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Zusammenfassung:
We present &4C and 39Ar data collected in the Nansen, Amundsen and Makarov basins during two expeditions
to the central Arctic Ocean (RV Polarstern cruises ARK P1/3, 1987 and ARK VIII/3,1991). The data are used, together with
published e14C values, to describe the distribution of &"C in all major basins of the Arctic Ocean (Nansen, Amundsen,
Makarov and Canada Basins), as well as the 39Ar distribution in the Nansen Basin and the deep waters of the Amundsen and
Makarov Basins. From the combined &4C and 39Ar distributions, we derive information on the mean "isolation ages" of the
deep and bottom waters of the Arctic Ocean. The data point toward mean ages of the bottom waters in the Eurasian Basin
(Nansen and Amundsen Basins) of ca. 250-300 yr. The deep waters of the Amundsen Basin show slightly higher 3H concentrations
than those in the Nansen Basin, indicating the addition of a higher fraction of water that has been at the sea surface
during the past few decades. Correction for the bomb 14C added to the deep waters along with bomb 3H yields isolation ages
for the bulk of the deep and bottom waters of the Amundsen Basin similar to those estimated for the Nansen Basin. This finding
agrees well with the 39Ar data. Deep and bottom waters in the Canadian Basin (Makarov and Canada Basins) are very
homogeneous, with an isolation age of ca. 450 yr. e14C and 39Ar data and a simple inverse model treating the Canadian Basin
Deep Water (CBDW) as one well-mixed reservoir renewed by a mixture of Atlantic Water (29%), Eurasian Basin Deep Water
(69%) and brine-enriched shelf water (2%) yield a mean residence time of CBDW of ca. 300 yr.