Sulfate-Reducing Bacteria and Pyritic Sediments in Antarctica

Black lacustrine and marine sediments occur in the McMurdo Sound region of Antarctica. The black color is due to the presence of iron sulfide, precipitated by sulfate-reducing bacteria (Desulfovibrio) in the presence of decaying organic matter of algal origin. Viability of sulfate-reducing bacteria in the sediments was demonstrated in the laboratory by culturing in anaerobic liquid media. It is probable that sulfate-reducing bacteria are widely distributed in Antarctica.