freshwater discharge into the North Atlantic, which are determined according to a simple feedback mechanism between the melting rates and the climatic state of the North Atlantic region. The results demonstrate that ventilation changes can cause δ14Catm fluctuations of 25%, surface reservoir age fluctuations of 100 yr in the Pacific (200 yr in the Atlantic) and top-to-bottom age variations of 500 yr in the Pacific (1000 yr in the Atlantic). We also show that 14C age estimates based on marine organisms that live in the near-surface region of the ocean and take up the signal of surface 14C can result in apparent age reversals if the assumption of a constant reservoir age is made.

Type
Part 1: Methods
Information
Radiocarbon , Volume 40 , Issue 1: 16th International Radiocarbon Conference 16-20,1997 Groningen , 1997 , pp. 359 - 366
Copyright
Copyright © The American Journal of Science 

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