14C Profiles in the Central Weddell Sea

• Published in: Radiocarbon
• Main Authors: Schlosser, Peter, Kromer, Bernd, Bayer, Reinhold, Münnich, K O
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1989
• Subjects: General Earth and Planetary Sciences; Archeology; Weddell Sea; Weddell
• Online Access: http://dx.doi.org/10.1017/s0033822200012133; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033822200012133

14 C data from stations in the central Weddell Sea are presented and discussed using additional parameters (potential temperature, salinity and 3 He). The low 14 C concentrations of the surface water (≈-90‰) are explained by suppressed gas exchange due to ice cover during the winter and rapid turnover of the surface layer caused by entrainment of Warm Deep Water (WDW) with low 14 C concentrations. A simple time-dependent balance calculated for the Surface Water (SW) and the underlying Winter Water (WW) can reproduce the 14 C concentrations observed in these layers for 1985. The pre-bomb 14 C concentrations are estimated at ≈-130‰ for SW and −140‰ for WW. A strong deviation of the SW 14 C concentration observed in 1973 from the calculated value suggest a change in surface circulation and/or air/sea exchange during the period before the Weddell Polynya in 1974. The observed 14 C concentrations of the Weddell Sea Bottom Water (WSBW; −135 to −150‰) are only slightly higher than those of the WDW showing that the uptake of bomb 14 C in the Weddell Sea is limited. The 14 C profiles show a minimum at intermediate depths (≈ 1500m) which is caused by radioactive decay and/or penetration of bomb 14 C from shallow and deep layers (WDW and WSBW) into intermediate layers.