著者

小川 数也

出版者

日本海洋学会

雑誌

日本海洋学会誌 (ISSN:00298131)

巻号頁・発行日

vol.30, no.2, pp.54-60, 1974-04-30 (Released:2011-06-17)

参考文献数

34

被引用文献数

4

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Some experiments were carried out to explain the in situ phenomena that the number of coliform organisms decreased rapidly from estuaries to offshore, and also at deeper layer, and that the appearance of coliform types varied.In natural seawater, experimental results did not show that Escherichia coli was extinct by self-purification or anti-biosis action of seawater, but it showed that this organism decreased mainly because of their starvation caused by lack of nourishment. Although the decreasing rate of bacterial density was delayed in enriched seawater, addition ofnutrient even at the time of bacterial extinction promoted the appearance of variated form of this bacteria with floc formation.Flocculation of bacterial cells was influenced by quality and quantity of added nutrients. Temperature was shown to have an effect on the floc formation, but appearance of variated form in flocculated cells of E. coli was not affected by temperature. Flocculated particles of coliform bacteria were adsorbed on suspended particles in seawater and precipitated rapidly. This phenomenon seems to be a cause of the rapid disappearance of coliform bacteria in coastal waters.In bottom deposits the coliform bacteria probably survive longer as physiologically variated forms when suitable nutrients were supplied.