磐梯湖沼の微生物学的研究 : VI赤沼湖群の微生物相

抄録

Ecological studies on microbes were carried out in the Akanuma Lake Group of Volcano Bandai, Fukushima Prefecture. The lake waters showed strong acidity of pH 3.8〜4.4 and contained large amounts of mineral elements. The bacteria were counted 5〜50/cc in the water and 0.5〜150×10^4/g in the bottom mud. When the lake waters were inoculated at 30℃ for 24 hours, the bacteria increased 330〜14000 times the initial amounts in Lake Kokenuma, Hyotannuma and Aodoronuma. But no multiplication of bacteria was observed in the lake water of Lake Akanuma. The bacteria of acidotrophic lakes flourished in the lake waters of the Akanuma Group, while that of the harmonic lakes showed no increase. The zoospores of aquatic Phycomycetes were very abundant in Lake Akanuma and Hyotannuma. Saprolegnia monoica var. acidamica, which showed high resistivity against the high concentration of the mineral components, was the only species in these lakes. The frequency of the fungi in the bottom mud ranged from 70 to 100 per cent to the total mud samples. The fungi were counted to be 250〜3500/1 in the water and 1000〜2000/g in the bottom mud. The species of the fungi were relatively scarce compared with that of the harmonic lakes. The lakes of the Akanuma Group belong to the typical acidotrophic type. The community of microbe was very scarce in quantity as well as in quality.