“…However, few studies have examined the biotic effects on the oxidation/reduction of Pu under atmospheric conditions. Lichens occur worldwide (Nash, 1996), and on account of their dominance in certain terrestrial ecosystems (especially arctic/antarctic tundra regions), play a major role in plant ecology and the cycling of some elements, such as C, N and P (Knops et al, 1991;Nash, 1996), and radionuclides (Shaw and Bell, 1994). The ability of lichens to accumulate metals has led to their use in monitoring Pu fallout from accidents e.g.…”