Abstract
The distribution of manganese-oxidizing bacteria in the sediments from near-shore (Kumano Basin) and deep-sea (Shikoku Basin) was investigated together with redox factors such as redox potential (Eh), reducible manganese (Red-Mn) and iron (Red-Fe).The manganese-oxidizing bacteria in the cores were concentrated in the oxidizing zones near the sediment surface (Eh>540mV;Red-Mn>0.1mg g-1), and decreased as the sediment was reduced.The total number of bacteria in oxidizing sediments were about 1×107 CFU g-1 and about 65% were manganese-oxidizing bacteria. However, any direct relationship between manganese-oxidizing bacteria and the redox factors was notfound.
The dominant genera of manganese-oxidizing bacteria found in this study wereVibriosp., Alcaligenes sp.andPseudomonassp.of motile Gram-negative rods that were positive in catalase and oxidase tests, andMoraxellasp.with the same characteristics except for motility.Manganese-oxidizing bacteria identified in the near-shore sediment was onlyVibriosp., and those in the deep-sea sediments wereAlcaligenessp., Pseudomonassp.andMoraxellasp.
