A Time History of Pre- and Post-Bomb Radiocarbon in the Barents Sea Derived from Arcto-Norwegian Cod Otoliths

• Published in: Radiocarbon
• Main Authors: Kalish, John M, Nydal, Reidar, Nedreaas, Kjell H, Burr, George S, Eine, Gro L
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 2001
• Subjects: Barents Sea; North Atlantic
• Online Access: https://doi.org/10.1017/s0033822200041515; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033822200041515

Radiocarbon measured in seawater dissolved inorganic carbon (DIC) can be used to investigate ocean circulation, atmosphere/ocean carbon flux, and provide powerful constraints for the fine-tuning of general circulation models (GCMs). Time series of 14 C in seawater are derived most frequently from annual bands of hermatypic corals. However, this proxy is unavailable in temperate and polar oceans. Fish otoliths, calcium carbonate auditory, and gravity receptors in the membranous labyrinths of teleost fishes, can act as proxies for 14 C in most oceans and at most depths. Arcto-Norwegian cod otoliths are suited to this application due to the well-defined distribution of this species in the Barents Sea, the ability to determine ages of individual Arcto-Norwegian cod with a high level of accuracy, and the availability of archived otoliths collected for fisheries research over the past 60 years. Using measurements of 14 C derived from Arcto-Norwegian cod otoliths, we present the first pre- and post-bomb time series (1919–1992) of 14 C from polar seas and consider the significance of these data in relation to ocean circulation and atmosphere/ocean flux of 14 C. The data provide evidence for a minor Suess effect of only 0.2‰ per year between 1919 and 1950. Bomb 14 C was evident in the Barents Sea as early as 1957 and the highest 14 C value was measured in an otolith core from a cod with a birth date of 1967. The otolith 14 C data display key features common to records of 14 C obtained from a Georges Bank mollusc and corals from the tropical and subtropical North Atlantic.