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14C Profiles in the Central Weddell Sea

Published online by Cambridge University Press:  18 July 2016

Peter Schlosser ,
Bernd Kromer ,
Reinhold Bayer  and
K O Münnich
Peter Schlosser
Affiliation:
Institut für Umweltphysik der Universität Heidelberg Im Neuenheimer Feld 366, D-69 Heidelberg, FRG
Bernd Kromer
Affiliation:
Institut für Umweltphysik der Universität Heidelberg Im Neuenheimer Feld 366, D-69 Heidelberg, FRG
Reinhold Bayer
Affiliation:
Institut für Umweltphysik der Universität Heidelberg Im Neuenheimer Feld 366, D-69 Heidelberg, FRG
K O Münnich
Affiliation:
Institut für Umweltphysik der Universität Heidelberg Im Neuenheimer Feld 366, D-69 Heidelberg, FRG
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Abstract

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14C data from stations in the central Weddell Sea are presented and discussed using additional parameters (potential temperature, salinity and 3He). The low 14C 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 14C concentrations. A simple time-dependent balance calculated for the Surface Water (SW) and the underlying Winter Water (WW) can reproduce the 14C concentrations observed in these layers for 1985. The pre-bomb 14C concentrations are estimated at ≈-130‰ for SW and −140‰ for WW. A strong deviation of the SW 14C 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 14C 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 14C in the Weddell Sea is limited. The 14C profiles show a minimum at intermediate depths (≈ 1500m) which is caused by radioactive decay and/or penetration of bomb 14C from shallow and deep layers (WDW and WSBW) into intermediate layers.

Type
II. Carbon Cycle in the Environment
Information
Radiocarbon , Volume 31 , Issue 3: June 20-25, 1988 Dubrovnik, Yugoslavia , 1989 , pp. 544 - 556
Copyright
Copyright © The American Journal of Science 

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