Tracer Applications of Anthropogenic Iodine-129 in the North Atlantic Ocean.
Abstract
I (t(1/2)=15.7 x 10(6)y) has been released to the oceans in large quantities (over 5 times the pre-existing natural inventory) by nuclear fuel reprocessing facilities in northwestern Europe since the 1960's. (129)I was measured by AMS in 11 archived seawater samples (collected from 1969 to 1981) and 83 samples collected in 1993 from 9 stations in the southern Greenland and Norwegian Seas and the high latitude North Atlantic Ocean. Reprocessing-derived (129)I is evident in all of the major water masses sampled. The distribution of (129)I is markedly different from that of the chlorofluorocarbons freon-11 and carbon tetrachloride, reflecting the different nature of the source functions of the tracers. Modeled distributions of (129)I in the surface waters of the Barents, Greenland, and Norwegian Seas, agree well with observations. The most striking result of these models is their prediction that the biogeochemical transport of 129(I) to the deep waters studied cannot be distinguished from physical transport given current measurement capabilities. The use of 129(I) as a tracer of new production will require sampling of a slowly ventilated deep water mass underlying surface waters of high productivity and/or very high 129(I).
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1997
- Accession Number
- ADA330113
Entities
People
- Henrietta N. Edmonds
Organizations
- Massachusetts Institute of Technology