Biomethylation of thallium by bacteria and first determination of biogenic dimethylthallium in the ocean

Geochemistry of Peruvian near-surface sediments

“…These elements are involved in nutrient-type bio-cycling processes and characterized by surface-seawater depletion (see compilation in Bruland, 1983;Schedlbauer and Heumann, 2000). At the same time most of these TE are enriched in plankton (see Brumsack, 1986 and references therein).…”

“…Flegal et al (1986) suggested that biological activity may be of importance for T1 export to the deep ocean. The likely involvement of T1 in bio-cycling is indicated by recent measurements of T1 in a sea water profile exhibiting a significant surface water depletion in total dissolved T1 and elevated contents of biomethylated T1 (Schedlbauer and Heumann, 2000). However, to date the behavior of T1 under reducing conditions and its mechanism of accumulation is essentially unknown.…”

“…The involvement of T1 in bio-cycling (Schedlbauer and Heumann, 2000) implies input of T1 through settling biodetritus. The high sulfur contents and the proposed affinity of reduced T1 to pyrite (Heinrichs et al, 1980) suggest trapping of T1 with sulfides in Peruvian sediments.…”