ACCUMULATION OF GOLD IN THE SHEATH OF PLECTONEMA-TEREBRANS (FILAMENTOUS MARINE CYANOBACTERIA)

Plectonema terebrans, a species of filamentous, marine cyanobacteria, was found to accumulate gold from a solution of AuCl3.H2O in its sheath (glycocalyx). Sheaths are among the few structures likely to be preserved in some form in microfossils of ancient bacteria. Bacteriform gold (hypothesized to conform to the morphologies of various fossilized bacteria) is well known (reviewed in this article). Our research strengthens the idea that some bacteriform gold is biogenic, the result of precipitation by bacteria, and that such gold formations may be important indicators of the pressence of some types of auriferous deposits and of processes of gold accumulation.