阿蘇海・宮津湾の水中および海底堆積物中におけるNi耐性菌の分布

抄録

The distribution of Ni-tolerant bacteria in sea water and bottom sediments of the Sea of Aso was observed and compared with that of the total heterotrophic bacteria. The Sea of Aso is a narrow and closed area of the sea adjacent to Miyazu Bay and has long received in-dustrial waste water containing Ni from a metallurgical factory. It was found that popula-tion densities of the total heterotrophic bacteria counted by means of Z_OBELL 2216E medium ranged from l0³ to 10⁵/ml in sea water and from 10⁴ to l0₅/g (wet basis) in bottom sediments. Most of these bacteria failed to grow on the medium containing Ni at a concentration of 1000 μg/ml. The numerical ratio of the Ni-tolerant bacteria to the total heterotrophic bacteria was relatively high in the heavily polluted area as compared with an unpolluted area. The ratio was found to correlate closely with the concentration of Ni in bottom sediments in the Sea of Aso. It is suggested that the above-mentioned ratio can be used as an index for the extent of environmental pollution by Ni in the coastal sea areas.