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

• Published in: Radiocarbon
• Main Authors: Stocker, Thomas F., Wright, Daniel G.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1997
• Subjects: Pacific; North Atlantic
• Online Access: https://doi.org/10.1017/s0033822200018233; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033822200018233

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, δ 14 C atm , the surface reservoir ages, the top-to-bottom age differences, and the calendar- 14 C age relationships in different regions of the ocean. The model includes a representation of the cycling of 14 C 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 δ 14 C atm 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 14 C age estimates based on marine organisms that live in the near-surface region of the ocean and take up the signal of surface 14 C can result in apparent age reversals if the assumption of a constant reservoir age is made.