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 (228Kb)
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9,637,000 Yen (FY1995 3,222,000 Yen)
Effect of exposure of artificial acid rain (mixture of 0.25mM solution of HCl, HNO3, and H2SO4;(pH 3.5)) on model soils was determined in terms of diversity and ability of carbon source utilization of soil bacteria. Artificial acid rain reduced remarkably both of diversity (56% of control) and number of carbon source utilized (30% of control) of soil bacterial community at 1 day after the exposure. The diversity level was recovered up to 85% of the control in the long term incubation(1 year) but the level of carbon source utilization ability was remained at 44% of the control. It is considered that the bacterial community is shifted to that dominated by strains having simple carbon source utilization ability.
Effects of environmental acidification on soil microbial community both of bacteria and fungi were evaluated in terms of quantity and diversity. Diversities of bacteria and fungi were determined by complexities of carbon source utilization pattern and morphological characteristics pattern, respectively. In quantities measured with the plate counting method, fungi increased but, in contrast, bacteria decreased in some soils acidified compared to a soil unacidified. On the contrary, diversities of both of bacterial and fungal communities remarkably decreased with decrease of pHs of the soils. It is considered that these results strongly suggest that acidification of environment will shift microbial communities to those which are more uniform and are dominated by fungi even in natural soils. Then it may make shrink of material flow systems in environment.
Acidification, Soil Bacteria, Diversity